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Sample records for 40k 232th 235u

  1. Investigation of (235)U, (226)Ra, (232)Th, (40)K, (137)Cs, and heavy metal concentrations in Anzali international wetland using high-resolution gamma-ray spectrometry and atomic absorption spectroscopy.

    PubMed

    Zare, Mohammad Reza; Kamali, Mahdi; Fallahi Kapourchali, Maryam; Bagheri, Hashem; Khoram Bagheri, Mahdi; Abedini, Ali; Pakzad, Hamid Reza

    2016-02-01

    Measurements of natural radioactivity levels and heavy metals in sediment and soil samples of the Anzali international wetland were carried out by two HPGe-gamma ray spectrometry and atomic absorption spectroscopy techniques. The concentrations of (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs in sediment samples ranged between 1.05 ± 0.51-5.81 ± 0.61, 18.06 ± 0.63-33.36 ± .0.34, 17.57 ± 0.38-45.84 ± 6.23, 371.88 ± 6.36-652.28 ± 11.60, and 0.43 ± 0.06-63.35 ± 0.94 Bq/kg, while in the soil samples they vary between 2.36-5.97, 22.71-38.37, 29.27-42.89, 472.66-533, and 1.05-9.60 Bq/kg for (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. Present results are compared with the available literature data and also with the world average values. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. Heavy metal concentrations were found to decrease in order as Fe > Mn > Sr > Zn > Cu > Cr > Ni > Pb > Co > Cd. These measurements will serve as background reference levels for the Anzali wetland. PMID:26490904

  2. Investigation of (235)U, (226)Ra, (232)Th, (40)K, (137)Cs, and heavy metal concentrations in Anzali international wetland using high-resolution gamma-ray spectrometry and atomic absorption spectroscopy.

    PubMed

    Zare, Mohammad Reza; Kamali, Mahdi; Fallahi Kapourchali, Maryam; Bagheri, Hashem; Khoram Bagheri, Mahdi; Abedini, Ali; Pakzad, Hamid Reza

    2016-02-01

    Measurements of natural radioactivity levels and heavy metals in sediment and soil samples of the Anzali international wetland were carried out by two HPGe-gamma ray spectrometry and atomic absorption spectroscopy techniques. The concentrations of (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs in sediment samples ranged between 1.05 ± 0.51-5.81 ± 0.61, 18.06 ± 0.63-33.36 ± .0.34, 17.57 ± 0.38-45.84 ± 6.23, 371.88 ± 6.36-652.28 ± 11.60, and 0.43 ± 0.06-63.35 ± 0.94 Bq/kg, while in the soil samples they vary between 2.36-5.97, 22.71-38.37, 29.27-42.89, 472.66-533, and 1.05-9.60 Bq/kg for (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. Present results are compared with the available literature data and also with the world average values. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. Heavy metal concentrations were found to decrease in order as Fe > Mn > Sr > Zn > Cu > Cr > Ni > Pb > Co > Cd. These measurements will serve as background reference levels for the Anzali wetland.

  3. Determination of (226)Ra, (232)Th, (40)K, (235)U and (238)U activity concentration and public dose assessment in soil samples from bauxite core deposits in Western Cameroon.

    PubMed

    Mekongtso Nguelem, Eric Jilbert; Moyo Ndontchueng, Maurice; Motapon, Ousmanou

    2016-01-01

    Determination of activity concentrations in twenty five (25) soil samples collected from various points in bauxite ore deposit in Menoua Division in Western of Cameroon was done using gamma spectrometry based Broad Energy Germanium (BEGe6530) detector. The average terrestrial radionuclides of (40)K, (226)Ra, (232)Th, (235)U and (238)U were measured as 671 ± 272, 125 ± 58, 157 ± 67, 6 ± 3 and 99 ± 69 Bq kg(-1), respectively. The observed activity concentrations of radionuclides were compared with other published values in the world. The outdoor absorbed dose rate in air varied from 96.1 to 321.2 nGy h(-1) with an average of 188.2 ± 59.4 nGy h(-1). The external annual effective dose rate and external hazard index were estimated as 0.23 ± 0.07 mSv year(-1) for outdoor, 0.92 ± 0.29 mSv year(-1) for indoor and 1.13 for the external hazard index, respectively. These radiological safe parameters were relatively higher than the recommended safe limits of UNSCEAR. Consequently, using of soil as building material might lead to an increase the external exposure to natural radioactivity and future applications research need to be conducted to have a global view of radioactivity level in the area before any undergoing bauxite ore exploitation. PMID:27536536

  4. The Concentrations of {sup 40}K, {sup 226}Ra and {sup 232}Th in Soil Sample in Osmaniye (Turkey)

    SciTech Connect

    Akkurt, I.; Guenoglu, K.; Kara, A.; Mavi, B.; Karaboerklue, S.

    2011-12-26

    The {sup 40}K, {sup 226}Ra and {sup 232}Th concentration is due to the magmatic structure of the earth and it can be varied from place to place. Osmaniye is located in the Eastern side of Mediteranean Region. It holds the climatic characteristics of the same region and arises with Middle Taurus Mountains from west to North and with Amonos Mounations in East and West-east parts and is situated between 35 deg. .52'-36 deg. .42' east longitudes and 36 deg. .57'-37 deg. .45' north latitudes. In this study, the natural radioactivity concentrations {sup 40}K, {sup 226}Ra and {sup 232}Th in some soil samples collected in Osmaniye have been investigated. The measurements have been performed using 3x3{sup ''} NaI(Tl) detector system.

  5. [About the contents of 40K, 226Ra and 232Th in forest soils of the Republic of Belarus].

    PubMed

    Perevolotskiĭ, A N; Perevolotskaia, T V

    2014-01-01

    The specific activity of 40K, 232Th and 226Ra in forest soil ecotopes (A2-B2-C2-D2) has been investigated. When the fertility of the soil increases from A2 to D2, then the specific activity of 40K increases in the rooting zone of the soil from 275 ± 6.9 up to 499 ± 11 Bq/kg, 232Th--from 11.8 ± 0.5 to 17.1 ± 1.1 Bq/kg, 226Ra- from 19.2 γ 0.8 to 27.9 ± 1.5 Bq/kg. The calculated capacity of the absorbed dose of γ-radiation conditioned by 40K, 232Th and 226Ra increases from A2 to D2 from 27.5 ± 0.5 to 44.1 ± 1.1 nGy / h at the height of 1 m.

  6. (226)Ra, (232)Th and (40)K contents in soil samples from Garhwal Himalaya, India, and its radiological implications.

    PubMed

    Ramola, R C; Gusain, G S; Badoni, Manjari; Prasad, Yogesh; Prasad, Ganesh; Ramachandran, T V

    2008-09-01

    The exposure of human beings to ionising radiation from natural sources is a continuing and inescapable feature of life on earth. Natural radionuclides are widely distributed in various geological formations and ecosystems such as rocks, soil groundwater and foodstuffs. In the present study, the distribution of (226)Ra, (232)Th and (40)K was measured in soil samples collected from different lithological units of the Thauldhar and Budhakedar regions of Garhwal Himalaya, India. The collected soil samples were analysed using gamma ray spectrometry. The activity concentrations of the naturally occurring radionuclides (226)Ra, (232)Th and (40)K in these soil samples were found to vary from below detection level (BDL) to 131 +/- 18 Bq kg(-1), 9 +/- 6 to 384 +/- 53 Bq kg(-1) and 471 +/- 96 to 1406 +/- 175 Bq kg(-1), respectively. The distribution of radionuclides depends upon the rock formation and chemical properties within the earth. The activity concentrations vary widely depending on the sample origin. The external absorbed gamma dose rates due to (226)Ra, (232)Th and (40)K were found to vary from 49 to 306 nGy h(-1). The average radium equivalent activity from these soil samples was 300 Bq kg(-1).

  7. Potential sources affecting the activity concentrations of 238U, 235U, 232Th and some decay products in lettuce and wheat samples.

    PubMed

    Jeambrun, M; Pourcelot, L; Mercat, C; Boulet, B; Pelt, E; Chabaux, F; Cagnat, X; Gauthier-Lafaye, F

    2012-11-01

    The activity concentrations of radionuclides within the uranium and thorium series were determined in wheat and lettuce at five sites in France, and in their respective potential sources: crop soils of wheat and crop soils and irrigation waters of lettuce. These data were used to calculate concentration ratios and to enrich the database supported by the technical report series N°472 of the IAEA (2010). For wheat and lettuce, the activity concentrations were in the same range for all radionuclides studied, except for (210)Pb, which had higher activity concentrations in wheat, ranging between 1.3 and 11 Bq kg(−1) (fresh weight) as compared to 0.4 and 0.7 Bq kg(−1) (fresh weight) for lettuce. For wheat, the range of activity concentrations (mBq kg(−1); fresh weight) decreased as (210)Pb > (226)Ra (56–1511) ≈ (228)Ra (86–769) > (228)Th (19–176) ≈ (238)U (11–169) ≈ (234)U (12–150) ≈ (230)Th (9.08–197.18) ≈ (232)Th (8.61–121.45) > (235)U (0.53–7.9). For lettuce, it decreased as (228)Ra (<320–1221) > (210)Pb (409–746) > (226)Ra (30–599) ≈ (228)Th (<29–347) > (238)U (8–120) ≈ (234)U (8–121) ≈ (230)Th (5.21–134.63) ≈ (232)Th (5.25–156.99) > (235)U (0.35–5.63). The species differences may reflect different plant physiologies. Through the study of activity ratios of wheat and lettuce in relation with those of the various radionuclide sources it has been possible to highlight the contribution of the main sources of natural radionuclides. Indeed, irrigation water when the uranium concentration is enhanced (>30 mBq L(−1)) contributed significantly to the activity concentration of uranium in lettuces. Concerning the high activity concentrations of (210)Pb, it could be explained by atmospheric particle deposition. The effect of soil particles resuspension and their adhesion to the plant surface seemed to be important in some cases. The soil-to-plant transfer factors were calculated for lettuce and wheat. The values were

  8. Primordial radioactivity ((238)U, (232)Th and (40)K) measurements for soils of Ludhiana district of Punjab, India.

    PubMed

    Badhan, K; Mehra, R

    2012-11-01

    The aim of the present work was to study the activity concentration and absorbed gamma dose rates due to primordial radionuclides ((238)U, (232)Th and (40)K) for the soil of different villages of Ludhiana district of Punjab, India using a high-purity germanium detector based on high resolution gamma-ray spectrometry. The average activity concentrations of (238)U, (232)Th and (40)K in the soil samples have been found to be 28.58, 50.95 and 569.59 Bq kg(-1), respectively, which gives the total gamma dose rate contribution of 68.50 nGy h(-1). To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the external hazard index, the absorbed dose rate and the effective dose rate have been calculated. The calculated radium equivalent activity values are on the lower side of the recommended safe limit value of 370 Bq kg(-1) by Organization of Economic and Control Department. The calculated value of external health hazard index is lower than unity.

  9. Soil-to-root vegetable transfer factors for (226)Ra, (232)Th, (40)K, and (88)Y in Malaysia.

    PubMed

    Asaduzzaman, Kh; Khandaker, Mayeen Uddin; Amin, Y M; Bradley, D A; Mahat, R H; Nor, R M

    2014-09-01

    Soil-to-plant transfer factors (TFs) are of fundamental importance in assessing the environmental impact due to the presence of radioactivity in soil and agricultural crops. Tapioca and sweet potato, both root crops, are popular foodstuffs for a significant fraction of the Malaysian population, and result in intake of radionuclides. For the natural field conditions experienced in production of these foodstuffs, TFs and the annual effective dose were evaluated for the natural radionuclides (226)Ra, (232)Th, (40)K, and for the anthropogenic radionuclide (88)Y, the latter being a component of fallout. An experimental tapioca field was developed for study of the time dependence of plant uptake. For soil samples from all study locations other than the experimental field, it has been shown that these contain the artificial radionuclide (88)Y, although the uptake of (88)Y has only been observed in the roots of the plant Manihot esculenta (from which tapioca is derived) grown in mining soil. The estimated TFs for (226)Ra and (232)Th for tapioca and sweet potato are very much higher than that reported by the IAEA. For all study areas, the annual effective dose from ingestion of tapioca and sweet potato are estimated to be lower than the world average (290 μSv y(-1)).

  10. Distribution of 226Ra, 232Th and 40K in soils and sugar cane crops at Corumbataí river basin, São Paulo State, Brazil.

    PubMed

    da Conceição, Fabiano Tomazini; Bonotto, Daniel Marcos; Jiménez-Rueda, Jairo Roberto; Roveda, José Arnaldo Frutuoso

    2009-06-01

    The common use of phosphate fertilizers NPK and amendments in sugar cane crops in Brazilian agriculture may increase the (226)Ra, (232)Th and (40)K activity concentrations in soils and their availability for plants and human food chain. Thus, the main aim of this study was to evaluate the distribution of (226)Ra, (232)Th and (40)K in soils and sugar cane crops in the Corumbataí river basin, São Paulo State, Brazil. The gamma spectrometry was utilized to measure the (226)Ra, (232)Th and (40)K activity concentration in all samples. The soil-to-sugar cane transfer factors (TF) were quantified using the ratio between the radionuclide activity concentration in sugar cane and its activity concentration in soil. The results show that, although radionuclides incorporated in phosphate fertilizers and amendments are annually added in the sugar cane crops, if utilized in accordance with the recommended rates, their use does not lead to hazards levels in soils. The soil-to-sugar cane transfer of radionuclides occurred in the following order (40)K>(226)Ra>(232)Th. Therefore, under these conditions, radionuclides intake through consumption of sugar is not hazardous to human health.

  11. 226Ra, 232Th and 40K contents in water samples in part of central deserts in Iran and their potential radiological risk to human population

    PubMed Central

    2014-01-01

    Background The radiological quality of 226Ra, 232Th and 40K in some samples of water resources collected in Anarak-Khour a desertic area, Iran has been measured by direct gamma ray spectroscopy using high purity germanium detector in this paper. Result The concentration ranged from ≤0.5 to 9701 mBq/L for 226Ra; ≤0.2 to 28215 mBq/L for 232Th and < MDA to 10332 mBq/L for 40K. The radium equivalent activity was well below the defined limit of 370Bq/L. The calculated external hazard indices were found to be less than 1 which shows a low dose. Conclusion These results can be contributed to the database of this area because it may be used as disposal sites of nuclear waste in future. PMID:24883192

  12. Measurement of 226Ra, 232Th, 137Cs and 40K activities of Wheat and Corn Products in Ilam Province – Iran and Resultant Annual Ingestion Radiation Dose

    PubMed Central

    CHANGIZI, Vahid; SHAFIEI, Elham; ZAREH, Mohammad Reza

    2013-01-01

    Background: Background: Natural background radiation is the main source of human exposure to radioactive material. Soils naturally have radioactive mineral contents. The aim of this study is to determine natural (238 U, 232 Th, 40 K) and artificial (137 Cs) radioactivity levels in wheat and corn fields of Eilam province. Methods: HPGe detector was used to measure the concentration activity of 238 U and 232 Th series, 40 K and 137 Cs in wheat and corn samples taken from different regions of Eilam province, in Iran. Results: In wheat and corn samples, the average activity concentrations of 226 Ra, 232 Th, 40 K and 137 Cs were found to be 1, 67, 0.5, 91.73, 0.01 and 0.81, 0.85, 101.52, 0.07 Bq/kg (dry weight), respectively. H ex and H in in the present work are lower than 1. The average value of H ex was found to be 0.02 and 0.025 and average value of H in to be found 0.025 and 0.027 in wheat fields samples and corn samples in Eilam provinces, respectively. The obtained values of AGDE are 30.49 mSv/yr for wheat filed samples and 37.89 mSv/yr for corn samples; the AEDE rate values are 5.28 mSv/yr in wheat filed samples and this average value was found to be 6.13 mSv/yr in corn samples in Eilam. Transfer factors (TFs) of long lived radionuclide such as 137 Cs, 226 Ra, 232 Th and 40 K from soils to corn and wheat plants have been studied by radiotracer experiments. Conclusion: The natural radioactivity levels in Eilam province are not at the range of high risk of morbidity and are under international standards. PMID:26056646

  13. Quantification of transfer of (238)U, (226)Ra, (232)Th, (40)K and (137)Cs in mosses of a semi-natural ecosystem.

    PubMed

    Dragović, S; Mihailović, N; Gajić, B

    2010-02-01

    There is a lack of appropriate data on transfer of some radionuclides on many terrestrial biota groups. To expand the available data concentration ratios of (238)U, (226)Ra, (232)Th, (40)K and (137)Cs in mosses are presented in this paper. The relationship between concentration ratios of radionuclides and physicochemical characteristics of the underlying soil was also investigated. The data on concentration ratios obtained here will provide a useful addition to the currently used database of transfer parameters, particularly for natural radionuclides.

  14. Determination of (238)U, (232)Th and (40)K activity concentrations in riverbank soil along the Chao Phraya river basin in Thailand.

    PubMed

    Santawamaitre, T; Malain, D; Al-Sulaiti, H A; Bradley, D A; Matthews, M C; Regan, P H

    2014-12-01

    The activity concentrations of (238)U, (232)Th and (40)K in riverbank soil along the Chao Phraya river basin was determined through gamma-ray spectrometry measurements made using a hyper-pure germanium detector in a low background configuration. The ranges of activity concentrations of (238)U, (232)Th and (40)K were found to be 13.9 ↔ 76.8, 12.9 ↔ 142.9 and 178.4 ↔ 810.7 Bq kg(-1), respectively. The anthropogenic radionuclide, (137)Cs, was not observed in statistically significant amounts above the background level in the current study. The absorbed gamma dose rate in air at 1 m above the ground surface, the outdoor annual effective dose equivalent, the values of the radium equivalent activity and the external hazard index associated with all the soil samples in the present work were evaluated. The results indicate that the radiation hazard from primordial radionuclides in all soil samples from the area studied in this current work is not significant.

  15. Vertical Profiles Of {sup 226}Ra, {sup 232}Th And {sup 40}K Activities In Rocks From The Irati Formation Of The Parana Sedimentary Basin, Southern Brazil

    SciTech Connect

    Ferreira, Ademar de O.; Bastos, Rodrigo O.; Appoloni, Carlos R.

    2008-08-07

    Naturally occurring radioisotopes are present in different concentrations in sedimentary rocks, reflecting the origin of the sediments, the depositional environment, and more recent events such as weathering and erosion. Using a high-resolution {gamma}-ray spectrometry methodology, sedimentary rocks were measured to assess the concentration activities of the natural radioisotopes. The surveyed rocks are from the Irati formation in the Parana sedimentary basin, which are exposed by an abandoned, open-pit limestone mine, in the city of Sapopema, southern Brazil. The exposed vertical profile is 5 m, and its stratigraphy is represented by an alternation of limestone and bituminous shale (layers being a few decimeters thick), and some millimeter rhythm layers with limestone and bituminous shale laminas. Eleven samples were collected along this profile, each of them dried in the open air during 48 hours, sieved through 4 mm mesh and sealed in cylindrical recipients. Measurements were accomplished using a 66% relative efficiency HPGE detector connected to a standard gamma ray spectrometry electronic chain. The detector efficiency in the range of 60 to 1800 keV was carried out with the certified IAEA-385 sediment sample. The Lower Limit of Detection (LLD) to the system is 2.40 Bq{center_dot}kg{sup -1} for {sup 226}Ra, 1.84 Bq{center_dot}kg{sup -1} for {sup 232}Th and 4.20 Bq{center_dot}kg{sup -1} for {sup 40}K. Activity concentrations were determined for {sup 226}Ra (from 16.22 to 151.55 Bq{center_dot}kg{sup -1}), {sup 232}Th (from 2.93 to 56.12 Bq{center_dot}kg{sup -1}) and {sup 40}K (from 38.45 to 644.63 Bq{center_dot}kg{sup -1}). The layers enriched with organic matter presented the higher values of activity. The measured concentrations of the natural radioisotopes were lower for limestone samples (average values and respective deviations were 22.81{+-}0.22 Bq{center_dot}kg{sup -1} for {sup 226}Ra, 4.21{+-}0.07 Bq{center_dot}kg{sup -1} for {sup 232}Th, and 50

  16. Determination of specific activity of (226)Ra, (232)Th and (40)K for assessment of radiation hazards from Turkish pumice samples.

    PubMed

    Turhan, Seref; Gündüz, Lüfullah

    2008-02-01

    The specific activity of (226)Ra, (232)Th and (40)K in 52 Turkish pumice samples collected from 11 geographical areas located in Central Anatolia, Eastern Anatolia, Mediterranean and Aegean regions was determined by gamma-ray spectrometry with a high-purity germanium (HPGe) detector. The specific activity of (226)Ra, (232)Th and (40)K ranged from 12.7+/-0.5 to 256.2+/-9.1Bqkg(-1) with a mean of 89.1+/-65.2Bqkg(-1), 12.3+/-1.0 to 237.9+/-12.2Bqkg(-1) with a mean of 87.0+/-61.4Bqkg(-1) and 300.1+/-5.5 to 1899.0+/-30.8Bqkg(-1) with a mean of 1211.9+/-419.8Bqkg(-1), respectively. Elemental concentrations were determined for U (from 1.0 to 20.7ppm with a mean of 7.2+/-5.3ppm), Th (from 3.0 to 58.6ppm with a mean of 21.4+/-15.1ppm) and K (from 1.0 to 6.1% with a mean of 3.9+/-1.3%). The radium equivalent activity (Ra(eq)), the activity index, the emanation coefficient, the (222)Rn mass exhalation rate, the indoor absorbed dose rate and the effective dose rate were estimated for the radiation hazard of the natural radioactivity in all samples. The calculated mean Ra(eq) value was 306.6+/-177.7Bqkg(-1) (54.6+/-5.5 to 737.6+/-49.0Bqkg(-1)) for all pumice samples. This value is lower than the recommended limit value of 370Bqkg(-1) for building raws and products. The emanation coefficient and the (222)Rn mass exhalation rate of all samples ranged from 29.4 to 42.9% with a mean of 36.2% and from 11.0 to 196.4microBqkg(-1)s(-1) with a mean of 73.5microBqkg(-1)s(-1), respectively. The mean indoor absorbed dose rate and the corresponding mean effective dose rate were 274.6+/-153.6nGyh(-1) (50.4-644.6nGyh(-1)) and 1.35+/-0.75mSvy(-1) (0.24-3.16mSvy(-1)), respectively. For all pumice samples the mean indoor absorbed dose rate is about three times higher than the population-weighted average of 84nGyh(-1), while the mean effective dose rate values except for PUM 05, PUM 06, PUM 10 and PUM 15 exceed the dose criterion of 1mSvy(-1).

  17. Vertical and horizontal distribution of radionuclides (232Th, 238U and 40K) in sediment from Manjung coastal water area Perak, Malaysia

    NASA Astrophysics Data System (ADS)

    Abdullah, Anisa; Hamzah, Zaini; Saat, Ahmad; Wood, Ab. Khalik

    2016-01-01

    Distribution of radionuclides from anthropogenic activities has been widely studied in marine coastal area. Due to rapid population growth and socio-economic development in Manjung area such as coal fired power plant, iron foundries, port development, waste discharged from factories and agriculture runoff may contribute to increase in pollution rate. The radioactive materials from anthropogenic activities could deteriorate the quality of the marine ecosystem and thus lead to possible radiological health risk to the population. Radionuclides (232Th, 238U and 40K) content in surface and profile sediment from Manjung coastal area was determined in this study. Radionuclides in sediment from seven locations were collected using sediment core sampling and measurements were carried out using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopy. The results show that the concentration of radionuclides in surface sediment and distribution trend of depth vertical profile sediment generally varies depending on locations. Enrichment factors (EF), geo-accumulation index (Igeo) and pollution index (PI) were applied to determine level of pollution of this study area. The radiological risks related to human exposure were evaluated based on external hazard index (Hex).

  18. Activity concentrations of 226Ra, 232Th, 40K and 137Cs radionuclides in Turkish medicinal herbs, their ingestion doses and cancer risks

    NASA Astrophysics Data System (ADS)

    Parmaksız, Aydın; Ağuş, Yusuf

    2014-11-01

    Twenty-two medicinal herb samples, each representing a distinct species, were collected from Turkish markets and measured by the gamma spectrometric method. The activity concentration of 226Ra in medicinal herbs was found in the range of minimum detectable activity (MDA) and 15.1 ± 2.2 Bqkg-1. The activity concentration of 232Th ranged from MDA values to 3.5 ± 0.8 Bqkg-1. The activity concentration of 40K varied between 50.0 ± 16.8 and 1311.5 ± 57.3 Bqkg-1. All 137Cs activity concentrations of medicinal herbs were found to have lower than MDA values. The bone surface dose, lower large intestine and colon doses were found to be 182.9, 18.8 and 18.7 µSvy-1, respectively. The highest committed effective dose originated from the annual ingestion of 1 kg medicinal herb was calculated notably low as 9.0 µSv. The cancer risk of ingestion of medicinal herbs was found to be small enough to be neglected. The selected Turkish medicinal herbs are considered safe for human consumption.

  19. (226)Ra, (232)Th and (40)K contents and radon exhalation rate from materials used for construction and decoration in Cameroon.

    PubMed

    Ngachin, M; Garavaglia, M; Giovani, C; Nourreddine, A; Kwato Njock, M G; Scruzzi, E; Lagos, L

    2008-09-01

    This work deals with the measurement of radioactivity and radon exhalation rate from building materials manufactured in Douala city from geological materials. Nine types of building material were surveyed for their natural radioactivity contents using high-resolution gamma-ray spectrometry. The activity concentrations for (226)Ra, (232)Th and (40)K varied from 11.5 to 49 Bq kg(-1), 16 to 37 Bq kg(-1) and 306 to 774 Bq kg(-1), respectively. The absorbed dose rate in the samples investigated at 1 m above ground level ranged from 28.5 to 66.6 nGy h(-1). External and internal hazard indices were also estimated as defined by the European Commission. The Ra equivalents of the materials studied ranged from 57.5 to 133 Bq kg(-1) and are much smaller than the recommended limit of 370 Bq kg(-1) for construction materials for dwellings. Polycarbonate nuclear track detectors (NTDs), type CR-39, were used for measuring the radon concentration from different materials. In fact, knowledge of the radon exhalation rate from building materials is important for understanding the individual contribution of each material to the total indoor radon exposure. Samples were hermetically closed in glass vessels and the radon growth was followed as a function of time. The radon exhalation rate was therefore derived from the experimental measurement of alpha-track densities. The radon exhalation varied from (5.77 +/- 0.06) x 10(-5) to (7.61 +/- 0.07) x 10(-5) Bq cm(-2) h(-1) in bricks, from (5.79 +/- 0.05) x 10(-5) to (11.6 +/- 0.12) x 10(-5) in tiles, and was (6.95 +/- 0.03) x 10(-5) Bq cm(-2) h(-1) in concrete. A correlation (correlation coefficient approximately 0.8) was found between radium concentration measured with a HPGe detector and the radon exhalation rate obtained using nuclear track detectors.

  20. Preliminary results of calculations for heavy-water nuclear-power-plant reactors employing 235U, 233U, and 232Th as a fuel and meeting requirements of a nonproliferation of nuclear weapons

    NASA Astrophysics Data System (ADS)

    Ioffe, B. L.; Kochurov, B. P.

    2012-02-01

    A physical design is developed for a gas-cooled heavy-water nuclear reactor intended for a project of a nuclear power plant. As a fuel, the reactor would employ thorium with a small admixture of enriched uranium that contains not more than 20% of 235U. It operates in the open-cycle mode involving 233U production from thorium and its subsequent burnup. The reactor meets the conditions of a nonproliferation of nuclear weapons: the content of fissionable isotopes in uranium at all stages of the process, including the final one, is below the threshold for constructing an atomic bomb, the amount of product plutonium being extremely small.

  1. Preliminary results of calculations for heavy-water nuclear-power-plant reactors employing {sup 235}U, {sup 233}U, and {sup 232}Th as a fuel and meeting requirements of a nonproliferation of nuclear weapons

    SciTech Connect

    Ioffe, B. L.; Kochurov, B. P.

    2012-02-15

    A physical design is developed for a gas-cooled heavy-water nuclear reactor intended for a project of a nuclear power plant. As a fuel, the reactor would employ thorium with a small admixture of enriched uranium that contains not more than 20% of {sup 235}U. It operates in the open-cycle mode involving {sup 233}U production from thorium and its subsequent burnup. The reactor meets the conditions of a nonproliferation of nuclear weapons: the content of fissionable isotopes in uranium at all stages of the process, including the final one, is below the threshold for constructing an atomic bomb, the amount of product plutonium being extremely small.

  2. Ingestion dose from 238U, 232Th, 226Ra, 40K and 137Cs in cereals, pulses and drinking water to adult population in a high background radiation area, Odisha, India.

    PubMed

    Lenka, Pradyumna; Sahoo, S K; Mohapatra, S; Patra, A C; Dubey, J S; Vidyasagar, D; Tripathi, R M; Puranik, V D

    2013-03-01

    A natural high background radiation area is located in Chhatrapur, Odisha in the eastern part of India. The inhabitants of this area are exposed to external radiation levels higher than the global average background values, due to the presence of uranium, thorium and its decay products in the monazite sands bearing placer deposits in its beaches. The concentrations of (232)Th, (238)U, (226)Ra, (40)K and (137)Cs were determined in cereals (rice and wheat), pulses and drinking water consumed by the population residing around this region and the corresponding annual ingestion dose was calculated. The annual ingestion doses from cereals, pulses and drinking water varied in the range of 109.4-936.8, 10.2-307.5 and 0.5-2.8 µSv y(-1), respectively. The estimated total annual average effective dose due to the ingestion of these radionuclides in cereals, pulses and drinking water was 530 µSv y(-1). The ingestion dose from cereals was the highest mainly due to a high consumption rate. The highest contribution of dose was found to be from (226)Ra for cereals and drinking water and (40)K was the major dose contributor from the intake of pulses. The contribution of man-made radionuclide (137)Cs to the total dose was found to be minimum. (226)Ra was found to be the largest contributor to ingestion dose from all sources.

  3. Non-destructive determination of uranium, thorium and 40K in tobacco and their implication on radiation dose levels to the human body.

    PubMed

    Landsberger, S; Lara, R; Landsberger, S G

    2015-11-01

    The naturally occurring radionuclides of (235)U, (238)U and (232)Th and their daughter products are a potential major source of anthropogenic radiation to tobacco smokers. Often overlooked is the presence of (40)K in tobacco and its implication to radiation dose accumulation in the human body. In this study, these three radiation sources have been determined in four typical US cigarettes using neutron activation analysis (NAA). The NAA reactions of (238)U(n,γ)(239)U, (232)Th(n,γ)(233)Th and (41)K(n,γ)(42)K were used to determine (235)U, (238)U and (232)Th and (40)K, respectively. The activity of (238)U can easily be determined by epithermal NAA of the (238)U(n,γ)(239)U reaction, and the activity of (235, 234)U can easily be deduced. Using isotopic ratios, the activity due to (40)K was found by the determined concentrations of (41)K (also by epithermal neutrons) in the bulk material. Each gram of total potassium yields 30 Bq of (40)K. The annual effective dose for smokers using 20 cigarettes per day was calculate to be 14.6, 137 and 9 μSv y(-1) for (238,235,) (234)U, (232)Th and (40)K, respectively. These values are significantly lower that the dose received from (210)Po except for (232)Th.

  4. [Uptake of radionuclides from soil to plant and the discovery of 226Ra, 232Th hyperaccumulator].

    PubMed

    Zhang, Zhi-Qiang; Chen, Di-Yun; Song, Gang; Yue, Yu-Mei

    2011-04-01

    11 sorts of plant samples and corresponding soil samples were collected in Conghua and Taishan, Pearl River Delta. The specific activity of 238U, 226Ra, 232Th and 40K of samples were investigated by using HPGe-gamma-ray spectra analysis. The results showed that the average specific activity of 238U, 226Ra, 232Th and 40K in soil samples were 151.8, 146.3, 226.6, 665.5 Bq/kg, which were higher than the average values of China and the world. The concentration of 238U in all sort of plants are very low and most of them are lower than detection limit, while the values of 226Ra, 232Th and 40K were high. The contents of 226Ra and 232Th in Dicranopteris dichotoma were the highest, whose average specific activity is 285.9, 986.2 Bq/kg respectively. The average bioconcentration factors (BFs)of 26Ra, 232Th of Dicranopteris dichotoma were 2.20, 4.23, respectively, the other 10 sort of plants have BFs of 2266Ra, 232Th were in the range of 10(-1)-10(-2). The bioconcentration factors and the translocation factors of 226Ra, 232Th of Dicranopteris dichotoma. were all bigger than 1, so Dicranopteris dichotoma can be defined as hyperaccumulator of 226Ra and 232Th. PMID:21717763

  5. Prompt γ-rays from the Fast Neutron Induced Fission on 235,238U and 232Th

    NASA Astrophysics Data System (ADS)

    Lebois, M.; Wilson, J. N.; Halipré, P.; Leniau, B.; Matea, I.; Oberstedt, A.; Oberstedt, S.; Verney, D.

    Preliminary results from the first experiment using the LICORNE neutron source at the IPN Orsay are presented. Prompt fission gamma rays from fast-neutron induced fission of 238U, 232Th and 235U were detected. Thick samples of around 50 g of 238U and 232Th are used for the first part of the experiment. An ionisation chamber containing ∼ 10 mg samples of 238U and 235U to provide a fission trigger is used for the second part of the experiment. Gamma rays have been detected using 17 high efficiency BaF2 detectors and 6 LaBr3 scintillator detectors.

  6. 232Th, 233Pa, and 234U capture cross-section measurements in moderated neutron flux

    NASA Astrophysics Data System (ADS)

    Bringer, O.; Isnard, H.; AlMahamid, I.; Chartier, F.; Letourneau, A.

    2008-07-01

    The Th-U cycle was studied through the evolution of a 100 μg 232Th sample irradiated in a moderated neutron flux of 8.010 14 n/cm 2/s, intensity close to that of a thermal molten salt reactor. After 43 days of irradiation and 6 months of cooling, a precise mass spectrometric analysis, using both TIMS and MC-ICP-MS techniques, was performed, according to a rigorous methodology. The measured thorium and uranium isotopic ratios in the final irradiated sample were then compared with integral simulations based on evaluated data; an overall good agreement was seen. Four important thermal neutron-capture cross-sections were also extracted from the measurements, 232Th (7.34±0.21 b), 233Pa (38.34±1.78 b), 234U (106.12±3.34 b), and 235U (98.15±11.24 b). Our 232Th and 235U results confirmed existing values whereas the cross-sections of 233Pa and 234U (both key parameters) have been redefined.

  7. Fission cross sections of some thorium, uranium, neptunium and plutonium isotopes relative to /sup 235/U

    SciTech Connect

    Meadows, J W

    1983-10-01

    Earlier results from the measurements, at this Laboratory, of the fission cross sections of /sup 230/Th, /sup 232/Th, /sup 233/U, /sup 234/U, /sup 236/U, /sup 238/U, /sup 237/Np, /sup 239/Pu, /sup 240/Pu, and /sup 242/Pu relative to /sup 235/U are reviewed with revisions to include changes in data processing procedures, alpha half lives and thermal fission cross sections. Some new data have also been included. The current experimental methods and procedures and the sample assay methods are described in detail and the sources of error are presented in a systematic manner. 38 references.

  8. Discrete deexcitations in 235U from Nuclear Resonance Fluorescence

    NASA Astrophysics Data System (ADS)

    Kwan, E.; Howell, C. R.; Raut, R.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Adekola, A. S.; Hammond, S. L.; Karwowski, H. J.; Pedroni, R.; Kelley, J. H.

    2010-11-01

    Systematics of the even-even rare-earth nuclei suggest a concentration of M1 excitations peaking around 3 MeV with a ∑B(M1) strength of ˜3μN^2. In addition, a linear dependence on the square of the ground-state deformation was observed in the systematics of the ∑B(M1) strengths. The actinide region is interesting for investigation of the ``scissors'' mode of M1 excitations because it has neutron-rich nuclei with large deformations. Evidence of M1 resonances concentrated around 2.0-2.5 MeV were found in ^238U & ^232Th. A research program has been initiated at TUNL to measure dipole transitions in the actinide using HIγS. Nearly monoenergic & circular polarized γ-ray beams below 3.0 MeV was used to measure transitions in ^235U. More than 20 transitions were observed. The integrated cross sections, B(M1) strengths & branching transitions intensities will be presented and compared with previous measurements.

  9. Evaluation of 235U decay data.

    PubMed

    Xiaolong, Huang; Baosong, Wang

    2009-09-01

    Evaluation of the complete decay scheme and data for (235)U including new measurements are presented in this report; literature data available up to June 2008 are included. The half-life is determined to be (7.04+/-0.01) x 10(8) yr. All known measured gamma-ray absolute intensities have been examined; the gamma-ray emission probability of the reference gamma-ray line of 185.72 keV is recommended to be 57.0+/-0.3%. The calculated internal conversion coefficients and their uncertainties have been used to obtain the complete decay intensity balance. The other decay characteristics are calculated using the ENSDF analysis program. Finally the new decay scheme for (235)U is presented.

  10. Fission of 232Th in a spallation neutron field

    NASA Astrophysics Data System (ADS)

    Yurevich, V. I.; Nikolaev, V. A.; Yakovlev, R. M.

    2016-03-01

    The spatial distributions of thorium fission reaction rate in a spallation neutron field of thick lead target bombarded by protons or deuterons with energy between 1.0 and 3.7 GeV were measured. Approximately a linear dependence of the thorium fission rate on the beam energy is observed. The mean fission cross section of 232Th <σ f > ≈ 123 mb and it does not depend on energy and type of the beam particles.

  11. Correction methodology for the spectral interfering γ-rays overlapping to the analytical peaks used in the analysis of 232Th.

    PubMed

    Yücel, H; Köse, E; Esen, A N; Bor, D

    2011-06-01

    In the γ-ray spectrometric analysis of the radionuclides, a correction factor is generally required for the spectral interfering γ-rays in determining the net areas of the analytical peaks because some interfering γ-rays often might contribute to the analytical peaks of interest. In present study, a correction methodology for the spectral interfering γ-rays (CSI) is described. In particular, in the analysis of (232)Th contained in samples, the interfering γ-rays due to (226)Ra, (235)U, (238)U and their decay products often overlap to the peaks of interest from (232)Th decay products, and vise versa. For the validation of the proposed CSI method, several certified reference materials (CRM) containing U and Th were measured by using a 76.5% efficient n-type Ge detector. The required correction factors were quantified for spectral interference, self-absorption and true coincidence summing (TCS) effects for the relevant γ-rays. The measured results indicate that if one ignores the contributions of the interfering γ-rays to the analytical peaks at 583.2 keV of (208)Tl and 727.3 keV of (212)Bi, this leads to a significantly systematic influence on the resulted activities of (232)Th. The correction factors required for spectral interference and TCS effects are estimated to be ∼13.6% and ∼15.4% for 583.2 keV peak. For the 727.3 keV peak, the correction factor is estimated to be ∼15% for spectral interference, and ∼5% for the TCS effects at the presently used detection geometry. On the other hand, the measured results also indicate that ignoring the contribution of the interfering γ-rays to the areas of the analytical peaks at 860.6 keV of (208)Tl, 338.3 and 911.2 keV of (228)Ac does not lead to any significant systematic influence on the (232)Th analysis. Because these factors are remained generally less than ∼5%, i.e., within overall uncertainty limits. The present study also showed that in view of both the spectral interference and TCS effects, the

  12. 31 CFR 540.315 - Uranium-235 (U235).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Uranium-235 (U235). 540.315 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term uranium-235 or U235 means the...

  13. 31 CFR 540.315 - Uranium-235 (U235).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Uranium-235 (U235). 540.315 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term uranium-235 or U235 means the...

  14. 31 CFR 540.315 - Uranium-235 (U235).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Uranium-235 (U235). 540.315 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term uranium-235 or U235 means the...

  15. 31 CFR 540.315 - Uranium-235 (U235).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Uranium-235 (U235). 540.315 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term uranium-235 or U235 means the...

  16. 31 CFR 540.315 - Uranium-235 (U235).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Uranium-235 (U235). 540.315 Section... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY HIGHLY ENRICHED URANIUM (HEU) AGREEMENT ASSETS CONTROL REGULATIONS General Definitions § 540.315 Uranium-235 (U235). The term uranium-235 or U235 means the...

  17. First measurements on how pressure affects the half-life of 22Na: Comparison to theory and analog to 40K

    NASA Astrophysics Data System (ADS)

    Lee, K. K.; Nelson, R. O.; Rundberg, R.; Steinle-Neumann, G.

    2007-12-01

    Radioactive decay plays a central role in planetary sciences as appropriate decay schemes are used to date geological and astronomical processes and radioactivity provides an important source of heat in planetary bodies, both in their early history during accretion and differentiation and also over geological times. The most important isotopes that currently heat the Earth are 40K, 232Th, 235U and 238U. As radioactive decay is a nuclear process it is considered to be insensitive to external factors such as pressure or chemical environment. This has been shown to be true for α, β+ and β- processes, however, electron capture decay is dependent on the electron charge density at the nucleus of a compound, which is sensitive to the external environment. Using high-resolution Ge gamma-ray detectors to make relative measurements with 137Cs and the positron decay of 22Na, we measure how pressure affects the half-life of 22Na due to electron-capture decay. Our systematics look favorable for observing this small effect. We will compare our preliminary measurements with complementary ab-initio all-electron computations using the linearized augmented plane wave method (LAPW). Using 22Na as an analog for 40K, our results suggest that the pressure effect for 40K, combined with the opposing effects of high temperatures, will have little, discernible effect on the heat production in the deep Earth as our predicted changes are smaller than the uncertainties in the total decay constant for 40K. This work was supported in part by the Carnegie/DOE Alliance Center (CDAC), through the Stewardship Science Academic Alliances Program of the U.S. Department of Energy. The LANSCE facility is operated, and portions of this work were performed, by Los Alamos National Security, LLC, funded by the U.S. Department of Energy under Contract No. DE-AC52- 06NA25396.

  18. Natural fractionation of 238U/235U

    NASA Astrophysics Data System (ADS)

    Weyer, S.; Anbar, A. D.; Gerdes, A.; Gordon, G. W.; Algeo, T. J.; Boyle, E. A.

    2008-01-01

    The isotopic composition of U in nature is generally assumed to be invariant. Here, we report variations of the 238U/235U isotope ratio in natural samples (basalts, granites, seawater, corals, black shales, suboxic sediments, ferromanganese crusts/nodules and BIFs) of ∼1.3‰, exceeding by far the analytical precision of our method (≈0.06‰, 2SD). U isotopes were analyzed with MC-ICP-MS using a mixed 236U-233U isotopic tracer (double spike) to correct for isotope fractionation during sample purification and instrumental mass bias. The largest isotope variations found in our survey are between oxidized and reduced depositional environments, with seawater and suboxic sediments falling in between. Light U isotope compositions (relative to SRM-950a) were observed for manganese crusts from the Atlantic and Pacific oceans, which display δ238U of -0.54‰ to -0.62‰ and for three of four analyzed Banded Iron Formations, which have δ238U of -0.89‰, -0.72‰ and -0.70‰, respectively. High δ238U values are observed for black shales from the Black Sea (unit-I and unit-II) and three Kupferschiefer samples (Germany), which display δ238U of -0.06‰ to +0.43‰. Also, suboxic sediments have slightly elevated δ238U (-0.41‰ to -0.16‰) compared to seawater, which has δ238U of -0.41 ± 0.03‰. Granites define a range of δ238U between -0.20‰ and -0.46‰, but all analyzed basalts are identical within uncertainties and slightly lighter than seawater (δ238U = -0.29‰). Our findings imply that U isotope fractionation occurs in both oxic (manganese crusts) and suboxic to euxinic environments with opposite directions. In the first case, we hypothesize that this fractionation results from adsorption of U to ferromanganese oxides, as is the case for Mo and possibly Tl isotopes. In the second case, reduction of soluble UVI to insoluble UIV probably results in fractionation toward heavy U isotope compositions relative to seawater. These findings imply that variable

  19. Comparative study of different analytical methods for the determination of 238U, 234U, 235U, 230Th and 232Th in NORM samples (Southern Catalonia).

    PubMed

    Mola, M; Palomo, M; Peñalver, A; Borrull, F; Aguilar, C

    2013-01-01

    Uranium and thorium isotopes from sludge samples taken from an area of influence of a dicalcium phosphate factory, located close to the Ebro River reservoir in Flix, and from mineral raw materials (coal and phosphate) which were deposited in Tarragona Harbour (Catalonia) have been measured. To do that, several procedures to determine these isotopes have been applied and compared in terms of accuracy, precision and total analysis time. In particular, digestion procedures, such as one based on conventional acidic digestion or another based on the use of microwave digestion, have been tested. Moreover, different radiochemical separation procedures have been applied. In this regard, one method based on liquid-liquid extraction using TBP/Xylene and another based on the use of extraction chromatography using UTEVA resins have been compared. Firstly, the different proposed methods were tested by analyzing a phosphogypsum sediment and a moss-soil sample from two different intercomparison exercises. The microwave digestion - UTEVA method provided the best results (recoveries higher than 82% for uranium and thorium isotopes) and was then applied to the NORM samples. The obtained results showed that the higher uranium and thorium activities values were found in phosphate raw material and in the more superficial samples located in sludge sediments next to the dicalcium phosphate factory.

  20. Comparative study of different analytical methods for the determination of 238U, 234U, 235U, 230Th and 232Th in NORM samples (Southern Catalonia).

    PubMed

    Mola, M; Palomo, M; Peñalver, A; Borrull, F; Aguilar, C

    2013-01-01

    Uranium and thorium isotopes from sludge samples taken from an area of influence of a dicalcium phosphate factory, located close to the Ebro River reservoir in Flix, and from mineral raw materials (coal and phosphate) which were deposited in Tarragona Harbour (Catalonia) have been measured. To do that, several procedures to determine these isotopes have been applied and compared in terms of accuracy, precision and total analysis time. In particular, digestion procedures, such as one based on conventional acidic digestion or another based on the use of microwave digestion, have been tested. Moreover, different radiochemical separation procedures have been applied. In this regard, one method based on liquid-liquid extraction using TBP/Xylene and another based on the use of extraction chromatography using UTEVA resins have been compared. Firstly, the different proposed methods were tested by analyzing a phosphogypsum sediment and a moss-soil sample from two different intercomparison exercises. The microwave digestion - UTEVA method provided the best results (recoveries higher than 82% for uranium and thorium isotopes) and was then applied to the NORM samples. The obtained results showed that the higher uranium and thorium activities values were found in phosphate raw material and in the more superficial samples located in sludge sediments next to the dicalcium phosphate factory. PMID:22742771

  1. The applicability of MGA method for depleted and natural uranium isotopic analysis in the presence of actinides (232Th, 237Np, 233Pa and 241Am).

    PubMed

    Yücel, Haluk

    2007-11-01

    The multi-group analysis (MGA) method for the determination of uranium isotopic abundances in depleted uranium (DU) and natural uranium (NU) samples is applied in this study. A set of non-destructive gamma-ray measurements of DU and NU samples were performed using a planar Ge detector. The relative abundances of 235U and 238U isotopes were compared with the declared values of the standards. The relative abundance for 235U obtained by MGA for a "clean" DU or NU sample with a content of uranium>1wt% is determined with an accuracy of about +/-5%. However, when several actinides such as 232Th, 237Np, 233Pa and 241Am are present along with uranium isotopes simulating "dirty" DU or NU, it has been observed that MGA method gives erroneous results. The 235U abundance results for the samples were 6-25 times higher than the declared values in the presence of above-mentioned actinides, since MGA is utilized the X-ray and gamma-ray peaks in the 80-130 keV energy region, covering XKalpha and XKbeta regions. After the least-squares fitting of the spectra, it is found that the increases in the intensities of the X-ray and gamma-ray peaks of uranium are remarkably larger in the complex 80-130 keV region. On the other hand, it is observed that the interferences of the actinide peaks are relatively less dominant in the higher gamma-ray region of 130-300 keV. The results imply the need for dirty DU and NU samples that the MGA method should utilize the higher energy gamma-rays (up to 1001 keV of (234m)Pa) combined with lower energies of the spectra, which may be collected in a two detector mode (a planar Ge and a high efficient coaxial Ge).

  2. The applicability of MGA method for depleted and natural uranium isotopic analysis in the presence of actinides (232Th, 237Np, 233Pa and 241Am).

    PubMed

    Yücel, Haluk

    2007-11-01

    The multi-group analysis (MGA) method for the determination of uranium isotopic abundances in depleted uranium (DU) and natural uranium (NU) samples is applied in this study. A set of non-destructive gamma-ray measurements of DU and NU samples were performed using a planar Ge detector. The relative abundances of 235U and 238U isotopes were compared with the declared values of the standards. The relative abundance for 235U obtained by MGA for a "clean" DU or NU sample with a content of uranium>1wt% is determined with an accuracy of about +/-5%. However, when several actinides such as 232Th, 237Np, 233Pa and 241Am are present along with uranium isotopes simulating "dirty" DU or NU, it has been observed that MGA method gives erroneous results. The 235U abundance results for the samples were 6-25 times higher than the declared values in the presence of above-mentioned actinides, since MGA is utilized the X-ray and gamma-ray peaks in the 80-130 keV energy region, covering XKalpha and XKbeta regions. After the least-squares fitting of the spectra, it is found that the increases in the intensities of the X-ray and gamma-ray peaks of uranium are remarkably larger in the complex 80-130 keV region. On the other hand, it is observed that the interferences of the actinide peaks are relatively less dominant in the higher gamma-ray region of 130-300 keV. The results imply the need for dirty DU and NU samples that the MGA method should utilize the higher energy gamma-rays (up to 1001 keV of (234m)Pa) combined with lower energies of the spectra, which may be collected in a two detector mode (a planar Ge and a high efficient coaxial Ge). PMID:17606378

  3. Observations of 231Pa/ 235U disequilibrium in volcanic rocks

    NASA Astrophysics Data System (ADS)

    Pickett, David A.; Murrell, Michael T.

    1997-04-01

    We present here the first survey of ( 231Pa/ 235U) ratios in volcanic rocks; such measurements are made possible by new mass spectrometric techniques. The data place new constraints on the timing and extent of magma source and evolutionary processes, particularly due to the sensitivity of the 231Pa- 235U pair and its intermediate time scale ( 231Pat 1/2 = 33 ky). ( 231Pa/ 235U) is found to vary widely, from 0.2 in carbonatites to 1.1-2.9 in basalts and 0.9-2.2 in arcs. Substantial Pa enrichment is nearly ubiquitous, suggestive of the relative incompatibility of Pa, qualitatively consistent with available partitioning data. The level of 231Pa- 235U disequilibrium typically far exceeds that of 230Th- 238U and is comparable to 226Ra- 230Th. The high ( 231Pa/ 235U) ratios in MORB and other basalts reflect a large degree of discrimination between two incompatible elements, posing challenges for modelling of melt generation and migration. Fundamental differences in ( 231Pa/ 235U) among different basaltic environments are likely related to contrasts in melting zone conditions (e.g., melting rate). Strong ( 231Pa/ 235U) disequilibria in continental basalts, for which ( 230Th/ 238U) disequilibria are small or absent, demonstrate that Pa-U fractionation is possible in both garnet and spinel mantle stability fields. In arcs, correlation of ( 231Pa/ 235U) and ( 230Th/ 238U) is consistent with U enrichment via slab-derived fluids, a process which is additional to the still dominant Pa enrichment. An important new constraint is provided by the observation that the near-equilibrium ( 230Th/ 238U) common to arcs and continental basalts is not typically accompanied by near-equilibrium ( 231Pa/ 235U), arguing against the influence of long magma history, crustal material, or equilibrium mantle sources in affecting decay-series ratios. Small sample sets from two silicic centers illustrate: (1) recent, rapid U enrichment in the magma chamber (El Chichón); and (2) the failure of

  4. Nuclear excitation by electronic transition of 235U

    DOE PAGES

    Chodash, P. A.; Norman, E. B.; Burke, J. T.; Casperson, R. J.; Fisher, S. E.; Holliday, K. S.; Jeffries, J. R.; Wakeling, M. A.; Wilks, S. C.

    2016-03-11

    Here, nuclear excitation by electronic transition (NEET) is a rare nuclear excitation that can occur in isotopes containing a low-lying nuclear excited state. Over the past 40 yr, several experiments have attempted to measure NEET of 235U and those experiments have yielded conflicting results.

  5. Impact of the 235U Covariance Data in Benchmark Calculations

    SciTech Connect

    Leal, Luiz C; Mueller, Don; Arbanas, Goran; Wiarda, Dorothea; Derrien, Herve

    2008-01-01

    The error estimation for calculated quantities relies on nuclear data uncertainty information available in the basic nuclear data libraries such as the U.S. Evaluated Nuclear Data File (ENDF/B). The uncertainty files (covariance matrices) in the ENDF/B library are generally obtained from analysis of experimental data. In the resonance region, the computer code SAMMY is used for analyses of experimental data and generation of resonance parameters. In addition to resonance parameters evaluation, SAMMY also generates resonance parameter covariance matrices (RPCM). SAMMY uses the generalized least-squares formalism (Bayes method) together with the resonance formalism (R-matrix theory) for analysis of experimental data. Two approaches are available for creation of resonance-parameter covariance data. (1) During the data-evaluation process, SAMMY generates both a set of resonance parameters that fit the experimental data and the associated resonance-parameter covariance matrix. (2) For existing resonance-parameter evaluations for which no resonance-parameter covariance data are available, SAMMY can retroactively create a resonance-parameter covariance matrix. The retroactive method was used to generate covariance data for 235U. The resulting 235U covariance matrix was then used as input to the PUFF-IV code, which processed the covariance data into multigroup form, and to the TSUNAMI code, which calculated the uncertainty in the multiplication factor due to uncertainty in the experimental cross sections. The objective of this work is to demonstrate the use of the 235U covariance data in calculations of critical benchmark systems.

  6. Dating ivory by determination of 14C, 90Sr and 228/232Th.

    PubMed

    Schmied, Stefanie A K; Brunnermeier, Matthias J; Schupfner, Robert; Wolfbeis, Otto S

    2012-09-10

    A method is described to determine the time of death of elephants. This is accomplished by analysis of the radionuclides 14C, 90Sr and 228/232Th in known samples of ivory, and in samples of unknown age. The reliability of this method is considerably increased by multi nuclide analysis.

  7. sup 235 U accountability measurements on small samples

    SciTech Connect

    Sigg, R.A.

    1991-01-01

    Savannah River Site (SRS) is improving uranium accountability at its fuel fabrication facility through measurements of {sup 235}U in samples taken from uranium/aluminum alloy melts. Since area personnel desired a method that would minimize mixed waste, low volume samples are prepared from dissolutions of production melt grab samples. The solution assay monitor (SAM) analyzes for {sup 235}U gamm-rays by using a high-efficiency germanium well detector. The detector's high counting efficiency permits analysis of small samples (7 mL) from these dissolutions, and the counting geometry minimizes sample geometry uncertainties. Counting each sample for thirty minutes delivers excellent precision across the calibration range of 3 to 12 g uranium per liter. As shown by interlaboratory calibration, the gamma-ray spectrometer provides overall (counting, calibration, geometric,...) uncertainties less than 0.7% one sigma. Gamma-rays from a reference source, used to provide live-time corrections, are collimated to avoid absorption by the sample in the detector well. Since sample masses are small, minor self-attenuation corrections are calculated from chemical composition data rather than determined in separate transmission measurements. This avoids employing short-lived transmission sources for self-attenuation corrections.

  8. {sup 235}U accountability measurements on small samples

    SciTech Connect

    Sigg, R.A.

    1991-12-31

    Savannah River Site (SRS) is improving uranium accountability at its fuel fabrication facility through measurements of {sup 235}U in samples taken from uranium/aluminum alloy melts. Since area personnel desired a method that would minimize mixed waste, low volume samples are prepared from dissolutions of production melt grab samples. The solution assay monitor (SAM) analyzes for {sup 235}U gamm-rays by using a high-efficiency germanium well detector. The detector`s high counting efficiency permits analysis of small samples (7 mL) from these dissolutions, and the counting geometry minimizes sample geometry uncertainties. Counting each sample for thirty minutes delivers excellent precision across the calibration range of 3 to 12 g uranium per liter. As shown by interlaboratory calibration, the gamma-ray spectrometer provides overall (counting, calibration, geometric,...) uncertainties less than 0.7% one sigma. Gamma-rays from a reference source, used to provide live-time corrections, are collimated to avoid absorption by the sample in the detector well. Since sample masses are small, minor self-attenuation corrections are calculated from chemical composition data rather than determined in separate transmission measurements. This avoids employing short-lived transmission sources for self-attenuation corrections.

  9. Fission Product Decay Heat Calculations for Neutron Fission of 232Th

    NASA Astrophysics Data System (ADS)

    Son, P. N.; Hai, N. X.

    2016-06-01

    Precise information on the decay heat from fission products following times after a fission reaction is necessary for safety designs and operations of nuclear-power reactors, fuel storage, transport flasks, and for spent fuel management and processing. In this study, the timing distributions of fission products' concentrations and their integrated decay heat as function of time following a fast neutron fission reaction of 232Th were exactly calculated by the numerical method with using the DHP code.

  10. Charge distribution in the reactor-neutron-induced fission of 232Th

    NASA Astrophysics Data System (ADS)

    Erten, H. N.; Grütter, A.; Rössler, E.; von Gunten, H. R.

    1982-05-01

    The independent yields of 82Br, 86Rb, 96Nb, 98Nbm, 128Sbg, and 136Cs were determined in the reactor-neutron-induced fission of 232Th using radiochemical techniques. Results: (2.3+/-2.3)×10-4% for 82Br, <3.8×10-4% for 86Rb, <4.2×10-5% for 96Nb, (2.48+/-0.53)×10-3% for 98Nbm, (2.34+/-0.37)×10-3% for 128Sbg, and (1.70+/-0.13) ×10-4% for 136Cs. Using the extended Zp model of Wahl with the yield data from this work and the literature the following parameters were obtained for the charge distribution in 232Th fission: width of Gaussian dispersion σ¯Z=0.52+/-0.01, ΔZP (=ZP-ZUCD)=0.45+/-0.02. The even-odd proton and neutron enhancement factors were found to be small. These parameters and systematics of even-odd proton and neutron effects in low energy fission are discussed. NUCLEAR REACTIONS, FISSION Radiochemical fission yields 232Th(n,f), calculated charge dispersion parameters, and odd-even effects.

  11. Ultra Sensitive Neutron Activation Measurements of {sup 232}Th in Copper

    SciTech Connect

    Clemenza, M.; Previtali, E.; Borio di Tigliole, A.; Salvini, A.

    2011-04-27

    Copper, thanks to its low content in radioactive contaminations, is a material widely used for shielding, holders and other objects close to the sensitive parts of the detectors in many experiments in rare event physics. This implies that tools able to reach sensitivity of the order of <10{sup -12} gram of contaminants per gram of copper are of crucial importance. A methodology based in Neutron Activation Analysis (NAA) has been developed to obtain an extremely high sensitivity in the analysis of {sup 232}Th in copper samples. A detection limit of 5x10{sup -13} g {sup 232}Th/g Cu has been achieved through the irradiation of 200 g of copper sample which subsequently was radio-chemically concentrated using nitric acid and then actinide resin from Eichrom Inc. Several elutions were performed with various inorganic acids to concentrate the {sup 232}Th activation product ({sup 233}Pa) from the copper matrix and to also eliminate the radioactive background induced by the neutron bombardment to reach higher sensitivity.

  12. Measurement of 235U(n,n'γ) and 235U(n,2nγ) reaction cross sections

    NASA Astrophysics Data System (ADS)

    Kerveno, M.; Thiry, J. C.; Bacquias, A.; Borcea, C.; Dessagne, P.; Drohé, J. C.; Goriely, S.; Hilaire, S.; Jericha, E.; Karam, H.; Negret, A.; Pavlik, A.; Plompen, A. J. M.; Romain, P.; Rouki, C.; Rudolf, G.; Stanoiu, M.

    2013-02-01

    The design of generation IV nuclear reactors and the studies of new fuel cycles require knowledge of the cross sections of various nuclear reactions. Our research is focused on (n,xnγ) reactions occurring in these new reactors. The aim is to measure unknown cross sections and to reduce the uncertainty on present data for reactions and isotopes of interest for transmutation or advanced reactors. The present work studies the 235U(n,n'γ) and 235U(n,2nγ) reactions in the fast neutron energy domain (up to 20 MeV). The experiments were performed with the Geel electron linear accelerator GELINA, which delivers a pulsed white neutron beam. The time characteristics enable measuring neutron energies with the time-of-flight (TOF) technique. The neutron induced reactions [in this case inelastic scattering and (n,2n) reactions] are identified by on-line prompt γ spectroscopy with an experimental setup including four high-purity germanium (HPGe) detectors. A fission ionization chamber is used to monitor the incident neutron flux. The experimental setup and analysis methods are presented and the model calculations performed with the TALYS-1.2 code are discussed.

  13. Aspects Of The Coriolis Interaction In 235U

    SciTech Connect

    Ward, D.; Clark, R.M.; Cromaz, M.; Deleplanque, M.A.; Diamond, R.M.; Fallon, P.; Lee, I.Y.; Macchiavelli, A.O.; Stephens, F.S.; Lane, G.J.; Goergen, A.; Svensson, C.E.; Vetter, K.; Cline, D.; Hayes, A.B.; Teng, R.; Wu, C.-Y.; Nakatsukasa, T.

    2005-04-05

    We have performed three separate experiments at LBNL's 88-Inch Cyclotron over a period of several years in which 235U (thick target) was Coulomb-excited. It involved stand-alone experiments with Gammasphere and with the 8PI Spectrometer using 136Xe beams at 720 MeV, and a CHICO-Gammasphere experiment with an 40Ar beam at 180 MeV. In addition to extending the known negative-parity bands to high spin, we have assigned levels in some seven positive-parity bands which are in some cases ( e.g. [631]1/2, [624]7/2 and [622]5/2) strongly populated by E3 excitation. The CHICO data has been analyzed to extract E2 and E3 matrix elements from the observed yields. Additionally, many E1 and M1 matrix elements could be extracted from the {gamma}-ray branching ratios.

  14. [Mechanisms of 232Th effects on Chlorella vulgaris Beljer and modifications of it's toxic effect with caffeine and buthionine sulfoximine].

    PubMed

    Evseeva, T I; Maĭstrenko, T A; Geras'kin, S A; Belykh, E S

    2006-01-01

    232Th effects and its modifications with caffeine and D, L-buthionine-(S, R)-sulphoximine in Chlorella vulgaris Beijer cells was studied with use an optical density measure after 24 hours growth. Was shown relationship between concentration and toxic effect that is nonlinear and characterized with three parts different in induced damages level. In the first concentration range (0.001-1.551 micromol/l) chlorella growth parameters don't significantly differ from control ones. In the second one (1.724-3.017 micromol/1) statistically significant increase of optical density is but the effect does not dependent on 232Th concentration. The 232Th concentration (>3.448 micromol/l) increase the monotonous decrease in optical density was observed. The main role in 232Th toxic effect decrease make processes of DNA reparation, but not free radical scavenging with glutathione.

  15. Impact of the 235U series on doses from intakes of natural uranium and decay progeny.

    PubMed

    Lowe, L M

    1997-10-01

    The doses from 235U series radionuclides have often been ignored in dose assessments involving natural uranium and progeny. This is due to the relatively low abundance of 235U in natural uranium (less than 5% on an activity basis). However, inclusion of the 235U series radionuclides, especially 227Ac and 231Pa, in dose calculations can have a substantial impact on estimated inhalation doses.

  16. Impact of the 235U series on doses from intakes of natural uranium and decay progeny.

    PubMed

    Lowe, L M

    1997-10-01

    The doses from 235U series radionuclides have often been ignored in dose assessments involving natural uranium and progeny. This is due to the relatively low abundance of 235U in natural uranium (less than 5% on an activity basis). However, inclusion of the 235U series radionuclides, especially 227Ac and 231Pa, in dose calculations can have a substantial impact on estimated inhalation doses. PMID:9314233

  17. Identification of a shape isomer in 235U.

    PubMed

    Oberstedt, A; Oberstedt, S; Gawrys, M; Kornilov, N

    2007-07-27

    The shape isomer in 235U has been searched for in a neutron-induced fission experiment on 234U, which was performed at the isomer spectrometer NEPTUNE of the EC-JRC IRMM. A neutron source, with a tunable pulse frequency in the Hz to kHz range and its individually adjustable neutron pulse width in connection with an appropriate detector system turned out to be the ideal instrument to perform an isomer search, when decay half-lives above 100 micros are expected. From the delayed fission events observed for two different NEPTUNE settings and at mean incident neutron energies En=0.95 and 1.27 MeV the isomeric fission half-life could be determined to be T1/2=(3.6+/-1.8) ms. The corresponding cross section was determined to sigmaif=(10+/-8) microb. With these results an experimental confirmation for the existence of a superdeformed shape isomer in odd-uranium isotopes is given for the first time. PMID:17678355

  18. Determination of 235U/238U atom ratio in uranium samples using liquid scintillation counting (LSC).

    PubMed

    Alamelu, D; Aggarwal, S K

    2009-01-15

    A correlation has been developed for the determination of (235)U/(238)U atom ratio in uranium samples using liquid scintillation counting (LSC). The (235)U/(238)U atom ratio determined by thermal ionization mass spectrometry (TIMS) was correlated to the ratio of (i) alpha-count rate and (ii) Cerenkov count rate due to (234 m)Pa in the sample; both measured by LSC. This correlation is linear over the range of (235)U/(238)U atom ratio encountered in the nuclear fuel samples, i.e. the low enriched uranium (LEU) samples with (235)U<20 atom%. The methodology based on this correlation will be useful for the quick determination and verification of (235)U/(238)U atom ratios in fuel samples using cost effective technique of LSC. PMID:19064080

  19. Studies of positron electron pair production in {sup 238}U + {sup 232}Th

    SciTech Connect

    Ahmad, I.; Back, B.B.; Betts, R.R.

    1995-08-01

    Following the non-observation of sharp sum-energy lines in our earlier {sup 238}U + {sup 181}Ta measurements, it was decided to pursue measurements of the {sup 238}U + {sup 232}Th system which, in the previously published work, showed the most striking evidence for near-equal-energy back-to-back pairs leading to sharp sum-energy lines. Following the refurbishing of the APEX silicon arrays and extensive tests of the rotating target wheel assembly, a major positron run took place in November 1994. Rolled 1-mg/cm{sub 2} {sup 232}Th targets were bombarded with 5.95-MeV/u {sup 238}U. The target rotation allowed up to 2 pnA of beam to be used without serious deterioration of the targets. Over 300,000 pairs were accumulated, representing an order-of-magnitude improvement in statistics over the previously published results. Preliminary analysis shows no evidence for the sharp lines at a cross section level orders of magnitude below those previously reported. The analysis of these data is currently being completed in preparation for publication.

  20. Isotopic composition ( 238U/ 235U) of some commonly used uranium reference materials

    NASA Astrophysics Data System (ADS)

    Condon, Daniel J.; McLean, Noah; Noble, Stephen R.; Bowring, Samuel A.

    2010-12-01

    We have determined 238U/ 235U ratios for a suite of commonly used natural (CRM 112a, SRM 950a, and HU-1) and synthetic (IRMM 184 and CRM U500) uranium reference materials by thermal ionisation mass-spectrometry (TIMS) using the IRMM 3636 233U- 236U double spike to accurately correct for mass fractionation. Total uncertainty on the 238U/ 235U determinations is estimated to be <0.02% (2σ). These natural 238U/ 235U values are different from the widely used 'consensus' value (137.88), with each standard having lower 238U/ 235U values by up to 0.08%. The 238U/ 235U ratio determined for CRM U500 and IRMM 184 are within error of their certified values; however, the total uncertainty for CRM U500 is substantially reduced (from 0.1% to 0.02%). These reference materials are commonly used to assess mass-spectrometer performance and accuracy, calibrate isotope tracers employed in U, U-Th and U-Pb isotopic studies, and as a reference for terrestrial and meteoritic 238U/ 235U variations. These new 238U/ 235U values will thus provide greater accuracy and reduced uncertainty for a wide variety of isotopic determinations.

  1. Natural Isotopic Fractionation of 238U/235U in the Water Column of the Black Sea

    NASA Astrophysics Data System (ADS)

    Romaniello, S. J.; Brennecka, G.; Anbar, A. D.; Colman, A. S.

    2009-12-01

    The natural fractionation of long-lived uranium isotopes (238U, 235U) is being explored as a paleoredox proxy. While uranium behaves conservatively in oxic seawater, it is readily removed to sediments under reducing conditions. Measurements of δ238/235U in black shales and marine sediments deposited under sulfidic conditions suggest that uranium removed in such environments is isotopically heavy. However, this fractionation process has not been directly demonstrated in a present-day marine environment, nor is the specific mechanism of fractionation known. The euxinic water column of the Black Sea provides an ideal laboratory for studying uranium isotope fractionation. Uranium in Black Sea sediments is 0.35-0.84‰ heavy in δ238/235U relative to open ocean seawater (Weyer et al. 2008). We therefore expect that dissolved uranium in the Black Sea water column should be correspondingly light. Furthermore, direct measurements of δ238/235U versus depth could be used in combination with sediment δ238/235U to infer the dominant locations of U removal and constrain specific mechanisms of fractionation. Here we present the first δ238/235U depth profile from the water column of the Black Sea. The measurements were made on a Neptune MC-ICP-MS, using a 236U-233U double spike to correct for instrumental mass bias, following preconcentration and purification with UTEVA resin. With this method, we are able to measure δ238/235U with a 2σ precision of 0.07‰ on 100 ng samples. Our results show that δ238/235U decreases monotonically with depth (Fig. 1). At the surface, δ238/235U values are similar to those in the open ocean. At 2000m, δ238/235U is 0.28‰ lighter than open ocean seawater, while uranium concentrations are depleted by ~44% relative to conservative mixing. As expected, δ238/235U in the water column is always lighter than the underlying sediments, confirming that 238U is preferentially removed to marine sediments under sulfidic conditions. Fig 1. (left) Depth

  2. 232Th(n,{gamma})233Th Thermal Reaction Cross-Section Measurement

    SciTech Connect

    Maidana, Nora L.; Vanin, Vito R.; Pascholati, Paulo R.; Helene, Otaviano; Castro, Ruy M.; Dias, Mauro S.; Koskinas, Marina F.

    2005-05-24

    The 232Th(n,{gamma})233Th thermal neutron-capture reaction cross section was measured using targets of {approx} 1.5 mg of high-purity metallic thorium irradiated in the IPEN IEA-R1m 5 MW pool research reactor. The 197Au(n,{gamma})198Au reaction was used to monitor the thermal and epithermal neutron fluxes in the irradiation position, which was found using the Westcott formalism. The residual gamma-ray activity was followed with an HPGe detector. The detector efficiency curve was fitted by the least-squares method applying covariance analysis to all uncertainties involved. The experimental result is {sigma}0 =7.20{+-}0.20 b, in agreement with previous published values.

  3. Mass-resolved angular distribution of fission products in the 20Ne+232Th reaction

    NASA Astrophysics Data System (ADS)

    Tripathi, R.; Sodaye, S.; Sudarshan, K.; Guin, R.

    2013-08-01

    Mass-resolved angular distributions of fission product were measured in the 20Ne + 232Th reaction at Elab = 125.6 and 142.5 MeV using the recoil catcher technique followed by offline γ-ray spectrometry. Angular anisotropy was found to decrease with increasing asymmetry of mass division. Angular anisotropies of the fission products in the symmetric region were significantly higher compared to those calculated using the statistical saddle-point model. Experimental anisotropies could be explained after considering the contribution from pre-equilibrium fission. Use of barrier energies corresponding to different mass asymmetry values in the calculations could reasonably reproduce the mass dependence of angular anisotropies. The role of barrier energies in governing the angular anisotropy indicates that the mass dependence of anisotropy may possibly be a distinguishing feature of pre-equilibrium fission from quasifission, in which the composite system escapes into the exit channel without being captured inside the saddle point.

  4. Systematics of the mean energy and the mean multiplicity of prompt neutrons originating from {sup 232}Th fission

    SciTech Connect

    Svirin, M. I.

    2012-12-15

    The cross section for the neutron-induced fission of {sup 232}Th target nuclei, {sigma}{sub f} (E{sub n}), was described within statistical theory. The spectra of the mean multiplicity, v-bar (E{sub n}), and the mean energy, E-bar(E{sub n}), of secondary neutrons accompanying {sup 232}Th fission induced by neutrons of energy extending up to E{sub n} = 20 MeV were analyzed on the basis of the chance structure of the cross section.

  5. Using 232Th to monitor dissolved and total detrital inputs to the ocean

    NASA Astrophysics Data System (ADS)

    Robinson, L. F.; Noble, T. L.; McManus, J. F.

    2007-12-01

    This study uses long lived thorium isotopes as a tracer for both total and dissolved detrital inputs to seawater over time. Th-232 in seawater is derived exclusively from detritus, and its presence in the dissolved phase results from partial dissolution of this material. 230Th is produced in situ at a predictable rate by the decay of uranium, and its subsequent removal by efficient adsorption onto settling particles provides a method to quantify both dissolved and total 232Th fluxes to the seafloor. Assuming a fixed Th-232 concentration in detritus allows calculation of detrital fluxes to the seafloor. Sediments were acid leached to extract adsorbed Th, and Th associated with carbonate phases. Select samples were also subject to total dissolution. Adsorbed (and total) core top ratios giving high dissolved (and total) Th-232 fluxes were measured in sediment cores from locations with high expected detrital inputs and vice versa. The absolute values of these fluxes are reasonable by comparison to global estimates of detrital inputs to the ocean. Down core results display higher 232Th/230Th ratios that are consistent with enhanced ice-age dust deposition in the central Atlantic, North Pacific and a Southern Ocean transect. In general the glacial increases indicated by both total and dissolved thorium are smaller than the order of magnitude changes recorded in high latitude ice cores. This new tracer may be used to evaluate a variety of scenarios regarding the ocean and atmosphere of the past, including dust fertilization schemes that link variations in paleo-productivity with changes in atmospheric carbon dioxide and global climate. The half-lives of both thorium isotopes are long enough to allow us to use our approach on sediments that span several glacial-interglacial cycles.

  6. Determination of 235U/238U Ratio on Urine by ICP-MS

    SciTech Connect

    Collins, L; Gobaleza, A; Langston, R; Radev, R; Than, C; Wong, C; Wood-Zika, A

    2011-10-19

    LLNL Internal Dosimetry Program - The new procedure satisfies the requirement to determine {sup 235}U/{sup 238}U ratio in bioassay urine samples. MDA - The L{sub C} and MDA{sub 95} for {sup 235}U are well below the required detection limit of 0.00035 {mu}g/L. Turn around time - Analysis of 10 samples plus 2 QCs can be completed in one work day (8 hours).

  7. Measurement of fission products yields in the quasi-mono-energetic neutron-induced fission of 232Th

    NASA Astrophysics Data System (ADS)

    Naik, H.; Mukherji, Sadhana; Suryanarayana, S. V.; Jagadeesan, K. C.; Thakare, S. V.; Sharma, S. C.

    2016-08-01

    The cumulative yields of various fission products in the 232Th(n, f) reaction at average neutron energies of 5.42, 7.75, 9.35 and 12.53 MeV have been determined by using an off-line γ-ray spectrometric technique. The neutron beam was produced from the 7Li(p, n) reaction by using the proton energies of 7.8, 12, 16 and 20 MeV. The mass chain yields were obtained from the cumulative fission yields by using the charge distribution correction of medium energy fission. The fine structure in the mass yield distribution was interpreted from the point of nuclear structure effect. On the other hand, the higher yield around mass number 133-134 and 143-144 as well as their complementary products were explained based on the standard I and standard II asymmetric mode of fission. From the mass yield data, the average value of light mass (), heavy mass (), the average number of neutrons (< ν >) and the peak-to-valley (P / V) ratios at different neutron energies of present work and literature data were obtained in the 232Th(n, f) reaction. The different parameters of the mass yield distribution in the 232Th(n, f) reaction were compared with the similar data in the 232Th(γ, f) reaction at comparable excitation energy and a surprising difference was observed.

  8. High precision {sup 230}Th and {sup 232}Th in the Norwegian Sea and Denmark by thermal ionization mass spectrometry

    SciTech Connect

    Moran, S.B.; Hoff, J.A.; Edwards, R.L.

    1995-10-01

    Seawater samples (1-2 liters) were collected from the Norwegian Sea and Denmark Strait and analyzed for {sup 230}Th and {sup 232}Th using highly sensitive thermal ionization mass spectrometry (TIMS). Depth profiles of dissolved {sup 230}Th and {sup 232}Th are characterized by surface water minima (<1 fg/kg, <5 pg/kg), subsurface maxima (12 fg/kg, 134 pg/kg), and intermediate concentrations that progressively decrease toward the bottom ({approximately}5 fg/kg, {approximately}17 pg/kg), respectively. The lack of an increase in {sup 230}Th with depth is suggested to result from the short ventilation age of Norwegian Sea Deep Water combined with enhanced scavenging near the basin margins. The {sup 230}Th maximum is attributed to advection of high {sup 230}Th in the Arctic Intermediate Water, whereas the {sup 232}Th maximum may he related to a particulate source. The low dissolved {sup 230}Th and {sup 232}Th concentrations observed in the NADW formation regions implies a minor advective export of these long-lived Th tracers to the North Atlantic. 24 refs., 1 fig., 1 tab.

  9. sup 238 U- and sup 232 Th-series chronology of phonolite fractionation at Mount Erebus, Antarctica

    SciTech Connect

    Reagan, M.K. ); Volpe, A.M. ); Cashman, K.V. )

    1992-03-01

    Uranium, thorium, radium, and barium abundances and {sup 234}U/{sup 238}U and {sup 230}Th/{sup 232}Th isotopic ratios determined by thermal ionization mass spectrometry and ({sup 228}Th)/({sup 232}Th) activity ratios determined by alpha spectrometry are used to date anorthoclase growth and infer magma chamber residence times of phonolites erupted in 1984 and 1988 from Mount Erebus, Antarctica. The 1984 and 1988 glasses have slightly different ({sup 230}Th)/({sup 232}Th) ratios but both have a 10% excess of ({sup 230}Th) over ({sup 238}U) and equilibrium ({sup 228}Th) values. By comparing these data and Pb-isotopic data reported in SUN and HANSON (1975) to similar data for oceanic basalts, the duration of differentiation from basanite to phonolite is limited to less than 150,000 years. The anorthoclase separates have ({sup 230}Th)/({sup 238}U) ratios exceeding those of the associated glasses but have ({sup 230}Th)/({sup 232}Th) ratios like those of the glasses. Both glasses are depleted in {sup 226}Ra with respect to {sup 230}Th by about 25%, whereas associated anorthoclase separates have extreme excesses of {sup 226}Ra over {sup 230}Th and ({sup 228}Th)/({sup 232}Th) = 2.2. On a plot of ({sup 226}Ra)/Ba vs. ({sup 230}Th)/BA, the glass-anorthoclase pairs produce isochrons averaging 2,380 y, which represents the average age of anorthoclase growth in the shallow magma system at Erebus. The implied residence time of phonolite magmas in the shallow magma chamber system of Erebus is about 3,000 y. Final crystal growth occurred after intrusion into the convecting lava lake less than decades before eruption.

  10. Parity violation in {sup 232}Th neutron resonances above 250 eV

    SciTech Connect

    Sharapov, E. I.; Bowman, J. D.; Crawford, B. E.; Delheij, P. P. J.; Frankle, C. M.; Iinuma, M.; Knudson, J. N.; Lowie, L. Y.; Lynch, J. E.; Masaike, A.

    2000-02-01

    The analysis of parity nonconservation (PNC) measurements performed on {sup 232}Th by the TRIPLE Collaboration has been extended to include the neutron energy range of 250 to 1900 eV. Below 250 eV all ten statistically significant parity violations have the same sign. However, at higher energies PNC effects of both signs were observed in the transmission of longitudinally polarized neutrons through a thick thorium target. Although the limited experimental energy resolution precluded analysis in terms of the longitudinal asymmetry, parity violations were observed and the cross section differences for positive and negative neutron helicities were obtained. For comparison, a similar analysis was performed on the data below 250 eV, for which longitudinal asymmetries were obtained previously. For energies below 250 eV, the p-wave neutron strength functions for the J=1/2 and J=3/2 states were extracted: S{sub 1/2}{sup 1}=(1.68{+-}0.61)x10{sup -4} and S{sub 3/2}{sup 1}=(0.75{+-}0.18)x10{sup -4}. The data provide constraints on the properties of local doorway states proposed to explain the PNC sign effect in thorium. (c) 2000 The American Physical Society.

  11. Retardation of 238U and 232Th decay chain radionuclides in Long Island and Connecticut aquifers

    NASA Astrophysics Data System (ADS)

    Copenhaver, Sally A.; Krishnaswami, S.; Turekian, Karl K.; Epler, Nathan; Cochran, J. K.

    1993-02-01

    Knowledge of the ability of an aquifer to retard the groundwater transport of toxic or radioactive ions can be inferred from the analysis of groundwater for the radionuclides of the 238U- and 232Th-decay chains. Groundwaters of varying chemical composition were analyzed from wells in Long Island, New York, and Connecticut. Aquifer lithologies are arkose, quartz sandstone, granite, and glacial drift. Adsorption ( k1) and desorption ( k2) coefficients for Ra and Pb were calculated using 222Rn activity as a measure of the supply of other α-recoil nuclides. Laboratory tests of the validity of this assumption were made by measuring the flux of 224Ra and 222Rn from aquifer solids. The ratio k 1/k 2 is the distribution coefficient, K, which is effectively equal to R ƒ, the retardation factor. The average value of K for Ra is 6 × 10 2 in Long Island aquifers and 5 × 10 4 in Connecticut. The distribution coefficient for Pb is 10 4 in Long Island and 10 5 in Connecticut. Results from this and other studies reveal a strong dependence of retardation on pH, ƒ O 2, and ionic strength that tends to overwhelm any dependence of retardation on lithology.

  12. Fractionation of 238U/235U by reduction during low temperature uranium mineralisation processes

    NASA Astrophysics Data System (ADS)

    Murphy, Melissa J.; Stirling, Claudine H.; Kaltenbach, Angela; Turner, Simon P.; Schaefer, Bruce F.

    2014-02-01

    Investigations of ‘stable’ uranium isotope fractionation during low temperature, redox transformations may provide new insights into the usefulness of the 238U/235U isotope system as a tracer of palaeoredox processes. Sandstone-hosted uranium deposits accumulate at an oxidation/reduction interface within an aquifer from the low temperature reduction of soluble U(VI) complexes in groundwaters, forming insoluble U(IV) minerals. This setting provides an ideal environment in which to investigate the effects of redox transformations on 238U/235U fractionation. Here we present the first coupled measurements of 238U/235U isotopic compositions and U concentrations for groundwaters and mineralised sediment samples from the same redox system in the vicinity of the high-grade Pepegoona sandstone-hosted uranium deposit, Australia. The mineralised sediment samples display extremely variable 238U/235U ratios (herein expressed as δUCRM145238, the per-mil deviation from the international NBL standard CRM145). The majority of mineralised sediment samples have δUCRM145238 values between -1.30±0.05 and 0.55±0.12‰, spanning a ca. 2‰ range. However, one sample has an unusually light isotopic composition of -4.13±0.05‰, which suggests a total range of U isotopic variability of up to ca. 5‰, the largest variation found thus far in a single natural redox system. The 238U/235U isotopic signature of the mineralised sediments becomes progressively heavier (enriched in 238U) along the groundwater flow path. The groundwaters show a greater than 2‰ variation in their 238U/235U ratios, ranging from δUCRM145238 values of -2.39±0.07 to -0.71±0.05‰. The majority of the groundwater data exhibit a clear systematic relationship between 238U/235U isotopic composition and U concentration; samples with the lowest U concentrations have the lowest 238U/235U ratios. The preferential incorporation of 238U during reduction of U(VI) to U(IV) and precipitation of uranium minerals leaves

  13. U-Pb chronology of the Solar System's oldest solids with variable 238U/ 235U

    NASA Astrophysics Data System (ADS)

    Amelin, Yuri; Kaltenbach, Angela; Iizuka, Tsuyoshi; Stirling, Claudine H.; Ireland, Trevor R.; Petaev, Michail; Jacobsen, Stein B.

    2010-12-01

    Accurate determination of the absolute ages of the oldest Solar System objects — chondrules and Ca-Al-rich inclusions (CAIs), requires knowledge of their 238U/ 235U ratios. This ratio was assumed to be invariant in all U-Pb dating of meteorites so far, but the recent discovery of U isotope variations in CAIs (Brennecka et al., 2010a) shows that this assumption is invalid. We present the first combined high-precision U and Pb isotopic data for a CAI, and U isotopic data for chondrules and whole rock fractions of the Allende meteorite. The Pb-Pb isochron age of the CAI SJ101 is 4567.18 ± 0.50 Ma, calculated using the measured 238U/ 235U = 137.876 ± 0.043 (2σ), reported relative to 238U/ 235U = 137.837 of the CRM 145 standard. Our best current estimate of the average terrestrial value is: 238U/ 235U = 137.821 ± 0.014.The error in the age includes uncertainties in the Pb-Pb isochron intercept and in the 238U/ 235U ratio. Allende bulk rock and chondrules have 238U/ 235U = 137.747 ± 0.017 (2σ), distinctly lower than the CAI. The difference in the 238U/ 235U ratio of 0.129 ± 0.046 (2σ) between the CAI and chondrules and bulk meteorite increases the 207Pb- 206Pb age difference by ~ 1.4 Ma, and eliminates apparent disagreement between the CAI-chondrule formation time interval determinations with the U-Pb and extinct nuclide ( 26Al- 26Mg and 182Hf- 182W) data. We discuss standardisation of 238U/ 235U measurements for U-Pb geochronology and cosmochronology, elemental and isotopic fractionation induced by intensive acid leaching, ages of CAIs in the context of 238U/ 235U variability, and possible causes of U isotopic variations in CAIs and meteorites.

  14. Relative {sup 235}U(n,{gamma}) and (n,f) cross sections from {sup 235}U(d,p{gamma}) and (d,pf)

    SciTech Connect

    Allmond, J.M.; Bernstein, L.A.; Beausang, C.W.; Phair, L.; Bleuel, D.L.; Burke, J.T.; Escher, J.E.; Evans, K.E.; Goldblum, B.L.; Hatarik,, R.; Jeppesen, H.B.; Rasmussen, J.O.

    2009-01-01

    The internal surrogate ratio method allows for the determination of an unknown cross section, such as (n,{gamma}), relative to a better-known cross section, such as (n,f), by measuring the relative exit-channel probabilities of a surrogate reaction that proceeds through the same compound nucleus. The validity of the internal surrogate ratio method is tested by comparing the relative gamma and fission exit-channel probabilities of a {sup 236}U* compound nucleus, formed in the {sup 235}U(d,p) reaction, to the known {sup 235}U(n,{gamma}) and (n,f) cross sections. A model-independent method for measuring the gamma-channel yield is presented and used.

  15. Study of 232Th(n, γ) and 232Th(n,f) reaction rates in a graphite moderated spallation neutron field produced by 1.6 GeV deuterons on lead target

    NASA Astrophysics Data System (ADS)

    Asquith, N. L.; Hashemi-Nezhad, S. R.; Westmeier, W.; Zhuk, I.; Tyutyunnikov, S.; Adam, J.

    2015-02-01

    The Gamma-3 assembly of the Joint Institute for Nuclear Research (JINR), Dubna, Russia is designed to emulate the neutron spectrum of a thermal Accelerator Driven System (ADS). It consists of a lead spallation target surrounded by reactor grade graphite. The target was irradiated with 1.6 GeV deuterons from the Nuclotron accelerator and the neutron capture and fission rate of 232Th in several locations within the assembly were experimentally measured. 232Th is a proposed fuel for envisaged Accelerator Driven Systems and these two reactions are fundamental to the performance and feasibility of 232Th in an ADS. The irradiation of the Gamma-3 assembly was also simulated using MCNPX 2.7 with the INCL4 intra-nuclear cascade and ABLA fission/evaporation models. Good agreement between the experimentally measured and calculated reaction rates was found. This serves as a good validation for the computational models and cross section data used to simulate neutron production and transport of spallation neutrons within a thermal ADS.

  16. Isotope ratios of (235)U/(238)U and (137)Cs/(235)U in black rain streaks on plaster wall caused by fallout of the Hiroshima atomic bomb.

    PubMed

    Shizuma, Kiyoshi; Endo, Satoru; Fujikawa, Yoko

    2012-02-01

    Radiological investigations of fallout from the atomic bomb detonated over Hiroshima city on 6 August 1945 are important to estimate doses for inhabitants. The authors have analyzed the concentrations of (137)Cs, (235)U, and (238)U in streaks of black rain caused by the atomic bomb using gamma-ray spectroscopy and the ICP-QMS method. The black rain streaks were deposited on a plaster wall of a house located 3.7 km west of the hypocenter that has been kept in the same condition as after the rainfall. Cesium-137 ((137)Cs) was detected from black streak samples. Concentration of (137)Cs in the black rain streaks is twice as high as fallout deposition on the ground in this area. A (235)U/(238)U atom ratio of 0.00887 was found, which is higher than the natural ratio, reflecting the fact that the atomic bomb "Little Boy" used enriched uranium as fuel. The ratio (137)Cs/(235)U was determined to be 0.0091, which is about eight times higher than the estimated ratio of 0.00113 based on the fission yield.

  17. Evaluating 238U/235U in U-bearing accessory minerals

    NASA Astrophysics Data System (ADS)

    Hiess, J.; Condon, D. J.; Noble, S. R.; McLean, N.; Bowring, S. A.; Mattinson, J. M.

    2010-12-01

    U-daughter (U-Pb, Pb-Pb, and U-series) geochronology and cosmochronology utilize the absolute value of the present day 238U/235U ratio to calculate and compare dates. For decades, this value has been assumed to be invariant and equal to 137.88, but recent experiments indicate that there is potential for ‘per mil level’ variation in 238U/235U in natural materials, hypothesized to be the result of redox reactions. These studies have largely focused on materials formed in low-temperature environments (e.g. speleothems, corals) and U ore deposits. At present there are no published high-precision high-accuracy 238U/235U data for U-bearing accessory minerals commonly used for U-Pb geochronology. We present accurate and precise 238U/235U determinations for a suite of common U-bearing accessory minerals (zircon, monazite etc.), from a variety of geological environments and ages. Measurements have been made by thermal ionization mass spectrometry, accurately correcting for mass fractionation using the IRMM 3636 233U-236U double spike. Accessory mineral 238U/235U ratios are generally lower than the ‘consensus’ value of 137.88. Systematic discordance has been observed in 238U/206Pb and 235U/207Pb dates obtained for closed-system minerals, and has been used to reassess the relative decay constants of 238U and 235U (Mattinson, 2000, 2010; Schoene et al., 2006). However, these attempts assumed values (i.e., 137.88 or 137.80) for all present-day 238U/235U ratios. Our new determination of coupled 238U/206Pb, 235U/207Pb and 238U/235U measurements on the same closed system zircons, all traceable to SI units, permit further refinement of λ238U/λ235U estimates. Mattinson J.M. 2000. Revising the "gold standard" - the Uranium decay constants of Jaffey et al., 1971. EOS, AGU Fall meeting Supplement Abstract V61A-02. Mattinson J.M. 2010. Analysis of the relative decay constants of 235U and 238U by multi-step CA-TIMS measurements of closed-system natural zircon samples. Chemical

  18. Development of a method for activity measurements of 232Th daughters with a multidetector gamma-ray coincidence spectrometer.

    PubMed

    Antovic, N; Svrkota, N

    2009-06-01

    The method for activity measurements of the (232)Th daughters, developed at the six-crystal gamma-ray coincidence spectrometer PRIPYAT-2M and based on coincidence counting of the 583 and 2615 keV photons from cascade transitions which follow beta(-)-decay of (208)Tl, as well as on counting the 911 keV photons which follow beta(-)-decay of (228)Ac in the integral and non-coincidence mode of counting, is presented.

  19. Development of a method for activity measurements of 232Th daughters with a multidetector gamma-ray coincidence spectrometer.

    PubMed

    Antovic, N; Svrkota, N

    2009-06-01

    The method for activity measurements of the (232)Th daughters, developed at the six-crystal gamma-ray coincidence spectrometer PRIPYAT-2M and based on coincidence counting of the 583 and 2615 keV photons from cascade transitions which follow beta(-)-decay of (208)Tl, as well as on counting the 911 keV photons which follow beta(-)-decay of (228)Ac in the integral and non-coincidence mode of counting, is presented. PMID:19299155

  20. Verification of 235U mass content in nuclear fuel plates by an absolute method

    NASA Astrophysics Data System (ADS)

    El-Gammal, W.

    2007-01-01

    Nuclear Safeguards is referred to a verification System by which a State can control all nuclear materials (NM) and nuclear activities under its authority. An effective and efficient Safeguards System must include a system of measurements with capabilities sufficient to verify such NM. Measurements of NM using absolute methods could eliminate the dependency on NM Standards, which are necessary for other relative or semi-absolute methods. In this work, an absolute method has been investigated to verify the 235U mass content in nuclear fuel plates of Material Testing Reactor (MTR) type. The most intense gamma-ray signature at 185.7 keV emitted after α-decay of the 235U nuclei was employed in the method. The measuring system (an HPGe-spectrometer) was mathematically calibrated for efficiency using the general Monte Carlo transport code MCNP-4B. The calibration results and the measured net count rate were used to estimate the 235U mass content in fuel plates at different detector-to-fuel plate distances. Two sets of fuel plates, containing natural and low enriched uranium, were measured at the Fuel Fabrication Facility. Average accuracies for the estimated 235U masses of about 2.62% and 0.3% are obtained for the fuel plates containing natural and low enriched uranium; respectively, with a precision of about 3%.

  1. Spatial and Temporal Distribution of Initial 230TH/232TH in Sumatran Corals and its Influence on the Accurate Dating of Young Corals

    NASA Astrophysics Data System (ADS)

    Chiang, H.; Shen, C.; Meltzner, A. J.; Philibosian, B.; WU, C.; Sieh, K. E.; Wang, X.

    2012-12-01

    Accurate and precise determination of initial 230Th/232Th (230Th/232Th0) is important in dating young fossil corals, and it can significantly influence our understanding of paleoclimate, paleoceanographic and paleoseismic histories. A total of 47 unpublished and published isochrons (Shen et al., 2008; Meltzner et al., 2010, 2012; Philibosian et al., 2012), covering most of the Sumatran outer-arc islands, provide a more robust estimate of the 230Th/232Th0 variability in the region. The weighted average of 230Th/232Th0 atomic values is 4.7 (+5.5/-4.7) × 10-6 (2σ), consistent with the previously reported value of 6.5 ± 6.5 × 10-6 obtained from a handful of samples from the southern part of Sumatran outer-arc. Specifically, the calculated 230Th/232Th0 in the north and south are identical. The weighted mean of 3.5 (+7.0/-3.5) × 10-6 for fossil corals of 300-2000-yr old is slightly lower than the value of 5.4 ± 4.5 × 10-6 obtained from corals younger than 300 yrs B.P.. For corals containing less than 2 ppb of thorium, however, the age offset will be less than 10 yr by using different 230Th/232Th0, which is acceptable for most studies. We hereby recommend an updated 230Th/232Th0 value of 4.7 (+5.5/-4.7) × 10-6 for corals throughout the Sumatran outer-arc islands. For very high-precision age determination (<10 yr), coral samples with low Th concentration (< 2 ppb) are preferred.; ;

  2. Differential Die-Away Analysis for detection of 235U in metallic matrix

    NASA Astrophysics Data System (ADS)

    Kashyap, Yogesh; Agrawal, Ashish; Roy, Tushar; Sarkar, P. S.; Shukla, Mayank; Patel, Tarun; Sinha, Amar

    2016-01-01

    Differential Die-Away Analysis is a powerful tool for detecting small quantity of fissile material even if it is shielded or placed in non-fissile matrix. The technique can be used to monitor and characterize fissile content for nuclear waste assay. In this paper, we have discussed the application of differential die away technique for detection of small quantity of fissile material in nuclear waste assay. Feasibility experiments to optimize various parameters have been carried out for detection of 235U in metallic matrix and reported in this paper. A minimum quantity of 1 g of 235U in 150 kg of metallic matrix has been detected in the experimental configuration being reported.

  3. Fissile Nuclei Rotation Effect in 235U(n,γf) Process

    NASA Astrophysics Data System (ADS)

    Danilyan, Gevorg; Granz, Peter; Klenke, Jens; Krakhotin, Vyacheslav; Kuznetsov, Valery; Mezei, Ferenz; Novitsky, Vadim; Pavlov, Valery; Russina, Margarita; Shatalov, Pavel; Wilpert, Thomas

    2009-01-01

    A small shift of an angular distribution of prompt γ-rays relative to the fission axis of 236U* 235U(n,γf) process is presented. This effect has been observed in the experiment at BER-II reactor of BENSC/HMI (Berlin). The sign of the shift depends on the direction of the incident neutron beam polarization. This phenomena can be explained by the rotation of fissile nucleus 236U*, like the effect that has been observed recently at ILL in ternary fission of 235U by cold polarized neutrons. The main surprise of this result is the detection of scission gamma-rays radiated by a fissile nucleus during the time interval of the order of 10-21 s before or after the moment of the neck rupture. Detailed measurements of trigger γ-rays energy dependence are in progress at the neutron beam "MEPHISTO" of FRM-II reactor (Garching).

  4. The 235U Prompt Fission Neutron Spectrum in the BR1 Reactor at SCK•CEN

    NASA Astrophysics Data System (ADS)

    Wagemans, Jan; Malambu, Edouard; Borms, Luc; Fiorito, Luca

    2016-02-01

    The BR1 research reactor at SCK•CEN has a spherical cavity in the graphite above the reactor core. In this cavity an accurately characterised Maxwellian thermal neutron field is present. Different converters can be loaded in the cavity in order to obtain other types of neutron (and gamma) irradiation fields. Inside the so-called MARK III converter a fast 235U(n,f) prompt fission neutron field can be obtained. With the support of MCNP calculations, irradiations in MARK III can be directly related to the pure 235U(n,f) prompt fission neutron spectrum. For this purpose MARK III spectrum averaged cross sections for the most relevant fluence dosimetry reactions have been determined. A calibration factor for absolute measurements has been determined applying activation dosimetry following ISO/IEC 17025 standards.

  5. Critical mass experiment using {sup 235}U foil-SiO{sub 2}-polyethylene plates

    SciTech Connect

    Sanchez, R.; Kimpland, R.; Butterfield, K.; Jaegers, P.; Casson, W.

    1998-12-31

    Fissile material in waste is frequently encountered in decontamination and decommissioning activities. Thousands of drums containing radioactive waste are stored in storage facilities throughout the US Department of Energy (DOE) complex. The amount of fissile material in each drum is generally small because of the criticality safety limits that have been calculated using neutron transport computer codes such as MCNP, KENO, or ONEDANT. No experimental critical data are available to ensure the correctness of the calculations for those systems containing fissile material ({sup 235}U, {sup 233}U, and {sup 239}Pu) in contact with matrix material (Al{sub 2}O{sub 3}, CaO, MgO, and SiO{sub 2}) in the drums. The purpose of the {sup 235}U foil-SiO{sub 2}-polyethylene experiment is to provide experimental data to validate the computer transport codes and the cross-section data.

  6. Calculation and measurement of 235U and 238U fussion counter assembly detection efficiency

    NASA Astrophysics Data System (ADS)

    Swinhoe, M. T.; Jarvis, O. N.

    1984-04-01

    The detection efficiencies of two fission counter assemblies ( 235U and 238U) designed to measure the neutron flux at JET, have been determined for monoenergetic and radioactive neutron sources. The results are in good agreement with calculations using Monte Carlo neutron transport codes, when care is used in setting up the computer models. The mean difference between calculation and experiment is (7±7%).

  7. Resonance analysis and evaluation of the sup 235 U neutron induced cross sections

    SciTech Connect

    Leal, L.C.

    1990-06-01

    Neutron cross sections of fissile nuclei are of considerable interest for the understanding of parameters such as resonance absorption, resonance escape probability, resonance self-shielding,and the dependence of the reactivity on temperature. In the present study, new techniques for the evaluation of the {sup 235}U neutron cross sections are described. The Reich-Moore formalism of the Bayesian computer code SAMMY was used to perform consistent R-matrix multilevel analyses of the selected neutron cross-section data. The {Delta}{sub 3}-statistics of Dyson and Mehta, along with high-resolution data and the spin-separated fission cross-section data, have provided the possibility of developing a new methodology for the analysis and evaluation of neutron-nucleus cross sections. The results of the analysis consists of a set of resonance parameters which describe the {sup 235}U neutron cross sections up to 500 eV. The set of resonance parameters obtained through a R-matrix analysis are expected to satisfy statistical properties which lead to information on the nuclear structure. The resonance parameters were tested and showed good agreement with the theory. It is expected that the parametrization of the {sub 235}U neutron cross sections obtained in this dissertation represents the current state of art in data as well as in theory and, therefore, can be of direct use in reactor calculations. 44 refs., 21 figs., 8 tabs.

  8. Isotope fractionation of 238U and 235U during biologically-mediated uranium reduction

    NASA Astrophysics Data System (ADS)

    Stirling, Claudine H.; Andersen, Morten B.; Warthmann, Rolf; Halliday, Alex N.

    2015-08-01

    A series of laboratory-controlled microbial experiments using gram-negative sulphate-reducing bacteria (Desulfovibrio brasiliensis) inoculated with natural uranium were performed to investigate 238U/235U fractionation during bacterially-mediated U reduction. Control experiments, without bacteria to drive U reduction, were conducted in parallel. Paired measurements of 238U/235U and U concentration for both the residual growth medium solution and the accumulated biologically-mediated precipitate were obtained using multiple-collector inductively coupled plasma mass spectrometry (MC-ICPMS). The control experiments show that only minor (<0.1‰), if any 238U/235U fractionation occurs during co-precipitation with calcite. This implies that carbonate sediments are capable of faithfully recording the signature of the global ocean during Earth's major climatic events, including oxygenation and de-oxygenation transitions in the marine environment. The results for the microbial experiments demonstrate that the 238U/235U composition of the unreacted growth medium containing U(VI) is isotopically lighter than the composition of the U(IV)-bearing precipitate as U(VI) is consumed, in agreement with field-based observations of microbially-mediated U reduction. Uranium isotopic shifts of up to 0.8‰ were observed between the liquid and solid phases. These observations can be modelled using a Rayleigh distillation approach describing kinetic uptake in a closed system, which yields a fractionation factor α of 0.99923 ± 0.00004 (ε = -0.77 ± 04‰) for U(VI)-U(IV) reduction mediated by the D. brasiliensis microbe. This fractionation behaviour is consistent with that observed in field-based redox environments, which give rise to similar α values. Competing processes such as U co-precipitation (e.g. adsorption) may act to lower the apparent value for α and possibly play a secondary role both in the microbial experiments of this study and in natural U reduction settings where

  9. Investigation of Nuclear Ground State Properties of Fuel Materials of 232Th and 238U Using Skyrme-Extended-Thomas-Fermi Approach Method

    NASA Astrophysics Data System (ADS)

    Yulianto, Yacobus; Su'ud, Zaki

    2016-08-01

    It has been performed the nuclear ground state properties investigation of 232Th and 238U using Skyrme interaction. The local density, the kinetic energy density, and the spin-orbit density for proton and neutron have been calculated using Extended-Thomas-Fermi approach method. Then the calculation results have been compared with Skyrme-Hartree-Fock results (using HAFOMN and HFBRAD codes). Total energy calculations obtained from this research are -1792.973947 MeV (for 232Th) deviated 0.29244% from experiment energy and -1761.519459 MeV (for 238U) deviated 0.48369% from experiment energy. The distribution profiles of local density and local potential for 232Th and 238U are quite similar with Skyrme- Hartree-Fock results. It is indicated that Skyrme-Extended-Thomas-Fermi method can be used to study the nuclear ground state properties, especially even nuclei.

  10. Sensitivity of large-scale neutrino detector to 40K geoneutrinos

    NASA Astrophysics Data System (ADS)

    Ungar, Yocheved

    2015-10-01

    Uranium, Thorium and Potassium are the primary radioactive constituents of Earth's mantle and crust. Neutrinos released during the decay of these radioactive elements can be used to directly study the bulk composition of Earth's interior. While existing detectors such as a KamLand and Borexino have detected 232Th and 238U, they do not have the sensitivity to observe the low energy (<1.8 MeV) 40K geoneutrinos. 40K geoneutrinos have been predicted to be the most abundant of the radioactive elements in Earth's interior and therefore are of particular interest. I am studying the feasibility of using a large scale (1000 ton) scintillator based detector to search for 40K geoneutrinos that interact with the scintillator through the process of antineutrino-electron scattering. I will present the results of calculations of neutrino flux predictions and the expected number of scattering events in a kiloton-scale detector as well as studies of backgrounds and their effect on the viability of detecting 40K geoneutrinos.

  11. Mass dependence of fragment angular distributions in the fission of 232Th and 236U induced by polarized photons

    NASA Astrophysics Data System (ADS)

    Steiper, F.; Frommhold, Th.; Henkel, W.; Jung, A.; Kneissl, U.; Stock, R.

    1993-10-01

    Near-barrier fission of 232Th and 236U induced by linearly polarized photons has been investigated. The experiments have been carried out at the "off-axis" bremsstrahlung facility of the Giessen 65 MeV electron linac. Fragment angular, mass and energy distributions have been measured simultaneously allowing the investigation of correlations between these fragment characteristics. A consistent assignment of the quantum numbers Jπ and K for the fussion channels involved in the fission process is proposed. For the first time, the polar anisotropies and azimuthal asymmetries of the fission fragment angular distributions W( θ, φ) have been investigated as a function of the fragment masses. The results are discussed in the framework of the double-humped fission barrier concept and the so-called "multi-exit fission channel" model. Additionally, angular distributions of heavy and light fission fragments from photofission of 236U have been analyzed for a possible asymmetry with respect to θ = 90°.

  12. Gamma-ray spectrometer measurement of 238U/235U in uranium ore from a natural reactor at Oklo, Gabon

    USGS Publications Warehouse

    Moxham, Robert M.

    1976-01-01

    About 20 years ago, Kuroda theorized that a high-grade uranium deposit emplaced about 2x109 years ago could achieve criticality and sustain a nuclear chain reaction, given a sufficient thickness of high-grade ore and an appropriate water content. Such a natural reactor was found in 1972 at the Oklo deposit, Gabon. The ore contains as much as 60 percent uranium, but the isotopic abundance of 235U is as little as 0.4 percent in contrast to the normal abundance of 0.7110 percent 235U. A sample from the Oklo deposit containing about 0.51 atom percent 235U (by mass spectrometer) was analyzed by a gamma-ray spectrometer system, using a high-purity planar germanium detector. The 235U was determined from its daughter's (234Th) 63.3 keV photopeak; the 235U was determined from its 143.8 and 163.4 keV photopeaks. The ratios of these photopeaks were compared with that from a standard having normal uranium isotopic content; the resulting calculations give a 235U abundance of 0.54 atom percent in the Oklo sample. The gamma-ray spectrum also contains lines from five other isotopes in the uranium series, which indicate the Oklo sample to be at or near secular equilibrium, as the time elapsed since the nuclear reaction ended was sufficient to permit the daughters to achieve equilibrium.

  13. New chronometers for the metamorphism of ophiolitic rocks: 40Ar/39Ar neptunite and 232Th/208Pb joaquinite

    NASA Astrophysics Data System (ADS)

    Borneman, N.; Hodges, K. V.; Van Soest, M. C.

    2015-12-01

    Both primary magmatism and metamorphism of ophiolite sequences are difficult to date, due in large part to the fact that the majority of lithologies present tend to contain very low concentrations of radioactive elements. As a result, researchers are often forced to process large amounts of material to search for accessory phases like zircons in gabbro, or to employ geochronometers that often yield multiply interpretable results (e.g., 40Ar/39Ar glaucophane or phengite), or to rely on indirect evidence for inferring ages. Here, we introduce two new options for chronometery of metamorphosed ophiolites: 40Ar/39Ar neptunite and 232Th/208Pb joaquinite. The best known locality for these rare minerals is the New Idria serpentinite diapir, found within the southern Diablo Range of the Coast Range Province of California. Here, both the joaquinite and neptunite chronometers record indistinguishable dates that we interpret to be the crystallization age of the phases during diapir ascent, based on the demonstrated low temperature history of the diapir as whole and the agreement of dates from chromonometers that almost certainly have different closure temperatures. This age is generally inferred to be coincident with the timing of the passage of the Mendocino Triple Junction and associated initiation of the San Andreas fault in this area. We propose that the mean40Ar/39Ar neptunite plateau date of 12.375 ± 0.082 Ma and corroborating 232Th/208Pb joaquinite date (12.08 ± 0.59 Ma) may represent a high-precision constraint on the timing of this event. We also report a second application of these chronometers to samples from the Yarlung suture, which formed at the time of initial India-Eurasia collision in southern Tibet. Here, both chronometers record indistinguishable dates of ca. 52 Ma, which we also interpret as the crystallization age. This age is consistent with most previously published estimates for the timing of the India-Eurasia collision.

  14. Fission yields of In isotopes in the thermal neutron fission of235U

    NASA Astrophysics Data System (ADS)

    Shmid, M.; Engler, G.

    1983-03-01

    Fission yields of124 132In in the thermal neutron fission of235U were determined for the first time. Charge displacements ΔZ= Z p- Z UCD were calculated for the corresponding mass chains. Both fission yields and charge displacement values were compared with those obtained by systematics by Wahl et al. and Wolfsberg. It was found that the fission yields of the In isotopes obey the gaussian distribution. The displacement function of Wolfsberg seems to give the better representation of the experimental results. Half-lives of124 131In were determined from beta decay curves.

  15. Moderation control in low enriched {sup 235}U uranium hexafluoride packaging operations and transportation

    SciTech Connect

    Dyer, R.H.; Kovac, F.M.; Pryor, W.A.

    1993-12-31

    Moderation control is the basic parameter for ensuring nuclear criticality safety during the packaging and transport of low {sup 235}U enriched uranium hexafluoride before its conversion to nuclear power reactor fuel. Moderation control has permitted the shipment of bulk quantities in large cylinders instead of in many smaller cylinders and, therefore, has resulted in economies without compromising safety. Overall safety and uranium accountability have been enhanced through the use of the moderation control. This paper discusses moderation control and the operating procedures to ensure that moderation control is maintained during packaging operations and transportation.

  16. Moderation control in low enriched {sup 235}U uranium hexafluoride packaging operations and transportation

    SciTech Connect

    Dyer, R.H.; Kovac, F.M.; Pryor, W.A.

    1993-10-01

    Moderation control is the basic parameter for ensuring nuclear criticality safety during the packaging and transport of low {sup 235}U enriched uranium hexafluoride before its conversion to nuclear power reactor fuel. Moderation control has permitted the shipment of bulk quantities in large cylinders instead of in many smaller cylinders and, therefore, has resulted in economies without compromising safety. Overall safety and uranium accountability have been enhanced through the use of the moderation control. This paper discusses moderation control and the operating procedures to ensure that moderation control is maintained during packaging operations and transportation.

  17. Transition from Asymmetric to Symmetric Fission in the 235U(n,f) Reaction

    SciTech Connect

    Younes, W; Becker, J A; Bernstein, L A; Garrett, P E; McGrath, C A; McNabb, D P; Nelson, R O; Johns, G D; Wilburn, W S; Drake, D M

    2001-07-19

    Prompt {gamma} rays from the neutron-induced fission of {sup 235}U have been studied using the GEANIE spectrometer situated at the LANSCE/WNR ''white'' neutron facility. Gamma-ray production cross sections for 29 ground-state-band transitions in 18 even-even fission fragments were obtained as a function of incident neutron energy, using the time-of-flight technique. Independent yields were deduced from these cross sections and fitted with standard formulations of the fragment charge and mass distributions to study the transition from asymmetric to symmetric fission. The results are interpreted in the context of the disappearance of shell structure at high excitation energies.

  18. Critical mass experiment using {sup 235}U foils and lucite plates

    SciTech Connect

    Sanchez, R.; Butterfield, K.; Kimpland, R.; Jaegers, P.

    1998-09-01

    This experiment demonstrated how the neutron multiplication of a system increases as moderated material is placed between highly enriched uranium foils. In addition, this experiment served to demonstrate the hand-stacking technique and approach to criticality be remote operation. This experiment was designed by McLaughlin in the mid-seventies as part of the criticality safety course that is taught at the Los Alamos Critical Experiments Facility. The H/{sup 235}U ratio for this experiment was 215, which is the ratio at which the minimum critical mass for this configuration occurs.

  19. Collinear cluster tripartition channel in the reaction {sup 235}U(n{sub th}, f)

    SciTech Connect

    Pyatkov, Yu. V.; Kamanin, D. V.; Kopach, Yu. N.; Alexandrov, A. A.; Alexandrova, I. A.; Borzakov, S. B.; Voronov, Yu. N.; Zhuchko, V. E.; Kuznetsova, E. A. Panteleev, Ts.; Tyukavkin, A. N.

    2010-08-15

    Investigation of the {sup 235}U(n{sub th}, f) reaction using the miniFOBOS double-arm time-of-flight spectrometer of fission fragments confirmed manifestations of the earlier unknown many-body, at least ternary, decay involving almost collinear decay-product escape, which were first observed in the spontaneous fission of {sup 252}Cf(sf). The use of variables sensitive to the nuclear charge of fission fragments allowed the reliability of identification of decay events to be increased and new decay modes to be revealed.

  20. /sup 235/U and /sup 239/Pu sample-mass determinations and intercomparisons

    SciTech Connect

    Poenitz, W.P.; Meadows, J.W.

    1983-11-01

    The masses of fifteen /sup 235/U samples obtained from seven laboratories were determined and intercompared. The present results indicate that sample masses are well enough known (+- 0.3%) for the required high-accuracy-fission cross-section measurements. A comparison of four /sup 239/Pu samples indicates problems in the order of 1 to 3% which are more likely, to be related to counting efficiencies than to sample masses. The half-life of /sup 234/U was determined as (2.457 +- 0.005) . 10/sup 5/ yrs. 27 references.

  1. Mass estimates of very small reactor cores fueled by Uranium-235, U-233 and Cm-245

    NASA Astrophysics Data System (ADS)

    Wright, Steven A.; Lipinski, Ronald J.

    2001-02-01

    This paper explores the possibility of manufacturing very small reactors from U-235, U-233 and Cm-245. Pin type reactor systems fueled with uranium or curium metal zirconium hydride (UZrH or CmZrH) are compared with similar designs using U-235. Criticality measurements of homogeneous water uranium systems, suggest that reactor subsystem masses have a broad minimum for hydrogen-to-uranium atom ratios that vary from 25-250. This paper compares the masses of metal-hydride fueled reactor systems that use U-235, U-233, and Cm-245 fuel with hydrogen-to-metal atom ratios from 20-300 when cooled by gas (HeXe), liquid metal (Na), and water. The results indicate that water cooled reactors in general have the smallest reactor subsystem mass. For gas and liquid-metal cooled reactors U-233 subsystems have total masses that are about 1/2 those of similarly designed U-235 fuel reactors. Reactor subsystems consisting of 11.2% enriched Cm-245 (balance Cm-244) that can be obtained from fuel reprocessing have system masses comparable to that of U-233. The smallest reactor subsystem masses were on the order of 60-80 kg for U-233 fueled water cooled reactors. .

  2. New precision measurements of the 235U(n,γ) cross section.

    PubMed

    Jandel, M; Bredeweg, T A; Bond, E M; Chadwick, M B; Couture, A; O'Donnell, J M; Fowler, M; Haight, R C; Kawano, T; Reifarth, R; Rundberg, R S; Ullmann, J L; Vieira, D J; Wouters, J M; Wilhelmy, J B; Wu, C Y; Becker, J A

    2012-11-16

    The neutron capture cross section of (235)U was measured for the neutron incident energy region between 4 eV and 1 MeV at the DANCE facility at the Los Alamos Neutron Science Center with an unprecedented accuracy of 2-3% at 1 keV. The new methodology combined three independent measurements. In the main experiment, a thick actinide sample was used to determine neutron capture and neutron-induced fission rates simultaneously. In the second measurement, a fission tagging detector was used with a thin actinide sample and detailed characteristics of the prompt-fission gamma rays were obtained. In the third measurement, the neutron scattering background was characterized using a sample of (208)Pb. The relative capture cross section was obtained from the experiment with the thick (235)U sample using a ratio method after the subtraction of the fission and neutron scattering backgrounds. Our result indicates errors that are as large as 30% in the 0.5-2.5 keV region, in the current knowledge of neutron capture as embodied in major nuclear data evaluations. Future modifications of these databases using the improved precision data given herein will have significant impacts in neutronics calculations for a variety of nuclear technologies.

  3. R-matrix analysis of the /sup 235/U neutron cross sections

    SciTech Connect

    Leal, L.C.; de Saussure, G.; Perez, R.B.

    1988-01-01

    The ENDFB-V representation of the /sup 235/U neutron cross sections in the resolved resonance region is unsatisfactory: below 1 eV the cross sections are given by ''smooth files'' (file 3) rather than by resonance parameters; above 1 eV the single-level formalism used by ENDFB-V necessitates a structured file 3 contribution consisting of more than 1300 energy points; furthermore, information on level-spins has not been included. Indeed the ENDFB-V /sup 235/U resonance region is based on an analysis done in 1970 for ENDFB-III and therefore does not include the results of high quality measurements done in the past 18 years. The present paper presents the result of an R-matrix multilevel analysis of recent measurements as well as older data. The analysis also extends the resolved resonance region from its ENDFB-V upper limit of 81 eV to 110 eV. 13 refs., 2 figs., 1 tab

  4. Consistent Data Assimilation of Actinide Isotopes: 235U and 239Pu

    SciTech Connect

    G. Palmiottti; H. Hiruta; M. Salvatores

    2011-09-01

    In this annual report we illustrate the methodology of the consistent data assimilation that allows to use the information coming from integral experiments for improving the basic nuclear parameters used in cross section evaluation. A series of integral experiments were analyzed using the EMPIRE evaluated files for {sup 235}U, {sup 238}U, and {sup 239}Pu. Inmost cases the results have shown quite large worse results with respect to the corresponding existing evaluations available for ENDF/B-VII. The observed discrepancies between calculated and experimental results were used in conjunction with the computed sensitivity coefficients and covariance matrix for nuclear parameters in a consistent data assimilation. Only the GODIVA and JEZEBEL experimental results were used, in order to exploit information relative to the isotope of interest that are, in this particular case: {sup 235}U and {sup 239}Pu. The results obtained by the consistent data assimilation indicate that with reasonable modifications (mostly within the initial standard deviation) it is possible to eliminate the original large discrepancies on the K{sub eff} of the two critical configurations. However, some residual discrepancy remains for a few fission spectral indices that are, most likely, to be attributed to the detector cross sections.

  5. Cross-sections of the reaction 232Th(p,3n)230Pa for production of 230U for targeted alpha therapy.

    PubMed

    Morgenstern, Alfred; Apostolidis, Christos; Bruchertseifer, Frank; Capote, Roberto; Gouder, Thomas; Simonelli, Federica; Sin, Mihaela; Abbas, Kamel

    2008-10-01

    (230)U/(226)Th is a promising novel alpha-emitter system for application in targeted alpha therapy of cancer. The therapeutic nuclides can be produced by proton irradiation of natural (232)Th according to the reaction (232)Th(p,3n)(230)Pa, followed by subsequent beta decay of (230)Pa to (230)U. In this study, the experimental excitation function for the (232)Th(p,3n)(230)Pa reaction up to 34 MeV proton energy has been measured using the stacked-foil technique. The proton energies in the various foils were calculated with the SRIM 2003 code and gamma-ray spectrometry was used to measure the activities of the various radioisotopes produced. The measured cross-sections are in good agreement with selected literature values and with model calculations using the EMPIRE II code. The reaction (232)Th(p,3n)(230)Pa allows the production of carrier-free (230)U in clinically relevant levels.

  6. Cross-sections of the reaction 232Th(p,3n)230Pa for production of 230U for targeted alpha therapy.

    PubMed

    Morgenstern, Alfred; Apostolidis, Christos; Bruchertseifer, Frank; Capote, Roberto; Gouder, Thomas; Simonelli, Federica; Sin, Mihaela; Abbas, Kamel

    2008-10-01

    (230)U/(226)Th is a promising novel alpha-emitter system for application in targeted alpha therapy of cancer. The therapeutic nuclides can be produced by proton irradiation of natural (232)Th according to the reaction (232)Th(p,3n)(230)Pa, followed by subsequent beta decay of (230)Pa to (230)U. In this study, the experimental excitation function for the (232)Th(p,3n)(230)Pa reaction up to 34 MeV proton energy has been measured using the stacked-foil technique. The proton energies in the various foils were calculated with the SRIM 2003 code and gamma-ray spectrometry was used to measure the activities of the various radioisotopes produced. The measured cross-sections are in good agreement with selected literature values and with model calculations using the EMPIRE II code. The reaction (232)Th(p,3n)(230)Pa allows the production of carrier-free (230)U in clinically relevant levels. PMID:18374585

  7. Reaction paths and host phases of uranium isotopes (235U; 238U), Saanich Inlet

    NASA Astrophysics Data System (ADS)

    Amini, M.; Holmden, C. E.; Francois, R. H.

    2009-12-01

    In recent times, Uranium has become increasingly the focus of stable isotope fractionation studies. Variations in 238U/235U have been reported as a result of redox reactions [1,2] from the nuclear field shift effect [3], and a mass-dependent, microbially-mediated, kinetic isotope effect [4]. The 238U/235U variability caused by changes in environmental redox conditions leads to an increase in the 238U/235U ratios of the reduced U species sequestered into marine sediments. This points to U isotope variability as a new tool to study ancient ocean redox changes. However, the process by which reduced sediments become enriched in the heavy isotopes of U is not yet known, and hence the utility of 238U/235U as a redox tracer remains to be demonstrated. In order to further constrain sedimentary U enrichment and related isotope effect, we are investigating U isotopic compositions of water samples and fresh surface sediment grab samples over a range of redox conditions in the seasonally anoxic Saanich Inlet, on the east coast of Vancouver Island. U was sequentially extracted from sediments in order to characterize specific fractions for their isotopic composition. The measurements were carried out by MC-ICPMS using 233U/236U-double spike technique. The data are reported as δ238U relative to NBL 112a with a 238U/235U ratio of 137.88 (2sd). External precision is better than 0.10‰ (2sd). Fifteeen analyses of seawater yielded δ238U of -0.42±0.08‰ (2sd). The results for the water samples indicate a homogenous δ238U value throughout the Saanich Inlet water column that matches the global seawater signature. All of the water samples from above and below average -0.42±0.05‰ (2sd). In contrast, a plankton net sample yielded a distinctly different, (about 0.5‰ lighter) isotope value. Bacterial reduction experiments [4] have also shown isotope enrichment factors of about -0.3‰. In addition, metal isotope fractionation occurs during adsorption with the light isotope being

  8. 40 K Fastrac II Test

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A 40 K Fastrac II duration test performed at Marshall Test Stand 116. The purpose of this test was to gauge the length of time between contact of TEA (Triethylenealuminum) and LOX (liquid oxygen) as an ignitor for the Fastrac engine.

  9. Fission fragments mass distributions of nuclei populated by the multinucleon transfer channels of the 18O + 232Th reaction

    NASA Astrophysics Data System (ADS)

    Léguillon, R.; Nishio, K.; Hirose, K.; Makii, H.; Nishinaka, I.; Orlandi, R.; Tsukada, K.; Smallcombe, J.; Chiba, S.; Aritomo, Y.; Ohtsuki, T.; Tatsuzawa, R.; Takaki, N.; Tamura, N.; Goto, S.; Tsekhanovich, I.; Petrache, C. M.; Andreyev, A. N.

    2016-10-01

    It is shown that the multinucleon transfer reactions is a powerful tool to study fission of exotic neutron-rich actinide nuclei, which cannot be accessed by particle-capture or heavy-ion fusion reactions. In this work, multinucleon transfer channels of the 18O + 232Th reaction are used to study fission of fourteen nuclei 231,232,233,234Th, 232,233,234,235,236Pa, and 234,235,236,237,238U. Identification of fissioning nuclei and of their excitation energy is performed on an event-by-event basis, through the measurement of outgoing ejectile particle in coincidence with fission fragments. Fission fragment mass distributions are measured for each transfer channel, in selected bins of excitation energy. In particular, the mass distributions of 231,234Th and 234,235,236Pa are measured for the first time. Predominantly asymmetric fission is observed at low excitation energies for all studied cases, with a gradual increase of the symmetric mode towards higher excitation energy. The experimental distributions are found to be in general agreement with predictions of the fluctuation-dissipation model.

  10. Study of the violent collisions between {sup 63}Cu+{sup 232}Th at 35 MeV/nucleon

    SciTech Connect

    Cibor, J.; Majka, Z.; Kozik, T.; Staszel, P.; Sosin, Z.; Hagel, K.; Li, J.; Lou, L.; Tezkratt, R.; Utley, D.; Wada, R.; Xiao, B.; Natowitz, J.

    1997-01-01

    A study of the decay of hot and heavy composite nuclei produced in the violent collisions between {sup 63}Cu and {sup 232}Th at 35A MeV is presented. The measurement of fission fragment correlations indicates that {approximately} 70{percent} of the projectile linear momentum can be transferred to the fissioning system. Heavy reaction products were observed at a laboratory angle of {theta}=6{degree} in coincidence with neutrons, light charged particles, and intermediate mass fragments. The dynamical aspects of the collisions between the projectile and target nuclei were investigated using the computer code CHIMERA which is based upon the molecular dynamics concept. Asymptotic characteristics of the reaction products were confronted with results of calculations of the tandem CHIMERA plus GEMINI codes. The data and model comparisons show that a composite system of mass as high as 275 amu and with an excitation energy {approximately} 1 GeV is formed in the most violent collisions. Some of the heavy reaction remnants are located on the fragment mass versus velocity plane inside the area where the evaporation residues resulting from the decay of the hot composite system are expected. A high neutron multiplicity associated with these events indicates their origin in the most dissipative events. However, a low cross section for the production of these remnants and the close similarity of their characteristics to the fission fragments do not allow more conclusive statements. {copyright} {ital 1997} {ital The American Physical Society}

  11. Retardation of [sup 238]U and [sup 232]Th decay chain radionuclides in Long Island and Connecticut aquifers

    SciTech Connect

    Copenhaver, S.A.; Krishnaswami, S.; Turekian, K.K. ); Epler, N.; Cochran, J.K. )

    1993-02-01

    Knowledge of the ability of an aquifer to retard the groundwater transport of toxic or radioactive ions can be inferred from the analysis of groundwater for the radionuclides of the [sup 238]U- and [sup 232]Th-decay chains. Groundwaters of varying chemical composition were analyzed from wells in Long Island, New York, and Connecticut. Aquifer lithologies are arkose, quartz sandstone, granite, and glacial drift. Adsorption (k[sub 1]) and desorption (k[sub 2]) coefficients for Ra and Pb were calculated using [sup 222]Rn activity as a measure of the supply of other [alpha]-recoil nuclides. Laboratory tests of the validity of this assumption were made by measuring the flux of [sup 224]Ra and [sup 222]Rn from aquifer solids. The ratio k[sub 1]/k[sub 2] is the distribution coefficient, K, which is effective equal to R[sub f], the retardation factor. The average value of K for Ra is 6 [times] 10[sup 2] in Long Island aquifers and 5 [times] 10[sup 4] in Connecticut. The distribution coefficient for Pb is 10[sup 4] in Long Island and 10[sup 5] in Connecticut. Results from this and other studies reveal a strong dependence of retardation on pH, f[sub o[sub 2

  12. Investigating Prompt Fission Neutron Emission from 235U(n,f) in the Resolved Resonance Region

    NASA Astrophysics Data System (ADS)

    Göök, Alf; Hambsch, Franz-Josef; Oberstedt, Stephan

    2016-03-01

    Investigations of prompt emission in fission is of importance in understanding the fission process in general and the sharing of excitation energy among the fission fragments in particular. Experimental activities at IRMM on prompt neutron emission from fission in response to OECD/NEA nuclear data requests is presented in this contribution. Main focus lies on currently on-going investigations of prompt neutron emission from the reaction 235U(n,f) in the region of the resolved resonances. For this reaction strong fluctuations of fission fragment mass distributions and mean total kinetic energy have been observed [Nucl. Phys. A 491, 56 (1989)] as a function of incident neutron energy in the resonance region. In addition fluctuations of prompt neutron multiplicities were also observed [Phys. Rev. C 13, 195 (1976)]. The goal of the present study is to verify the current knowledge of prompt neutron multiplicity fluctuations and to study correlations with fission fragment properties.

  13. High-Resolution Correlated Fission Product Measurements of 235U (nth , f) with SPIDER

    NASA Astrophysics Data System (ADS)

    Shields, Dan; Spider Team

    2015-10-01

    The SPIDER detector (SPectrometer for Ion DEtermination in fission Research) has obtained high-resolution, moderate-efficiency, correlated fission product data needed for many applications including the modeling of next generation nuclear reactors, stockpile stewardship, and the fundamental understanding of the fission process. SPIDER simultaneously measures velocity and energy of both fission products to calculate fission product yields (FPYs), neutron multiplicity (ν), and total kinetic energy (TKE). These data will be some of the first of their kind available to nuclear data evaluations. An overview of the SPIDER detector, analytical method, and preliminary results for 235U (nth , f) will be presented. LA-UR-15-20130 This work benefited from the use of the LANSCE accelerator facility and was performed under the auspices of the US Department of Energy by Los Alamos Security, LLC under Contract DE-AC52-06NA25396.

  14. 238U/235U determinations of some commonly used reference materials and U-bearing accessory minerals (Invited)

    NASA Astrophysics Data System (ADS)

    Condon, D.; Noble, S.; McLean, N.; Bowring, S. A.

    2009-12-01

    We have determined 238U/235U ratios for a suite of commonly used natural (CRM 112a, SRM 950a, HU-1) and synthetic (IRMM 184 and CRM U500) uranium reference materials in addition to several U-bearing accessory phases (zircon and monazite) by thermal ionisation mass-spectrometry (TIMS) using the IRMM 3636 233U-236U double spike to accurately correct for mass fractionation. The 238U/235U values for the natural uranium reference materials differ, by up to 0.1%, from the widely used ‘consensus’ value (137.88) with all having 238U/235U values less than 137.88. Similarly, initial 238U/235U data from zircon and monazite yield 238U/235U values that are lower than the ‘consensus’ value. The data obtained from U-bearing minerals is used to assess how the uncertainty in the 238U/235U ratio contributes to the systematic discordance observed in 238U/206Pb and 235U/207Pb dates (Mattinson, 2000; Schoene et al., 2006) which has traditionally been wholly attributed to error in the U decay constants. The 238U/235U determinations made on the synthetic reference materials yield results that are considerably more precise and accurate than the certified values (0.02% vs. 0.1% for CRM U500). The calibration of isotopic tracers used for U-daughter geochronology that are partially based upon these reference materials, and the resultant age determinations, will benefit from increased accuracy and precision. Mattinson, J.M., 2000. Revising the “gold standard”—the uranium decay constants of Jaffey et al., 1971. Eos Trans. AGU, Spring Meet. Suppl., Abstract V61A-02. Schoene B., Crowley J.L., Condon D.C., Schmitz M.D., Bowring S.A., 2006, Reassessing the uranium decay constants for geochronology using ID-TIMS U-Pb data. Geochimica et Cosmochimica Acta 70: 426-445

  15. A beta-alpha coincidence counting system for measurement of trace quantities of 238U and 232Th in aqueous samples at the Sudbury Neutrino Observatory.

    NASA Astrophysics Data System (ADS)

    Dawson, M.; Doucas, G.; Fergani, H.; Jelley, N. A.; Majerus, S.; O'Keeffe, H. M.; Peeters, S. J. M.; Perry, C.

    2016-08-01

    The Sudbury Neutrino Observatory experiment was built to measure the total flux of 8B solar neutrinos via the neutral current disintegration deuterium nuclei. This process can be mimiced by daughter isotopes of 232Th and 238U which can photodisintegrate the deuterium nucleus. Measurement of the concentration of such radioisotopes in the heavy water was critical to the success of the experiment. A radium assay technique using Hydrous Titanium Oxide coated filters was developed for this purpose and it was used in conjunction with a delayed beta-alpha coincidence counting system. The design, calibration and operation of this counting system are described in this paper. The counting efficiency for 232Th (224Ra) and 238U (226Ra) were measured to be 50 ± 5% and 62 ± 7%

  16. 238U/235U variations in meteorites: extant 247Cm and implications for Pb-Pb dating.

    PubMed

    Brennecka, G A; Weyer, S; Wadhwa, M; Janney, P E; Zipfel, J; Anbar, A D

    2010-01-22

    The 238U/235U isotope ratio has long been considered invariant in meteoritic materials (equal to 137.88). This assumption is a cornerstone of the high-precision lead-lead dates that define the absolute age of the solar system. Calcium-aluminum-rich inclusions (CAIs) of the Allende meteorite display variable 238U/235U ratios, ranging between 137.409 +/- 0.039 and 137.885 +/- 0.009. This range implies substantial uncertainties in the ages that were previously determined by lead-lead dating of CAIs, which may be overestimated by several million years. The correlation of uranium isotope ratios with proxies for curium/uranium (that is, thorium/uranium and neodymium/uranium) provides strong evidence that the observed variations of 238U/235U in CAIs were produced by the decay of extant curium-247 to uranium-235 in the early solar system, with an initial 247Cm/235U ratio of approximately 1.1 x 10(-4) to 2.4 x 10(-4).

  17. Combined 238U/235U and Pb Isotopics of Planetary Core Material: The Absolute Age of the IVA Iron Muonionalusta

    NASA Astrophysics Data System (ADS)

    Brennecka, G. A.; Amelin, Y.; Kleine, T.

    2016-08-01

    We report a measured 238U/235U for the IVA iron Muonionalusta. This measured value requires an age correction of ~7 Myr to the previously published Pb-Pb age. This has major implications for our understanding of planetary core formation and cooling.

  18. Measurement of cross sections for the {sup 232}Th(P,4n){sup 229}Pa reaction at low proton energies

    SciTech Connect

    Jost, C. U.; Griswold, J. R.; Bruffey, S. H.; Mirzadeh, S.; Stracener, D. W.; Williams, C. L.

    2013-04-19

    The alpha-emitters {sup 225}Ac and {sup 213}Bi are of great interest for alpha-radioimmunotherapy which uses radioisotopes attached to cancer-seeking antibodies to efficiently treat various types of cancers. Both radioisotopes are daughters of the long-lived {sup 229}Th(t{sub 1/2} = 7880y). {sup 229}Th can be produced by proton irradiation of {sup 232}Th and {sup 230}Th, either directly or through production of isobars that beta-decay into {sup 229}Th. To obtain excitation functions, {sup 232}Th and {sup 230}Th have been irradiated at the On-Line Test Facility at the Holifield Radioactive Ion Beam Facility at ORNL. Benchmark tests conducted with Cu and Ni foils show very good agreement with literature results. The experiments with thorium targets were focused on the production of {sup 229}Pa and its daughter {sup 225}Ac from both {sup 232}Th and {sup 230}Th. Differential cross-sections for production of {sup 229}Pa and other Pa isotopes have been obtained.

  19. Determination of 235U enrichment with a large volume CZT detector

    NASA Astrophysics Data System (ADS)

    Mortreau, Patricia; Berndt, Reinhard

    2006-01-01

    Room-temperature CdZnTe and CdTe detectors have been routinely used in the field of Nuclear Safeguards for many years [Ivanov et al., Development of large volume hemispheric CdZnTe detectors for use in safeguards applications, ESARDA European Safeguards Research and Development Association, Le Corum, Montpellier, France, 1997, p. 447; Czock and Arlt, Nucl. Instr. and Meth. A 458 (2001) 175; Arlt et al., Nucl. Instr. and Meth. A 428 (1999) 127; Lebrun et al., Nucl. Instr. and Meth. A 448 (2000) 598; Aparo et al., Development and implementation of compact gamma spectrometers for spent fuel measurements, in: Proceedings, 21st Annual ESARDA, 1999; Arlt and Rudsquist, Nucl. Instr. and Meth. A 380 (1996) 455; Khusainov et al., High resolution pin type CdTe detectors for the verification of nuclear material, in: Proceedings, 17th Annual ESARDA European Safeguards Research and Development Association, 1995; Mortreau and Berndt, Nucl. Instr. and Meth. A 458 (2001) 183; Ruhter et al., UCRL-JC-130548, 1998; Abbas et al., Nucl. Instr. and Meth. A 405 (1998) 153; Ruhter and Gunnink, Nucl. Instr. and Meth. A 353 (1994) 716]. Due to their performance and small size, they are ideal detectors for hand-held applications such as verification of spent and fresh fuel, U/Pu attribute tests as well as for the determination of 235U enrichment. The hemispherical CdZnTe type produced by RITEC (Riga, Latvia) [Ivanov et al., 1997] is the most widely used detector in the field of inspection. With volumes ranging from 2 to 1500 mm 3, their spectral performance is such that the use of electronic processing to correct the pulse shape is not required. This paper reports on the work carried out with a large volume (15×15×7.5 mm 3) and high efficiency hemispherical CdZnTe detector for the determination of 235U enrichment. The measurements were made with certified uranium samples whose enrichment ranging from 0.31% to 92.42%, cover the whole range of in-field measurement conditions. The interposed

  20. Neutron experiments at Portsmouth for measuring flow and {sup 235}U content in UF{sub 6} gas

    SciTech Connect

    Stromswold, D C; Reeder, P L; Peurrung, A J

    1997-04-01

    The Portsmouth Gaseous Diffusion Plant produces enriched uranium for use in commercial power reactors. The plant also aids disposal of excess high-enrichment uranium (HEU) by blending it with lower-enrichment material. Experiments were conducted to test two neutron-based methods for monitoring the down-blending of HEU. Results of the initial experiments showed that gas (on-off) could be detected, but that additional tests and data are needed to quantify the flow velocity and {sup 235}U content. The experiments used a {sup 252}Cf neutron source to induce fission in a small fraction of the {sup 235}U contained in the UF{sub 6} gas. The first method measured the attenuation of neutrons passing through the low-pressure UF{sub 6} gas in a 7.6-cm diameter pipe. The concept was based on the fact that some of the thermal neutrons are absorbed by {sup 235}U, thus changing the observed count rate. The second method, tested on a 20-cm diameter pipe where gas pressure was higher, used a modulated neutron flux to induce fission in the {sup 235}U. Modulation was achieved by moving a neutron source. During both experiments, plant monitoring equipment showed that light gases (freon, oxygen, and nitrogen) were present in widely varying amounts, along with the UF{sub 6} gas. These gases may have affected the experimental results, at least to the extent that they replaced UF{sub 6}. This report also contains results of computer simulations and tests performed on the electronics after the experiments were completed at Portsmouth. Recommendations are made for follow-on work to measure the flow velocity and {sup 235}U content.

  1. Fission and binary fragmentation reactions in {sup 80}Se+{sup 208}Pb and {sup 80}Se+{sup 232}Th systems

    SciTech Connect

    Thomas, R. G.; Saxena, A.; Sahu, P. K.; Kailas, S.; Kapoor, S. S.; Choudhury, R. K.; Govil, I. M.; Barbui, M.; Cinausero, M.; Prete, G.; Rizzi, V.; Fabris, D.; Lunardon, M.; Moretto, S.; Viesti, G.; Nebbia, G.; Pesente, S.; Dalena, B.; D'Erasmo, G.; Fiore, E. M.

    2007-02-15

    Fission and binary fragmentation of the excited nuclear systems of Z=116 and 124 were investigated using the reactions induced by {sup 80}Se beams on {sup 208}Pb and {sup 232}Th targets at bombarding energies ranging from 470 to 630 MeV. The mass and kinetic energy of the binary reaction products were reconstructed by measuring their velocities by the time-of-flight method and the angles of emission using multiwire proportional chambers. Total neutron multiplicities were measured in coincidence with the fragments, using an array of neutron detectors. The fragment mass-energy correlation was studied for the two systems. The average total kinetic energy (TKE) of fragments for the {sup 80}Se+{sup 208}Pb system agrees with earlier measurements and with Viola's systematics in the mass symmetric region for compound nucleus fission, whereas for the {sup 80}Se+{sup 232}Th system, the TKE values are significantly lower. This is also consistent with higher values of total neutron multiplicities observed for the case of {sup 80}Se+{sup 232}Th at comparable available energies. From an extrapolation of the measured total neutron multiplicities for the mass symmetric region to zero compound nucleus excitation energy, the average number of prompt neutrons expected to be emitted in the spontaneous fission of the superheavy Z=116 has been estimated to be {nu}{sub tot}{sup sf}=10{+-}2, which is consistent with the value derived for the same compound nucleus populated in the {sup 56}Fe+{sup 232}Th reaction in an earlier work. In the case of the {sup 80}Se+{sup 232}Th system, similar analysis was carried out by taking the average TKE from Viola's systematics for estimating the available energy for particle emission corresponding to compound nucleus fission. In this way, by extrapolating the observed neutron multiplicities to zero compound nucleus excitation energy, a value of {nu}{sub tot}{sup sf}=15{+-}2 was obtained for the spontaneous fission of the superheavy Z=124 nucleus. The

  2. Characterization of 235U Targets for the Development of a Secondary Neutron Fluence Standard

    NASA Astrophysics Data System (ADS)

    Heyse, J.; Anastasiou, M.; Eykens, R.; Moens, A.; Plompen, A. J. M.; Schillebeeckx, P.; Sibbens, G.; Vanleeuw, D.; Wynants, R.

    2014-05-01

    The MetroFission project, a Joint Research Project within the European Metrology Research Program (EMRP), aims at addressing a number of metrological problems involved in the design of proposed Generation IV nuclear reactors. As part of this project a secondary neutron fluence standard is being developed and tested at the neutron time-of-flight facility GELINA of the JRC Institute for Reference Materials and Measurements (IRMM). This secondary standard will help to reach the neutron cross section measurement uncertainties required for the design of new generation power plants and fuel cycles. Such a neutron fluence device contains targets for which the neutron induced cross section is considered to be a standard. A careful preparation and characterization of these samples is an essential part of its development. In this framework a set of 235U targets has been produced by vacuum deposition of UF4 on aluminum backings by the target preparation laboratory at IRMM. These targets have been characterized for both their total mass and mass distribution over the sample area.

  3. Calculation of resonance self-shielding for {sup 235}U from 0 to 2250 eV

    SciTech Connect

    Leal, L.C.; Larson, N.M.; Derrien, H.; Santos, G.R.

    1998-08-01

    Over the years, the evaluated {sup 235}U cross sections in the resolved energy range have been extensively revised. A major accomplishment was the first evaluation released to the ENDF/B-VI library. In that evaluation, the low energy range bound was lowered to 10{sup {minus}5} eV, and the upper limit raised to 2,250 eV. Several high-resolution measurements in conjunction with the Bayesian computer code SAMMY were used to perform the analysis of the {sup 235}U resonance parameters. SAMMY uses the Reich-Moore formalism, which is adequate for representing neutron cross sections of fissile isotopes, and a generalized least-squares (Bayes) technique for determining the energy-dependence of the neutron cross sections. Recently a re-evaluation of the {sup 235}U cross section in the resolved resonance region was completed. This evaluation has undergone integral tests in various laboratories throughout the USA and abroad. The evaluation has been accepted for inclusion in ENDF/B-VI release 5. The intent of this work is to present results of calculations of self-shielded fission rates carried out with these resonance parameters and to compare those fission rates with experimental data. Results of this comparison study provide an assessment of the resonance parameters with respect to the calculation of self-shielded group cross sections.

  4. Measurement of the Total Kinetic Energy Release (TKE) in 232 Th(n,f) with En = 2.59 - 87.31 MeV

    NASA Astrophysics Data System (ADS)

    King, Jonathan; Yanez, Ricardo; Barrett, Jonathan; Loveland, Walter; Tovesson, Fredrik; Fotiades, Nick; Lee, Hye Young

    2015-04-01

    Experimental results for the Total Kinetic Energy Release (TKE) of 232 Th(n,f) with En = 2.59 - 87.31 MeV will be presented. The experiment was performed at the 15R beamline at the Weapons Neutron Research(WNR) facility at LANL-LANSCE. WNR provides a white spectrum of neutrons peaking at 2 MeV and reaching up to 800 MeV, with neutron energies being deduced from measurements of the neutron time of flight (TOF). A thin-backed 232 ThF4 target of 2 cm diameter with a thorium areal density of 178.9 μg/cm2 was placed between two arrays of Hammamatsu PIN diodes (active area 4 cm2 each). The beam was collimated to 1 cm diameter. The target was placed 45 degrees off of the beam axis, with the detectors at 60 degrees and 120 degrees from the beam axis. Over 25,000 fission fragment coincidence events were recorded, allowing for sixteen energy bins between 2.59 and 87.31 MeV. We believe that this will be the most comprehensive published measurement of the TKE for 232 Th(n,f) with En = 2.59 - 87.31 MeV. This work was supported in part by the Director, Office of Energy Research, Division of Nuclear Physics of the Office of High Energy and Nuclear Physics of the USDoE under Grant DE-FG06-97ER41026. This work has benefited from the use of the Los Alamos Neutron Science Center at the Los Alamos National Laboratory. This facility is funded by the USDoE under DOE Contract No. DE-AC52-06NA25396.

  5. Cost-based optimizations of power density and target-blanket modularity for {sup 232}Th/{sup 233}U-based ADEP

    SciTech Connect

    Krakowski, R.A.

    1995-07-01

    A cost-based parametric systems model is developed for an Accelerator-Driven Energy Production (ADEP) system based on a {sup 232}Th/{sup 233}U fuel cycle and a molten-salt (LiF/BeF{sub 2}/ThF{sub 3}) fluid-fuel primary system. Simplified neutron-balance, accelerator, reactor-core, chemical-processing, and balance-of-plant models are combined parametrically with a simplified costing model. The main focus of this model is to examine trade offs related to fission power density, reactor-core modularity, {sup 233}U breeding rate, and fission product transmutation capacity.

  6. Measurements of absolute delayed neutron yield and group constants in the fast fission of {sup 235}U and {sup 237}Np

    SciTech Connect

    Loaiza, D.J.; Brunson, G.; Sanchez, R.; Butterfield, K.

    1998-03-01

    The delayed neutron activity resulting from the fast induced fission of {sup 235}U and {sup 237}Np has been studied. The six-group decay constants, relative abundances, and absolute yield of delayed neutrons from fast fission of {sup 235}U and {sup 237}Np were measured using the Godiva IV fast assembly at the Los Alamos Critical Experiments Facility. The absolute yield measured for {sup 235}U was 0.0163 {+-} 0.0008 neutron/fission. This value compares very well with the well-established Keepin absolute yield of 0.0165 {+-} 0.0005. The absolute yield value measured for {sup 237}Np was 0.0126 {+-} 0.0007. The measured delayed neutron parameters for {sup 235}U are corroborated with period (e-folding time) versus reactivity calculations.

  7. Current Issues in Nuclear Data Evaluation Methodology: {sup 235}U Prompt Fission Neutron Spectra and Multiplicity for Thermal Neutrons

    SciTech Connect

    Trkov, A.; Capote, R.; Pronyaev, V.G.

    2015-01-15

    Issues in evaluation methodology of the prompt fission neutron spectra (PFNS) and neutron multiplicity for the thermal-neutron-induced fission of the {sup 235}U are discussed. The inconsistency between the experimental differential and integral data is addressed. By using differential data as ”shape data” good consistency was achieved between available sets of differential data. Integral dosimetry data have been used to define the PFNS slope at high outgoing neutron energies, where the quality of the differential data is poor. The inclusion into the fit of measured integral (spectrum-averaged) cross sections had a very small impact in the region where differential PFNS data are abundant and accurate, but removed the discrepancy with integral data at higher neutron emission energies. All experimental data are consistently fitted giving a PFNS average energy of 2.008 MeV. The impact on criticality prediction of the newly evaluated PFNS was tested. The highly enriched {sup 235}U solution assemblies with high leakage HEU-SOL-THERM-001 and HEU-SOL-THERM-009 benchmarks are the most sensitive to the PFNS. Criticality calculations for those solutions show a significant increase in reactivity if the average neutron energy of the fission neutrons is reduced from the ENDF/B-VI.5 value of 2.03 MeV. The proposed reduction of the PFNS average energy by 1.1% can be compensated by reducing the average number of neutrons per fission ν{sup ¯} at the thermal energy to the Gwin et al. measured value. The simple least-squares PFNS fit was confirmed by a more sophisticated combined fit of differential PFNS data for {sup 233,235}U, {sup 239}Pu and {sup 252}Cf nuclides with the generalised least-squares method using the GMA and GANDR codes.

  8. Energy dependence of mass, charge, isotopic, and energy distributions in neutron-induced fission of 235U and 239Pu

    NASA Astrophysics Data System (ADS)

    Pasca, H.; Andreev, A. V.; Adamian, G. G.; Antonenko, N. V.; Kim, Y.

    2016-05-01

    The mass, charge, isotopic, and kinetic-energy distributions of fission fragments are studied within an improved scission-point statistical model in the reactions 235U+n and 239Pu+n at different energies of the incident neutron. The charge and mass distributions of the electromagnetic- and neutron-induced fission of 214,218Ra, 230,232,238U are also shown. The available experimental data are well reproduced and the energy-dependencies of the observable characteristics of fission are predicted for future experiments.

  9. Fission Fragment Angular Distribution measurements of 235U and 238U at CERN n_TOF facility

    NASA Astrophysics Data System (ADS)

    Leal-Cidoncha, E.; Durán, I.; Paradela, C.; Tarrío, D.; Leong, L. S.; Tassan-Got, L.; Audouin, L.; Altstadt, S.; Andrzejewski, J.; Barbagallo, M.; Bécares, V.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Boccone, V.; Bosnar, D.; Brugger, M.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Domingo-Pardo, C.; Dressler, R.; Dzysiuk, N.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Ganesan, S.; García, A. R.; Giubrone, G.; Gómez-Hornillos, M. B.; Gonçalves, I. F.; González-Romero, E.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Gurusamy, P.; Hernández-Prieto, A.; Jenkins, D. G.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karadimos, D.; Kivel, N.; Koehler, P.; Kokkoris, M.; Krtička, M.; Kroll, J.; Lampoudis, C.; Langer, C.; Lederer, C.; Leeb, H.; Lo Meo, S.; Losito, R.; Mallick, A.; Manousos, A.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P. F.; Mastromarco, M.; Meaze, M.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Mondelaers, W.; Pavlik, A.; Perkowski, J.; Plompen, A.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego, A.; Robles, M. S.; Roman, F.; Rubbia, C.; Sabaté-Gilarte, M.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Tagliente, G.; Tain, J. L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Versaci, R.; Vermeulen, M. J.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiß, C.; Wright, T.; Žugec, P.

    2016-03-01

    Neutron-induced fission cross sections of 238U and 235U are used as standards in the fast neutron region up to 200 MeV. A high accuracy of the standards is relevant to experimentally determine other neutron reaction cross sections. Therefore, the detection effciency should be corrected by using the angular distribution of the fission fragments (FFAD), which are barely known above 20 MeV. In addition, the angular distribution of the fragments produced in the fission of highly excited and deformed nuclei is an important observable to investigate the nuclear fission process. In order to measure the FFAD of neutron-induced reactions, a fission detection setup based on parallel-plate avalanche counters (PPACs) has been developed and successfully used at the CERN-n_TOF facility. In this work, we present the preliminary results on the analysis of new 235U(n,f) and 238U(n,f) data in the extended energy range up to 200 MeV compared to the existing experimental data.

  10. A generalized method for characterization of 235U and 239Pu content using short-lived fission product gamma spectroscopy

    NASA Astrophysics Data System (ADS)

    Knowles, Justin; Skutnik, Steven; Glasgow, David; Kapsimalis, Roger

    2016-10-01

    Rapid nondestructive assay methods for trace fissile material analysis are needed in both nuclear forensics and safeguards communities. To address these needs, research at the Oak Ridge National Laboratory High Flux Isotope Reactor Neutron Activation Analysis facility has developed a generalized nondestructive assay method to characterize materials containing fissile isotopes. This method relies on gamma-ray emissions from short-lived fission products and makes use of differences in fission product yields to identify fissile compositions of trace material samples. Although prior work has explored the use of short-lived fission product gamma-ray measurements, the proposed method is the first to provide a complete characterization of isotopic identification, mass ratios, and absolute mass determination. Successful single fissile isotope mass recoveries of less than 6% recovery bias have been conducted on standards of 235U and 239Pu as low as 12 ng in less than 10 minutes. Additionally, mixtures of fissile isotope standards containing 235U and 239Pu have been characterized as low as 198 ng of fissile mass with less than 7% recovery bias. The generalizability of this method is illustrated by evaluating different fissile isotopes, mixtures of fissile isotopes, and two different irradiation positions in the reactor. It is anticipated that this method will be expanded to characterize additional fissile nuclides, utilize various irradiation facilities, and account for increasingly complex sample matrices.

  11. A generalized method for characterization of 235U and 239Pu content using short-lived fission product gamma spectroscopy

    DOE PAGES

    Knowles, Justin R.; Skutnik, Steven E.; Glasgow, David C.; Kapsimalis, Roger J.

    2016-06-23

    Rapid non-destructive assay methods for trace fissile material analysis are needed in both nuclear forensics and safeguards communities. To address these needs, research at the High Flux Isotope Reactor Neutron Activation Analysis laboratory has developed a generalized non-destructive assay method to characterize materials containing fissile isotopes. This method relies on gamma-ray emissions from short-lived fission products and capitalizes off of differences in fission product yields to identify fissile compositions of trace material samples. Although prior work has explored the use of short-lived fission product gamma-ray measurements, the proposed method is the first to provide a holistic characterization of isotopic identification,more » mass ratios, and absolute mass determination. Successful single fissile isotope mass recoveries of less than 6% error have been conducted on standards of 235U and 239Pu as low as 12 nanograms in less than 10 minutes. Additionally, mixtures of fissile isotope standards containing 235U and 239Pu have been characterized as low as 229 nanograms of fissile mass with less than 12% error. The generalizability of this method is illustrated by evaluating different fissile isotopes, mixtures of fissile isotopes, and two different irradiation positions in the reactor. Furthermore, it is anticipated that this method will be expanded to characterize additional fissile nuclides, utilize various irradiation sources, and account for increasingly complex sample matrices.« less

  12. Comparative measurement of prompt fission γ -ray emission from fast-neutron-induced fission of 235U and 238U

    NASA Astrophysics Data System (ADS)

    Lebois, M.; Wilson, J. N.; Halipré, P.; Oberstedt, A.; Oberstedt, S.; Marini, P.; Schmitt, C.; Rose, S. J.; Siem, S.; Fallot, M.; Porta, A.; Zakari, A.-A.

    2015-09-01

    Prompt fission γ -ray (PFG) spectra have been measured in a recent experiment with the novel directional fast-neutron source LICORNE at the ALTO facility of the IPN Orsay. These first results from the facility involve the comparative measurement of prompt γ emission in fast-neutron-induced fission of 235U and 238U . Characteristics such as γ multiplicity and total and average radiation energy are determined in terms of ratios between the two systems. Additionally, the average photon energies were determined and compared with recent data on thermal-neutron-induced fission of 235U . PFG spectra are shown to be similar within the precision of the present measurement, suggesting that the extra incident energy does not significantly impact the energy released by prompt γ rays. The origins of some small differences, depending on either the incident energy or the target mass, are discussed. This study demonstrates the potential of the present approach, combining an innovative neutron source and new-generation detectors, for fundamental and applied research on fission in the near future.

  13. Mass Yields and Average Total Kinetic Energy Release in Fission for 235U, 238U, and 239Pu

    NASA Astrophysics Data System (ADS)

    Duke, Dana

    2015-10-01

    Mass yield distributions and average total kinetic energy (TKE) in neutron induced fission of 235U, 238U, and 239Pu targets were measured with a gridded ionization chamber. Despite decades of fission research, our understanding of how fragment mass yields and TKE depend on incident neutron energy is limited, especially at higher energies (above 5-10 MeV). Improved accuracy in these quantities is important for nuclear technology as it enhances our simulation capabilities and increases the confidence in diagnostic tools. The data can also guide and validate theoretical fission models where the correlation between the fragment mass and TKE is of particular value for constraining models. The Los Alamos Neutron Science Center - Weapons Neutron Research (LANSCE - WNR) provides a neutron beam with energies from thermal to hundreds of MeV, well-suited for filling in the gaps in existing data and exploring fission behavior in the fast neutron region. The results of the studies on target nuclei 235U, 238U, and 239Pu will be presented with a focus on exploring data trends as a function of neutron energy from thermal through 30 MeV. Results indicate clear evidence of structure due to multi-chance fission in the TKE . LA-UR-15-24761.

  14. Fission Product Yields for 14 MeV Neutrons on 235U, 238U and 239Pu

    NASA Astrophysics Data System (ADS)

    Mac Innes, M.; Chadwick, M. B.; Kawano, T.

    2011-12-01

    We report cumulative fission product yields (FPY) measured at Los Alamos for 14 MeV neutrons on 235U, 238U and 239Pu. The results are from historical measurements made in the 1950s-1970s, not previously available in the peer reviewed literature, although an early version of the data was reported in the Ford and Norris review. The results are compared with other measurements and with the ENDF/B-VI England and Rider evaluation. Compared to the Laurec (CEA) data and to ENDF/B-VI evaluation, good agreement is seen for 235U and 238U, but our FPYs are generally higher for 239Pu. The reason for the higher plutonium FPYs compared to earlier Los Alamos assessments reported by Ford and Norris is that we update the measured values to use modern nuclear data, and in particular the 14 MeV 239Pu fission cross section is now known to be 15-20% lower than the value assumed in the 1950s, and therefore our assessed number of fissions in the plutonium sample is correspondingly lower. Our results are in excellent agreement with absolute FPY measurements by Nethaway (1971), although Nethaway later renormalized his data down by 9% having hypothesized that he had a normalization error. The new ENDF/B-VII.1 14 MeV FPY evaluation is in good agreement with our data.

  15. The use of k0-NAA for the determination of the n( 235U)/ n( 238U) isotopic ratio in samples containing uranium

    NASA Astrophysics Data System (ADS)

    Farina Arboccò, F.; Vermaercke, P.; Sneyers, L.; Soares Leal, A.; Gonçalves Bouças, J.

    2010-10-01

    In the analysis of rare earth elements in samples containing uranium by k0-neutron activation analysis fission of 235U was considered an undesired phenomenon until the "fission k0-factors" were introduced to account for natural-U fission interferences. In this work, by using a reverse perspective of the problem, the observed 235U-fission and 238U activation products (along with the k0-factors) were used to obtain information about the n( 235U)/ n( 238U) isotopic ratio in the samples. The relevant formulae and data-filtering algorithm were implemented in a home-made computer software, allowing automated evaluation and selection of unbiased data. Two radioisotopes ( 131I and 140La) were demonstrated to be reliable candidates for n( 235U)/ n( 238U) determination in environmental samples. The accuracy of this method was determined using several isotopic standards varying from a depleted to a highly enriched 235U content. An overall 2.31±0.03% overestimation of the isotopic ratio was observed (within 95% confidence level). Definition: n(X) refers to the isotopic abundance of isotope X

  16. 206Pb-230Th-234U-238U and 207Pb-235U geochronology of Quaternary opal, Yucca Mountain, Nevada

    USGS Publications Warehouse

    Neymark, Leonid A.; Amelin, Yuri V.; Paces, James B.

    2000-01-01

    U–Th–Pb isotopic systems have been studied in submillimeter-thick outermost layers of Quaternary opal occurring in calcite–silica fracture and cavity coatings within Tertiary tuffs at Yucca Mountain, Nevada, USA. These coatings preserve a record of paleohydrologic conditions at this site, which is being evaluated as a potential high-level nuclear waste repository. The opal precipitated from groundwater is variably enriched in 234U (measured 234U/238U activity ratio 1.124–6.179) and has high U (30–313 ppm), low Th (0.008–3.7 ppm), and low common Pb concentrations (measured 206Pb/204Pb up to 11,370). It has been demonstrated that the laboratory acid treatment used in this study to clean sample surfaces and to remove adherent calcite, did not disturb U–Th–Pb isotopic systems in opal. The opal ages calculated from 206Pb∗/238U and 207Pb∗/235U ratios display strong reverse discordance because of excess radiogenic 206Pb∗ derived from the elevated initial 234U. The data are best interpreted using projections of a new four-dimensional concordia diagram defined by 206Pb∗/238U, 207Pb∗/235U, 234U/238Uactivity, and 230Th/238Uactivity. Ages and initial 234U/238U activity ratios have been calculated using different projections of this diagram and tested for concordance. The data are discordant, that is observed 207Pb∗/235U ages of 170 ± 32 (2σ) to 1772 ± 40 ka are systematically older than 230Th/U ages of 34.1 ± 0.6 to 452 ± 32 ka. The age discordance is not a result of migration of uranium and its decay products under the open system conditions, but a consequence of noninstantaneous growth of opal. Combined U–Pb and 230Th/U ages support the model of slow mineral deposition at the rates of millimeters per million years resulting in layering on a scale too fine for mechanical sampling. In this case, U–Pb ages provide more accurate estimates of the average age for mixed multiage samples than 230Th/U ages, because ages based on shorter

  17. Determination of the 233Pa(n, f) reaction cross section from 0.5 to 10 MeV neutron energy using the transfer reaction 232Th( 3He, p) 234Pa

    NASA Astrophysics Data System (ADS)

    Petit, M.; Aiche, M.; Barreau, G.; Boyer, S.; Carjan, N.; Czajkowski, S.; Dassié, D.; Grosjean, C.; Guiral, A.; Haas, B.; Karamanis, D.; Misicu, S.; Rizea, C.; Saintamon, F.; Andriamonje, S.; Bouchez, E.; Gunsing, F.; Hurstel, A.; Lecoz, Y.; Lucas, R.; Theisen, Ch.; Billebaud, A.; Perrot, L.; Bauge, E.

    2004-05-01

    The fission probability distributions of 232, 233, 234 Pa and 231Th have been measured up to an excitation energy of 15 MeV, using the transfer reactions 232Th( 3He, t) 232Pa, 232Th( 3He, d) 233Pa, 232Th( 3He, p) 234Pa and 232Th( 3He, 4He) 231Th. From these measurements, the neutron induced fission cross sections of 231Pa, 233Pa and 230Th have been determined from the product of the fission probabilities of 232Pa, 233Pa and 231Th respectively with the calculated compound nucleus formation cross sections in the 231Pa+n, 233Pa+n and 230Th+n reactions. The validity of the applied method has been successfully tested with the existing neutron induced fission cross sections of 230Th and 231Pa. Special emphasis is put on the 233Pa(n, f) reaction which is of importance for thorium fueled nuclear reactors. Based on a statistical model analysis of the neutron induced fission cross section as a function of neutron energy, it has been possible to determine the barrier parameters of the 234Pa fissioning nucleus. Cross sections for the compound nucleus inelastic scatttering 233Pa(n, n') and radiative capture 233Pa(n, γ) reactions have also been calculated and compared with recent evaluations.

  18. Transfer Rates of 238U and 232Th for E. globulus, A. mearnsii, H. filipendula and Hazardous Effects of the Usage of Medicinal Plants From Around Gold Mine Dump Environs

    PubMed Central

    Tshivhase, Victor M.; Njinga, Raymond L.; Mathuthu, Manny; Dlamini, Thulani C.

    2015-01-01

    Medicinal plant consumption can be a source of human exposure to radioactive elements such as 238U and 232Th, which can lead to internal radiation doses. The uptake of 238U and 232Th from soils to the leaf samples of three different medicinal plant species (Eucalyptus globulus, Acacia mearnsii and Hyparrhenia filipendula) from the purlieu of the Princess gold mine dump, an abandoned contaminated tailings storage site (TSS), located at longitude 27°55′00″E and latitude 26°09′30″S in Davidsonville (Roodepoort, west of Johannesburg, South Africa) was measured. This was done using ICP-MS spectrometry and substantial differences were observed in the soil-plant transfer factor (TF) values between these radionuclides. The plant species E. globulus exhibited the highest uptake of 238U, with an average TF of 3.97, while that of H. filipendula was 0.01 and the lowest TF of 0.15 × 10−2 was measured for A. mearnsii. However, in the case of 232Th, the highest average TF was observed for A. mearnsii (0.29), followed by E. globulus (0.10) and lowest was measured for H. filipendula (0.27 × 10−2). The ratio of TF average value i.e., 238U to 232Th in the soil-plant leaves was 38.05 for E. globulus, 0.01 for A. mearnsii and 4.38 for H. filipendula. PMID:26690462

  19. Analysis of Fragment Mass Distribution in Asymmetric Area at Fission of {sup 235}U Induced by Thermal Neutrons

    SciTech Connect

    Pikul, V.P.; Koblik, Yu.N.; Khugaev, A.V.; Yuldashev, B.S.; Jovliev, U.Yu.; Muminov, A.I.; Pavliy, K.V.; Nasirov, A.K.

    2005-02-01

    The fragment mass yields in fission of {sup 235}U induced by thermal neutrons for A=145 - 160 and E{sub K}=50 - 75 MeV were measured using a mass spectrometer. The fine structure is observed at A=153, 154 and E{sub K}=50 - 60 MeV. The obtained results were described in the framework of a model based on the dinuclear system concept. The analyzed correlation between the total kinetic energy and mass distribution of fission fragments is connected with the shell structure of the formed fragments of fission. From this correlation and the time dependence of the calculated mass distribution of the binary reaction products, one can conclude that the descent time from a saddle point to a scission point for the more deformed fragments is longer than that for fragments of more compact shape.

  20. Study of Photon Strength Function of Actinides: the Case of (235)U, (238)Np and (241)Pu

    SciTech Connect

    Guerrero, C.; Koehler, Paul Edward; N_TOF collaboration,

    2011-01-01

    The decay from excited levels in medium and heavy nuclei can be described in a statistical approach by means of Photon Strength Functions and Level Density distributions. The study of electromagnetic cascades following neutron capture based on the use of high efficiency detectors has been shown to be well suited for probing the properties of the Photon Strength Function of heavy (high level density) and/or radioactive (high background) nuclei. In this work we have investigated for the first time the validity of the recommended PSF of actinides, in particular {sup 235}U, {sup 238}Np and {sup 241}Pu. Our study includes the search for resonance structures in the PSF below Sn and draws conclusions regarding their existence and their characteristics in terms of energy, width and electromagnetic nature.

  1. Fission Product Yield Study of 235U, 238U and 239Pu Using Dual-Fission Ionization Chambers

    NASA Astrophysics Data System (ADS)

    Bhatia, C.; Fallin, B.; Howell, C.; Tornow, W.; Gooden, M.; Kelley, J.; Arnold, C.; Bond, E.; Bredeweg, T.; Fowler, M.; Moody, W.; Rundberg, R.; Rusev, G.; Vieira, D.; Wilhelmy, J.; Becker, J.; Macri, R.; Ryan, C.; Sheets, S.; Stoyer, M.; Tonchev, A.

    2014-05-01

    To resolve long-standing differences between LANL and LLNL regarding the correct fission basis for analysis of nuclear test data [M.B. Chadwick et al., Nucl. Data Sheets 111, 2891 (2010); H. Selby et al., Nucl. Data Sheets 111, 2891 (2010)], a collaboration between TUNL/LANL/LLNL has been established to perform high-precision measurements of neutron induced fission product yields. The main goal is to make a definitive statement about the energy dependence of the fission yields to an accuracy better than 2-3% between 1 and 15 MeV, where experimental data are very scarce. At TUNL, we have completed the design, fabrication and testing of three dual-fission chambers dedicated to 235U, 238U, and 239Pu. The dual-fission chambers were used to make measurements of the fission product activity relative to the total fission rate, as well as for high-precision absolute fission yield measurements. The activation method was employed, utilizing the mono-energetic neutron beams available at TUNL. Neutrons of 4.6, 9.0, and 14.5 MeV were produced via the 2H(d,n)3He reaction, and for neutrons at 14.8 MeV, the 3H(d,n)4He reaction was used. After activation, the induced γ-ray activity of the fission products was measured for two months using high-resolution HPGe detectors in a low-background environment. Results for the yield of seven fission fragments of 235U, 238U, and 239Pu and a comparison to available data at other energies are reported. For the first time results are available for neutron energies between 2 and 14 MeV.

  2. IUPAC-IUGS status report on the half-lives of 238U, 235U and 234U

    NASA Astrophysics Data System (ADS)

    Villa, I. M.; Bonardi, M. L.; De Bièvre, P.; Holden, N. E.; Renne, P. R.

    2016-01-01

    The current state of knowledge on the half-lives of the long-lived U radionuclides has been reviewed by the IUPAC-IUGS joint Task Group "Isotopes in Geosciences". 238U is assigned a half-life of (4.4683 ± 0.0096) Ga, i.e. a decay constant λ238 = (0.155125 ± 0.000333) Ga-1. The coverage factor is k = 2 for this and all other estimates presented here. The 238U half-life can be used as a reference for the half-lives/decay constants of all other isotopic geochronometers. A revision of the half-life of 235U based on intercomparison of natural geological samples is premature. The improved repeatability of mass spectrometric measurements has revealed Type B uncertainties that had been dismissed as subordinate in the past. The combined uncertainty of these as yet incompletely charted and quantified sources of Type B uncertainty may be no smaller than the currently accepted uncertainty of the α counting experiments. A provisional value for the 234U half-life can be calculated with the assumption of secular equilibrium in the analyzed natural samples. This assumption has not yet been verified independently and its metrological traceability appears sub-optimum. A Type B evaluation suggests that the ca. 0.17% offset between the N(234U)/N(238U) number-ratios of the natural samples used to estimate the 235U half-life and those of the four samples used to estimate the 234U half-life should be compounded into the standard measurement uncertainty of the latter. The resulting provisional uncertainty interval (k = 2) for the 234U half-life is (244.55-247.77) ka, corresponding to λ234 = (2.8203-2.8344) Ma-1.

  3. Multilevel fitting of {sup 235}U resonance data sensitive to Bohr-and Brosa-fission channels

    SciTech Connect

    Moore, M.S.

    1995-05-01

    The recent determination of the K, J dependence of the neutron induced fission cross section of {sup 235}U by the Dubna group has led to a renewed interest in the mechanism of fission from saddle to scission. The K quantum numbers designate the so-called Bohr fission channels, which describe the fission properties at the saddle point. Certain other fission properties, e.g., the fragment mass and kinetic-energy distribution, are related to the properties of the scission point. The neutron energy dependence of the fragment kinetic energies has been measured by Hambsch et al., who analyzed their data according to a channel description of Brosa et al. How these two channel descriptions, the saddle-point Bohr channels and the scission-point Brosa channels, relate to one another is an open question, and is the subject matter of the present paper. We use the correlation coefficient between various data sets, in which variations are reported from resonance to resonance, as a measure of both-the statistical reliability of the data and of the degree to which different scission variables relate to different Bohr channels. We have carried out an adjustment of the ENDF/B-VI multilevel evaluation of the fission cross section of {sup 235}U, one that provides a reasonably good fit to the energy dependence of the fission, capture, and total cross sections below 100 eV, and to the Bohr-channel structure deduced from an earlier measurement by Pattenden and Postma. We have also further explored the possibility of describing the data of Hambsch et al. in the Brosa-channel framework with the same set of fission-width vectors, only in a different reference system. While this approach shows promise, it is clear that better data are also needed for the neutron energy variation of the scission-point variables.

  4. Reactive transport of uranium in a groundwater bioreduction study: Insights from high-temporal resolution 238U/235U data

    NASA Astrophysics Data System (ADS)

    Shiel, A. E.; Johnson, T. M.; Lundstrom, C. C.; Laubach, P. G.; Long, P. E.; Williams, K. H.

    2016-08-01

    We conducted a detailed investigation of U isotopes in conjunction with a broad geochemical investigation during field-scale biostimulation and desorption experiments. This investigation was carried out in the uranium-contaminated alluvial aquifer of the Rifle field research site. In this well-characterized setting, a more comprehensive understanding of U isotope geochemistry is possible. Our results indicate that U isotope fractionation is consistently observed across multiple experiments at the Rifle site. Microbially-mediated reduction is suggested to account for most or all of the observed fractionation as abiotic reduction has been demonstrated to impart much smaller, often near-zero, isotopic fractionation or isotopic fractionation in the opposite direction. Data from some time intervals are consistent with a simple model for transport and U(VI) reduction, where the fractionation factor (ε = +0.65‰ to +0.85‰) is consistent with experimental studies. However, during other time intervals the observed patterns in our data indicate the importance of other processes in governing U concentrations and 238U/235U ratios. For instance, we demonstrate that departures from Rayleigh behavior in groundwater systems arise from the presence of adsorbed species. We also show that isotope data are sensitive to the onset of oxidation after biostimulation ends, even in the case where reduction continues to remove contaminant uranium downstream. Our study and the described conceptual model support the use of 238U/235U ratios as a tool for evaluating the efficacy of biostimulation and potentially other remedial strategies employed at Rifle and other uranium-contaminated sites.

  5. 238U series isotopes and 232Th in carbonates and black shales from the Lesser Himalaya: implications to dissolved uranium abundances in Ganga-Indus source waters.

    PubMed

    Singh, S K; Dalai, Tarun K; Krishnaswami, S

    2003-01-01

    238U and (232)Th concentrations and the extent of (238)U-(234)U-(230)Th radioactive equilibrium have been measured in a suite of Precambrian carbonates and black shales from the Lesser Himalaya. These measurements were made to determine their abundances in these deposits, their contributions to dissolved uranium budget of the headwaters of the Ganga and the Indus in the Himalaya and to assess the impact of weathering on (238)U-(234)U-(230)Th radioactive equilibrium in them. (238)U concentrations in Precambrian carbonates range from 0.06 to 2.07 microg g(-1). The 'mean' U/Ca in these carbonates is 2.9 ng U mg(-1) Ca. This ratio, coupled with the assumption that all Ca in the Ganga-Indus headwaters is of carbonate origin and that U and Ca behave conservatively in rivers after their release from carbonates, provides an upper limit on the U contribution from these carbonates, to be a few percent of dissolved uranium in rivers. There are, however, a few streams with low uranium concentrations, for which the carbonate contribution could be much higher. These results suggest that Precambrian carbonates make only minor contributions to the uranium budget of the Ganga-Indus headwaters in the Himalaya on a basin wide scale, however, they could be important for particular streams. Similar estimates of silicate contribution to uranium budget of these rivers using U/Na in silicates and Na* (Na corrected for cyclic and halite contributions) in river waters show that silicates can contribute significantly (approximately 40% on average) to their U balance. If, however, much of the uranium in these silicates is associated with weathering resistant minerals, then the estimated silicate uranium component would be upper limits. Uranium concentration in black shales averages about 37 microg g(-1). Based on this concentration, supply of U from at least approximately 50 mg of black shales per liter of river water is needed to balance the average river water U concentration, 1.7 microg L

  6. Process for producing enriched uranium having a {sup 235}U content of at least 4 wt. % via combination of a gaseous diffusion process and an atomic vapor laser isotope separation process to eliminate uranium hexafluoride tails storage

    DOEpatents

    Horton, J.A.; Hayden, H.W. Jr.

    1995-05-30

    An uranium enrichment process capable of producing an enriched uranium, having a {sup 235}U content greater than about 4 wt. %, is disclosed which will consume less energy and produce metallic uranium tails having a lower {sup 235}U content than the tails normally produced in a gaseous diffusion separation process and, therefore, eliminate UF{sub 6} tails storage and sharply reduce fluorine use. The uranium enrichment process comprises feeding metallic uranium into an atomic vapor laser isotope separation process to produce an enriched metallic uranium isotopic mixture having a {sup 235} U content of at least about 2 wt. % and a metallic uranium residue containing from about 0.1 wt. % to about 0.2 wt. % {sup 235} U; fluorinating this enriched metallic uranium isotopic mixture to form UF{sub 6}; processing the resultant isotopic mixture of UF{sub 6} in a gaseous diffusion process to produce a final enriched uranium product having a {sup 235}U content of at least 4 wt. %, and up to 93.5 wt. % or higher, of the total uranium content of the product, and a low {sup 235}U content UF{sub 6} having a {sup 235}U content of about 0.71 wt. % of the total uranium content of the low {sup 235}U content UF{sub 6}; and converting this low {sup 235}U content UF{sub 6} to metallic uranium for recycle to the atomic vapor laser isotope separation process. 4 figs.

  7. Process for producing enriched uranium having a .sup.235 U content of at least 4 wt. % via combination of a gaseous diffusion process and an atomic vapor laser isotope separation process to eliminate uranium hexafluoride tails storage

    DOEpatents

    Horton, James A.; Hayden, Jr., Howard W.

    1995-01-01

    An uranium enrichment process capable of producing an enriched uranium, having a .sup.235 U content greater than about 4 wt. %, is disclosed which will consume less energy and produce metallic uranium tails having a lower .sup.235 U content than the tails normally produced in a gaseous diffusion separation process and, therefore, eliminate UF.sub.6 tails storage and sharply reduce fluorine use. The uranium enrichment process comprises feeding metallic uranium into an atomic vapor laser isotope separation process to produce an enriched metallic uranium isotopic mixture having a .sup.235 U content of at least about 2 wt. % and a metallic uranium residue containing from about 0.1 wt. % to about 0.2 wt. % .sup.235 U; fluorinating this enriched metallic uranium isotopic mixture to form UF.sub.6 ; processing the resultant isotopic mixture of UF.sub.6 in a gaseous diffusion process to produce a final enriched uranium product having a .sup.235 U content of at least 4 wt. %, and up to 93.5 wt. % or higher, of the total uranium content of the product, and a low .sup.235 U content UF.sub.6 having a .sup.235 U content of about 0.71 wt. % of the total uranium content of the low .sup.235 U content UF.sub.6 ; and converting this low .sup.235 U content UF.sub.6 to metallic uranium for recycle to the atomic vapor laser isotope separation process.

  8. Influence of different data tables on neutron induced reactions in quasi-infinite 238U and 232Th targets irradiated by protons with relativistic energy

    NASA Astrophysics Data System (ADS)

    Zhivkov, P.; Stoyanov, Ch; Tyutyunnikov, S.; Furman, W.

    2016-06-01

    The last decade saw the emergence of various theoretical analysis and developments of ADS (Accelerator Driving System). Different transport codes, nuclear models and nuclear cross sections have been used to predict and estimate the properties of ADS. The energy of the proton beam is supposed to range between 1 and 1.5 GeV, but some analyses suggest higher energy - up to 10 GeV. The recent papers examine the influence of the nuclear models on neutron induced reactions (n,f), (n,g), (n,xn), (n,el.) and (n,inel.). The experimental set-ups and the presumable ADS constructions consist of thousands of segments and details for example project Myrrha, Belgum [1]. The calculation of the above reactions depends on the neutron spectrum in each segment. There is a considerable difference in the size of these segments in ADS, which makes the estimation of the influence of the nuclear models and the cross sections on the integral number of neutron induced reactions more difficult. This article considers the influence of different cross section data tables on neutron induced reactions in 238U or 232Th targets. One nuclear model describing the high energy part of the nuclear interaction and various cross section data tagble (ENDF, ENDL, TENDL2014 and etc.) are used. All particles generated in the nuclear interaction process deposit their energy in the target volume. MCNP 6.1 transport code was used.

  9. SAS2H input for computing core activities of 4.5, 5.0, and 5.5 weight % {sup 235}U fuel for Sequoyah Nuclear Plant

    SciTech Connect

    Hermann, O.W.

    1994-08-01

    Sequoyah Nuclear Plant core activities at initial fuel enrichments of 4.5, 5.0, and 5.5 wt% {sup 235}U, required in nuclear safety evaluations, were computed by the SAS2H analysis sequence and the ORIGEN-S code within the SCALE-4.2 code system.

  10. Uranium 238U/235U isotope ratios as indicators of reduction: results from an in situ biostimulation experiment at Rifle, Colorado, U.S.A.

    PubMed

    Bopp, Charles John; Lundstrom, Craig C; Johnson, Thomas M; Sanford, Robert A; Long, Philip E; Williams, Kenneth H

    2010-08-01

    The attenuation of groundwater contamination via chemical reaction is traditionally evaluated by monitoring contaminant concentration through time. However, this method can be confounded by common transport processes (e.g., dilution, sorption). Isotopic techniques bypass the limits of concentration methods, and so may provide improved accuracy in determining the extent of reaction. We apply measurements of 238U/235U to a U bioremediation field experiment at the Rifle Integrated Field Research Challenge Site in Rifle, Colorado. An array of monitoring and injection wells was installed on a 100 m2 plot where U(VI) contamination was present in the groundwater. Acetate-amended groundwater was injected along an up-gradient gallery to encourage the growth of dissimilatory metal reducing bacteria (e.g., Geobacter species). During amendment, U concentration dropped by an order of magnitude in the experiment plot. We measured 238U/235U in samples from one monitoring well by MC-ICP-MS using a double isotope tracer method. A significant approximately 1.00 per thousand decrease in 238U/235U occurred in the groundwater as U(VI) concentration decreased. The relationship between 238U/235U and concentration corresponds approximately to a Rayleigh distillation curve with an effective fractionation factor (alpha) of 1.00046. We attribute the observed U isotope fractionation to a nuclear field shift effect during enzymatic reduction of U(VI)(aq) to U(IV)(s).

  11. Towards A Modern Calibration Of The 238U/235U Paleoredox Proxy: Apparent Uranium Isotope Fractionation Factor During U(VI)-U(IV) Reduction In The Black Sea

    NASA Astrophysics Data System (ADS)

    Rolison, J. M.; Stirling, C. H.; Middag, R.; Rijkenberg, M. J. A.; De Baar, H. J. W.

    2015-12-01

    The isotopic compositions of redox-sensitive metals, including uranium (U), in marine sediments have recently emerged as powerful diagnostic tracers of the redox state of the ancient ocean-atmosphere system. Interpretation of sedimentary isotopic information requires a thorough understating of the environmental controls on isotopic fractionation in modern anoxic environments before being applied to the paleo-record. In this study, the relationship between ocean anoxia and the isotopic fractionation of U was investigated in the water column and sediments of the Black Sea. The Black Sea is the world's largest anoxic basin and significant removal of U from the water column and high U accumulation rates in modern underlying sediments have been documented. Removal of U from the water column occurs during the redox transition of soluble U(VI) to relatively insoluble U(IV). The primary results of this study are two-fold. First, significant 238U/235U fractionation was observed in the water column of the Black Sea, suggesting the reduction of U induces 238U/235U fractionation with the preferential removal of 238U from the aqueous phase. Second, the 238U/235U of underlying sediments is related to the water column through the isotope fractionation factor of the reduction reaction but is influenced by mass transport processes. These results provide important constraints on the use of 238U/235U as a proxy of the redox state of ancient oceans.

  12. Investigating Uranium Mobility Using Stable Isotope Partitioning of 238U/235U and a Reactive Transport Model

    NASA Astrophysics Data System (ADS)

    Bizjack, M.; Johnson, T. M.; Druhan, J. L.; Shiel, A. E.

    2015-12-01

    We report a numerical reactive transport model which explicitly incorporates the effectively stable isotopes of uranium (U) and the factors that influence their partitioning in bioactive systems. The model reproduces trends observed in U isotope ratios and concentration measurements from a field experiment, thereby improving interpretations of U isotope ratios as a tracer for U reactive transport. A major factor contributing to U storage and transport is its redox state, which is commonly influenced by the availability of organic carbon to support metal-reducing microbial communities. Both laboratory and field experiments have demonstrated that biogenic reduction of U(VI) fractionates the stable isotope ratio 238U/235U, producing an isotopically heavy solid U(IV) product. It has also been shown that other common reactive transport processes involving U do not fractionate isotopes to a consistently measurable level, which suggests the capacity to quantify the extent of bioreduction occurring in groundwater containing U using 238U/235U ratios. A recent study of a U bioremediation experiment at the Rifle IFRC site (Colorado, USA) applied Rayleigh distillation models to quantify U stable isotope fractionation observed during acetate amendment. The application of these simplified models were fit to the observations only by invoking a "memory-effect," or a constant source of low-concentration, unfractionated U(VI). In order to more accurately interpret the measured U isotope ratios, we present a multi-component reactive transport model using the CrunchTope software. This approach is capable of quantifying the cycling and partitioning of individual U isotopes through a realistic network of transport and reaction pathways including reduction, oxidation, and microbial growth. The model incorporates physical heterogeneity of the aquifer sediments through zones of decreased permeability, which replicate the observed bromide tracer, major ion chemistry, U concentration, and U

  13. High-spin structure in 40K

    NASA Astrophysics Data System (ADS)

    Söderström, P.-A.; Recchia, F.; Nyberg, J.; Gadea, A.; Lenzi, S. M.; Poves, A.; Ataç, A.; Aydin, S.; Bazzacco, D.; Bednarczyk, P.; Bellato, M.; Birkenbach, B.; Bortolato, D.; Boston, A. J.; Boston, H. C.; Bruyneel, B.; Bucurescu, D.; Calore, E.; Cederwall, B.; Charles, L.; Chavas, J.; Colosimo, S.; Crespi, F. C. L.; Cullen, D. M.; de Angelis, G.; Désesquelles, P.; Dosme, N.; Duchêne, G.; Eberth, J.; Farnea, E.; Filmer, F.; Görgen, A.; Gottardo, A.; Grębosz, J.; Gulmini, M.; Hess, H.; Hughes, T. A.; Jaworski, G.; Jolie, J.; Joshi, P.; Judson, D. S.; Jungclaus, A.; Karkour, N.; Karolak, M.; Kempley, R. S.; Khaplanov, A.; Korten, W.; Ljungvall, J.; Lunardi, S.; Maj, A.; Maron, G.; Męczyński, W.; Menegazzo, R.; Mengoni, D.; Michelagnoli, C.; Molini, P.; Napoli, D. R.; Nolan, P. J.; Norman, M.; Obertelli, A.; Podolyak, Zs.; Pullia, A.; Quintana, B.; Redon, N.; Regan, P. H.; Reiter, P.; Robinson, A. P.; Şahin, E.; Simpson, J.; Salsac, M. D.; Smith, J. F.; Stézowski, O.; Theisen, Ch.; Tonev, D.; Unsworth, C.; Ur, C. A.; Valiente-Dobón, J. J.; Wiens, A.

    2012-11-01

    High-spin states of 40K have been populated in the fusion-evaporation reaction 12C(30Si,np)40K and studied by means of γ-ray spectroscopy techniques using one triple-cluster detector of the Advanced Gamma Tracking Array at the Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro. Several states with excitation energy up to 8 MeV and spin up to 10- have been discovered. These states are discussed in terms of J=3 and T=0 neutron-proton hole pairs. Shell-model calculations in a large model space have shown good agreement with the experimental data for most of the energy levels. The evolution of the structure of this nucleus is here studied as a function of excitation energy and angular momentum.

  14. Determination of Nuclear Charge Distributions of Fission Fragments from ^{235}U (n_th, f) with Calorimetric Low Temperature Detectors

    NASA Astrophysics Data System (ADS)

    Grabitz, P.; Andrianov, V.; Bishop, S.; Blanc, A.; Dubey, S.; Echler, A.; Egelhof, P.; Faust, H.; Gönnenwein, F.; Gomez-Guzman, J. M.; Köster, U.; Kraft-Bermuth, S.; Mutterer, M.; Scholz, P.; Stolte, S.

    2016-08-01

    Calorimetric low temperature detectors (CLTD's) for heavy-ion detection have been combined with the LOHENGRIN recoil separator at the ILL Grenoble for the determination of nuclear charge distributions of fission fragments produced by thermal neutron-induced fission of ^{235}U. The LOHENGRIN spectrometer separates fission fragments according to their mass-to-ionic-charge ratio and their kinetic energy, but has no selectivity with respect to nuclear charges Z. For the separation of the nuclear charges, one can exploit the nuclear charge-dependent energy loss of the fragments passing through an energy degrader foil (absorber method). This separation requires detector systems with high energy resolution and negligible pulse height defect, as well as degrader foils which are optimized with respect to thickness, homogeneity, and energy loss straggling. In the present, contribution results of test measurements at the Maier Leibnitz tandem accelerator facility in Munich with ^{109}Ag and ^{127}I beams with the aim to determine the most suitable degrader material, as well as measurements at the Institut Laue-Langevin will be presented. These include a systematic study of the quality of Z-separation of fission fragments in the mass range 82le A le 132 and a systematic measurement of ^{92}Rb fission yields, as well as investigations of fission yields toward the symmetry region.

  15. Yields of short-lived fission products produced following {sup 235}U(n{sub th},f)

    SciTech Connect

    Tipnis, S.V.; Campbell, J.M.; Couchell, G.P.; Li, S.; Nguyen, H.V.; Pullen, D.J.; Schier, W.A.; Seabury, E.H.; England, T.R.

    1998-08-01

    Measurements of gamma-ray spectra, following the thermal neutron fission of {sup 235}U have been made using a high purity germanium detector at the University of Massachusetts Lowell (UML) Van de Graaff facility. The gamma spectra were measured at delay times ranging from 0.2 s to nearly 10thinsp000 s following the rapid transfer of the fission fragments with a helium-jet system. On the basis of the known gamma transitions, forty isotopes have been identified and studied. By measuring the relative intensities of these transitions, the relative yields of the various precursor nuclides have been calculated. The results are compared with the recommended values listed in the ENDF/B-VI fission product data base (for the lifetimes and the relative yields) and those published in the Nuclear Data Sheets (for the beta branching ratios). This information is particularly useful for the cases of short-lived fission products with lifetimes of the order of fractions of a second or a few seconds. Independent yields of many of these isotopes have rather large uncertainties, some of which have been reduced by the present study. {copyright} {ital 1998} {ital The American Physical Society}

  16. Preliminary results on ^241,243Am and ^235U (n,γ) cross sections measured at DANCE

    NASA Astrophysics Data System (ADS)

    Jandel, M.; Bredeweg, T. A.; Fowler, M. M.; Bond, E. M.; O'Donnell, J. M.; Reifarth, R.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.; Macri, R. A.; Wu, C.-Y.; Becker, J. A.

    2006-10-01

    The Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory (LANL) was used for neutron capture cross sections measurements. Its high granularity of 160 BaF2 detectors allows for highly efficient detection of prompt gamma-rays following a neutron capture. DANCE is located on the 20.26 m neutron flight path 14 at the Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos Neutron Science Center (LANSCE). The moderated production target provides neutrons in the 0.02 eV - 500 keV energy range. An analysis of neutron capture measurements on ^241,243Am and ^235U targets will be presented. The experiments were carried out using a customized Parallel-Plate Avalanche Counter (PPAC) detector installed in the center of the DANCE array. The PPAC was used as a fission-tagging detector to separate (n,γ) from (n,fission) events. Preliminary results of (n,γ) cross sections will be presented and compared with the available evaluated data for neutron energies from 0.02 eV to 1 keV. Additional neutron capture measurements with DANCE will be briefly discussed.

  17. On monitoring anthropogenic airborne uranium concentrations and (235)U/(238)U isotopic ratio by Lichen - bio-indicator technique.

    PubMed

    Golubev, A V; Golubeva, V N; Krylov, N G; Kuznetsova, V F; Mavrin, S V; Aleinikov, A Yu; Hoppes, W G; Surano, K A

    2005-01-01

    Lichens are widely used to assess the atmospheric pollution by heavy metals and radionuclides. However, few studies are available in publications on using lichens to qualitatively assess the atmospheric pollution levels. The paper presents research results applying epiphytic lichens as bio-monitors of quantitative atmospheric contamination with uranium. The observations were conducted during 2.5 years in the natural environment. Two experimental sites were used: one in the vicinity of a uranium contamination source, the other one - at a sufficient distance away to represent the background conditions. Air and lichens were sampled at both sites monthly. Epiphytic lichens Hypogimnia physodes were used as bio-indicators. Lichen samples were taken from various trees at about 1.5m from the ground. Air was sampled with filters at sampling stations. The uranium content in lichen and air samples as well as isotopic mass ratios (235)U/(238)U were measured by mass-spectrometer technique after uranium pre-extraction. Measured content of uranium were 1.45 mgkg(-1) in lichen at 2.09 E-04 microgm(-3) in air and 0.106 mgkg(-1) in lichen at 1.13 E-05 microgm(-3) in air. The relationship of the uranium content in atmosphere and that in lichens was determined, C(AIR)=exp(1.1 x C(LICHEN)-12). The possibility of separate identification of natural and man-made uranium in lichens was demonstrated in principle.

  18. Calculation of the absolute detection efficiency of a moderated /sup 235/U neutron detector on the Tokamak Fusion Test Reactor

    SciTech Connect

    Ku, L.P.; Hendel, H.W.; Liew, S.L.

    1989-02-01

    Neutron transport simulations have been carried out to calculate the absolute detection efficiency of a moderated /sup 235/U neutron detector which is used on the TFTR as a part of the primary fission detector diagnostic system for measuring fusion power yields. Transport simulations provide a means by which the effects of variations in various shielding and geometrical parameters can be explored. These effects are difficult to study in calibration experiments. The calculational model, benchmarked against measurements, can be used to complement future detector calibrations, when the high level of radioactivity resulting from machine operation may severely restrict access to the tokamak. We present a coupled forward-adjoint algorithm, employing both the deterministic and Monte Carlo sampling methods, to model the neutron transport in the complex tokamak and detector geometries. Sensitivities of the detector response to the major and minor radii, and angular anisotropy of the neutron emission are discussed. A semi-empirical model based on matching the calculational results with a small set of experiments produces good agreement (+-15%) for a wide range of source energies and geometries. 20 refs., 6 figs., 4 tabs.

  19. Design of a high-flux epithermal neutron beam using 235U fission plates at the Brookhaven Medical Research Reactor.

    PubMed

    Liu, H B; Brugger, R M; Rorer, D C; Tichler, P R; Hu, J P

    1994-10-01

    Beams of epithermal neutrons are being used in the development of boron neutron capture therapy for cancer. This report describes a design study in which 235U fission plates and moderators are used to produce an epithermal neutron beam with higher intensity and better quality than the beam currently in use at the Brookhaven Medical Research Reactor (BMRR). Monte Carlo calculations are used to predict the neutron and gamma fluxes and absorbed doses produced by the proposed design. Neutron flux measurements at the present epithermal treatment facility (ETF) were made to verify and compare with the computed results where feasible. The calculations indicate that an epithermal neutron beam produced by a fission-plate converter could have an epithermal neutron intensity of 1.2 x 10(10) n/cm2.s and a fast neutron dose per epithermal neutron of 2.8 x 10(-11) cGy.cm2/nepi plus being forward directed. This beam would be built into the beam shutter of the ETF at the BMRR. The feasibility of remodeling the facility is discussed.

  20. Measurement of 238U and 232Th in Petrol, Gas-oil and Lubricant Samples by Using Nuclear Track Detectors and Resulting Radiation Doses to the Skin of Mechanic Workers.

    PubMed

    Misdaq, M A; Chaouqi, A; Ouguidi, J; Touti, R; Mortassim, A

    2015-10-01

    Workers in repair shops of vehicles (cars, buses, truck, etc.) clean carburetors, check fuel distribution, and perform oil changes and greasing. To explore the exposure pathway of (238)U and (232)Th and its decay products to the skin of mechanic workers, these radionuclides were measured inside petrol, gas-oil, and lubricant material samples by means of CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs), and corresponding annual committed equivalent doses to skin were determined. The maximum total equivalent effective dose to skin due to the (238)U and (232)Th series from the application of different petrol, gas-oil, and lubricant samples by mechanic workers was found equal to 1.2 mSv y(-1) cm(-2).

  1. Study of secondary neutron interactions with 232Th, 129I, and 127I nuclei with the uranium assembly “QUINTA” at 2, 4, and 8GeV deuteron beams of the JINR Nuclotron accelerator

    DOE PAGES

    Adam, J.; Chilap, V. V.; Furman, V. I.; Kadykov, M. G.; Khushvaktov, J.; Pronskikh, V. S.; Solnyshkin, A. A.; Stegailov, V. I.; Suchopar, M.; Tsoupko-Sitnikov, V. M.; et al

    2015-11-04

    The natural uranium assembly, “QUINTA”, was irradiated with 2, 4, and 8 GeV deuterons. The 232Th, 127I, and 129I samples have been exposed to secondary neutrons produced in the assembly at a 20-cm radial distance from the deuteron beam axis. The spectra of gamma rays emitted by the activated 232Th, 127I, and 129I samples have been analyzed and several tens of product nuclei have been identified. For each of those products, neutron-induced reaction rates have been determined. The transmutation power for the 129I samples is estimated. Furthermore, experimental results were compared to those calculated with well-known stochastic and deterministic codes.

  2. Measurement of 238U and 232Th in Petrol, Gas-oil and Lubricant Samples by Using Nuclear Track Detectors and Resulting Radiation Doses to the Skin of Mechanic Workers.

    PubMed

    Misdaq, M A; Chaouqi, A; Ouguidi, J; Touti, R; Mortassim, A

    2015-10-01

    Workers in repair shops of vehicles (cars, buses, truck, etc.) clean carburetors, check fuel distribution, and perform oil changes and greasing. To explore the exposure pathway of (238)U and (232)Th and its decay products to the skin of mechanic workers, these radionuclides were measured inside petrol, gas-oil, and lubricant material samples by means of CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs), and corresponding annual committed equivalent doses to skin were determined. The maximum total equivalent effective dose to skin due to the (238)U and (232)Th series from the application of different petrol, gas-oil, and lubricant samples by mechanic workers was found equal to 1.2 mSv y(-1) cm(-2). PMID:26313584

  3. Allanite from the El Muerto Pegmatite, Oaxaca, Mexico: A Potential New Standard for 232Th-208Pb Dating by LA-ICP-MS

    NASA Astrophysics Data System (ADS)

    Price, J.; Crowley, J. L.; Solari, L.; Prol-Ledesma, R.

    2012-12-01

    Allanite dating may be important to studies addressing tectonomagmatic evolution, provenance of monocyclic sediment, and mineral weathering. Obtaining accurate allanite ages by SIMS has been challenging and time-consuming due to the mineral's extreme chemical variability which often prevents finding adequately matrix-matched standards. Isotopic measurements by LA-ICP-MS minimize the need for standards of nearly identical composition to the unknown allanite being analyzed, and it is done relatively rapidly. Dating by LA-ICP-MS requires high quality standards for isotopic fractionation corrections. However, readily accessible and well characterized allanite standards are scarce. We investigated gemstone allanite from the El Muerto pegmatite, Oaxaca, Mexico, as a potential new geochronology standard for 232Th-208Pb allanite dating by LA-ICP-MS. Compositional homogeneity was thoroughly investigated by scanning and backscatter electron microscopy, cathodoluminescence, quantitative and qualitative energy dispersive x-ray spectroscopy, electron microprobe, and LA-ICP-MS. The possibility of metamictization was investigated by extensive X-ray diffraction analyses. The El Muerto allanite was U-Pb dated by ID-TIMS, with common Pb ratios determined from cogenetic K-feldspar by ID-TIMS and LA-MC-ICP-MS. Future work includes Th-Pb dating by ID-TIMS. The samples investigated are homogeneous with respect to major and trace elements. Major element compositional results are generally in agreement with published values, and no metamictization was identified despite the allanite being nearly 1 Ga. The only limitation of the El Muerto allanite is that it contains small, generally <100 μm, scarce inclusions of quartz, calciothorite, albite, calcite, and biotite. However, these grains are easily recognized and avoided during LA-ICP-MS analyses. Based on these results, the El Muerto allanite has the potential to serve as a standard for LA-ICP-MS dating.

  4. A precise 232Th-208Pb chronology of fine-grained monazite: Age of the Bayan Obo REE-Fe-Nb ore deposit, China

    USGS Publications Warehouse

    Wang, Jingyuan; Tatsumoto, M.; Li, X.; Premo, W.R.; Chao, E.C.T.

    1994-01-01

    We have obtained precise Th-Pb internal isochron ages on monazite and bastnaesite for the world's largest known rare earth elements (REE)-Fe-Nb ore deposit, the Bayan Obo of Inner Mongolia, China. The monazite samples, collected from the carbonate-hosted ore zone, contain extremely small amounts of uranium (less than 10 ppm) but up to 0.7% ThO2. Previous estimates of the age of mineralization ranged from 1.8 to 0.255 Ga. Magnetic fractions of monazite and bastnaesite samples (<60-??m size) showed large ranges in 232Th 204Pb values (900-400,000) and provided precise Th-Pb internal isochron ages for paragenetic monazite mineralization ranging from 555 to 398 Ma within a few percent error (0.8% for two samples). These results are the first indication that REE mineralization within the giant Bayan Obo ore deposit occurred over a long period of time. The initial lead isotopic compositions (low 206Pb 204Pb and high 208Pb 204Pb) and large negative ??{lunate}Nd values for Bayan Obo ore minerals indicate that the main source(s) for the ores was the lower crust which was depleted in uranium, but enriched in thorium and light rare earth elements for a long period of time. Zircon from a quartz monzonite, located 50 km south of the ore complex and thought to be related to Caledonian subduction, gave an age of 451 Ma, within the range of monazite ages. Textural relations together with the mineral ages favor an epigenetic rather than a syngenetic origin for the orebodies. REE mineralization started around 555 Ma (disseminated monazite in the West, the Main, and south of the East Orebody), but the main mineralization (banded ores) was related to the Caledonian subduction event ca. 474-400 Ma. ?? 1994.

  5. 238U- and 232Th-decay series constraints on the timescales of crystal fractionation to produce the phonolite erupted in 2004 near Tristan da Cunha, South Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Reagan, Mark K.; Turner, Simon; Legg, Matthew; Sims, Kenneth W. W.; Hards, Victoria L.

    2008-09-01

    Phonolite pumice found floating offshore of Tristan da Cunha following intense seismic activity southeast of the island July 29-30, 2004 was analyzed for 238U- and 232Th-series nuclides to determine initial 230Th, 226Ra, 210Pb, 210Po, 228Ra, and 228Th activities. The initial ( 210Po/ 210Pb) value of 0.15 for the phonolite shows that, like most subaerial lavas, this subaqueous tephra degassed most of its 210Po upon eruption. The ( 230Th/ 232Th) and ( 238U/ 232Th) values for the phonolite are similar to those of the trachyandesites erupted in 1961 from Tristan da Cunha. However, the relative activities of 210Pb, 226Ra, and 230Th in the phonolite contrast with those of the trachyandesites, in that 210Pb and 230Th are both strongly enriched with respect to 226Ra. In addition, the phonolite had a small deficit in 228Ra with respect to 232Th. The Ra deficits likely resulted from partitioning into feldspars and hornblende in a time frame that extended over several decades to a century. These disequilibria can be explained by crystal fractionation at a decreasing rate through time at an average of 3-5 × 10 -3 year -1. The calculated crystallization rate is about an order of magnitude faster than has been calculated for most other phonolites and trachytes, and about half that calculated for crystallization of the Makaopuhi lava lake. These data imply that the 2004 magma was not the differentiated cap of a much larger body that remained at depth. Instead, it was likely the residue of a relatively small body of more mafic magma that was injected into the crust southeast Tristan and underwent extensive and rapid crystal fractionation before it erupted.

  6. Time features of delayed neutrons and partial emissive-fission cross sections for the neutron-induced fission of {sup 232}Th nuclei in the energy range 3.2-17.9 MeV

    SciTech Connect

    Roshchenko, V. A. Piksaikin, V. M. Korolev, G. G.; Egorov, A. S.

    2010-06-15

    The energy dependence of the relative abundances of delayed neutrons and the energy dependence of the half-lives of their precursors in the neutron-induced fission of {sup 232}Th nuclei in the energy range 3.2-17.9 MeV were measured for the first time. A systematics of the time features of delayed neutrons is developed. This systematics makes it possible to estimate the half-life of delayed-neutron precursors as a function of the nucleonic composition of fissile nuclei by using a single parameter set for all nuclides. The energy dependence of the partial cross sections for emissive fission in the reaction {sup 232}Th(n, f) was analyzed on the basis of data obtained for the relative abundances of delayed neutrons and the aforementioned half-lives and on the basis of the created systematics of the time features of delayed neutrons. It was shown experimentally for the first time that the decrease in the cross section after the reaction threshold in the fission of {sup 232}Th nuclei (it has a pronounced first-chance plateau) is not an exclusion among the already studied uranium, plutonium, and curium isotopes and complies with theoretical predictions obtained for the respective nuclei with allowance for shell, superfluid, and collective effects in the nuclear-level density and with allowance for preequilibrium neutron emission

  7. Delayed Fission Gamma-ray Characteristics of Th-232 U-233 U-235 U-238 and Pu-239

    SciTech Connect

    Lane, Taylor; Parma, Edward J.

    2015-08-01

    Delayed fission gamma-rays play an important role in determining the time dependent ioniz- ing dose for experiments in the central irradiation cavity of the Annular Core Research Reactor (ACRR). Delayed gamma-rays are produced from both fission product decay and from acti- vation of materials in the core, such as cladding and support structures. Knowing both the delayed gamma-ray emission rate and the time-dependent gamma-ray energy spectrum is nec- essary in order to properly determine the dose contributions from delayed fission gamma-rays. This information is especially important when attempting to deconvolute the time-dependent neutron, prompt gamma-ray, and delayed gamma-ray contribution to the response of a diamond photo-conducting diode (PCD) or fission chamber in time frames of milliseconds to seconds following a reactor pulse. This work focused on investigating delayed gamma-ray character- istics produced from fission products from thermal, fast, and high energy fission of Th-232, U-233, U-235, U-238, and Pu-239. This work uses a modified version of CINDER2008, a transmutation code developed at Los Alamos National Laboratory, to model time and energy dependent photon characteristics due to fission. This modified code adds the capability to track photon-induced transmutations, photo-fission, and the subsequent radiation caused by fission products due to photo-fission. The data is compared against previous work done with SNL- modified CINDER2008 [ 1 ] and experimental data [ 2 , 3 ] and other published literature, includ- ing ENDF/B-VII.1 [ 4 ]. The ability to produce a high-fidelity (7,428 group) energy-dependent photon fluence at various times post-fission can improve the delayed photon characterization for radiation effects tests at research reactors, as well as other applications.

  8. Searches for T-odd correlations in the emission of prompt neutrons in the polarized-neutron-induced fission of 235U nuclei

    NASA Astrophysics Data System (ADS)

    Danilyan, G. V.; Klenke, J.; Krakhotin, V. A.; Novitsky, V. V.; Pavlov, V. S.; Shatalov, P. B.

    2010-07-01

    The results of an experiment aimed at searches for formally T-odd correlations in the angular distribution of prompt neutrons from the fission of 235U nuclei are presented. The experiment was performed in the MEPHISTO polarized cold-neutron beam from the Munich FRMII reactor. The correlation coefficient proved to be (-3.5 ± 3.4) × 10-5 for a three-vector correlation (TRI effect) and (-5.0 ± 3.4) × 10-5 for a five-vector correlation (ROT effect). This means that no significant effects were discovered within the measurement errors. A comparison with the analogous effects in the ternary fission of 235U nuclei was performed. The values of the corresponding correlations in the angular distribution of prompt fission gamma rays were refined.

  9. Uranium 238U/235U isotope ratios as indicators of reduction: Results from an in situ biostimulation experiment at Rifle, Colorado, USA

    SciTech Connect

    Bopp IV, C.J.; Lundstrom, C.C.; Johnson, T.M.; Sanford, R.A.; Long, P.E.; Williams, K.H.

    2010-02-01

    The attenuation of groundwater contamination via chemical reaction is traditionally evaluated by monitoring contaminant concentration through time. However, this method can be confounded by common transport processes (e.g. dilution, sorption). Isotopic techniques bypass the limits of concentration methods, and so may provide improved accuracy in determining the extent of reaction. We apply measurements of {sup 238}U/{sup 235}U to a U bioremediation field experiment at the Rifle Integrated Field Research Challenge Site in Rifle, Colorado (USA). An array of monitoring and injection wells was installed on a 100 m{sup 2} plot where U(VI) contamination was present in the groundwater. Acetate-amended groundwater was injected along an up-gradient gallery to encourage the growth of dissimilatory metal reducing bacteria (e.g. Geobacter species). During amendment, U concentration dropped by an order of magnitude in the experiment plot. We measured {sup 238}U/{sup 235}U in samples from one monitoring well by MC-ICP-MS using a double isotope tracer method. A significant {approx}1.00{per_thousand} decrease in {sup 238}U/{sup 235}U occurred in the groundwater as U(VI) concentration decreased. The relationship between {sup 238}U/{sup 235}U and concentration corresponds approximately to a Rayleigh distillation curve with an effective fractionation factor ({alpha}) of 1.00046. We attribute the observed U isotope fractionation to a nuclear field shift effect during enzymatic reduction of U(VI){sub (aq)} to U(IV){sub (s)}.

  10. Measurement of {sup 235}U content and flow of UF{sub 6} using delayed neutrons or gamma rays following induced fission

    SciTech Connect

    Stromswold, D.C.; Peurrung, A.J.; Reeder, P.L.; Perkins, R.W.

    1996-06-01

    Feasibility experiments conducted at Pacific Northwest National Laboratory demonstrate that either delayed neutrons or energetic gamma rays from short-lived fission products can be used to monitor the blending of UF{sub 6} gas streams. A {sup 252}Cf neutron source was used to induce {sup 235}U fission in a sample, and delayed neutrons and gamma rays were measured after the sample moved {open_quotes}down-stream.{close_quotes} The experiments used a UO{sub 2} powder that was transported down the pipe to simulate the flowing UF{sub 6} gas. Computer modeling and analytic calculation extended the test results to a flowing UF{sub 6} gas system. Neutron or gamma-ray measurements made at two downstream positions can be used to indicate both the {sup 235}U content and UF{sub 6} flow rate. Both the neutron and gamma-ray techniques have the benefits of simplicity and long-term reliability, combined with adequate sensitivity for low-intrusion monitoring of the blending process. Alternatively, measuring the neutron emission rate from (a, n) reactions in the UF{sub 6} provides an approximate measure of the {sup 235}U content without using a neutron source to induce fission.

  11. Analysis of prompt fission neutrons in 235U(nth,f) and fission fragment distributions for the thermal neutron induced fission of 234U

    NASA Astrophysics Data System (ADS)

    Al-Adili, A.; Tarrío, D.; Hambsch, F.-J.; Göök, A.; Jansson, K.; Solders, A.; Rakopoulos, V.; Gustafsson, C.; Lantz, M.; Mattera, A.; Oberstedt, S.; Prokofiev, A. V.; Vidali, M.; Österlund, M.; Pomp, S.

    2016-06-01

    This paper presents the ongoing analysis of two fission experiments. Both projects are part of the collaboration between the nuclear reactions group at Uppsala and the JRC-IRMM. The first experiment deals with the prompt fission neutron multiplicity in the thermal neutron induced fission of 235U(n,f). The second, on the fission fragment properties in the thermal fission of 234U(n,f). The prompt fission neutron multiplicity has been measured at the JRC-IRMM using two liquid scintillators in coincidence with an ionization chamber. The first experimental campaign focused on 235U(nth,f) whereas a second experimental campaign is foreseen later for the same reaction at 5.5 MeV. The goal is to investigate how the so-called sawtooth shape changes as a function of fragment mass and excitation energy. Some harsh experimental conditions were experienced due to the large radiation background. The solution to this will be discussed along with preliminary results. In addition, the analysis of thermal neutron induced fission of 234U(n,f) will be discussed. Currently analysis of data is ongoing, originally taken at the ILL reactor. The experiment is of particular interest since no measurement exist of the mass and energy distributions for this system at thermal energies. One main problem encountered during analysis was the huge background of 235U(nth,f). Despite the negligible isotopic traces in the sample, the cross section difference is enormous. Solution to this parasitic background will be highlighted.

  12. Feasibility study of 235U and 239Pu characterization in radioactive waste drums using neutron-induced fission delayed gamma rays

    NASA Astrophysics Data System (ADS)

    Nicol, T.; Pérot, B.; Carasco, C.; Brackx, E.; Mariani, A.; Passard, C.; Mauerhofer, E.; Collot, J.

    2016-10-01

    This paper reports a feasibility study of 235U and 239Pu characterization in 225 L bituminized waste drums or 200 L concrete waste drums, by detecting delayed fission gamma rays between the pulses of a deuterium-tritium neutron generator. The delayed gamma yields were first measured with bare samples of 235U and 239Pu in REGAIN, a facility dedicated to the assay of 118 L waste drums by Prompt Gamma Neutron Activation Analysis (PGNAA) at CEA Cadarache, France. Detectability in the waste drums is then assessed using the MCNPX model of MEDINA (Multi Element Detection based on Instrumental Neutron Activation), another PGNAA cell dedicated to 200 L drums at FZJ, Germany. For the bituminized waste drum, performances are severely hampered by the high gamma background due to 137Cs, which requires the use of collimator and shield to avoid electronics saturation, these elements being very penalizing for the detection of the weak delayed gamma signal. However, for lower activity concrete drums, detection limits range from 10 to 290 g of 235U or 239Pu, depending on the delayed gamma rays of interest. These detection limits have been determined by using MCNPX to calculate the delayed gamma useful signal, and by measuring the experimental gamma background in MEDINA with a 200 L concrete drum mock-up. The performances could be significantly improved by using a higher interrogating neutron emission and an optimized experimental setup, which would allow characterizing nuclear materials in a wide range of low and medium activity waste packages.

  13. 210Pb- 226Ra and 228Ra- 232Th systematics in young arc lavas: implications for magma degassing and ascent rates

    NASA Astrophysics Data System (ADS)

    Turner, Simon; Black, Stuart; Berlo, Kim

    2004-10-01

    New data show that island arc rocks have ( 210Pb/ 226Ra) o ratios which range from as low as 0.24 up to 2.88. In contrast, ( 228Ra/ 232Th) appears always within error of 1 suggesting that the large 226Ra-excesses observed in arc rocks were generated more than 30 years ago. This places a maximum estimate on melt ascent velocities of around 4000 m/year and provides further confidence that the 226Ra excesses reflect deep (source) processes rather than shallow level alteration or seawater contamination. Conversely, partial melting must have occurred more than 30 years prior to eruption. The 210Pb deficits are most readily explained by protracted magma degassing. Using published numerical models, the data suggest that degassing occurred continuously for periods up to several decades just prior to eruption but no link with eruption periodicity was found. Longer periods are required if degassing is discontinuous, less than 100% efficient or if magma is recharged or stored after degassing. The long durations suggest much of this degassing occurs at depth with implications for the formation of hydrothermal and copper-porphyry systems. A suite of lavas erupted in 1985-1986 from Sangeang Api volcano in the Sunda arc are characterised by deficits of 210Pb relative to 226Ra from which 6-8 years of continuous 222Rn degassing would be inferred from recent numerical models. These data also form a linear ( 210Pb)/Pb-( 226Ra)/Pb array which might be interpreted as a 71-year isochron. However, the array passes through the origin suggesting displacement downwards from the equiline in response to degassing and so the slope of the array is inferred not to have any age significance. Simple modelling shows that the range of ( 226Ra)/Pb ratios requires thousands of years to develop consistent with differentiation occurring in response to cooling at the base of the crust. Thus, degassing post-dated, and was not responsible for magma differentiation. The formation, migration and extraction

  14. Fission Product Data Measured at Los Alamos for Fission Spectrum and Thermal Neutrons on 239Pu, 235U, 238U

    NASA Astrophysics Data System (ADS)

    Selby, H. D.; Mac Innes, M. R.; Barr, D. W.; Keksis, A. L.; Meade, R. A.; Burns, C. J.; Chadwick, M. B.; Wallstrom, T. C.

    2010-12-01

    where the present results are about 4%-relative higher for neutrons incident on 239Pu and 235U. Additionally, our results illustrate the importance of representing the incident energy dependence of fission product yields over the fast neutron energy range for high-accuracy work, for example the 147Nd from neutron reactions on plutonium. An upgrade to the ENDF library, for ENDF/B-VII.1, based on these and other data, is described in a companion paper to this work.

  15. Trace element distribution and 235U/238U ratios in Euphrates waters and in soils and tree barks of Dhi Qar province (southern Iraq).

    PubMed

    Riccobono, Francesco; Perra, Guido; Pisani, Anastasia; Protano, Giuseppe

    2011-09-01

    To assess the quality of the environment in southern Iraq after the Gulf War II, a geochemical survey was carried out. The survey provided data on the chemistry of Euphrates waters, as well as the trace element contents, U and Pb isotopic composition, and PAH levels in soil and tree bark samples. The trace element concentrations and the (235)U/(238)U ratio values in the Euphrates waters were within the usual natural range, except for the high contents of Sr due to a widespread presence of gypsum in soils of this area. The trace element contents in soils agreed with the common geochemistry of soils from floodplain sediments. Some exceptions were the high contents of Co, Cr and Ni, which had a natural origin related to ophiolitic outcrops in the upper sector of the Euphrates basin. The high concentrations of S and Sr were linked to the abundance of gypsum in soils. A marked geochemical homogeneity of soil samples was suggested by the similar distribution pattern of rare earth elements, while the (235)U/(238)U ratio was also fairly homogeneous and within the natural range. The chemistry of the tree bark samples closely reflected that of the soils, with some notable exceptions. Unlike the soils, some tree bark samples had anomalous values of the (235)U/(238)U ratio due to mixing of depleted uranium (DU) with the natural uranium pool. Moreover, the distribution of some trace elements (such as REEs, Th and Zr) and the isotopic composition of Pb in barks clearly differed from those of the nearby soils. The overall results suggested that significant external inputs occurred implying that once formed the DU-enriched particles could travel over long distances. The polycyclic aromatic hydrocarbon concentrations in tree bark samples showed that phenanthrene, fluoranthene and pyrene were the most abundant components, indicating an important role of automotive traffic.

  16. Monte Carlo cross section testing for thermal and intermediate {sup 235}U/{sup 238}U critical assemblies, ENDF/B-V vs ENDF/B-VI

    SciTech Connect

    Weinman, J.P.

    1997-06-01

    The purpose of this study is to investigate the eigenvalue sensitivity to changes in ENDF/B-V and ENDF/B-VI cross section data sets by comparing RACER vectorized Monte Carlo calculations for several thermal and intermediate spectrum critical experiments. Nineteen Oak Ridge and Rocky Flats thermal solution benchmark critical assemblies that span a range of hydrogen-to-{sup 235}U (H/U) concentrations (2052 to 27.1) and above-thermal neutron leakage fractions (0.555 to 0.011) were analyzed. In addition, three intermediate spectrum critical assemblies (UH3-UR, UH3-NI, and HISS-HUG) were studied.

  17. Preliminary evaluation of the /sup 235/U(n,f) cross-section from 100 keV to 20 MeV

    SciTech Connect

    Bhat, M.R.

    1983-01-01

    A preliminary evaluation of the fission cross-section of /sup 235/U from 100 keV to 20 MeV is described. Variance-covariance matrices for a number of experimental data sets were constructed and used to evaluate the fission cross-section following a Bayesian procedure. The evaluated fission cross-section is compared with experimental data including the /sup 252/Cf fission neutron spectrum averages and some of the problems encountered in carrying out the fit are discussed.

  18. Preliminary Report on the Population of the 235U T1/2=25-Minute Isomer by the (Nu,Nu'Gamma)Reaction

    SciTech Connect

    Younes, W; Britt, H C; Becker, J A; Bernstein, L A; Garrett, P E; McGrath, C A; McNabb, D P; Nelson, R O; Devlin, M; Fotiades, N

    2002-10-09

    The population cross section of the T{sub 1/2} = 25-minute, E{sub x} = 76.8-keV isomer in {sup 235}U via the {sup 235}U(n,n{prime}{gamma}) reaction has been estimated in the E{sub n} = 2.1-20-MeV range. Gamma rays populating both isomer and ground states were detected using the GEANIE spectrometer at the LANSCE/WNR ''white-source'' neutron facility. Partial {gamma}-ray cross sections were obtained as a function of incident neutron energy, using {gamma}-ray spectroscopy and the time-of-flight technique. A correction for unobserved transitions was applied to the measured partial cross sections using the Hauser-Feshbach code GNASH to produce population cross sections for the isomer- and ground-state levels. The deduced isomer population cross section at E{sub n} = 2.1 MeV is 1.1(1) b, and the isomer-to-ground state population ratio decreases from 0.9 to 0.06 over the E{sub n} = 2.1-20-MeV range. The details of the measurement and recommendations to improve the current results are discussed.

  19. True ternary fission, the collinear decay into fragments of similar size in the 252Cf(sf) and 235U(nth, f) reactions

    NASA Astrophysics Data System (ADS)

    von Oertzen, W.; Nasirov, A. K.

    2014-06-01

    The collinear cluster decay in 252Cf(sf, fff), with three cluster fragments of different masses (e.g. 132Sn, 52-48Ca, 68-72Ni), which has been observed by the FOBOS group in JINR, has established a new decay mode of heavy nuclei, the collinear cluster tripartition (CCT). The same type of ternary fission decay has been observed in the reaction 235U(nth, fff). This kind of “true ternary fission” of heavy nuclei has been predicted many times in theoretical works during the last decades. In the present note we discuss true ternary fission (TFFF) into three nuclei of almost equal size (e.g. Z=98→Zi=32, 34, 32) in the same systems. The possible fission channels are predicted from potential-energy (PES) calculations. These PES's show pronounced minima for several ternary fragmentation decays, e.g. for 252Cf(sf) and for 235U(nth, f). They suggest the existence of a variety of collinear ternary fission modes. The TFFF-decays chosen in this letter have very similar dynamical features as the previously observed collinear CCT-decays. The data obtained in the above mentioned experiments allow us to extract the yield for these TFFF-decays in both systems by using specific gates on the measured parameters. These yields are a few 1.0ṡ10-6/(binary fission).

  20. Effects of Neutron Emission on Fragment Mass and Kinetic Energy Distribution from Thermal Neutron-Induced Fission of {sup 235}U

    SciTech Connect

    Montoya, M.; Rojas, J.; Saetone, E.

    2007-10-26

    The mass and kinetic energy distribution of nuclear fragments from thermal neutron-induced fission of {sup 235}U(n{sub th},f) have been studied using a Monte-Carlo simulation. Besides reproducing the pronounced broadening in the standard deviation of the kinetic energy at the final fragment mass number around m = 109, our simulation also produces a second broadening around m = 125. These results are in good agreement with the experimental data obtained by Belhafaf et al. and other results on yield of mass. We conclude that the obtained results are a consequence of the characteristics of the neutron emission, the sharp variation in the primary fragment kinetic energy and mass yield curves. We show that because neutron emission is hazardous to make any conclusion on primary quantities distribution of fragments from experimental results on final quantities distributions.

  1. Determination of 234U/238U, 235U/238U and 236U/238U isotope ratios in urine using sector field inductively coupled plasma mass spectrometry.

    PubMed

    Xiao, Ge; Jones, Robert L; Saunders, David; Caldwell, Kathleen L

    2014-12-01

    Quantification of the isotopic composition of uranium in urine at low levels of concentration is important for assessing both military and civilian populations' exposures to uranium. However, until now there has been no convenient, precise method established for rapid determination of multiple uranium isotope ratios. Here, the authors report a new method to measure (234)U/(238)U, (235)U/(238)U and (236)U/(238)U. It uses solid-phase chelation extraction (via TRU columns) of actinides from the urine matrix, followed by measurement using a magnetic sector field inductively coupled plasma mass spectrometer (SF-ICP-MS-Thermo Element XR) equipped with a high-efficiency nebulizer (Apex PFA microflow) and coupled with a membrane desolvating nebulizer system (Aridus II™). This method provides rapid and reliable results and has been used successfully to analyse Certified Reference Materials. PMID:24563523

  2. Critical experiments with 4. 31 wt % /sup 235/U-enriched UO/sub 2/ rods in highly borated water lattices

    SciTech Connect

    Durst, B.M.; Bierman, S.R.; Clayton, E.D.

    1982-08-01

    A series of critical experiments were performed with 4.31 wt % /sup 235/U enriched UO/sub 2/ fuel rods immersed in water containing various concentrations of boron ranging up to 2.55 g/l. The boron was added in the form of boric acid (H/sub 3/BO/sub 3/). Critical experimental data were obtained for two different lattice pitches wherein the water-to-uranium oxide volume ratios were 1.59 and 1.09. The experiments provide benchmarks on heavily borated systems for use in validating calculational techniques employed in analyzing fuel shipping casks and spent fuel storage systems that may utilize boron for criticality control.

  3. Fission-fragment angular distributions and total kinetic energies for /sup 235/U(n,f) from. 18 to 8. 83 MeV

    SciTech Connect

    Meadows, J.W.; Budtz-Joergensen, C.

    1982-01-01

    A gridded ion chamber was used to measure the fission fragment angular distribution and total kinetic energy for the /sup 235/U(n,f) reaction from 0.18 to 8.81 MeV neutron energy. The anisotropies are in generally good agreement with earlier measurements. The average total kinetic energy is approx. 0.2 MeV greater than the thermal value at neutron energies < 2 MeV and shows a sudden decrease of approx. 0.8 MeV between 4 and 5 MeV neutron energy, well below the (n, n'f) threshold. Possible causes of this decrease are a change in the mass distribution or decreased shell effects in the heavy fragment.

  4. Exploratory study of fission product yields of neutron-induced fission of 235U , 238U , and 239Pu at 8.9 MeV

    NASA Astrophysics Data System (ADS)

    Bhatia, C.; Fallin, B. F.; Gooden, M. E.; Howell, C. R.; Kelley, J. H.; Tornow, W.; Arnold, C. W.; Bond, E.; Bredeweg, T. A.; Fowler, M. M.; Moody, W.; Rundberg, R. S.; Rusev, G. Y.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Macri, R.; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P.

    2015-06-01

    Using dual-fission chambers each loaded with a thick (200 -400 -mg /c m2) actinide target of 235 ,238U or 239Pu and two thin (˜10 -100 -μ g /c m2) reference foils of the same actinide, the cumulative yields of fission products ranging from 92Sr to 147Nd have been measured at En= 8.9 MeV . The 2H(d ,n ) 3He reaction provided the quasimonoenergetic neutron beam. The experimental setup and methods used to determine the fission product yield (FPY) are described, and results for typically eight high-yield fission products are presented. Our FPYs for 235U(n ,f ) , 238U(n ,f ) , and 239Pu(n ,f ) at 8.9 MeV are compared with the existing data below 8 MeV from Glendenin et al. [Phys. Rev. C 24, 2600 (1981), 10.1103/PhysRevC.24.2600], Nagy et al. [Phys. Rev. C 17, 163 (1978), 10.1103/PhysRevC.17.163], Gindler et al. [Phys. Rev. C 27, 2058 (1983), 10.1103/PhysRevC.27.2058], and those of Mac Innes et al. [Nucl. Data Sheets 112, 3135 (2011), 10.1016/j.nds.2011.11.009] and Laurec et al. [Nucl. Data Sheets 111, 2965 (2010), 10.1016/j.nds.2010.11.004] at 14.5 and 14.7 MeV, respectively. This comparison indicates a negative slope for the energy dependence of most fission product yields obtained from 235U and 239Pu , whereas for 238U the slope issue remains unsettled.

  5. Ground water contamination with (238)U, (234)U, (235)U, (226)Ra and (210)Pb from past uranium mining: cove wash, Arizona.

    PubMed

    Dias da Cunha, Kenya Moore; Henderson, Helenes; Thomson, Bruce M; Hecht, Adam A

    2014-06-01

    The objectives of the study are to present a critical review of the (238)U, (234)U, (235)U, (226)Ra and (210)Pb levels in water samples from the EPA studies (U.S. EPA in Abandoned uranium mines and the Navajo Nation: Red Valley chapter screening assessment report. Region 9 Superfund Program, San Francisco, 2004, Abandoned uranium mines and the Navajo Nation: Northern aum region screening assessment report. Region 9 Superfund Program, San Francisco, 2006, Health and environmental impacts of uranium contamination, 5-year plan. Region 9 Superfund Program, San Franciso, 2008) and the dose assessment for the population due to ingestion of water containing (238)U and (234)U. The water quality data were taken from Sect. "Data analysis" of the published report, titled Abandoned Uranium Mines Project Arizona, New Mexico, Utah-Navajo Lands 1994-2000, Project Atlas. Total uranium concentration was above the maximum concentration level for drinking water (7.410-1 Bq/L) in 19 % of the water samples, while (238)U and (234)U concentrations were above in 14 and 17 % of the water samples, respectively. (226)Ra and (210)Pb concentrations in water samples were in the range of 3.7 × 10(-1) to 5.55 × 102 Bq/L and 1.11 to 4.33 × 102 Bq/L, respectively. For only two samples, the (226)Ra concentrations exceeded the MCL for total Ra for drinking water (0.185 Bq/L). However, the (210)Pb/(226)Ra ratios varied from 0.11 to 47.00, and ratios above 1.00 were observed in 71 % of the samples. Secular equilibrium of the natural uranium series was not observed in the data record for most of the water samples. Moreover, the (235)U/(total)U mass ratios ranged from 0.06 to 5.9 %, and the natural mass ratio of (235)U to (total)U (0.72 %) was observed in only 16 % of the water samples, ratios above or below the natural ratio could not be explained based on data reported by U.S. EPA. In addition, statistical evaluations showed no correlations among the distribution of the radionuclide concentrations

  6. Intracellular potassium: 40K as a primordial gene irradiator.

    PubMed Central

    Moore, F D; Sastry, K S

    1982-01-01

    We have been interested in the possibility that the low energy electrons (Auger and Coster-Kronig) emitted after the electron capture decay of 40K may have highly localized radiochemical effects on the genetic material--effects dependent upon the intracellular locus of potassium. We report here that these effects are such that the likelihood of mutagenesis by their impact on DNA is substantial. This suggests that intracellular 40K has played a significant role as a mutagenic agent in evolution. PMID:6954503

  7. Trace metal cycling and 238U/235U in New Zealand's fjords: Implications for reconstructing global paleoredox conditions in organic-rich sediments

    NASA Astrophysics Data System (ADS)

    Hinojosa, Jessica L.; Stirling, Claudine H.; Reid, Malcolm R.; Moy, Christopher M.; Wilson, Gary S.

    2016-04-01

    Reconstructing the history of ocean oxygenation provides insight into links between ocean anoxia, biogeochemical cycles, and climate. Certain redox-sensitive elements respond to changes in marine oxygen content through phase shifts and concomitant isotopic fractionation, providing new diagnostic proxies of past ocean hypoxia. Here we explore the behavior and inter-dependence of a suite of commonly utilized redox-sensitive trace metals (U, Mo, Fe, and Mn) and the emerging "stable" isotope system of U (238U/235U, or δ238U) in New Zealand fjords. These semi-restricted basins have chemical conditions spanning the complete redox spectrum from fully oxygenated to suboxic to intermittently anoxic/euxinic. In the anoxic water column, U and Mo concentrations decrease, while Fe and Mn concentrations increase. Similarly, signals of past euxinic conditions can be found by U, Mo, Fe, and Mn enrichment in the underlying sediments. The expected U isotopic shift toward a lower δ238U in the anoxic water column due to U(VI)-U(IV) reduction is not observed; instead, water column δ238U profiles are consistent in fjords of all oxygen content, falling within previously reported ranges for open ocean seawater (δ238U = -0.42 ± 0.07‰). Additionally, surface sediment δ238U results show evidence for competing U isotope fractionation processes. One site indicates increased export of 238U from seawater to the underlying sediments (fractionation between aqueous seawater U and particulate sediment U, or ΔU(aq)-U(solid) = -0.25‰), consistent with redox-driven fractionation. Another site suggests potential U(VI) adsorption-driven fractionation, reflecting increased export of 235U from seawater to sediments (ΔU(aq)-U(solid) = 0.25‰). We discuss several potential factors that could alter δ238U in waters and sediments beyond redox-driven shifts, including adsorption to organic matter in waters of high primary productivity, reaction rates for competing processes of U adsorption and

  8. X-34 40K Fastrac II Engine Test

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This is a photo of an X-34 40K Fastrac II duration test performed at the Marshall Space Flight Center test stand 116 (TS116) in June 1997. Engine ignition is started with Tea-Gas which makes the start burn green. The X-34 program was cancelled in 2001.

  9. Certified reference materials for radionuclides in Bikini Atoll sediment (IAEA-410) and Pacific Ocean sediment (IAEA-412).

    PubMed

    Pham, M K; van Beek, P; Carvalho, F P; Chamizo, E; Degering, D; Engeler, C; Gascó, C; Gurriaran, R; Hanley, O; Harms, A V; Herrmann, J; Hult, M; Ikeuchi, Y; Ilchmann, C; Kanisch, G; Kis-Benedek, G; Kloster, M; Laubenstein, M; Llaurado, M; Mas, J L; Nakano, M; Nielsen, S P; Osvath, I; Povinec, P P; Rieth, U; Schikowski, J; Smedley, P A; Suplinska, M; Sýkora, I; Tarjan, S; Varga, B; Vasileva, E; Zalewska, T; Zhou, W

    2016-03-01

    The preparation and characterization of certified reference materials (CRMs) for radionuclide content in sediments collected offshore of Bikini Atoll (IAEA-410) and in the open northwest Pacific Ocean (IAEA-412) are described and the results of the certification process are presented. The certified radionuclides include: (40)K, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (234)U, (238)U, (239)Pu, (239+240)Pu and (241)Am for IAEA-410 and (40)K, (137)Cs, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (235)U, (238)U, (239)Pu, (240)Pu and (239+240)Pu for IAEA-412. The CRMs can be used for quality assurance and quality control purposes in the analysis of radionuclides in sediments, for development and validation of analytical methods and for staff training.

  10. Certified reference materials for radionuclides in Bikini Atoll sediment (IAEA-410) and Pacific Ocean sediment (IAEA-412).

    PubMed

    Pham, M K; van Beek, P; Carvalho, F P; Chamizo, E; Degering, D; Engeler, C; Gascó, C; Gurriaran, R; Hanley, O; Harms, A V; Herrmann, J; Hult, M; Ikeuchi, Y; Ilchmann, C; Kanisch, G; Kis-Benedek, G; Kloster, M; Laubenstein, M; Llaurado, M; Mas, J L; Nakano, M; Nielsen, S P; Osvath, I; Povinec, P P; Rieth, U; Schikowski, J; Smedley, P A; Suplinska, M; Sýkora, I; Tarjan, S; Varga, B; Vasileva, E; Zalewska, T; Zhou, W

    2016-03-01

    The preparation and characterization of certified reference materials (CRMs) for radionuclide content in sediments collected offshore of Bikini Atoll (IAEA-410) and in the open northwest Pacific Ocean (IAEA-412) are described and the results of the certification process are presented. The certified radionuclides include: (40)K, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (234)U, (238)U, (239)Pu, (239+240)Pu and (241)Am for IAEA-410 and (40)K, (137)Cs, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (235)U, (238)U, (239)Pu, (240)Pu and (239+240)Pu for IAEA-412. The CRMs can be used for quality assurance and quality control purposes in the analysis of radionuclides in sediments, for development and validation of analytical methods and for staff training. PMID:26631455

  11. Determination of Fission Product Yields of 235U, 238U and 239Pu for Neutron Energies from 0.5 to 14.8 MeV

    NASA Astrophysics Data System (ADS)

    Gooden, Matthew; Arnold, Charles; Becker, John; Bhatia, Chitra; Bhike, Megha; Fallin, Brent; Fowler, Malcolm; Howell, Calvin; Kelley, John; Stoyer, Mark; Tonchev, Anton; Tornow, Werner; Viera, David; Wilhelmy, Jerry

    2013-10-01

    A joint TUNL-LANL-LLNL collaboration has been formed to study the issue of possible energy dependences for fission product isotopes. Work has been carried out at the TUNL 10 MV Tandem accelerator which produces nearly mono-energetic neutrons via either 2H(d,n)3He,3H(d,n)4He, or 3H(p,n)3He reactions. Three dual fission ionization chambers dedicated to 235U, 238U and 239Pu thick target foils and thin monitor foils respectively, were exposed to the neutron beams. After irradiation, thick target foils were gamma counted over a period of 1-2 months and characteristic gamma rays from fission products were recorded using HPGe detectors at TUNL's low background counting area. Using the dual fission chambers fission product yields relative to total number of fissions were determined at a high precision of 2-3% as well as absolute fission product yields at a lower precision of 5-6%. Results will be presented for a number of fission product isotopes at 1.38, 4.6 and 14.8 MeV as well as preliminary results at 9 MeV.

  12. Energy Dependence of Neutron-Induced Fission Product Yields of 235U, 238U and 239Pu Between 0.5 and 14.8 MeV

    NASA Astrophysics Data System (ADS)

    Gooden, Matthew; Tornow, Werner; Tonchev, Anton; Vieira, Dave; Wilhelmy, Jerry; Arnold, Charles; Fowler, Malcolm; Stoyer, Mark

    2014-09-01

    Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements have been performed. The energy dependence of a number of cumulative fission products between 0.5 and 14.8 MeV have been measured using quasi-monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of activation utilizing specially designed dual-fission chambers and γ-ray counting. The dual-fission chambers are back-to-back ionization chambers encasing a target with thin deposits of the same target isotope in each chamber. This method allows for the direct measurement of the fission rate in the activation target with no reference to the fission cross-section, reducing uncertainties. γ-ray counting was performed on well-shield HPGe detectors over a period of 2 months per activation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 4.6 and 14.8 MeV.

  13. Determination of Fission Product Yields of 235U, 238U and 239Pu for Neutron Energies from 0.5 to 14.8 MeV

    NASA Astrophysics Data System (ADS)

    Gooden, Matthew; Arnold, Charles; Becker, John; Bhatia, Chitra; Bhike, Megha; Fowler, Malcolm; Howell, Calvin; Kelley, John; Stoyer, Mark; Tonchev, Anton; Tornow, Werner; Vieira, Dave; Wilhelmy, Jerry

    2014-03-01

    A joint TUNL-LANL-LLNL collaboration has been formed to study the issue of possible energy dependences for certain fission product isotopes. Work has been carried out at the TUNL 10 MV Tandem accelerator which produces nearly mono-energetic neutrons via either 2H(d,n)3He,3H(d,n)4He,or3H(p,n)3He reactions. Three dual fission ionization chambers dedicated to 235U, 238U and 239Pu thick target foils and thin monitor foils respectively, were exposed to the neutron beams. After irradiation, thick target foils were gamma counted over a period of 1-2 months and characteristic gamma rays from fission products were recorded using HPGe detectors at TUNL's low background counting area. Using the dual fission chambers, relative fission product yield were determined at a high precision of 2-3 % as well as absolute fission product yields at a lower precision of 5-6 %. Preliminary results will be presented for a number of fission product isotopes over the incident neutron energy range of 0.5 to 14.8 MeV.

  14. Effects of Fission Yield Data in the Calculation of Antineutrino Spectra for ^{235}U(n,fission) at Thermal and Fast Neutron Energies.

    PubMed

    Sonzogni, A A; McCutchan, E A; Johnson, T D; Dimitriou, P

    2016-04-01

    Fission yields form an integral part of the prediction of antineutrino spectra generated by nuclear reactors, but little attention has been paid to the quality and reliability of the data used in current calculations. Following a critical review of the thermal and fast ENDF/B-VII.1 ^{235}U fission yields, deficiencies are identified and improved yields are obtained, based on corrections of erroneous yields, consistency between decay and fission yield data, and updated isomeric ratios. These corrected yields are used to calculate antineutrino spectra using the summation method. An anomalous value for the thermal fission yield of ^{86}Ge generates an excess of antineutrinos at 5-7 MeV, a feature which is no longer present when the corrected yields are used. Thermal spectra calculated with two distinct fission yield libraries (corrected ENDF/B and JEFF) differ by up to 6% in the 0-7 MeV energy window, allowing for a basic estimate of the uncertainty involved in the fission yield component of summation calculations. Finally, the fast neutron antineutrino spectrum is calculated, which at the moment can only be obtained with the summation method and may be relevant for short baseline reactor experiments using highly enriched uranium fuel. PMID:27081973

  15. Uranium ((234)U, (235)U and (238)U) contamination of the environment surrounding phosphogypsum waste heap in Wiślinka (northern Poland).

    PubMed

    Olszewski, Grzegorz; Boryło, Alicja; Skwarzec, Bogdan

    2015-08-01

    The aim of this work was to determine the uranium concentration ((234)U, (235)U and (238)U) and values of the activity ratio (234)U/(238)U in soil samples collected near phosphogypsum waste heap in Wiślinka (northern Poland). On the basis of the studies it was found that the values of the (234)U/(238)U activity ratio in the analyzed soils collected in the vicinity of phosphogypsum dump in Wiślinka are in most cases close to one and indicate the phosphogypsum origin of the analyzed nuclides. The obtained results of uranium concentrations are however much lower than in previous years before closing of the phosphogypsum stockpile. After this process and covering the phosphogypsum stockpile in Wiślinka with sewage sludge, phosphogypsum particles are successfully immobilized. In the light of the results the use of phosphate fertilizers seems to be a major problem. Prolonged and heavy rains can cause leaching accumulated uranium isotopes in the phosphogypsum stockpile, which will be washed into the Martwa Wisła and on the fields in the immediate vicinity of this storage.

  16. Uranium ((234)U, (235)U and (238)U) contamination of the environment surrounding phosphogypsum waste heap in Wiślinka (northern Poland).

    PubMed

    Olszewski, Grzegorz; Boryło, Alicja; Skwarzec, Bogdan

    2015-08-01

    The aim of this work was to determine the uranium concentration ((234)U, (235)U and (238)U) and values of the activity ratio (234)U/(238)U in soil samples collected near phosphogypsum waste heap in Wiślinka (northern Poland). On the basis of the studies it was found that the values of the (234)U/(238)U activity ratio in the analyzed soils collected in the vicinity of phosphogypsum dump in Wiślinka are in most cases close to one and indicate the phosphogypsum origin of the analyzed nuclides. The obtained results of uranium concentrations are however much lower than in previous years before closing of the phosphogypsum stockpile. After this process and covering the phosphogypsum stockpile in Wiślinka with sewage sludge, phosphogypsum particles are successfully immobilized. In the light of the results the use of phosphate fertilizers seems to be a major problem. Prolonged and heavy rains can cause leaching accumulated uranium isotopes in the phosphogypsum stockpile, which will be washed into the Martwa Wisła and on the fields in the immediate vicinity of this storage. PMID:25913057

  17. Effects of Fission Yield Data in the Calculation of Antineutrino Spectra for 235U (n ,fission) at Thermal and Fast Neutron Energies

    NASA Astrophysics Data System (ADS)

    Sonzogni, A. A.; McCutchan, E. A.; Johnson, T. D.; Dimitriou, P.

    2016-04-01

    Fission yields form an integral part of the prediction of antineutrino spectra generated by nuclear reactors, but little attention has been paid to the quality and reliability of the data used in current calculations. Following a critical review of the thermal and fast ENDF/B-VII.1 235U 235 fission yields, deficiencies are identified and improved yields are obtained, based on corrections of erroneous yields, consistency between decay and fission yield data, and updated isomeric ratios. These corrected yields are used to calculate antineutrino spectra using the summation method. An anomalous value for the thermal fission yield of 86Ge generates an excess of antineutrinos at 5-7 MeV, a feature which is no longer present when the corrected yields are used. Thermal spectra calculated with two distinct fission yield libraries (corrected ENDF/B and JEFF) differ by up to 6% in the 0-7 MeV energy window, allowing for a basic estimate of the uncertainty involved in the fission yield component of summation calculations. Finally, the fast neutron antineutrino spectrum is calculated, which at the moment can only be obtained with the summation method and may be relevant for short baseline reactor experiments using highly enriched uranium fuel.

  18. Effects of Fission Yield Data in the Calculation of Antineutrino Spectra for ^{235}U(n,fission) at Thermal and Fast Neutron Energies.

    PubMed

    Sonzogni, A A; McCutchan, E A; Johnson, T D; Dimitriou, P

    2016-04-01

    Fission yields form an integral part of the prediction of antineutrino spectra generated by nuclear reactors, but little attention has been paid to the quality and reliability of the data used in current calculations. Following a critical review of the thermal and fast ENDF/B-VII.1 ^{235}U fission yields, deficiencies are identified and improved yields are obtained, based on corrections of erroneous yields, consistency between decay and fission yield data, and updated isomeric ratios. These corrected yields are used to calculate antineutrino spectra using the summation method. An anomalous value for the thermal fission yield of ^{86}Ge generates an excess of antineutrinos at 5-7 MeV, a feature which is no longer present when the corrected yields are used. Thermal spectra calculated with two distinct fission yield libraries (corrected ENDF/B and JEFF) differ by up to 6% in the 0-7 MeV energy window, allowing for a basic estimate of the uncertainty involved in the fission yield component of summation calculations. Finally, the fast neutron antineutrino spectrum is calculated, which at the moment can only be obtained with the summation method and may be relevant for short baseline reactor experiments using highly enriched uranium fuel.

  19. Coulomb and even-odd effects in cold and super-asymmetric fragmentation for thermal neutron induced fission of 235U

    NASA Astrophysics Data System (ADS)

    Montoya, M.

    2016-07-01

    Even-odd effects of the maximal total kinetic energy (Kmax) as a function of charge (Z) and mass (A) of fragments from thermal neutron induced fission of actinides are questioned by other authors. In this work, visiting old results on thermal neutron induced fission of 235U, those even-odd effects are reconfirmed. The cases seeming to contradict even-odd effects are interpreted with the Coulomb effect hypothesis. According to Coulomb effect hypothesis, Kmax is equal to the Coulomb interaction energy of the most compact scission configuration. As a consequence, between two isobaric charge splits with similar Q-values, the more asymmetrical one will get the more compact scission configuration and then it will reach the higher Kmax-value. In some cases, the more asymmetrical charge split corresponds, by coincidence, to an odd charge split; consequently its higher Kmax-value may be misinterpreted as anti-even-odd effect. Another experimental result reported in the literature is the increasing of even-odd effects on charge distribution on the more asymmetrical fragmentations region. In this region, the difference between Kmax and Q-values increases with asymmetry, which means that the corresponding scission configuration needs higher total deformation energy to occur. Higher deformation energy of the fragments implies lower free energy to break nucleon pairs. Consequently, in the asymmetric fragmentation region, the even-odd effects of the distribution of proton number and neutron number must increase with asymmetry.

  20. Diffusion in the Muscovite 40K Decay System (Invited)

    NASA Astrophysics Data System (ADS)

    Harrison, T. M.

    2010-12-01

    The considerable potential of muscovite for thermochronological applications is beginning to be fully exploited following the belated publication of Ar kinetic data. Muscovite’s high potassium content, low solubility for excess 40Ar*, and ubiquitous presence in regionally metamorphosed terranes make it an important phase for 40Ar/39Ar thermochronometry, particularly in light of recognition that both age spectra and vacuum-step-heating-derived 39Ar Arrhenius plots reflect Ar release via the same volume diffusion mechanism. Thus instead of assuming a nominal closure temperature to estimate a single T-t datum, continuous and accurate thermal histories can be inferred in a similar fashion to that well-documented for K-feldspar using the multi-diffusion domain (MDD) model. The Arrhenius parameters for Ar diffusion in muscovite (E=64 kcal/mol, Do=4 cm2/s) correspond to an effective intragrain closure temperature range of ~500 to 300oC for ca. 100 μm grains cooling at ~10oC/Ma at 5 kbar. However, even greater exploitation of the 40K decay system remains possible as only one of every ten 40K atoms decay to 40Ar. The other 90% decay to 40Ca giving the 40K-40Ca branch, in principle, greater sensitivity for dating high K/Ca minerals such as muscovite. The advent of the ‘double-plus’ SIMS 40K++-40Ca++ dating method, which permits analysis of Ca isotopes at an MRP of ~4k rather than the ~25k required for full separation of 40K+ from 40Ca+, opens up the prospect of directly revealing 40K-40Ca closure profiles in muscovite (as opposed to their indirect inference from inversion of 40Ar/39Ar data through the MDD model) at a gain of enhanced precision and accuracy in thermal history reconstruction. We have used SIMS to observe K-Ca age variations in natural muscovites pressed into In. Translating this data into thermal history information, however, requires knowledge of the Arrhenius parameters for Ca tracer diffusion in muscovite. We are undertaking hydrothermal piston

  1. Thallium, uranium, and {sup 235}U/{sup 238}U ratios in the digestive gland of American lobster (Homarus americanus) from an industrialized harbor

    SciTech Connect

    Chou, C.L.; Uthe, J.F.

    1995-01-01

    Only a few studies have concentrated on elements such as thallium (TI). Uranium (U) has been studied as a radionuclide of concern in food and the environment. Foodstuffs contain 10-100 ng U{center_dot}{sup -1} with vegetables and cereals contributing most heavily to the daily intake of ca 1.5 ug U. Between 10-30% of ingested U is absorbed, with most being stored in bone. Rainbow trout (onchorynchus mykiss) and longnose sucker (Catostomus catostomus) from a lake with naturally high radioactivity contained < 5 ng U{center_dot}g{sup -1} in the flesh. Trout bone contained 40 ng U{center_dot}g{sup -1}. Higher tissue U concentrations occurred in fish from areas receiving U mining wastes. Bioconcentration factors for bone and flesh were estimated to be low, 118 and 14.7, respectively. This paper describes the Inductively coupled plasma-mass spectrometry (ICP-MS) determination of Tl and U in digestive gland tissue from lobsters captured in the vicinity of Belledune Harbor, New Brunswick, Canada. The harbor is the site of a lead smelter, a fertilizer plant, and a coal-fired power station (the latter due to enter production in late 1993) and thus has the potential of adding significant amounts of Tl to the local marine environment. The accumulation of Tl from water by marine shellfish is low, at least for bivalves, and the accumulated Tl is eliminated in a number of days when the animals are transferred to clean water. Bioconcentration factors for U in finfish ranged from 0.4-17 for larger species. However, because of the high concentrations of various trace elements in lobster digestive gland, its desirability as a foodstuff, and its relatively large size (approximately 20% of the edible tissue yield), we have investigated Tl and U concentrations and {sup 235U}/{sup 238U} ratios in it. 15 refs., 1 fig., 3 tabs.

  2. Procedures for the use of Lexan and Makrofol SSNTDs in the detection of environmental concentrations of {sup 235}U and {sup 239}Pu

    SciTech Connect

    Henderson, C.L.

    1993-03-01

    Solid State Nuclear Track Detectors are used to study a variety of atomic particles. Polycarbonate SSNTD is used to study environmental concentrations of {sup 235}U and {sup 239}Pu in human urine and feces through fission track analysis. The samples of interest are deposited upon a Lexan slide, covered with a piece of Makrofol and exposed to a neutron fluence of 1.1 X 10{sup 17}. The fissile isotopes in the sample fission and the resulting fission fragments pass through either the surface of the Lexan or the surface of the Makrofol. The positive Coulombic attraction of the ionized fission fragments causes the electrons of the polycarbonate lattice to move towards the path of these particles, resulting in the breakage of chemical bonds in the lattice. The detector is then chemically etched in 6.5 N KOH that preferentially dissolves the damaged polycarbonate left in the path of the fission fragment. The chemically etched fission tracks are permanent records of the path of the fission fragment. The etched fission tracks in Lexan are optically counted using a microscope and the fission tracks in Makrofol are counted using a Spark Chamber. The amount of fissile material in the original sample can be calculated from the number of fission tracks. This paper presents further details of procedures for etching fission tracks in Lexan and Makrofol and for operating a Spark Chamber to count etched fission tracks in Makrofol. The physics of fission track formation in dielectric detectors is also discussed, as well as the physics of the Spark Chamber.

  3. Commercial Modular Aero-Propulsion System Simulation 40k

    NASA Technical Reports Server (NTRS)

    Guo, Ten-Huei; Lavelle, Thomas; Litt, Jonathan; Csank, Jeffrey; May, Ryan

    2011-01-01

    The Commercial Modular Aero-Propulsion System Simulation 40k (CMAPSS40k) software package is a nonlinear dynamic simulation of a 40,000-pound (approximately equals 178-kN) thrust class commercial turbofan engine, written in the MATLAB/Simulink environment. The model has been tuned to capture the behavior of flight test data, and is capable of running at any point in the flight envelope [up to 40,000 ft (approximately equals 12,200 m) and Mach 0.8]. In addition to the open-loop engine, the simulation includes a controller whose architecture is representative of that found in industry. C-MAPSS40k fills the need for an easy-to-use, realistic, transient simulation of a medium-size commercial turbofan engine with a representative controller. It is a detailed component level model (CLM) written in the industry-standard graphical MATLAB/Simulink environment to allow for easy modification and portability. At the time of this reporting, no other such model exists in the public domain.

  4. In situ 40K-40Ca ‘double-plus’ SIMS dating resolves Klokken feldspar 40K-40Ar paradox

    NASA Astrophysics Data System (ADS)

    Harrison, T. Mark; Heizler, Matthew T.; McKeegan, Kevin D.; Schmitt, Axel K.

    2010-11-01

    The 40K- 40Ca decay system has not been widely utilized as a geochronometer because quantification of radiogenic daughter is difficult except in old, extremely high K/Ca domains. Even these environments have not heretofore been exploited by ion microprobe analysis due to the very high mass resolving power (MRP) of 25,000 required to separate 40K + from 40Ca +. We introduce a method that utilizes doubly-charged K and Ca species which permits isotopic measurements to be made at relatively low MRP (~ 5000). We used this K-Ca 'double-plus' approach to address an enduring controversy in 40Ar/ 39Ar thermochronology revolving around exsolved alkali feldspars from the 1166 Ma Klokken syenite (southern Greenland). Ion microprobe 40K- 40Ca analysis of Klokken samples reveal both isochron and pseudoisochron behaviors that reflect episodic isotopic and chemical exchange of coarsely exsolved perthites and a near end-member K-feldspar until ≤ 719 Ma, and perhaps as late at ~ 400 Ma. Feldspar microtextures in the Klokken syenite evolved over a protracted interval by non-thermal processes (fluid-assisted recrystallization) and thus this sample makes a poor model from which to address the general validity of 40Ar/ 39Ar thermochronological methodologies.

  5. Study on Prompt Fission Neutron Spectra and Associated Covariances for 235U(nth,f) and 239Pu(nth,f)

    NASA Astrophysics Data System (ADS)

    Berge, L.; Litaize, O.; Serot, O.; Jean, C. De Saint; Archier, P.; Peneliau, Y.

    normalization of experimental spectra, and the uncertainty on the energy-dependent neutron detection efficiency. We show the resulting PFNS and associated covariance matrix in the case of thermal neutron-induced fission of 235U and 239Pu.

  6. ZPR-3 Assembly 6F : A spherical assembly of highly enriched uranium, depleted uranium, aluminum and steel with an average {sup 235}U enrichment of 47 atom %.

    SciTech Connect

    Lell, R. M.; McKnight, R. D; Schaefer, R. W.; Nuclear Engineering Division

    2010-09-30

    Over a period of 30 years, more than a hundred Zero Power Reactor (ZPR) critical assemblies were constructed at Argonne National Laboratory. The ZPR facilities, ZPR-3, ZPR-6, ZPR-9 and ZPPR, were all fast critical assembly facilities. The ZPR critical assemblies were constructed to support fast reactor development, but data from some of these assemblies are also well suited for nuclear data validation and to form the basis for criticality safety benchmarks. A number of the Argonne ZPR/ZPPR critical assemblies have been evaluated as ICSBEP and IRPhEP benchmarks. Of the three classes of ZPR assemblies, engineering mockups, engineering benchmarks and physics benchmarks, the last group tends to be most useful for criticality safety. Because physics benchmarks were designed to test fast reactor physics data and methods, they were as simple as possible in geometry and composition. The principal fissile species was {sup 235}U or {sup 239}Pu. Fuel enrichments ranged from 9% to 95%. Often there were only one or two main core diluent materials, such as aluminum, graphite, iron, sodium or stainless steel. The cores were reflected (and insulated from room return effects) by one or two layers of materials such as depleted uranium, lead or stainless steel. Despite their more complex nature, a small number of assemblies from the other two classes would make useful criticality safety benchmarks because they have features related to criticality safety issues, such as reflection by soil-like material. ZPR-3 Assembly 6 consisted of six phases, A through F. In each phase a critical configuration was constructed to simulate a very simple shape such as a slab, cylinder or sphere that could be analyzed with the limited analytical tools available in the 1950s. In each case the configuration consisted of a core region of metal plates surrounded by a thick depleted uranium metal reflector. The average compositions of the core configurations were essentially identical in phases A - F. ZPR-3

  7. ZPR-3 Assembly 12 : A cylindrical assembly of highly enriched uranium, depleted uranium and graphite with an average {sup 235}U enrichment of 21 atom %.

    SciTech Connect

    Lell, R. M.; McKnight, R. D.; Perel, R. L.; Wagschal, J. J.; Nuclear Engineering Division; Racah Inst. of Physics

    2010-09-30

    Over a period of 30 years, more than a hundred Zero Power Reactor (ZPR) critical assemblies were constructed at Argonne National Laboratory. The ZPR facilities, ZPR-3, ZPR-6, ZPR-9 and ZPPR, were all fast critical assembly facilities. The ZPR critical assemblies were constructed to support fast reactor development, but data from some of these assemblies are also well suited for nuclear data validation and to form the basis for criticality safety benchmarks. A number of the Argonne ZPR/ZPPR critical assemblies have been evaluated as ICSBEP and IRPhEP benchmarks. Of the three classes of ZPR assemblies, engineering mockups, engineering benchmarks and physics benchmarks, the last group tends to be most useful for criticality safety. Because physics benchmarks were designed to test fast reactor physics data and methods, they were as simple as possible in geometry and composition. The principal fissile species was {sup 235}U or {sup 239}Pu. Fuel enrichments ranged from 9% to 95%. Often there were only one or two main core diluent materials, such as aluminum, graphite, iron, sodium or stainless steel. The cores were reflected (and insulated from room return effects) by one or two layers of materials such as depleted uranium, lead or stainless steel. Despite their more complex nature, a small number of assemblies from the other two classes would make useful criticality safety benchmarks because they have features related to criticality safety issues, such as reflection by soil-like material. ZPR-3 Assembly 12 (ZPR-3/12) was designed as a fast reactor physics benchmark experiment with an average core {sup 235}U enrichment of approximately 21 at.%. Approximately 68.9% of the total fissions in this assembly occur above 100 keV, approximately 31.1% occur below 100 keV, and essentially none below 0.625 eV - thus the classification as a 'fast' assembly. This assembly is Fast Reactor Benchmark No. 9 in the Cross Section Evaluation Working Group (CSEWG) Benchmark Specifications

  8. Vesta thermal models

    NASA Astrophysics Data System (ADS)

    Formisano, M.; Federico, C.; Coradini, A.

    Vesta thermal evolution and structural models are compared. These models, based on decay of 26Al, 60Fe and long-lived radionuclides (40K, 232Th, 235U and 238U), differ for the delay in injection (Delta td) of 26Al by the nebula in which Vesta was formed. In all models we can see the pristine formation of a metallic core followed by the differentiation of silicatic mantle and we can observe the evolution of the crust. This is in preparation of the Dawn mission that will provide us with constraints on the crust thickness and composition of the crust and underlying mantle.

  9. NUCLEAR DATA REVIEW

    SciTech Connect

    HOLDEN,N.E.

    2004-12-01

    Non-neutron nuclear data are periodically reviewed and evaluated. The recommended values are published in the Table of the Isotopes of the Chemical Rubber Company's Handbook of Chemistry and Physics. A 2004 review has begun to re-examine some data of interest to the International Union of Geological Sciences (IUGS) sub-commission on Geochronology dealing with radioactive decay constants and isotopic abundance ratios. Among the decay constants that are being evaluated are those of the following nuclides: {sup 40}K, {sup 87}Rb, {sup 138}La, {sup 147}Sm, {sup 176}Lu, {sup 174}Hf, {sup 187}Re, {sup 190}Pt, {sup 232}Th, {sup 235}U, {sup 238}U.

  10. (238)U/(235)U isotope ratios of crustal material, rivers and products of hydrothermal alteration: new insights on the oceanic U isotope mass balance.

    PubMed

    Noordmann, Janine; Weyer, Stefan; Georg, R Bastian; Jöns, Svenja; Sharma, Mukul

    2016-01-01

    In this study, the U isotope composition, n((238)U)/n((235)U), of major components of the upper continental crust, including granitic rocks of different age and post-Archaean shales, as well as that of rivers (the major U source to the oceans) was investigated. Furthermore, U isotope fractionation during the removal of U at mid-ocean ridges, an important sink for U from the oceans, was investigated by the analyses of hydrothermal water samples (including low- and high-temperature fluids), low-temperature altered basalts and calcium carbonate veins. All analysed rock samples from the continental crust fall into a limited range of δ(238)U between -0.45 and -0.21 ‰ (relative to NBL CRM 112-A), with an average of -0.30 ± 0.15 ‰ (2 SD, N = 11). Despite differences in catchment lithologies, all major rivers define a relatively narrow range between -0.31 and -0.13 ‰, with a weighted mean isotope composition of -0.27 ‰, which is indistinguishable from the estimate for the upper continental crust (-0.30 ‰). Only some tributary rivers from the Swiss Alps display a slightly larger range in δ(238)U (-0.29 to +0.01 ‰) and lower U concentrations (0.87-3.08 nmol/kg) compared to the investigated major rivers (5.19-11.69 nmol/kg). These findings indicate that only minor net U isotope fractionation occurs during weathering and transport of material from the continental crust to the oceans. Altered basalts display moderately enriched U concentrations (by a factor of 3-18) compared to those typically observed for normal mid-ocean ridge basalts. These, and carbonate veins within altered basalts, show large U isotope fractionation towards both heavy and light U isotope compositions (ranging from -0.63 to +0.27 ‰). Hydrothermal water samples display low U concentrations (0.3-1 nmol/kg) and only limited variations in their U isotope composition (-0.43 ± 0.25 ‰) around the seawater value. Nevertheless, two of the investigated fluids display

  11. (238)U/(235)U isotope ratios of crustal material, rivers and products of hydrothermal alteration: new insights on the oceanic U isotope mass balance.

    PubMed

    Noordmann, Janine; Weyer, Stefan; Georg, R Bastian; Jöns, Svenja; Sharma, Mukul

    2016-01-01

    In this study, the U isotope composition, n((238)U)/n((235)U), of major components of the upper continental crust, including granitic rocks of different age and post-Archaean shales, as well as that of rivers (the major U source to the oceans) was investigated. Furthermore, U isotope fractionation during the removal of U at mid-ocean ridges, an important sink for U from the oceans, was investigated by the analyses of hydrothermal water samples (including low- and high-temperature fluids), low-temperature altered basalts and calcium carbonate veins. All analysed rock samples from the continental crust fall into a limited range of δ(238)U between -0.45 and -0.21 ‰ (relative to NBL CRM 112-A), with an average of -0.30 ± 0.15 ‰ (2 SD, N = 11). Despite differences in catchment lithologies, all major rivers define a relatively narrow range between -0.31 and -0.13 ‰, with a weighted mean isotope composition of -0.27 ‰, which is indistinguishable from the estimate for the upper continental crust (-0.30 ‰). Only some tributary rivers from the Swiss Alps display a slightly larger range in δ(238)U (-0.29 to +0.01 ‰) and lower U concentrations (0.87-3.08 nmol/kg) compared to the investigated major rivers (5.19-11.69 nmol/kg). These findings indicate that only minor net U isotope fractionation occurs during weathering and transport of material from the continental crust to the oceans. Altered basalts display moderately enriched U concentrations (by a factor of 3-18) compared to those typically observed for normal mid-ocean ridge basalts. These, and carbonate veins within altered basalts, show large U isotope fractionation towards both heavy and light U isotope compositions (ranging from -0.63 to +0.27 ‰). Hydrothermal water samples display low U concentrations (0.3-1 nmol/kg) and only limited variations in their U isotope composition (-0.43 ± 0.25 ‰) around the seawater value. Nevertheless, two of the investigated fluids display

  12. 40 kW Stirling engine for solid fuel

    SciTech Connect

    Carlsen, H.; Ammundsen, N.; Traerup, J.

    1996-12-31

    The external combustion in a Stirling engine makes it very attractive for utilization of solid fuels in decentralized combined heat and power (CHP) plants. Only few projects have concentrated on the development of Stirling engines specifically for biomass. In this project a Stirling engine has been designed primarily for utilization of wood chips. Maximum shaft power is 40 kW corresponding to an electric output of 36 kW. Biomass needs more space in the combustion chamber compared to gas and liquid fuels, and a large heat transfer area is necessary. The design of the new Stirling engine has been adapted to the special demands of combustion of wood chips, resulting in a large engine compared to engines for gas or liquid fuels. The engine has four-cylinders arranged in a square. The design is made as a hermetic unit, where the alternator is built into the pressurized crankcase so that dynamic seals are avoided. Grease lubricated bearings are used in a special designed crank mechanism, which eliminates guiding forces on the pistons Helium is used as working gas at 4 MPa mean pressure. The first test of the 40 kW engine with natural gas as fuel has been made in the laboratory, and the results are in agreement with predicted results from simulation programs. The wood chips combustion system has been tested for some time with very promising results. When the laboratory test of the engine is finished, the test of the complete system will be initiated. The paper describes the engine and results from the test program. Expectations to maintenance and operation problems are also discussed.

  13. Prompt fission neutron spectra from fission induced by 1 to 8 MeV neutrons on {sup 235}U and {sup 239}Pu using the double time-of-flight technique

    SciTech Connect

    Noda, S.; Haight, R. C.; Nelson, R. O.; Devlin, M.; O'Donnell, J. M.; Chatillon, A.; Granier, T.; Belier, G.; Taieb, J.; Kawano, T.; Talou, P.

    2011-03-15

    Prompt fission neutron spectra from {sup 235}U and {sup 239}Pu were measured for incident neutron energies from 1 to 200 MeV at the Weapons Neutron Research facility (WNR) of the Los Alamos Neutron Science Center, and the experimental data were analyzed with the Los Alamos model for the incident neutron energies of 1-8 MeV. A CEA multiple-foil fission chamber containing deposits of 100 mg {sup 235}U and 90 mg {sup 239}Pu detected fission events. Outgoing neutrons were detected by the Fast Neutron-Induced {gamma}-Ray Observer array of 20 liquid organic scintillators. A double time-of-flight technique was used to deduce the neutron incident energies from the spallation target and the outgoing energies from the fission chamber. These data were used for testing the Los Alamos model, and the total kinetic energy parameters were optimized to obtain a best fit to the data. The prompt fission neutron spectra were also compared with the Evaluated Nuclear Data File (ENDF/B-VII.0). We calculate average energies from both experimental and calculated fission neutron spectra.

  14. New measurements of (n,γ) and (n,fission) cross sections and capture-to-fission ratios for ^233,235U and ^239Pu using the DANCE 4π BaF2 array

    NASA Astrophysics Data System (ADS)

    Bredeweg, T. A.; Jandel, M.; Fowler, M. M.; Bond, E. M.; Haight, R. C.; Keksis, A. L.; O'Donnell, J. M.; Reifarth, R.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.; Becker, J. A.; Parker, W. E.; Wu, C. Y.; Baker, J. D.; McGrath, C. A.

    2009-10-01

    Accurate neutron nuclear data are important to many issues in stockpile stewardship, nuclear reactor design and re-certification, nuclear non-proliferation and nuclear forensics. Of particular interest are the production and destruction reactions for all of the major and most of the minor actinides. The competition between capture and fission in many of the actinides presents both an obstacle and an opportunity for large γ detector arrays such as DANCE. Additional instrumentation is required to deconvolve the two contributions to the total observed γ-ray spectrum. However, conducting a simultaneous measurement can simplify background treatment and other sources of systematic uncertainty. An outline of the current experimental program will be presented along with results from neutron capture measurements on ^233,235U and ^239Pu.

  15. Distribution of naturally occurring radioactivity and ¹³⁷Cs in the marine sediment of Farasan Island, southern Red Sea, Saudi Arabia.

    PubMed

    Al-Zahrany, A A; Farouk, M A; Al-Yousef, A A

    2012-11-01

    The present work is a part of a project dedicated to measure the marine radioactivity near the Saudi Arabian coasts of the Red Sea and Arabian Gulf for establishing a marine radioactivity database, which includes necessary information on the background levels of both naturally occurring and man-made radionuclides in the marine environment. Farasan Islands is a group of 84 islands (archipelago), under the administration of the Kingdom of Saudi Arabia, in the Red Sea with its main island of Farasan, which is 50 km off the coast of Jazan City. The levels of natural radioactivity of (238)U, (235)U, (226)Ra, (232)Th and (40)K and man-made radionuclides such as (137)Cs in the grab sediment and water samples around Farasan Island have been measured using gamma-ray spectroscopy. The average activity concentrations of (238)U, (235)U, (226)Ra, (232)Th, (40)K and (137)Cs in the sediment samples were found to be 35.46, 1.75, 3.31, 0.92, 34.34 and 0.14 Bq kg(-1), respectively.

  16. Radioactivity in honey of the central Italy.

    PubMed

    Meli, Maria Assunta; Desideri, Donatella; Roselli, Carla; Feduzi, Laura; Benedetti, Claudio

    2016-07-01

    Natural radionuclides and (137)Cs in twenty seven honeys produced in a region of the Central Italy were determined by alpha ((235)U, (238)U, (210)Po, (232)Th and (228)Th) and gamma spectrometry ((137)Cs, (40)K, (226)Ra and (228)Ra). The study was carried out in order to estimate the background levels of natural ((40)K, (238)U and (232)Th and their progeny) and artificial radionuclides ((137)Cs) in various honey samples, as well as to compile a data base for radioactivity levels in that region. (40)K showed a mean activity of 28.1±23.0Bqkg(-1) with a range of 7.28-101Bqkg(-1). The mean of (210)Po activity resulted 0.40±0.46Bqkg(-1) with a range of 0.03-1.98Bqkg(-1). The mean of (238)U activity resulted 0.020±0.010Bqkg(-1). (226)Ra and (228)Ra resulted always <0.34 and <0.57Bqkg(-1) respectively, (235)U, (228)Th and (232)Th were always <0.007Bqkg(-1). (137)Cs resulted <0.10Bqkg(-1) in all samples. The committed effective doses due to (210)Po from ingestion of honey for infants, children and adults account for 0.002-5.13% of the natural radiation exposure in Italy. The honeys produced in Central Italy were of good quality in relation to the studied parameters, confirming the general image of a genuine and healthy food associated to this traditional products.

  17. High-precision calculation of the branching ratio of the 40K decay constant.

    NASA Astrophysics Data System (ADS)

    Jourdan, F.

    2008-12-01

    40K is of great importance in Earth science, particularly for K/Ar, 40Ar/39Ar and K/Ca geochronology. The decay scheme of the 40K includes two different modes of decay, beta and electron capture followed by gamma-ray emission, which yield two different products, 40Ca* and 40Ar*. The relative probability that 40K decay following one of the two schemes is known as the branching ratio. An original method of calculation to obtain the value of the 40K branching ratio (λβ- /λtot) based on the K/Ar technique, is proposed. λβ- /λtot is obtained by combining the 40Ar*/40K value of Fish Canyon sanidine (FCs) secondary standard derived from four primary 40Ar/39Ar standards, with the current best estimates of the age of FCs and the value of the 40K total decay constant. The latest estimation of the 40K total decay constant and the age of FCs by Mundil et al. (2006), through comparison with U/Pb ages, yields a λβ- /λtot value of 89.59 ± 0.03% (1σ; relative error = ± 0.035%). Indirect measurement of the age of FCs by orbital tuning (Kuiper et al., 2008) combined with the value of 40K total decay constant measured by liquid scintillation counting by Kossert and Gunther (2004) yields a statistically indistinguishable value for the branching ratio of 89.61 ± 0.03%, with an average between the two values of 89.60 ± 0.04%. The method proposed here allows can easily be applied to further constrain the value of the 40K branching ratio as future refinements of the 40K decay constant and FCs age are produced, although it is expected that the adopted value will be close to λβ- /λtot = 89.60 ± 0.04%. Kossert and Gunther, 2004. Appl. Radiat. Isot. 60, 459-464. Kuiper et al., 2008. Science 320, 500-504. Mundil et al. 2006, Eos Trans. AGU, 87(52)

  18. Joint determination of 40K decay constants and 40Ar∗/ 40K for the Fish Canyon sanidine standard, and improved accuracy for 40Ar/ 39Ar geochronology

    NASA Astrophysics Data System (ADS)

    Renne, Paul R.; Mundil, Roland; Balco, Greg; Min, Kyoungwon; Ludwig, Kenneth R.

    2010-09-01

    40Ar/ 39Ar and K-Ar geochronology have long suffered from large systematic errors arising from imprecise K and Ar isotopic data for standards and imprecisely determined decay constants for the branched decay of 40K by electron capture and β - emission. This study presents a statistical optimization approach allowing constraints from 40K activity data, K-Ar isotopic data, and pairs of 238U- 206Pb and 40Ar/ 39Ar data for rigorously selected rocks to be used as inputs for estimating the partial decay constants ( λ ɛ and λ β) of 40K and the 40Ar∗/ 40K ratio ( κFCs) of the widely used Fish Canyon sanidine (FCs) standard. This yields values of κFCs = (1.6418 ± 0.0045) × 10 -3, λ ɛ = (0.5755 ± 0.0016) × 10 -10 a -1 and λ β = (4.9737 ± 0.0093) × 10 -10 a -1. These results improve uncertainties in the decay constants by a factor of >4 relative to values derived from activity data alone. Uncertainties in these variables determined by our approach are moderately to highly correlated (cov( κFCs, λ ɛ) = 7.1889 × 10 -19, cov( κFCs, λ β) = -7.1390 × 10 -19, cov( λ ɛ, λ β) = -3.4497 × 10 -26) and one must take account of the covariances in error propagation by either linear or Monte Carlo methods. 40Ar/ 39Ar age errors estimated from these results are significantly reduced relative to previous calibrations. Also, age errors are smaller for a comparable level of isotopic measurement precision than those produced by the 238U/ 206Pb system, because the 40Ar/ 39Ar system is now jointly calibrated by both the 40K and 238U decay constants, and because λ ɛ( 40K) < λ( 238U). Based on this new calibration, the age of the widely used Fish Canyon sanidine standard is 28.305 ± 0.036 Ma. The increased accuracy of 40Ar/ 39Ar ages is now adequate to provide meaningful validation of high-precision U/Pb or astronomical tuning ages in cases where closed system behavior of K and Ar can be established.

  19. Occurrence of natural radioactivity in public water supplies in Germany: (238)U, (234)U, (235)U, (228)RA, (226)RA, (222)RN, (210)PB, (210)PO and gross alpha activity concentrations.

    PubMed

    Beyermann, M; Bünger, T; Schmidt, K; Obrikat, D

    2010-09-01

    The Federal Office for Radiation Protection performed a representative survey on the radiological quality of drinking water in Germany. The aim of this study was to determine regional variations of natural radionuclide concentrations and to estimate radiation exposures caused by drinking water consumption. The study includes analyses of the natural radionuclides (238)U, (234)U, (235)U, (228)Ra, (226)Ra, (222)Rn, (210)Pb, (210)Po and of gross alpha activity concentrations in drinking water from 564 public water supplies. This represents 3 % of all German water supplies providing about 37 Mio. inhabitants. Results on ranges, medians and distributions of radionuclide concentrations of drinking water as well as age-dependent ingestion and inhalation doses estimated for members of the public are presented. Generally, the dose due to uranium isotopes is negligibly low. Radiation exposures are predominantly caused by (222)Rn, (228)Ra, (210)Po and (210)Pb. The ingestion dose deduced for adults (>17 a) and infants (0-1 a) is dominated by (222)Rn and (228)Ra, respectively. A gross alpha activity analysis procedure using liquid scintillation counting has been tested. Measured gross alpha activities values were found to be well related to the summarised activities of (238)U, (234)U, (226)Ra and (210)Po.

  20. Energy Dependence of Fission Product Yields from 235U, 238U and 239Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

    NASA Astrophysics Data System (ADS)

    Gooden, M.; Arnold, C.; Bredeweg, T.; Vieira, D.; Wilhelmy, J.; Tonchev, A.; Stoyer, M.; Bhike, M.; Krishichayan, F.; Tornow, W.; Fowler, M.

    2015-10-01

    Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements has been performed. The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi-monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of fission counting using specially designed dual-fission chambers and ?-ray counting. Each dual-fission chamber is a back-to-back ionization chamber encasing an activation target in the center with thin deposits of the same target isotope in each chamber. This method allows for the direct measurement of the total number of fissions in the activation target with no reference to the fission cross-section, thus reducing uncertainties. ?-ray counting of the activation target was performed on well-shielded HPGe detectors over a period of 2 months post irradiation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6, 5.5, 7.5, 8.9 and 14.8 MeV. These results are compared to previous measurements and theoretical estimates. This work was performed under the auspices of the USDoE by Los Alamos National Security, LLC under Contract DE-AC52-06NA25396.

  1. New measurements of (n,γ) and (n,fission) cross sections and capture-to-fission ratios for ^233,235U and ^239Pu using the DANCE 4π BaF2 array

    NASA Astrophysics Data System (ADS)

    Bredeweg, T. A.; Jandel, M.; Fowler, M. M.; Bond, E. M.; Haight, R. C.; Keksis, A. L.; O'Donnell, J. M.; Reifarth, R.; Rundberg, R. S.; Slemmons, A. K.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.; Becker, J. A.; Wu, C. Y.; Baker, J. D.; McGrath, C. A.

    2010-11-01

    Accurate neutron-induced reaction data are important to many issues in stockpile stewardship, nuclear reactor design and re-certification, nuclear non-proliferation and nuclear forensics. Of particular interest are the production and destruction reactions for all of the major and most of the minor actinides, including both neutron-induced capture and fission. The competition between capture and fission presents both an obstacle and an opportunity for large γ detector arrays such as the DANCE array (Detector for Advanced Neutron Capture Experiments), which cannot clearly differentiate γ-rays resulting from the two exit channels. With the addition of a high efficiency, 4π fission-tagging detector it is possible to deconvolve the two contributions to the total γ-ray spectrum. Using these tools we are able to conduct simultaneous fission/capture measurements which can simplify background treatment and other sources of systematic uncertainty. An outline of the current experimental program will be presented along with results from neutron capture measurements on ^233,235U and ^239Pu.

  2. Porosity of the melting zone and variations in the solid mantle upwelling rate beneath Hawaii: Inferences from {sup 238}U-{sup 230}Th-{sup 226}Ra and {sup 235}U-{sup 231}Pa disequilibria

    SciTech Connect

    Sims, K.W.W.; DePaolo, D.J.; Murrell, M.T.; Baldridge, W.S.; Goldstein, S.; Clague, D.; Jull, M.

    1999-12-01

    Measurements of {sup 238}U-{sup 230}Th-{sup 226}Ra and {sup 235}U-{sup 231}Pa disequilibria in a suite of tholeiitic-to-basanitic lavas provide estimates of porosity, solid mantle upwelling rate and melt transport times beneath Hawaii. The observation that ({sup 230}Th/{sup 238}U) {gt} 1 indicates that garnet is required as a residual phase in the magma sources for all of the lavas. Both chromatographic porous flow and dynamic melting of a garnet peridotite source can adequately explain the combined U-Th-Ra and U-Pa data for these Hawaiian basalts. For chromatographic porous flow, the calculated maximum porosity in the melting zone ranges from 0.3--3% for tholeiites and 0.1--1% for alkali basalts and basanites, and solid mantle upwelling rates range from 40 to 100 cm/yr for tholeiites and from 1 to 3 cm/yr for basanites. For dynamic melting, the escape or threshold porosity is 0.5--2% for tholeiites and 0.1--0.8% for alkali basalts and basanites, and solid mantle upwelling rates range from 10 to 30 cm/yr for tholeiites and from 0.1 to 1 cm/yr for basanites. Assuming a constant melt productivity, calculated total melt fractions range from 15% for the tholeiitic basalts to 3% for alkali basalts and basanites.

  3. Ground gamma-ray survey of the Solforata gas discharge area, Alban Hills-Italy: a comparison between field and laboratory measurements.

    PubMed

    Di Paolo, Federico; Plastino, Wolfango; Povinec, Pavel P; Bella, Francesco; Budano, Antonio; De Vincenzi, Mario; Laubenstein, Matthias; Ruggieri, Federico

    2013-01-01

    Measurements of environmental radioactivity by HPGe gamma-spectrometry were carried out with the aim of investigating the distribution of natural radionuclides in a volcanic area and to compare two different methodologies - an in situ gamma-survey of the area and high accuracy laboratory measurements of soil samples. Results demonstrate good performance of the in situ technique, also confirmed by a correlation analysis between the results obtained by the two methodologies. A volcanic gas discharge area was chosen as the test site for the presence of natural long-lived radionuclides such as (40)K and (238)U, (235)U and (232)Th, and their decay chain members. Clear evidence of (222)Rn degassing in the area was confirmed by (226)Ra values measured by the in situ technique. Higher (40)K values measured by the in situ technique may be attributed to the presence of vegetation in the study area. PMID:22982169

  4. Body Potassium Content and Radiation Dose from 40K for the Urals Population (Russia).

    PubMed

    Tolstykh, Evgenia I; Degteva, Marina O; Bougrov, Nikolay G; Napier, Bruce A

    2016-01-01

    Long-term whole-body monitoring of radionuclides in residents of the Urals Region has been performed at the Urals Research Center for Radiation Medicine (URCRM, Chelyabinsk). Quantification of 40K was achieved by measuring the 40K photopeak with four phoswich detectors in whole body counter SICH-9.1M. The current study presents the results of 40K measurements in 3,651 women and 1,961 t-test; U-test men aged 11-90; measurements were performed in 2006-2014. The residents belonged to two ethnic groups, Turkic (Tatar, Bashkir) and Slavs (mainly Russian). The levels of 40K-body contents depend upon gender, age, and body mass. Significant ethnic-differences were not found in 40K-body contents and 40K concentrations in terms of Bq per kg of body weight (in groups homogenous by age and gender). Both 40K-body contents and concentrations were significantly higher in men than in women in all age-groups; the difference was about 25%. The measured 40K-body content in men of 20-50 years was about 4200 Bq (134 g of K) and about 3000 Bq (95 g of K) in women. By the age of 80 these values decreased to 3200 Bq (102 g of K) in men and 2500 Bq (80 g of K) in women. Annual dose rates were maximal in the age group of 20-30 years- 0.16 mGy/y for men and 0.13 mGy/y for women. Further, the dose-rates decreased with age and in the groups of 60-80 years were 0.13 mGy/y for men and 0.10 mGy/y for women. Within groups homogeneous by age and gender, individual dose rates are described by a normal statistical distribution. The coefficient of variation ranges from 9 to 14%, and on the average is 12.5%. Doses from naturally occurring 40K accumulated over 70 years were found to be 9.9 mGy for men and 8.3 mGy for women; over 90 years - 12.5 and 10.4 mGy.

  5. Body Potassium Content and Radiation Dose from 40K for the Urals Population (Russia)

    PubMed Central

    Tolstykh, Evgenia I.; Degteva, Marina O.; Bougrov, Nikolay G.; Napier, Bruce A.

    2016-01-01

    Long-term whole-body monitoring of radionuclides in residents of the Urals Region has been performed at the Urals Research Center for Radiation Medicine (URCRM, Chelyabinsk). Quantification of 40K was achieved by measuring the 40K photopeak with four phoswich detectors in whole body counter SICH-9.1M. The current study presents the results of 40K measurements in 3,651 women and 1,961 t-test; U-test men aged 11–90; measurements were performed in 2006–2014. The residents belonged to two ethnic groups, Turkic (Tatar, Bashkir) and Slavs (mainly Russian). The levels of 40K-body contents depend upon gender, age, and body mass. Significant ethnic-differences were not found in 40K-body contents and 40K concentrations in terms of Bq per kg of body weight (in groups homogenous by age and gender). Both 40K-body contents and concentrations were significantly higher in men than in women in all age-groups; the difference was about 25%. The measured 40K-body content in men of 20–50 years was about 4200 Bq (134 g of K) and about 3000 Bq (95 g of K) in women. By the age of 80 these values decreased to 3200 Bq (102 g of K) in men and 2500 Bq (80 g of K) in women. Annual dose rates were maximal in the age group of 20–30 years– 0.16 mGy/y for men and 0.13 mGy/y for women. Further, the dose-rates decreased with age and in the groups of 60–80 years were 0.13 mGy/y for men and 0.10 mGy/y for women. Within groups homogeneous by age and gender, individual dose rates are described by a normal statistical distribution. The coefficient of variation ranges from 9 to 14%, and on the average is 12.5%. Doses from naturally occurring 40K accumulated over 70 years were found to be 9.9 mGy for men and 8.3 mGy for women; over 90 years - 12.5 and 10.4 mGy. PMID:27111330

  6. Neutron Total Cross Sections of {sup 235}U From Transmission Measurements in the Energy Range 2 keV to 300 keV and Statistical Model Analysis of the Data

    SciTech Connect

    Derrien, H.; Harvey, J.A.; Larson, N.M.; Leal, L.C.; Wright, R.Q.

    2000-05-01

    The average {sup 235}U neutron total cross sections were obtained in the energy range 2 keV to 330 keV from high-resolution transmission measurements of a 0.033 atom/b sample.1 The experimental data were corrected for the contribution of isotope impurities and for resonance self-shielding effects in the sample. The results are in very good agreement with the experimental data of Poenitz et al.4 in the energy range 40 keV to 330 keV and are the only available accurate experimental data in the energy range 2 keV to 40 keV. ENDF/B-VI evaluated data are 1.7% larger. The SAMMY/FITACS code 2 was used for a statistical model analysis of the total cross section, selected fission cross sections and data in the energy range 2 keV to 200 keV. SAMMY/FITACS is an extended version of SAMMY which allows consistent analysis of the experimental data in the resolved and unresolved resonance region. The Reich-Moore resonance parameters were obtained 3 from a SAMMY Bayesian fits of high resolution experimental neutron transmission and partial cross section data below 2.25 keV, and the corresponding average parameters and covariance data were used in the present work as input for the statistical model analysis of the high energy range of the experimental data. The result of the analysis shows that the average resonance parameters obtained from the analysis of the unresolved resonance region are consistent with those obtained in the resolved energy region. Another important result is that ENDF/B-VI capture cross section could be too small by more than 10% in the energy range 10 keV to 200 keV.

  7. NEUTRON TOTAL CROSS SECTIONS OF 235U FROM TRANSMISSION MEASUREMENTS IN THE ENERGY RANGE 2 keV to 300 keV AND STATISTICAL MODEL ANALYSIS OF THE DATA

    SciTech Connect

    Derrien, H.

    2000-05-22

    The average {sup 235}U neutron total cross sections were obtained in the energy range 2 keV to 330 keV from high-resolution transmission measurements of a 0.033 atom/b sample. The experimental data were corrected for the contribution of isotope impurities and for resonance self-shielding effects in the sample. The results are in very good agreement with the experimental data of Poenitz et al. in the energy range 40 keV to 330 keV and are the only available accurate experimental data in the energy range 2 keV to 40 keV. ENDF/B-VI evaluated data are 1.7% larger. The SAMMY/FITACS code was used for a statistical model analysis of the total cross section, selected fission cross sections and {alpha} data in the energy range 2 keV to 200 keV. SAMMY/FITACS is an extended version of SAMMY which allows consistent analysis of the experimental data in the resolved and unresolved resonance region. The Reich-Moore resonance parameters were obtained from a SAMMY Bayesian fits of high resolution experimental neutron transmission and partial cross section data below 2.25 keV, and the corresponding average parameters and covariance data were used in the present work as input for the statistical model analysis of the high energy range of the experimental data. The result of the analysis shows that the average resonance parameters obtained from the analysis of the unresolved resonance region are consistent with those obtained in the resolved energy region. Another important result is that ENDF/B-VI capture cross section could be too small by more than 10% in the energy range 10 keV to 200 keV.

  8. Beta and gamma decay heat measurements between 0.1s - 50,000s for neturon fission of {sup 235}U, {sup 238}U and {sup 239}Pu. Progress report, June 1, 1992--December 31, 1994

    SciTech Connect

    Schier, W.A.; Couchell, G.P.

    1997-05-01

    In the investigations reported here, a helium-jet/tape-transport system was used for the rapid transfer of fission products to a low-background environment where their aggregate beta and gamma-ray spectra were measured as a function of delay time after neutron induced fission of {sup 235}U, {sup 238}U and {sup 239}Pu. Beta and gamma-ray energy distributions have been deduced for delay times as short as 0.2 s and extending out to 100,000s. Instrumentation development during the initial phase of the project included: (1) assembly and characterization of a NaI(Tl) spectrometer for determining aggregate gamma-ray energy distributions, (2) development and characterization of a beta spectrometer (having excellent gamma-ray rejection) for measuring aggregate beta-particle energy distributions, (3) assembly and characterization of a Compton-suppressed HPGe spectrometer for determining gamma-ray intensities of individual fission products to deduce fission-product yields. Spectral decomposition and analysis codes were developed for deducing energy distributions from measured aggregate beta and gamma spectra. The aggregate measurements in the time interval 0.2 - 20s after fission are of special importance since in this region data from many short-lived nuclei are missing and summation calculations in this region rely on model calculations for a large fraction of their predicted beta and gamma decay heat energy spectra. Comparison with ENDF/B-VI fission product data was performed in parallel with the measurements through a close collaboration with Dr. T. England at LANL, assisted by one of our graduate students. Such aggregate measurements provide tests of the Gross Theory of beta decay used to calculated missing contributions to this data base. Fission-product yields deduced from the HPGe studies will check the accuracy of the semi-empirical Gaussian dispersion model used presently by evaluators in the absence of measured yields.

  9. Energy Dependence of Fission Product Yields from 235U, 238U and 239Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

    NASA Astrophysics Data System (ADS)

    Gooden, M. E.; Arnold, C. W.; Becker, J. A.; Bhatia, C.; Bhike, M.; Bond, E. M.; Bredeweg, T. A.; Fallin, B.; Fowler, M. M.; Howell, C. R.; Kelley, J. H.; Krishichayan; Macri, R.; Rusev, G.; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P.; Tornow, W.; Vieira, D. J.; Wilhelmy, J. B.

    2016-01-01

    Fission Product Yields (FPY) have historically been one of the most observable features of the fission process. They are known to have strong variations that are dependent on the fissioning species, the excitation energy, and the angular momentum of the compound system. However, consistent and systematic studies of the variation of these FPY with energy have proved challenging. This is caused primarily by the nature of the experiments that have traditionally relied on radiochemical procedures to isolate specific fission products. Although radiochemical procedures exist that can isolate all products, each element presents specific challenges and introduces varying degrees of systematic errors that can make inter-comparison of FPY uncertain. Although of high importance in fields such as nuclear forensics and Stockpile Stewardship, accurate information about the energy dependence of neutron induced FPY are sparse, due primarily to the lack of suitable monoenergetic neutron sources. There is a clear need for improved data, and to address this issue, a collaboration was formed between Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL) and the Triangle Universities Nuclear Laboratory (TUNL) to measure the energy dependence of FPY for 235U, 238U and 239Pu. The measurements have been performed at TUNL, using a 10 MV Tandem Van de Graaff accelerator to produce monoenergetic neutrons at energies between 0.6 MeV to 14.8 MeV through a variety of reactions. The measurements have utilized a dual-fission chamber, with thin (10-100 μg/cm2) reference foils of similar material to a thick (100-400 mg) activation target held in the center between the chambers. This method allows for the accurate determination of the number of fissions that occurred in the thick target without requiring knowledge of the fission cross section or neutron fluence on target. Following activation, the thick target was removed from the dual-fission chamber and gamma

  10. Energy dependence of fission product yields from 235U, 238U and 239Pu for incident neutron energies between 0.5 and 14.8 MeV

    DOE PAGES

    Gooden, M. E.; Arnold, C. W.; Becker, J. A.; Bhatia, C.; Bhike, M.; Bond, E. M.; Bredeweg, T. A.; Fallin, B.; Fowler, M. M.; Howell, C. R.; et al

    2016-01-06

    In this study, Fission Product Yields (FPY) have historically been one of the most observable features of the fission process. They are known to have strong variations that are dependent on the fissioning species, the excitation energy, and the angular momentum of the compound system. However, consistent and systematic studies of the variation of these FPY with energy have proved challenging. This is caused primarily by the nature of the experiments that have traditionally relied on radiochemical procedures to isolate specific fission products. Although radiochemical procedures exist that can isolate all products, each element presents specific challenges and introduces varyingmore » degrees of systematic errors that can make inter-comparison of FPY uncertain. Although of high importance in fields such as nuclear forensics and Stockpile Stewardship, accurate information about the energy dependence of neutron induced FPY are sparse, due primarily to the lack of suitable monoenergetic neutron sources. There is a clear need for improved data, and to address this issue, a collaboration was formed between Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL) and the Triangle Universities Nuclear Laboratory (TUNL) to measure the energy dependence of FPY for 235U, 238U and 239Pu. The measurements have been performed at TUNL, using a 10 MV Tandem Van de Graaff accelerator to produce monoenergetic neutrons at energies between 0.6 MeV to 14.8 MeV through a variety of reactions. The measurements have utilized a dual-fission chamber, with thin (10-100 μg/cm2) reference foils of similar material to a thick (100-400 mg) activation target held in the center between the chambers. This method allows for the accurate determination of the number of fissions that occurred in the thick target without requiring knowledge of the fission cross section or neutron fluence on target. Following activation, the thick target was removed from the dual

  11. ZPR-3 Assembly 11 : A cylindrical sssembly of highly enriched uranium and depleted uranium with an average {sup 235}U enrichment of 12 atom % and a depleted uranium reflector.

    SciTech Connect

    Lell, R. M.; McKnight, R. D.; Tsiboulia, A.; Rozhikhin, Y.; National Security; Inst. of Physics and Power Engineering

    2010-09-30

    Over a period of 30 years, more than a hundred Zero Power Reactor (ZPR) critical assemblies were constructed at Argonne National Laboratory. The ZPR facilities, ZPR-3, ZPR-6, ZPR-9 and ZPPR, were all fast critical assembly facilities. The ZPR critical assemblies were constructed to support fast reactor development, but data from some of these assemblies are also well suited for nuclear data validation and to form the basis for criticality safety benchmarks. A number of the Argonne ZPR/ZPPR critical assemblies have been evaluated as ICSBEP and IRPhEP benchmarks. Of the three classes of ZPR assemblies, engineering mockups, engineering benchmarks and physics benchmarks, the last group tends to be most useful for criticality safety. Because physics benchmarks were designed to test fast reactor physics data and methods, they were as simple as possible in geometry and composition. The principal fissile species was {sup 235}U or {sup 239}Pu. Fuel enrichments ranged from 9% to 95%. Often there were only one or two main core diluent materials, such as aluminum, graphite, iron, sodium or stainless steel. The cores were reflected (and insulated from room return effects) by one or two layers of materials such as depleted uranium, lead or stainless steel. Despite their more complex nature, a small number of assemblies from the other two classes would make useful criticality safety benchmarks because they have features related to criticality safety issues, such as reflection by soil-like material. ZPR-3 Assembly 11 (ZPR-3/11) was designed as a fast reactor physics benchmark experiment with an average core {sup 235}U enrichment of approximately 12 at.% and a depleted uranium reflector. Approximately 79.7% of the total fissions in this assembly occur above 100 keV, approximately 20.3% occur below 100 keV, and essentially none below 0.625 eV - thus the classification as a 'fast' assembly. This assembly is Fast Reactor Benchmark No. 8 in the Cross Section Evaluation Working Group

  12. McDonnell 40-kW Giromill Wind System. Phase II. Fabrication and test

    SciTech Connect

    Brulle, R

    1980-06-01

    A 40 kW vertical axis windmill called a ''Giromill'' was fabricated, erected, and tested. The system design is described as well as some design changes made during fabrication. Manufacturing cost estimates are updated. Fabrication of the turbine blades, support arms, and fixed and rotating tower is described as well as the tests. Testing included control systems acceptance tests; Giromill system acceptance tests; structural, mechanical, control system and electric generation operational tests; and performance tests connected to the utility grid. (LEW)

  13. Evidence for superconductivity above 40 K in the La-Ba-Cu-O compound system

    NASA Technical Reports Server (NTRS)

    Chu, C. W.; Hor, P. H.; Meng, R. L.; Gao, L.; Huang, Z. J.

    1987-01-01

    An apparent superconducting transition with an onset temperature above 40 K has been detected under pressure in the La-Ba-Cu-O compound system synthesized directly from a solid-state reaction of La2O3, CuO, and BaCO3 followed by a decomposition of the mixture in a reduced atmosphere. The experiment is described and the results of effects of magnetic field and pressure are discussed.

  14. Operation result of 40kW class MCFC pilot plant

    SciTech Connect

    Saitoh, H.; Hatori, S.; Hosaka, M.; Uematsu, H.

    1996-12-31

    Ishikawajima-Harima Heavy Industries Co., Ltd. developed unique Molten Carbonate Fuel Cell (MCFC) system based on our original concept. To demonstrate the possibility of this system, based on MCFC technology of consigned research from New Energy and Industrial Technology Development Organization (NEDO) in Japan, we designed 40kW class MCFC pilot plant which had all equipments required as a power plant and constructed in our TO-2 Technical Center. This paper presents the test results of the plant.

  15. Spectral interference corrections for the measurement of (238)U in materials rich in thorium by a high resolution gamma-ray spectrometry.

    PubMed

    Yücel, H; Solmaz, A N; Köse, E; Bor, D

    2009-11-01

    In this study, the spectral interferences are investigated for the analytical peaks at 63.3 keV of (234)Th and 1001.0 keV of (234m)Pa, which are often used in the measurement of (238)U activity by the gamma-ray spectrometry. The correction methods are suggested to estimate the net peak areas of the gamma-rays overlapping the analytical peaks, due to the contribution of (232)Th that may not be negligible in materials rich in natural thorium. The activity results for the certified reference materials (CRMs) containing U and Th were measured with a well type Ge detector. The self-absorption and true coincidence-summing (TCS) effects were also taken into account in the measurements. It is found that ignoring the contributions of the interference gamma-rays of (232)Th and (235)U to the mixed peak at 63.3 keV of (234)Th ((238)U) leads to the remarkably large systematic influence of 0.8-122% in the measured (238)U activity, but in case of ignoring the contribution of (232)Th via the interference gamma-ray at 1000.7 keV of (228)Ac to the mixed peak at 1001 keV of (234m)Pa ((238)U) results in relatively smaller systematic influence of 0.05-3%, depending on thorium contents in the samples. The present results showed that the necessary correction for the spectral interferences besides self-absorption and TCS effects is also very important to obtain more accurate (238)U activity results. Additionally, if one ignores the contribution of (232)Th to both (238)U and (40)K activities in materials, the maximum systematic influence on the effective radiation dose is estimated to be ~6% and ~1% via the analytical peaks at 63.3 and 1001 keV for measurement of the (238)U activity, respectively. PMID:19683454

  16. Certified Reference Material IAEA-446 for radionuclides in Baltic Sea seaweed.

    PubMed

    Pham, M K; Benmansour, M; Carvalho, F P; Chamizo, E; Degering, D; Engeler, C; Gascó, C; Gwynn, J P; Harms, A V; Hrnecek, E; Ibanez, F L; Ilchmann, C; Ikaheimonen, T; Kanisch, G; Kloster, M; Llaurado, M; Mauring, A; Møller, B; Morimoto, T; Nielsen, S P; Nies, H; Norrlid, L D R; Pettersson, H B L; Povinec, P P; Rieth, U; Samuelsson, C; Schikowski, J; Silobritiene, B V; Smedley, P A; Suplinska, M; Vartti, V-P; Vasileva, E; Wong, J; Zalewska, T; Zhou, W

    2014-05-01

    A Certified Reference Material (CRM) for radionuclides in seaweed (Fucus vesiculosus) from the Baltic Sea (IAEA-446) is described and the results of the certification process are presented. The (40)K, (137)Cs, (234)U and (239+240)Pu radionuclides were certified for this material, and information values for 12 other radionuclides ((90)Sr, (99)Tc, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (230)Th, (232)Th, (235)U, (238)U, (239)Pu and (240)Pu) are presented. The CRM can be used for Quality Assurance/Quality Control of analysis of radionuclides in seaweed and other biota samples, as well as for development and validation of analytical methods, and for training purposes.

  17. Certified Reference Material IAEA-446 for radionuclides in Baltic Sea seaweed.

    PubMed

    Pham, M K; Benmansour, M; Carvalho, F P; Chamizo, E; Degering, D; Engeler, C; Gascó, C; Gwynn, J P; Harms, A V; Hrnecek, E; Ibanez, F L; Ilchmann, C; Ikaheimonen, T; Kanisch, G; Kloster, M; Llaurado, M; Mauring, A; Møller, B; Morimoto, T; Nielsen, S P; Nies, H; Norrlid, L D R; Pettersson, H B L; Povinec, P P; Rieth, U; Samuelsson, C; Schikowski, J; Silobritiene, B V; Smedley, P A; Suplinska, M; Vartti, V-P; Vasileva, E; Wong, J; Zalewska, T; Zhou, W

    2014-05-01

    A Certified Reference Material (CRM) for radionuclides in seaweed (Fucus vesiculosus) from the Baltic Sea (IAEA-446) is described and the results of the certification process are presented. The (40)K, (137)Cs, (234)U and (239+240)Pu radionuclides were certified for this material, and information values for 12 other radionuclides ((90)Sr, (99)Tc, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (230)Th, (232)Th, (235)U, (238)U, (239)Pu and (240)Pu) are presented. The CRM can be used for Quality Assurance/Quality Control of analysis of radionuclides in seaweed and other biota samples, as well as for development and validation of analytical methods, and for training purposes. PMID:24291528

  18. Natural and man-made radioactivity in soils and plants around the research reactor of Inshass.

    PubMed

    Higgy, R H; Pimpl, M

    1998-12-01

    The specific radioactivities of the U-series, 232Th, 137Cs and 40K were measured in soil samples around the Inshass reactor in Cairo, using a gamma-ray spectrometer with a HpGe detector. The alpha activity of 238U, 234U and 235U was measured in the same soil samples by surface barrier detectors after radiochemical separation and the obtained results were compared with the specific activities determined by gamma-measurements. The alpha-activity of 238Pu, 239+240Pu, 241Am, 242Cm and 244Cm was measured after radiochemical separation by surface barrier detectors for both soil and plant samples. Then beta-activity of 241Pu was measured using liquid scintillation spectrometry. PMID:9776618

  19. Investigation of the radiological impact on the coastal environment surrounding a fertilizer plant.

    PubMed

    El Samad, O; Aoun, M; Nsouli, B; Khalaf, G; Hamze, M

    2014-07-01

    This investigation was carried out in order to assess the marine environmental radioactive pollution and the radiological impact caused by a large production plant of phosphate fertilizer, located in the Lebanese coastal zone. Natural radionuclides ((238)U, (235)U, (232)Th, (226)Ra, (210)Po, (210)Pb, (40)K) and anthropogenic (137)Cs were measured by alpha and gamma spectrometry in seawater, sediment, biota and coastal soil samples collected from the area impacted by this industry. The limited environmental monitoring program within 2 km of the plant indicates localized contamination with radionuclides of the uranium decay chain mainly due to the transport, the storage of raw materials and the free release of phosphogypsum waste.

  20. Investigation of the radiological impact on the coastal environment surrounding a fertilizer plant.

    PubMed

    El Samad, O; Aoun, M; Nsouli, B; Khalaf, G; Hamze, M

    2014-07-01

    This investigation was carried out in order to assess the marine environmental radioactive pollution and the radiological impact caused by a large production plant of phosphate fertilizer, located in the Lebanese coastal zone. Natural radionuclides ((238)U, (235)U, (232)Th, (226)Ra, (210)Po, (210)Pb, (40)K) and anthropogenic (137)Cs were measured by alpha and gamma spectrometry in seawater, sediment, biota and coastal soil samples collected from the area impacted by this industry. The limited environmental monitoring program within 2 km of the plant indicates localized contamination with radionuclides of the uranium decay chain mainly due to the transport, the storage of raw materials and the free release of phosphogypsum waste. PMID:23768871

  1. Observation of 2D Fermionic Mott Insulators of 40K with Single-Site Resolution

    NASA Astrophysics Data System (ADS)

    Cheuk, Lawrence W.; Nichols, Matthew A.; Lawrence, Katherine R.; Okan, Melih; Zhang, Hao; Zwierlein, Martin W.

    2016-06-01

    We report on the site-resolved observation of characteristic states of the two-dimensional repulsive Fermi-Hubbard model, using ultracold 40K atoms in an optical lattice. By varying the tunneling, interaction strength, and external confinement, we realize metallic, Mott-insulating, and band-insulating states. We directly measure the local moment, which quantifies the degree of on-site magnetization, as a function of temperature and chemical potential. Entropies per particle as low as 0.99 (6 )kB indicate that nearest-neighbor antiferromagnetic correlations should be detectable using spin-sensitive imaging.

  2. Metrological traceability for AC High-Voltage in Inmetro up to 40 kV

    NASA Astrophysics Data System (ADS)

    Vitorio, P. C. O.; de Lima, V. R.; Borges Filho, O.; de Souza, L. A. A.; Asencios, O. W. G.

    2016-07-01

    This paper refers to a project carried out in Inmetro aiming to provide internal metrological traceability for 60 Hz AC High-Voltage up to 40 kV. It presents details about the method used, its equations and obtained results. A capacitance and tanb bridge, with a built-in current comparator, was used in combination with two standard capacitors to calibrate a standard potential transformer (PT), both in ratio and phase angle. The results obtained by Inmetro showed good agreement with PTB ones, for the same PT. The maximum estimated uncertainty was 0,0049% for ratio error and 104 μrad for phase angle error.

  3. Exploring an ultracold Fermi-Fermi mixture: interspecies Feshbach resonances of ^6Li-^40K

    NASA Astrophysics Data System (ADS)

    Schreck, Florian

    2008-03-01

    We report on the observation of interspecies Feshbach resonances in an ultracold mixture of two fermionic species, ^6Li and ^40K. Interpretation of the data unambiguously assigns molecular bound states to the various resonances and fully characterizes the ground-state scattering properties in any combination of spin states. Using this knowledge we hope to be able to produce ^6Li-^40K molecules, cool them to quantum degeneracy, and study their BEC-BCS crossover. In collaboration with: F. Schreck, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria; E. Wille, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria and Institut fuer Experimentalphysik und Forschungszentrum fuer Quantenphysik, Universitaet Innsbruck, 6020 Innsbruck, Austria; F.M. Spiegelhalder, G. Kerner, D. Naik, A. Trenkwalder, G. Hendl, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria; R. Grimm, Institut fuer Quantenoptik und Quanteninformation, Oesterreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria and Institut fuer Experimentalphysik und Forschungszentrum fuer Quantenphysik, Universitaet Innsbruck, 6020 Innsbruck, Austria; T.G. Tiecke, J.T.M. Walraven,Van der Waals-Zeeman Institute of the University of Amsterdam, 1018 XE, The Netherlands; S.J.J.M.F. Kokkelmans, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; E. Tiesinga, P.S. Julienne, Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, Maryland 20899-8423, USA

  4. Rotational Spectroscopy on Ultracold 23 Na40 K Ground State Molecules

    NASA Astrophysics Data System (ADS)

    Will, Sebastian; Park, Jee Woo; Yan, Zoe; Loh, Huanqian; Zwierlein, Martin

    2016-05-01

    Ultracold molecules with controllable dipolar long-range interactions will open up new routes for quantum simulation and the creation of novel states of matter. In particular, the molecules' rich internal degrees of freedom allow for versatile control of intermolecular interactions by applying static electric and microwave fields. Starting from an ultracold, spin-polarized ensemble of trapped fermionic 23 Na40 K molecules in the absolute ground state, we perform microwave spectroscopy on the first rotationally excited state for a range of magnetic and electric fields. Extracting the rotational and hyperfine coupling constants, we comprehensively understand the observed spectra. Following the coherent transfer of the entire ensemble of chemically stable 23 Na40 K molecules to the first rotationally excited state, we observe a lifetime of more than 3 sec, comparable to the lifetime in the rovibrational ground state. The collisional stability of excited rotational states opens up intriguing prospects for the control of intermolecular van-der-Waals interactions via electric fields.

  5. (137)Cs, (40)K and (210)Po in marine mammals from the southern Baltic Sea.

    PubMed

    Ciesielski, Tomasz; Góral, Marta; Szefer, Piotr; Jenssen, Bjørn Munro; Bojanowski, Ryszard

    2015-12-15

    This study provides information on baseline concentrations of the radionuclides Cesium-137, Potassium-40 and Polonium-210 in sea mammals from the Baltic Sea. The radionuclides were analyzed in the liver, kidney and muscle of harbor porpoises, striped dolphins, and gray and ringed seals from the Polish coast by γ- and α-spectrometry. Median (137)Cs activities were 14.8, 13.2 and 23.2 Bq kg(-1) w.w. in the liver, kidney and muscles, respectively. Activities of (40)K and (210)Po in the respective tissues were found to be 79.1, 79.8 and 111 Bq kg(-1) for (40)K and 58.1, 59.2 and 32.9 Bq kg(-1) for (210)Po. The measured (137)Cs concentrations were extraordinarily high in comparison to those reported in sea mammals from other locations. However, dose assessments did not imply health effects from (137)Cs exposure in Baltic Sea mammals. Correlations between (137)Cs tissue activities and reported sea water concentrations highlight the potential use of marine mammals for biomonitoring purposes. PMID:26456908

  6. Dynamic nuclear polarization at 40 kHz magic angle spinning.

    PubMed

    Chaudhari, Sachin R; Berruyer, Pierrick; Gajan, David; Reiter, Christian; Engelke, Frank; Silverio, Daniel L; Copéret, Christophe; Lelli, Moreno; Lesage, Anne; Emsley, Lyndon

    2016-04-21

    DNP-enhanced solid-state NMR spectroscopy under magic angle spinning (MAS) is rapidly developing into a powerful analytical tool to investigate the structure of a wide range of solid materials, because it provides unsurpassed sensitivity gains. Most developments and applications of DNP MAS NMR were so far reported at moderate spinning frequencies (up to 14 kHz using 3.2 mm rotors). Here, using a 1.3 mm MAS DNP probe operating at 18.8 T and ∼100 K, we show that signal amplification factors can be increased by up to a factor two when using smaller volume rotors as compared to 3.2 mm rotors, and report enhancements of around 60 over a range of sample spinning rates from 10 to 40 kHz. Spinning at 40 kHz is also shown to increase (29)Si coherence lifetimes by a factor three as compared to 10 kHz, substantially increasing sensitivity in CPMG type experiments. The contribution of quenching effects to the overall sensitivity gain at very fast MAS is evaluated, and applications are reported on a functionalised mesostructured organic-inorganic material.

  7. Body K and 40K in Chinese subjects measured with a whole-body counter

    SciTech Connect

    Lan, C.Y.; Weng, P.S. )

    1989-11-01

    More than 380 Chinese adults of both sexes were studied for their total body K and 40K using the National Tsing Hua University whole-body counter. The K values were found to have an average of 1.75 {plus minus} 0.4 g K kg-1 body weight for males and 1.41 {plus minus} 0.1 g K kg-1 body weight for females. The average K value for both sexes was 1.69 {plus minus} 0.4 g K kg-1 body weight. The annual absorbed dose for the average male was calculated to be 0.21 {plus minus} 0.04 mGy and for the average female was 0.17 {plus minus} 0.01 mGy. The average for both sexes was 0.20 {plus minus} 0.04 mGy. The 40K activity per unit body weight varied inversely with slenderness, and total body K varied directly with body-build index.

  8. (137)Cs, (40)K and (210)Po in marine mammals from the southern Baltic Sea.

    PubMed

    Ciesielski, Tomasz; Góral, Marta; Szefer, Piotr; Jenssen, Bjørn Munro; Bojanowski, Ryszard

    2015-12-15

    This study provides information on baseline concentrations of the radionuclides Cesium-137, Potassium-40 and Polonium-210 in sea mammals from the Baltic Sea. The radionuclides were analyzed in the liver, kidney and muscle of harbor porpoises, striped dolphins, and gray and ringed seals from the Polish coast by γ- and α-spectrometry. Median (137)Cs activities were 14.8, 13.2 and 23.2 Bq kg(-1) w.w. in the liver, kidney and muscles, respectively. Activities of (40)K and (210)Po in the respective tissues were found to be 79.1, 79.8 and 111 Bq kg(-1) for (40)K and 58.1, 59.2 and 32.9 Bq kg(-1) for (210)Po. The measured (137)Cs concentrations were extraordinarily high in comparison to those reported in sea mammals from other locations. However, dose assessments did not imply health effects from (137)Cs exposure in Baltic Sea mammals. Correlations between (137)Cs tissue activities and reported sea water concentrations highlight the potential use of marine mammals for biomonitoring purposes.

  9. The effect of uranium migration on radionuclide distributions for soil samples at the El-Gor area, Sinai, Egypt.

    PubMed

    Nada, A; Aly, H A S

    2014-02-01

    The concentrations and distributions of the activity of natural radionuclides in soil samples were investigated in fifteen soil samples at El-Gor area representing two profiles (A and B) using a HP-Ge detector and alpha counting by SSNTD (CR-39), respectively. The average concentrations of the radionuclides (238)U, (226)Ra, (235)U, (232)Th and (40)K are 203.4, 177.23, 9.77, 43.33 and 386.22 Bq kg(-1) (dry weight), respectively, and profile A and (238)U, (226)Ra, (235)U, (232)Th and (40)K have average concentrations of 232.58, 246, 11.7, 31.7, and 277.07 Bq kg(-1) for profile B, respectively. The eTh and eU were estimated to detect the migration process of uranium into or out of an area or uranium to or from the studied profiles. The results indicate a migration of uranium by 29% for profile A and 65.37% for profile B. The activity ratio ((238)U/(226)Ra) was found to be 0.9 in profile A and 1.15 in profile B. These ratios coincide with the uranium migration processes. The responsible mass corresponding to the measured (226)Ra activity was also calculated. The radon activity concentrations for the two profiles are nearly 300 Bq m(-3). The emanation coefficient (η) was calculated from the ratio of the expected radon activity to the measured radon for the studied soil samples. The value of η was found to depend only on the radium activity regardless to soil formation.

  10. Radiation Doses to Members of the U.S. Population from Ubiquitous Radionuclides in the Body: Part 1, Autopsy and In Vivo Data

    SciTech Connect

    Watson, David J.; Strom, Daniel J.

    2011-02-25

    This paper is part one of a three-part series investigating annual effective doses to residents of the United States from intakes of ubiquitous radionuclides, including radionuclides occurring naturally, radionuclides whose concentrations are technologically enhanced, and anthropogenic radionuclides. This series of papers explicitly excludes intakes from inhaling 222Rn, 220Rn, and their short-lived decay products; it also excludes intakes of radionuclides in occupational and medical settings. The goal of part one of this work was to review, summarize, and characterize all published and some unpublished data for U.S. residents on ubiquitous radionuclide concentrations in tissues and organs. Forty-five papers and reports were obtained and their data reviewed, and three data sets were obtained via private communication. The 45 radionuclides of interest are the 238U series (14 nuclides), the actinium series (headed by 235U; 11 nuclides), and the 232Th series (11 nuclides); primordial radionuclides 87Rb and 40 K; cosmogenic and fallout radionuclides 14C and 3H; and purely anthropogenic radionuclides 137Cs-137mBa, 129I, and 90Sr-90Y. Measurements judged to be relevant were available for only 15 of these radionuclides: 238U, 235U, 234U, 232Th, 230Th, 228Th, 228Ra, 226Ra, 210Pb, 210Po, 137Cs, 87Rb, 40K, 14C, and 3H. Recent and relevant measurements were not available for 129I and 90Sr-90Y. A total of 11,714 radionuclide concentration measurements were found in one or more tissues or organs from 14 States. Data on age, sex, geographic locations, height, and weight of subjects were available only sporadically. Too often authors did not provide meaningful values of uncertainty of measurements so that variability in data sets is confounded with measurement uncertainty. The following papers detail how these shortcomings are overcome to achieve the goals of the three-part series.

  11. Comparative analysis of dose rates in bricks determined by neutron activation analysis, alpha counting and X-ray fluorescence analysis for the thermoluminescence fine grain dating method

    NASA Astrophysics Data System (ADS)

    Bártová, H.; Kučera, J.; Musílek, L.; Trojek, T.

    2014-11-01

    In order to evaluate the age from the equivalent dose and to obtain an optimized and efficient procedure for thermoluminescence (TL) dating, it is necessary to obtain the values of both the internal and the external dose rates from dated samples and from their environment. The measurements described and compared in this paper refer to bricks from historic buildings and a fine-grain dating method. The external doses are therefore negligible, if the samples are taken from a sufficient depth in the wall. However, both the alpha dose rate and the beta and gamma dose rates must be taken into account in the internal dose. The internal dose rate to fine-grain samples is caused by the concentrations of natural radionuclides 238U, 235U, 232Th and members of their decay chains, and by 40K concentrations. Various methods can be used for determining trace concentrations of these natural radionuclides and their contributions to the dose rate. The dose rate fraction from 238U and 232Th can be calculated, e.g., from the alpha count rate, or from the concentrations of 238U and 232Th, measured by neutron activation analysis (NAA). The dose rate fraction from 40K can be calculated from the concentration of potassium measured, e.g., by X-ray fluorescence analysis (XRF) or by NAA. Alpha counting and XRF are relatively simple and are accessible for an ordinary laboratory. NAA can be considered as a more accurate method, but it is more demanding regarding time and costs, since it needs a nuclear reactor as a neutron source. A comparison of these methods allows us to decide whether the time- and cost-saving simpler techniques introduce uncertainty that is still acceptable.

  12. Complete genome sequence of Stackebrandtia nassauensis type strain (LLR-40K-21T)

    SciTech Connect

    Munk, Chris; Lapidus, Alla; Copeland, Alex; Jando, Marlen; Mayilraj, Shanmugam; Glavina Del Rio, Tijana; Nolan, Matt; Chen, Feng; Lucas, Susan; Tice, Hope; Cheng, Jan-Fang; Han, Cliff; Detter, John C.; Bruce, David; Goodwin, Lynne; Chain, Patrick; Pitluck, Sam; Göker, Markus; Ovchinikova, Galina; Pati, Amrita; Ivanova, Natalia; Mavromatis, Konstantinos; Chen, Amy; Palaniappan, Krishna; Land, Miriam; Hauser, Loren; Chang, Yun-Juan; Jeffries, Cynthia D.; Bristow, Jim; Eisen, Jonathan A.; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C.; Klenk, Hans-Peter

    2009-12-30

    Stackebrandtia nassauensis Labeda and Kroppenstedt (2005) is the type species of the genus Stackebrandtia, and a member of the actinobacterial family Glycomycetaceae. Stackebrandtia currently contains two species, which are differentiated from Glycomyces spp. by cellular fatty acid and menaquinone composition. Strain LLR-40K-21T is Gram-positive, aerobic, and nonmotile, with a branched substrate mycelium and on some media an aerial mycelium. The strain was originally isolated from a soil sample collected from a road side in Nassau, Bahamas. We describe the features of this organism, together with the complete genome sequence and annotation. Lastly, this is the first complete genome sequence of the actinobacterial suborder Glycomycineae. The 6,841,557 bp long single replicon genome with its 6487 protein-coding and 53 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.

  13. 40K-40Ca systematics as a Tracer of Silicate Weathering: A Himalayan case study

    NASA Astrophysics Data System (ADS)

    Davenport, Jesse; Caro, Guillaume; France-Lanord, Christian

    2015-04-01

    This study investigates the use of the 40K-40Ca system as a tracer to better quantify the contributions of silicate and carbonate lithologies in the dissolved load of major Himalayan rivers. Previous work using Sr isotopes as a proxy for silicate weathering has been complicated by the redistribution of radiogenic 87Sr between silicate and carbonate lithologies, particularly in the Lesser Himalaya, where dolomites exhibit 87Sr/86Sr ratios as high as 0.85. The 40Ca signature of carbonates, on the other hand, appears to be remarkably resistant to metamorphism and dolomitization [1]. It was therefore anticipated that the 40K-40Ca system could circumvent issues associated with such secondary events, and yield more robust constraints on the relative contribution of silicate vs. carbonate lithologies in dissolved river loads. The main difficulty in applying the 40K-40Ca decay scheme as a tracer lies in the analytical precision required to measure small variations (~1 ɛ-unit) on the large 40Ca isotope (96.9%). This difficulty can now be overcome using the Finnigan Triton TIMS, which allows measurements of the 40Ca/44Ca ratio with external precision of 0.35 ɛ-unit in multidynamic mode. Using this method, we generated high-precision 40Ca data on carbonates/dolomites, bedload sediments, dissolved load, and clay samples originating from and representing the main litho-tectonic units of the Himalaya. Our results show that metamorphosed dolomites from the Lesser Himalaya (LH) exhibit no radiogenic 40Ca excess despite highly variable 87Sr/86Sr signatures (0.73-0.85). Thus, all Himalayan carbonates appear to be characterized by a homogeneous ɛ40Ca=0. In contrast, silicate material is radiogenic, with ɛ40Ca averaging +1 in the Tethyan Sedimentary Series (TSS), +1.6 in the High Himalaya crystalline (HHC) and +4 ɛ-units in the LH. Results obtained from a series of 35 Himalayan rivers (including the Brahmaputra, Ganga and its main tributaries) show that ɛ40Ca in the

  14. Lifetime of 6 Li40 K dimers near a Feshbach resonance

    NASA Astrophysics Data System (ADS)

    Jag, Michael; Cetina, Marko; Lous, Rianne; Levinsen, Jesper; Petrov, Dmitry; Grimm, Rudolf

    2016-05-01

    We investigate the lifetime of bosonic dimers formed in a Fermi- Fermi mixture of 6 Li and 40 K atoms near a Feshbach resonance. Pure dimer samples are created from a Li-K mixture by ramping a magnetic field across the resonance and removing unbound atoms. We then perform lifetime measurements using both trapped high-density as well as expanding low-density samples after release from the trap. These measurements discriminate between the spontaneous and the collisional dimer decay. We further determine the dimer decay due to Li-LiK collisions in an atom-dimer mixture. Our measurements reveal a more than three-fold (five-fold) decrease in decay due to dimer-dimer (atom-dimer) collisions as the Feshbach resonance is approached. This observation is in good agreement with a theoretical prediction, which relates the decay rate to the probability of finding the colliding atoms within a short distance, and can mostly be explained by the increased fermionic character of the halo-dimer state together with Pauli blocking. We apply our model to combinations of other fermionic species to predict the dimer lifetime, which is an important parameter for their prospect towards realizing novel quantum phases. SFB FoQuS.

  15. A thalium-doped sodium iodide well counter for radioactive tracer applications with naturally-abundant 40K

    NASA Astrophysics Data System (ADS)

    Parker, Andrew J.; Boxall, Colin; Joyce, Malcolm J.; Schotanus, Paul

    2013-09-01

    The use of a thallium-doped sodium-iodide well-type scintillation detector for the assay of the low-activity radioisotope 40K, in open-source potassium chloride aqueous solutions, is described. The hazards, safety concerns and radiowaste generation associated with using open-source radioactive isotopes can present significant difficulties, the use of hot cells and escalated costs in radioanalytical laboratory research. A solution to this is the use of low-hazard alternatives that mimic the migration and dispersion characteristics of notable fission products (in this case 137Cs). The use of NaI(Tl) as a detection medium for naturally-abundant levels of 40K in a range of media is widespread, but the use of 40K as a radioactive tracer has not been reported. The use of such low-activity sources is often complicated by the ability to detect them efficiently. In this paper a scintillator detector designed to detect the naturally-abundant 40K present in potassium chloride in tracer applications is described. Examples of the use of potassium chloride as a tracer are given in the context of ion exchange and electrochemical migration studies, and comparisons in performance are drawn from literature with hyper pure germanium semiconductor detectors, which are more commonly utilised detectors in high-resolution counting applications.

  16. Preparation of antifouling polyvinylpyrrolidone (PVP 40K) modified polyethersulfone (PES) ultrafiltration (UF) membrane for water purification

    NASA Astrophysics Data System (ADS)

    Vatsha, Banele; Ngila, Jane Catherine; Moutloali, Richard M.

    This study reports the fabrication of polyethersulfone (PES) membrane using the phase inversion method in the presence of polyvinylpyrrolidone (PVP, 40K) as pore-forming agent. The membranes were made from two PES concentration types, i.e. 16 and 18 wt.%. The effect of high molecular weight PVP concentration (2-10%) was examined in order to obtain a membrane with good performance, i.e. high water flux and reasonable Bovine Serum Albumin (BSA, protein model solution) rejection. The optimised membranes were characterised by ATR-FTIR, AFM, SEM, contact angle and dead-end membrane filtration tests. It was found that PVP moieties have positive influence in the prepared PES membranes. SEM surface and cross-sectional images were used to observed morphological changes as PVP content was varied. The pore sizes increased with PVP content for membranes prepared from 16 wt.% PES polymer, whereas at the higher PVP content in 18 wt.% PES membrane, pore sizes tend to decrease or completely disappear. The CA decreased gradually for the 16 wt.% PES with increasing PVP content whereas in the 18 wt.% PES the CA decreased initially before tapering off or increasing slightly. The rejection of BSA solution by both neat PES and PVP-containing PES membrane was above 85%. AFM surface topography exhibited increase in roughness value with PVP content. FTIR/ATR spectra corroborated the functional composition of neat PES and PVP molecule dispersed on PES membrane backbone. The results attained confirmed the potential industrial application of PVP molecule to minimise fouling tendencies.

  17. Giant Anharmonicity and Theory of Surprising BCS Superconductivity in MgB2 at 40 K

    NASA Astrophysics Data System (ADS)

    Yildirim, Taner

    2002-03-01

    The recent surprise discovery of superconductivity in MgB2 at 40 K has stimulated a great deal of research on this intercalated grahite-like system. Sparked by this discovery, we set out to unlock the structural secrets and, in particular, to reveal the origin of the high Tc in MgB_2; an electron-phonon or other exotic mechanism? To answer this fundamental question, we calculated T_c, its pressure dependence for uni- and biaxial compressions, and the isotope effect from the electronic band structure and lattice dynamics of MgB2 using density functional theory[1-2]. The calculated phonon density of states (DOS) are in excellent agreement with the inelastic neutron scattering measurements. We find that the in-plane boron phonons near the zone-center are very anharmonic and strongly coupled to the planar B sigma bands near the Fermi level. The boron mass and pressure dependence of this mode is found to be the key to quantitatively explaining the observed high T_c, the total isotope effect, and the pressure dependence of T_c. We propose that a stringent test on the hole and phonon based theories of the superconductivity in MgB2 would be a measurement of the biaxial ab-compression dependence of T_c. In collobration with Oguz Gulseren, NIST and UPENN [1] T. Yildirim et. al., Phys. Rev. Lett. 87, 037001 (2001). [2] For details, see http://www.ncnr.nist.gov/staff/taner/mgb2

  18. 40K-40Ca and 87Rb-86Sr Dating by SIMS: The Double-Plus Advantage

    NASA Astrophysics Data System (ADS)

    Harrison, T. M.; McKeegan, K. D.; Schmitt, A. K.

    2009-12-01

    The decay of 40K to 40Ar forms the basis of the potassium-argon dating method, although only one out of every 10 parent atoms decays to daughter 40Ar. The other 90% decay to 40Ca giving, in principle, the 40K-40Ca decay system great potential for dating samples with high K/Ca. This method, however, has not been utilized as an ion-microprobe-based geochronometer, largely because these isotopes require a very high mass resolving power (MRP) of ~25k for full separation. We found that limiting secondary ion transmission in our ims1270 ion microprobe to ~20% permits sufficient separation of 40K from 40Ca (MRP≈ 20k) to permit isotope ratio analysis, albeit with 40Ca+ on the shoulder of the more intense 40K+ peak. A pegmatitic muscovite from Jack Hills (K-Ca age = 2.54 Ga; Fletcher et al., Chem. Geol. 138, 289) yields ~104 cps of both 40K+ and 40Ca+ with a 15 μm primary spot size and O- beam current of 10 nA. The 40Ca+ signal is >90% radiogenic and reflects a “common” Ca content of ≤ 100 ppm. However, application of the relative sensitivity factor (RSF) calculated from the Jack Hills muscovite to unknowns yields relatively high age dispersion, perhaps related to the incompletely separated mass interferences. Theorizing that the noble gas electronic structure of K+ would likely resist further electron loss, we investigated an alternative approach involving analysis of Ca++/K++. The double-plus method provides an important advantage in that K++ species are suppressed by a factor of ~103 relative to K+, thereby effectively removing 40K++ from the spectrum at m/e≈ 20 and leaving 40Ca++ free from any significant interferences at an MRP≈ 4k. Measurement of the much more abundant 39K++ then permits 40Ca++/40K++ to be calculated from the known 39K/40K ratio. We applied this approach to Precambrian muscovite samples obtaining ages similar to, but generally younger than, their associated 40Ar/39Ar ages. This could reflect a minor matrix effect or a lower intrinsic

  19. Analysis of Potassium in Bricks--Determining the Dose Rate from {sup 40}K for Thermoluminescence Dating

    SciTech Connect

    Musilek, Ladislav; Polach, Tomas; Trojek, Tomas

    2008-08-07

    Thermoluminescence (TL) dating is based on accumulating the natural radiation dose in the material of a dated artefact (brick, pottery, etc.), and comparing the dose accumulated during the lifetime of the object with the dose rate within the sample collected for TL measurement. Determining the dose rate from natural radionuclides in materials is one of the most important and most difficult parts of the technique. The most important radionuclides present are usually nuclides of the uranium and thorium decay series and {sup 40}K. An analysis of the total potassium concentration enables us to determine the {sup 40}K content effectively, and from this it is possible to calculate the dose rate originating from this radiation source. X-ray fluorescence (XRF) analysis can be used to determine the potassium concentration in bricks rapidly and efficiently. The procedure for analysing potassium, examples of results of dose rate calculation and possible sources of error are described here.

  20. Neutron scattering studies in the actinide region

    SciTech Connect

    Beghian, L.E.; Kegel, G.H.R.

    1991-08-01

    During the report period we have investigated the following areas: Neutron elastic and inelastic scattering measurements on {sup 14}N, {sup 181}Ta, {sup 232}Th, {sup 238}U and {sup 239}Pu; Prompt fission spectra for {sup 232}Th, {sup 235}U, {sup 238}U and {sup 239}Pu; Theoretical studies of neutron scattering; Neutron filters; New detector systems; and Upgrading of neutron target assembly, data acquisition system, and accelerator/beam-line apparatus.

  1. Neutron scattering studies in the actinide region. Progress report, August 1, 1988--July 31, 1991

    SciTech Connect

    Beghian, L.E.; Kegel, G.H.R.

    1991-08-01

    During the report period we have investigated the following areas: Neutron elastic and inelastic scattering measurements on {sup 14}N, {sup 181}Ta, {sup 232}Th, {sup 238}U and {sup 239}Pu; Prompt fission spectra for {sup 232}Th, {sup 235}U, {sup 238}U and {sup 239}Pu; Theoretical studies of neutron scattering; Neutron filters; New detector systems; and Upgrading of neutron target assembly, data acquisition system, and accelerator/beam-line apparatus.

  2. Estimating adipose tissue in the chest wall using ultrasonic and alternate /sup 40/K and biometric measurements

    SciTech Connect

    Anderson, A.L.; Campbell, G.W.

    1982-01-22

    The percentage of adipose (fat) tissue in the chest wall must be known to accurately measure Pu in the human lung. Correction factors of 100% or more in x-ray detection efficiency are common. Methods using simple /sup 40/K and biometric measurement techniques were investigated to determine the adipose content in the human chest wall. These methods predict adipose content to within 15% of the absolute ultrasonic value. These new methods are discussed and compared with conventional ultrasonic measurement techniques. (ERB)

  3. {sup 40}K, {sup 115}Cs and {sup 226}Ra Soil and Plant Content in Seminatural Grasslands of Central Argentina

    SciTech Connect

    Ayub, J. Juri; Velasco, R. H.; Rizzotto, M.; Quintana, E.; Aguiar, J.

    2008-08-07

    Activity concentrations of {sup 40}K, {sup 226}Ra and {sup 137}Cs have been analyzed in soil and plant samples, collected in permanent grassland in central Argentina. Two near areas (A1 and A2) under field conditions with soil undisturbed at least in the last four decades were selected. For each of the three studied radionuclides we do not find differences in the inventories between both areas. The inventories range from 143 kBq m{sup -2} to 197 kBq m{sup -2} for {sup 40}K and from 13 kBq m{sup -2} to 18 kBq m{sup -2} for {sup 226}Ra. The vertical distributions of {sup 40}K and {sup 226}Ra are uniform through de soil profile. For {sup 137}Cs the inventories range from 0.33 kBq m{sup -2} to 0.73 kBq m{sup -2}. In spite of {sup 137}Cs inventories are similar in both areas the distribution through vertical profile is different. {sup 137}Cs activity concentration has a maximum for layers 5-10 cm depth in A1 and 10-15 cm depth in A2. For deeper layers both areas show similar activity concentrations. The diffusion coefficient (D{sub s}) and convection velocity (v{sub s}) are estimated with a convection-diffusion model. D{sub s} values are in the range reported in the bibliography, while v{sub s} values are one order of magnitude higher. After 40 years most {sup 137}Cs fallout is still in the layer 10-15 cm depth. The great penetration of {sup 137}Cs (25 cm) in these soils may be the result of a high sand and low fine materials content. {sup 137}Cs and {sup 226}Ra were not detected in grass samples. Activity concentration of {sup 40}K in vegetal samples ranges from 116 Bq kg{sup -1} to 613 Bq kg{sup -1}. The TF values obtained for {sup 40}K show a lognormal distribution and ranges from 0.05 to 0.42.

  4. Determination of potassium in several plants and study of potassium transfer to different beverages, including tequila, by measurement of 40K

    NASA Astrophysics Data System (ADS)

    Navarrete, J. M.; Muller, G.; Cabrera, L.; Martinez, T.

    2006-01-01

    Measurement of 40K was used for determination of potassium concentrations in leaves of agave and maguey cactus leaves, and coffee beans of various origins. The procedure was also used to study potassium transfer to tequila (alcoholic drink made of agave cactus), and the cactus and coffee infusions using 40K as a natural radioactive tracer. Counting of 40K in Marinelli containers with the aid of a low background NaI(Ti) scintillation detection system for 12 24 hours was employed. The method appeared to be simple and suitable for determination of potassium concentrations in large samples, which eliminates homogeneity problems.

  5. Evaluation of the activity concentrations of (137) Cs and (40)K in some Chanterelle mushrooms from Poland and China.

    PubMed

    Falandysz, Jerzy; Zalewska, Tamara; Apanel, Anna; Drewnowska, Małgorzata; Kluza, Karolina

    2016-10-01

    The activity concentrations of (137)Cs and (40)K in mushrooms of the genus Cantharellus (Cantharellus cibarius, Cantharellus tubaeformis, and Cantharellus minor) collected across Poland from 1997 to 2013 and in Yunnan province of China in 2013 were determined using gamma spectrometry with an HPGe detector, respectively. Activity concentrations of (137)Cs in C. cibarius from the places in Poland varied from 64 ± 3 to 1600 ± 47 Bq kg(-1) db in 1997-2004 and 4.2 ± 1.2 to 1400 ± 15 Bq kg(-1) db in 2006-2013. In the Chinese Cantharellus mushrooms, the activity level of (137)Cs was very low, i.e., at a range <1.2 to 1.2 ± 0.6 Bq kg(-1) dry biomass. The natural radionuclide (40)K was at similar activity level in C. cibarius collected across Poland and in China, and fluctuations in levels of (40)K over the years and locations in Poland were small. In C. cibarius from diverse sites in Poland, content of (137)Cs highly fluctuated in 1998-2013 but no clear downward trend was visible (Fig. 1). Published activity levels of (137)Cs in fruitbodies of Cantharellus such Cantharellus californicus, Cantharellus cascadensis, C. cibarius, Cantharellus cinnabarius, Cantharellus formosus, Cantharellus iuteocomus, Cantharellus lutescens, Cantharellus minor, Cantharellus pallens [current name C. cibarius], Cantharellus subalbidus, Cantharellus subpruinosus, and C. tubaeformis collected worldwide were compared. In the Polish cuisine, mushrooms of the genus Cantharellus are blanched before frying or pickling, and this kind of treatment, and additionally also pickling, both very efficiently remove alkali elements (and radioactivity from (134/137)Cs) from flesh of the species. PMID:27438876

  6. Anthropogenic and geogenic radionuclides content in an undisturbed Slovenian forest soil

    NASA Astrophysics Data System (ADS)

    P, Jankong; L, Mabit; A, Toloza; v, Zupanc

    2010-05-01

    The measurements of natural background radiation and anthropogenic radionuclides in terrestrial environment, especially in soil, have been carried out in many countries for several decades to establish base line data of radiation level. So far, the knowledge of radionuclides concentration levels in Slovenia is limited to a few investigations and the use of anthropogenic 137Cs radionuclide has not yet been used as soil landscape tracer in Slovenia. Therefore, the purposes of this study were: (i) to collect the inventory information of naturally occurring isotope (40K, 226Ra, 232Th, 235U and 238U) and man-made radionuclides (137Cs) as well as their depth/vertical distribution in soil; (ii) to complete radio-ecological survey information in Slovenia and provide information regarding the external dose-rate based on the depth distributions of the gamma emitters in the soil of the study area; and (iii) to establish a reference inventory value of 137Cs fallout in order to prepare for a future investigation to test 137Cs as soil tracer under Slovenian agro-environment. To estimate the natural level of radioactivity and the initial fallout of 137Cs, twenty soil profiles (0-40cm) divided into four increments of 10 cm were collected in an undisturbed forest located in East Slovenia in Šalamenci close to the Hungarian and Austrian borders at the beginning of the Pannonian plains. Depending on the depth increment, the average activity concentration of 137Cs, 40K, 226Ra, 232Th, 235U and 238U were found to be respectively from 0.47 ± 0.27 to 70 ± 33 Bq kg-1, from 535 ± 16 to 703 ± 20 Bq kg-1, from 51 ± 3 to 49 ± 2 Bq kg-1, from 54 ± 6 to 62 ± 4 Bq kg-1, from 7.8 ± 0.8 to 8.1 ± 0.3 Bq kg-1and from 58 ± 22 to 68 ± 27 Bq kg-1. On average the top soil mass activity of 40K is 7 to 8 times higher than that of 137Cs and the depth distribution of this isotope, instead of showing a constant amount along the soil profile, presents an increase with depth. The external gamma

  7. Study on vertical distribution of radionuclides (40K, Th and U) in soil collected from Manjung district

    NASA Astrophysics Data System (ADS)

    Zainal, Fetri; Hamzah, Zaini; Saat, Ahmad; Wood, Khalik; Alias, Masitah

    2016-01-01

    The accumulation of radionuclides in soil is a greatest concerns due to their toxicity. This study investigated the vertical distribution of radionuclides and radiological assessment in a soil profile were collected in three different directions [North (N), North-East (NE) and South-East (SE)] within 40 km from Manjung district. All profile samples were collected down to 45cm at 7.5cm interval using hand auger. Soil density and radionuclides (40K, Th and U) concentrations were determined by gravimetric method and Energy Dispersive X-Ray Fluorescence (EDXRF) technique, respectively. The radionuclides concentrations was in decreasing order of 40K > Th > U. Soil quality assessment was carried out using Enrichment Factor (EF), Pollution Index (PI) and Geoaccumulation Index (I geo) where all radionuclides show significant enrichment (5 < EF < 20), PI classified as middle pollution classes and 0 < Igeo < 1, indicating moderately polluted, respectively. From the concentration of radionuclides, the radiological risk was calculated and the present result show external hazard index (Hex) is below than unity indicate low radiological risk.

  8. Purification and functional analysis of a 40 kD protein extracted from the Strombus decorus persicus mollusk shells.

    PubMed

    Pokroy, Boaz; Zolotoyabko, Emil; Adir, Noam

    2006-02-01

    A 40 kD protein has been extracted from the biomineral matrix of the calcium carbonate gastropod shell of Strombus decorus persicus. The protein was isolated by decalcification and ion exchange HPLC. We have named this protein ACLS40, i.e., aragonite crossed-lamellar structure protein. A partial sequence of the isolated ACLS40 and amino acid analysis both indicate that it does not belong to the family of very acidic proteins, i.e., rich in aspartic and glutamic residues. The shell-extracted protein shows the ability to stabilize calcium carbonate in vitro, in the form of thermodynamically unstable vaterite polymorph, and to inhibit the growth of calcite. PMID:16471929

  9. Qualification of a 40 kA Nb{sub 3}Sn superconducting conductor for NET/ITER coils

    SciTech Connect

    Bessette, D.; Duchateau, J.L.; Decool, P.; Turck, B.; Blau, B.

    1994-07-01

    A 40 kA Nb{sub 3}Sn conductor, designed to operate with forced helium flow at 4.5 K was tested in the SULTAN III facility, (I{sub max} = 50kA, B{sub max} (background) = 11T). The test sample and the operating conditions of the test facility are described. Two measurement procedures were used to investigate the conductor behavior near the critical value: sample current or temperature are increased up to the quench with background field and temperature or current reciprocally kept at steady state. The critical current of the conductor could be measured with the same criterion as for the basic strand (0.1 {mu}V/cm). The obtained results are discussed and compared with the basic strand performances. In addition some results on the thermohydraulic behavior of the CIC conductor are presented.

  10. Distribution of natural and artificial radionuclides in chernozem soil/crop system from stationary experiments.

    PubMed

    Sarap, Nataša B; Rajačić, Milica M; Đalović, Ivica G; Šeremešić, Srđan I; Đorđević, Aleksandar R; Janković, Marija M; Daković, Marko Z

    2016-09-01

    The present paper focuses on the determination of radiological characteristics of cultivated chernozem soil and crops from long-term field experiments, taking into account the importance of distribution and transfer of radionuclides in the soil-plant system, especially in agricultural cropland. The investigation was performed on the experimental fields where maize, winter wheat, and rapeseed were cultivated. Analysis of radioactivity included determination of the gross alpha and beta activity as a screening method, as well as the activities of the following radionuclides: natural ((210)Pb, (235)U, (238)U, (226)Ra, (232)Th, (40)K, (7)Be) and artificial ((90)Sr and (137)Cs). The activities of natural and artificial ((137)Cs) radionuclides were determined by gamma spectrometry, while the artificial radionuclide (90)Sr was determined by a radiochemical analytical method. Based on the obtained results for the specific activity of (40)K, (137)Cs, and (90)Sr, accumulation factors for these radionuclides were calculated in order to estimate transfer of radionuclides from soil to crops. The results of performed analyses showed that there is no increase of radioactivity that could endanger the food production through the grown crops. PMID:27250084

  11. Breeding of {sup 233}U in the thorium–uranium fuel cycle in VVER reactors using heavy water

    SciTech Connect

    Marshalkin, V. E. Povyshev, V. M.

    2015-12-15

    A method is proposed for achieving optimal neutron kinetics and efficient isotope transmutation in the {sup 233}U–{sup 232}Th oxide fuel of water-moderated reactors with variable water composition (D{sub 2}O, H{sub 2}O) that ensures breeding of the {sup 233}U and {sup 235}U isotopes. The method is comparatively simple to implement.

  12. Breeding of 233U in the thorium-uranium fuel cycle in VVER reactors using heavy water

    NASA Astrophysics Data System (ADS)

    Marshalkin, V. E.; Povyshev, V. M.

    2015-12-01

    A method is proposed for achieving optimal neutron kinetics and efficient isotope transmutation in the 233U-232Th oxide fuel of water-moderated reactors with variable water composition (D2O, H2O) that ensures breeding of the 233U and 235U isotopes. The method is comparatively simple to implement.

  13. Sequence of the human 40-kDa keratin reveals an unusual structure with very high sequence identity to the corresponding bovine keratin.

    PubMed Central

    Eckert, R L

    1988-01-01

    The complete amino acid and DNA sequences of the human 40-kDa keratin are reported. The DNA sequence encodes a protein of 44,098 Da, which is unique in that it lacks the terminal non-alpha-helical tail segment found in all other keratins. When the human 40-kDa keratin amino acid sequence is compared to the corresponding bovine keratin, the overall identity is 89%. The coil-forming regions are 89% identical and the head regions are 88% identical. This similarity is also evident in the DNA sequence of the coding region, the 5' upstream sequences, and the 3' noncoding sequences. The high degree of cross-species identity between bovine and human 40-kDa keratins suggests that there is strong evolutionary pressure to conserve the structure of this keratin. This in turn suggests an important and universal role for this intermediate filament subunit in all species. Images PMID:2448790

  14. Radiation doses to members of the U.S. population from ubiquitous radionuclides in the body: Part 1, autopsy and in vivo data.

    PubMed

    Watson, David J; Strom, Daniel J

    2011-04-01

    This paper is Part 1 of a three-part series investigating steady-state effective dose rates to residents of the United States from intakes of ubiquitous radionuclides, including radionuclides occurring naturally, radionuclides whose concentrations are technologically enhanced, and anthropogenic radionuclides. This series of papers explicitly excludes intakes from inhaling (222)Rn, (220)Rn, and their short-lived decay products; it also excludes intakes of radionuclides in occupational and medical settings. In this work, it is assumed that instantaneous dose rates in target organs are proportional to steady-state radionuclide concentrations in source regions. The goal of Part 1 of this work was to review, summarize, and characterize all published and some unpublished data for U.S. residents on ubiquitous radionuclide concentrations in tissues and organs. Forty-five papers and reports were obtained and their data reviewed, and three data sets were obtained via private communication. The 45 radionuclides of interest are the (238)U series (14 nuclides), the actinium series (headed by (235)U; 11 nuclides), and the (232)Th series (11 nuclides); primordial radionuclides (87)Rb and (40)K; cosmogenic and fallout radionuclides (14)C and (3)H; and purely anthropogenic radionuclides (137)Cs-(137m)Ba, (129)I, and (90)Sr-(90)Y. Measurements judged to be relevant were available for only 15 of these radionuclides: (238)U, (235)U, (234)U, (232)Th, (230)Th, (228)Th, (228)Ra, (226)Ra, (210)Pb, (210)Po, (137)Cs, (87)Rb, (40)K, (14)C, and (3)H. Recent and relevant measurements were not available for (129)I and (90)Sr-(90)Y. A total of 11,741 radionuclide concentration measurements were found in one or more tissues or organs from 14 states. Data on age, gender, geographic locations, height, and weight of subjects were available only sporadically. Too often authors did not provide meaningful values of uncertainty of measurements, so that variability in data sets is confounded with

  15. Radiation doses to members of the U.S. population from ubiquitous radionuclides in the body: Part 1, autopsy and in vivo data.

    PubMed

    Watson, David J; Strom, Daniel J

    2011-04-01

    This paper is Part 1 of a three-part series investigating steady-state effective dose rates to residents of the United States from intakes of ubiquitous radionuclides, including radionuclides occurring naturally, radionuclides whose concentrations are technologically enhanced, and anthropogenic radionuclides. This series of papers explicitly excludes intakes from inhaling (222)Rn, (220)Rn, and their short-lived decay products; it also excludes intakes of radionuclides in occupational and medical settings. In this work, it is assumed that instantaneous dose rates in target organs are proportional to steady-state radionuclide concentrations in source regions. The goal of Part 1 of this work was to review, summarize, and characterize all published and some unpublished data for U.S. residents on ubiquitous radionuclide concentrations in tissues and organs. Forty-five papers and reports were obtained and their data reviewed, and three data sets were obtained via private communication. The 45 radionuclides of interest are the (238)U series (14 nuclides), the actinium series (headed by (235)U; 11 nuclides), and the (232)Th series (11 nuclides); primordial radionuclides (87)Rb and (40)K; cosmogenic and fallout radionuclides (14)C and (3)H; and purely anthropogenic radionuclides (137)Cs-(137m)Ba, (129)I, and (90)Sr-(90)Y. Measurements judged to be relevant were available for only 15 of these radionuclides: (238)U, (235)U, (234)U, (232)Th, (230)Th, (228)Th, (228)Ra, (226)Ra, (210)Pb, (210)Po, (137)Cs, (87)Rb, (40)K, (14)C, and (3)H. Recent and relevant measurements were not available for (129)I and (90)Sr-(90)Y. A total of 11,741 radionuclide concentration measurements were found in one or more tissues or organs from 14 states. Data on age, gender, geographic locations, height, and weight of subjects were available only sporadically. Too often authors did not provide meaningful values of uncertainty of measurements, so that variability in data sets is confounded with

  16. Acoustic particle manipulation in a 40 kHz quarter-wavelength standing wave with an air boundary.

    PubMed

    Trippa, Giuliana; Trine, Stéphanie; Ventikos, Yiannis; Coussios, Constantin-C

    2012-05-01

    An implementation of a quarter-wavelength standing wave separator that exploits an air drum to achieve the pressure node is presented and characterized experimentally. The air drum configuration was implemented and tested in a set-up with a 40 kHz transducer immersed in a water tank with the quarter-wavelength gap being approximately 9 mm wide. Injection of suspensions of 5 μm and 45 μm diameter polystyrene particles at flow rates of 30 ml/h and 60 ml/h was studied and particle deflection towards the pressure node at the air drum surface was observed for a range of acoustic pressures. Computational results on single particle trajectories show good agreement with the experimental findings for the 45 μm particles, but not for the 5 μm particles. These were considered to behave as aggregates of higher effective dimension, due to their much higher number density relative to the 45 μm particles in the suspensions used. The set-up developed in this study includes a robust method for achieving a pressure node in a quarter-wavelength system and can represent the first step toward the development of an alternative separator configuration in respect to small channel MHz range operated systems for the manipulation of particles streams.

  17. 137Cs and 40K in the terrestrial vegetation of the Yenisey Estuary: landscape, soil and plant relationships.

    PubMed

    Korobova, Elena M; Brown, Justin B; Ukraintseva, Natalia G; Surkov, Vitaly V

    2007-01-01

    Plant species, forming important components of Arctic food chains and of interest from a monitoring perspective, were studied at 36 plots representing flood plain and terrace landscapes of the Yenisey River and Estuary from its upper delta to the gulf. (137)Cs contamination densities at the plots varied from 0.35kBq/m(2) (central delta, sandy riverside plot) to 88kBq/m(2) (the upper delta plot) indicating both global and regional sources of anthropogenic pollution. Cs-137 levels in plants were within the range expected from global fallout inputs and varied from 31 to 140Bq/kg d.w. increasing in dominant groups in the order: grasses40)K content and lower (137)Cs Tag compared to mosses and alder, respectively. This makes the latter plant types more appropriate indicators of (137)Cs contamination.

  18. The preliminary results of the measurements of environmental levels of 40K and 137Cs in Venezuela

    NASA Astrophysics Data System (ADS)

    LaBrecque, J. J.; Rosales, P. A.; Carias, O.

    1992-02-01

    The study of the beta-particle radioactivity in air and 90Sr in rainwater collected at Instituto Venezolano de Investigaciones Cientificas, IVIC, that began in 1959 in conjunction with the U.S. Atomic Energy Commission was discontinued in 1963. But after the Chernobyl nuclear power plant accident in the USSR, work on the radioactive contamination in Venezuela has been renewed. Initially the measurement of 134Cs and 137Cs in imported foodstuffs, such as milk powders and meats were undertaken, and these have now been extended to measurements of environmental levels of 40K and 137Cs in soils, sea sediments and foodstuffs. The data present herein are the only readily available data on radioactive contamination in the environment in Venezuela since 1963. The measurements were performed with a simple Nal(Tl) detector and two single channel analyzers as well as with a 25% efficient hyper-pure germanium semiconductor coupled to a multichannel analyzer system. Finally, these results can be used as baseline values (environmental background) in case of a nuclear accident in the region, as well as to screen imported foodstuff which is suspected to be contaminated.

  19. 210Po, 210Pb, 40K and 137Cs in edible wild berries and mushrooms and ingestion doses to man from high consumption rates of these wild foods.

    PubMed

    Gwynn, Justin P; Nalbandyan, Anna; Rudolfsen, Geir

    2013-02-01

    This paper discusses activity concentrations of (210)Po, (210)Pb, (40)K and (137)Cs in edible wild berries and mushrooms collected from Øvre Dividalen national park, Northern Norway and derives committed effective ingestion doses to man based on high consumption rates of these wild foods. Edible wild berries and mushrooms accumulated similar levels of (210)Pb, but mushrooms accumulated higher levels of (210)Po and (40)K than berries. There appears to be a clear difference in the ability of Leccinum spp. of fungi to accumulate (210)Po and/or translocate (210)Po to mushrooms compared to Russula spp. of fungi. Activity concentrations of (137)Cs in edible wild berries and mushrooms from Øvre Dividalen national park reflected the lower levels of fallout of this radionuclide in Northern Norway compared to more central areas following the Chernobyl accident. For mushrooms, ingestion doses are dominated by (210)Po, while for berries, (40)K is typically the main contributor to dose. Based on high consumption rates, ingestion doses arising from the combination of (210)Po, (210)Pb and (40)K were up to 0.05 mSv/a for berries and 0.50 mSv/a for mushrooms. Consumption of such wild foods may result in a significant contribution to total annual doses when consumed in large quantities, particularly when selecting mushrooms species that accumulate high activity concentrations of (210)Po.

  20. Behavior of ambient concentrations of natural radionuclides (7)Be, (210)Pb, (40)K in the Mediterranean coastal city of Málaga (Spain).

    PubMed

    Gordo, E; Dueñas, C; Fernández, M C; Liger, E; Cañete, S

    2015-05-01

    During a 4-year period (January 2009-December 2012), the (7)Be, (210)Pb, and (40)K activity concentrations in airborne particulate matter were weekly determined at the Málaga (Spain) located in the southern Iberian Peninsula. Totally 209 polypropylene filters were analyzed in the mentioned period. In 100% of the filters, (7)Be and (40)K activity concentrations were detected while (210)Pb activity concentration was detected in 96% of the filters. The results from individual measurements of (7)Be, (210)Pb, and (40)K concentrations were analyzed to derive the statistical estimates characterizing the distributions. Principal components analysis (PCA) was applied to the datasets and the results of the study reveal that aerosol behavior is represented by two principal components which explain 73.2% of total variance. Components PC1 and PC2 respectively explain 46.0 and 27.2% of total variance. PC1 was related positively to dust content, (7)Be and (40)K concentrations and negatively to sunspot numbers. In contrast, PC2 was related positively to temperature and (210)Pb activity and negatively to precipitation and relative humidity. The (7)Be levels showed a significant correlation with sunspot numbers due to the cosmogenic origin. (40)K activities showed a good correlation with dust deposition in filters mainly because it was transported to the air as resuspended particle from the soil. An inverse relationship was observed between the (210)Pb concentrations and monthly rainfall, indicating washout of atmospheric aerosols carrying these radionuclides and a pronounced positive correlation with the average monthly temperature of air.

  1. Natural radioactivity content of granite tiles used in Greece.

    PubMed

    Papaefthymiou, H

    2008-01-01

    Measurements of (226)Ra, (232)Th and (40)K activity concentrations in commercial granite tiles imported in Greece were performed using gamma-ray spectrometry. The activity concentration of (226)Ra, (232)Th and (40)K ranged from 1 to 434, 2 to 239 and 71 to 1576 Bq kg(-1), respectively. The calculated activity concentration index (I) values for all granite samples examined were found to be within the EC limit values for superficial and other materials with restricted use.

  2. Cocaine treatment increases expression of a 40 kDa catecholamine-regulated protein in discrete brain regions.

    PubMed

    Sharan, Niki; Chong, Victor Z; Nair, Venugopalan D; Mishra, Ram K; Hayes, Robert J; Gardner, Eliot L

    2003-01-01

    Previous reports from our laboratory have described brain-specific catecholamine-regulated proteins, which bind dopamine and related catecholamines. Evidence from the molecular cloning of a 40 kDa catecholamine-regulated protein (CRP40) revealed that CRP40 is dopamine-inducible and has properties similar to those of the 70 kDa heat shock protein (HSP70) family. The present study investigates the effects of acute and chronic cocaine treatment on CRP40 expression in the striatum, nucleus accumbens, prefrontal cortex, and medulla. Acute treatment with cocaine increased CRP40 expression in the nucleus accumbens and striatum, whereas chronic treatment with cocaine increased CRP40 expression in the nucleus accumbens only. Neither of these treatments affected CRP40 levels in the prefrontal cortex or medulla. In addition, pretreatment with the spin-trapping agent alpha-phenyl-tert-butylnitrone did not attenuate cocaine-induced expression of CRP40, suggesting that the observed increases in CRP40 levels were not caused by free radicals. On the other hand, pretreatment with anisomycin, a protein synthesis inhibitor, blocked the cocaine-induced expression of CRP40. Thus, protein synthesis may be involved in the observed CRP40 level increases. Furthermore, neither acute nor chronic cocaine treatment affected levels of inducible or constitutively expressed HSP70, which indicates a specificity of cocaine's effects on CRP40. Since cocaine has been shown to increase extracellular dopamine levels, these findings suggest that increased expression of CRP40 is associated with high extracellular levels of dopamine (or its metabolites). Elevated levels of CRP40 could play a protective role for dopamine neurons in response to increased oxidative stress that has been shown to be induced by cocaine and that can lead to apoptosis and neurodegeneration. PMID:12422371

  3. Resonance integral calculations for isolated rods containing oxides of /sup 238/U and /sup 232/Th

    SciTech Connect

    Baker, V.C.; Marable, J.H.

    1980-02-01

    Results of resonance integral calculations for UO/sub 2/ and ThO/sub 2/ isolated rods are discussed. The calculations were performed with ENDF/B-IV cross-section data and the multigroup transport code ANISN. The findings reported demonstrate by comparison with semiempirical relationships (based on experimentally derived results) the suitability of the method used for determining resonance integrals. The calculations were based on a cylindrical rod in an H/sub 2/O moderator of large radius. Multigroup cross sections were obtained by a MINX-SPHINX-AMMPX sequence, and ANISN was used to account for the neutron flux and capture rates. A special approach was used to determine a neutron source distribution such that the flux in the moderator region was forced to behave in an asymptotic way; thus, the ideal resonance integral experiment could be calculated. The UO/sub 2/ resonance integrals calculated were in exceptionally good agreement with experimental values based on isolated rods. The ThO/sub 2/ results were approximately 6% lower than experimental values, and efforts to understand the discrepancy are discussed. 8 figures, 7 tables.

  4. Novel chiral three-dimensional iron(III) compound exhibiting magnetic ordering at T(c) = 40 K.

    PubMed

    Armentano, Donatella; De Munno, Giovanni; Lloret, Francesc; Palii, Andrei V; Julve, Miguel

    2002-04-22

    The preparation and crystal structure determination of the iron(III) compound of formula [(NH(4))(2)[Fe(2)O(ox)(2)Cl(2)].2H(2)O](n) (1) (ox = oxalate dianion) are reported here. Complex 1 crystallizes in the orthorhombic system, space group Fdd2, with a = 14.956(7) A, b = 23.671(9) A, c = 9.026(4) A, and Z = 8. The structure of complex 1 consists of the chiral anionic three-dimensional network [Fe(2)O(ox)(2)Cl(2)](2-) where the iron(III) ions are connected by single oxo and bisbidentate oxalato groups. The metal-metal separations through these bridging ligands are 3.384(2) and 5.496(2) A, respectively. Ammonium cations and crystallization water molecules are located in the helical pseudohexagonal tunnels defined by iron atoms. The longest iron-iron distance in the pseudohexagonal tunnel is 15.778(2) A whereas the shortest one is 8.734(2) A. The iron atoms are hexacoordinated: a terminal chloro ligand and five oxygen atoms, that of the oxo group and four from two cis coordinated oxalate ligands, build a distorted octahedral environment around the metal atom. The Fe-O(oxo) bond distance [1.825(2) A] is significantly shorter than the Fe(III)-O(ox) [average value 2.103(4) A] and Fe(III)-Cl bond distances [2.314(2) A]. Magnetic susceptibility measurements of 1 in the temperature range 2.0-300 K reveal the occurrence of a susceptibility maximum at 195 K and a transition toward a magnetically ordered state in the lower temperature region with T(c) = 40 K. The strong antiferromagnetic coupling through the oxo bridge (J = -46.4 cm(-1), the Hamiltonian being H = -JS(A).S(B)) accounts for the susceptibility maximum whereas a weak spin canting of approximately 0.3 degrees due to the antisymmetric magnetic exchange within the chiral three-dimensional network is responsible for the magnetic ordering. The values of coercive field (H(c)) and remnant magnetization (M(r)) obtained from the hysteresis loop of 1 at 5 K are 4000 G and 0.016 micro(B).

  5. Measurement of (238)U, (228)Ra, (226)Ra, (40)K and (137)Cs in foodstuffs samples collected from coastal areas of China.

    PubMed

    Tuo, Fei; Zhang, Qing; Zhou, Qiang; Xu, Cuihua; Zhang, Jing; Li, Wenhong; Zhang, Jianfeng; Su, Xu

    2016-05-01

    This study represents a total of 245 samples collected. The activities of (238)U, (228)Ra, (226)Ra, (40)K and (137)Cs were determined in samples of vegetables, tea, cereal (rice, wheat and corn), meat, poultry, freshwater product, seafood and seaweed that collected from the 30km safety zone of the Nuclear Power Plants (NPPs) area. All the samples radionuclide activities were quantified by using High Purity Germanium (HPGe) gamma spectrometry. The geometric mean concentrations (Bqkg(-1) wet weight) for (238)U, (228)Ra, (226)Ra, (40)K, and (137)Cs in all investigated foodstuffs samples, are 0.13, 0.16, 0.11, 68 and 0.02, respectively. The arithmetic mean concentrations (Bqkg(-1) wet weight) for (238)U, (228)Ra, (226)Ra, (40)K, and (137)Cs in all investigated foodstuffs samples, are 0.34, 0.65, 0.32, 111 and 0.09, respectively. Results of this study were compared with others, the measured values are the same with those of a previous investigation. Radiation doses due to the consumption of these foodstuffs to humans are estimated to comprise around 37-46% of the annual dose limit for public.

  6. Concentrations of {sup 137}Cs and {sup 40}K in edible mushrooms collected in Japan and radiation dose due to their consumption

    SciTech Connect

    Ban-nai, Tadaaki; Muramatsu, Yasuyuki; Yoshida, Satoshi

    1997-03-01

    To estimate radiocesium intake due to eating mushrooms, about 100 samples belonging to 11 species were analyzed to establish to establish representative values for {sup 137}Cs and {sup 40}K in common edible mushrooms available in food markets. Concentration ranges were <0.047-39 Bq kg{sup -1} (wet wt) for {sup 137}Cs and 30-210 Bq kg{sup -1} (wet wt) for {sup 40}K. The median concentrations were 1.3 Bq kg{sup -1} (wet wt) for {sup 137}Cs and 97 Bq kg{sup -1} (wet wt) for {sup 40}K. The {sup 137}Cs concentration is cultivated mushrooms were markedly lower than those in wild mushrooms. The annual intake of {sup 137}Cs per person through mushrooms was calculated (using analytical results and food consumption data in Japan) to be 6.0 Bq for {sup 137}Cs, which is about 32% of the total dietary intake of this nuclide. The effective dose equivalent of {sup 137}Cs through mushroom was estimated to be 7.7 X 10{sup -8} Sv (range estimated from the standard deviation: 3.0 x 10{sup -8}-1.0 x 10{sup -7}). 19 refs., 1 fig., 2 tabs.

  7. 40-kDa protein from thin filaments of the mussel Crenomytilus grayanus changes the conformation of F-actin during the ATPase cycle.

    PubMed

    Sirenko, V V; Simonyan, A H; Dobrzhanskaya, A V; Shelud'ko, N S; Borovikov, Y S

    2013-03-01

    Polarized fluorimetry was used to study in ghost muscle fibers the influence of a 40-kDa protein from the thin filaments of the mussel Crenomytilus grayanus on conformational changes of F-actin modified by the fluorescent probes 1,5-IAEDANS and FITC-phalloidin during myosin subfragment (S1) binding in the absence of nucleotides and in the presence of MgADP or MgATP. The fluorescence probes were rigidly bound with actin, which made the absorption and emission dipoles of the probes sensitive to changes in the orientation and mobility of both actin monomer and its subdomain-1 in thin filaments of the muscle fiber. On modeling different intermediate states of actomyosin, the orientation and mobility of oscillators of the dyes were changed discretely, which suggests multistep changes in the actin conformation during the cycle of ATP hydrolysis. The 40-kDa protein influenced the orientation and mobility of the fluorescent probes markedly, suppressing changes in their orientation and mobility in the absence of nucleotides and in the presence of MgADP, but enhancing these changes in the presence of MgATP. The calponin-like 40-kDa protein is supposed to prevent formation of the strong binding state of actomyosin in the absence of nucleotides and in the presence of MgADP but to activate formation of this state in the presence of MgATP.

  8. Measurement of (238)U, (228)Ra, (226)Ra, (40)K and (137)Cs in foodstuffs samples collected from coastal areas of China.

    PubMed

    Tuo, Fei; Zhang, Qing; Zhou, Qiang; Xu, Cuihua; Zhang, Jing; Li, Wenhong; Zhang, Jianfeng; Su, Xu

    2016-05-01

    This study represents a total of 245 samples collected. The activities of (238)U, (228)Ra, (226)Ra, (40)K and (137)Cs were determined in samples of vegetables, tea, cereal (rice, wheat and corn), meat, poultry, freshwater product, seafood and seaweed that collected from the 30km safety zone of the Nuclear Power Plants (NPPs) area. All the samples radionuclide activities were quantified by using High Purity Germanium (HPGe) gamma spectrometry. The geometric mean concentrations (Bqkg(-1) wet weight) for (238)U, (228)Ra, (226)Ra, (40)K, and (137)Cs in all investigated foodstuffs samples, are 0.13, 0.16, 0.11, 68 and 0.02, respectively. The arithmetic mean concentrations (Bqkg(-1) wet weight) for (238)U, (228)Ra, (226)Ra, (40)K, and (137)Cs in all investigated foodstuffs samples, are 0.34, 0.65, 0.32, 111 and 0.09, respectively. Results of this study were compared with others, the measured values are the same with those of a previous investigation. Radiation doses due to the consumption of these foodstuffs to humans are estimated to comprise around 37-46% of the annual dose limit for public. PMID:26926376

  9. Age and Duration of Weathering by 40K-40Ar and 40Ar/39Ar Analysis of Potassium-Manganese Oxides.

    PubMed

    Vasconcelos, P M; Becker, T A; Renne, P R; Brimhall, G H

    1992-10-16

    Supergene cryptomelane [K(1-2)(Mn(3+)Mn(4+))(8)O(16). chiH(2)O] samples from deeply weathered pegmatites in southeastern Brazil subjected to (40)K-(40)Ar and (40)Ar/(39)Ar analysis yielded (40)K-(40)Ar dates ranging from 10.1 +/- 0.5 to 5.6 +/- 0.2 Ma (million years ago). Laser-probe (40)Ar/(39)Ar step-heating of the two most disparate samples yielded plateau dates of 9.94 +/- 0.05 and 5.59 +/- 0.10 Ma, corresponding, within 2 sigma, to the (40)K-(40)Ar dates. The results imply that deep weathering profiles along the eastern Brazilian margin do not reflect present climatic conditions but are the result of a long-term process that was already advanced by the late Miocene. Weathering ages predate pulses of continental sedimentation along the eastern Brazilian margin and suggest that there was a time lag between weathering and erosion processes and sedimentation processes.

  10. Rare earth elements in fly ashes created during the coal burning process in certain coal-fired power plants operating in Poland - Upper Silesian Industrial Region.

    PubMed

    Smolka-Danielowska, Danuta

    2010-11-01

    The subject of the study covered volatile ashes created during hard coal burning process in ash furnaces, in power plants operating in the Upper Silesian Industrial Region, Southern Poland. Coal-fired power plants are furnished with dust extracting devices, electro precipitators, with 99-99.6% combustion gas extracting efficiency. Activity concentrations ofTh-232, Ra-226, K-40, Ac-228, U-235 and U-238 were measured with gamma-ray spectrometer. Concentrations of selected rare soil elements (La, Ce, Nd, Sm, Y, Gd, Th, U) were analysed by means of instrumental neutron activation analysis (INAA). Mineral phases of individual ash particles were identified with the use of scanning electron microscope equipped with EDS attachment. Laser granulometric analyses were executed with the use of Analyssette analyser. The activity of the investigated fly-ash samples is several times higher than that of the bituminous coal samples; in the coal, the activities are: 226Ra - 85.4 Bq kg(-1), 40 K-689 Bq kg(-1), 232Th - 100.8 Bq kg(-1), 235U-13.5 Bq kg(-1), 238U-50 Bq kg(-1) and 228Ac - 82.4 Bq kg(-1).

  11. Radioactivity as a significant energy source in prebiotic synthesis.

    PubMed

    Garzón, L; Garzón, M L

    2001-01-01

    Radioactivity in the continental crust (due mainly to the isotopes 238U, 235U, 232Th and 40K), as a energy source for chemical evolution in the early Archean (between 3.5 and approximately 4 Ga bp), is reviewed. The most important radioactive source in the continental crust is due to the production and accumulation of radioactive gases within the crust voids (porosity). The study of such mechanism has allowed us to reach a deeper understanding about the nature of the radioactive source and to describe its behavior, particularly with regard to prebiotic chemical evolution. An effective total energy of 3 x 10(18) Ja-1 has been obtained for a depth of 1 km, 4 Ga ago. If a depth of 30 km is taken, the obtained value is almost equal to the UV solar energy radiation (lambda < 150 nm). Within the voids the radioactive source of the continental crust played a relevant role in prebiotic synthesis. In uranium deposits of the same age, the role of radioactivity must have been even more relevant in favoring chemical evolution. PMID:11296523

  12. Measurements of radiation level in petroleum products and wastes in Riyadh City Refinery.

    PubMed

    Al-Saleh, F S; Al-Harshan, G A

    2008-07-01

    Recent concern has been devoted to the hazard arising from naturally occurring radioactive materials (NORM) in oil and gas facilities. Twenty-seven petroleum samples were collected from Riyadh Refinery. Fourteen samples were products and 13 were waste samples; three of them were scale samples and 10 were sludge samples. The specific radioactivities of (238)U, (232)Th, (226)Ra, (224)Ra, (40)K, and (235)U for all samples were determined using high-resolution gamma-ray spectrometry. The radium equivalent activity, radiation hazard indices and absorbed dose rate in air for all waste samples were estimated. The radon emanation coefficient of the waste samples was estimated. It ranged between 0.574 and 0.154. The age of two scale samples was determined and found to be 2.39 and 3.66 years. The chemical structure of the waste samples was investigated using X-ray florescence analysis (XRF) and Mg, Al, Si, S, Cl, Ca and Fe were found in all samples. From this study, it was noticed that the concentrations of the natural radionuclides in the petroleum wastes were higher than that of the petroleum products.

  13. Study of some natural radionuclides near the Saudi coast of the Arabian Gulf

    NASA Astrophysics Data System (ADS)

    Al-Kheliewi, A. S.; Shabana, S. I.; Farouk, M. A.

    2012-06-01

    There is no authoritative study on marine radioactivity in the Arabian Gulf of Saudi Arabia nor is there any trusty measurements in the Red Sea's side of Saudi Arabia as well. Different surface sediment samples have been collected in three coastal areas from the the Saudi side of the Arabian Gulf‥ Those samples were collected at different depths varying from 5 to 25 meters, depending on the surface type and its geological composition, from 11 locations along the gulf coast. Activity concentrations of measured radionuclides 40K, 238U, 235U, 230Th, 226Ra, 232Th, 228Th, and 228Ra were: 23.69-253.3, 23.11 - 39.76, 1.05 - 1.65, 0.20 - 1.83, 1.99 - 9.46, 0.12 - 0.95, 0.11 - 1.15, 1.25 - 10.26 Bq/Kg respectivelty. All natural radionuclides measurements fall within the international accepted limits.

  14. Radiolytic Hydrogen Production in the South Pacific Subseafloor Basaltic Aquifer

    NASA Astrophysics Data System (ADS)

    Dzaugis, M. E.; Spivack, A. J.; Dunlea, A. G.; Murray, R. W.; D'Hondt, S.

    2015-12-01

    Hydrogen (H2) is produced in geological settings by dissociation of water due to radiation from natural radioactive decay of uranium (238U, 235U), thorium (232Th) and potassium (40K). To quantify the potential significance of radiolytic H2 as an electron donor for microbes within the South Pacific subseafloor basaltic aquifer, we calculate radiolytic H2 production rates in basement fractures utilizing measured radionuclide concentrations in 42 basalt samples from IODP Expedition 329. The samples are from three sites with very different basement ages and a wide range of alteration types. Major and trace element concentrations vary by up to an order of magnitude from sample to sample. Comparison of our samples to each other and to previous studies of fresh East Pacific Rise basalt suggests that between-sample variation in radionuclide concentrations is primarily due to differences in initial (pre-alteration) concentrations (which can vary between eruptive events), rather than to alteration type or extent. Local maxima in radionuclide (U, Th, and K) concentrations produce 'hotspots' of radiolytic H2 production; calculated radiolytic rates differ by up to a factor of 80 from sample to sample. Fracture width also greatly influences H2 production. Due to the low penetration distance of alpha radiation, microfractures are 'hotpots' for radiolytic H2 production. For example, radiolytic H2 production rates normalized to water volume are 170 times higher in 1μm-wide fractures than in 10cm-wide fractures.

  15. Evaluation of the diffuse contamination of soils caused by residues coming from the large scale production of phosphate fertilisers

    NASA Astrophysics Data System (ADS)

    Martinez, M. J.; Perez-Sirvent, C.; Martinez-Lopez, S.; Bolivar, J. P.; Mosqueda, F.; Vaca, F.; Garcia-Tenorio, R.

    2012-04-01

    The obtaining of phosphate fertilizers results in large amounts of residues that are frequently accumulated in deposits or pools occupying a wide area. These residues are acidic, and contain variable amounts of trace elements and radionuclides. The potentially polluting agents can be leached by rainwater, and so transferred to the surface waters and then to the groundwater after soil infiltration. Since the distribution and thickness of the residue deposits are variable, the contaminants cannot be easily traced back to a single, well defined source, and so a diffuse contamination (nonpoint source pollution) of the surrounding soils and waters occurs. This communication reports the results obtained in the study of soils close to the phosphogypsum deposits placed near Rio Tinto (Huelva, Spain). The zone is affected not only by the mentioned residues but also by the tides due to the vicinity of the sea. The samples studied had a low organic content and a low acidity with average values of 30 mS/cm for the EC. The mineralogical study allowed illite, goethite, quartz, gypsum and kaolinite to be identified as the main mineralogical components. Although the arsenic level was relatively high (about 600 mg/Kg) the data proved that this element is not mobilized into water. Analytical data for 238U , 234U, 235U, 228Th, 230Th, 232Th, 226Ra, 228Ra, 210Po, 40K , 137Cs were also obtained.

  16. Environmental radioactivity in southern Serbia at locations where depleted uranium was used.

    PubMed

    Sarap, Nataša B; Janković, Marija M; Todorović, Dragana J; Nikolić, Jelena D; Kovačević, Milojko S

    2014-06-01

    In the 1999 bombing of the Federal Republic of Yugoslavia, NATO forces used ammunition containing depleted uranium. The cleaning of depleted uranium that followed was performed in southern Serbia by the Vinča Institute of Nuclear Sciences between 2002 and 2007 at the locations of Pljačkovica, Borovac, Bratoselce, and Reljan. This paper presents detailed results of radioactivity monitoring four years after cleaning (2011), which included the determination of gamma emitters in soil, water, and plant samples, as well as gross alpha and beta activities in water samples. The gamma spectrometry results showed the presence of natural radionuclides 226Ra, 232Th, 40K, 235U, 238U, and the produced radionuclide 137Cs (from the Chernobyl accident). In order to evaluate the radiological hazard from soil, the radium equivalent activity, the gamma dose rate, the external hazard index, and the annual effective dose were calculated. Considering that a significant number of people inhabit the studied locations, the periodical monitoring of radionuclide content is vital. PMID:24778342

  17. Environmental radioactivity measurements and applications - Difficulties, current status and future trends

    NASA Astrophysics Data System (ADS)

    Anagnostakis, Marios J.

    2015-11-01

    For several decades natural and artificial radioactivity in the environment have been extensively studied all around the world. Nuclear accidents - mainly that of Chernobyl - have led to the development of the field of radioecology, while detector systems and techniques - with predominant that of γ-spectrometry - have been continuously developed through the years to meet researchers' needs. The study of natural radionuclides that was originally limited to 226Ra, 232Th and 40K was then extended to include radionuclides such as 234Th, 210Pb, 235U and 7Be, which allowed the study of radioactive equilibrium. Besides their importance from the radiation protection point of view, many radionuclides are also used as tracers of environmental processes, such as aerosol and transportation of air masses studies (7Be, 10Be, 22Na), soil erosion, sedimentation and geochronology (210Pb, 137Cs), marine ecosystems studies and studies related to climate change. All these studies require specialized samplings strategies and sampling preparation techniques as well as high quality measurements, while the improvement of detection limits is often of vital importance. This work is a review of environmental radioactivity measurements and applications, mainly focused in the field of γ-spectrometry, for which difficulties and limitations will be presented, together with future trends, new challenges and applications.

  18. The evaluation of half-lives and other decay data used in nuclear astrophysics and cosmochronology

    SciTech Connect

    Chechev, V. P.

    2011-12-15

    The current status of some decay data used in nuclear astrophysics and cosmochronology is presented. The half-life of {sup 79}Se has been evaluated as 3.6(3) Multiplication-Sign 10{sup 5} yr. The total energy of non-neutrino radiation released in act of {sup 37}Ar decay has been obtained being 2.709 (16) keV per disintegration. The recommended half-life values of the long-lived radionuclides (T{sub 1/2} Greater-Than-Or-Equivalent-To 10{sup 6} yr) of {sup 26}Al, {sup 40}K, {sup 53}Mn, {sup 60}Fe, {sup 87}Rb, {sup 93}Zr, {sup 98}Tc, {sup 107}Pd, {sup 129}I, {sup 135}Cs, {sup 146}Sm, {sup 176}Lu, {sup 182}Hf, {sup 187}Re, {sup 205}Pb, {sup 232}Th, {sup 235}U, {sup 238}U, {sup 244}Pu, and {sup 247}Cm are given based on the evaluations published until 2010.

  19. Radioactivity as a Significant Energy Source in Prebiotic Synthesis

    NASA Astrophysics Data System (ADS)

    Garzón, León; Garzón, M. Luisa

    2001-02-01

    Radioactivity in the continental crust (due mainly to the isotopes ^238U, ^235U, ^232Th and ^40K), as a energy source for chemical evolution in the early Archean (between 3.5 and ~4 Ga bp), is reviewed. The most important radioactive source in the continental crust is due to the production and accumulation of radioactive gases within the crust voids (porosity). The study of such mechanism has allowed us to reach a deeper understanding about the nature of the radioactive source and to describe its behavior, particularly with regard to prebiotic chemical evolution. An effective total energy of 3 × 10^18 ^Ja has been obtained for a depth of 1 km, 4 Ga ago. If a depth of 30 km is taken, the obtained value is almost equal to the UV solar energy radiation (λ<150 nm). Within the voids the radioactive source of the continental crust played a relevant role in prebiotic synthesis. In uranium deposits of the same age, the role of radiactivity must have been even more relevant in favoring chemical evolution.

  20. Radiological impacts of natural radioactivity in Abu-Tartor phosphate deposits, Egypt.

    PubMed

    Khater, A E; Higgy, R H; Pimpl, M

    2001-01-01

    Phosphate and environmental samples were collected from Abu Tartor phosphate mine and the surrounding region. The activity concentration of 226Ra (238U) series, 232Th series and 40K were measured using a gamma-ray spectrometer. The activities of uranium isotopes (238U, 235U and 234U) and 210Pb were measured using an alpha spectrometer and a low-background proportional gas counting system, respectively, after radiochemical separation. The results are discussed and compared with the levels in phosphate rocks from different countries. It seems that the Abu Tartor phosphate deposit has the lowest radioactivity level of exploited phosphate of sedimentary origin. 226Ra/238U, 210Pb/226Ra, 234U/238U and 226Ra/228Ra activity ratios were calculated and are discussed. The radioactivity levels in the surrounding region and the calculated exposure dose (nGy/h) will be considered as a pre-operational baseline to estimate the possible radiological impacts due to mining, processing and future phosphate industrial activities. To minimize these impacts, the processing wastes should be recycled to the greatest possible extent.

  1. Analysis of the 40K contamination in NaI(Tl) crystals from different providers in the frame of the ANAIS project

    NASA Astrophysics Data System (ADS)

    Cuesta, C.; Amaré, J.; Cebrián, S.; García, E.; Ginestra, C.; Martínez, M.; Oliván, M. A.; Ortigoza, Y.; Ortiz de Solórzano, A.; Pobes, C.; Puimedón, J.; Sarsa, M. L.; Villar, J. A.; Villar, P.

    2014-07-01

    NaI(Tl) large crystals are applied in the search for galactic dark matter particles through their elastic scattering off the target nuclei in the detector by measuring the scintillation signal produced. However, energies deposited in the form of nuclear recoils are small, which added to the low efficiency to convert that energy into scintillation, makes that events at or very near the energy threshold, attributed either to radioactive backgrounds or to spurious noise (nonbulk NaI(Tl) scintillation events), can compromise the sensitivity goals of such an experiment. DAMA/LIBRA experiment, using 250 kg NaI(Tl) target, reported first evidence of the presence of an annual modulation in the detection rate compatible with that expected for a dark matter signal just in the region below 6 keVee (electron equivalent energy). In the frame of the ANAIS (Annual modulation with NaI Scintillators) dark matter search project a large and long effort has been carried out in order to understand the origin of events at very low energy in large sodium iodide detectors and develop convenient filters to reject those nonattributable to scintillation in the bulk NaI(Tl) crystal. 40K is probably the most relevant radioactive contaminant in the bulk for NaI(Tl) detectors because of its important contribution to the background at very low energy. ANAIS goal is to achieve levels at or below 20 ppb natural potassium. In this paper we will report on our effort to determine the 40K contamination in several NaI(Tl) crystals, by measuring in coincidence between two (or more) of them. Results obtained for the 40K content of crystals from different providers will be compared and prospects of the ANAIS dark matter search experiment will be briefly reviewed.

  2. Distribution and possible dietary intake of radioactive 137Cs, 40K and 226Ra with the pantropical mushroom Macrocybe gigantea in SW China.

    PubMed

    Falandysz, Jerzy; Zhang, Ji; Zalewska, Tamara; Apanel, Anna; Wang, Yuanzhong; Wiejak, Anna

    2015-01-01

    There is scarcity of data on contamination with radiocesium 134/137Cs of edible mushrooms from the Southwestern Asia. This study aimed to get insight into activity concentration of artificial nuclides 134/137Cs and natural 40K and 226Ra in mushrooms from Yunnan province, which is major producer in China. The specimens of pantropical mushroom Macrocybe gigantea were collected from the wild and from a farm across Yunnan land in 2012-2013 and analyzed using gamma spectrometry with hyperpure germanium coaxial detector (HPGe). M. gigantea showed low activity concentrations of 137Cs (median value for dehydrated caps was 4.5 Bq kg(-1) and 5.4 Bq kg(-1) for stipes) while 134Cs was not detected. Natural radionuclide 40K showed 2-3 orders of magnitude greater activity concentration compared to artificial 137Cs in M. gigantea. The activity concentrations of 226Ra from uranium and radium decay series for most of the consignments of M. gigantea examined were below the method's limit of detection. The nominal effective dose equivalent for the Yunnan people from the dietary intake of 137Cs was assessed to be below 0.01 μSv per annum on the average, and that from 40K to be below 0.1 μSv per annum. Data available for the first time on activity concentrations of 137Cs in wild-grown saprobic mushroom from this region of Asia suggest low pollution with radiocesium from fallout there. Hence, the likely health risks from intake of 137Cs from cooked M. gigantea are in practice of mushrooms absent for human consumers there. Because of abundance of mushrooms in Yunnan and high significance of the region as producer and exporter a wider study using many species is necessary to fill a gap on possible radioactive contamination and risk to mushroom consumers. PMID:26061207

  3. Distribution and possible dietary intake of radioactive 137Cs, 40K and 226Ra with the pantropical mushroom Macrocybe gigantea in SW China.

    PubMed

    Falandysz, Jerzy; Zhang, Ji; Zalewska, Tamara; Apanel, Anna; Wang, Yuanzhong; Wiejak, Anna

    2015-01-01

    There is scarcity of data on contamination with radiocesium 134/137Cs of edible mushrooms from the Southwestern Asia. This study aimed to get insight into activity concentration of artificial nuclides 134/137Cs and natural 40K and 226Ra in mushrooms from Yunnan province, which is major producer in China. The specimens of pantropical mushroom Macrocybe gigantea were collected from the wild and from a farm across Yunnan land in 2012-2013 and analyzed using gamma spectrometry with hyperpure germanium coaxial detector (HPGe). M. gigantea showed low activity concentrations of 137Cs (median value for dehydrated caps was 4.5 Bq kg(-1) and 5.4 Bq kg(-1) for stipes) while 134Cs was not detected. Natural radionuclide 40K showed 2-3 orders of magnitude greater activity concentration compared to artificial 137Cs in M. gigantea. The activity concentrations of 226Ra from uranium and radium decay series for most of the consignments of M. gigantea examined were below the method's limit of detection. The nominal effective dose equivalent for the Yunnan people from the dietary intake of 137Cs was assessed to be below 0.01 μSv per annum on the average, and that from 40K to be below 0.1 μSv per annum. Data available for the first time on activity concentrations of 137Cs in wild-grown saprobic mushroom from this region of Asia suggest low pollution with radiocesium from fallout there. Hence, the likely health risks from intake of 137Cs from cooked M. gigantea are in practice of mushrooms absent for human consumers there. Because of abundance of mushrooms in Yunnan and high significance of the region as producer and exporter a wider study using many species is necessary to fill a gap on possible radioactive contamination and risk to mushroom consumers.

  4. Method for radioactivity monitoring

    DOEpatents

    Umbarger, C. John; Cowder, Leo R.

    1976-10-26

    The disclosure relates to a method for analyzing uranium and/or thorium contents of liquid effluents preferably utilizing a sample containing counting chamber. Basically, 185.7-keV gamma rays following .sup.235 U alpha decay to .sup.231 Th which indicate .sup.235 U content and a 63-keV gamma ray doublet found in the nucleus of .sup.234 Pa, a granddaughter of .sup.238 U, are monitored and the ratio thereof taken to derive uranium content and isotopic enrichment .sup.235 U/.sup.235 U + .sup.238 U) in the liquid effluent. Thorium content is determined by monitoring the intensity of 238-keV gamma rays from the nucleus of .sup.212 Bi in the decay chain of .sup.232 Th.

  5. Activity concentrations of 224Ra, 226Ra, 228Ra and 40K radionuclides in refinery products and the additional radiation dose originated from oil residues in Turkey.

    PubMed

    Parmaksiz, A; Agus, Y; Bulgurlu, F; Bulur, E; Yildiz, Ç; Öncü, T

    2013-10-01

    A total of 56 crude oil, refinery product, waste water, sludge and scale samples collected from three refineries were measured by gamma-ray spectrometry. Except for nine samples, all refinery product samples were found to have activity concentrations below the minimum detectable activity (MDA) values. The maximum (224)Ra, (226)Ra, (228)Ra and (40)K activity concentrations in crude oil and refinery product samples were measured as 11.7 ± 4.5, 14.9 ± 3.5, 11.6 ± 4.5, 248.5 ± 18.5 Bq kg(-1), respectively. The maximum (224)Ra, (226)Ra, (228)Ra and (40)K activity concentrations in scale, sludge and water samples were measured as 343.7 ± 11.8, 809.2 ± 29.0, 302.5 ± 21.6, 623.0 ± 80.9 Bq kg(-1), respectively. Radium equivalent activities of the residue samples were calculated up to 1241.8 ± 42.4 Bq kg(-1). The maximum activity concentration index and the alpha index were found to be 4.2 and 4.0, respectively. The annual effective doses of residue samples were calculated below the permitted dose rate for the public, i.e. 1 mSv y(-1).

  6. The optimization process of biodiesel production using multiple feedstock (CPO and Jatropha) with assistance of ultrasound at 40 kHz

    NASA Astrophysics Data System (ADS)

    Fajar, Berkah; Wilis, Widayat

    2016-06-01

    CPO prices are unstable, therefore affecting the supply of feedstock to produce biodiesel [2]. To overcome the shortage of feedstock, it is necessary to use multiple feedstock, in this case is CPO and Jatropha [1]. This objective of this work to optimizate biodiesel production using multifeedstock (CPO and Jatropha) with assistance of ultrasound. The optimization was to find the highest yield and the least production time. Experiments was carried out using an ultrasonic bath at a frequency of 40 kHz. The ratio of CPO and Jatropha was 1: 1, 3: 1, 4: 1 while the ratio of methanol and oil was 5: 1, 6: 1, 7: 1 and the reaction time was 50, 60, and 70 minutes. KOH was used as a catalyst. The experiment data was optimized using a Response Surface Methodology [3,4]. The optimum point was at a frequency of 40 kHz obtained at a 2.8: 1 mixture of CPO - Jatropha, 6.4: 1 molar ratio of methanol-oil and 61.5 minutes of reaction time. The results of quality testing shows that the biodiesel produced meets the ASTM standard D6751 and SNI 04-7182-2006[5].

  7. In vivo measurement technique of 40K as an indicator of the amount of skeletal muscle tissue in the human body.

    PubMed

    Sousa, W de O; Dantas, B M; Lipsztein, J L

    2003-01-01

    Potassium is an essential element for human metabolism. It is present in all living cells, predominantly in the skeletal muscle tissue. The energy of the 40K photon and its uniform distribution within the human body allow its in vivo measurement. Subjects of both sexes were monitored at the whole-body counter of the IRD facility for the evaluation of 40K body burden, being divided into two groups: (1) subjects who do not exercise routinely, and (2) subjects who do exercise routinely. The average values found for potassium mass and potassium concentration in group 1 were 99 +/- 17 g of K and 1.3 +/- 0.2 g of K kg(-1) of body mass, respectively, and in group 2 the average values found for potassium mass and potassium concentration were 118 +/- 33 g of K and 1.6 +/- 0.2 g of K kg(-1) of body mass, respectively. The comparison between average values for potassium mass and concentration shows a significant statistical difference.

  8. Activity concentrations of 226Ra, 228Th, and 40K in different food crops from a high background radiation area in Bitsichi, Jos Plateau, Nigeria.

    PubMed

    Jibiri, N N; Farai, I P; Alausa, S K

    2007-03-01

    One of the three goals of the United Nations for sustainable food security is to ensure that all people have access to sufficient, nutritionally adequate, and safe food. Decades of tin mining in the Bitsichi area of the Jos Plateau, Nigeria, have left a legacy of polluted water supplies, impoverished agricultural land, and soil containing abnormally high levels of naturally occurring radioactive elements. In order to ascertain the radiological food safety of the population, different crops that constitute the major food nutritive requirements were collected directly across farmlands in the area. The activity concentrations of (226)Ra, (228)Th, and (40)K were determined in the food and soil samples using gamma-ray spectrometry. Additionally, in situ gamma dose rate measurements were performed on the farms using a pre-calibrated survey meter. The corresponding activity concentrations in the food crops ranged from below detection limit (BDL) to 684.5 Bq kg(-1) for (40)K, from BDL to 83.5 Bq kg(-1) for (226)Ra, and from BDL to 89.8 Bq kg(-1) for (228)Th. Activity concentrations of these radionuclides were found to be lower in cereals than in tubers and vegetables. As for the soil samples, activity concentrations of these radionuclides varied from BDL to 166.4 Bq kg(-1), from 10.9 to 470.6 Bq kg(-1), and from 122.7 to 2,189.5 Bq kg(-1) for (40)K, (226)Ra, and (228)Th, respectively. Average external gamma dose rates were found to vary across the farms from 0.50 +/- 0.01 to 1.47 +/- 0.04 microSv h(-1). Due to past mining activities, the soil radioactivity in the area has been modified and the concentration level of the investigated natural radionuclides in the food crops has also been enhanced. However, the values obtained suggest that the dose from intake of these radionuclides by the food crops is low and that harmful health effects are not expected. PMID:17211656

  9. Crystallization and Preliminary X-ray Crystallographic Analysis of a 40 kDa N-Terminal Fragment of the Yeast Prion-Remodeling Factor Hsp104

    SciTech Connect

    Lee,S.; Tsai, F.

    2007-01-01

    A 40 kDa N-terminal fragment of Saccharomyces cerevisiae Hsp104 was crystallized in two different crystal forms. Native 1 diffracted to 2.6 {angstrom} resolution and belonged to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 66.6, b = 75.8, c = 235.7 {angstrom}. Native 2 diffracted to 2.9 {angstrom} resolution and belonged to space group P6{sub 1}22 or P6{sub 5}22, with unit-cell parameters a = 179.1, b = 179.1, c = 69.7 {angstrom}. This is the first report of the crystallization of a eukaryotic member of the Hsp100 family of molecular chaperones.

  10. Crystallization and preliminary X-ray crystallographic analysis of a 40 kDa N-terminal fragment of the yeast prion-remodeling factor Hsp104

    SciTech Connect

    Lee, Sukyeong; Tsai, Francis T. F.

    2007-09-01

    An N-terminal fragment of S. cerevisiae Hsp104 has been crystallized. This is the first report of the crystallization of a eukaryotic member of the Hsp100 family of molecular chaperones. A 40 kDa N-terminal fragment of Saccharomyces cerevisiae Hsp104 was crystallized in two different crystal forms. Native 1 diffracted to 2.6 Å resolution and belonged to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 66.6, b = 75.8, c = 235.7 Å. Native 2 diffracted to 2.9 Å resolution and belonged to space group P6{sub 1}22 or P6{sub 5}22, with unit-cell parameters a = 179.1, b = 179.1, c = 69.7 Å. This is the first report of the crystallization of a eukaryotic member of the Hsp100 family of molecular chaperones.

  11. Natural radioactivity measurements in the granite rock of quarry sites, Johor, Malaysia

    NASA Astrophysics Data System (ADS)

    Alnour, I. A.; Wagiran, H.; Ibrahim, N.; Laili, Z.; Omar, M.; Hamzah, S.; Idi, Bello. Y.

    2012-12-01

    This study was conducted to determine the concentration of natural radionuclides in the granite rocks of selected quarry sites in Johor state, Malaysia and their possible radiological effects. The activity concentrations of 238U, 232Th and 40K in the areas of study indicated varying values of 238U, 232Th and 40K. The highest values of 238U and 232Th concentrations (67±1 and 85±2 Bq kg-1, respectively) were observed at Kamad Quarry (IJM), whereas the highest value of 40K concentration (722±18 Bq kg-1) was detected in Kim Seng Quarry, while the values of activity concentration are lower in Hanson Quarry Products (Kulai) (25±0.5 for 238U, 24±0.5 for 232Th and 429±11 for 40K). Overall, 40K has the highest concentration in the granite rocks of the quarry sites, followed by 232Th and the least for 238U. The radium equivalent activity concentration was found in the range between 94 and 239 Bq kg-1, the absorbed dose rate was found to be in the range between 47 and 112 nGy h-1, and effective dose ranged from 58 to 137 μSv h-1. Moreover, the internal and external hazard index values were given in results lower than unity.

  12. Chemical fertilizers as a source of (238)U, (40)K, (226)Ra, (222)Rn, and trace metal pollutant of the environment in Saudi Arabia.

    PubMed

    Alshahri, Fatimh; Alqahtani, Muna

    2015-06-01

    The specific activities of (238)U, (226)Ra, (40)K, and (222)Rn in chemical fertilizers were measured using gamma ray spectrometer and Cr-39 detector. In this study, 21 chemical fertilizers were collected from Eastern Saudi Arabian markets. The specific activities of (238)U ranged from 23 ± 0.5 to 3900 ± 195 Bq kg(-1); (226)Ra ranged from 5.60 ± 2.80 to 392 ± 18 Bq kg(-1); and (40)K ranged from 18.4 ± 3 to 16,476 ± 820 Bq kg(-1). The radon concentrations and the radon exhalation rates were found to vary from 3.20 ± 1.20 to 1532 ± 160 Bq m(-3) and from 1.60 to 774 mBq m(-2) h(-1), respectively. Radium equivalent activities (Raeq) were calculated for the analyzed samples to assess the radiation hazards arising due to the use of these chemical fertilizers in the agriculture soil. The Raeq for six local samples (nitrogen, phosphorous, and potassium (NPK) and single superphosphate (SSP)) and one imported sample (Sulfate of Potash (SOP)) were greater than the acceptable value 370 Bq kg(-1). The total air absorbed doses rates in air 1 m above the ground (D) were calculated for all samples. All samples, except one imported granule sample diammonium phosphate (DAP), were higher than the estimated average global terrestrial radiation of 55 nGy h(-1). The highest annual effective dose was in triple super phosphate (TSP) fertilizers (2.1 mSv y(-1)). The results show that the local TSP, imported SOP, and local NPK (sample 13) fertilizers were unacceptable for use as fertilizers in agricultural soil. Furthermore, the toxic elements and trace metals (Pb, Cd, Cr, Co, Ni, Hg, and As) were determined using atomic absorption spectrometer. The concentrations of chromium in chemical fertilizers were higher than the global values. PMID:25532871

  13. Chemical fertilizers as a source of (238)U, (40)K, (226)Ra, (222)Rn, and trace metal pollutant of the environment in Saudi Arabia.

    PubMed

    Alshahri, Fatimh; Alqahtani, Muna

    2015-06-01

    The specific activities of (238)U, (226)Ra, (40)K, and (222)Rn in chemical fertilizers were measured using gamma ray spectrometer and Cr-39 detector. In this study, 21 chemical fertilizers were collected from Eastern Saudi Arabian markets. The specific activities of (238)U ranged from 23 ± 0.5 to 3900 ± 195 Bq kg(-1); (226)Ra ranged from 5.60 ± 2.80 to 392 ± 18 Bq kg(-1); and (40)K ranged from 18.4 ± 3 to 16,476 ± 820 Bq kg(-1). The radon concentrations and the radon exhalation rates were found to vary from 3.20 ± 1.20 to 1532 ± 160 Bq m(-3) and from 1.60 to 774 mBq m(-2) h(-1), respectively. Radium equivalent activities (Raeq) were calculated for the analyzed samples to assess the radiation hazards arising due to the use of these chemical fertilizers in the agriculture soil. The Raeq for six local samples (nitrogen, phosphorous, and potassium (NPK) and single superphosphate (SSP)) and one imported sample (Sulfate of Potash (SOP)) were greater than the acceptable value 370 Bq kg(-1). The total air absorbed doses rates in air 1 m above the ground (D) were calculated for all samples. All samples, except one imported granule sample diammonium phosphate (DAP), were higher than the estimated average global terrestrial radiation of 55 nGy h(-1). The highest annual effective dose was in triple super phosphate (TSP) fertilizers (2.1 mSv y(-1)). The results show that the local TSP, imported SOP, and local NPK (sample 13) fertilizers were unacceptable for use as fertilizers in agricultural soil. Furthermore, the toxic elements and trace metals (Pb, Cd, Cr, Co, Ni, Hg, and As) were determined using atomic absorption spectrometer. The concentrations of chromium in chemical fertilizers were higher than the global values.

  14. The cost of coolers for cooling superconducting devices at temperatures at 4.2 K, 20 K, 40 K and 77 K

    NASA Astrophysics Data System (ADS)

    Green, M. A.

    2015-12-01

    This author and other authors have written papers concerning the cost of refrigeration as a function of the refrigeration delivered. These papers have included small coolers as well. The lowest temperature range from 3.8 K to 4.7 K (the liquid helium temperature range) is covered using coolers that have two stages. The use of magnets and power equipment that use MgB2 conductors and HTS conductors have spurred the development of coolers that work well temperature ranges from 15 K to 30 K (hydrogen temperature applications), HTS conductors like BSSCO and YBCO for the range from 35 to 50 K and HTS devices from 65 K to 80 K (applications in the liquid nitrogen temperature range). This paper will present some cost data for a number of commercial two-stage and single-stage coolers. This data will be fitted to allow one to estimate the cost of coolers as a function of refrigeration for temperatures of 4.2 K, 20 K, 40 K and 77 K. The efficiency of a large number of coolers over a range of temperatures is also discussed.

  15. Effective removal of sulfur components from Brazilian power-coals by ultrasonication (40kHz) in presence of H2O2.

    PubMed

    Saikia, Binoy K; Dalmora, Adilson C; Choudhury, Rahul; Das, Tonkeswar; Taffarel, Silvio R; Silva, Luis F O

    2016-09-01

    The present investigation reports a preliminary attempt of using ultrasonic energy (40kHz) to clean some low rank high sulfur Brazilian power-coal samples in presence of H2O2 solution. All types of sulfur components (i.e. pyritic, sulfate and organic) could be removed from the coal samples by this process. The raw and ultrasonicated coal samples were characterized by chemical analysis, Fourier Transformation Infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), focused ion beam (FIB), high-resolution transmission electron microscope (HR-TEM) with selected area electron diffraction (SAED) and/or microbeam diffraction (MBD), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectrometer (EDS), and Thermogravimetry (TG-DTG) techniques to evaluate the clean-coal quality. The FT-IR spectroscopic analysis demonstrated the formation of oxidized sulfur species (SO and -SO2) and their subsequent removals after ultrasonication. The XRD profiles supported the presence of mineral matters in the coals. The TG-DTG profiles of the beneficiated coals revealed their improved quality for using in thermal plants with better combustion efficiency. PMID:27150755

  16. Activity concentration measurements of 137Cs, 90Sr and 40K in a wild food matrix reference material (Wild Berries) CCRI(II)-S8

    NASA Astrophysics Data System (ADS)

    Wätjen, U.; Altzitzogloa, T.; Ceccatelli, A.; Dikmen, H.; Ferreux, L.; Frechou, C.; García, L.; Gündogdu, G.; Kis-Benedek, G.; La Rosa, J.; Luca, A.; Moreno, Y.; Oropesa, P.; Pierre, S.; Schmiedel, M.; Spasova, Y.; Szücs, L.; Vasile, M.; Wershofen, H.; Yücel, Ü.

    2014-01-01

    In 2009, the CCRI approved a supplementary comparison to be organized by the IRMM as pilot laboratory for the activity concentrations of 137Cs, 90Sr and 40K in a matrix material of dried bilberries. The organization of this comparison and the material and measurement methods used are described. The supplementary comparison reference values (SCRV) for each of the three radionuclides are given together with the degrees of equivalence of each participating laboratory with the SCRV for the specific radionuclide. The results of this supplementary comparison allow the participating NMIs/designated institutes to declare calibration and measurement capabilities (CMCs) for the given radionuclides in a similar type of food matrix, an important aspect given the relatively few supplementary comparisons for activity in matrix materials organized so far. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  17. Effective removal of sulfur components from Brazilian power-coals by ultrasonication (40kHz) in presence of H2O2.

    PubMed

    Saikia, Binoy K; Dalmora, Adilson C; Choudhury, Rahul; Das, Tonkeswar; Taffarel, Silvio R; Silva, Luis F O

    2016-09-01

    The present investigation reports a preliminary attempt of using ultrasonic energy (40kHz) to clean some low rank high sulfur Brazilian power-coal samples in presence of H2O2 solution. All types of sulfur components (i.e. pyritic, sulfate and organic) could be removed from the coal samples by this process. The raw and ultrasonicated coal samples were characterized by chemical analysis, Fourier Transformation Infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), focused ion beam (FIB), high-resolution transmission electron microscope (HR-TEM) with selected area electron diffraction (SAED) and/or microbeam diffraction (MBD), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectrometer (EDS), and Thermogravimetry (TG-DTG) techniques to evaluate the clean-coal quality. The FT-IR spectroscopic analysis demonstrated the formation of oxidized sulfur species (SO and -SO2) and their subsequent removals after ultrasonication. The XRD profiles supported the presence of mineral matters in the coals. The TG-DTG profiles of the beneficiated coals revealed their improved quality for using in thermal plants with better combustion efficiency.

  18. Hydrogen peroxide-induced production of a 40 kDa immunoreactive thyroglobulin fragment in human thyroid cells: the onset of thyroid autoimmunity?

    PubMed Central

    Duthoit, C; Estienne, V; Giraud, A; Durand-Gorde, J M; Rasmussen, A K; Feldt-Rasmussen, U; Carayon, P; Ruf, J

    2001-01-01

    We recently reported that, during in vitro thyroid-hormone synthesis, H(2)O(2) stress cleaved thyroglobulin (Tg) into C-terminal peptides. These peptides were found to contain the immunodominant region of Tg recognized by Tg autoantibodies from patients with an autoimmune thyroid disease. To test the hypothesis that Tg fragmentation is an early upstream initiating event involved in Tg autoimmune response and the consequence of oxidative injuries, we studied the effect of H(2)O(2) stress on human thyroid cells. In culture conditions allowing Tg synthesis and iodine organification by the cells, we found that bolus addition of increasing millimolar doses of H(2)O(2) induced a dose-response appearance of floating cells in the culture medium. These cells apparently resulted from a necrotic process, and they bore iodinated Tg fragments. These fragments were found to be similar to those previously obtained in vitro from purified Tg. In both cases, Tg peptides were recognized by a well-defined monoclonal antibody directed to the immunodominant region of Tg. The smallest immunoreactive Tg peptide had a molecular mass of 40 kDa and entered human thyrocytes more efficiently than the entire Tg. These data suggest that thyrocytes exposed to locally increased H(2)O(2) doses accumulate fragmented Tg for further delivery into surrounding living thyrocytes in the course of an autoimmune response. PMID:11736644

  19. Natural radioactivity and evaluation of effective dose equivalent of granites in Turkey.

    PubMed

    Osmanlioglu, Ahmet Erdal

    2006-01-01

    Annual effective dose equivalent due to natural gamma radiation from (238)U, (232)Th and (40)K have been evaluated from granites in Turkey. Forty samples were taken for spectrometric analysis. Specific concentrations of (238)U, (232)Th and (40)K in granite samples were determined. Spectroscopy system was used with 1.8 keV (FWHM) coaxial high purity germanium (HPGe) detector. Average values of concentrations of (238)U, (232)Th and (40)K were detected at 15.85, 33.76 and 359 Bq kg(-1), respectively. The average value of radon varies from 0.073 to 0.185 Bq m(-2) h(-1) exhalation depends on the specific concentration of uranium. The dose rate due to this highest activity which have been evaluated by a Monte Carlo transport calculations does not exceed 0.4 mSv a(-1).

  20. Radioactivity risk associated with the handling of compact fluorescent lamps.

    PubMed

    Medhat, M E; Eissa, H S; Elmaghraby, E K; Abu Khadra, S A

    2012-08-01

    The objective of this work is focused in measuring the level of naturally occurring radionuclides in compact fluorescent lamps commonly used in Egypt. The activity concentration of radionuclides in the (238)U and (232)Th decay chains and from (40)K were determined through gamma-ray spectrometry measurements using high-purity germanium in a low-background configuration. It was found that the activity concentrations ranged from 45 to 198 Bq kg(-1) for (238)U, from 30 to 191 Bqkg(-1) for (232)Th and from 419 to 935 Bq kg(-1) for (40)K.

  1. Measurement of natural and 137Cs radioactivity concentrations at Izmit Bay (Marmara Sea), Turkey

    NASA Astrophysics Data System (ADS)

    Öksüz, I.; Güray, R. T.; Özkan, N.; Yalçin, C.; Ergül, H. A.; Aksan, S.

    2016-03-01

    In order to determine the radioactivity level at Izmit Bay Marmara Sea, marine sediment samples were collected from five different locations. The radioactivity concentrations of naturally occurring 238U, 232Th and 40K isotopes and also that of an artificial isotope 137Cs were measured by using gamma-ray spectroscopy. Preliminary results show that the radioactivity concentrations of 238U and 232Th isotopes are lower than the average worldwide values while the radioactivity concentrations of the 40K are higher than the average worldwide value. A small amount of 137Cs contamination, which might be caused by the Chernobyl accident, was also detected.

  2. Radiogenic Ingrowth of 40CA from Decay of 40K Provides a Powerful Tracer for Understanding the Origins of Felsic Magmas

    NASA Technical Reports Server (NTRS)

    Mills, Ryan D.; Simon, Justin I.; Depaolo, Donald J.; Bachmann, Olivier

    2013-01-01

    Over time high K/Ca continental crust produces a unique Ca isotopic reservoir, with measurable 40Ca excesses compared to Earth's mantle (?Ca=0). Thus, values of ?Cai > 1 indicate a significant crustal contribution to a magma. Values of ?Cai (<1) indistinguishable from mantle Ca indicate that the Ca in those magmas is either directly from the mantle, or is from partial melting of newly formed crust. So, whereas 40Ca excesses clearly define crustal contributions, mantle-like 40Ca/44Ca ratios are not as definitive. Here we present Ca isotopic measurements of intermediate to felsic igneous rocks from the western United States, and two crustal xenoliths found within the Fish Canyon Tuff (FCT). The two crustal xenoliths found within the 28.2 Ma FCT of the southern Rocky Mountain volcanic field (SRMVF) yield ?Ca values of 4 and 7.5, respectively. The 40Ca excesses of these possible source rocks are due to long-term in situ 40K decay and suggest that they are Precambrian in age. However, the FCT (?Cai 0.3) is within uncertainty of the mantle 40Ca/44Ca. Together, these data indicate that little Precambrian crust was involved in the petrogenesis of the FCT. Nd isotopic analyses of the FCT imply that it was generated from 10- 75% of an enriched component, and the Ca isotopic data appear to restrict that component to newly formed lower crust, or enriched mantle. However, the Ca isotopic data do permit assimilation of some crust with low Ca/Nd; decreasing the 143Nd/144Nd without adding much excess 40Ca to the FCT. Several other large tuffs from the SRMVF and from Yellowstone have ?Cai indistinguishable from the mantle. However, a few large tuffs from the SRMVF show significant 40Ca excesses. These tuffs (Wall Mountain, Blue Mesa, and Grizzly Peak) are likely sourced from near, or within the Colorado Mineral Belt. New isotopic measurements of Mesozoic and Tertiary granites from across the northern Great Basin show a range of ?Cai from 0 to 3. In these samples ?Cai is generally

  3. Verification of 235U enrichment of fresh VVER-440 fuel assemblies.

    PubMed

    Almási, I; Nguyen, C T; Zsigrai, J; Lakosi, L; Hlavathy, Z; Nagy, P; Buglyó, N

    2012-10-01

    Enrichment of uniformly and non-uniformly enriched ("profiled") fuel assemblies in a range of 1.6-4.4% was verified by gamma-ray spectrometry at a nuclear power plant (NPP). HPGe detectors and a CdZnTe (CZT) detector, the latter fitting into the central tube of the assemblies, were used for obtaining information from outer and inner fuel rods. A procedure which has minimal impact on the NPP work was developed for verifying freshly arrived assemblies under normal operational conditions, and is now in routine use.

  4. ORALLOY (93.15 235U) METAL ANNULI WITH BERYLLIUM CORE

    SciTech Connect

    John D. Bess; Leland M. Montierth; Raymond L. Reed; John T. Mihalczo

    2010-09-01

    A variety of critical experiments were constructed of enriched uranium metal during the 1960s and 1970s at the Oak Ridge Critical Experiments Facility (ORCEF) in support of criticality safety operations at the Y-12 Plant. The purposes of these experiments included the evaluation of storage, casting, and handling limits for the Y-12 Plant and providing data for verification of calculation methods and cross-sections for nuclear criticality safety applications. These included solid cylinders of various diameters, annuli of various inner and outer diameters, two and three interacting cylinders of various diameters, and graphite and polyethylene reflected cylinders and annuli. Of the hundreds of delayed critical experiments, two were performed that consisted of uranium metal annuli with a solid beryllium metal core. The outer diameter of the annuli was approximately 13 or 15 inches with an inner diameter of 7 inches. The diameter of the core was approximately 7 inches. The critical height of the configurations was approximately 5 and 4 inches, respectively. The uranium annuli consisted of multiple stacked rings with diametral thicknesses of approximately 2 inches apiece and varying heights. The 15-inch experiment was performed on June 4, 1963, and the 13-inch experiment on July 12, 1963 by J. T. Mihalczo and R. G. Taylor (Ref. 1) with accompanying logbook. Both detailed and simplified model specifications are provided in this evaluation. Both of these fast-spectra experiments were determined to represent acceptable benchmarks. The calculated eigenvalues for both the detailed and simple models are within approximately 0.6% of the benchmark values, but significantly greater than 3s from the benchmark value because the uncertainty in the benchmark is very small: <±0.0004 (1s). There is significant variability between results using different neutron cross section libraries, the greatest being a ?keff of ~0.67%. Unreflected and unmoderated experiments with the same highly enriched uranium metal parts were performed at the Oak Ridge Critical Experiments Facility in the 1960s and are evaluated in HEU MET FAST 051. Thin graphite reflected (2 inches or less) experiments also using the same highly enriched uranium metal parts are evaluated in HEU MET FAST 071. Polyethylene-reflected configurations are evaluated in HEU-MET-FAST-076. A stack of highly enriched metal discs with a thick beryllium reflector is evaluated in HEU-MET-FAST-069.

  5. ORALLOY (93.2 235U) METAL CYLINDER WITH BERYLLIUM TOP REFLECTOR

    SciTech Connect

    John D. Bess; Leland M. Montierth; Raymond Reed; John T. Mihalczo

    2010-09-01

    A variety of critical experiments were constructed of enriched uranium metal during the 1960s and 1970s at the Oak Ridge Critical Experiments Facility (ORCEF) in support of criticality safety operations at the Y-12 Plant. The purposes of these experiments included the evaluation of storage, casting, and handling limits for the Y-12 Plant and providing data for verification of calculation methods and cross-sections for nuclear criticality safety applications. These included solid cylinders of various diameters, annuli of various inner and outer diameters, two and three interacting cylinders of various diameters, and graphite and polyethylene reflected cylinders and annuli. Of the hundreds of delayed critical experiments, one experiment was comprised of a stack of approximately 7-inch-diameter metal discs. The bottom of the stack consisted of uranium with an approximate height of 4-1/8 inches. The top of the stack consisted of beryllium with an approximate height of 5-9/16 inches. This experiment was performed on August 20, 1963 by J. T. Mihalczo and R. G. Taylor (Ref. 1) with accompanying logbook. Both detailed and simplified model specifications are provided in this evaluation. This fast-spectra experiment was determined to represent an acceptable benchmark. The calculated eigenvalues for both the detailed and simple models are within approximately 0.5% of the benchmark values, but significantly greater than 3s from the benchmark value because the uncertainty in the benchmark is very small: ±0.0002 (1s). There is significant variability between results using different neutron cross section libraries, the greatest being a ?keff of ~0.65% . Unreflected and unmoderated experiments with the same highly enriched uranium metal parts were performed at the Oak Ridge Critical Experiments Facility in the 1960s and are evaluated in HEU MET FAST 051. Thin graphite reflected (2 inches or less) experiments also using the same highly enriched uranium metal parts are evaluated in HEU MET FAST 071. Polyethylene-reflected configurations are evaluated in HEU-MET-FAST-076. Highly enriched metal annuli with beryllium cores are evaluated in HEU-MET-FAST-059.

  6. 235U Holdup Measurements in Three 321-M Exhaust HEPA Banks

    SciTech Connect

    Dewberry, R

    2005-02-24

    The Analytical Development Section of Savannah River National Laboratory (SRNL) was requested by the Facilities Disposition Division to determine the holdup of enriched uranium in the 321-M facility as part of an overall deactivation project of the facility. The 321-M facility was used to fabricate enriched uranium fuel assemblies, lithium-aluminum target tubes, neptunium assemblies, and miscellaneous components for the production reactors. The results of the holdup assays are essential for determining compliance with the Waste Acceptance Criteria, Material Control & Accountability, and to meet criticality safety controls. This report covers holdup measurements of uranium residue in three HEPA filter exhaust banks of the 321-M facility. Each of the exhaust banks has dimensions near 7' x 14' x 4' and represents a complex holdup problem. A portable HPGe detector and EG&G Dart system that contains the high voltage power supply and signal processing electronics were used to determine highly enriched uranium (HEU) holdup. A personal computer with Gamma-Vision software was used to control the Dart MCA and to provide space to store and manipulate multiple 4096-channel {gamma}-ray spectra. Some acquisitions were performed with the portable detector configured to a Canberra Inspector using NDA2000 acquisition and analysis software. Our results for each component uses a mixture of redundant point source and area source acquisitions that yielded HEU contents in the range of 2-10 grams. This report discusses the methodology, non-destructive assay (NDA) measurements, assumptions, and results of the uranium holdup in these items. This report includes use of transmission-corrected assay as well as correction for contributions from secondary area sources.

  7. Radioactivity in rocks and soil and interaction with groundwater in an arid region

    NASA Astrophysics Data System (ADS)

    Alshamsi, Dalal; Murad, Ahmed; Aldahan, Ala; Hou, Xiaolin; El Saiy, Ayman

    2014-05-01

    Interaction of groundwater with soil and rocks changes the chemical composition of the water both spatially and temporally. In arid regions, surficial recharge of groundwater is generally limited to sporadic rainfall events which may cause rapid interaction between the recharge water and the aquifers materials. Among the elements that commonly increase in concentration as groundwater interact with the aquifer materials are the radioactive elements such as uranium and thorium and their decay chain products. Here, we present data on 235U, 238U, 232Th as well as 137Cs in some sediments and rock aquifers located in the United Arab Emirates (UAE) in southeastern Arabian Peninsula. The Quaternary sediments are composed of silt, sand and gravel with varying proportions of quartz, carbonates, feldspars, evaporites, while the carbonates are mainly limestones, dolomitic limestones, dolomite and calcareous mudstones. These carbonate rocks cover ages extending from 10-230 Myr. After complete digestion using fluoric and nitric acids and chemical separation, the isotopes were measured using ICP-MS. The 235U, 238U and 232Th concentrations ranges are 2.66-32.5 ng/g, 354.7-4453 ng/g and 13.2-1367 ng/g respectively in the carbonate rocks. In the sediments the concentrations are 4.6-17.5 ng/g for 235U, 631.7-2406 ng/g for 238U and 25.6-799.6 ng/g for 232Th. Although it is difficult to quantify the amounts of uranium isotopes that enter the hydrological system from the aquifers, it seems that in the presence of carboxyl ions, uranium forms highly soluble complexes which can be transported to large distances in groundwater. The variations in 232Th concentrations are probably controlled by the availability of sulfate salt rocks (like gypsum) interacting with thorium and forming soluble thorium compounds which can also explain the highly variable concentrations in groundwater.

  8. Spatial distribution of radioisotope concentrations in the offshore water and sediment of the Bay of Bengal (Indian Ocean), Bangladesh.

    PubMed

    Bhuiyan, Md Khurshid Alam; Siddique, Mohammad Abdul Momin; Zafar, Mohammad; Mustafa Kamal, Abu Hena

    2014-01-01

    Concentrations of natural and fall-out radionuclides in the offshore seawater and sediment from some parts of the Bay of Bengal, Bangladesh, were determined using a coaxial germanium detector. The average activities of (238)U, (232)Th, (40)K and (137)Cs were recorded as 31.2±5.8, 51.9±9.4, 686.4±170.5 and 0.5±0.6 Bq kg(-1) dry weight, respectively, for sediment, and 4.8±1.2, 5.4±1.2 and 39.1±8.6 Bq L(-1) for (238)U, (232)Th and (40)K, respectively, in seawater. The concentration of (137)Cs in seawater was below the detection limit. The concentration of sediment (238)U was found to be positively correlated with (232)Th ([Formula: see text], p<0.05) and (40)K (r=0.96, p<0.01), while (232)Th was positively correlated with (40)K (r=0.91, p<0.05). In sediment, the concentration of (238)U was negatively correlated (r=-0.86, p<0.05) with sea depth. In the seawater sample, the only significant relationship found was between concentration of (232)Th and water depth (r=-0.86, p<0.05). One-factor analysis of variance (ANOVA) showed that the level of radioisotope concentrations of seawater and sediment was highly significant for (238)U (F=122, df=11, p=0.01), (232)Th (F=143, df=11, p=0.01) and (40)K (F=86, df=11, p=0.01). The results showed that the level of radioactivity decreased from coast to open sea. Imminent threat due to radioactivity was not observed in these parts of the Bay of Bengal. PMID:24090093

  9. Radiolytic Hydrogen Production in the Subseafloor Basaltic Aquifer.

    PubMed

    Dzaugis, Mary E; Spivack, Arthur J; Dunlea, Ann G; Murray, Richard W; D'Hondt, Steven

    2016-01-01

    Hydrogen (H2) is produced in geological settings by dissociation of water due to radiation from radioactive decay of naturally occurring uranium ((238)U, (235)U), thorium ((232)Th) and potassium ((40)K). To quantify the potential significance of radiolytic H2 as an electron donor for microbes within the South Pacific subseafloor basaltic aquifer, we use radionuclide concentrations of 43 basalt samples from IODP Expedition 329 to calculate radiolytic H2 production rates in basement fractures. The samples are from three sites with very different basement ages and a wide range of alteration types. U, Th, and K concentrations vary by up to an order of magnitude from sample to sample at each site. Comparison of our samples to each other and to the results of previous studies of unaltered East Pacific Rise basalt suggests that significant variations in radionuclide concentrations are due to differences in initial (unaltered basalt) concentrations (which can vary between eruptive events) and post-emplacement alteration. However, there is no clear relationship between alteration type and calculated radiolytic yields. Local maxima in U, Th, and K produce hotspots of H2 production, causing calculated radiolytic rates to differ by up to a factor of 80 from sample to sample. Fracture width also greatly influences H2 production, where microfractures are hotspots for radiolytic H2 production. For example, H2 production rates normalized to water volume are 190 times higher in 1 μm wide fractures than in fractures that are 10 cm wide. To assess the importance of water radiolysis for microbial communities in subseafloor basaltic aquifers, we compare electron transfer rates from radiolysis to rates from iron oxidation in subseafloor basalt. Radiolysis appears likely to be a more important electron donor source than iron oxidation in old (>10 Ma) basement basalt. Radiolytic H2 production in the volume of water adjacent to a square cm of the most radioactive SPG basalt may support as

  10. Heating and melting of small icy satellites by the decay of 26Al

    NASA Technical Reports Server (NTRS)

    Prialnik, D.; Bar-Nun, A.; Owen, T. (Principal Investigator)

    1990-01-01

    We study the effect of radiogenic heating due to 26Al on the thermal evolution of small icy satellites. Our object is to find the extent of internal melting as a function of the satellite radius and of the initial 26Al abundance. The implicit assumption, based on observations of young stars, is that planet and satellite accretion occurred on a time scale of approximately 10(6) yr (comparable with the lifetime of 26Al). The icy satellites are modeled as spheres of initially amorphous ice, with chondritic abundances of 40K, 232Th, 235U, 238U, corresponding to an ice/dust mass ratio of 1. Evolutionary calculations are carried out, spanning 4.5 x 10(9) yr, for different combinations of the two free parameters. Heat transfer by subsolidus convection is neglected for these small satellites. Our main conclusion is that the initial 26Al abundance capable of melting icy bodies of satellite size to a significant extent is more than 10 times lower than that prevailing in the interstellar medium (or that inferred from the Ca-Al rich inclusions of the Allende meteorite, approximately 7 x 10(-7) by mass). We find, for example, that an initial 26Al mass fraction of approximately 4 x 10(-8) is sufficient for melting almost completely icy spheres with radii of 800 km, typical of the larger icy planetary satellites. We also find that for any given 26Al abundance, there is a narrow range of radii below which only marginal melting occurs and above which most of the ice melts (and refreezes later). Since extensive melting may have important consequences, such as differentiation, gas release, and volcanic activity, the effect of 26Al should be included in future studies of satellite interiors.

  11. Radiogenic heating of comets by 26Al and implications for their time of formation.

    PubMed

    Prialnik, D; Bar-Nun, A; Podolak, M

    1987-08-15

    The effect of radiogenic heating on the thermal evolution of spherical icy bodies with radii 1 km < R < 100 km was investigated. The radioisotopes considered were 26Al, 40K, 232Th, 235U, and 238U. Except for the 26Al abundance, which was varied, the other initial abundances were kept fixed, at values derived from those of chondritic meteorites and corresponding to a gas-to-dust ratio of 1. The initial models were homogeneous and isothermal (To = 10 K) amorphous ice spheres, in a circular orbit at 10(4) AU from the Sun. The main object of this study was to examine the conditions under which the transition temperature from amorphous into cubic ice (Ta = 137 K) would be reached. It was shown that the influence of the short-lived radionuclide 26Al dominates the effect of other radioactive species for bodies of radii up to approximately 50 km. Consequently, if we require comets to retain their ice in amorphous form, as suggested by observations, an upper limit of approximately 4 x 10(-9) is obtained for the initial 26Al abundance in comets, a factor of 100 lower than that of the inclusions in the Allende meteorite. A lower limit for the formation time of comets may thus be derived. The possibility of a coexistence of molten cometary cores and extended amorphous ice mantles is ruled out. Larger icy spheres (R > 100 km) reached Ta even in the absence of 26Al, due to the decay of the other radionuclides. As a result, a crystalline core formed whose relative size depended on the composition assumed. Thus the outermost icy satellites in the solar system, which might have been formed of ice in the amorphous state, have probably undergone crystallization and may have exhibited eruptive activity when the gas trapped in the amorphous ice was released (e.g., Miranda).

  12. Radiolytic Hydrogen Production in the Subseafloor Basaltic Aquifer.

    PubMed

    Dzaugis, Mary E; Spivack, Arthur J; Dunlea, Ann G; Murray, Richard W; D'Hondt, Steven

    2016-01-01

    Hydrogen (H2) is produced in geological settings by dissociation of water due to radiation from radioactive decay of naturally occurring uranium ((238)U, (235)U), thorium ((232)Th) and potassium ((40)K). To quantify the potential significance of radiolytic H2 as an electron donor for microbes within the South Pacific subseafloor basaltic aquifer, we use radionuclide concentrations of 43 basalt samples from IODP Expedition 329 to calculate radiolytic H2 production rates in basement fractures. The samples are from three sites with very different basement ages and a wide range of alteration types. U, Th, and K concentrations vary by up to an order of magnitude from sample to sample at each site. Comparison of our samples to each other and to the results of previous studies of unaltered East Pacific Rise basalt suggests that significant variations in radionuclide concentrations are due to differences in initial (unaltered basalt) concentrations (which can vary between eruptive events) and post-emplacement alteration. However, there is no clear relationship between alteration type and calculated radiolytic yields. Local maxima in U, Th, and K produce hotspots of H2 production, causing calculated radiolytic rates to differ by up to a factor of 80 from sample to sample. Fracture width also greatly influences H2 production, where microfractures are hotspots for radiolytic H2 production. For example, H2 production rates normalized to water volume are 190 times higher in 1 μm wide fractures than in fractures that are 10 cm wide. To assess the importance of water radiolysis for microbial communities in subseafloor basaltic aquifers, we compare electron transfer rates from radiolysis to rates from iron oxidation in subseafloor basalt. Radiolysis appears likely to be a more important electron donor source than iron oxidation in old (>10 Ma) basement basalt. Radiolytic H2 production in the volume of water adjacent to a square cm of the most radioactive SPG basalt may support as

  13. Outdoor radioactivity and health risks in Balikesir, northwestern Turkey.

    PubMed

    Kapdan, E; Varinlioglu, A; Karahan, G

    2012-02-01

    External irradiation from radionuclides naturally present in the environment or released from man-made practices or events is usually an important component of the exposure of human populations. These exposures derive primarily from gamma radiation arising from the decay of these radionuclides at locations outside the human body. The main objective of this study is to evaluate the radioactivity levels and health risks due to terrestrial radionuclides in the soil of Balikesir, one of the largest cities of the country, northwestern Turkey. For this purpose, activity concentrations of radionuclides in soil and outdoor gamma dose rates (terrestrial and cosmic) have been investigated in the city of Balikesir. In addition, maps for the radionuclide activity concentrations of soil and the outdoor gamma dose rate distributions have been plotted for the region. The average activities of radionuclides, (238)U, (232)Th, (40)K, (235)U and (137)Cs in the soil were determined to be 37.6 ± 10.8, 54.7 ± 15.1, 674.5 ± 203.2, 3.6 ± 1.6, 3.4 ± 2.2 Bq kg(-1), respectively, in the region. The average outdoor gamma dose rates due to terrestrial and cosmic radiations were found to be 78.5 ± 12.4 and 48.9 ± 5.8 nGy h(-1) with the total of 127.4 ± 18.9 nGy h(-1) in the region. Annual effective dose due to environmental outdoor gamma radiation exposures was determined to be 156.3 nSv. The mean estimated cancer risk values were found to be 0.063 × 10(-2) for the region using risk factors of ICRP 103. The results of the study were discussed with the studies done in other cities of Turkey and the worldwide averages. PMID:21441564

  14. Heating and melting of small icy satellites by the decay of 26Al.

    PubMed

    Prialnik, D; Bar-Nun, A

    1990-05-20

    We study the effect of radiogenic heating due to 26Al on the thermal evolution of small icy satellites. Our object is to find the extent of internal melting as a function of the satellite radius and of the initial 26Al abundance. The implicit assumption, based on observations of young stars, is that planet and satellite accretion occurred on a time scale of approximately 10(6) yr (comparable with the lifetime of 26Al). The icy satellites are modeled as spheres of initially amorphous ice, with chondritic abundances of 40K, 232Th, 235U, 238U, corresponding to an ice/dust mass ratio of 1. Evolutionary calculations are carried out, spanning 4.5 x 10(9) yr, for different combinations of the two free parameters. Heat transfer by subsolidus convection is neglected for these small satellites. Our main conclusion is that the initial 26Al abundance capable of melting icy bodies of satellite size to a significant extent is more than 10 times lower than that prevailing in the interstellar medium (or that inferred from the Ca-Al rich inclusions of the Allende meteorite, approximately 7 x 10(-7) by mass). We find, for example, that an initial 26Al mass fraction of approximately 4 x 10(-8) is sufficient for melting almost completely icy spheres with radii of 800 km, typical of the larger icy planetary satellites. We also find that for any given 26Al abundance, there is a narrow range of radii below which only marginal melting occurs and above which most of the ice melts (and refreezes later). Since extensive melting may have important consequences, such as differentiation, gas release, and volcanic activity, the effect of 26Al should be included in future studies of satellite interiors.

  15. The early thermal evolution of Mars

    NASA Astrophysics Data System (ADS)

    Bhatia, G. K.; Sahijpal, S.

    2016-01-01

    Hf-W isotopic systematics of Martian meteorites have provided evidence for the early accretion and rapid core formation of Mars. We present the results of numerical simulations performed to study the early thermal evolution and planetary scale differentiation of Mars. The simulations are confined to the initial 50 Myr (Ma) of the formation of solar system. The accretion energy produced during the growth of Mars and the decay energy due to the short-lived radio-nuclides 26Al, 60Fe, and the long-lived nuclides, 40K, 235U, 238U, and 232Th are incorporated as the heat sources for the thermal evolution of Mars. During the core-mantle differentiation of Mars, the molten metallic blobs were numerically moved using Stoke's law toward the center with descent velocity that depends on the local acceleration due to gravity. Apart from the accretion and the radioactive heat energies, the gravitational energy produced during the differentiation of Mars and the associated heat transfer is also parametrically incorporated in the present work to make an assessment of its contribution to the early thermal evolution of Mars. We conclude that the accretion energy alone cannot produce widespread melting and differentiation of Mars even with an efficient consumption of the accretion energy. This makes 26Al the prime source for the heating and planetary scale differentiation of Mars. We demonstrate a rapid accretion and core-mantle differentiation of Mars within the initial ~1.5 Myr. This is consistent with the chronological records of Martian meteorites.

  16. Radiolytic Hydrogen Production in the Subseafloor Basaltic Aquifer

    PubMed Central

    Dzaugis, Mary E.; Spivack, Arthur J.; Dunlea, Ann G.; Murray, Richard W.; D’Hondt, Steven

    2016-01-01

    Hydrogen (H2) is produced in geological settings by dissociation of water due to radiation from radioactive decay of naturally occurring uranium (238U, 235U), thorium (232Th) and potassium (40K). To quantify the potential significance of radiolytic H2 as an electron donor for microbes within the South Pacific subseafloor basaltic aquifer, we use radionuclide concentrations of 43 basalt samples from IODP Expedition 329 to calculate radiolytic H2 production rates in basement fractures. The samples are from three sites with very different basement ages and a wide range of alteration types. U, Th, and K concentrations vary by up to an order of magnitude from sample to sample at each site. Comparison of our samples to each other and to the results of previous studies of unaltered East Pacific Rise basalt suggests that significant variations in radionuclide concentrations are due to differences in initial (unaltered basalt) concentrations (which can vary between eruptive events) and post-emplacement alteration. However, there is no clear relationship between alteration type and calculated radiolytic yields. Local maxima in U, Th, and K produce hotspots of H2 production, causing calculated radiolytic rates to differ by up to a factor of 80 from sample to sample. Fracture width also greatly influences H2 production, where microfractures are hotspots for radiolytic H2 production. For example, H2 production rates normalized to water volume are 190 times higher in 1 μm wide fractures than in fractures that are 10 cm wide. To assess the importance of water radiolysis for microbial communities in subseafloor basaltic aquifers, we compare electron transfer rates from radiolysis to rates from iron oxidation in subseafloor basalt. Radiolysis appears likely to be a more important electron donor source than iron oxidation in old (>10 Ma) basement basalt. Radiolytic H2 production in the volume of water adjacent to a square cm of the most radioactive SPG basalt may support as many as

  17. Properties of Natural Radiation and Radioactivity

    SciTech Connect

    Strom, Daniel J.

    2009-07-13

    Ubiquitous natural sources of radiation and radioactive material (naturally occurring radioactive material, NORM) have exposed humans throughout history. To these natural sources have been added technologically-enhanced naturally occurring radioactive material (TENORM) sources and human-made (anthropogenic) sources. This chapter describes the ubiquitous radiation sources that we call background, including primordial radionuclides such as 40K, 87Rb, the 232Th series, the 238U series, and the 235U series; cosmogenic radionuclides such as 3H and 14C; anthropogenic radionuclides such as 3H, 14C, 137Cs, 90Sr, and 129I; radiation from space; and radiation from technologically-enhanced concentrations of natural radionuclides, particularly the short-lived decay products of 222Rn ("radon") and 220Rn ("thoron") in indoor air. These sources produce radiation doses to people principally via external irradiation or internal irradiation following intakes by inhalation or ingestion. The effective doses from each are given, with a total of 3.11 mSv y-1 (311 mrem y-1) to the average US resident. Over 2.5 million US residents receive over 20 mSv y-1 (2 rem y-1), primarily due to indoor radon. Exposure to radiation from NORM and TENORM produces the largest fraction of ubiquitous background exposure to US residents, on the order of 2.78 mSv (278 mrem) or about 89%. This is roughly 45% of the average annual effective dose to a US resident of 6.2 mSv y-1 (620 mrem y-1) that includes medical (48%), consumer products and air travel (2%), and occupational and industrial (0.1%). Much of this chapter is based on National Council on Radiation Protection and Measurements (NCRP) Report No. 160, "Ionizing Radiation Exposure of the Population of the United States," for which the author chaired the subcommittee that wrote Chapter 3 on "Ubiquitous Background Radiation."

  18. The low-level radioactivity ocean sediment standard reference material

    SciTech Connect

    Inn, K.G.W.; Lin, Z.; Liggett, W.S.; Krey, P.W.

    1995-12-31

    Over the past decades, on the order of 10{sup 15} Becquerel nuclear waste have been stored in the oceans. Potential contamination of the oceans from leaking nuclear waste has caused world wide concern. Currently, early warning of ocean contamination near the waste dumping sites rely on monitoring systems being set up by different countries and agencies. Because the determination of low-level radioactivity in ocean sediment is a difficult technical task, a basis for measurement quality assurance, methods verification, and data comparability is needed. The recently certified NIST ocean sediment Standard Reference Material (SRM-4355) is a composite of 1% contaminated Irish Sea sediment and 99% of Chesapeake Bay sediment by weight. The sediments were blended, pulverized to a median particle size of 8 {mu}m, and reblended to achieve acceptable sample homogeneity. A statistical assessment of the intercomparison results from 19 laboratories has shown the material to be homogeneous down to 10 grams. The certified radionuclide concentration range from 0.4 to 230 mBq/g. A variety of radiochemical procedures and detection techniques have been used in the measurements to minimize possible systematic bias. Twelve radionuclides including {sup 40}K, {sup 90}Sr, {sup 137}Cs, {sup 226}Ra, {sup 228}Th, {sup 230}Th, {sup 232}Th, {sup 234}U, {sup 235}U, {sup 238}U, {sup 238}Pu, and {sup (239+240)}Pu were certified. The mean values were reported for an additional 10 uncertified radionuclides: {sup 129}I, {sup 155}Eu, {sup 210}Po, {sup 210}Pb, {sup 212}Pb, {sup 214}Pb, {sup 214}Bi, {sup 228}Ra, {sup 237}Np, and {sup 241}Am. The standard reference material in unit quantities of about 100 gram each will be available by the end of 1995.

  19. Outdoor radioactivity and health risks in Balikesir, northwestern Turkey.

    PubMed

    Kapdan, E; Varinlioglu, A; Karahan, G

    2012-02-01

    External irradiation from radionuclides naturally present in the environment or released from man-made practices or events is usually an important component of the exposure of human populations. These exposures derive primarily from gamma radiation arising from the decay of these radionuclides at locations outside the human body. The main objective of this study is to evaluate the radioactivity levels and health risks due to terrestrial radionuclides in the soil of Balikesir, one of the largest cities of the country, northwestern Turkey. For this purpose, activity concentrations of radionuclides in soil and outdoor gamma dose rates (terrestrial and cosmic) have been investigated in the city of Balikesir. In addition, maps for the radionuclide activity concentrations of soil and the outdoor gamma dose rate distributions have been plotted for the region. The average activities of radionuclides, (238)U, (232)Th, (40)K, (235)U and (137)Cs in the soil were determined to be 37.6 ± 10.8, 54.7 ± 15.1, 674.5 ± 203.2, 3.6 ± 1.6, 3.4 ± 2.2 Bq kg(-1), respectively, in the region. The average outdoor gamma dose rates due to terrestrial and cosmic radiations were found to be 78.5 ± 12.4 and 48.9 ± 5.8 nGy h(-1) with the total of 127.4 ± 18.9 nGy h(-1) in the region. Annual effective dose due to environmental outdoor gamma radiation exposures was determined to be 156.3 nSv. The mean estimated cancer risk values were found to be 0.063 × 10(-2) for the region using risk factors of ICRP 103. The results of the study were discussed with the studies done in other cities of Turkey and the worldwide averages.

  20. 40Ar/ 39Ar ages of CAMP in North America: Implications for the Triassic-Jurassic boundary and the 40K decay constant bias

    NASA Astrophysics Data System (ADS)

    Jourdan, F.; Marzoli, A.; Bertrand, H.; Cirilli, S.; Tanner, L. H.; Kontak, D. J.; McHone, G.; Renne, P. R.; Bellieni, G.

    2009-06-01

    a minor CAMP late tailing activity (190-194 Ma) which has been observed already for dykes and sills in Africa and Brazil. We speculate that, if genuine, this late activity can be due to a major extensional event, possibly heralding the oceanization process at ~ 190 Ma. Comparison between high quality U/Pb and 40Ar/ 39Ar ages of pegmatite lenses from the North Mountain basalts confirms a ~ 1% bias between the two chronometers. This discrepancy is likely attributed to the miscalibration of the 40K decay constants, in particular the electron capture branch.

  1. Rheological structure in Mars and its time evolution

    NASA Astrophysics Data System (ADS)

    Azuma, S.; Katayama, I.

    2014-12-01

    Mars is one of the terrestrial planets which are composed of rock and metal such as the Earth. There is no water, no life, and no plate tectonics on Mars, suggesting that Mars and Earth followed different evolutionary paths. Rheological structure, which indicates the deformation behavior and the strength of planetary interior, plays an important role in the evolution of planets. The rheological behavior of planetary interiors is strongly sensitive to temperature, which may produce strong rheological layering. Rheological structure of Mars in past must be different from the current rheological structure. First, the evolutions of temperature profiles in Mars are inferred from the surface heat flow and the heat conduction equation. The surface heat flow of Mars every 1 billion years was calculated from present abundances of the radioactive isotopes (235U, 235U, 232Th, and 40K) and their half-lives (Hahn et al 2011). Based on the temperature profile, we calculate the rheological structure of Mars every 1 billion years using flow-law of plagioclase and olivine. Calculated rheological structure shows that the brittle-ductile transition of present Mars, which is transition of deformation behavior from brittle failure to viscous flow, is deeper as compared with that of past Mars, suggesting that current elastic thickness also becomes thicker than that of past Mars. Under water-saturated conditions, the rheological structure which simulates the northern lowlands shows the strength contrast between the crust and mantle, indicating that the decoupling might occur at the Moho from 4 Ga to present day. Under dry conditions, lithosphere of northern lowlands has no strength contrast at the Moho, implying that crust and mantle might be coupled from 3 Ga to present day. Viscosity contrast between the surface and planetary interior is key for the mantle convection style (Moresi and Solomatov 1995), and the calculated viscosity contrast at present Mars is ~10-5 (Pa), suggesting that

  2. Natural activity concentrations in bottled drinking water and consequent doses.

    PubMed

    Kabadayi, Önder; Gümüs, Hasan

    2012-07-01

    The radioactivity concentrations of nuclides (238)U, (232)Th and (40)K in bottled drinking water from six different manufacturers from Turkey were measured using high-resolution gamma-ray spectrometry. The measurement was done using a coaxial high-purity germanium detector system coupled to Ortec-Dspect jr digital MCA system. The average measured activity concentrations of the nuclides (238)U, (232)Th and (40)K are found to be 0.781, 1.05 and 2.19 Bq l(-1), respectively. The measured activity concentrations have been compared with similar studies from different locations. The annual effective doses for ingestion of radionuclides in the water are found to be 0.0246 mSv for (238)U and 0.169 mSv for (232)Th.

  3. Distribution of uranium and thorium in groundwater of arid climate region

    NASA Astrophysics Data System (ADS)

    Murad, Ahmed; Alshamsi, Dalal; Aldahan, Ala; Hou, Xiaolin

    2014-05-01

    Uranium, thorium and their decay products are the most common radionuclides in groundwater in addition to potassium-40. Once groundwater is used for drinking, domestic and irrigation purposes, the radionuclides will then pose environmental and health related hazard originating from radioactivity and toxicity. In the investigation presented here, assessment of 238U, 235U and 232Th concentrations in groundwater across of the United Arab Emirates (UAE) is evaluated in terms of quality and sources. The region is dominated by arid climate conditions and radioactivity assessment of groundwater is essential for safe use of groundwater. Furthermore, the results were linked to data from other arid regions and worldwide. Groundwater samples (total dissolved solids,TDS, 142.5 mg L-1 to 12770 mg L-1) from 67 different wells were collected across geomorphologically different areas and most of the wells are actively used for agriculture. The aquifers are recent sand dunes, Quaternary (3 million years to present) sediments, and older carbonate rocks (230-10 million years). The 235U, 238U and 232Th measurements were carried out using ICP-MS system equipped with an Xt-skimmer cone and a concentric nebulizer under hot plasma conditions. Concentrations of 235U, 238U and 232Th range at (0.125-508.4) ng L-1, (25.81-69237) ng L-1 and (0.236-2529) ng L-1, respectively. Apparently, most 235U, 238U, 232Th concentrations in the sampled groundwater are below the WHO proposed permissible level of 60000 ng/L for total uranium (1 Bq L-1 for 235U and 10 Bq L-1 for 238U) and 5000 ng L-1 (1Bq L-1) for 232Th. A few samples show high concentrations of uranium that are associated with high TDS values and occur within interbedded limestones and shales aquifer. Comparison with worldwide groundwater data suggests that 238U concentration is highest in the arid regions groundwater where the recharge to aquifers is relatively low. The situation for 232Th concentrations seems less affected by climatic

  4. Natural radioactivity and chemical concentrations in Egyptian groundwater.

    PubMed

    Amin, Rafat M; Khalil, F A; El Fayoumi, M A K

    2011-02-01

    Measurements of natural radioactivity in drinking water have been performed in many parts of the world, mostly for assessment of the doses and risk resulting from consuming water. A study of the radionuclide and chemical components in groundwater from Beni Suef Governate, Egypt has been carried out. Fifty water samples were analyzed by gamma ray spectroscopy to determine the 226Ra, 232Th, and 40K concentrations; major elements, pH, alkalinity, and conductivity were also measured. The specific activity values ranged from 0.008 to 0.040 Bq/l for 226Ra, from 0.003 to 0.019 Bq/l for 232Th, and from 0.025 to 0.344 Bq/l for 40K. The annual ingestions of these radionuclides, using local consumption rates (average over the whole population) of 1.5 l day(-1), were estimated to be 8.59, 4.86, and 83.47 Bq year(-1) for 226Ra, 232Th, and 40K, respectively. The estimated values and weighted means of these radionuclides compare well with the world average. The estimated effective doses from drinking water were found to be 2.4 μSv year(-1) (226Ra), 1.1 μSv year(-1) (232Th), and 0.51 μSv year(-1) (40K). Contribution of these radionuclides to the committed effective dose from 1 year consumption of drinking water is estimated to be only 4%.

  5. Distribution, enrichment and principal component analysis for possible sources of naturally occurring and anthropogenic radionuclides in the agricultural soil of Punjab state, India.

    PubMed

    Kumar, Ajay; Joshi, Vikram M; Mishra, Manish K; Karpe, Rupali; Rout, Sabyasachi; Narayanan, Usha; Tripathi, Raj M; Singh, Jaspal; Kumar, Sanjeev; Hegde, Ashok G; Kushwaha, Hari S

    2012-06-01

    Enrichment factor (EF) of elements including geo-accumulation indices for soil quality and principal component analysis (PCA) were used to identify the contributions of the origin of sources in the studied area. Results of (40)K, (137)Cs, (238)U and (232)Th including their decay series isotopes in the agricultural soil of Mansa and Bathinda districts in the state of Punjab were presented and discussed. The measured mean radioactivity concentrations for (238)U, (232)Th and (40)K in the agricultural soil of the studied area differed from nationwide average crustal abundances by 51, 17 and 43 %, respectively. The sequence of the EFs of radionuclides in soil from the greatest to the least was found to be (238)U > (40)K > (226)Ra > (137)Cs > (232)Th > (228)Ra. Even though the enrichment of naturally occurring radionuclides was found to be higher, they remained to be in I(geo) class of '0', indicating that the soil is uncontaminated with respect to these radionuclides. Among non-metals, N showed the highest EF and belonged to I(geo) class of '2', indicating that soil is moderately contaminated due to intrusion of fertiliser. The resulting data set of elemental contents in soil was also interpreted by PCA, which facilitates identification of the different groups of correlated elements. The levels of the (40)K, (238)U and (232)Th radionuclides showed a significant positive correlation with each other, suggesting a similar origin of their geochemical sources and identical behaviour during transport in the soil system.

  6. Activity levels of some radionuclides in Mariout and Brullus lakes, Egypt.

    PubMed

    Dar, Mahmoud A; El Saharty, Abeer A

    2013-11-01

    Mariout and Brullus are two of the highly fish-productive lakes in the northern coast of Egypt along the Mediterranean Sea. They are widely used to drain industrial wastes, sewage and agriculture drainage. The activities of (238)U, (232)Th, (40)K and (137)Cs were measured in the uppermost part of the surface sediments of the two lakes, using gamma-ray spectrophotometry. Brullus Lake recorded significantly higher (238)U and (232)Th and lower (40)K (17.22±2.49, 10.03±0.56 and 299.70±17.78 Bq kg(-1)) than Mariout Lake (12.65±1.53, 7.24±0.76 and 518.75±46.24 Bq kg(-1), respectively). Cesium-137 shows nearly equal activities in both lakes (3.33±0.46 and 3.68±0.70 Bq kg(-1), respectively). Activity distributions of (238)U and (232)Th in the sediments of Mariout Lake show a significant increase to the west, southwest and northeast, (40)K activity increased westwards, while the (137)Cs level was increased to the east and northeast, indicating agriculture drainage, industrial wastes and lands reclamation around the lake. At Brullus Lake, the activity trends of (238)U, (232)Th, (40)K and(137)Cs were increasing to the west and south towards the agriculture and industrial waste-water-feeding drains. PMID:23630385

  7. Variation of uranium isotopic composition in soil within the JCO grounds from the 30 September 1999 criticality accident at JCO, Tokai-mura, Japan.

    PubMed

    Yamamoto, Masayoshi; Kawabata, Yoshiko; Murata, Yoshimasa; Komura, Kazuhisa

    2002-08-01

    Following the 30 September 1999 criticality accident at JCO, 29 surface and 3 core soil samples were collected inside and outside the JCO grounds to evaluate possible contamination by 235U-enriched uranium (18.8%) being handled at the time of the accident. Uranium (234U, 235U, and 238U) and thorium (228Th, 230Th, and 232Th) isotopes were determined by alpha-spectrometry and ICP-MS after radiochemical separation. Concentrations of 238U and 234U ranged from 11.3 to 63.5 and 11.6 to 360 mBq g(-1), respectively. Higher amounts of 238U and/or 234U were found in the vicinity of the uranium conversion building. The calculated 234U/235U activity ratios ranged from a 1.0 radioactive equilibrium value to an unusually high 5.7 value. Several of the soil samples showed considerably higher 235U/238U atomic ratios (1.06-4.37%) than 0.725% for natural uranium. Based on the assumption that measured U-series nuclides in soil samples taken from the JCO grounds were almost at radioactive equilibrium up to 230Th, excess uranium could be calculated for each sample. The results suggest that the excess uranium in the soils have lower 235U/238U atomic ratios (a few %) than the 18.8% enrichment of the precipitation tank uranium.

  8. Neutron capture by fissile and fertile actinide targets

    SciTech Connect

    Maslov, Vladimir M.

    2009-01-28

    For fissile actinide targets {sup 233}U, {sup 235}U and {sup 239}Pu the capture cross sections are strongly influenced by the target spin, fission transition states spectroscopy and fission/{gamma}-emission competition of the compound nuclides. The capture cross sections were obtained via a consistent description of fission and elastic/inelastic scattering, (n,{gamma}f) reaction being included.For neutron capture reactions on even-even U, Pu and Cm nuclei the methods, proven in case of {sup 232}Th(n,{gamma}) and {sup 238}U(n,{gamma}) data analysis are used. Calculated {sup 240}Pu(n,{gamma}) and {sup 244}Cm(n,{gamma}) reaction cross sections shapes are much similar to that, observed for the {sup 238}U(n,{gamma}) and {sup 232}Th(n,{gamma}) reactions. Differences are due to fission and neutron emission competition, which depends on the (Z,N)-composition of the compound nucleus.

  9. Experimental Studies of the Phase Diagram Leucite - Nepheline - Diopside under 4.0GPa and High Temperatures

    NASA Astrophysics Data System (ADS)

    Conceicao, R. V.; Wilbert de Souza, M. R.; Cedeno, D. G.; Schmitz Quinteiro, R. V.

    2015-12-01

    One of the most important heat sources for the Earth's interior is the radioactive decay of radiogenic elements, mainly 235U, 238U, 232Th and 40K radionuclides. However, our planet emits much more heat than that expected for the energy produced by the calculated concentration of these elements in the Earth's Mantle, even if we consider solar radiation and planetary accretion energy too. Such data suggest that the concentration of all these elements, or some of them, is underestimated and several authors suggest that some of these elements could be enriched even in the Earth's core, despite their lithophyle characteristics. In this study, we focus on the potassium behavior, concentration in the mantle and we aim to find stable mineral phases under high pressure and temperature, able to keep potassium (and by consequence its radioactive 40K isotope) and water in their structure in the mantle conditions. In such way, we will be able to better understand the role of potassium in the mantle as a heat source to the Earth's interior. We conducted experimental runs in which synthetic vitreous samples, stoichiometrically equivalent to different concentrations of leucite, nepheline and diopside, are processed in a 1000 tonf hydraulic press, under 4.0 GPa (equivalent to 120 km Earth deep) and temperatures up to 1400 °C. As run products, we obtained euhedral minerals in equilibrium with a liquid (melt), simulating a potassium enriched mantle environment. The samples are analyzed by XRD, SEM-EDS and EPMA techniques, and the produced data is used to construct the "Leucite-Nepheline-Diopside under 4.0GPa and dry conditions" ternary phase diagram. Preliminary semiquantitative data (EDS), plotted in the diagram, show that clinopyroxene keeps up to 2wt% of K2O in its structure in absence of potassic phases and in the presence of nepheline. The amount of K2O decreases to 0,1wt% if kalsilite is present, which is the potassic stable phase in the experiment conditions. Compared to

  10. Experimental study of the Pb and Bi breeding zones effect on the neutron parameters of a molten-salt blanket in a fusion reactor

    NASA Astrophysics Data System (ADS)

    Novikov, V. M.; Sheehov, S. B.; Romodanov, V. L.; Zagryadsky, V. A.; Chuvilin, D. Yu.

    1980-07-01

    The fluorid salt melt of Li, Be, U and Th is considered as one of the possible coolants both for a "clean" and for a "hybrid" fusion reactor. The tritium reproduction coefficient Kτ is only a little greater than unity in the molten-salt blanket, because of inelastic scattering on a fluorine nucleus which depresses the 7Li(n, n' α) T reaction. To compensate for this effect the neu tron multiplication Pb, Be and 238U zones may be used [2,4]. This article is devoted to the experimental study of the Pb and Bi neutron multiplication zones in the molten-salt blanket model, consisting of an aluminium sphere, filled with a eutectical mixture of LiF and BeF 2. The blanket model diameter was 400 mm. The 23 mm multiplication zones were placed into the cavity of the model. The neutron generator NGI-200 was used as a 14 MeV neutron source. The neutron output was 10 10 n/s. The deuteron energy was 140 keV and the average target current value was 500 uA. The detection of neutrons was performed by small impulsive fission chambers KNT-2 with 232Th and KNT-5 with 235U. The neutron generator output measurements were made with the helpof the attendant α-particle technique using silicon semiconductor detector DKP25. It was experimentally shown that there is a noticeable influence of the Pb and Bi multiplication zones on the fission rates of 232Th and 235U. The spacial distribution of the fission rates of 232Th and 235U measured in this experiment was compared with that calculated by means of the program "BLANK". This comparison showed good agreement between experimental and calculated values at a large distance from the neutron source and a noticeable distinction near it. It was also shown that the experimental value of the Pb influence was larger by an average 15% for 232Th and less by an average 10% for 235U, than that calculated.

  11. Hope and Inquietudes in Nucleocosmochronology

    NASA Astrophysics Data System (ADS)

    Arnould, M.; Goriely, S.

    Critical views are presented on some nucleo-cosmochronological questions. Progress has been made recently in the development of the 187Re-187Os cosmochronometry. From this, there is good hope for this clock to become of the highest quality for the nuclear dating of the Universe. The simultaneous observation of Th and U in ultra-metal-poor stars would also be a most interesting prospect. In contrast, a serious inquietude is expressed about the reliability of the chronometric attempts based on the classical 232Th-238U and 235U-238U pairs, as well as on the Th (without U) abundance determinations in ultra-metal poor stars.

  12. Initiation of nuclear reactions in femtosecond laser plasma

    SciTech Connect

    Golovinski, P. A.; Mikhin, E. A.

    2013-01-15

    Mechanisms of electron interaction with a nucleus via a direct electron-nucleus collision and via bremsstrahlung generated in electron scattering on a nucleus in a femtosecond laser plasma are considered. The description of this interaction is simplified substantially by using the instantaneous-impact and equivalent-photon approximations. The yields of photons, electron-positron pairs, and products of nuclear reactions initiated by a laser pulse for some nuclei are calculated. In particular, this is done for {sup 235}U, {sup 236}U, {sup 238}U, and {sup 232}Th fission in a laser field of intensity 10{sup 20} to 10{sup 22} W/cm{sup 2}.

  13. Age of the moon: an isotopic study of uranium-thorium-lead systematics of lunar samples.

    PubMed

    Tatsumoto, M; Rosholt, J N

    1970-01-30

    Concentrations of U, Th, and Pb in Apollo 11 samples studied are low (U. 0.16 to 0.87; Th, 0.53 to 3.4; Pb, 0.29 to 1.7, in ppm) but the extremely radiogenic lead in samples allows radiometric dating. The fine dust and the breccia have a concordant age of 4.66 billion years on the basis of (207)Pb/(206)Pb, (206)Pb/(238)U, (207)Pb/(235U), and(208)Pb/(232)Th ratios. This age is comparable with the age of meteorites and with the age generally accepted for the earth. Six crystalline and vesicular samples are distinctly younger than the dust and breccia. The (238)U/(235)U ratio is the same as that in earth rocks, and (234)U is in radioactive equilibrium with parent (238)U.

  14. Age of the moon: An isotopic study of uranium-thorium-lead systematics of lunar samples

    USGS Publications Warehouse

    Tatsumoto, M.; Rosholt, J.N.

    1970-01-01

    Concentrations of U, Th, and Pb in Apollo 11 samples studied are low (U. 0.16 to 0.87; Th, 0.53 to 3.4; Pb, 0.29 to 1.7, in ppm) but the extremely radiogenic lead in samples allows radiometric dating. The fine dust and the breccia have a concordant age of 4.66 billion years on the basis of 207Pb/206Pb, 206Pb/238U, 207Pb/235U, and 208Pb/232Th ratios. This age is comparable with the age of meteorites and with the age generally accepted for the earth. Six crystalline and vesicular samples are distinctly younger than the dust and breccia. The 238U/235U ratio is the same as that in earth rocks, and 234U is in radioactive equilibrium with parent 238U.

  15. The 40 kW Giromill

    NASA Astrophysics Data System (ADS)

    Anderson, J.

    A prototype Giromill wind turbine is discussed. The Giromill is a vertical axis wind turbine with articulating vertical blades programmed through a microprocessor to catch the wind from any direction and maintain constant rotor RPM. The articulating blades provide not only a very high energy conversion efficiency but also a self-starting capability and additional safety by allowing the blades to weathervane in high winds. The blades are straight and simple structures with no twist and, much like the remaining structure, is less complex than many other windmills. Power transmission, control system, and electrical generator are located at the ground level for convenient access and maintenance. Direct mechanical power is also available at ground level for irrigation pumping.

  16. Investigation of a new lead-free Bi0.5(Na0.40K0.10)TiO3-(Ba0.7Sr0.3)TiO3 piezoelectric ceramic

    PubMed Central

    2012-01-01

    Lead-free piezoelectric compositions of the (1-x)Bi0.5(Na0.40K0.10)TiO3-x(Ba0.7Sr0.3)TiO3 system (when x = 0, 0.05, 0.10, 0.15, and 0.20) were fabricated using a solid-state mixed oxide method and sintered between 1,050°C and 1,175°C for 2 h. The effect of (Ba0.7Sr0.3)TiO3 [BST] content on phase, microstructure, and electrical properties was investigated. The optimum sintering temperature was 1,125°C at which all compositions had densities of at least 98% of their theoretical values. X-ray diffraction patterns that showed tetragonality were increased with the increasing BST. Scanning electron micrographs showed a slight reduction of grain size when BST was added. The addition of BST was also found to improve the dielectric and piezoelectric properties of the BNKT ceramic. A large room-temperature dielectric constant, εr (1,609), and piezoelectric coefficient, d33 (214 pC/N), were obtained at an optimal composition of x = 0.10. PMID:22221833

  17. High-performance batteries for electric-vehicle propulsion and stationary energy storage. Progress report, October 1978-September 1979. [40 kWh, Li-Al and Li-Si anodes

    SciTech Connect

    Barney, D. L.; Steunenberg, R. K.; Chilenskas, A. A.; Gay, E. C.; Battles, J. E.; Hornstra, F.; Miller, W. E.; Vissers, D. R.; Roche, M. F.; Shimotake, H.; Hudson, R.; Askew, B. A.; Sudar, S.

    1980-03-01

    The research, development, and management activities of the programs at Argonne National Laboratory (ANL) and at contractors' laboratories on high-temperature batteries during the period October 1978 to September 1979 are reported. These batteries are being developed for electric-vehicle propulsion and for stationary energy-storage applications. The present cells, which operate at 400 to 500/sup 0/C, are of a vertically oriented, prismatic design with one or more inner positive electrodes of FeS or FeS/sub 2/, facing negative electrodes of lithium-aluminum or lithium-silicon alloy, and molten LiCl-KC1 electrolyte. During this reporting period, cell and battery development work has continued at ANL and contractors' laboratories. A 40 kWh electric-vehicle battery (designated Mark IA) was fabricated and delivered to ANL for testing. During the initial heat-up, one of the two modules failed due to a short circuit. A failure analysis was conducted, and the Mark IA program completed. Development work on the next electric-vehicle battery (Mark II) was initiated at Eagle-Picher Industries, Inc. and Gould, Inc. Work on stationary energy-storage batteries during this period has consisted primarily of conceptual design studies. 107 figures, 67 tables.

  18. Modification of the ultrasound induced activity by the presence of an electrode in a sonoreactor working at two low frequencies (20 and 40 kHz). Part I: Active zone visualization by laser tomography.

    PubMed

    Mandroyan, A; Viennet, R; Bailly, Y; Doche, M-L; Hihn, J-Y

    2009-01-01

    Sonoelectrochemical experiments differ from sonochemical ones by the introduction of electrodes in the sonicated reaction vessel. The aim of the study is to characterize the changes of the ultrasonic activity induced by the presence of an electrode located in front of the transducer. The scope of our investigations concerns two low frequencies vibration modes: 20 and 40 kHz. For this purpose, two laser visualization techniques have been used. The first part of the study, described in the present paper (part I), deals with the laser tomography technique which provides an accurate picture of the reactor actives zones, related to numerous cavitation events. For each frequency, two parameters were studied: the electrical power supplied to the transducer and the electrode transducer distance. At both frequencies, without electrode, we can observe distinct zones corresponding to cavitation production and stationary waves establishment. When increasing the input power, bubble clouds tend to form a unique cloud near the transducer. In presence of the electrode, bubble cavitation clouds are largely influenced by the obstacle. The second part of the paper (part II) will describe the Particle Image Velocimetry (P.I.V.) technique which allows to measure the velocity vector field in the fluid portion between the horn and the electrode.

  19. YAG laser-induced structural modification in transition metal ion containing 40K{sub 2}O-40Nb{sub 2}O{sub 5}-20SiO{sub 2} glasses

    SciTech Connect

    Venkataraman, B. Harihara; Komatsu, Takayuki

    2008-10-02

    Glasses with the compositions of 40K{sub 2}O-40Nb{sub 2}O{sub 5}-20SiO{sub 2} (in mol%) containing different concentrations (0.01, 1 and 2 mol%) of NiO were prepared by a melt quenching technique. The glasses were irradiated with a continuous wave Nd:YAG laser with a wavelength of 1064 nm, and a metastable crystalline phase of KNbO{sub 3} was obtained. In 2 mol% NiO-doped glass, lines with a width of {approx}10 {mu}m are successfully patterned by laser irradiations with a power of 0.9 W and a scanning speed of 15 {mu}m/s. It is found from micro-Raman scattering spectra that the lines are composed of the metastable crystalline phase of KNbO{sub 3}. The crystallization mechanism in Nd:YAG laser-induced crystallization in the glasses is discussed in comparison with the usual crystallization in an electric furnace.

  20. Development of advanced batteries at Argonne National Laboratory. Summary report for 1979. [Li-Al/LiCl-KCl/FeS or FeS/sub 2/, 40 kWh; also Ca-Si/FeS/sub 2/

    SciTech Connect

    1980-04-01

    A summary for 1979 of Argonne National Laboratory's program on the development of advanced batteries is presented. These batteries are being developed for electric-vehicle propulsion and stationary energy-storage applications. The principal cells under investigation at present are of a vertically oriented, prismatic design with one or more inner positive electrodes of FeS or FeS/sub 2/, facing negative electrodes of Li-Al alloy, and molten LiCl-KCl electrolyte; the cell operating temperature is 400 to 500/sup 0/C. A small effort on the development of a calcium/metal sulfide cell is also being conducted. During 1979, cell and battery development work continued at ANL and contractors' laboratories. A 40-kWh electric-vehicle battery (designated Mark IA) was fabricated and delivered by Eagle-Picher Industries, Inc. to ANL for testing. During heat-up, one of the modules failed due to a short circuit. A failure analysis was conducted, and the Mark IA program, completed. Development work on the next electric-vehicle battery (Mark II) was initiated at Eagle-Picher and Gould, Inc. Work on stationary energy-storage batteries consisted primarily of conceptual design studies. 9 figures, 7 tables.

  1. Agents that elevate the concentration of cAMP in platelets inhibits the formation of a NaDodSO/sub 4/-resistant complex between thrombin and a 40-kDa protein

    SciTech Connect

    Lerea, K.M.; Glomset, J.A.

    1987-08-01

    The authors studied the influence of prostaglandin E/sub 1/ and theophylline on the ability of rabbit or human platelets to form NaDodSO/sub 4/-resistant complexes between /sup 125/I-labeled thrombin and a platelet protein of approx. =40 kDa. Control platelets formed two types of these complexes, one that sedimented with the platelets and one that was found in the suspension medium. There were 30-40 sedimentable complexes per platelet and about three times this number of soluble complexes. Pretreatment of rabbit or human platelets with prostaglandin E/sub 1/ and theophylline decreased the formation of both types of complex by as much as 60-80%. The pretreatment was particularly effective when low doses of thrombin were used. When added to control platelets, such doses of thrombin caused the formation of sedimentable complexes and the concomitant formation of inositol trisphosphate. However, when added to platelets that had been pretreated with prostaglandin E/sub 1/ and theophylline, low doses of thrombin had little or no effect on either reaction.

  2. Isotopic studies of sources of uranium in sediments of the Ashtabula River, Ohio, U.S.A.

    SciTech Connect

    Ketterer, M.E.; Wetzel, W.C.; Layman, R.R.; Matisoff, G.; Bonniwell, E.C.

    2000-03-15

    Uranium contamination of anthropogenic origin has been identified in unconsolidated sediment of a 1.5 km portion of the Ashtabula River near its confluence with Lake Erie. Uranium concentrations as high as 188 {mu}g/g dry sediment are present. A small tributary of the Ashtabula River, Fields Brook, is the apparent point of origin of the uranium in the Ashtabula River sediments. {sup 137}Cs dating of a sediment core indicates that the U contamination occurred during the post-1964 time frame. The horizons of elevated U concentration also exhibit > 10x elevations in Zr, Nb, Hf, Ta, and W. {sup 238}U/{sup 235}U isotopic ratios indicate that the uranium is largely but not exclusively of natural composition. Distinct horizons of slightly {sup 235}U-depleted ({sup 238}U/{sup 235}U > 137.88) and slightly {sup 235}U-enriched ({sup 238}U/{sup 235}U < 137.88) uranium are also present. {sup 210}Pb activities and {sup 232}Th/{sup 230}Th isotopic measurements indicate that a significant portion of the uranium contains {sup 238}U daughters in approximate secular equilibrium. It is inferred that at least two distinct sources of anthropogenic U contamination exist: (a) discharges from the processing of enriched and depleted U metal by a DOE contractor facility and (B) U-bearing wastes from the production of TiO{sub 2} from limonite and associated minerals. These isotopic methodologies are potentially useful in settings where releases of nonnatural {sup 238}U/{sup 235}U composition materials and/or naturally occurring radioactive material (NORM) have taken place.

  3. Simultaneous {sup 233}U and{sup 235}U characterization through the assay of delayed neutron temporal behavior

    SciTech Connect

    Sellers, M. T.; Corcoran, E. C.; Kelly, D. G.

    2012-07-01

    Aqueous solutions containing dissolved uranium-233 and uranium-235 were irradiated for 60's in the SLOWPOKE-2 reactor at the Royal Military College of Canada. The temporal behavior of the delayed neutrons produced was recorded by the Facility's Delayed Neutron Counting (DNC) system. The percentage of uranium-233 as a function of total fissile mass present in each sample ranged from 0 to 100% and was predicted by the DNC system with average absolute errors of {+-} 4%. Future work will upgrade the system electronics and software to reduce both uncertainties in timings and electrical noise. Mixture analysis will also be expanded to include plutonium-239 and fissile materials contained in non-aqueous matrices. (authors)

  4. Evaluation of {sup 235}U, {sup 238}U, {sup 6}Li, and {sup 27}Al Cross Sections

    SciTech Connect

    Chandler, J.R.

    2001-05-17

    Good nuclear data are essential for accurate prediction of reactor parameters. Several cross section libraries are currently available for use with GLASS physics calculations. In recent Mark 15 and Mark 22 studies, cross section data were developed to provide more accurate buckling calculations for Mark 15 and Mark 22 charges. This report documents evaluation of these new data for universal application.

  5. The Current State of Genetics Training in Psychiatric Residency: Views of 235 U.S. Educators and Trainees

    ERIC Educational Resources Information Center

    Hoop, Jinger G.; Savla, Gauri; Roberts, Laura Weiss; Zisook, Sidney; Dunn, Laura B.

    2010-01-01

    Objective: As researchers make progress in understanding genetic aspects of mental illness and its treatment, psychiatrists will increasingly need to understand and interpret genetic information specific to psychiatric disorders. Little is known about the extent to which residency programs are preparing psychiatrists for this new role. This study…

  6. Commissioning the NIFFTE Time Projection Chamber: Towards the 238U / 235U (n, f) Cross-section Ratio

    NASA Astrophysics Data System (ADS)

    Meharchand, R.; Asner, D. M.; Baker, R. G.; Bundgaard, J.; Burgett, E.; Cunningham, M.; Deaven, J.; Duke, D. L.; Greife, U.; Grimes, S.; Heffner, M.; Hill, T.; Isenhower, D.; Klay, J. L.; Kleinrath, V.; Kornilov, N.; Laptev, A. B.; Loveland, W.; Massey, T. N.; Qu, H.; Ruz, J.; Sangiorgio, S.; Seilhan, B.; Snyder, L.; Stave, S.; Tatishvili, G.; Thornton, R. T.; Tovesson, F.; Towell, D.; Towell, R. S.; Watson, S.; Wendt, B.; Wood, L.

    2014-05-01

    The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) collaboration is developing a Time Projection Chamber (TPC) to measure neutron-induced fission cross sections with unprecedented accuracy. Modifying TPC technology for nuclear physics applications is a challenging endeavor, and frequent testing and evaluation is required to ensure that all components are behaving as expected. In-beam tests of the NIFFTE TPC at the Los Alamos Neutron Science Center (LAN-SCE) commenced in 2010. An overview of the NIFFTE TPC experiments performed at LANSCE will be presented, along with preliminary performance results.

  7. Determination of the 235U Mass and Enrichment within Small UF6 Cylinders via a Neutron Coincidence Well Counting System

    SciTech Connect

    McElroy, Robert Dennis; Croft, Dr. Stephen; Young, Brian M; Venkataraman, Ram

    2011-01-01

    The construction of three new uranium enrichment facilities in the United States has sparked renewed interest in the development and enhancement of methods to determine the enrichment and fissile mass content of UF6 cylinders. We describe the design and examine the expected performance of a UF6 bottle counter developed for the assay of Type 5A cylinders. The counter, as designed and subsequently constructed, is a tall passive neutron well counter with a clam-shell configuration and graphite end plugs operated in fast neutron mode. Factory performance against expectation is described. The relatively high detection efficiency and effectively 4 detection geometry provide a near-ideal measurement configuration, making the UF6 bottle counter a valuable tool for the evaluation of the neutron coincidence approach to UF6 cylinder assay. The impacts of non-uniform filling, voids, enrichment, and mixed enrichments are examined

  8. Radioisotopes (137Cs, 40K, 210Pb) indicate that cryoturbation processes in Alaskan tussock tundra are accelerated under deeper winter snow: results from short and long-term winter snow depth experiments

    NASA Astrophysics Data System (ADS)

    Blanc-Betes, E.; Sturchio, N. C.; Taneva, L.; Welker, J. M.; Guilderson, T. P.; Poghosyan, A.; Gonzalez-Meler, M. A.

    2010-12-01

    Permafrost soils cover 8.6% of the Earth land area and contain up to 50% of the global soil organic carbon (SOC) pool. Amplified warming in northern latitudes has resulted directly and/or indirectly in multiple structural and functional changes in arctic ecosystems which may lead to strong forcing feedbacks on the climate system. Cryoturbation is a dominant soil forming process in permafrost regions that results to the mixing of soil layers during freeze-thaw cycles, and may increase in rates following global warming. As a result, the active layer of cryoturbated soils can average 62% larger C stocks than those from non-cryoturbated ones. Cryoturbation is a critical overlooked driver of C dynamics in permafrost soils that will likely play a pivotal role in the fate of Arctic soil C under climate change conditions. However, cryoturbation phenomena is difficult to quantify. We measured cryoturbation rates using a multiple isotope approach at Toolik Lake, Alaska, in moist acidic tundra soils from short- and long-term snow addition experiments. Shifts in cryoturbation rates as affected by these manipulations were measured by the relative activity of natural and weapon-derived radioisotopes (e.g. 137Cs, 40K, 210Pb). By tracking the vertical distribution of these fallout and natural radioisotopes in soils and calculating soil diffusion coefficients, we were able to quantify cryoturbation mixing rates and sediment transport mechanisms that operate at multiannual time scales. Our results show an apparent uplift of buried organic matter to the surface as a result of soil thermal insulation and subsequent deepening of the active layer. These results sharply contrast with current notions that cryoturbation in Arctic systems results in net burial of organic matter, resulting in increased C storage at depth. Mechanisms of this mechanical mixing and its effects on C redistribution and storage of organic matter will be presented to shed light on this apparent contradiction.

  9. Preliminary Results on Direct Observation of True Ternary fission in the reaction {sup 232}Th+d (10 MeV)

    SciTech Connect

    Pyatkov, Yu.; Kamanin, D.; Alexandrov, A.; Alexandrova, I.; Kondratyev, N.; Kuznetsova, E.; Tyukavkin, A.; Zhuchko, V.; Krasznohorkay, A.; Csatlos, M.; Csige, L.; Gulyas, J.; Naqvi, F.; Tornyi, T.

    2010-04-30

    Results of the first direct observation of the true ternary fission of {sup 234}Pa* nucleus are presented. The yield of the effect depending of the experimental geometry is about 10{sup -5}/binary fission. Mass of the lightest fragment in the triplet lies mainly in the range of (20 divide 40) a.m.u. Connection between the effect and known heavy ion or lead radioactivity is discussed.

  10. Clay Mineral: Radiological Characterization

    NASA Astrophysics Data System (ADS)

    Cotomácio, J. G.; Silva, P. S. C.; Mazzilli, B. P.

    2008-08-01

    Since the early days, clays have been used for therapeutic purposes. Nowadays, most minerals applied as anti-inflammatory, pharmaceutics and cosmetic are the clay minerals that are used as the active ingredient or, as the excipient, in formulations. Although their large use, few information is available in literature on the content of the radionuclide concentrations of uranium and thorium natural series and 40K in these clay minerals. The objective of this work is to determine the concentrations of 238U, 232Th, 226Ra, 228Ra, 210Pb and 40K in commercial samples of clay minerals used for pharmaceutical or cosmetic purposes. Two kinds of clays samples were obtained in pharmacies, named green clay and white clay. Measurement for the determination of 238U and 232Th activity concentration was made by alpha spectrometry and gamma spectrometry was used for 226Ra, 228Ra, 210Pb and 40K determination. Some physical-chemical parameters were also determined as organic carbon and pH. The average activity concentration obtained was 906±340 Bq kg-1 for 40K, 40±9 Bq kg-1 for 226Ra, 75±9 Bq kg-1 for 228Ra, 197±38 Bq kg-1 for 210Pb, 51±26 Bq kg-1 for 238U and 55±24 Bq kg-1 for 232Th, considering both kinds of clay.

  11. Temporal limits on the habitability of rocky worlds

    NASA Astrophysics Data System (ADS)

    Frank, Elizabeth Anne

    The epoch of habitability on a rocky world is dictated by the suite of geological events and processes it experiences. A planet may be habitable for a long stretch of its history, but that period has limits. When is too soon for life to arise on a planet, and when is it too late for it to continue? Limits for habitability on Earth-like planets can be defined by extracting Earth's history from the geochemical record to infer that of the rocky planets lying far beyond the reaches of our solar system. The Late Veneer was the last recorded impact event capable of melting the Earth's crust---and extinguishing any extant life. Eoarchean ultramafic schists (metakomatiites) from Greenland and Canada show highly siderophile element depletions consistent with a deep mantle that had yet to be fully contaminated by Late Veneer material. Whether it was one impactor or multiple, it is clear that the iteration of life from which we originate must have arisen no earlier than the Late Veneer. Planetary accretion stymies the emergence of life, but geophysics might provide its eventual demise. Plate tectonics operates on Earth as a globate climate moderator, keeping Earth's surface temperate. Geological activity is maintained largely by the long-lived, heat-producing radionuclides 40K, 232Th, 235U, and 238U, whose concentrations decline as Earth ages. Eventually, these isotopes will no longer be able to provide the heat required for mantle convection, and plate tectonics will shut down, calling into question Earth's ability to maintain habitability on a global scale. Here, the Late Veneer is proposed for the first time as a hard constraint for when life could have arisen on Earth, and age is shown to be a key player in the long-term thermal regimes of conventionally defined Earth-like exoplanets. Provided with limits on the reign of life on Earth, the habitability of rocky exoplanets can be evaluated: those that are too young will still be experiencing surface-sterilizing impact

  12. Radiation Doses to Members of the U.S. Population from Ubiquitous Radionuclides in the Body: Part 3, Results, Variability, and Uncertainty

    SciTech Connect

    Watson, David J.; Strom, Daniel J.

    2011-02-25

    This paper is part three of a three-part series investigating annual effective doses to residents of the United States from intakes of ubiquitous radionuclides, including radionuclides occurring naturally, radionuclides whose concentrations are technologically enhanced, and anthropogenic radionuclides. The radionuclides of interest are the 238U series (14 nuclides), the actinium series (headed by 235U; 11 nuclides), and the 232Th series (11 nuclides); primordial radionuclides 87Rb and 40K; cosmogenic and fallout radionuclides 14C and 3H; and purely anthropogenic radionuclides 137Cs-137mBa, 129I and 90Sr-90Y. This series of papers explicitly excludes intakes from inhaling 222Rn, 220Rn, and their short-lived decay products; it also excludes intakes of radionuclides in occupational and medical settings. Part one reviewed, summarized, characterized, and grouped all published and some unpublished data for U.S. residents on ubiquitous radionuclide concentrations in tissues and organs. Part two described the methods used to organize the data collected in part one and segregate it into the ages and genders defined by the study, imputed missing values from the existing data, apportioned activity in bone, and imputed activity in hollow organ contents and the remainder of the body. This paper estimates equivalent doses to target tissues from source regions and maps target tissues to lists of tissues with International Commission on Radiation Protection (ICRP) tissue-weighting factors or to surrogate tissue regions when there is no direct match. Effective doses, using ICRP tissue-weighting factors recommended in 1977, 1990, and 2007, are then calculated, and an upper bound of variability of the effective dose is estimated by calculating the average coefficients of variation (CV), assuming all variance is due to variability. Most of the data were for adult males, whose average annual effective dose is estimated to be 337 μSv (CV = 0.65, geometric mean = 283 μSv, geometric

  13. Natural radioactivity concentration of peanuts in Osmaniye-Turkey

    SciTech Connect

    Akkurt, Iskender; Guenoglu, Kadir; Mavi, Betuel; Kara, Ayhan

    2012-09-06

    The peanut is grown in Osmaniye where located in southern Turkey. Due to it is grown underground, the measurements of natural radioactivity of peanuts become important. For this reason some peanut samples have been collected from different places of Osmaniye and the measurements of natural activity concentrations for {sup 40}K, {sup 226}Ra and {sup 232}Th in some peanuts samples have been carried out using a NaI(Tl) gamma-ray spectrometer. Activity of {sup 40}K was measured from its intensive line at 1460 keV, for {sup 226}Ra activity peak from {sup 214}Bi at 1760 keV and {sup 232}Th activity, peak from {sup 208}Tl at energy of 2610 keV was used.

  14. Assessment of radiation hazards due to natural radioactivity in some building materials used in Egyptian dwellings.

    PubMed

    Medhat, M E

    2009-02-01

    Different types of Egyptian building materials from various locations in Cairo and its suburbs have been analysed for natural radioactivity using gamma ray spectrometry. Concentrations of (226)Ra, (232)Th and (40)K were in the ranges of (12 +/- 2.8-65 +/- 6.5), (5 +/- 1.8-60 +/- 6.7) and (159 +/- 3.8-920 +/- 12.7 Bq kg(-1)), respectively. The minimum concentration of (226)Ra, (232)Th and (40)K was found in gravel samples, whereas the maximum in granite samples. The results are compared with the published data of other countries and with the world average limits. The radiological hazard parameters: radium equivalent activity, gamma index, alpha index, absorbed dose rate and the annual exposure rate, were determined to assess the radiation hazards associated with Egyptian buildings. All studied samples are lower than world average limits.

  15. Assessment of indoor absorbed gamma dose rate from natural radionuclides in concrete by the method of build-up factors.

    PubMed

    Manić, Vesna; Nikezic, Dragoslav; Krstic, Dragana; Manić, Goran

    2014-12-01

    The specific absorbed gamma dose rates, originating from natural radionuclides in concrete, were calculated at different positions of a detection point inside the standard room, as well as inside an example room. The specific absorbed dose rates corresponding to a wall with arbitrary dimensions and thickness were also evaluated, and appropriate fitting functions were developed, enabling dose rate calculation for most realistic rooms. In order to make calculation simpler, the expressions fitting the exposure build-up factors for whole (238)U and (232)Th radionuclide series and (40)K were derived in this work, as well as the specific absorbed dose rates from a point source in concrete. Calculated values of the specific absorbed dose rates at the centre point of the standard room for (238)U, (232)Th and (40)K are in the ranges of previously obtained data.

  16. Mussels (Mytilus galloprovincialis) as a bio-indicator species in radioactivity monitoring of Eastern Adriatic coastal waters.

    PubMed

    Krmpotić, Matea; Rožmarić, Martina; Barišić, Delko

    2015-06-01

    Croatian Adriatic coastal waters are systematically monitored within the Mediterranean Mussel Watch Project using mussels (Mytilus galloprovincialis) as a bio-indicator species. The study includes determination of naturally occurring ((7)Be, (40)K, (232)Th, (226)Ra and (238)U), as well as anthropogenic (137)Cs radionuclides. Activity concentrations in dry weight of mussels' soft tissue along the Croatian Adriatic coast are presented, with spatial and seasonal variations given and discussed. Samples were collected in spring and autumn for the period between 2009 and 2013. Radionuclides were determined by gamma-ray spectrometry. Activity concentrations of (7)Be were the highest in spring periods, especially in the areas with significant fresh water discharges. Activity concentrations of (40)K did not vary significantly with season or location. (137)Cs activities were low, while (232)Th, (226)Ra and (238)U activities were mostly below the detection limit of performed gamma-spectrometric measurement.

  17. Mussels (Mytilus galloprovincialis) as a bio-indicator species in radioactivity monitoring of Eastern Adriatic coastal waters.

    PubMed

    Krmpotić, Matea; Rožmarić, Martina; Barišić, Delko

    2015-06-01

    Croatian Adriatic coastal waters are systematically monitored within the Mediterranean Mussel Watch Project using mussels (Mytilus galloprovincialis) as a bio-indicator species. The study includes determination of naturally occurring ((7)Be, (40)K, (232)Th, (226)Ra and (238)U), as well as anthropogenic (137)Cs radionuclides. Activity concentrations in dry weight of mussels' soft tissue along the Croatian Adriatic coast are presented, with spatial and seasonal variations given and discussed. Samples were collected in spring and autumn for the period between 2009 and 2013. Radionuclides were determined by gamma-ray spectrometry. Activity concentrations of (7)Be were the highest in spring periods, especially in the areas with significant fresh water discharges. Activity concentrations of (40)K did not vary significantly with season or location. (137)Cs activities were low, while (232)Th, (226)Ra and (238)U activities were mostly below the detection limit of performed gamma-spectrometric measurement. PMID:25794925

  18. Soudan Low Background Counting Facility (SOLO)

    SciTech Connect

    Attisha, Michael; Viveiros, Luiz de; Gaitksell, Richard; Thompson, John-Paul

    2005-09-08

    The Soudan Low Background Counting Facility (SOLO) has been in operation at the Soudan Mine, MN since March 2003. In the past two years, we have gamma-screened samples for the Majorana, CDMS and XENON experiments. With individual sample exposure times of up to two weeks we have measured sample contamination down to the 0.1 ppb level for 238U / 232Th, and down to the 0.25 ppm level for 40K.

  19. Distribution of natural and artificial radioactivity in soils, water and tuber crops.

    PubMed

    Darko, Godfred; Faanu, Augustine; Akoto, Osei; Acheampong, Akwasi; Goode, Eric Jude; Gyamfi, Opoku

    2015-06-01

    Activity concentrations of radionuclides in water, soil and tuber crops of a major food-producing area in Ghana were investigated. The average gross alpha and beta activities were 0.021 and 0.094 Bq/L, respectively, and are below the guidelines for drinking water and therefore not expected to pose any significant health risk. The average annual effective dose due to ingestion of radionuclide in water ranged from 20.08 to 53.45 μSv/year. The average activity concentration of (238)U, (232)Th, (40)K and (137)Cs in the soil from different farmlands in the study area was 23.19, 31.10, 143.78 and 2.88 Bq/kg, respectively, which is lower than world averages. The determined absorbed dose rate for the farmlands ranged from 23.63 to 50.51 nGy/year, which is within worldwide range of 18 to 93 nGy/year. The activity concentration of (238)U, (232)Th, (40)K and (137)Cs in cassava ranges from 0.38 to 6.73, 1.82 to 10.32, 17.65 to 41.01 and 0.38 to 1.02 Bq/kg, respectively. Additionally, the activity concentration of (238)U, (232)Th, (40)K and (137)Cs in yam also ranges from 0.47 to 4.89, 0.93 to 5.03, 14.19 to 35.07 and 0.34 to 0.89 Bq/kg, respectively. The average concentration ratio for (238)U, (232)Th and (40)K in yam was 0.12, 0.11 and 0.17, respectively, and in cassava was 0.11, 0.12 and 0.2, respectively. None of the radioactivity is expected to cause significant health problems to human beings.

  20. Natural radioactive nuclides and chemical components in the groundwater of Beni Suef Governate, Middle Egypt.

    PubMed

    Khalil, F A; Amin, Rafat M; El Fayoumi, M A K

    2009-03-01

    Measurements of natural radioactivity in drinking water have been performed in many parts of the world, mostly for assessment of the doses and risk resulting from consuming water. A study of the radionuclide and chemical components in groundwater from Beni Suef Governate, Egypt has been carried out. Fifty water samples were analysed by gamma-ray spectroscopy to determine the (226)Ra, (232)Th and (40)K concentrations; major elements, pH, alkalinity and conductivity were also measured. The activity concentration values ranged from 0.008 to 0.040 Bq l(-1) for (226)Ra, from 0.003 to 0.019 Bq l(-1) for (232)Th and from 0.025 to 0.344 Bq l(-1) for (40)K. The annual ingestion of these radionuclides, using local consumption rates (averaged over the whole population) of 1.5 l d(-1), was estimated to be 8.59, 4.86 and 83.47 Bq y(-1) for (226)Ra, (232)Th and (40)K, respectively. The estimated effective doses from drinking water were found to be 2.4 microSv y(-1) ((226)Ra), 1.1 microSv y(-1) ((232)Th) and 0.5 microSv y(-1) ((40)K). The contribution of these radionuclides to the committed effective dose from a year's consumption of drinking water is therefore estimated to be only 4% of the WHO value (0.1 mSv y(-1)). The moderate pH value is the most important parameter, and there was no observed correlation between natural radioactivity and electrical conductivity or concentrations of major ions.

  1. Activity concentrations and dose rates from decorative granite countertops.

    PubMed

    Llope, W J

    2011-06-01

    The gamma radiation emitted from a variety of commercial decorative granites available for use in U.S. homes has been measured with portable survey meters as well as an NaI(Th) gamma spectrometer. The (40)K, U-nat, and (232)Th activity concentrations were determined using a full-spectrum analysis. The dose rates that would result from two different arrangements of decorative granite slabs as countertops were explored in simulations involving an adult anthropomorphic phantom.

  2. Preliminary survey of outdoor gamma dose rates in Lesvos Island (Greece).

    PubMed

    Petalas, Anastasios B; Vogiannis, Efstratios; Nikolopoulos, Dimitrios; Halvadakis, Constantinos P

    2005-01-01

    This study reports the first attempt to record the radioactive background due to gamma radiation in Lesvos Island (Greece). The study reports the results from 335 outdoor total gamma effective dose rate measurements conducted using GPS navigation and a Geiger-Muller detector (Bicron, Micro Sievert) on the whole surface of the island together with a digital map produced by appropriate mapping GIS programme. The study also reports the measurements of outdoor gamma dose rates due to the 238U, 232Th and 40K radionuclides as estimated via in situ gamma-ray spectrometry measurements performed at 26 sites using a 3 x 3 inch NaI (thallium activated) portable detector. The results from the outdoor total gamma effective dose rates range between 0.0023 and 0.28 microSv h(-1). The highest outdoor total gamma effective dose rates (0.013-0.28 microSv h(-1)) were detected in the northeastern part of the island and the intermediate rates (0.066-0.13 microSv h(-1)) in the central region. The outdoor gamma dose rates due to 238U, 232Th and 40K radionuclides range between 1.7 +/- 0.8 and 154 +/- 7 nGy h(-1) with an average of 86 +/- 6 nGy h(-1). The average contribution of each of the examined radionuclides (238U, 232Th and 40K) to the total gamma dose rate was found to be equal to 12 +/- 4% for 238U, 58 +/- 6% for 232Th and 29 +/- 7% for 40K, respectively. PMID:15728423

  3. Measurement of radioactivity levels in soil in the Nile Delta and middle Egypt.

    PubMed

    Ibrahiem, N M; Abd el Ghani, A H; Shawky, S M; Ashraf, E M; Farouk, M A

    1993-06-01

    Concentrations of radionuclides in surface soil across the Nile Delta, the north coast of Egypt, and Middle Egypt have been measured using a hyperpure germanium spectrometer. The concentrations obtained for 40K, the 232Th series, and the 226Ra series are expressed in Bq kg-1 of dry weight, and the exposure rates are expressed in nGy h-1 of wet weight. The activity concentrations of 137Cs in soil are expressed in Bq m-2.

  4. Assessments of radioactivity concentration of natural radionuclides and radiological hazard indices in sediment samples from the East coast of Tamilnadu, India with statistical approach.

    PubMed

    Ravisankar, R; Chandramohan, J; Chandrasekaran, A; Prince Prakash Jebakumar, J; Vijayalakshmi, I; Vijayagopal, P; Venkatraman, B

    2015-08-15

    This paper reports on the distribution of three natural radionuclides (238)U, (232)Th and (40)K in coastal sediments from Pattipulam to Devanampattinam along the East coast of Tamilnadu to establish baseline data for future environmental monitoring. Sediment samples were collected by a Peterson grab samples from 10m water depth parallel to the shore line. Concentration of natural radionuclides were determined using a NaI(Tl) detector based γ-spectrometry. The mean activity concentration is ⩽2.21, 14.29 and 360.23Bqkg(-1) for (238)U, (232)Th and (40)K, respectively. The average activity of (232)Th, (238)U and (40)K is lower when compared to the world average value. Radiological hazard parameters were estimated based on the activity concentrations of (238)U, (232)Th and (40)K to find out any radiation hazard associated with the sediments. The radiological hazard parameters such as radium equivalent activity (Raeq), absorbed gamma dose rates in air (DR), the annual gonadal dose equivalent (AGDE), annual effective dose equivalent (AEDE), external hazard index (Hex) internal hazard index (Hin), activity utilization index (AUI) and excess lifetime cancer (ELCR) associated with the radionuclides were calculated and compared with internationally approved values and the recommended safety limits. Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied in order to recognize and classify radiological parameters in sediments collected at 22 sites on East coast of Tamilnadu. The values of radiation hazard parameters were comparable to the world averages and below the recommended values. Therefore, coastal sediments do not to pose any significant radiological health risk to the people living in nearby areas along East coast of Tamilnadu. The data obtained in this study will serve as a baseline data in natural radionuclide concentration in sediments along the coastal East coast of Tamilnadu.

  5. Assessments of radioactivity concentration of natural radionuclides and radiological hazard indices in sediment samples from the East coast of Tamilnadu, India with statistical approach.

    PubMed

    Ravisankar, R; Chandramohan, J; Chandrasekaran, A; Prince Prakash Jebakumar, J; Vijayalakshmi, I; Vijayagopal, P; Venkatraman, B

    2015-08-15

    This paper reports on the distribution of three natural radionuclides (238)U, (232)Th and (40)K in coastal sediments from Pattipulam to Devanampattinam along the East coast of Tamilnadu to establish baseline data for future environmental monitoring. Sediment samples were collected by a Peterson grab samples from 10m water depth parallel to the shore line. Concentration of natural radionuclides were determined using a NaI(Tl) detector based γ-spectrometry. The mean activity concentration is ⩽2.21, 14.29 and 360.23Bqkg(-1) for (238)U, (232)Th and (40)K, respectively. The average activity of (232)Th, (238)U and (40)K is lower when compared to the world average value. Radiological hazard parameters were estimated based on the activity concentrations of (238)U, (232)Th and (40)K to find out any radiation hazard associated with the sediments. The radiological hazard parameters such as radium equivalent activity (Raeq), absorbed gamma dose rates in air (DR), the annual gonadal dose equivalent (AGDE), annual effective dose equivalent (AEDE), external hazard index (Hex) internal hazard index (Hin), activity utilization index (AUI) and excess lifetime cancer (ELCR) associated with the radionuclides were calculated and compared with internationally approved values and the recommended safety limits. Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied in order to recognize and classify radiological parameters in sediments collected at 22 sites on East coast of Tamilnadu. The values of radiation hazard parameters were comparable to the world averages and below the recommended values. Therefore, coastal sediments do not to pose any significant radiological health risk to the people living in nearby areas along East coast of Tamilnadu. The data obtained in this study will serve as a baseline data in natural radionuclide concentration in sediments along the coastal East coast of Tamilnadu. PMID:26036177

  6. Natural radioactivity measurements in Pahang State, Malaysia.

    PubMed

    Gabdo, Hamman Tukur; Ramli, Ahmad Termizi; Saleh, Muneer Aziz; Garba, Nuraddeen Nasiru; Sanusi, Mohamad

    2016-06-01

    This study was aimed at providing the baseline data of terrestrial gamma dose rates and natural radioactivity to assess the corresponding health risk in the ambient environment of the Pahang State. Terrestrial gamma radiation (TGR) from 640 locations was measured with the mean value found to be 176 ± 5 nGy h(-1). Ninety-eight soil samples were analysed using a high-purity germanium detector (HPGe), and the mean concentrations of the radionuclides (226)Ra, (232)Th and (40)K are 110 ± 3, 151 ± 5 and 542 ± 51 Bq kg(-1), respectively.(226)Ra and (232)Th concentrations were found to be three times the world average, while that of (40)K is quite higher than the world average value. The acid-intrusive geological formation has the highest mean concentrations for (226)Ra (215 ± 6 Bq kg(-1)), (232)Th (384 ± 12 Bq kg(-1)) and (40)K (1564 ± 153 Bq kg(-1)). The radium equivalent activities (Req) and the external hazard index (Hex) for the various soil types were also calculated. Some of the soil types were found to have values exceeding the internationally recommended levels of 370 Bq kg(-1) and the unity value, respectively.

  7. A radiological survey of the Eğrigöz granitoid, Western Anatolia/Turkey.

    PubMed

    Canbaz Öztürk, B; Yaprak, G; Çam, N F; Candan, O

    2015-06-01

    A radiological survey of the granitoid areas throughout Western Anatolia was conducted during 2007-14. As a part of this radiological survey, this article presents results obtained from Eğrigöz pluton, which lies in the northeastern region of Western Anatolia. In the investigated area, the activity measurements of the natural gamma-emitting radionuclides ((226)Ra, (232)Th and (40)K) in the granitic rock samples and soils have been carried out by means of the NaI(Tl) gamma-ray spectrometry system. The activity concentrations of the relevant natural radionuclides in the granite samples appeared in the ranges as follows: (226)Ra, 28-95 Bq kg(-1); (232)Th, 50-122 Bq kg(-1) and (40)K, 782-1365 Bq kg(-1), while the typical ranges of the (226)Ra, (232)Th and (40)K activities in the soil samples were found to be 7-184, 11-174 and 149-1622 Bq kg(-1), respectively. Based on the available data, the radiation hazard parameters associated with the surveyed rocks/soils are calculated. The corresponding absorbed dose rates in air from all those radionuclides were always much lower than 200 nGy h(-1) and did not exceed the typical range of worldwide average values noted in the UNSCEAR (2000) report. Furthermore, the data are also used for the mapping of the surface soil activity of natural radionuclides and the corresponding gamma dose rates of the surveyed area. PMID:25979749

  8. A radiological survey of the Eğrigöz granitoid, Western Anatolia/Turkey.

    PubMed

    Canbaz Öztürk, B; Yaprak, G; Çam, N F; Candan, O

    2015-06-01

    A radiological survey of the granitoid areas throughout Western Anatolia was conducted during 2007-14. As a part of this radiological survey, this article presents results obtained from Eğrigöz pluton, which lies in the northeastern region of Western Anatolia. In the investigated area, the activity measurements of the natural gamma-emitting radionuclides ((226)Ra, (232)Th and (40)K) in the granitic rock samples and soils have been carried out by means of the NaI(Tl) gamma-ray spectrometry system. The activity concentrations of the relevant natural radionuclides in the granite samples appeared in the ranges as follows: (226)Ra, 28-95 Bq kg(-1); (232)Th, 50-122 Bq kg(-1) and (40)K, 782-1365 Bq kg(-1), while the typical ranges of the (226)Ra, (232)Th and (40)K activities in the soil samples were found to be 7-184, 11-174 and 149-1622 Bq kg(-1), respectively. Based on the available data, the radiation hazard parameters associated with the surveyed rocks/soils are calculated. The corresponding absorbed dose rates in air from all those radionuclides were always much lower than 200 nGy h(-1) and did not exceed the typical range of worldwide average values noted in the UNSCEAR (2000) report. Furthermore, the data are also used for the mapping of the surface soil activity of natural radionuclides and the corresponding gamma dose rates of the surveyed area.

  9. Determination of uranium, thorium and potassium activity concentrations in soil cores in Araba valley, Jordan.

    PubMed

    Abusini, M; Al-Ayasreh, K; Al-Jundi, J

    2008-01-01

    Soil samples were collected from six different locations in Araba valley, situated between Aqaba port and Dead sea. The samples have been analysed by using gamma-ray spectrometry. From the measured gamma-ray spectra, activity concentrations are determined for (238)U, (232)Th and (40)K. The mean activity concentration for (238)U, (232)Th and (40)K was found to be in the range 19 +/- 1.4 to 38.7 +/- 3, 14.3 +/- 0.8 to 35 +/- 3.2 and 94 +/- 18.9 to 762 +/- 47.4 Bq kg(-1), respectively. These results indicate that the mean concentrations of (238)U, (232)Th and (40)K in the populated Araba valley are lower than those in other populated areas. On the other hand, the concentrations of the major oxides (Al(2)O(3), SiO(2), K(2)O, CaO and Fe(2)O(3)) in the samples were determined using wavelength dispersive X-ray fluorescence. High potassium and iron content in some samples might be attributed to the active faults, which refer to the Dead sea transform fault.

  10. Natural radionuclide uptake by mosses in eastern Serbia in 2008-2013.

    PubMed

    Čučulović, Ana Č; Sabovljević, Marko; Čučulović, Rodoljub Č; Veselinović, Dragan

    2016-03-01

    The results of the study on natural radionuclide content in 102 samples of the moss species randomly collected in 2008- 2013 at 30 locations of eastern Serbia are presented in the paper. The activity concentration values of 238U, 226Ra, 232Th, 40K, and 7Be determined by gamma spectrometry were within the intervals: 238U (1.1-50) Bq kg(-1), 226Ra (1.1-41) Bq kg(-1), 232Th (1.4-28) Bq kg(-1), 40K (64-484) Bq kg(-1) and 7Be (88-227) Bq kg(-1), not standing out of the average data reported for this region. The distribution of the obtained data for 226Ra, 232Th, and 238U activity concentration in the analysed mosses has shown values up to 10 Bq kg(-1) with frequencies 47.1 %, 54.9 % and 48.0 %, respectively. The obtained activity concentration values of primordial 40K and cosmogenic radionuclide 7Be were up to 500 Bq kg(-1) and about 90 % of all the results for 7Be uptake by mosses were in the 200-250 Bq kg(-1) concentration range. PMID:27092637

  11. Radioactivity levels in plant samples in Tulkarem district, Palestine and its impact on human health.

    PubMed

    Thabayneh, Kaleel M; Jazzar, Mohannad M

    2013-01-01

    The activity concentrations of naturally occurring radioactive materials such as (226)Ra, (238)U, (232)Th, (40)K and (137)Cs were measured for 44 plant samples collected from different locations in the northwestern region of the West Bank, Palestine, using high-resolution gamma ray spectroscopy. The activity concentrations of radionuclides in the investigated plant samples ranged from 7.5 to 157.6 Bq kg(-1) for (226)Ra, 7.5 to 66.1 Bq kg(-1) for (238)U, 1.8 to 48.5 Bq kg(-1) for (232)Th, 14.3 to 1622 Bq kg(-1) for (40)K and <0.1 to 4.7 Bq kg(-1) for (137)Cs. The average values of these activities were 48.3, 26.5, 10.1, 288.0 and 2.2 Bq kg(-1), for (226)Ra, (238)U, (232)Th, (40)K and (137)Cs, respectively. The study presents the total gamma radiation dose rate assessed from natural radionuclides,(137)Cs and cosmic radiation, the dose rate of each radionuclide and the effective dose for all the samples. The radiological health implication to the population that may result from these doses is found to be low, except in few cases. The measurements have been taken as representing a baseline database of values of these radionuclides in the plants in the area. PMID:22798274

  12. An evaluation of the natural radioactivity in Andaman beach sand samples of Thailand after the 2004 tsunami.

    PubMed

    Malain, D; Regan, P H; Bradley, D A; Matthews, M; Al-Sulaiti, H A; Santawamaitre, T

    2012-08-01

    Following the 2004 'Boxing day' tsunami, a determination has been made of the activity concentrations of (226)Ra, (232)Th and (40)K in beach sand samples which have been collected from various locations along the Andaman coast of the Thai peninsula. Use has been made of a HPGe detector-based, low-background gamma-ray counting system. The natural radioactivity levels of (226)Ra, (232)Th and (40)K measured from these samples was found to lie in the range 1.6-52.5, 0.3-73.9 and 2.8-1111.9Bq/kg respectively for the west coast and 3.5-83.1, 4.5-42.0, and 9.6-1376 Bq/kg respectively for the east coast. The radioactivity concentrations of (226)Ra, (232)Th and (40)K along the Andaman coast are comparable to that of the east coast, which was not exposed to the tsunami. The corresponding annual effective dose varies from 1.6-105.9 μSv/y with a mean value of 59.1 ± 0.3 μSv/y, significantly lower than the worldwide average as reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) (2000).

  13. Distribution of natural radionuclides in soils and beach sands of Abana-Çatalzeytin (Kastamonu)

    NASA Astrophysics Data System (ADS)

    Kurnaz, Aslı; Özcan, Murat; ćetiner, M. Atıf

    2016-03-01

    A gamma spectrometric study of distribution of natural radionuclides in soil and beach sand samples collected from the terrestrial and coastal environment of Abana and Çatalzeytin counties of Kastamonu Province in Turkey was performed with the aim of estimating the radiation hazard of the tourist area and the concentrations of 238U, 232Th and 40K were determined. The activity concentrations of 238U, 232Th and 40K were determined in the ranges 14.95-56.0, 46.5-99.4 and 357.5-871.3 Bqkg-1 for soil samples and the mean concentrations were ascertained as 42.34, 71.24 and 624.18 Bqkg-1, respectively. In sand samples, 238U, 232Th and 40K contents were varied in the ranges of 13.35-41.6, 30.9-53.4 and 275.5-601.3 Bqkg-1 and the mean concentrations were ascertained as 20.57, 45.05 and 411.71 Bqkg-1, respectively. The mean annual effective doses were calculated as 113.08 and 69.16 µSvy-1 for the soil and sand samples, respectively.

  14. Natural radioactivity and associated dose rates in soil samples from Kalpakkam, South India.

    PubMed

    Sowmya, M; Senthilkumar, B; Seshan, B R R; Hariharan, G; Purvaja, R; Ramkumar, S; Ramesh, R

    2010-10-01

    The activity concentration of naturally occurring radioactive elements such as 226Ra, 232Th and 40K were measured for 46 soil samples collected in the vicinity of the Madras atomic power station, Kalpakkam, South India using gamma-ray spectroscopy. The average activity concentration of 226Ra, 232Th and 40K in soil samples were found to be 22.6 ± 12.6, 92.8 ± 44.3 and 434.1 ± 131.1 Bq kg(-1), respectively. The activity concentration of natural radionuclides is higher than the world average except for (226)Ra. The external absorbed gamma dose rates due to 226Ra, 232Th and 40K are observed to be 74.6 ± 30.8 nGy h(-1) with a corresponding annual effective dose of 91.5 ± 37.8 µSv y(-1), which are also above the world average. The values of radium equivalent activity and external hazard index are less than the world average. Whereas, the values of the radioactivity level index (I(γ)) and the total gamma dose rate were found to be above the required criterion. PMID:20522563

  15. Natural radionuclide activities in forest soil horizons of Mount IDA/Kazdagi, Turkey.

    PubMed

    Karadeniz, Özlem; Karakurt, Hidayet; Akal, Cüneyt

    2015-06-01

    Natural radioactivity distribution of (40)K, (238)U, and (232)Th isotopes in forest soils was investigated by using gamma-ray spectrometry. An extensive radioecological study was carried out between 2010 and 2013 in Mount IDA/Kazdagi, located in Edremit region in Turkey. A total of 341 soil samples were collected from the surface and organic horizons (OL, OF+OH, and A) in 118 soil profiles. The distributions of natural radioactivity levels in these horizons and corresponding absorbed dose rates from outdoors terrestrial gamma radiation throughout the region were mapped in detail. Mean (40)K activity values over the combined horizons varied between 43 and 1,008 Bq kg(-1); whereas, mean (226)Ra and (232)Th concentrations over the combined horizons ranged between 5-152 and 6-275 Bq kg(-1), respectively. Our data indicate that the radioactivity values of the study sites were within the universal normal range. The significant variation among the (232)Th, (226)Ra, and (40)K activities and gamma dose rate might be due to the geological variation in the study sites.

  16. Non-destructive Assay Measurements Using the RPI Lead Slowing Down Spectrometer

    SciTech Connect

    Becker, Bjorn; Weltz, Adam; Kulisek, Jonathan A.; Thompson, J. T.; Thompson, N.; Danon, Yaron

    2013-10-01

    The use of a Lead Slowing-Down Spectrometer (LSDS) is consid- ered as a possible option for non-destructive assay of fissile material of used nuclear fuel. The primary objective is to quantify the 239Pu and 235U fissile content via a direct measurement, distinguishing them through their characteristic fission spectra in the LSDS. In this pa- per, we present several assay measurements performed at the Rensse- laer Polytechnic Institute (RPI) to demonstrate the feasibility of such a method and to provide benchmark experiments for Monte Carlo cal- culations of the assay system. A fresh UOX fuel rod from the RPI Criticality Research Facility, a 239PuBe source and several highly en- riched 235U discs were assayed in the LSDS. The characteristic fission spectra were measured with 238U and 232Th threshold fission cham- bers, which are only sensitive to fission neutron with energy above the threshold. Despite the constant neutron and gamma background from the PuBe source and the intense interrogation neutron flux, the LSDS system was able to measure the characteristic 235U and 239Pu responses. All measurements were compared to Monte Carlo simula- tions. It was shown that the available simulation tools and models are well suited to simulate the assay, and that it is possible to calculate the absolute count rate in all investigated cases.

  17. Thorium determination in intercomparison samples and in some Romanian building materials by gamma ray spectrometry.

    PubMed

    Pantelica, A; Georgescu, I I; Murariu-Magureanu, M D; Margaritescu, I; Cincu, E

    2001-01-01

    Thorium content in zircon sand, thorium ore and a thorium liquid sample (EU Laboratories Network Intercomparison), as well as in some Romanian building materials: sand, wood, tufa, asbestos-cement. cement mill dust, coal fly ash, bricks, and tile (28 samples) was deterimined by gamma ray spectrometry. For the building materials, 226Ra, 40K and 137Cs specific activities were also measured. The results were compared with the Romanian legal norms concerning the highest admissible levels for 232Th, 226Ra. and 40K radioactivity. and to Th, U, and K concentration values previously determined in our laboratory on similar types of samples.

  18. The 55K protein on the 5' termini of adenovirus type 2 DNA is unrelated to virus-coded candidate transformation proteins (E1-53K, E1-40K-50K) and DNA-binding proteins (E2-42K/47K/73K).

    PubMed

    Green, M; Wold, W S; Brackmann, K H; Cartas, M A

    1979-09-01

    A polypeptide of 55,000 daltons (55K) is linked, probably covalently, to the K' termini of adenovirus type 2 DNA. The 55K polypeptide is synthesized during early stages of infection (T. Yamashita, M. Arens, and M. Green, J. Virol. 30: 497-507, 1979) and thus may function in viral DNA replication, gene regulation, or cell transformation. Several virus-coded early polypeptides have been identified that could correspond to the terminal 55K, including the E1-40K-50K and E1-53K candidate transformation polypeptides and the E2-42K/47K/73K single-stranded DNA-binding polypeptide. We show here that two-dimensional tryptic [35S]methionine-peptide maps of the terminal 55K differ completely from [35S]methionine-peptide maps of four related E1-40K-50K polypeptides, the E1-53K, and the related E2-42K, E2-47K, and E2-73K polypeptides. We conclude that the terminal 55K polypeptide does not correspond to any of the known virus-coded early polypeptides.

  19. Dynamic nuclear polarization at 40 kHz magic angle spinning† †Electronic supplementary information (ESI) available: Experimental details, with supplementary tables and figures. See DOI: 10.1039/c6cp00839a Click here for additional data file.

    PubMed Central

    Chaudhari, Sachin R.; Berruyer, Pierrick; Gajan, David; Reiter, Christian; Engelke, Frank; Silverio, Daniel L.; Copéret, Christophe; Lelli, Moreno

    2016-01-01

    DNP-enhanced solid-state NMR spectroscopy under magic angle spinning (MAS) is rapidly developing into a powerful analytical tool to investigate the structure of a wide range of solid materials, because it provides unsurpassed sensitivity gains. Most developments and applications of DNP MAS NMR were so far reported at moderate spinning frequencies (up to 14 kHz using 3.2 mm rotors). Here, using a 1.3 mm MAS DNP probe operating at 18.8 T and ∼100 K, we show that signal amplification factors can be increased by up to a factor two when using smaller volume rotors as compared to 3.2 mm rotors, and report enhancements of around 60 over a range of sample spinning rates from 10 to 40 kHz. Spinning at 40 kHz is also shown to increase 29Si coherence lifetimes by a factor three as compared to 10 kHz, substantially increasing sensitivity in CPMG type experiments. The contribution of quenching effects to the overall sensitivity gain at very fast MAS is evaluated, and applications are reported on a functionalised mesostructured organic–inorganic material. PMID:27035630

  20. Assessment of natural radioactivity levels in rocks and their relationships with the geological structure of Johor state, Malaysia.

    PubMed

    Alnour, I A; Wagiran, H; Ibrahim, N; Hamzah, S; Elias, M S; Laili, Z; Omar, M

    2014-01-01

    The distribution of natural radionuclides ((238)U, (232)Th and (40)K) and their radiological hazard effect in rocks collected from the state of Johor, Malaysia were determined by gamma spectroscopy using a high-purity germanium detector. The highest values of (238)U, (232)Th and (40)K activity concentrations (67±6, 85±7 and 722±18 Bg kg(-1), respectively) were observed in the granite rock. The lowest concentrations of (238)U and (232)Th (2±0.1 Bq kg(-1) for (238)U and 2±0.1 Bq kg(-1) for (232)Th) were observed in gabbro rock. The lowest concentration of (40)K (45±2 Bq kg(-1)) was detected in sandstone. The radium equivalent activity concentrations for all rock samples investigated were lower than the internationally accepted value of 370 Bq kg(-1). The highest value of radium equivalent in the present study (239±17 Bq kg(-1)) was recorded in the area of granite belonging to an acid intrusive rock geological structure. The absorbed dose rate was found to range from 4 to 112 nGy h(-1). The effective dose ranged from 5 to 138 μSv h(-1). The internal and external hazard index values were given in results lower than unity. The purpose of this study is to provide information related to radioactivity background levels and the effects of radiation on residents in the study area under investigation. Moreover, the relationships between the radioactivity levels in the rocks within the geological structure of the studied area are discussed. PMID:23965286

  1. Assessment of natural radioactivity levels in rocks and their relationships with the geological structure of Johor state, Malaysia.

    PubMed

    Alnour, I A; Wagiran, H; Ibrahim, N; Hamzah, S; Elias, M S; Laili, Z; Omar, M

    2014-01-01

    The distribution of natural radionuclides ((238)U, (232)Th and (40)K) and their radiological hazard effect in rocks collected from the state of Johor, Malaysia were determined by gamma spectroscopy using a high-purity germanium detector. The highest values of (238)U, (232)Th and (40)K activity concentrations (67±6, 85±7 and 722±18 Bg kg(-1), respectively) were observed in the granite rock. The lowest concentrations of (238)U and (232)Th (2±0.1 Bq kg(-1) for (238)U and 2±0.1 Bq kg(-1) for (232)Th) were observed in gabbro rock. The lowest concentration of (40)K (45±2 Bq kg(-1)) was detected in sandstone. The radium equivalent activity concentrations for all rock samples investigated were lower than the internationally accepted value of 370 Bq kg(-1). The highest value of radium equivalent in the present study (239±17 Bq kg(-1)) was recorded in the area of granite belonging to an acid intrusive rock geological structure. The absorbed dose rate was found to range from 4 to 112 nGy h(-1). The effective dose ranged from 5 to 138 μSv h(-1). The internal and external hazard index values were given in results lower than unity. The purpose of this study is to provide information related to radioactivity background levels and the effects of radiation on residents in the study area under investigation. Moreover, the relationships between the radioactivity levels in the rocks within the geological structure of the studied area are discussed.

  2. Frequency-dependent impedance spectroscopy on the 0.925(Bi0.5Na0.40K0.10)TiO3-0.075(Ba0.70Sr0.30)TiO3 ceramic

    NASA Astrophysics Data System (ADS)

    Ullah, Amir; Rahman, Muneeb-ur; Iqbal, Muhammad Javid; Ahn, Chang Won; Kim, Ill Won; Ullah, Aman

    2016-06-01

    The electrical properties of the 0.925(Bi0.5(Na0.40K0.10)TiO3-0.075(Ba0.70Sr0.30)TiO3 (0.925BNKT-0.075BST) ceramic were investigated by using AC impedance spectroscopy over a wide range of frequencies (10 -2 ~ 105 Hz). The X-ray diffraction patterns confirmed the formation of a single-phase compound. A single semicircular arc in the impedance spectrum indicates that the main contribution of the bulk resistance ( R b ) were due to grain effects, with Rb decreasing with increasing temperature. The conductivity of the ceramics increased with increasing temperature, and the activation energy resulting from the DC conductivity was 0.86 eV. The ceramic displayed a typical negative temperature coefficient of resistance (NTCR) behavior, like that of a semiconductor.

  3. Radioactivity of sand, groundwater and wild plants in northeast Sinai, Egypt.

    PubMed

    Ramadan, Khaled A; Seddeek, Mostafa K; Nijim, Abdelkareem; Sharshar, Taher; Badran, Hussein M

    2011-12-01

    The radioactivity levels are poorly studied in non-coastal arid regions. For this reason, 38 locations covering an area of about 350 km(2) in northeast Sinai, Egypt, were investigated by γ-ray spectroscopy. Moderately significant correlations among (238)U, (234)Th, and (226)Ra isotopes and low significant correlations between the concentrations of (238)U-series and (232)Th in sand were obtained. No evidence of correlation was found between the concentrations of radioisotopes and pH, grain size, total organic matter content, bicarbonate or calcium carbonate concentrations of the sand samples. The mean values of soil-to-plant transfer factor were 0.15, 0.18, 1.52 and 0.74 for (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. The range of concentrations of (226)Ra,( 232)Th, and (40)K in water samples collected from five wells were<0.4-0.16,<0.4-0.13, and<0.15-1.62 Bq l(-1), respectively. The mean absorbed dose rate in outdoor air at a height of 1 m above the ground surface for the sand samples was 19.4 nGy h(-1). The Ra(eq) activities of the sands are lower than the recommended maximum value of 370 Bq kg(-1) criterion limit for building materials.

  4. Evaluation of natural radioactivity and its associated health hazard indices of a South Indian river.

    PubMed

    Krishnamoorthy, N; Mullainathan, S; Mehra, R; Chaparro, Marcos A E; Chaparro, Mauro A E

    2014-12-01

    The activity concentration of the natural radionuclides (226)Ra, (232)Th and (40)K was measured for sediment samples collected from thirty-three different locations along the Bharathapuzha river basin by using high-resolution gamma-ray spectrometry. The concentrations of the natural radionuclides were found to vary from location to location, and their mean values are 19.6, 82.87 and 19.44% higher than the worldwide mean values of (226)Ra, (232)Th and (40)K, respectively. The value of (232)Th was found to be higher than that of (226)Ra in 82% of the samples collected for this study. The calculated values of indoor gamma dose rate (DIN) ranged between 89.55 and 194.24 nGy h(-1), and the overall mean value is 63.2% higher than the recommended safe and criterion limit by UNSCEAR. The internal and external hazard indices (H(in) and H(ex)), the representative gamma index and alpha index (I(gamma) and I(alpha)), the annual gonad dose equivalent (AGDE) and the excess lifetime cancer risk (ELCR) were also calculated and compared with the international recommended values. Multivariate statistical analyses were also carried out to determine the relation between the natural radionuclides and various radiological parameters.

  5. Distribution of low-level natural radioactivity in a populated marine region of the Eastern Mediterranean Sea.

    PubMed

    Evangeliou, Nikolaos; Florou, Heleny; Kritidis, Panayotis

    2012-12-01

    The levels of natural radioactivity have been evaluated in the water column of an eastern Mediterranean region (Saronikos Gulf), with respect to the relevant environmental parameters. A novel methodology was used for the determination of natural radionuclides, which substitutes the time-consuming radiochemical analysis, based on an in situ sample preconcentration using ion-selective manganese fibres placed on pumping systems. With regard to the results obtained, (238)U-series radionuclides were found at the same level or lower than those observed previously in Mediterranean regions indicating the absence of technologically enhanced naturally occurring radioactive material (TENORM) activities in the area. Similar results were observed for the (232)Th-series radionuclides and (40)K in the water column in comparison with the relevant literature on the Mediterranean Sea. The calculated ratios of (238)U-(232)Th and (40)K-(232)Th verified the lack of TENORM contribution in the Saronikos Gulf. Finally, a rough estimation was attempted concerning the residence times of fresh water inputs from a treatment plant of domestic wastes (Waste Water Treatment Plant of Psitalia) showing that fresh waters need a maximum of 15.7±7.6 d to be mixed with the open sea water.

  6. Natural Radioactivity in Soil and Water from Likuyu Village in the Neighborhood of Mkuju Uranium Deposit

    PubMed Central

    Mohammed, Najat K.; Mazunga, Mohamed S.

    2013-01-01

    The discovery of high concentration uranium deposit at Mkuju, southern part of Tanzania, has brought concern about the levels of natural radioactivity at villages in the neighborhood of the deposit. This study determined the radioactivity levels of 30 soil samples and 20 water samples from Likuyu village which is 54 km east of the uranium deposit. The concentrations of the natural radionuclides 238U, 232Th, and 40K were determined using low level gamma spectrometry of the Tanzania Atomic Energy Commission (TAEC) Laboratory in Arusha. The average radioactivity concentrations obtained in soil samples for 238U (51.7 Bq/kg), 232Th (36.4 Bq/kg), and 40K (564.3 Bq/kg) were higher than the worldwide average concentrations value of these radionuclides reported by UNSCEAR, 2000. The average activity concentration value of 238U (2.35 Bq/L) and 232Th (1.85 Bq/L) in water samples was similar and comparable to their mean concentrations in the control sample collected from Nduluma River in Arusha. PMID:23781247

  7. Elemental bio-imaging of thorium, uranium, and plutonium in tissues from occupationally exposed former nuclear workers.

    PubMed

    Hare, Dominic; Tolmachev, Sergei; James, Anthony; Bishop, David; Austin, Christine; Fryer, Fred; Doble, Philip

    2010-04-15

    Internal exposure from naturally occurring radionuclides (including the inhaled long-lived actinides (232)Th and (238)U) is a component of the ubiquitous background radiation dose (National Council on Radiation Protection and Measurements. Ionizing radiation exposure of the population of the United States; NCRP Report No. 160; NCRP: Bethesda, MD, 2009). It is of interest to compare the concentration distribution of these natural alpha-emitters in the lungs and respiratory lymph nodes with those resulting from occupational exposure, including exposure to anthropogenic plutonium and depleted and enriched uranium. This study examines the application of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS) to quantifying and visualizing the mass distribution of uranium and thorium isotopes from both occupational and natural background exposure in human respiratory tissues and, for the first time, extends this application to the direct imaging of plutonium isotopes. Sections of lymphatic and lung tissues taken from deceased former nuclear workers with a known history of occupational exposure to specific actinide elements (uranium, plutonium, or americium) were analyzed by LA-ICPMS. Using a previously developed LA-ICPMS protocol for elemental bio-imaging of trace elements in human tissue and a new software tool, we generated images of thorium ((232)Th), uranium ((235)U and (238)U), and plutonium ((239)Pu and (240)Pu) mass distributions in sections of tissue. We used a laboratory-produced matrix-matched standard to quantify the (232)Th, (235)U, and (238)U concentrations. The plutonium isotopes (239)Pu and (240)Pu were detected by LA-ICPMS in 65 mum diameter localized regions of both a paratracheal lymph node and a sample of lung tissue from a person who was occupationally exposed to refractory plutonium (plutonium dioxide). The average (overall) (239)Pu concentration in the lymph node was 39.2 ng/g, measured by high purity germanium (HPGe) gamma

  8. General constraints on the age and chemical evolution of the Galaxy

    SciTech Connect

    Meyer, B.S.; Schramm, D.N.

    1986-05-01

    The formalism of Schramm and Wasserburg (1970) for determining the mean age of the elements is extended. Model-independent constraints (constraints that are independent of a specific form for the effective nucleosynthesis rate and Galactic chemical evolution over time) are derived on the first four terms in the expansion giving the mean age of the elements, and from these constraints limits are derived on the total duration of nucleosynthesis. These limits require only input of the Schramm-Wasserburg parameter ..delta../sup max/ and of the ratio of the mean time for formation of the elements to the total duration of nucleosynthesis, t/sub nu//T. The former quantity is a function of nuclear input parameters. Limits on the latter are obtained from constraints on the relative rate of nucleosynthesis derived from the /sup 232/Th//sup 238/U, /sup 235/U//sup 238/U, and shorter-lived chronometric pairs. 65 refs.

  9. Indirect Determination of the 230Th(n,f) and 231Th(n,f) Cross Sections for Thorium-Based Nuclear Energy Systems

    SciTech Connect

    Stroberg, S.R.; Allmond, J.M.; Angell, C.; Bernstein, L.A.; Bleuel, D.L.; Burke, J.T.; Gibelin, J.; Phair, L.; Scielzo, N.D.; Swanberg, E.; Wiedeking, M.; Norman, E.B.; Goldblum, Bethany

    2009-09-11

    The Surrogate Ratio Method (SRM) was employed in the first experimental determination of the 231Th(n,f) cross section, relative to the 235U(n,f) cross section, over an equivalent neutron energy range of 360 keV to 10 MeV. The 230Th(n,f) cross section was also deduced using the SRM, relative to the 234U(n,f) cross section, over an equivalent neutron energy range of 220 keV to 25 MeV. The desired compound nuclei were populated using (3He,3He) and (3He) reactions on targets of 232Th and 236U and relative fission decay probabilities were measured. The surrogate 230,231Th(n,f) cross sections were compared to cross section evaluations and directly-measured experimental data, where available.

  10. [Cytogenetic effects in Allium schoenoprasum growing on the anthropogenically contaminated soil].

    PubMed

    Belykh, E S; Maystrenko, T A

    2015-01-01

    Cytogenetic effects in Allium schoenoprasum meristematic root tip cells grown for a year on the territory contaminated with 235U, 238U and 232Th decay series radionuclides, heavy metals and As were studied. The area is characterized with different concentrations of chemical compounds in soil affecting a toxic element migration in biocoenosis. Analysis of the chromosome aberration spectrum showed an ambiguous cell response to soil contamination. Within the weighted absorbed dose range up to 1.2 Gy the higher the dose the aberrant cell frequency increase was shown. But further increase in the dose resulted in a genotoxic effect decrease due to high toxic effects of heavy metals and radionuclides in soil. This was registered as a mitotic index decrease that can provoke a chromosome aberration frequency underestimation and result in erroneous conclusions about genotoxic effects in A. schoenoprasum used as a bioindicator. PMID:25962271

  11. MANTRA: An Integral Reactor Physics Experiment to Infer Actinide Capture Cross-sections from Thorium to Californium with Accelerator Mass Spectrometry

    SciTech Connect

    G. Youinou; C. McGrath; G. Imel; M. Paul; R. Pardo; F. Kondev; M. Salvatores; G. Palmiotti

    2011-08-01

    The principle of the proposed experiment is to irradiate very pure actinide samples in the Advanced Test Reactor at INL and, after a given time, determine the amount of the different transmutation products. The determination of the nuclide densities before and after neutron irradiation will allow inference of effective neutron capture cross-sections. This approach has been used in the past and the novelty of this experiment is that the atom densities of the different transmutation products will be determined using the Accelerator Mass Spectrometry technique at the ATLAS facility located at ANL. It is currently planned to irradiate the following isotopes: 232Th, 235U, 236U, 238U, 237Np, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, 241Am, 243Am, 244Cm and 248Cm.

  12. AN INTEGRAL REACTOR PHYSICS EXPERIMENT TO INFER ACTINIDE CAPTURE CROSS-SECTIONS FROM THORIUM TO CALIFORNIUM WITH ACCELERATOR MASS SPECTROMETRY

    SciTech Connect

    G. Youinou; M. Salvatores; M. Paul; R. Pardo; G. Palmiotti; F. Kondev; G. Imel

    2010-04-01

    The principle of the proposed experiment is to irradiate very pure actinide samples in the Advanced Test Reactor (ATR) at INL and, after a given time, determine the amount of the different transmutation products. The determination of the nuclide densities before and after neutron irradiation will allow inference of effective neutron capture cross-sections. This approach has been used in the past and the novelty of this experiment is that the atom densities of the different transmutation products will be determined using the Accelerator Mass Spectroscopy (AMS) technique at the ATLAS facility located at ANL. It is currently planned to irradiate the following isotopes: 232Th, 235U, 236U, 238U, 237Np, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, 241Am, 243Am and 248Cm.

  13. Enrichment and particle size dependence of polonium and other naturally occurring radionuclides in coal ash.

    PubMed

    Sahu, S K; Tiwari, M; Bhangare, R C; Pandit, G G

    2014-12-01

    Coal fired thermal power contributes 70% of power in India. Coal fired power generation results in huge amounts of fly ash and bottom ash of varying properties. Coal, which contains the naturally occurring radionuclides, on burning results in enrichment of these radionuclides in the ashes. In the present study, coal, bottom ash and fly ash samples collected from six coal-fired power plants in India were measured for (210)Po using alpha spectrometry and for natural U, (226)Ra, (232)Th and (40)K by an HPGe γ-ray spectrometer. (210)Po in fly ash ranged from 25.7 to 70 Bq/kg with a mean value of 40.5 Bq/kg. The range and mean activities of (238)U, (226)Ra, (232)Th, (40)K in fly ash were 38.5-101 (78.1), 60-105.7 (79), 20-125 (61.7) and 43.6-200 (100) Bq/kg respectively. Fly ash and bottom ash contains two to five times more natural radionuclides than feed coal. The results were compared with the available data from earlier studies in other countries. The effect of particle size on enrichment factor of the nuclides in fly ash was studied. (210)Po showed the largest size dependence with its concentration favoring the smaller particle size while (232)Th showed least size dependence. (238)U and (226)Ra showed behavior intermediate to that of (210)Po and (232)Th. Also the correlation between sulfur content of the feed coal and activity of (210)Po was investigated. Increased sulfur content in feed coal enhanced enrichment of (210)Po in ash.

  14. Enrichment and particle size dependence of polonium and other naturally occurring radionuclides in coal ash.

    PubMed

    Sahu, S K; Tiwari, M; Bhangare, R C; Pandit, G G

    2014-12-01

    Coal fired thermal power contributes 70% of power in India. Coal fired power generation results in huge amounts of fly ash and bottom ash of varying properties. Coal, which contains the naturally occurring radionuclides, on burning results in enrichment of these radionuclides in the ashes. In the present study, coal, bottom ash and fly ash samples collected from six coal-fired power plants in India were measured for (210)Po using alpha spectrometry and for natural U, (226)Ra, (232)Th and (40)K by an HPGe γ-ray spectrometer. (210)Po in fly ash ranged from 25.7 to 70 Bq/kg with a mean value of 40.5 Bq/kg. The range and mean activities of (238)U, (226)Ra, (232)Th, (40)K in fly ash were 38.5-101 (78.1), 60-105.7 (79), 20-125 (61.7) and 43.6-200 (100) Bq/kg respectively. Fly ash and bottom ash contains two to five times more natural radionuclides than feed coal. The results were compared with the available data from earlier studies in other countries. The effect of particle size on enrichment factor of the nuclides in fly ash was studied. (210)Po showed the largest size dependence with its concentration favoring the smaller particle size while (232)Th showed least size dependence. (238)U and (226)Ra showed behavior intermediate to that of (210)Po and (232)Th. Also the correlation between sulfur content of the feed coal and activity of (210)Po was investigated. Increased sulfur content in feed coal enhanced enrichment of (210)Po in ash. PMID:24813148

  15. Gamma-spectrometric measurement of radioactivity in agricultural soils of the Lombardia region, northern Italy.

    PubMed

    Guidotti, Laura; Carini, Franca; Rossi, Riccardo; Gatti, Marina; Cenci, Roberto M; Beone, Gian Maria

    2015-04-01

    This work is part of a wider monitoring project of the agricultural soils in Lombardia, which aims to build a database of topsoil properties and the potentially toxic elements, organic pollutants and gamma emitting radionuclides that the topsoils contain. A total of 156 agricultural soils were sampled according to the LUCAS (Land Use/Cover Area frame statistical Survey) standard procedure. The aim was to provide a baseline to document the conditions present at the time of sampling. The results of the project concerning soil radioactivity are presented here. The aim was to assess the content of (238)U, (232)Th, (137)Cs and (40)K by measuring soil samples by gamma spectrometry. (238)U, (232)Th and (40)K activities range 24-231, 20-70, and 242-1434 Bq kg(-1) respectively. The geographic distribution of (238)U reflects the geophysical framework of the Lombardia region: the soils with high content of uranium are distributed for the most part in the South Alpine belt, where the presence of magmatic rocks is widespread. These soils show an higher activity of (238)U than of (232)Th. The (238)U activities become lower than (232)Th when soils are located in the plain, originating from basic sedimentary rocks. (137)Cs activity ranges 0.4-86.8 kBq m(-2). The lowest activity of (137)Cs is in the plain, whereas the highest is in the North on soils kept as lawn or pasture. The (137)Cs activity of some samples suggests the presence of accumulation processes that lead to (137)Cs enriched soils. This is the first survey of gamma emitting radionuclides in Lombardia that is based on the LUCAS standard sampling. The results from this monitoring campaign are important for the human radiation exposure and provide the zero point, which will be useful for assessing future effects due to external factors such as human activities. PMID:25636137

  16. Gamma-spectrometric measurement of radioactivity in agricultural soils of the Lombardia region, northern Italy.

    PubMed

    Guidotti, Laura; Carini, Franca; Rossi, Riccardo; Gatti, Marina; Cenci, Roberto M; Beone, Gian Maria

    2015-04-01

    This work is part of a wider monitoring project of the agricultural soils in Lombardia, which aims to build a database of topsoil properties and the potentially toxic elements, organic pollutants and gamma emitting radionuclides that the topsoils contain. A total of 156 agricultural soils were sampled according to the LUCAS (Land Use/Cover Area frame statistical Survey) standard procedure. The aim was to provide a baseline to document the conditions present at the time of sampling. The results of the project concerning soil radioactivity are presented here. The aim was to assess the content of (238)U, (232)Th, (137)Cs and (40)K by measuring soil samples by gamma spectrometry. (238)U, (232)Th and (40)K activities range 24-231, 20-70, and 242-1434 Bq kg(-1) respectively. The geographic distribution of (238)U reflects the geophysical framework of the Lombardia region: the soils with high content of uranium are distributed for the most part in the South Alpine belt, where the presence of magmatic rocks is widespread. These soils show an higher activity of (238)U than of (232)Th. The (238)U activities become lower than (232)Th when soils are located in the plain, originating from basic sedimentary rocks. (137)Cs activity ranges 0.4-86.8 kBq m(-2). The lowest activity of (137)Cs is in the plain, whereas the highest is in the North on soils kept as lawn or pasture. The (137)Cs activity of some samples suggests the presence of accumulation processes that lead to (137)Cs enriched soils. This is the first survey of gamma emitting radionuclides in Lombardia that is based on the LUCAS standard sampling. The results from this monitoring campaign are important for the human radiation exposure and provide the zero point, which will be useful for assessing future effects due to external factors such as human activities.

  17. Clay Mineral: Radiological Characterization

    SciTech Connect

    Cotomacio, J. G.; Silva, P. S. C.; Mazzilli, B. P

    2008-08-07

    Since the early days, clays have been used for therapeutic purposes. Nowadays, most minerals applied as anti-inflammatory, pharmaceutics and cosmetic are the clay minerals that are used as the active ingredient or, as the excipient, in formulations. Although their large use, few information is available in literature on the content of the radionuclide concentrations of uranium and thorium natural series and {sup 40}K in these clay minerals.The objective of this work is to determine the concentrations of {sup 238}U, {sup 232}Th, {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 40}K in commercial samples of clay minerals used for pharmaceutical or cosmetic purposes. Two kinds of clays samples were obtained in pharmacies, named green clay and white clay.Measurement for the determination of {sup 238}U and {sup 232}Th activity concentration was made by alpha spectrometry and gamma spectrometry was used for {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 40}K determination. Some physical-chemical parameters were also determined as organic carbon and pH. The average activity concentration obtained was 906{+-}340 Bq kg{sup -1} for {sup 40}K, 40{+-}9 Bq kg{sup -1} for {sup 226}Ra, 75{+-}9 Bq kg{sup -1} for {sup 228}Ra, 197{+-}38 Bq kg{sup -1} for {sup 210}Pb, 51{+-}26 Bq kg{sup -1} for {sup 238}U and 55{+-}24 Bq kg{sup -1} for {sup 232}Th, considering both kinds of clay.

  18. Cleanup levels for Am-241, Pu-239, U-234, U-235 & U-238 in soils at the Rocky Flats Environmental Technology Site

    SciTech Connect

    Roberts, R.; Colby, B.; Brooks, L.; Slaten, S.

    1997-07-03

    This presentation briefly outlines a cleanup program at a Rocky Flats site through viewgraphs and an executive summary. Exposure pathway analyses to be performed are identified, and decontamination levels are listed for open space and office worker exposure areas. The executive summary very briefly describes the technical approach, RESRAD computer code to be used for analyses, recommendations for exposure levels, and application of action levels to multiple radionuclide contamination. Determination of action levels for surface and subsurface soils, based on radiation doses, is discussed. 1 tab.

  19. Calculation of K{sub {infinity}} for homogeneous {sup 235}U metal mixtures: Will the real K{sub {infinity}} please stand up?

    SciTech Connect

    Jordan, W.C.; Petrie, L.M.; Wright, R.Q.; Parks, C.V.

    1997-06-01

    This paper very briefly analyzes a journal article about calculating k{sub {infinity}} for metals mixed with uranium 235, and compares the article results with other calculation methods. The article suggested that continuous energy cross sections gave more accurate results than groupwise cross sections. The mixtures described in the article were dry, fast systems with several unusual characteristics; however, the majority of multigroup libraries used for analysis were developed for well moderated thermal systems. The results of calculations performed using several different codes and cross sections for three uranium/metal mixtures are presented in this paper. 1 tab.

  20. Accurate fast method with high chemical yield for determination of uranium isotopes (234U, 235U, 238U) in granitic samples using alpha spectroscopy

    NASA Astrophysics Data System (ADS)

    Guirguis, Laila A.; Farag, Nagdy M.; Salim, Adham K.

    2015-03-01

    The present study aims to use the α-spectroscopy at Nuclear Materials Authority (NMA) of Egypt. A radiochemical technique for analysis uranium isotopes was carried out for ten mineralized granitic samples together with the International standards RGU-1 (IAEA) and St4 (NMA). Several steps of sample preparation, radiochemical separation and source preparation were performed before analysis. Uranium was separated from sample matrix with 0.2 M TOPO in cyclohexane as an extracting agent with a chemical yield 98.95% then uranium was purified from lanthanides and actinides present with 0.2 M TOA in xylene as an extracting agent. The pure fraction was electrodeposited on a mirror-polished copper disc from buffer solution (NaHSO4+H2SO4+NH4OH). Rectangle pt-electrode with an anode-cathode distance of 2 cm was used. Current was 900 mA and the electrodeposition time reach up to 120 min. The achieved results show that the chemical yield ranged between 87.9±6.8 and 98±8.6.

  1. Determination of (235)U, (239)Pu, (240)Pu, and (241)Am in a nuclear bomb particle using a position-sensitive α-γ coincidence technique.

    PubMed

    Peräjärvi, Kari A; Ihantola, Sakari; Pöllänen, Roy C; Toivonen, Harri I; Turunen, Jani A

    2011-02-15

    A nuclear bomb particle containing 1.6 ng of Pu was investigated nondestructively with a position-sensitive α detector and a broad-energy HPGe γ-ray detector. An event-mode data acquisition system was used to record the data. α-γ coincidence counting was shown to be well suited to nondestructive isotope ratio determination. Because of the very small background, the 51.6 keV γ rays of (239)Pu and the 45.2 keV γ rays of (240)Pu were identified, which enabled isotopic ratio calculations. In the present work, the (239)Pu/((239)Pu+(240)Pu) atom ratio was determined to be 0.950 ± 0.010. The uncertainties were much smaller than in the previous more conventional nondestructive studies on this particle. Obtained results are also in good agreement with the data from the destructive mass spectrometric studies obtained previously by other investigators.

  2. A refined model for 235U( n,f) prompt fission neutron multiplicity and spectrum calculation with validation in integral benchmarks

    NASA Astrophysics Data System (ADS)

    Tudora, Anabella; Morillon, B.; Hambsch, F.-J.; Vladuca, G.; Oberstedt, S.

    2005-06-01

    The prompt fission neutron multiplicity and spectra of the n+U235 reaction are calculated for the first time with a refined model that takes into account the entire fission fragment range with a point-by-point treatment. At higher incident neutron energies, the treatment of neutrons evaporated prior to scission is improved by the use of the ( n,xn) spectra obtained in the frame of the cross-section calculation (compound nucleus and pre-equilibrium mechanisms). The new prompt fission neutron multiplicity and spectra up to 30 MeV incident neutron energy, included in the U-235 BRC/JEFF3.1t evaluation, lead to very good K results with the fast and thermal integral benchmarks.

  3. Porous flow model for steady state transport of radium in groundwater

    SciTech Connect

    Davidson, M.R.; Dickson, B.L.

    1986-01-01

    The quasi-steady variation of uranium and radium isotopes from the decay of /sup 238/U, /sup 235/U, and /sup 232/Th has been determined along an idealized, one-dimensional aquifer which is a distributed source of activity and from which the transfer of radionuclides to solution occurs by alpha recoil and chemical exchange. The model includes the effects of dispersive flow and retardation by adsorption. The importance of these effects on the variation of U and Ra activity ratios along the model aquifer is shown. Predicted limiting activity ratios (for large flow times) of /sup 226/Ra//sup 223/Ra, /sup 224/Ra//sup 228/Ra, and /sup 226/Ra//sup 228/ are 21.4, 1.5, and (approx. 1.7 - 2.0) (U/Th)/sub s/, respectively (where (U/Th)/sub s/ is the activity ratio /sup 238/U//sup 232/Th in the aquifer rocks), although in many cases, an aquifer may not be long enough for the ratios involving /sup 226/Ra to achieve their limiting values.

  4. Development of the NIST bone ash standard reference material for environmental radioactivity measurement.

    PubMed

    Lin, Z; Inn, K G; Altzitzoglou, T; Arnold, D; Cavadore, D; Ham, G J; Korun, M; Wershofen, H; Takata, Y; Young, A

    1998-01-01

    The bone ash standard reference material (SRM), a blend of 4% contaminated human bone and 96% diluent bovine bone, has been developed for radiochemical method validation and quality control for radio-bone analysis. The massic activities of 90Sr, 226Ra, 230Th, 232Th, 234U, 235U, 238U, 238Pu, (239 + 240)Pu and (243 + 244)Cm were certified using a variety of radiochemical procedures and detection methods. Measurements confirmed undetectable radionuclide heterogeneity down to a sample size of 5 g. thereby implying adequate blending of particulate materials with dilution factors of up to 17,900. The results among most of the intercomparison laboratories and their methods were consistent. Disequilibrium was observed for decay chains: 234U(0.67 mBq/g)-230Th(0.47 mBq/g)-226Ra(15.1 mBq/g)-210Pb(23 mBq/g)-210Po(13 mBq/g) and 232Th(0.99 mBq/g)-228 Ra(6.1 mBq/g)-228Th(7.1 mBq/g). The disequilibria were the results of mixing occupationally contaminated human bone with natural bovine bone and the fractionation during internal biological processes. The massic activity of 210Pb, 228Th and 241Am were not certified because of insufficient 228Ra and 241Pu data and lack of knowledge in how 222Rn and its daughters will be fractionated in the SRM bottle over time.

  5. Shape of spectra and mean energies of prompt fission neutrons from {sup 237}Np fission induced by primary neutrons of energy in the range E{sub n} < 20 MeV

    SciTech Connect

    Svirin, M. I.

    2008-10-15

    An analysis of the spectrum of prompt neutrons originating from {sup 237}Np fission induced by primary neutrons of energy E{sub n} = 14.7 MeV confirms the results obtained previously for {sup 232}Th (E{sub n} = 14.7, 17.7 MeV), {sup 235}U (14.7 MeV), and {sup 238}U (13.2, 14.7, 16, and 17.7 MeV) nuclei. In the experimental spectrum measured in the emissive fission of {sup 237}Np, there is also an excess of soft neutrons in the energy range E < 2 MeV in relation to what follows from a traditional theoretical description that considers two sources of prompt fission neutrons: fully accelerated fission fragments and excited nuclei prior to their separation. In just the same way as in the cases of {sup 232}Th and {sup 235,238}U, the shape of the prompt-fission-neutron spectrum for {sup 237}Np is reproduced theoretically over the entire measured range of secondary-neutron energies upon including nonaccelerated fragments as a third source of neutrons in the computational scheme. A description of the spectra and mean energies of prompt fission neutrons versus the bombarding-neutron energy is obtained on the basis of experimental data and their analysis. The results on mean energies are compared with data on the proton-induced fission of {sup 236,238}U nuclei.

  6. U, Np, Pu and Am Prompt Fission Neutron Spectra

    SciTech Connect

    Maslov, Vladimir M.

    2008-05-12

    Prompt fission neutron spectra (PFNS) components due to soft and hard pre-fission neutrons are revealed in PFNS data of {sup 232}Th(n,F), {sup 238}U(n,F), {sup 235}U(n,F) and {sup 239}Pu(n,F) reactions for E{sub n}{<=}20 MeV. Average energies of these PFNS are systematically shifted to higher values, so that Th fission fragments look least heated, while those of Pu--most heated. The average energy is correlated with the emissive fission chances contributions to the observed fission cross sections. The predicted contribution of (n,xnf) neutrons is most pronounced in case of {sup 232}Th(n,F) reaction. The approach, based on the consistent description of {sup 237}Np(n,F), {sup 237}Np(n,2n){sup 236s}Np and {sup 241}Am(n,F), {sup 241}Am(n,2n) is used to predict the PFNS of the {sup 237}Np(n,F) and {sup 241}Am(n,F) reactions.

  7. Impact of fertilizers on background radioactivity level in two newly developed desert areas

    NASA Astrophysics Data System (ADS)

    Ahmad, Fawzia

    A survey of soils and plants was carried out to determine the environmental gamma background radiation levels in two newly developed desert areas. The materials and the standards were analyzed by gamma spectroscopy; a shielded high purity germanium detector was used to measure the natural concentration of 238U, 232Th and 40K activities in the samples. The radionuclide content in some commercial fertilizers was determined. The results of the analysis of specific activities in the fertilizers under study were 1.27-950.09 Bq/kg for 238U, 0.73-162.16 Bq/kg for 232Th and 10.22-23845.24 Bq/kg for 40K. All natural soil samples showed low-activity concen-trations. The concentrations of 238U (6.13-38.84 Bq/kg) and 232Th (2.58-25.69 Bq/kg) are quite similar, whereas that of 40K (113.91-9314.11 Bq/kg) are much higher for plant samples. Some of the results obtained are larger than the permissible international radioactivity levels. It is suitable in this regard to compare the activity values of the imported fertilizers and that fabricated in Egypt. The absorbed dose rate was found to be 1.91-1027 nGy/h and the radium equivalent activity concentration was 4.02-1840.98 Bq/kg for fertilizer samples. Soil and plant sample results were 11.86-415E29 nGy/h and 24.20-750.52 Bq/kg for the absorbed dose rate and the radium equivalent activity concentration, respectively. Banana plant contains the largest values. This article presents actual data from investigations of the soil-plant transfer of the primordial radionuclides for some fruits growing on these soils. The transfer factors of 0.35-1.821 for 238U, 0.227-0.480 for 232Th and 1.95-31.85 for 40K were obtained. The increase of the transfer of 40K reflects its great uptake to the fruits. Observed soil-plant factors vary widely, mainly as a result of different soil, vegetation types and environmental conditions. Taking into account the transfer factors of 137Cs to plants, the measured activity concentrations of this isotope should not

  8. Factors affecting the distribution of natural and anthropogenic radionuclides in the coastal Burullus Lake.

    PubMed

    El-Reefy, H I; Badran, H M; Sharshar, T; Hilal, M A; Elnimr, T

    2014-08-01

    In the present study, measurements of naturally occurring radioactive materials and (137)Cs activity in sediment were conducted for locations covering the entire Burullus Lake in order to gather information about radionuclides mobility and distribution. Low-background γ-spectrometry was employed to determine the activity concentrations of water and sediment samples. The activity concentrations of (226)Ra and (232)Th are close to uniform distribution in the lake environment. Among the different physical and chemical characteristics measured for water and sediment, only salinity and total organic matter content have the potential to affect the mobility of (137)Cs and (40)K. The results suggest that these two radionuclides are attached to different mobile particulates. Increasing salinity tends to strengthen the adsorption of (137)Cs and solubilization of (40)K in sediment. On the other hand, sediment with high organic matter content traps (137)Cs and (40)K associated particulates to bottom sediment.

  9. Factors affecting the distribution of natural and anthropogenic radionuclides in the coastal Burullus Lake.

    PubMed

    El-Reefy, H I; Badran, H M; Sharshar, T; Hilal, M A; Elnimr, T

    2014-08-01

    In the present study, measurements of naturally occurring radioactive materials and (137)Cs activity in sediment were conducted for locations covering the entire Burullus Lake in order to gather information about radionuclides mobility and distribution. Low-background γ-spectrometry was employed to determine the activity concentrations of water and sediment samples. The activity concentrations of (226)Ra and (232)Th are close to uniform distribution in the lake environment. Among the different physical and chemical characteristics measured for water and sediment, only salinity and total organic matter content have the potential to affect the mobility of (137)Cs and (40)K. The results suggest that these two radionuclides are attached to different mobile particulates. Increasing salinity tends to strengthen the adsorption of (137)Cs and solubilization of (40)K in sediment. On the other hand, sediment with high organic matter content traps (137)Cs and (40)K associated particulates to bottom sediment. PMID:24657852

  10. Flow-injection technique for determination of uranium and thorium isotopes in urine by inductively coupled plasma mass spectrometry.

    PubMed

    Benkhedda, Karima; Epov, Vladimir N; Evans, R Douglas

    2005-04-01

    A sensitive and efficient flow-injection (FI) preconcentration and matrix-separation technique coupled to sector field ICP-mass spectrometry (SF-ICP-MS) has been developed and validated for simultaneous determination of ultra-low levels of uranium (U) and thorium (Th) in human urine. The method is based on selective retention of U and Th from a urine matrix, after microwave digestion, on an extraction chromatographic TRU resin, as an alternative to U/TEVA resin, and their subsequent elution with ammonium oxalate. Using a 10 mL sample, the limits of detection achieved for 238U and 232Th were 0.02 and 0.03 ng L(-1), respectively. The accuracy of the method was checked by spike-recovery measurements. Levels of U and Th in human urine were found to be in the ranges 1.86-5.50 and 0.176-2.35 ng L(-1), respectively, well in agreement with levels considered normal for non-occupationally exposed persons. The precision obtained for five replicate measurements of a urine sample was 2 and 3% for U and Th, respectively. The method also enables on-line measurements of the 235U/238U isotope ratios in urine. Precision of 0.82-1.04% (RSD) was obtained for 235U/238U at low ng L(-1) levels, using the FI transient signal approach.

  11. Measurement of gamma-ray intensities of 231Th using semiconductor detectors

    NASA Astrophysics Data System (ADS)

    Chatani, Hiroshi

    1999-04-01

    Nuclide 231Th was yielded by the 232Th(n, 2n) reaction with neutron irradiation in the Kyoto University Reactor (KUR). Moreover, the thorium was purified chemically. Gamma-ray spectra of thorium have been measured using low-energy photon spectrometers and a high-purity germanium detector. Relative γ-ray intensities ranging from 25 to 352 keV in the decay of 231Th have been determined with satisfactory accuracy. The results are in very good agreement with those of earlier studies. We observe two new γ-rays at 77.69 and 177.66 keV, whose intensities are found to be (0.063±0.010)% and (0.00095±0.00020)%, respectively, relative to that of 84.21 keV taken as 100%. Absolute intensity of 84.21 keV γ-ray which is the most prominent one from the decay of 231Th and that of 185.739 keV following the decay of 235U are also determined from the secular equilibrium for 235U- 231Th. The results obtained in two cases are (6.60±0.25)% and (58±2)%, respectively.

  12. Environmental-Impact Assessment of Natural Radioactivity Around a Traditional Mining Area in Al-Ibedia, Sudan.

    PubMed

    Idriss, Hajo; Salih, Isam; Alaamer, Abdulaziz S; Saleh, Almuaiz; Abdelgali, M Y

    2016-05-01

    Recently, in the Sudan, traditional gold mining has been growing rapidly and has become a very attractive and popular economic activity. Mining activity is recognized as one of the sources of radioactivity contamination. Hence, the radioactivity concentration and radiological hazard due to exposure of radionuclides (226)Ra, (232)Th, and (40)K were evaluated. The measurements were performed using gamma-ray spectrometry with an NaI (Tl) detector. The results show that (226)Ra, (232)Th, and (40)K activity concentration ranged from 2.66 to 18.47, 9.20 to 51.87, and 0.17 to 419.77 Bq/kg with average values of 7.54 ± 4.91, 20.74 ± 11.29, and 111.87 ± 136.84 Bq/kg, respectively. In contrast, (222)Rn in soil, (222)Rn in air, and (226)Ra in vegetables along with radiation dose were computed and compared with the international recommended levels. Potential radiological effects to miners and the public due to (226)Ra, (232)Th, (40)K, and (222)Rn are insignificant. (226)Ra transferred to vegetables appears to be negligible compared with the allowable limit 1.0 mSv/year set by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The average value of the annual gonadal dose equivalent (AGDE) is lower than the global average of 300 µSv/year (UNSCEAR 2000). However, some locations exhibit values >300 µSv/year. To the best of our knowledge, so far there seems to be no data regarding radioactivity monitoring in traditional mining areas in the Sudan. PMID:26979743

  13. Assessment of environmental radioactivity for Batman, Turkey.

    PubMed

    Damla, Nevzat; Cevik, Ugur; Kobya, Ali Ihsan; Ataksor, Berna; Isik, Umit

    2010-01-01

    The province of Batman, located in southern Anatolia, has a population of approximately 500,000. To our knowledge, there exists no information regarding the environmental radioactivity in this province. Therefore, gamma activity measurements in soil, building materials and water samples and an indoor radon survey have been carried out in the Batman province. The mean activity concentrations of the natural radionuclides (226Ra, 232Th and 40K) and a fission product (137Cs) were 35+/-8, 25+/-10, 274+/-167 and 12+/-7 Bq kg(-1), respectively, in the soil samples. The concentrations of 226Ra, 232Th and 40K in the selected building materials ranged from 18 to 48 Bq kg(-1), 8 to 49 Bq kg(-1) and 68 to 477 Bq kg(-1), respectively. All the calculated radium equivalent (Raeq) activity values of the building material samples are lower than the limit of 370 Bq kg(-1), equivalent to a gamma-dose of 1.5 mSv year(-1). The activity concentrations of 226Ra, 232Th and 40K in tap waters collected from the study area were determined with mean specific activity concentrations of 42+/-15, 35+/-9 and 524+/-190 mBq L(-1), respectively. Indoor radon measurements were made at 95 dwellings in Batman using a CR-39 detector. The radon concentration levels were found to vary from 23 to 145 Bq m(-3). The arithmetic mean of the measured radon concentration levels was found to be 84 Bq m(-3) with a standard deviation value of 23 Bq m(-3). The measurement results obtained in this study did not significantly differ from those taken in other parts of the country. The data generated in this study can be used to determine whether the Batman province is in a normal or high background radiation area and provides a valuable database for future estimations of the impact of radioactive pollution.

  14. Natural radioactivity in and radon exhalation from Finnish building materials.

    PubMed

    Mustonen, R

    1984-06-01

    A total of 369 samples of Finnish building materials were tested for their 226Ra, 232Th and 40K concentrations. The rate of radon exhalation was measured from 19 samples of material and 34 dwellings were tested for their room air ventilation rate and radon concentration. The mean values of 226Ra, 232Th and 40K concentrations in ballast materials for concrete production were 34.2 Bq X kg-1, 39.0 Bq X kg-1 and 964 Bq X kg-1, with standard deviations of 18.7 Bq X kg-1, 19.5 Bq X kg-1 and 265 Bq X kg-1, respectively. The activity concentrations were higher in clay bricks than in concrete, the mean values being 79.8 Bq X kg-1, 61.6 Bq X kg-1 and 986 Bq X kg-1 for 226Ra, 232Th and 40K, respectively. The normalized radon exhalation rates from 15-cm-thick concrete, slag-aggregate concrete and by-product gypsum were 0.38 (Bq X m-2 X h-1)/(Bq X kg-1), 0.15 (Bq X m-2 X h-1)/(Bq X kg-1), and 0.06 (Bq X m-2 X h-1)/(Bq X kg-1), respectively. The ventilation rates in dwellings varied between 0.27 and 1.99 air changes per h, the mean value being 0.60 h-1, and the corresponding steady state radon concentrations in room air varied from 17.0 to 149 Bq X m-3 in blocks of flats made of concrete and from 11.2 to 61.9 Bq X m-3 in blocks of flats made of brick.

  15. Measurement of gamma radiation levels in soil samples from Thanjavur using gamma-ray spectrometry and estimation of population exposure.

    PubMed

    Senthilkumar, B; Dhavamani, V; Ramkumar, S; Philominathan, P

    2010-01-01

    This study assesses the level of terrestrial gamma radiation and associated dose rates from the naturally occurring radionuclides (232)Th, (238)U and (40)K in 10 soil samples collected from Thanjavur (Tamil Nadu, India) using gamma-ray spectrometry. The activity profile of radionuclides has clearly showed the existence of low level activity in Thanjavur. The geometric mean activity concentrations of (232)Th, (238)U and (40)K is 42.9+/-9.4 Bq.kg(-1), 14.7+/-1.7 Bq.kg(-1) and 149.5+/-3.1 Bq.kg(-1) respectively are derived from all the soil samples studied. The activity concentration of (232)Th, (238)U and (40)K in soil is due to the presence of metamorphic rocks like shale, hornblende-biotite gneiss and quartzofeldspathic gneiss in these areas. Gamma absorbed dose rates in air outdoors were calculated to be in the range between 32 nGy.h(-1) and 59.1 nGy.h(-1) with an arithmetic mean of 43.3 +/-9 nGy.h(-1). This value is lesser than the population weighted world-averaged of 60 nGy.h(-1). Inhabitants of Thanjavur are subjected to external gamma radiation exposure (effective dose) ranging between 39.2 and 72.6 muSv.y(-1) with an arithmetic mean of 53.1+/-11 muSv.y(-1). The values of the external hazard index determined from the soil radioactivity of the study area are less than the recommended safe levels.

  16. Escaping radioactivity from coal-fired power plants (CPPs) due to coal burning and the associated hazards: a review.

    PubMed

    Papastefanou, Constantin

    2010-03-01

    Coal, like most materials found in nature, contains trace quantities of the naturally occurring primordial radionuclides, i.e. of (40)K and of (238)U, (232)Th and their decay products. Therefore, the combustion of coal results in the released into the environment of some natural radioactivity (1.48 TBq y(-1)), the major part of which (99%) escapes as very fine particles, while the rest in fly ash. The activity concentrations of natural radionuclides measured in coals originated from coal mines in Greece varied from 117 to 435 Bq kg(-1) for (238)U, from 44 to 255 Bq kg(-1) for (226)Ra, from 59 to 205 Bq kg(-1) for (210)Pb, from 9 to 41 Bq kg(-1) for (228)Ra ((232)Th) and from 59 to 227 Bq kg(-1) for (40)K. Fly ash escapes from the stacks of coal-fired power plants in a percentage of 3-1% of the total fly ash, in the better case. The natural radionuclide concentrations measured in fly ash produced and retained or escaped from coal-fired power plants in Greece varied from 263 to 950 Bq kg(-1) for (238)U, from 142 to 605 Bq kg(-1) for (226)Ra, from 133 to 428 Bq kg(-1) for (210)Pb, from 27 to 68 Bq kg(-1) for (228)Ra ((232)Th) and from 204 to 382 Bq kg(-1) for (40)K. About 5% of the total ash produced in the coal-fired power plants is used as substitute of cement in concrete for the construction of dwellings, and may affect indoor radiation doses from external irradiation and the inhalation of radon decay products (internal irradiation) is the most significant. The resulting normalized collective effective doses were 6 and 0.5man-Sv(GWa)(-1) for typical old and modern coal-fired power plants, respectively. PMID:20005612

  17. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico.

    PubMed

    Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

    2015-10-01

    Determining ionizing radiation in a geographic area serves to assess its effects on a population's health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h(-1). At the same sites, 48 soil samples were taken to obtain the activity concentrations of (226)Ra, (232)Th and (40)K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h(-1). Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg(-1), for (226)Ra, (232)Th and (40)K, respectively. From the analysis, the spatial distribution of (232)Th, (226)Ra and (40)K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize. PMID:26437425

  18. Assessment of Natural Radioactivity Levels of Cements and Cement Composites in the Slovak Republic

    PubMed Central

    Eštoková, Adriana; Palaščáková, Lenka

    2013-01-01

    The radionuclide activities of 226Ra, 232Th and 40K and radiological parameters (radium equivalent activity, gamma and alpha indices, the absorbed gamma dose rate and external and internal hazard indices) of cements and cement composites commonly used in the Slovak Republic have been studied in this paper. The cement samples of 8 types of cements from Slovak cement plants and five types of composites made from cement type CEM I were analyzed in the experiment. The radionuclide activities in the cements ranged from 8.58–19.1 Bq·kg−1, 9.78–26.3 Bq·kg−1 and 156.5–489.4 Bq·kg−1 for 226Ra, 232Th and 40K, respectively. The radiological parameters in cement samples were calculated as follows: mean radium equivalent activity Raeq = 67.87 Bq·kg−1, gamma index Iγ = 0.256, alpha index Iα = 0.067, the absorbed gamma dose rate D = 60.76 nGy·h−1, external hazard index Hex = 0.182 and internal hazard index Hin was 0.218. The radionuclide activity in composites ranged from 6.84–10.8 Bq·kg−1 for 226Ra, 13.1–20.5 Bq·kg−1 for 232Th and 250.4–494.4 Bq·kg−1 for 40K. The calculated radiological parameters of cements were lower than calculated radiological parameters of cement composites. PMID:24351739

  19. Assessment of natural radioactivity levels in soil samples from some areas in Assiut, Egypt.

    PubMed

    El-Gamal, Hany; Farid, M El-Azab; Abdel Mageed, A I; Hasabelnaby, M; Hassanien, Hassanien M

    2013-12-01

    The natural radioactivity of soil samples from Assiut city, Egypt, was studied. The activity concentrations of 28 samples were measured with a NaI(Tl) detector. The radioactivity concentrations of (226)Ra, (232)Th, and (40)K showed large variations, so the results were classified into two groups (A and B) to facilitate the interpretation of the results. Group A represents samples collected from different locations in Assiut and characterized by low activity concentrations with average values of 46.15 ± 9.69, 30.57 ± 4.90, and 553.14 ± 23.19 for (226)Ra, (232)Th, and (40)K, respectively. Group B represents samples mainly collected from the area around Assiut Thermal Power Plant and characterized by very high activity concentrations with average values of 3,803 ± 145, 1,782 ± 98, and 1,377 ± 78 for (226)Ra, (232)Th, and (40)K, respectively. In order to evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity (Raeq), the absorbed dose rate (D), the annual effective dose rate (E), the external hazard index (H ex), and the annual gonadal dose equivalent (AGDE) have been calculated and compared with the internationally approved values. For group A, the calculated averages of these parameters are in good agreement with the international recommended values except for the absorbed dose rate and the AGDE values which are slightly higher than the international recommended values. However, for group B, all obtained averages of these parameters are much higher by several orders of magnitude than the international recommended values. The present work provides a background of radioactivity concentrations in the soil of Assiut.

  20. Measurement of activity concentrations of natural radionuclides in the topsoil of IITA Ibadan by gamma-ray spectrometry.

    PubMed

    Okeyode, I C; Farai, I P

    2007-09-01

    The activity concentrations of the natural radionuclides in the soils at the International Institute of Tropical Agriculture, (IITA), Idi-Ose, Moniya, Ibadan, Nigeria were investigated using a NaI (Tl) scintillation detector coupled with a Canberra series 10 plus multichannel analyser as the detecting device for gamma scintillation spectroscopy. The whole area was divided into grids and soil samples were collected from the points of intersection of the grids. The average activity concentrations obtained for the three radionuclides (40K, 238U and 232Th) were 180.08 +/- 90.54 Bq kg(-1) for 40K, 8.901 +/- 5.063 Bq kg(-1) for 238U and 11.01 +/- 7.686 Bq kg(-1) for 232Th. The average values of the absorbed dose rate for each radionuclide were found to be 7.33 nGy h(-1) for 232Th, 7.55 nGy h(-1) for 40K and 3.82 nGy h(-1) for 238U. The average (baseline) of the total absorbed dose rate was found to be 18.72 +/- 8.11 nGy h(-1). The baseline average outdoor annual effective dose equivalent at IITA due to the concentrations of the radionuclides was found to be 22.95 +/- 9.94 microSv y(-1). This value is low compared to the world average of 70 microSv y(-1) specified by UNSCEAR for an outdoor effective dose. Hence the probability of occurrence of any of the health effects of radiation is low.

  1. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico

    PubMed Central

    Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

    2015-01-01

    Determining ionizing radiation in a geographic area serves to assess its effects on a population’s health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h−1. At the same sites, 48 soil samples were taken to obtain the activity concentrations of 226Ra, 232Th and 40K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h−1. Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg−1, for 226Ra, 232Th and 40K, respectively. From the analysis, the spatial distribution of 232Th, 226Ra and 40K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize. PMID:26437425

  2. Soil radioactivity levels, radiological maps and risk assessment for the state of Kuwait.

    PubMed

    Alazemi, N; Bajoga, A D; Bradley, D A; Regan, P H; Shams, H

    2016-07-01

    An evaluation of the radioactivity levels associated with naturally occurring radioactive materials has been undertaken as part of a systematic study to provide a surface radiological map of the State of Kuwait. Soil samples from across Kuwait were collected, measured and analysed in the current work. These evaluations provided soil activity concentration levels for primordial radionuclides, specifically members of the (238)U and (232)Th decay chains and (40)K which. The (238)U and (232)Th chain radionuclides and (40)K activity concentration values ranged between 5.9 ↔ 32.3, 3.5 ↔ 27.3, and 74 ↔ 698 Bq/kg respectively. The evaluated average specific activity concentrations of (238)U, (232)Th and (40)K across all of the soil samples have mean values of 18, 15 and 385 Bq/kg respectively, all falling below the worldwide mean values of 35, 40 and 400 Bq/kg respectively. The radiological risk factors are associated with a mean of 33.16 ± 2.46 nG/h and 68.5 ± 5.09 Bq/kg for the external dose rate and Radium equivalent respectively. The measured annual dose rates for all samples gives rise to a mean value of 40.8 ± 3.0 μSv/y while the internal and internal hazard indices have been found to be 0.23 ± 0.02 and 0.19 ± 0.01 respectively. PMID:27038900

  3. Study of environmental radioactivity in Palestine by in situ gamma-ray spectroscopy.

    PubMed

    Lahham, Adnan; Al-Masri, Hussein; Judeh, Adnan

    2009-07-01

    This work presents qualitative and quantitative evaluation of environmental radioactivity in the central and southern areas of the West Bank, Palestine. For this purpose, the technology of in situ gamma-ray spectroscopy is used with a scintillation of 7.6 x 7.6 cm NaI(Tl) crystal connected to multichannel analyzer InSpector 2000 from Canberra instruments and laptop computer. Gamma-ray spectra were collected using the detector placed 1 m above the ground surface. Calibration of the detection system for in situ measurements of gamma-emitting radionuclides in open terrain is performed theoretically using Monte Carlo techniques. Measurements are conducted in 18 locations in 3 regions across the West Bank. The vast majority of identified radionuclides are naturally occurring gamma-emitting sources (the decay products of (238)U, (232)Th and (40)K). The only identified anthropogenic radionuclide is (137)Cs. Activity concentrations of (40)K, (238)U, (232)Th as well as the total outdoor gamma dose rate from these radionuclides were determined from the gamma-ray spectra. The highest activity concentrations of the three primordial radionuclides were 203 Bq kg(-1) for (40)K, 32 Bq kg(-1) for (238)U and 30 Bq kg(-1) for (232)Th. The total outdoor gamma dose rate calculated for the whole study area at 1 m above ground ranged from 6 to 30 nGy h(-1) with a mean of 18 +/- 7 nGy h(-1), which represents about 30% of the world average value. PMID:19470444

  4. Environmental-Impact Assessment of Natural Radioactivity Around a Traditional Mining Area in Al-Ibedia, Sudan.

    PubMed

    Idriss, Hajo; Salih, Isam; Alaamer, Abdulaziz S; Saleh, Almuaiz; Abdelgali, M Y

    2016-05-01

    Recently, in the Sudan, traditional gold mining has been growing rapidly and has become a very attractive and popular economic activity. Mining activity is recognized as one of the sources of radioactivity contamination. Hence, the radioactivity concentration and radiological hazard due to exposure of radionuclides (226)Ra, (232)Th, and (40)K were evaluated. The measurements were performed using gamma-ray spectrometry with an NaI (Tl) detector. The results show that (226)Ra, (232)Th, and (40)K activity concentration ranged from 2.66 to 18.47, 9.20 to 51.87, and 0.17 to 419.77 Bq/kg with average values of 7.54 ± 4.91, 20.74 ± 11.29, and 111.87 ± 136.84 Bq/kg, respectively. In contrast, (222)Rn in soil, (222)Rn in air, and (226)Ra in vegetables along with radiation dose were computed and compared with the international recommended levels. Potential radiological effects to miners and the public due to (226)Ra, (232)Th, (40)K, and (222)Rn are insignificant. (226)Ra transferred to vegetables appears to be negligible compared with the allowable limit 1.0 mSv/year set by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The average value of the annual gonadal dose equivalent (AGDE) is lower than the global average of 300 µSv/year (UNSCEAR 2000). However, some locations exhibit values >300 µSv/year. To the best of our knowledge, so far there seems to be no data regarding radioactivity monitoring in traditional mining areas in the Sudan.

  5. Natural radioactivity levels and heavy metals in chemical and organic fertilizers used in Kingdom of Saudi Arabia.

    PubMed

    El-Taher, A; Althoyaib, S S

    2012-01-01

    The present work deals with identifying and determining the activity levels of natural occuring radionuclides, (226)Ra and (232)Th series, their decay products and (40)K, in chemical and organic fertilizers used in Kingdom of Saudi Arabia. A total of 30 samples: 20 phosphatic fertilizers (single super-phosphate SSP and triple super-phosphate,TSP) and 10 organic fertilizers (cow, sheep and chicken) collected from markets and farms. The gamma-ray spectrometer consists of NaI(Tl) detector and its electronic circuit was used for measuring γ-ray spectra. The ranges of radioactivity levels of (226)Ra, (232)Th and (40)K in chemical fertilizers are 51.5±5.2-106.3±7.5, 5.1±1.6-9.9±3.2. and 462.6±21-607.3±14Bqkg(-1), respectively. The activities of (226)Ra, (232)Th and (40)K in natural fertilizers (cow, sheep and chicken) are lower than the activities in chemical fertilizers. The obtained data are compared with available reported data from other countries in literature. The Ra(eq) in chemical fertilizer ranges from 100.37 to 161.43Bqkg(-1) and in organic fertilizer ranges from 34.07 to 102.19Bqkg(-1), which are lower than the limit of 370Bqkg(-1) adopted from NEA-OECD (1979). The average heavy metal (Pb, Cd, Ni, Co and Cr) contents of the fertilizers marketed in the Kingdom of Saudi Arabia are also determined and within the limits of those used worldwide.

  6. Soil radioactivity levels, radiological maps and risk assessment for the state of Kuwait.

    PubMed

    Alazemi, N; Bajoga, A D; Bradley, D A; Regan, P H; Shams, H

    2016-07-01

    An evaluation of the radioactivity levels associated with naturally occurring radioactive materials has been undertaken as part of a systematic study to provide a surface radiological map of the State of Kuwait. Soil samples from across Kuwait were collected, measured and analysed in the current work. These evaluations provided soil activity concentration levels for primordial radionuclides, specifically members of the (238)U and (232)Th decay chains and (40)K which. The (238)U and (232)Th chain radionuclides and (40)K activity concentration values ranged between 5.9 ↔ 32.3, 3.5 ↔ 27.3, and 74 ↔ 698 Bq/kg respectively. The evaluated average specific activity concentrations of (238)U, (232)Th and (40)K across all of the soil samples have mean values of 18, 15 and 385 Bq/kg respectively, all falling below the worldwide mean values of 35, 40 and 400 Bq/kg respectively. The radiological risk factors are associated with a mean of 33.16 ± 2.46 nG/h and 68.5 ± 5.09 Bq/kg for the external dose rate and Radium equivalent respectively. The measured annual dose rates for all samples gives rise to a mean value of 40.8 ± 3.0 μSv/y while the internal and internal hazard indices have been found to be 0.23 ± 0.02 and 0.19 ± 0.01 respectively.

  7. Escaping radioactivity from coal-fired power plants (CPPs) due to coal burning and the associated hazards: a review.

    PubMed

    Papastefanou, Constantin

    2010-03-01

    Coal, like most materials found in nature, contains trace quantities of the naturally occurring primordial radionuclides, i.e. of (40)K and of (238)U, (232)Th and their decay products. Therefore, the combustion of coal results in the released into the environment of some natural radioactivity (1.48 TBq y(-1)), the major part of which (99%) escapes as very fine particles, while the rest in fly ash. The activity concentrations of natural radionuclides measured in coals originated from coal mines in Greece varied from 117 to 435 Bq kg(-1) for (238)U, from 44 to 255 Bq kg(-1) for (226)Ra, from 59 to 205 Bq kg(-1) for (210)Pb, from 9 to 41 Bq kg(-1) for (228)Ra ((232)Th) and from 59 to 227 Bq kg(-1) for (40)K. Fly ash escapes from the stacks of coal-fired power plants in a percentage of 3-1% of the total fly ash, in the better case. The natural radionuclide concentrations measured in fly ash produced and retained or escaped from coal-fired power plants in Greece varied from 263 to 950 Bq kg(-1) for (238)U, from 142 to 605 Bq kg(-1) for (226)Ra, from 133 to 428 Bq kg(-1) for (210)Pb, from 27 to 68 Bq kg(-1) for (228)Ra ((232)Th) and from 204 to 382 Bq kg(-1) for (40)K. About 5% of the total ash produced in the coal-fired power plants is used as substitute of cement in concrete for the construction of dwellings, and may affect indoor radiation doses from external irradiation and the inhalation of radon decay products (internal irradiation) is the most significant. The resulting normalized collective effective doses were 6 and 0.5man-Sv(GWa)(-1) for typical old and modern coal-fired power plants, respectively.

  8. Assessment of radionuclides and heavy metals in marine sediments along the Upper Gulf of Thailand

    NASA Astrophysics Data System (ADS)

    Khuntong, S.; Phaophang, C.; Sudprasert, W.

    2015-05-01

    Due to the Fukushima Daiichi nuclear disaster in 2011 and the development of nuclear power plant in neighboring countries such as Vietnam in the near future, radionuclide assessment in marine sediment during 2010 - 2011 may be useful as background levels for radiation protection in Thailand. Marine sediments (10 samples) were collected approximately 1 km away from the coastline along Chonburi to Pattaya, Chonburi Province. The sediments were ground and sieved through 2-mm test sieve after air drying. Radionuclides were measured with a gamma spectrometer equipped with a well-calibrated HPGe detector. The samples were prepared in the same geometry as the reference material. The optimal counting time was 60,000 - 80,000 s for statistical evaluation and uncertainties. No contamination of 137Cs as an artificial radionuclide was found. Naturally-occurring radionuclides including 238U, 232Th and 40K were found. The mean specific activities of 238U, 232Th and 40K were 44 ± 10, 59 ± 17 and 463 ± 94 Bq/kg in the rainy season (2010); 41 ± 6, 50 ± 9 and 484 ± 83 Bq/kg in the winter (2010), and 39 ± 6, 41 ± 7 and 472 ± 81 Bq/kg in the summer (2011), respectively. The mean specific activities were higher than the values in the UNSCEAR report of 35, 30 and 400 Bq/kg for 238U, 232Th and 40K, respectively. From the measured specific activities, the absorbed dose rate, radium equivalent activity, external hazard index and annual external effective dose rate were calculated in order to assess the health risk. No radiation hazards related to the radioactivity in the sediment were expected. The accumulation of radionuclides varied with the particle size and the organic matter content in the sediment. The accumulation of heavy metals showed similar results to that of the radionuclides in the sediment.

  9. Measurement of gamma radiation levels in soil samples from Thanjavur using γ-ray spectrometry and estimation of population exposure

    PubMed Central

    Senthilkumar, B.; Dhavamani, V.; Ramkumar, S.; Philominathan, P.

    2010-01-01

    This study assesses the level of terrestrial gamma radiation and associated dose rates from the naturally occurring radionuclides 232Th, 238U and 40K in 10 soil samples collected from Thanjavur (Tamil Nadu, India) using γ-ray spectrometry. The activity profile of radionuclides has clearly showed the existence of low level activity in Thanjavur. The geometric mean activity concentrations of 232Th, 238U and 40K is 42.9±9.4 Bq.kg−1, 14.7±1.7 Bq.kg−1 and 149.5±3.1 Bq.kg−1 respectively are derived from all the soil samples studied. The activity concentration of 232Th, 238U and 40K in soil is due to the presence of metamorphic rocks like shale, hornblende-biotite gneiss and quartzofeldspathic gneiss in these areas. Gamma absorbed dose rates in air outdoors were calculated to be in the range between 32 nGy.h−1 and 59.1 nGy.h−1 with an arithmetic mean of 43.3 ±9 nGy.h−1. This value is lesser than the population weighted world-averaged of 60 nGy.h−1. Inhabitants of Thanjavur are subjected to external gamma radiation exposure (effective dose) ranging between 39.2 and 72.6 μSv.y−1 with an arithmetic mean of 53.1±11 μSv.y−1. The values of the external hazard index determined from the soil radioactivity of the study area are less than the recommended safe levels. PMID:20177570

  10. Doses of external exposure in Jordan house due to gamma-emitting natural radionuclides in building materials.

    PubMed

    Al-Jundi, J; Ulanovsky, A; Pröhl, G

    2009-10-01

    The use of building materials containing naturally occurring radionuclides as (40)K, (232)Th, and (238)U and their progeny results in external exposures of the residents of such buildings. In the present study, indoor dose rates for a typical Jordan concrete room are calculated using Monte Carlo method. Uniform chemical composition of the walls, floor and ceiling as well as uniform mass concentrations of the radionuclides in walls, floor and ceiling are assumed. Using activity concentrations of natural radionuclides typical for the Jordan houses and assuming them to be in secular equilibrium with their progeny, the maximum annual effective doses are estimated to be 0.16, 0.12 and 0.22 mSv a(-1) for (40)K, (232)Th- and (238)U-series, respectively. In a total, the maximum annual effective indoor dose due to external gamma-radiation is 0.50 mSv a(-1). Additionally, organ dose coefficients are calculated for all organs considered in ICRP Publication 74. Breast, skin and eye lenses have the maximum equivalent dose rate values due to indoor exposures caused by the natural radionuclides, while equivalent dose rates for uterus, colon (LLI) and small intestine are found to be the smallest. More specifically, organ dose rates (nSv a(-1)per Bq kg(-1)) vary from 0.044 to 0.060 for (40)K, from 0.44 to 0.60 for radionuclides from (238)U-series and from 0.60 to 0.81 for radionuclides from (232)Th-series. The obtained organ and effective dose conversion coefficients can be conveniently used in practical dose assessment tasks for the rooms of similar geometry and varying activity concentrations and local-specific occupancy factors. PMID:19628312

  11. Daily intakes of naturally occurring radioisotopes in typical Korean foods.

    PubMed

    Choi, Min-Seok; Lin, Xiu-Jing; Lee, Sun Ah; Kim, Wan; Kang, Hee-Dong; Doh, Sih-Hong; Kim, Do-Sung; Lee, Dong-Myung

    2008-08-01

    The concentrations of naturally occurring radioisotopes ((232)Th, (228)Th, (230)Th, (228)Ra, (226)Ra, and (40)K) in typical Korean foods were evaluated. The daily intakes of these radioisotopes were calculated by comparing concentrations in typical Korean foods and the daily consumption rates of these foods. Daily intakes were as follows: (232)Th, 0.00-0.23; (228)Th, 0.00-2.04; (230)Th, 0.00-0.26; (228)Ra, 0.02-2.73; (226)Ra, 0.01-4.37 mBq/day; and (40)K, 0.01-5.71 Bq/day. The total daily intake of the naturally occurring radioisotopes measured in this study from food was 39.46 Bq/day. The total annual internal dose resulting from ingestion of radioisotopes in food was 109.83 muSv/y, and the radioisotope with the highest daily intake was (40)K. These values were same level compiled in other countries.

  12. Natural Radioactivity In Poultry Rations And DCP For Bovine Nutrition

    NASA Astrophysics Data System (ADS)

    Luz-Filho, Isaias V.; Scheibel, Viviane; Appoloni, Carlos R.

    2011-08-01

    The aim of this study is to determine the level of radioactivity present in samples of poultry rations and dicalcium phosphate (DCP) used for cattle feed. Knowledge of these levels is of fundamental importance, because part of this radioactivity will possibly be transferred to humans. The radiation found in such samples is due to the presence of radioactive series of 238U and 232Th and 40K. Measurements were performed with a 66% HPGe detector at the Laboratory of Applied Nuclear Physics, State University of Londrina. The measured samples were commercialized in Londrina, Brazil, in the second half of 2007. The accommodation recipient of the samples was a 1 L Marinelli beaker. Poultry rations were divided into two types: for young chickens and adult chickens. Among these, the ration for adult chickens showed the highest values for the activities of 226Ra and 228Ra, 0.23±0.17 and 0.493±0.091 Bq/kg respectively. But the ration for young chickens showed the highest activity for the 40K, 304±15 Bq/kg. The DCP sample showed a much higher value for the series of 238U and 232Th, 83±26 and 7.79±0.70 Bq/kg, respectively. However, the 40K activity in this sample was about 5 or 6 times lower than samples for poultry feed, reaching 46.6±2.8 Bq/kg.

  13. Environmental radionuclides in a coastal wetland of the Southern Laizhou Bay, China.

    PubMed

    Wang, Qidong; Song, Jinming; Li, Xuegang; Yuan, Huamao; Li, Ning; Cao, Lei

    2015-08-15

    The radioactivity concentration of (238)U, (232)Th, (226)Ra, (40)K, and (137)Cs in soil samples collected in a coastal wetland of the Southern Laizhou Bay, China were measured. Mean activity concentrations were 54.4±11.7, 57.9±9.7, 28.6±4.3, 542±21, and 10.2±2.9Bqkg(-1) dry weight for (238)U, (232)Th, (226)Ra, (40)K and (137)Cs, respectively. Statistical analyses suggested significant correlations between clay content and (40)K as well as (137)Cs. The radium equivalent activity, the absorbed dose rate in the air at 1m above the ground surface, and the external hazard index were calculated. The result showed that the radioactivity level in the wetland was in normal range. But sites along the river tended to have higher radiological hazard indexes. The vertical distributions of radionuclides in profiles illustrated some phenomena, such as vertical transport of (238)U, disequilibrium between (238)U and (226)Ra, and change in material sources.

  14. Radioactivity levels and heavy metals in the urban soil of Central Serbia.

    PubMed

    Milenkovic, B; Stajic, J M; Gulan, Lj; Zeremski, T; Nikezic, D

    2015-11-01

    Radioactivity concentrations and heavy metal content were measured in soil samples collected from the area of Kragujevac, one of the largest cities in Serbia. The specific activities of (226)Ra, (232)Th, (40)K and (137)Cs in 30 samples were measured by gamma spectrometry using an HPGe semiconductor detector. The average values ± standard deviations were 33.5 ± 8.2, 50.3 ± 10.6, 425.8 ± 75.7 and 40.2 ± 26.3 Bq kg(-1), respectively. The activity concentrations of (226)Ra, (232)Th and (137)Cs have shown normal distribution. The annual effective doses, radium equivalent activities, external hazard indexes and excess lifetime cancer risk were also estimated. A RAD7 device was used for measuring radon exhalation rates from several samples with highest content of (226)Ra. The concentrations of As, Co, Cr, Cu, Mn, Ni, Pb and Zn were measured, as well as their EDTA extractable concentrations. Wide ranges of values were obtained, especially for Cr, Mn, Ni, Pb and Zn. The absence of normal distribution indicates anthropogenic origin of Cr, Ni, Pb and Zn. Correlations between radionuclide activities, heavy metal contents and physicochemical properties of analysed soil were determined by Spearman correlation coefficient. Strong positive correlation between (226)Ra and (232)Th was found.

  15. Natural radioactivity distribution and gamma radiation exposure of beach sands close to Kavala pluton, Greece

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Argyrios; Koroneos, Antonios; Christofides, Georgios; Stoulos, Stylianos

    2015-10-01

    This study aims to evaluate the activity concentrations of 238U, 226Ra, 232Th, 228Th and 40K along the beaches of Kavala being adjacent to the rock-types of the Kavala pluton. These ranged from 14-940, 16-1710, 26- 4547, 27-4488 and 194-1307 Bq/kg respectively, representing the highest values of natural radioactivity measured in sediments of Greece. The (%wt.) heavy magnetic (HM) (allanite, amphibole, mica, clinopyroxene, magnetite and hematite) fraction, the heavy non-magnetic (HNM) (monazite, zircon, titanite and apatite) fraction and the total heavy fraction (TH), were correlated with the concentrations of the measured radionuclides in the bulk samples. The heavy fractions seem to control the activity concentrations of 238U and 232Th of all the samples, showing some local differences in the main 238U and 232Th mineral carrier. The measured radionuclides in the beach sands were normalized to the respective values measured in the granitic rocks, which are their most probable parental rocks, so as to provide data upon their enrichment or depletion. The annual equivalent dose varies between 0.01 and 0.35 mSv y-1 for tourists and from 0.03 to 1.48 mSv y-1 for local people working on the beach.

  16. Natural radioactivity in cultivated land in the vicinity of a phosphate fertilizer plant in Nigeria

    NASA Astrophysics Data System (ADS)

    Okeji, Mark C.; Agwu, Kenneth K.; Idigo, Felicitas U.

    2012-12-01

    Natural radioactivity in soil and vegetable samples in cultivated land in the vicinity of an active phosphate fertilizer plant in Kaduna, Nigeria was carried out to assess the potential radiological impact of the plant on its immediate environment. The activity counting was carried out using sodium iodide gamma spectrometry. The annual committed effective dose for two vegetables in the farmlands due to uranium (238U) and thorium (232Th) was assessed. The mean activity concentration of radionuclides in the soil samples ranges from 20.5±7.3 to 31.6±4.1 Bq kg-1 for 226Ra, 19.6±1.6 to 53.2±3.7 Bq kg-1 for 232Th and 203.9±6.3 to 253.6±9.5 Bq kg-1 for 40K. The annual intake of 238U and 232Th from consumption of okra were 1.9 Bq kg-1 and 5.22 Bq kg-1 and for tomatoes 2.66 Bq kg-1 and 5.1 Bq kg-1 respectively. The committed effective doses from consumption of okra and tomatoes were 0.1 μSv y-1 and 0.12 μSv y-1 respectively.

  17. Natural Gamma Emitters after a Selective Chemical Separation of a TENORM residue: Preliminary Results

    SciTech Connect

    Alves de Freitas, Antonio; Abrao, Alcidio; Godoy dos Santos, Adir Janete; Pecequilo, Brigitte Roxana Soreanu

    2008-08-07

    An analytical procedure was established in order to obtain selective fractions containing radium isotopes ({sup 228}Ra), thorium ({sup 232}Th), and rare earths from RETOTER (REsiduo de TOrio e TErras Raras), a solid residue rich in rare earth elements, thorium isotopes and small amount of natural uranium generated from the operation of a thorium pilot plant for purification and production of pure thorium nitrate at IPEN -CNEN/SP. The paper presents preliminary results of {sup 228}Ra, {sup 226}Ra, {sup 238}U, {sup 210}Pb, and {sup 40}K concentrations in the selective fractions and total residue determined by high-resolution gamma spectroscopy, considering radioactive equilibrium of the samples.

  18. Absorbed Gamma-Ray Doses due to Natural Radionuclides in Building Materials

    SciTech Connect

    Aguiar, Vitor A. P.; Medina, Nilberto H.; Moreira, Ramon H.; Silveira, Marcilei A. G.

    2010-05-21

    This work is devoted to the application of high-resolution gamma-ray spectrometry in the study of the effective dose coming from naturally occurring radionuclides, namely {sup 40}K, {sup 232}Th and {sup 238}U, present in building materials such as sand, cement, and granitic gravel. Four models were applied to estimate the effective dose and the hazard indices. The maximum estimated effective dose coming from the three reference rooms considered is 0.90(45) mSv/yr, and maximum internal hazard index is 0.77(24), both for the compact clay brick reference room. The principal gamma radiation sources are cement, sand and bricks.

  19. Absorbed Gamma-Ray Doses due to Natural Radionuclides in Building Materials

    NASA Astrophysics Data System (ADS)

    Aguiar, Vitor A. P.; Medina, Nilberto H.; Moreira, Ramon H.; Silveira, Marcilei A. G.

    2010-05-01

    This work is devoted to the application of high-resolution gamma-ray spectrometry in the study of the effective dose coming from naturally occurring radionuclides, namely 40K, 232Th and 238U, present in building materials such as sand, cement, and granitic gravel. Four models were applied to estimate the effective dose and the hazard indices. The maximum estimated effective dose coming from the three reference rooms considered is 0.90(45) mSv/yr, and maximum internal hazard index is 0.77(24), both for the compact clay brick reference room. The principal gamma radiation sources are cement, sand and bricks.

  20. Natural radioactivity measurements in building materials used in Samsun, Turkey.

    PubMed

    Tufan, M Çagatay; Disci, Tugba

    2013-01-01

    In this study, radioactivity levels of 35 different samples of 11 commonly used building materials in Samsun were measured by using a gamma spectrometry system. The analysis carried out with the high purity Germanium gamma spectrometry system. Radioactivity concentrations of (226)Ra, (232)Th and (40)K range from 6 to 54 Bq kg(-1), 5 to 88 Bq kg(-1) and 6 to 1070 Bq kg(-1), respectively. From these results, radium equivalent activities, gamma indexes, absorbed dose rates and annual effective doses were calculated for all samples. Obtained results were compared with the available data, and it was concluded that all the investigated materials did not have radiological risk.

  1. Environmental Radioactivity Study in Surface Sediments of Guacanayabo Gulf (Cuba)

    SciTech Connect

    Reyes, H.; Rizo, O. Diaz; Bernal, J. L.; D'Alessandro, K.; Padilla, F.; Corrales, Y.; Casanova, O. A.; Gelen, A.; Martinez, Y.; Aguilar, J.; Arado, J. O.; Lopez-Pino, N.; Maidana, N. L.

    2009-06-03

    Sediment samples have been collected in the Guacanayabo gulf located in the southeast Cuba, to determinate the radioactivity levels of {sup 210}Pb, {sup 234}Th, {sup 214}Pb, {sup 137}Cs, {sup 232}Th and {sup 40}K using Low-Background Gamma Spectrometry and to evaluate its impact in the habitat of important marine species for fishery industry. The obtained results show the lowest radioactivity levels determined in Cuban marine environments. The species capture declination in the last years is not originated by radioactive pollution of the zone.

  2. Occupational exposure due to naturally occurring radionuclide material in granite quarry industry.

    PubMed

    Ademola, J A

    2012-02-01

    The potential occupational exposure in granite quarry industry due to the presence of naturally occurring radioactive material (NORM) has been investigated. The activity concentrations of (40)K, (226)Ra and (232)Th were determined using gamma-ray spectroscopy method. The annual effective dose of workers through different exposure pathways was determined by model calculations. The total annual effective dose varied from 21.48 to 33.69 μSv y(-1). Inhalation dose contributes the highest to the total effective dose. The results obtained were much lower than the intervention exemption levels (1.0 mSv y(-1)) given in the International Commission on Radiological Protection Publication 82.

  3. Determination of naturally occurring radionuclides in soil samples of Ayranci, Turkey

    NASA Astrophysics Data System (ADS)

    Agar, Osman; Eke, Canel; Boztosun, Ismail; Emin Korkmaz, M.

    2015-04-01

    The specific activity, radiation hazard index and the annual effective dose of the naturally occurring radioactive elements (238U, 232Th and 40K) were determined in soil samples collected from 12 different locations in Ayranci region by using a NaI(Tl) gamma-ray spectrometer. The measured activity concentrations of the natural radionuclides in studied soil samples were compared with the corresponding results of different countries and the internationally reported values. From the analysis, it is found that these materials may be safely used as construction materials and do not pose significant radiation hazards.

  4. Estimation of heat generation by radioactive decay of some phosphate rocks in Egypt.

    PubMed

    Din, Khaled Salahel

    2009-11-01

    Radiogenic heat production data for phosphate rocks outcropping on the three main areas Eastern Desert, Western Desert and Nile Valley are presented. They were derived from uranium, thorium and potassium concentration measurements of gamma radiation originating from the decay of (214)Bi ((238)U series), (208)Tl ((232)Th series) and the primary decay of (40)K. A low radioactive heat production rate (0.32+/-0.1 microWm(-3)) was found for Wadi Hegaza, whereas the highest value (19+/-4.1 microWm(-3)) was found for Gabel Anz, Eastern Desert of Egypt.

  5. Calculation of the effective dose from natural radioactivity in soil using MCNP code.

    PubMed

    Krstic, D; Nikezic, D

    2010-01-01

    Effective dose delivered by photon emitted from natural radioactivity in soil was calculated in this work. Calculations have been done for the most common natural radionuclides in soil (238)U, (232)Th series and (40)K. A ORNL human phantoms and the Monte Carlo transport code MCNP-4B were employed to calculate the energy deposited in all organs. The effective dose was calculated according to ICRP 74 recommendations. Conversion factors of effective dose per air kerma were determined. Results obtained here were compared with other authors. PMID:20045343

  6. Radiation doses to members of the U.S. population from ubiquitous radionuclides in the body: Part 3, results, variability, and uncertainty.

    PubMed

    Watson, David J; Strom, Daniel J

    2011-04-01

    This paper is Part 3 of a three-part series investigating effective dose rates to residents of the United States from intakes of ubiquitous radionuclides, including radionuclides occurring naturally, radionuclides whose concentrations are technologically enhanced, and anthropogenic radionuclides. The radionuclides of interest are the (238)U series (14 nuclides), the actinium series (headed by (235)U; 11 nuclides), and the (232)Th series (11 nuclides); primordial radionuclides (87)Rb and (40)K; cosmogenic and fallout radionuclides (14)C and (3)H; and purely anthropogenic radionuclides (137)Cs-(137m)Ba, (129)I and (90)Sr-(90)Y. This series of papers explicitly excludes intakes from inhaling (222)Rn, (220)Rn, and their short-lived decay products; it also excludes intakes of radionuclides in occupational and medical settings. In this work, it is assumed that instantaneous dose rates in target organs are proportional to steady-state radionuclide concentrations in source regions. Part 1 reviewed, summarized, characterized, and grouped all published and some unpublished data for U.S. residents on ubiquitous radionuclide concentrations in tissues and organs. Part 2 described the methods used to organize the data collected in Part 1 and segregate it into the ages and genders defined by the study, including imputed missing values from the existing data, apportioned activity in bone, and imputed activity in hollow organ contents and the remainder of the body. This paper estimates equivalent dose rates to target tissues from source regions and maps target tissues to lists of tissues with International Commission on Radiation Protection (ICRP) tissue-weighting factors or to surrogate tissue regions when there is no direct match. Effective dose rates using ICRP tissue-weighting factors recommended in 1977, 1990, and 2007, are then calculated, and an upper bound of variability of the effective dose rate is estimated by calculating the average coefficients of variation (CV

  7. Mantle convection and the distribution of geochemical reservoirs in the silicate shell of the Earth

    NASA Astrophysics Data System (ADS)

    Walzer, Uwe; Hendel, Roland

    2010-05-01

    We present a dynamic 3-D spherical-shell model of mantle convection and the evolution of the chemical reservoirs of the Earth`s silicate shell. Chemical differentiation, convection, stirring and thermal evolution constitute an inseparable dynamic system. Our model is based on the solution of the balance equations of mass, momentum, energy, angular momentum, and four sums of the number of atoms of the pairs 238U-206Pb, 235U-207Pb, 232Th-208Pb, and 40K-40Ar. Similar to the present model, the continental crust of the real Earth was not produced entirely at the start of the evolution but developed episodically in batches [1-7]. The details of the continental distribution of the model are largely stochastic, but the spectral properties are quite similar to the present real Earth. The calculated Figures reveal that the modeled present-day mantle has no chemical stratification but we find a marble-cake structure. If we compare the observational results of the present-day proportion of depleted MORB mantle with the model then we find a similar order of magnitude. The MORB source dominates under the lithosphere. In our model, there are nowhere pure unblended reservoirs in the mantle. It is, however, remarkable that, in spite of 4500 Ma of solid-state mantle convection, certain strong concentrations of distributed chemical reservoirs continue to persist in certain volumes, although without sharp abundance boundaries. We deal with the question of predictable and stochastic portions of the phenomena. Although the convective flow patterns and the chemical differentiation of oceanic plateaus are coupled, the evolution of time-dependent Rayleigh number, Rat , is relatively well predictable and the stochastic parts of the Rat(t)-curves are small. Regarding the juvenile growth rates of the total mass of the continents, predictions are possible only in the first epoch of the evolution. Later on, the distribution of the continental-growth episodes is increasingly stochastic

  8. The History of Planetary Degassing as Recorded by Noble Gases

    NASA Astrophysics Data System (ADS)

    Porcelli, D.; Turekian, K. K.

    2003-12-01

    solid Earth, and the half-lives of the major parental nuclides, are given in Table 1. Table 1. Major nuclear processes producing noble-gas isotopes in the solid earth.a DaughterNuclear processParent half-lifeYield (atoms/decay)Comments 3He6Li(n, α)3H(β-)3He3He/4He=1×10-8b 4Heα-decay of 238U decay series nuclides4.468 Ga8c 4Heα-decay of 235U decay series nuclides0.7038 Ga7c238U/235U=137.88 4Heα-decay of 232Th decay series nuclides14.01 Ga6cTh/U=3.8 in bulk Earth 21Ne18O(α, n)21Ne21Ne/4He=4.5×10-8b 21Ne24Mg(n, α)21Ne21Ne/4He=1×10-10b 40Ar40K β- decay1.251 Ga0.1048b40K=0.01167% total K 129Xe129I β- decay15.7 Ma1129I/127I=1.1×10-4 at 4.56 Gad 136Xe238U spontaneous fission4×10-8e 136Xe244Pu spontaneous fission80.0 Ma7.00×10-5244Pu/238U=6.8×10-3 at 4.56 Gaf a From data compilations of Blum (1995), Ozima and Podosek (2001), and Pfennig et al. (1998).b Production ratio for upper crust (Ballentine and Burnard, 2002).c Per decay of series parent, assuming secular equilibrium for entire decay series.d Hohenberg et al. (1967).e Eikenberg et al. (1993) and Ragettli et al. (1994).f Hudson et al.(1989).

  9. Natural radioactivity contents in tobacco and radiation dose induced from smoking.

    PubMed

    Shousha, Hany A; Ahmad, Fawzia

    2012-06-01

    One of the causative factors for cancer-inducing mechanisms in humans is radioactive elements present in tobacco leaves used in the manufacture of cigarettes. Smoking of tobacco and its products increases the internal intake and radiation dose due to naturally occurring radionuclides that are considered to be one of the most significant causes of lung cancer. In this work, different commercial types of cigarettes, cigar and moassel were collected from market. Naturally occurring radionuclides (226)Ra and (214)Bi ((238)U series), (228)Ac and (228)Ra ((232)Th series), (40)K  and man-made (137)Cs were measured in tobacco using gamma-ray spectrometer. Results show that the average concentrations of (238)U, (232)Th and (40)K were 4.564, 3.940 and 1289.53 Bq kg(-1), respectively. This reflects their origin from the soil by root uptake and fertilisers used in the cultivation of tobacco plants. Concentration of (137)Cs was 0.348 Bq kg(-1) due to root uptake or deposition onto the leaf foliage. For smokers, the annual effective dose due to inhalation of (238)U varied from 49.35 to 139.40 μSv(-1) (average 104.27 μSv y(-1)), while of (232)Th from 23.86 to 111.06 μSv y(-1) (average 65.52 μSv y(-1)). The annual effective dose resulting from (137)Cs was varied from 10.96 to 24.01 nSv y(-1) (average 19.41 nSv y(-1)).

  10. Role of light and heavy minerals on natural radioactivity level of high background radiation area, Kerala, India.

    PubMed

    Ramasamy, V; Sundarrajan, M; Suresh, G; Paramasivam, K; Meenakshisundaram, V

    2014-02-01

    Natural radionuclides ((238)U, (232)Th and (40)K) concentrations and eight different radiological parameters have been analyzed for the beach sediments of Kerala with an aim of evaluating the radiation hazards. Activity concentrations ((238)U and (232)Th) and all the radiological parameters in most of the sites have higher values than recommended values. The Kerala beach sediments pose significant radiological threat to the people living in the area and tourists going to the beaches for recreation or to the sailors and fishermen involved in their activities in the study area. In order to know the light mineral characterization of the present sediments, mineralogical analysis has been carried out using Fourier transform infrared (FTIR) spectroscopic technique. The eight different minerals are identified and they are characterized. Among the various observed minerals, the minerals such as quartz, microcline feldspar, kaolinite and calcite are major minerals. The relative distribution of major minerals is determined by calculating extinction co-efficient and the values show that the amount of quartz is higher than calcite and much higher than microcline feldspar. Crystallinity index is calculated to know the crystalline nature of quartz present in the sediments. Heavy mineral separation analysis has been carried out to know the total heavy mineral (THM) percentage. This analysis revealed the presence of nine heavy minerals. The minerals such as monazite, zircon, magnetite and illmenite are predominant. Due to the rapid and extreme changes occur in highly dynamic environments of sandy beaches, quantities of major light and heavy minerals are widely varied from site to site. Granulometric analysis shows that the sand is major content. Multivariate statistical (Pearson correlation, cluster and factor) analysis has been carried out to know the effect of mineralogy on radionuclide concentrations. The present study concluded that heavy minerals induce the (238)U and (232)Th

  11. Investigation of background radiation levels and geologic unit profiles in Durango, Colorado

    SciTech Connect

    Triplett, G.H. ); Foutz, W.L.; Lesperance, L.R. )

    1989-11-01

    As part of the Uranium Mill Tailings Remedial Action (UMTRA) Project, Oak Ridge National Laboratory (ORNL) has performed radiological surveys on 435 vicinity properties (VPs) in the Durango area. This study was undertaken to establish the background radiation levels and geologic unit profiles in the Durango VP area. During the months of May through June, 1986, extensive radiometric measurements and surface soil samples were collected in the Durango VP area by personnel from ORNL's Grand Junction Office. A majority of the Durango VP surveys were conducted at sites underlain by Quaternary alluvium, older Quaternary gravels, and Cretaceous Lewis and Mancos shales. These four geologic units were selected to be evaluated. The data indicated no formation anomalies and established regional background radiation levels. Durango background radionuclide concentrations in surface soil were determined to be 20.3 {plus minus} 3.4 pCi/g for {sup 40}K, 1.6 {plus minus} 0.5 pCi/g for {sup 226}Ra, and 1.2 {plus minus} 0.3 pCi/g for {sup 232}Th. The Durango background gamma exposure rate was found to be 16.5 {plus minus} 1.3 {mu}R/h. Average gamma spectral count rate measurements for {sup 40}K, {sup 226}Ra and {sup 232}Th were determined to be 553, 150, and 98 counts per minute (cpm), respectively. Geologic unit profiles and Durango background radiation measurements are presented and compared with other areas. 19 refs., 15 figs., 5 tabs.

  12. Radioactivity measurement of primordial radionuclides in and dose evaluation from marble and glazed tiles used as covering building materials in Turkey.

    PubMed

    Turhan, Ş; Varinlioğlu, A

    2012-09-01

    Measurements of the natural radioactivity arising from primordial radionuclides ((226)Ra, (232)Th and (40)K) in marble and glazed tile samples used covering building materials in Turkey were carried out by gamma-ray spectrometer with a high purity germanium detector. The mean activity concentrations of the (226)Ra, (232)Th and (40)K in marble and glazed tile samples were found as 8.2, 5.5 and 58.1 Bq kg(-1) and 81.2, 65.4 and 450.1 Bq kg(-1), respectively. The radiation doses received by occupants of buildings in which the sample marble and glazed tiles might be used are estimated using measured activity concentrations of constituent primordial radionuclides and dose conversion factors evaluated by the European Commission from models of tile use. Results obtained are presented for each radionuclide, analysed and compared with relevant national and international legislation, guidance and report, and with the results obtained from other studies. Results show that the use of such decorative building materials in the construction of domestic homes or workplaces in Turkey is unlikely to lead to any significant radiation exposure to the occupants.

  13. Radiation dose to Malaysian infants from natural radionuclides via consumption of powdered milk

    NASA Astrophysics Data System (ADS)

    Uwatse, Onosohwo Bemigho; Olatunji, Michael Adekunle; Khandaker, Mayeen Uddin; Amin, Yusoff Mohd.

    2015-04-01

    Milk is the basic food stuff for the infants because they generally consume more milk on a daily basis as its minerals and proteins are essential for their growth and development, therefore, it is very important to assess the natural radioactivity levels and the associated dose in the widely consumed powered infant's milk. As a result, 14 brands of infant's powdered milk were collected from different supermarkets around Selangor, Malaysia and analysed for 226Ra, 232Th and 40K activities. The obtained mean activity of 226Ra, 232Th and 40K are 3.05±1.84, 2.55±2.48 and 99.1±69.5 Bqkg-1, respectively. Among the analysed milk samples, the brand from Philippines (Lactogen) showed low level of radioactivity while Singaporean brand (S26 SMA Gold) showed the highest. The estimated mean annual effective doses due to the ingestion of natural radionuclides in the sampled milk are 635 and 111 µSv for infant ≤ 1y and infant 1-2y, respectively. The obtained dose value does not yet pose any significant radiological hazards to the population under investigation comparing with the 1.0 mSvy-1 recommended by ICRP for all ages.

  14. Measurement of natural radioactivity in Jordanian building materials and their contribution to the public indoor gamma dose rate.

    PubMed

    Sharaf, J M; Hamideen, M S

    2013-10-01

    This study is undertaken to determine the activity concentration of (226)Ra, (232)Th and (40)K in samples of commonly used building materials in Jordan. Samples of seven different materials were collected from construction sites and local agencies supplying raw construction materials and analyzed using a HPGe gamma-ray spectrometer, taking into account self-attenuation in bulk samples. The average specific activity concentrations of (226)Ra, (232)Th, and (40)K ranged from 2.84 to 41.52, 0.78 to 58.42. and 3.74 to 897 Bq/kg, respectively. All the samples had radium equivalent activities well below the limit of 370 Bq/kg set by the Organization for Economic Cooperation and Development (OECD, 1979). External and internal hazard indices, absorbed dose and annual effective dose rate associated with the radionuclides of interest were calculated and compared with the international legislation and guidance. In general, most of the activities did not exceed the recommended international limits, except for granite and ceramic samples which are usually used as secondary building materials in Jordan. PMID:23831927

  15. Quantitative measurement of natural radioactivity in some roofing tile materials used in upper Egypt.

    PubMed

    Uosif, M A M

    2013-09-01

    The quantitative measurement of radionuclides ((226)Ra, (232)Th and (40)K) in some roofing tile materials (granite, alabaster, marble, traditional and advanced ceramic) used in Upper Egypt is presented in this paper. Measurements were done by using gamma spectrometry (NaI (Tl) 3" × 3"). The values of concentration of natural radionuclides were in the following ranges: 12-78.9 Bq kg(-1) for (226)Ra, 8.4-113.1 Bq kg(-1) for (232)Th and 94.9-509 Bq kg(-1)for (40)K. The activity concentration index (I), the specific dose rates indoors ( ) and the annual effective dose (DE) due to gamma radiation were calculated for each investigated sample. The lowest value of I is 0.19 for alabaster, while the highest one is 0.88 for traditional and advanced ceramic. The ranges of DE are between 0.03 and 0.13 mSv, it is below the maximal permitted values, so that the examined materials could be used as roofing tiles in the construction of new buildings. PMID:23516266

  16. Spatial distribution of gamma radiation levels in surface soils from Jaduguda uranium mineralization zone, Jharkhand, India, using γ-ray spectrometry, and determination of outdoor dose to the population

    PubMed Central

    Maharana, Mandakini; Krishnan, Narayani; Sengupta, D.

    2010-01-01

    The concentrations of natural radionuclides in surface soil samples around selected villages of Jaduguda were investigated and compared with the radioactivity level in the region. Concentrations of 238U, 232Th, and 40K were determined by a gamma ray spectrometer using the HPGe detector with 50% relative efficiency, and the radiation dose to the local population was estimated. The average estimated activity concentrations of 238U, 232Th, and 40K in the surface soil were 53.8, 44.2 and 464.2 Bq kg−1 respectively. The average absorbed dose rate in the study area was estimated to be 72.5 nGy h-1, where as the annual effective dose to the population was 0.09 mSv y-1. A correlation analysis was made between measured dose rate and individual radionuclides, in order to delineate the contribution of the respective nuclides towards dose rate. The radio-elemental concentrations of uranium, thorium and potassium estimated for the soils, in the study area, indicated the enrichment of uranium series nuclide. The results of the present study were subsequently compared with international and national recommended values. PMID:21170189

  17. Assessment of radioactivity and radon exhalation rate in Egyptian cement.

    PubMed

    El-Bahi, S M

    2004-05-01

    The cement industry is considered as one of the basic industries that plays an important role in the national economy of developing countries. Activity concentration of 238U, 232Th, and 40K in local cement types from different Egyptian factories has been measured using a shielded HPGe detector. The average values obtained for 238U, 232Th, and 40K activity concentrations in different types of cement are lower than the corresponding global values reported in UNSCEAR publications. On the basis of the hazard index and the radium equivalent concentration, it can be shown that the natural radioactivity of cement samples is not greater than the values permitted in the established standards in other countries. A solid-state nuclear track detector SSNTD (Cr-39) was used to measure the radon concentration as well as exhalation rate for these samples. The effective radium content and the exhalation rate are found to vary from 12.75 to 38.52 Bq kg(-1) and 61.19 to 181.39 Bq m(-2) d(-1), respectively.

  18. An assessment of the external radiological impact in granites and pegmatite in central Eastern Desert in Egypt with elevated natural radioactivity.

    PubMed

    Uosif, M A M; Abdel-Salam, L M

    2011-11-01

    The contents of natural radionuclides ((226)Ra, (232)Th and (40)K) were measured in investigated samples (granite Gabal Ras Barud, Eastern Desert in Egypt) by using gamma spectrometry (NaI (Tl) 3″×3″). The activities of (226)Ra, (232)Th series and (40)K are between (3.8±0.5 and 172.8±1135.1±56.8 8.6), (2.3±0.3 and 103.8±5.2) and (53.1±2.7 and 1135.1±56.8) Bq kg(-1), respectively. With average total annual dose being only 67.2 μSv y(-1), this value is about 6.72 % of the 1.0 mSv y(-1) recommended by the International Commission on Radiological Protection (ICRP-60, 1990) as the maximum annual dose to members of the public. Geochemical studies revealed that Gabal Ras Barud is formed from a highly fractionated biotite granite, with SiO(2) >75 % and generally enriched in alkali with K/Na >8 %.

  19. Radiation dose to Malaysian infants from natural radionuclides via consumption of powdered milk

    SciTech Connect

    Uwatse, Onosohwo Bemigho; Olatunji, Michael Adekunle; Khandaker, Mayeen Uddin; Amin, Yusoff Mohd.

    2015-04-24

    Milk is the basic food stuff for the infants because they generally consume more milk on a daily basis as its minerals and proteins are essential for their growth and development, therefore, it is very important to assess the natural radioactivity levels and the associated dose in the widely consumed powered infant’s milk. As a result, 14 brands of infant’s powdered milk were collected from different supermarkets around Selangor, Malaysia and analysed for {sup 226}Ra, {sup 232}Th and {sup 40}K activities. The obtained mean activity of {sup 226}Ra, {sup 232}Th and {sup 40}K are 3.05±1.84, 2.55±2.48 and 99.1±69.5 Bqkg{sup −1}, respectively. Among the analysed milk samples, the brand from Philippines (Lactogen) showed low level of radioactivity while Singaporean brand (S26 SMA Gold) showed the highest. The estimated mean annual effective doses due to the ingestion of natural radionuclides in the sampled milk are 635 and 111 µSv for infant ≤ 1y and infant 1-2y, respectively. The obtained dose value does not yet pose any significant radiological hazards to the population under investigation comparing with the 1.0 mSvy{sup −1} recommended by ICRP for all ages.

  20. Measurement of natural radioactivity in building materials in Qena city, Upper Egypt.

    PubMed

    Ahmed, Nour Khalifa

    2005-01-01

    Building materials cause direct radiation exposure because of their radium, thorium and potassium content. In this paper, samples of commonly used building materials (bricks, cement, gypsum, ceramics, marble, limestone and granite) in Qena city, Upper Egypt have been collected randomly over the city. The samples were tested for their radioactivity contents by using gamma spectroscopic measurements. The results show that the highest mean value of (226)Ra activity is 205+/-83 Bqkg(-1) measured in marble. The corresponding value of (232)Th is 118+/-14 Bqkg(-1) measured in granite. For (40)K this value is (8.7+/-3.9)x10(2) Bqkg(-1) measured in marble. The average concentrations of the three radionuclides in the different building materials are 116+/-54, 64+/-34 and (4.8+/-2.2)x10(2) Bqkg(-1) for (226)Ra, (232)Th and (40)K, respectively. Radium equivalent activities and various hazard indices were also calculated to assess the radiation hazard. The maximum mean of radium equivalent activity Ra(eq) is 436+/-199 Bqkg(-1) calculated in marble. The highest radioactivity level and dose rate in air from these materials were calculated in marble.

  1. Specific activity and hazards of granite samples collected from the Eastern Desert of Egypt.

    PubMed

    Arafa, Wafaa

    2004-01-01

    Fifty granitic rock samples were collected from different plutons in the central part of the Eastern Desert of Egypt and were analyzed for specific concentrations of (238)U, (232)Th and (40)K radionuclei. The measurements were carried out using a high performance and stability Nomad Plus spectroscopy system attached to a 1.7 keV (FWHM) HPGe detector. The spectra were analyzed using the direct gamma counting comparison method as well as the traditional absolute efficiency curve method. The highest average value of (238)U concentration (1184 Bq kg(-1)) was observed at EI Misikat region whereas the highest average values of (40)K and (232)Th concentration (2301.8 and 162.5 Bq kg(-1) respectively), were detected at Gabal Homret Waggat area. The radium equivalent activity (Ra(eq)), the absorbed dose rate (D), the external hazard index (H(ex)) and the annual gonadal dose equivalent were also calculated and compared to the international recommended values. Radon exhalation rate from the rock samples were measured using the activated charcoal canister method. The average value of radon exhalation varies from 0.052 to 0.69 Bq m(-2) h(-1) and depends on the specific concentration of uranium.

  2. Measurement of natural radioactivity in Jordanian building materials and their contribution to the public indoor gamma dose rate.

    PubMed

    Sharaf, J M; Hamideen, M S

    2013-10-01

    This study is undertaken to determine the activity concentration of (226)Ra, (232)Th and (40)K in samples of commonly used building materials in Jordan. Samples of seven different materials were collected from construction sites and local agencies supplying raw construction materials and analyzed using a HPGe gamma-ray spectrometer, taking into account self-attenuation in bulk samples. The average specific activity concentrations of (226)Ra, (232)Th, and (40)K ranged from 2.84 to 41.52, 0.78 to 58.42. and 3.74 to 897 Bq/kg, respectively. All the samples had radium equivalent activities well below the limit of 370 Bq/kg set by the Organization for Economic Cooperation and Development (OECD, 1979). External and internal hazard indices, absorbed dose and annual effective dose rate associated with the radionuclides of interest were calculated and compared with the international legislation and guidance. In general, most of the activities did not exceed the recommended international limits, except for granite and ceramic samples which are usually used as secondary building materials in Jordan.

  3. Assessment of natural radioactivity in commercial granites used in Turkey.

    PubMed

    Onargan, Turgay; Gür, Filiz; Kaya, Erol; Güneri, Sinem

    2012-01-01

    The activity concentrations of (226)Ra, (232)Th and (40)K in twelve different domestic and imported tiling rocks (granites) used as building materials in Turkey were determined by employing high-resolution γ-ray spectrometry. The samples were evaluated to assess the radiation hazard for people by comparing the results with the control values recommended by the European Commission. The measured activity concentrations ranged from 7 to 136 Bq kg(-1), 9 to 138 Bq kg(-1) and 541 to 1277 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. Applying dose criteria recommended by the European Commission([15]), two of the samples showed higher Ra(eq) values than the limit dose of 370 Bq kg(-1), equivalent to a γ-dose of 1.5 mSv y(-1). The calculated gamma-index (I(γ)) values for all the 12 samples were lower than the recommended dose criterion. In some of the samples; however, the H(ex) and H(in) values were more than unity. The absorbed dose rates (D) for all the samples, except for four samples, were located within the range values recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)([3]). Annual effective dose (AED) values, except for one sample, were greater than the world average value of UNSCEAR([3]).

  4. Norm and associated radiation hazards in bricks fabricated in various localities of the North-West Frontier Province (Pakistan).

    PubMed

    Khan, Khalid; Aslam, M; Orfi, S D; Khan, H M

    2002-01-01

    The activity concentrations of natural gamma-emitting radionuclides and associated radiation hazards due to 40K, 226Ra and 232Th have been measured in baked brick samples, collected from six highly populated areas of the North-West Frontier Province (NWFP) of Pakistan. For the detection, analysis and data acquisition, a high purity germanium (HPGe) detector coupled with a high resolution multichannel analyser (MCA) was used. The range of the average values of the activity concentrations due to 40K, 226Ra and 232Th were found to be 680.3 +/- 22.2-784.4 +/- 30.7 Bq kg(-1), 36.9 +/- 3.5-51.9 +/- 3.3 Bq kg(-1) and 52.5 +/- 3.6-67.6 +/- 3.1 Bq kg(-1), respectively. Radium equivalent (Ra(eq)) activities and various hazard indices were also calculated to assess the radiation hazards. All the brick samples showed Ra, activities within the limit (370 Bq kg(-1)) set by the Organization for Economic Cooperation and Development (OECD) countries. The results of different criterion formulae also complemented each other in this study. The derived data have been compared with the reported values for other countries of the world.

  5. Natural radioactivity hazards of building bricks fabricated from saline soil of two districts of Pakistan.

    PubMed

    Tufail, M; Nasim-Akhtar; Sabiha-Javied; Hamid, Tehsin

    2007-12-01

    Primordial radionuclides in building materials are one of the sources of radiation hazard in dwellings made of those materials. Activity concentrations of primordial radionuclides 40K, 226Ra and 232Th have been measured in house building bricks fabricated from saline soil. Forty samples of the bricks were collected from the brick fabrication sites and brick baking kilns in and around the saline soil areas of the districts of Lahore and Faisalabad in the Punjab province of Pakistan. The technique of gamma-ray spectroscopy using an HPGe detector with a PC-based multi-channel analyser was applied for determination of activity concentrations in the brick samples. The activity mass concentrations of 40K, 226Ra and 232Th measured in the brick samples were respectively 567.7 +/- 38.3 (493-631), 28.4 +/- 3.8 (23-35), and 56.0 +/- 4.6 (46-65) Bq kg(-1). The radiological hazards of the bricks were calculated using various models given in the literature. The radium equivalent activity was less than the accepted standard criterion value of 370 Bq kg(-1) and the values of other hazard indices were also below their limit values. The radiological hazard parameters of the bricks under investigation have been compared with those from other locations of Pakistan and also from some other countries in Asia.

  6. Spatial distribution of gamma radioactivity levels and radiological hazard indices in the East Coastal sediments of Tamilnadu, India with statistical approach

    NASA Astrophysics Data System (ADS)

    Ravisankar, R.; Sivakumar, S.; Chandrasekaran, A.; Prince Prakash Jebakumar, J.; Vijayalakshmi, I.; Vijayagopal, P.; Venkatraman, B.

    2014-10-01

    Natural and artificial radionuclide pollutants of the marine environment have been recognized as a serious environmental concern. The natural radioactivity levels in beach sediment samples collected from Thazhankuda (Cuddalore) to Kodiyakkarai along East Coast of Tamilnadu have been determined. Sediment sample were collected by a Peterson grab sampler from 10 m water depths parallel to the shore line. The grab sampler collects 10 cm thick bottom sediment layer from the seabed along the 20 stations. The radioactivities of 20 samples have been measured with a NaI(Tl) detector. The average specific activities for 238U, 232Th, and 40K were found to be 3.67, 37.23 and 387.17 Bq kg-1 respectively. The results have been compared with other radioactivity measurements in different countries. It shows that the average activity of 238U and 40K is lower whereas 232Th is slightly greater than the compared worldwide average value. The radiation hazard due to the total natural radioactivity in the study area was estimated by different approaches such as the radium equivalent activity (Raeq), absorbed dose rate (DR), hazard indices, the annual gonadal dose equivalent (AGDE) and annual effective dose equivalent (AEDE) are compared with the international recommended values. Multivariate Statistical analyses (Pearson Correlation, Cluster and Factor analysis) were carried out between the parameters obtained from the radioactivity to know the existing relations and to study the spatial distribution of radionuclide.

  7. Analysis of natural radionuclides in soil samples of Purola area of Garhwal Himalaya, India.

    PubMed

    Yadav, Manjulata; Rawat, Mukesh; Dangwal, Anoop; Prasad, Mukesh; Gusain, G S; Ramola, R C

    2015-11-01

    Naturally occurring radioactive materials are widely spread in the earth's environment, being distributed in soil, rocks, water, air, plants and even within the human body. All of these sources have contributed to an increase in the levels of environmental radioactivity and population radiation doses. This paper presents the activity level due to the presence of (226)Ra, (232)Th and (40)K in soil samples of Purola area in Garhwal Himalaya region. The measured activity of (226)Ra, (232)Th and (40)K in collected soil samples of Purola was found to vary from 13±10 to 55±10 Bq kg(-1) with an average of 31±2 Bq kg(-1), 13±10 to 101±13 Bq kg(-1) with an average 30±3 Bq kg(-1) and 150±81 to 1310±154 Bq kg(-1) with an average 583±30 Bq kg(-1), respectively. The radium equivalent activity in collected soil samples was found to vary from 47 to 221 Bq kg(-1) with an average of 115 Bq kg(-1). The total absorbed gamma dose rate in this area was found to vary from 22 to 93 nGy h(-1) with an average of 55 nGy h(-1). The distribution of these radionuclides in the soil of study area is discussed in details.

  8. Radionuclides in the soil around the largest coal-fired power plant in Serbia: radiological hazard, relationship with soil characteristics and spatial distribution.

    PubMed

    Ćujić, Mirjana; Dragović, Snežana; Đorđević, Milan; Dragović, Ranko; Gajić, Boško; Miljanić, Šćepan

    2015-07-01

    Primordial radionuclides, (238)U, (232)Th and (40)K were determined in soil samples collected at two depths (0-10 and 10-20 cm) in the vicinity of the largest coal-fired power plant in Serbia, and their spatial distribution was analysed using ordinary kriging. Mean values of activity concentrations for these depths were 50.7 Bq kg(-1) for (238)U, 48.7 Bq kg(-1) for (232)Th and 560 Bq kg(-1) for (40)K. Based on the measured activity concentrations, the radiological hazard due to naturally occurring radionuclides in soil was assessed. The value of the mean total absorbed dose rate was 76.3 nGy h(-1), which is higher than the world average. The annual effective dose due to these radionuclides ranged from 51.4 to 114.2 μSv. Applying cluster analysis, correlations between radionuclides and soil properties were determined. The distribution pattern of natural radionuclides in the environment surrounding the coal-fired power plant and their enrichment in soil at some sampling sites were in accordance with dispersion models of fly ash emissions. From the results obtained, it can be concluded that operation of the coal-fired power plant has no significant negative impact on the surrounding environment with regard to the content of natural radionuclides.

  9. Measurement of soil radioactivity levels and radiation hazard assessment in southern Rechna interfluvial region, Pakistan.

    PubMed

    Jabbar, Abdul; Arshed, Waheed; Bhatti, Arshad Saleem; Ahmad, Syed Salman; Akhter, Perveen; Rehman, Saeed-Ur; Anjum, Muhammad Iftikhar

    2010-10-01

    Rechna interfluvial region is one of the main regions of Punjab, Pakistan. It is the area which is lying between River Ravi and River Chenab, alluvial-filled. Radioactivity levels in soil samples, collected from southern Rechna interfluvial region, Pakistan, have been estimated by using gamma-ray spectrometric technique. (226)Ra, (232)Th, the primordial radionuclide (40)K, and the artificial radionuclide (137)Cs have been measured in the soil of the study area. The mean radioactivity levels of (226)Ra, (232)Th, (40)K, and (137)Cs were found to be 50.6 +/- 1.7, 62.3 +/- 3.2, 662.2 +/- 32.1, and 3.1 +/- 0.3 Bq kg(-1), respectively. The mean radium equivalent activity (Ra(eq)), outdoor radiation hazard index (H(out)), indoor radiation hazard index (H(in)), and terrestrial absorbed dose rate for the area under study were determined as 190.8 +/- 8.7 Bq kg(-1), 0.52, 0.65, and 69.8 nGy h(-1), respectively. The annual effective dose to the general public was found to be 0.43 mSv. This value lies well below the limit of 1 mSv for general public as recommended by the International Commission on Radiological Protection. The measured values are comparable with other global radioactivity measurements and are found to be safe for the public and the environment.

  10. Terrestrial radioactivity of the Jabal Eghei area in southern Libya and assessment of the associated environmental risks.

    PubMed

    Tereesh, Mehdi Bashir; Radenkovic, Mirjana B; Kovacevic, Jovan; Miljanic, Scepan S

    2013-01-01

    Activity concentrations of main terrestrial radioisotopes (226)Ra, (232)Th and (40)K were measured in geological samples collected in Libya's Jabal Eghei area, in order to contribute to the establishment of a baseline map of the environmental radioactivity levels and to estimate the associated environmental risk to the population. Activity concentrations ranged from 22 to 5256 Bq kg(-1) for (226)Ra, from 11 to 221 Bq kg(-1) for (232)Th and from 132.0 to 2304 Bq kg(-1) for (40)K. Using these results, representative risk factors were calculated: the total absorbed gamma dose rate in air (ranged from 25.5 to 2434.3 nGy h(-1) with a mean value of 251.8 nGy h(-1)), the radium equivalent activity (55-5281 Bq kg(-1), with the mean value of 537 Bq kg(-1)), external hazard index (0.149-14.24, with a mean value of 1.451) and annual outdoor effective dose (31.3-2985.4 μSv, with a mean value of 308.9 μSv). Accordingly, the radiation risk is above the world average, mainly as the consequence of discovered uranium anomalies.

  11. Estimation of radioactivity level and associated radiological hazards of limestone and gypsum used as raw building materials in Rawalpindi/Islamabad region of Pakistan.

    PubMed

    Gul, Rahmat; Ali, Safdar; Hussain, Manzur

    2014-01-01

    This study was undertaken to asses the radioactivity level of limestone and gypsum and its associated radiological hazard due to the presence of naturally occurring radioactive materials. Representative samples of limestone and gypsum were collected from cement factories located in the Rawalpindi/Islamabad region of Pakistan and were analysed by using an N-type high-purity germanium detector of 80 % relative efficiency. The average activity concentration of (40)K, (226)Ra and (232)Th were 60.22±3.47, 29.25±5.23 and 4.07±3.31 Bq kg(-1), respectively, in limestone and 70.86±4.1, 5.01±2.10 and 4.49±3.1 Bq kg(-1), respectively, in gypsum. The radiological hazard parameters radium equivalent activities, absorbed dose rate in air, external hazard index, internal hazard index, annual effective dose equivalent, gamma index and alpha index were computed. The results of the average activity concentrations of (40)K, (226)Ra and (232)Th and radiological hazard parameters were within the range of the reported average worldwide/United Nations Scientific Committee on the Effect of Atomic Radiation values. It is concluded that limestone and gypsum used in the Rawalpindi/Islamabad region does not pose any excessive radiological health hazard as a building raw materials and in industrial uses.

  12. Assessment of radiological hazard of NORM in Margalla Hills limestone, Pakistan.

    PubMed

    Ali, Muhammad; Qureshi, Aziz Ahmed; Waheed, Abdul; Baloch, Muzahir Ali; Qayyum, Hamza; Tufail, Muhammad; Khan, Hameed Ahmed

    2012-08-01

    Studies on naturally occurring radioactive material (NORM) in the limestone from the Margalla Hills have been carried out by measuring gamma activity and to access its radiological implications if any. For data acquisition, a High-Purity Germanium detector was employed. The activity concentrations of (226)Ra, (232)Th, and (40)K were found to be 14.32 ± 0.24, 2.05 ± 0.04, and 13.80 ± 0.20 Bq kg(-1), respectively. These values are relatively lower as compared to that in the limestone of other countries and much lower than the values reported for the natural building stones. The average specific activities due to (226)Ra were found to be higher when compared with (40)K and (232)Th. Indices of radium equivalent activity (Ra(eq)), internal hazard (H(in)), indoor absorbed gamma dose rate (D(R,)), and corresponding annual effective dose (E(eff)) were also determined for the limestone-made rooms. All of these indices were found to be in the lower ranges. The Margalla Hills limestone does not pose any excessive radiological health hazard as a building material and in industrial uses for a common man.

  13. Radionuclide content of NORM by-products originating from the coal-fired power plant in Oroszlány (Hungary).

    PubMed

    Kardos, R; Sas, Z; Hegedűs, M; Shahrokhi, A; Somlai, J; Kovács, T

    2015-11-01

    At the Thermal Power Plant in Oroszlány (Hungary), a huge amount of by-products have been produced since 1961. In this survey, coal and other by-products were examined (fly ash, bottom ash, fluidised bed bottom ash, gypsum and slurry-type ash). The natural isotopes were determined using an HPGe detector. It was found that the radionuclide content of coal was significantly lower ((226)Ra = 45.3±6.3, (232)Th = 26.3±5.7 and (40)K = 210±21 Bq kg(-1)) than that in the case of ashes other than the fluidised type. The average values of the bottom ash-deposited in the largest quantities-were three times higher than those for coal ((226)Ra = 144±18, (232)Th = 84.3±14 and (40)K = 260±25 Bq kg(-1)). In the case of fractionised bottom ash, the radionuclide content of <0.1 mm was 45 % higher than that of >1.6 mm and the massic radon exhalation of <0.1 mm was approximately four times higher than that above this range.

  14. Natural and anthropogenic radioactivity levels and the associated radiation hazard in the soil of Oodalia Tea Estate in the hilly region of Fatickchari in Chittagong, Bangladesh

    PubMed Central

    Absar, Nurul; Rahman, M. Mashiur; Kamal, Masud; Siddique, Naziba; Chowdhury, Mantazul Islam

    2014-01-01

    Radioactivity in the soil of a tea garden in the Fatickchari area in Chittagong, Bangladesh, was measured using a high-resolution HPGe detector. The soil samples were collected from depths of up to 20 cm beneath the soil surface. The activity concentrations of naturally occurring 238U and 232Th were observed to be in the range of 27 ± 7 to 53 ± 8 Bq kg−1 and 36 ± 11 to 72 ± 11 Bq kg−1, respectively. The activity concentration of 40K ranged from 201 ± 78 to 672 ± 81 Bq kg−1, and the highest activity of fallout 137Cs observed was 10 ± 1 Bq kg−1. The average activity concentration observed for 238U was 39 ± 8 Bq kg−1, for 232Th was 57 ± 11 Bq kg−1, for 40K was 384 ± 79 Bq kg−1 and for 137Cs was 5 ± 0.5 Bq kg−1. The radiological hazard parameters (representative level index, radium equivalent activity, outdoor and indoor dose rates, outdoor and indoor annual effective dose equivalents, and radiation hazard index) were calculated from the radioactivity in the soil. PMID:25078001

  15. An assessment of the external radiological impact in granites and pegmatite in central Eastern Desert in Egypt with elevated natural radioactivity.

    PubMed

    Uosif, M A M; Abdel-Salam, L M

    2011-11-01

    The contents of natural radionuclides ((226)Ra, (232)Th and (40)K) were measured in investigated samples (granite Gabal Ras Barud, Eastern Desert in Egypt) by using gamma spectrometry (NaI (Tl) 3″×3″). The activities of (226)Ra, (232)Th series and (40)K are between (3.8±0.5 and 172.8±1135.1±56.8 8.6), (2.3±0.3 and 103.8±5.2) and (53.1±2.7 and 1135.1±56.8) Bq kg(-1), respectively. With average total annual dose being only 67.2 μSv y(-1), this value is about 6.72 % of the 1.0 mSv y(-1) recommended by the International Commission on Radiological Protection (ICRP-60, 1990) as the maximum annual dose to members of the public. Geochemical studies revealed that Gabal Ras Barud is formed from a highly fractionated biotite granite, with SiO(2) >75 % and generally enriched in alkali with K/Na >8 %. PMID:21131664

  16. The natural radioactivity in some Nigerian foodstuffs

    NASA Astrophysics Data System (ADS)

    Olomo, James B.

    1990-12-01

    The average activity concentrations of seven locally produced food commodities that form the total diets of a baby, a teenager or an adult male in Nigeria were measured by means of a well-calibrated high-resolution lithium-drifted germanium (Ge(Li)) spectrometer system. The food commodities were collected at several centers such as a nuclear research center as well as metropolitan and industrial areas. The emission lines identified with reliable regularity belonged to the 238U and 232Th decay series. The other isotope is a non-related naturally occurring radionuclide, 40K. Average total specific-activity values of 7.29 ± 1.08, 6.27 ± 1.01 and 11.23 ± 1.64 Bq/kg for 238U, 232Th and 40K, respectively, were obtained for the seven food commodities studied. The food samples were also checked for fission-product residues ( 137Cs and 90Sr) from atmospheric weapons tests which are slowly being purged from the food chain. Their estimation revealed that they were below the minimum detectable limit determined at a two-standard deviation analytical error.

  17. Natural and anthropogenic radioactivity levels and the associated radiation hazard in the soil of Oodalia Tea Estate in the hilly region of Fatickchari in Chittagong, Bangladesh.

    PubMed

    Absar, Nurul; Rahman, M Mashiur; Kamal, Masud; Siddique, Naziba; Chowdhury, Mantazul Islam

    2014-11-01

    Radioactivity in the soil of a tea garden in the Fatickchari area in Chittagong, Bangladesh, was measured using a high-resolution HPGe detector. The soil samples were collected from depths of up to 20 cm beneath the soil surface. The activity concentrations of naturally occurring (238)U and (232)Th were observed to be in the range of 27 ± 7 to 53 ± 8 Bq kg(-1) and 36 ± 11 to 72 ± 11 Bq kg(-1), respectively. The activity concentration of (40)K ranged from 201 ± 78 to 672 ± 81 Bq kg(-1), and the highest activity of fallout (137)Cs observed was 10 ± 1 Bq kg(-1). The average activity concentration observed for (238)U was 39 ± 8 Bq kg(-1), for (232)Th was 57 ± 11 Bq kg(-1), for (40)K was 384 ± 79 Bq kg(-1) and for (137)Cs was 5 ± 0.5 Bq kg(-1). The radiological hazard parameters (representative level index, radium equivalent activity, outdoor and indoor dose rates, outdoor and indoor annual effective dose equivalents, and radiation hazard index) were calculated from the radioactivity in the soil.

  18. Assessment of natural radioactivity in phosphate ore, phosphogypsum and soil samples around a phosphate fertilizer plant in Nigeria.

    PubMed

    Okeji, Mark C; Agwu, Kenneth K; Idigo, Felicitas U

    2012-11-01

    The radionuclides present in phosphate ore, phosphogypsum and soil samples in the vicinity of a phosphate fertilizer plants in Nigeria were identified and their activity concentration determined to assess the potential radiation impact on the environment due to fertilizer production. The mean activity concentration of (238)U, (232)Th, and (40)K radionuclides in phosphate ore samples were 616 ± 38.6, BDL (Below Detection Level) and 323.7 ± 57.5 Bq kg(-1) respectively. For the phosphogypsum, 334.8 ± 8.8, 4.0 ± 1.4, and 199.9 ± 9.3 Bq kg(-1) respectively and for soil samples range from 20.5 ± 7.3 to 175.7 ± 10.5 Bq kg(-1) for (226)Ra, 15.5 ± 1.5 to 50.4 ± 0.6 Bq kg(-1) for (232)Th and 89.5 ± 8.1 to 316.1 ± 41.3 Bq kg(-1) for (40)K respectively. The mean absorbed dose rate was 71.4 nGy h(-1). The mean annual effective dose was 86 μSv.

  19. Radioactivity of a Rock Profile from Rio do Rasto Formation Measured by High Resolution Gamma Spectrometry

    NASA Astrophysics Data System (ADS)

    Bastos, Rodrigo O.; Appoloni, Carlos R.; Pinese, José P. P.

    2011-08-01

    Natural occurring radionuclides are present in different concentrations in sedimentary rocks. Generally, their distribution correlates reasonably with their geo-physicochemical behavior during sediment deposition and rock consolidation. This fact permits to study some geological characteristics of the rocks by analyzing the radionuclide distribution in the rocks, as it might reflect the origin of the sediments, the depositional environment, and more recent events such as weathering and erosion. In this work, rocks from an exposed profile of the Rio do Rasto Formation were collected and analyzed in laboratory by high resolution gamma spectrometry for 226Ra, 232Th and 40K determination. It was employed a standard gamma ray spectrometry electronic chain, with a 66% relative efficiency HPGe detector. The efficiency calibration, as well as its validation, was accomplished with eight International Atomic Energy Agency certified samples. The outcrop exposes layers of sandstone and siltstone and, secondarily, claystone, with varying colors (gray, red and green). The rocks were collected along this profile, each of them was dried in the open air during 48 hours, grounded, sieved through 4 mm mesh and sealed in cylindrical recipients. The 226Ra, 232Th and 40K activity concentrations are presented, their distribution and the possible relations among activities are analyzed. The general pattern of radionuclides distribution respects well the hypotheses on geo-physicochemical behavior of radioactive elements.

  20. Analysis of internal exposure associated with consumption of crops and groundwater from the high background radiation area of Mrima Hill, Kenya.

    PubMed

    Chege, M W; Hashim, N O; Merenga, A S; Tschiersch, J

    2015-11-01

    Specific concentrations of (226)Ra, (232)Th and (40)K were measured in cassava tubers, cassava leaves and groundwater obtained from the high background radiation area of Mrima hill and used in the evaluation of the ingested dose. Cassava tubers, cassava leaves and groundwater registered average (226)Ra concentrations of 60 ± 5, 141 ± 11 and 4.3 ± 0.3 Bq kg(-1), respectively. (232)Th was not detected in cassava leaves although it was present in cassava tubers as well as in groundwater in average concentrations of 35.3±61.5 and 2.0±0.1 Bq kg(-1), respectively. (40)K was present in all samples in average concentrations of 842±539 Bq kg(-1) in cassava tubers, 1708 ± 552 Bq kg(-1) in cassava leaves and 91.4 Bq kg(-1) in groundwater. The total annual effective dose due to ingestion was found to be 7.9 mSv y(-1) of which 2.4 mSv y(-1) was due to cassava tubers, 3.8 mSv y(-1) due to cassava leaves and 1.7 mSv y(-1) due to water.