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Sample records for u-series radioactive disequilibria

  1. Assimilation of the plutonic roots of the Andean arc controls variations in U-series disequilibria at Volcan Llaima, Chile

    NASA Astrophysics Data System (ADS)

    Reubi, O.; Bourdon, B.; Dungan, M. A.; Koornneef, J. M.; Sellés, D.; Langmuir, C. H.; Aciego, S.

    2011-02-01

    U-series disequilibria provide important constraints on the processes and time scales of melt production, differentiation, and transport in subduction settings. Such constraints, which are essential for understanding the chemical evolution of the continental crust, are conventionally based on the assumption that the U-series disequilibria measured in mafic lavas are produced during mantle metasomatism and melting, and that intracrustal differentiation and assimilation have limited impacts. Here we show that mantle-derived U-series disequilibria in mafic lavas erupted at Volcán Llaima, Chile are significantly diminished by assimilation of plutonic rocks forming Llaima's subvolcanic basement. This contamination process is extremely subtle in terms of "classical" indicators of crustal assimilation like Sr, Nd or Pb isotopes because it is a manifestation of assimilative recycling of the plutonic roots of the arc. This process results in variations in U-series disequilibria and incompatible trace element ratios that are significant compared to regional and global variability in arc magmas. Furthermore, it yields linear correlations between U-series excesses and incompatible trace element ratios that are generally interpreted as slab-fluid indicators and chronometers, or tracers of sediment recycling in subduction zone. Cannibalization of ancestral magmas by ascending melts warrants careful evaluation when considering the components and chemical fluxes in subduction zones. Linear arrays defined by activity ratios of U-series nuclides with different half-lives may be the most reliable indicators of assimilative recycling of ancestral intrusive magmas.

  2. CHARACTERIZATION OF CONTAMINANT TRANSPORT USING NATURALLY-OCCURRING U-SERIES DISEQUILIBRIA

    EPA Science Inventory

    The interactions of mixed wastes containing radionuclides with solid rock surface and the mobility of the radionuclides in aquifer systems depend not only on the chemistry of the nuclides and the physico-chemical effects of radioactive decay, but also on the site-specific hydroge...

  3. 235U fission tracks and 238U-series disequilibria as a means to study recent mobilization of uranium in Archaean pyritic conglomerates

    NASA Astrophysics Data System (ADS)

    Thiel, K.; Vorwerk, R.; Saager, R.; Stupp, H. D.

    1983-11-01

    Uranium transport in Archaean sediments was investigated by means of two carefully selected suites of variably weathered sediment samples from different localities of the Pongola Supergroup, Kaapvaal Craton, South Africa. U remobilization on a micron- to meter-scale was analyzed using U fission-track micromapping and α-spectrometry bulk measurements. These studies were supported by ore microscopy, neutron activation analysis and γ-spectrometry. By combining particle track technique and α-spectrometry detailed information is obtained on the U transport history of weathered surface samples. A simple model of U redistribution processes in geologic systems based on 238U-series disequilibria is developed and applied to the samples investigated. Some implications for γ-radiometric field methods are discussed.

  4. Characterization of Contaminant Transport using Naturally-Occurring U-Series Disequilibria - Final Report - 05/01/1997 - 04/30/2001

    SciTech Connect

    Murrell, Michael T.; Ku, Teh-Lung

    2001-04-30

    The interactions of mixed wastes containing radionuclides with solid rock surface and the mobility of the radionuclides in aquifer systems depend not only on the chemistry of the nuclides and the physico-chemical effects of radioactive decay, but also on the site-specific hydrogeology. Thus, to characterize contaminant transport, it is best to cross-check figures derived from any small-scale laboratory experiments over limited times with that obtained from field-oriented, natural analog studies. We propose such a study using the naturally-occurring U and Th decay-series disequilibria. The work of ours and other researchers have shown that the parent/daughter disequilibrium patterns existing in groundwater systems can be modeled in terms of local nuclide mass balance to arrive at such information as the rock-water contact time (fluid flow) and rates of contaminant transport, taking into account the retardation effect due to nuclide/rock interaction contaminants at INEL by grouping them into three categories, represented by isotopes of (1) Th and Pa, (2) U and (3) Ra. Mass spectrometric measurements of these elements will be emphasized in order to minimize sample size requirements and to maximize precision. Results will form the data base for a model code for computing: (1) Fluid residence time (transport rates) in the basalt aquifers at various locations, (2) The in-situ adsorption and desorption rate constants, as well as the retardation factors, of various radionuclide wastes, and (3) Rock dissolution rate and its relation to preferential flow and contamination transport in the fractured rock.

  5. Radioactive disequilibria in mineralised fracture samples from two uranium occurrences in northern Sweden

    USGS Publications Warehouse

    Smellie, John A.T.; Rosholt, J.N.

    1984-01-01

    Mineralised fractures from two uranium occurrences in northern Sweden were examined mineralogically and isotopically to establish the presence or absence of radioactive equilibrium that may indicate recent rock-water interaction processes based on the natural mobility of uranium (i.e.; during the last 0.5 Ma). The results show evidence of radioactive disequilibrium in six of the nine samples investigated. Disequilibria are attributable to solution to solid 234U recoil gain (weakly mineralised zones adjacent to the main mineralisation) and solid to solution 234U recoil loss (moderate to highly mineralised zones). The absence of significant 238U loss in the samples emphasises the reducing conditions at the sampled depths. ?? 1984.

  6. Internal tides and sediment dynamics in the deep seaEvidence from radioactive 234Th/ 238U disequilibria

    NASA Astrophysics Data System (ADS)

    Turnewitsch, Robert; Reyss, Jean-Louis; Nycander, Jonas; Waniek, Joanna J.; Lampitt, Richard S.

    2008-12-01

    Residual flow, barotropic tides and internal (baroclinic) tides interact in a number of ways with kilometer-scale seafloor topography such as abyssal hills and seamounts. Because of their likely impact on vertical mixing such interactions are potentially important for ocean circulation and the mechanisms and the geometry of these interactions are a matter of ongoing studies. In addition, very little is known about how these interactions are reflected in the sedimentary record. This multi-year study investigates if flow/topography interactions are reflected in distributional patterns of the natural short-lived (half-life: 24.1 d) particulate-matter tracer 234Th relative to its conservative (non-particle-reactive) and very long-lived parent nuclide 238U. The sampling sites were downstream of, or surrounded by, fields of short seamounts and, therefore, very likely to be influenced by nearby flow/topography interactions. At the sampling sites between about 200 and 1000 m above the seafloor recurrent 'fossil' disequilibria were detected. 'Fossil' disequilibria are defined by clearly detectable 234Th/ 238U disequilibria (total 234Th radioactivity < 238U radioactivity, indicating a history of intense particulate 234Th scavenging and particulate-matter settling from the sampled parcel of water) and conspicuously low particle-associated 234Th activities. 'Fossil' disequilibria were centered at levels in the water column that correspond to the average height of the short seamounts near the sampling sites. This suggests the 'fossil' disequilibria are formed on the seamount slopes. Moreover, the magnitude of the 'fossil' disequilibria suggests that the slopes of the short seamounts in the study region are characterized by particularly vigorous fluid dynamics. Since 'fossil' disequilibria already occurred at O(1-10 km) away from the seamount slopes it is likely that these vigorous fluid dynamics rapidly decay away from the slopes on scales of O(1-10 km). These conclusions are supported by the horizontal distribution and magnitude of the modeled total (barotropic+baroclinic) tidal current velocities of the predominating tidal M 2 constituent: on (near-)critical seamount slopes baroclinic tides lead to localized [ O(1 km)] increases of the overall tidal current velocity by a factor of 2, thereby pushing the total current velocity well above the threshold for sediment erosion. The results of this and a previous study [Turnewitsch, R., Reyss, J.-L., Chapman, D.C., Thomson, J., Lampitt, R.S., 2004. Evidence for a sedimentary fingerprint of an asymmetric flow field surrounding a short seamount. Earth and Planetary Science Letters 222(3-4), 1023-1036] show that kilometer-scale flow/topography interactions leave a marine geochemical imprint. This imprint may help develop new sediment proxies for the reconstruction of past changes of fluid dynamics in the deep sea, including residual and tidal flow. Sedimentary records controlled by kilometer-scale seafloor elevations are promising systems for the reconstruction of paleo-changes of deep-ocean fluid dynamics. For the sediment-based reconstruction of paleo-parameters other than physical oceanographic ones it may be advisable to avoid kilometer-scale topography altogether.

  7. U-series Disequilibria in Continental Arcs: NE Japan Case

    NASA Astrophysics Data System (ADS)

    Tepley, F. J.; Gill, J. B.; Williams, R. W.

    2005-12-01

    Basalts and andesites from continental arcs typically are close to equilibrium between (238U) and (230Th), and have subdued excesses of 226Ra compared to oceanic arcs (Turner et al., 2003). There is ambiguity whether these and other geochemical features derive from subducted sediment, subcontinental lithosphere, or the crust. We report new 238U-234U-230Th-226Ra data for 20 historical to Holocene samples from Asama in the south of NE Japan to Tarumai in the north. Most straddle the equiline with <5% excess U or Th, yet have 10-60% excess 226Ra. The only significant excess U occurs at Usu and Iwaki in the north where it correlates with higher (230Th)/(232Th) as in other arcs (e.g., Mariana). Otherwise (230Th)/(232Th) ratios are 0.75-1.05 which is less than in the surrounding Izu and Kurile oceanic arcs. Most ratios <0.95 are associated with trace element evidence of crustal contamination that drags samples down the equiline. The exception is Iwate where Th/U ratios are ~4.0 even in depleted basalts. Excess 226Ra is greater in basalts than andesites. The excess 226Ra, plus elevated 10Be and Th, is attributed to ubiquitous slab inputs that are overprinted by even higher Th contents from a crustal source with Th/U >4.

  8. Use of U-series nuclides to constrain sediments transfer-times in the alluvial plains: example of the Ganges and Bramaputra river system.

    NASA Astrophysics Data System (ADS)

    Chabaux, Franois; Granet, Mathieu; Blaes, Estelle; Stille, Peter; France-Lanord, Christian; Dosseto, Antony

    2010-05-01

    U-series nuclides have the potential to bring important information on the transfer time of sediments in the alluvial plains. This is a consequence of the dual property of these nuclides 1) to be fractionated during physical denudation and chemical weathering processes and 2) to have radioactive decay periods of the same order of magnitude as the time-scales of these processes (e.g. Chabaux et al., 2003b, 2008). We have illustrated such a potential with the analysis of U-series disequilibria in sediments collected in the Ganges and Bramaputra river basin. The approach relies on the analysis of U-series in river sediments collected along the streams. Indeed, as illustrated in Granet et al. (2007), in large alluvial plains where sediments are only transferred and not affected by additional inputs of new weathering products from fresh rocks, the intensity of 238U-234U-230Th disequilibria in river sediments will only depend on two parameters: (a) the duration of the transfer including the time spent in soils and in the river, and (b) the nature and the intensity of U-Th fractionations occurring in sediments during their transfer into alluvial plains. Recovering time information from the variation of U-Th disequilibria in such sediments requires therefore the use of realistic models accounting for the U-Th fractionation of sediments during their transfers into the plain. From the data, it is proposed for the Ganges and Bramaputra river sediments, that the main U-Th fractionation process is connected with the sediment weathering during their transit and storage in the plain. In this case the U-Th variation in sediments along the two main rivers lead to quite long sediment transfer time in the alluvial plains, of 100-150 ky for Bramaputra plain and of 400 or 500 ky for the Ganges river. Chabaux F., Riotte J., Dequincey O. (2003) U-Th-Ra fractionation during weathering and river transport, Rev Mineral. Geochem. 52, 533-576. Chabaux, F., Bourdon, B., Riotte, J., 2008. U-series Geochemistry in weathering profiles, river waters and lakes. In : S. Krishnaswami and J.K. Cochran (Eds.), U/Th Series Radionuclides in Aquatic Systems, Elsevier, Radioactivity in the Environment, 13, 49-104 M. Granet, F. Chabaux, C. France-Lanord, P. Stille, E. Pelt (2007). Time-scales of sedimentary transfer and weathering processes from U-series nuclides: Clues from the Himalayan rivers, Earth and Planetary Science Letters, 261, 389-406.

  9. Characterization of U-series disequilibria at the Pena Blanca natural analogue site, Chihuahua, Mexico

    SciTech Connect

    Wong, V.; Goodell, P.C.; Anthony, E.Y.

    1999-07-01

    The purpose of this study was to evaluate radionuclide migration from a uranium-mineralized breccia pipe. The site provides an excellent opportunity to evaluate radionuclide mobility in a geochemical environment similar to that around the proposed high-level waste repository at Yucca Mountain, Nevada. Samples represent fracture-infillings from both within and outside the breccia pipe. Mineral assemblages within the fractures include (1) pure kaolinite, (2) a mixture of iron-oxyhydroxides (goethite and hematite) with associated alunite and jarosite, which the authors refer to as the Fe-mineral assemblage, and (3) carbonates. Uranophane, weeksite, soddyite, and boltwoodite are associated with samples from within the breccia zone. The authors obtain radionuclide activities from gamma-ray rather than alpha spectroscopy, and the methodology for these measurements is presented in detail. Plots of {sup 230}Th/{sup 238}U vs. {sup 226}Ra/{sup 230}Th show three distinct mobility trends. (1) The majority of the Fe-mineral samples from within the breccia pipe yield values between 1.0 and 1.1 for both ratios, (2) Fe-mineral samples from outside the ore zone and a kaolinite from within the ore zone have {sup 230}Th/{sup 238}U of 0.58 to 0.83 and {sup 226}Ra/{sup 230}Th of 1.09 to 1.42, and (3) some Fe-mineral samples from within the breccia pipe have values of 1.2 and 0.9 respectively. These data, combined with those from other studies at Pena Blanca suggest that U and Ra are sometimes mobile in the near-surface environment and that multiple episodes of enrichment and leaching are required to explain the trends.

  10. Investigation of 238U- 230Th- 226Ra and 232Th- 228Ra- 228Th radioactive disequilibria in volcanic rocks from Trindade and Martin Vaz Islands (Brazil; Southern Atlantic Ocean)

    NASA Astrophysics Data System (ADS)

    Santos, Rosana N.; Marques, Leila S.

    2007-03-01

    This paper presents the first results of 238U- 230Th- 226Ra and 232Th- 228Ra- 228Th radioactive disequilibria of alkaline volcanic rocks from Trindade and Martin Vaz islands (Southern Atlantic Ocean Brazil). Th and U concentrations reinforce the role of fractional crystallization in the genesis of Trindade volcanics and allow dividing the rocks in three groups: Group I is characterized by phonolites depleted in U in relation to Th, whose genesis can be explained by mineral assemblage fractionation with high uranium partition coefficients (magnetite, apatite and/or titanite); Group II is composed of ultrabasic, basic and intermediate rocks, with relatively high U contents in respect to Th, whose enrichment is probably caused by the presence of small comagmatic xenoliths containing accumulation of those fractionated mineral phases; Group III is composed of remaining rocks, which tend to present despite of some variation homogeneous Th/U ratios (average = 4.6 0.8). Very low degrees (1-2%) of partial melting generated ultrabasic rocks of the last group, which are highly SiO 2 undersaturated, and together with Ascension volcanics have the highest Th/U ratios of all OIB from Southern Atlantic Ocean. Activity ratios of ( 234U/ 238U), ( 230Th/ 238U), ( 226Ra/ 238U), ( 226Ra/ 230Th), ( 228Ra/ 232Th), and ( 228Th/ 232Th) are equal to unity in all phonolites and some basic and ultrabasic rocks belonging to Trindade Complex and Desejado Sequence, agreeing with ages more than 300 ky. Martin Vaz peralkaline phonolite also presents activity ratios indicating radioactive equilibrium, except for ( 226Ra/ 238U), which is significantly smaller than unity as the result of 226Ra steady mobilization. Rocks from the three youngest volcanic episodes of Trindade (Morro Vermelho Formation, Valado Formation, and Vulco do Paredo) present ( 230Th/ 238U) and ( 226Ra/ 238U) ratios distinct from unity, showing also a significant 230Th enrichment, and all pairs of activity ratios indicate system closure between 8 and 300 ky ago. ( 230Th/ 232Th) and ( 238U/ 232Th) data of Morro Vermelho rocks allowed determining an age of 111 20 ky. Radioactive disequilibrium between 238U and 226Ra of Valado Formation rocks, associated with literature information constrain the system was closed between 8 and 11 ky. For ultrabasic rocks, calculated 230Th 0 excesses, along with Th/U ratios do not show significant correlations with K 2O contents, therefore if phlogopite remained as a residual phase during K-poor magma generation, this mineral did not fractionate Th because of its very small partition coefficient. The relatively low ( 230Th/ 232Th) 0 in comparison with measured 87Sr/ 86Sr, plotting slightly below the mantle array, may be explained either by a relatively long time (maximum of about 110 ky for Morro Vermelho Formation) of magma transfer towards surface or, more probably, by melting of heterogeneous mantle due to a metasomatic event occurred between 111 and 300 ky, followed by a very short magma transfer time (hundreds of years).

  11. The U-series comminution approach: where to from here

    NASA Astrophysics Data System (ADS)

    Handley, Heather; Turner, Simon; Afonso, Juan; Turner, Michael; Hesse, Paul

    2015-04-01

    Quantifying the rates of landscape evolution in response to climate change is inhibited by the difficulty of dating the formation of continental detrital sediments. The 'comminution age' dating model of DePaolo et al. (2006) hypothesises that the measured disequilibria between U-series nuclides (234U and 238U) in fine-grained continental (detrital) sediments can be used to calculate the time elapsed since mechanical weathering of a grain to the threshold size ( 50 µm). The comminution age includes the time that a particle has been mobilised in transport, held in temporary storage (e.g., soils and floodplains) and the time elapsed since final deposition to present day. Therefore, if the deposition age of sediment can be constrained independently, for example via optically stimulated luminescence (OSL) dating, the residence time of sediment (e.g., a palaeochannel deposit) can be determined. Despite the significant potential of this approach, there is still much work to be done before meaningful absolute comminution ages can be obtained. The calculated recoil loss factor and comminution age are highly dependent on the method of recoil loss factor determination used and the inherent assumptions. We present new and recently published uranium isotope data for aeolian sediment deposits, leached and unleached palaeochannel sediments and bedrock samples from Australia to exemplify areas of current uncertainty in the comminution age approach. In addition to the information gained from natural samples, Monte Carlo simulations have been conducted for a synthetic sediment sample to determine the individual and combined comminution age uncertainties associated to each input variable. Using a reasonable associated uncertainty for each input factor and including variations in the source rock and measured (234U/238U) ratios, the total combined uncertainty on comminution age in our simulation (for two methods of recoil loss factor estimation: weighted geometric and surface area measurement with an incorporated fractal correction) can amount to ± 220-280 ka. The modelling shows that small changes in assumed input values translate into large effects on absolute comminution age. To improve the accuracy of the technique and provide meaningful absolute comminution ages, much tighter constraints are required on the assumptions for input factors such as the fraction of alpha-recoil lost 234Th and the initial (234U/238U) ratio of the source material. In order to be able to directly compare calculated comminution ages produced by different research groups, the standardisation of pre-treatment procedures, recoil loss factor estimation and assumed input parameter values are required. We suggest a set of input parameter values for such a purpose.

  12. U-Series Dating of Tropical Stalagmites

    NASA Astrophysics Data System (ADS)

    Adkins, J. F.; Carolin, S. A.; Cobb, K.; Subhas, A. V.; Rider, A.; Meckler, N.

    2013-12-01

    Stalagmites are often seen as one of the ideal phases for U-series disequilibrium dating. Typically closed systems with high 234/238 ratios and little initial Th-230, these samples have yielded some of the most precise and accurate ages of the climate system over the last half million years. However, conditions in tropical cave systems can fail on all of these criteria, many times all of them at once. We use our set of over 400 U-series analyses in stalagmites and dozens of others from host rocks and drip waters from the karst region in Northern Borneo to show how problems with low uranium content, very depleted 234/238 ratios, and high ';detrital' thorium can be overcome to yield quality dates. Isochrons are an important tool, and we explore their advantages and weaknesses, but understanding the location and signature of hiatuses is also important. We have developed several geochemical lines of evidence for how to identify these pauses in stalagmite growth. In addition we explore how many of these conditions might come about and how they may be ubiquitous to tropical systems worldwide. The most puzzling observation is low 234/238 ratios. Ranging from near secular equilibrium to values below -600 permil, the missing U-234 requires some specific weathering scenarios to explain the complementary suite of rocks, waters, and stalagmites. Other Me/Ca data helps understand the degree that prior precipitation affects the range U-series data. Some simple numerical models of water moving through karst help us to understand the implications of these extensive data sets.

  13. Time-scales of sedimentary transfer and weathering processes from U-series nuclides: Clues from the Himalayan rivers

    NASA Astrophysics Data System (ADS)

    Granet, M.; Chabaux, F.; Stille, P.; France-Lanord, C.; Pelt, E.

    2007-09-01

    In order to define time-scales of erosion and sedimentary transfer in the Himalaya, 238U- 234U- 230Th disequilibria have been analysed in river bank sediments and in bedloads collected along the Kali Gandaki river, one of the main Nepalese rivers, and in the Ghaghara and Gandak rivers, two major plain tributaries of the Ganges. The Th activity ratios and U/Th ratios in river sediments of the two Ganges tributaries constantly decrease from upstream to downstream. This is related to the maturation of sediments by weathering during their transfer to the plain. The U-series data allow to calculate a transfer time for the sediments in the alluvial Gangetic plain from the chain front to the confluence with the Ganges of about 100 kyr for both rivers. The Kali Gandaki river sediment data highlight a decrease of both the Th isotopic and U/Th ratios which is explained by a mixing between two sources with similar U/Th ratios but having suffered a different U-Th fractionation history. Interpretation of the U-series data in the frame of this scenario gives long time-scales of weathering of several 100's kyr for the Himalayan terranes. The results imply that Himalayan bedrocks are submitted to a long in situ stage of weathering before their erosion and transfer into the rivers. In addition, occurrence of similar U-Sr signatures in dissolved (i.e. < 0.1-0.2 ?m) and sediment phases of the Kali Gandaki river suggests that "dissolved" uranium could be carried by colloids constituted by sedimentary microparticles. This precludes the use of U-series disequilibria in this river to calculate weathering budgets and to assess whether the erosion is working at steady-state or not.

  14. Time scale and conditions of weathering under tropical climate: Study of the Amazon basin with U-series

    NASA Astrophysics Data System (ADS)

    Dosseto, A.; Bourdon, B.; Gaillardet, J.; Allgre, C. J.; Filizola, N.

    2006-01-01

    The Rio Solimes/Amazonas (Amazon River) and its major tributaries have been analyzed for U-series nuclides. 238U- 234U- 230Th- 226Ra disequilibria have been measured in the dissolved (<0.2 ?m) and suspended loads (>0.2 ?m) as well as bed sands. U-series disequilibria are closely related to major and trace element compositions and therefore reflect elemental fractionation during chemical weathering. Moreover, while the dissolved load records present-day weathering, suspended particles integrate the erosion history over much longer time scales (>100 ka). Lowland rivers are characterized by long time scales of chemical erosion (?100 ka) resulting in a high weathering intensity. Moreover, exchange between suspended particles and the dissolved load may explain the U-series signature for these rivers. By combining U-series and Pb isotopes in suspended particles, we show that erosion in the Rio Madeira basin occurred as a multi-step process, whereby the pristine continental crust was eroded several hundreds of Ma ago to produce sediments that have then been integrated in the Cordillera by crustal shortening and are currently eroded. In contrast, recent erosion of a pristine crust is more likely for the Rio Solimes/Amazonas (<10 ka). The suspended particles of the rivers draining the Andes (Solimes/Amazonas, Madeira) suggest time scales of weathering ranging between 4 and 20 ka. This indicates that suspended particles transported by those rivers are not stored for long periods in the Andean foreland basin and the tropical plain. The sediments delivered to the ocean have resided only a few ka in the Amazon basin (6.3 1 ka for the Rio Amazonas at bidos). Nevertheless, a large fraction of the sediments coming out from the Andes are trapped in the foreland basin and may never reach the ocean. Erosion in the Andes is not operating in steady state. U-series systematics shows unambiguously that rivers are exporting a lot more sediments than predicted by steady-state erosion and that is a consequence of soil destruction greater than production. By relating this observation to the short time scales of weathering inferred for the Andes (a few ka), it appears that the erosion regime has been recently perturbed, resulting in high denudation rates. A possible explanation would be the increase in precipitation less than 5 ka proposed by recent paleoclimatic studies. Our results indicate that erosion responds rapidly to high-frequency climatic fluctuations.

  15. Minimum speed limit for ocean ridge magmatism from 210Pb-226Ra-230Th disequilibria.

    PubMed

    Rubin, K H; van der Zander, I; Smith, M C; Bergmanis, E C

    2005-09-22

    Although 70 per cent of global crustal magmatism occurs at mid-ocean ridges-where the heat budget controls crustal structure, hydrothermal activity and a vibrant biosphere-the tempo of magmatic inputs in these regions remains poorly understood. Such timescales can be assessed, however, with natural radioactive-decay-chain nuclides, because chemical disruption to secular equilibrium systems initiates parent-daughter disequilibria, which re-equilibrate by the shorter half-life in a pair. Here we use 210Pb-226Ra-230Th radioactive disequilibria and other geochemical attributes in oceanic basalts less than 20 years old to infer that melts of the Earth's mantle can be transported, accumulated and erupted in a few decades. This implies that magmatic conditions can fluctuate rapidly at ridge volcanoes. 210Pb deficits of up to 15 per cent relative to 226Ra occur in normal mid-ocean ridge basalts, with the largest deficits in the most magnesium-rich lavas. The 22-year half-life of 210Pb requires very recent fractionation of these two uranium-series nuclides. Relationships between 210Pb-deficits, (226Ra/230Th) activity ratios and compatible trace-element ratios preclude crustal-magma differentiation or daughter-isotope degassing as the main causes for the signal. A mantle-melting model can simulate observed disequilibria but preservation requires a subsequent mechanism to transport melt rapidly. The likelihood of magmatic disequilibria occurring before melt enters shallow crustal magma bodies also limits differentiation and heat replenishment timescales to decades at the localities studied. PMID:16177787

  16. Using U-series and beryllium isotopes to reveal the occurrence and relative timing of crustal and mantle processes in the Southern Volcanic Zone of Chile

    NASA Astrophysics Data System (ADS)

    Cooper, L. B.; Reubi, O.; Dungan, M. A.; Bourdon, B.; Langmuir, C. H.; Turner, S. J.; Schaefer, J. M.

    2012-12-01

    Magmas erupted from subduction zone volcanoes represent the end products of multiple magmatic processes occurring in the asthenospheric mantle wedge and overlying lithosphere (i.e., fluid addition, melting, assimilation, and crystal fractionation). To resolve the contributions of diverse processes and components, and the relative timing of these events, we have determined U-series activities (U-Th-Ra-Pa) for 60 and 10Be compositions for 20 historic or very young lavas carefully chosen on the basis of major and trace element analyses of 625 samples from six volcanoes in the Andean Southern Volcanic Zone of Chile (37.6-41.1S: Nevados de Chilln, Antuco, Llaima, Lonquimay, Villarrica, and Osorno). Our dataset demonstrates that each of these volcanoes reflects a unique combination and sequence of magmatic processes that are only revealed through analysis of multiple samples spanning the extent of intra-volcano and intra-eruption chemical variation. Sigmarsson et al. (1990; 2002) identified a regional trend using U-series and Be from mostly single samples, which they interpreted to represent along-strike variations in the flux of slab-derived fluids into the wedge [from 230Th-excess plus 226Ra-deficit plus low 10Be/9Be at Chilln towards progressively higher 238U- and Ra-excesses and 10Be/9Be at Villarrica and Osorno]. These data fall within the much broader array defined by our results, but we infer the operation of assimilation (e.g., Llaima; Reubi et al., 2011) and aging of subduction zone components of variable compositions and proportions in the mantle prior to partial melting as important factors in generating the highly individualized and complex U-series systematics observed at each of these six volcanoes. All of the volcanoes exhibit evidence of assimilation, with the exception of Lonquimay which has undergone mostly closed-system fractional crystallization. At Llaima and Chilln the assimilant is crustal. At Villarica, flux-related melts that dominate in the main edifice have been mixed with magma compositions similar to those at surrounding minor eruptive centers (Hickey-Vargas et al., 2002). The latter appear to be decompression melts of enriched mantle which manifest moderate U-Th-Ra disequilibrium and substantial 231Pa-excesses, whereas melts from Villarrica have substantial U- and Ra-excesses. Magmas from Osorno reflect a greater influence of sediments originating from the incoming slab. After discounting assimilated samples, all primary melts have uniformly high Pa-excesses (1.7-2.2) coincident with large variations in 238U-230Th disequilibria. Fluid addition-aging-melting successions at Antuco and Chilln may have led to compositions near U-Th equilibrium or with Th-excesses, respectively. Primary Ra-deficits at Chilln, Lonquimay, and Osorno are under investigation and potentially reflect melting of a cumulate body. Forthcoming 10Be data for select U-series samples will enable further clarification of the regional trend. Preliminary analyses of nine Llaima samples erupted between 1850 and 2009 confirm the successful elimination of a meteoric 10Be component and produce a data array consistent with assimilation. The invocation of radioactive decay to produce U-Th equilibrium (duration of at least 380 ky) could also explain the low 10Be/9Be compositions (half-life of 10Be=1,390 ky). Our comprehensive dataset may shed new light on melting processes in subduction zone systems.

  17. Theoretical studies of {sup 238}U-{sup 230}Th-{sup 226}Ra and {sup 235}U-{sup 231}Pa disequilibria in young lavas produced by mantle melting

    SciTech Connect

    Zou, H.; Zindler, A.

    2000-05-01

    This paper provides ready-to-use equations to describe variations in uranium-series (U-series) disequilibrium as a function of elemental distribution coefficients, melting porosity, melting rate, and melting time. The effects of these melting parameters on U-series disequilibria are quantitatively evaluated in both an absolute and relative sense. The importance of net elemental fractionation and ingrowth of daughter nuclides are also described and compared in terms of their relative contributions to total U-series disequilibrium. In addition, the authors compare the production of U-series disequilibrium during mantle melting to trace element fractionations produced by melting in a similar context. Trace element fractionations depend externally on the degree to which a source is melted, whereas U-series disequilibrium depends upon both the degree and rate of melting. In contrast to previous models, their approach to modeling U-series disequilibrium during dynamic melting collapses simply to a description of trace element behavior during dynamic melting when the appropriate decay terms are omitted. Their formulation shows that extremely small degrees of melting, sometimes called upon to explain observed extents of U-series disequilibrium, are not always required.

  18. Plume-ridge interaction studied at the Galápagos spreading center: Evidence from 226Ra- 230Th- 238U and 231Pa- 235U isotopic disequilibria

    NASA Astrophysics Data System (ADS)

    Kokfelt, Thomas Find; Lundstrom, Craig; Hoernle, Kaj; Hauff, Folkmar; Werner, Reinhard

    2005-05-01

    New 238U- 230Th- 226Ra and 231Pa- 235U disequilibria data measured by TIMS are presented for ridge-centered MORB glasses dredged during the R/V Sonne 158 cruise at the Galápagos or Cocos-Nazca Spreading Center (GSC) between 86.0°W and 92.3°W. The application of U-series isotopes to the GSC region, situated a few hundred kilometres to the north of the Galápagos hotspot, allows assessment of fundamental questions related to the dynamics of plume-ridge interaction. These include (1) the relationship between long-lived source variations, U-series disequilibria and extent of differentiation, (2) partial melting during solid upwelling, and (3) the nature and rates of plume-ridge mass transfer. The along axis U-series disequilibria variation show gradational patterns that locally are correlated with geochemical and isotopic parameters such as La/Sm, Tb/Yb, 206Pb/ 204Pb and 143Nd/ 144Nd as well as major element compositions. The correlation of ( 230Th)/( 238U) with radiogenic isotopes and Tb/Yb provides constraints on the plume source influence on the melting process, reflecting an increase in the amount of melting at depth in the presence of garnet or aluminous clinopyroxene. Moreover, the correlation between U-series signatures, radiogenic isotopes, incompatible element abundance and MgO content indicates a causative relationship between the melting of plume source materials and how these lavas differentiate at shallow depths. We speculate that this involves loss of alkalis from ascending melts to shallow peridotite and crustal gabbro, resulting in increased olivine fractionation from the magmas. The U-series data place stringent constraints on the timing of plume-ridge mass transfer and thus distinguish whether mass transfer occurs by movement of melts or solid mantle. Within the likely conditions proposed by the model of (Braun and Sohn [EPSL 213 (2003): 417-430] and with knowledge of ( 231Pa)/( 235U) and ( 230Th)/( 238U) observed in Galápagos Islands lavas [A. Saal, personal communication], we show that all 226Ra excess will be lost and the initial 231Pa and 230Th excesses will be largely decayed. Therefore, we conclude that the plume influence on the GSC lavas results from a solid mantle flow process instead of through migration of plume-derived melts to the ridge.

  19. Saprolite Formation Rates using U-series Isotopes in a Granodiorite Weathering Profile from Boulder Creek CZO (Colorado, USA)

    NASA Astrophysics Data System (ADS)

    Pelt, Eric; Chabaux, Francois; Mills, T. Joseph; Anderson, Suzanne P.; Foster, Melissa A.

    2015-04-01

    Timescales of weathering profile formation and evolution are important kinetic parameters linked to erosion, climatic, and biological processes within the critical zone. In order to understand the complex kinetics of landscape evolution, water and soil resources, along with climate change, these parameters have to be estimated for many different contexts. The Betasso catchment, within the Boulder Creek Critical Zone Observatory (BC-CZO) in Colorado, is a mountain catchment in Proterozoic granodiorite uplifted in the Laramide Orogeny ca. 50 Ma. In an exposure near the catchment divide, an approximately 1.5 m deep profile through soil and saprolite was sampled and analysed for bulk U-series disequilibria (238U-234U-230Th-226Ra) to estimate the profile weathering rate. The (234U/238U), (230Th/234U) and (226Ra/230Th) disequilibria through the entire profile are small but vary systematically with depth. In the deepest samples, values are close to equilibrium. Above this, values are progressively further from equilibrium with height in the profile, suggesting a continuous leaching of U and Ra compared to Th. The (234U/238U) disequilibria remain < 1 along the profile, suggesting no significant U addition from pore waters. Only the shallowest sample (~20 cm depth) highlights a 226Ra excess, likely resulting from vegetation cycling. In contrast, variations of Th content and (230Th/232Th) - (238U/232Th) activity ratios in the isochron diagram are huge, dividing the profile into distinct zones above and below 80 cm depth. Below 80 cm, the Th content gradually increases upward from 1.5 to 3.5 ppm suggesting a relative accumulation linked to chemical weathering. Above 80 cm, the Th content jumps to ~15 ppm with a similar increase of Th/Ti or Th/Zr ratios that clearly excludes the same process of relative accumulation. This strong shift is also observed in LREE concentrations, such as La, Ce and Nd, and in Sr isotopic composition, which suggests an external input of radiogenic material such as dust from the western Colorado deserts or eroding landscapes. For the deeper part of the profile, the strong upward decrease of the (230Th/232Th) and (238U/232Th) activity ratio without generation of strong disequilibria could suggest a long history (~0.5-1 Ma) of U leaching with a very slow saprolite development (~1 m/Ma). Such a result is in agreement with slow weathering rates deduced from modern solute chemistry of rivers, but would be much lower than 10Be denudation rates on the same profile of ~10-20 m/Ma. As the 10Be rates integrate denudation over a timescale of 40-80 ka, the apparent inconsistency between rates deduced by U-series data and Be data might suggest that erosion rates have increased during the 10Be integrating time.

  20. Determination of sedimentary transfer time from U-series nuclides:implications from the study of the Gandak river sediments

    NASA Astrophysics Data System (ADS)

    Bosia, Clio; Chabaux, Francois; France-Lanord, Christian; Deloule, Etienne; Pelt, Eric

    2014-05-01

    In previous studies, it was proposed to constrain sediments transfer time in alluvial plains by analyzing the variations of the U-series disequilibria in river sediments along the stream. This approach was illustrated in the case of the Ganges-Brahmaputra basin and it allowed defining a sediment transfer scenario that includes significantly different transfer times within the alluvial plain. These studies suggest that the transfer times depend on the sediment grain size: short transfer times for fine-grained sediments (a few ky or less) and much longer ones for coarse-grained sediments (100 ky or more - [1-4]). However, those estimations can be questioned in the light of recent studies based on the analysis of cosmonuclides [5] and Sr et Nd isotopes [6] , that suggest shorter transfer times (respectively 1-2 ky and less for the second study) for coarse-grained sediments in Himalayan streams. In order to better constrain the origin of the U-series disequilibria variations in river sediments, we performed a detailed study of the U-series nuclides in the sediments of the Gandak River, one of the main Ganges tributaries. This study involves the sampling during monsoon period of suspended sediments, collected at different depths of the water column in the downstream and upstream river sections. At the same time, a regular upstream-downstream sampling of riverbank sediments during non-monsoon period was conducted, with sediments collection on both riversides of a same sampling station. U-Th data obtained on whole rock samples outline the occurrence of significant 238U-230Th-226Ra disequilibria in river sediments, with however no simple upstream-downstream variation. The correlations observed between (238U/232Th) activity ratios and Ti/Th ratios as well as between (230Th/238U) ratios and (Nd, Ce, La, Sm)/Th ratios suggest that minor mineral phases, such as Ti-bearing minerals, monazite, zircon or xenotime, are likely to control a significant part of the U-Th-Ra budget in the Gandak sediments. U-isotopes fractionation could therefore not only depend on the chemical evolution of the sediments during its transfer within the plain and on the time evolution, but also on the mechanical transformation of the sediments mineralogical composition. This last aspect can be significantly influenced by local hydraulic conditions, inducing important sorting effects in river sediments. These results illustrate the interest to investigate separated mineral phases of river sediments. Indeed, we need to clarify the role of the mineral composition in the control of U-Th-Ra isotopic fractionation in river sediments. This is a key point to achieve more reliable transfer times, avoiding problems linked to environmental bias. [1] Chabaux et al., 2012, C. R. Geoscience, 344 (11-12): 688-703; [2] Chabaux et al., 2006, J. Geochem. Exploration, 88: 373-375 ; [3] Granet et al., 2010, Geochim. et Cosmoch. Acta, 74 (10): 2851-2865 ; [4] Granet et al., 2007, Earth and Planet. Sci. Lett., 261 (3-4): 389-406 ; [5] Lupker et al., 2012, Earth and Planet. Sci. Lett., 333-334: 146-156; [6] Rahaman et al., 2009, Geology, 37 (6): 559-562.

  1. Methods for obtaining sorption data from uranium-series disequilibria

    SciTech Connect

    Finnegan, D.L.; Bryant, E.A.

    1987-12-01

    Two possible methods have been identified for obtaining in situ retardation factors from measurements of uranium-series disequilibria at Yucca Mountain. The first method would make use of the enhanced {sup 234}U/{sup 238}U ratio in groundwater to derive a signature for exchangeable uranium sorbed on the rock; the exchangeable uranium would be leached and assayed. The second method would use the ratio of {sup 222}Rn to {sup 234}U in solution, corrected for weathering, to infer the retardation factor for uranium. Similar methods could be applied to thorium and radium.

  2. Non-destructive gamma spectrometric U-series dating

    NASA Astrophysics Data System (ADS)

    Simpson, John J.; Grn, Rainer

    Prehistoric hominid fossils are too valuable to be dated by destructive or even partially destructive methods. Non-destructive U-series dating by ?-ray counting can therefore be a valuable method if relatively large hominid fragments, such as skulls, containing measurable amounts of uranium are available. We present a description of the method as well as some results including those obtained from a previously dated coral as well as two Australian hominid skulls (WLH 50 and Mungo 3). The dating procedure is designed to minimise systematic errors which may easily overwhelm statistical errors if care is not taken. The gamma spectrometric results are in good agreement with alpha and mass spectrometric measurements as well as independent age determinations. The results show no evidence for any uranium uptake over longer time periods.

  3. Chemical Disequilibria and Sources of Gibbs Free Energy Inside Enceladus

    NASA Astrophysics Data System (ADS)

    Zolotov, M. Y.

    2010-12-01

    Non-photosynthetic organisms use chemical disequilibria in the environment to gain metabolic energy from enzyme catalyzed oxidation-reduction (redox) reactions. The presence of carbon dioxide, ammonia, formaldehyde, methanol, methane and other hydrocarbons in the eruptive plume of Enceladus [1] implies diverse redox disequilibria in the interior. In the history of the moon, redox disequilibria could have been activated through melting of a volatile-rich ice and following water-rock-organic interactions. Previous and/or present aqueous processes are consistent with the detection of NaCl and Na2CO3/NaHCO3-bearing grains emitted from Enceladus [2]. A low K/Na ratio in the grains [2] and a low upper limit for N2 in the plume [3] indicate low temperature (possibly < 273 K) of aqueous processes. Although many of the energetically favorable redox reactions are sluggish at low temperature, they could be catalyzed by enzymes if organisms were (are) present. The redox conditions in aqueous systems and amounts of available Gibbs free energy should have been affected by the production, consumption and escape of hydrogen. Aqueous oxidation of minerals (Fe-Ni metal, Fe-Ni phosphides, etc.) accreted on Enceladus should have led to H2 production, which is consistent with H2 detection in the plume [1]. Numerical evaluations based on concentrations of plume gases [1] reveal sufficient energy sources available to support metabolically diverse life at a wide range of activities (a) of dissolved H2 (log aH2 from 0 to -10). Formaldehyde, carbon dioxide [c.f. 4], HCN (if it is present), methanol, acetylene and other hydrocarbons have the potential to react with H2 to form methane. Aqueous hydrogenations of acetylene, HCN and formaldehyde to produce methanol are energetically favorable as well. Both favorable hydrogenation and hydration of HCN lead to formation of ammonia. Condensed organic species could also participate in redox reactions. Methane and ammonia are the final products of these putative redox transformations. Sulfates may have not formed in cold and/or short-term aqueous environments with a limited H2 escape. In contrast to Earth, Mars and Europa, the moon may have no (or very limited [4]) potential for sulfate reduction. Despite nutrient (C, N, P and S) and metal (e.g. Fe, Ni) rich environments and multiple sources of Gibbs free energy during aqueous episode(s), putative life on Enceladus [4] would have adapted to survive in low water activity alkaline brines rich in ammonia, methanol and organic liquids at temperature >150-170 K. The comet-like abundances of major plume gases and apparent redox disequilibria in aquatic systems are consistent with a minimal influence of aqueous processes on endogenic chemical reactions and may indicate abiotic interior. Alternatively, plume gases may represent never melted primordial parcels of the icy shell, while the deeper interior could contain altered species transformed in abiotic and/or biological processes. Refs: [1] Waite J. et al. (2009) Nature 460, 487-490. [2] Postberg F. et al. (2009) Nature 459, 1098-1101. [3] Hansen C. et al. (2010) 38th COSPAR Sci. Assembly. [4] McKay C. et al. (2008) Astrobiology 8, 909-919.

  4. Evaluation of Pleistocene groundwater flow through fractured tuffs using a U-series disequilibrium approach, Pahute Mesa, Nevada, USA

    USGS Publications Warehouse

    Paces, James B.; Nichols, Paul J.; Neymark, Leonid A.; Rajaram, Harihar

    2013-01-01

    Groundwater flow through fractured felsic tuffs and lavas at the Nevada National Security Site represents the most likely mechanism for transport of radionuclides away from underground nuclear tests at Pahute Mesa. To help evaluate fracture flow and matrix–water exchange, we have determined U-series isotopic compositions on more than 40 drill core samples from 5 boreholes that represent discrete fracture surfaces, breccia zones, and interiors of unfractured core. The U-series approach relies on the disruption of radioactive secular equilibrium between isotopes in the uranium-series decay chain due to preferential mobilization of 234U relative to 238U, and U relative to Th. Samples from discrete fractures were obtained by milling fracture surfaces containing thin secondary mineral coatings of clays, silica, Fe–Mn oxyhydroxides, and zeolite. Intact core interiors and breccia fragments were sampled in bulk. In addition, profiles of rock matrix extending 15 to 44 mm away from several fractures that show evidence of recent flow were analyzed to investigate the extent of fracture/matrix water exchange. Samples of rock matrix have 234U/238U and 230Th/238U activity ratios (AR) closest to radioactive secular equilibrium indicating only small amounts of groundwater penetrated unfractured matrix. Greater U mobility was observed in welded-tuff matrix with elevated porosity and in zeolitized bedded tuff. Samples of brecciated core were also in secular equilibrium implying a lack of long-range hydraulic connectivity in these cases. Samples of discrete fracture surfaces typically, but not always, were in radioactive disequilibrium. Many fractures had isotopic compositions plotting near the 230Th-234U 1:1 line indicating a steady-state balance between U input and removal along with radioactive decay. Numerical simulations of U-series isotope evolution indicate that 0.5 to 1 million years are required to reach steady-state compositions. Once attained, disequilibrium 234U/238U and 230Th/238U AR values can be maintained indefinitely as long as hydrological and geochemical processes remain stable. Therefore, many Pahute Mesa fractures represent stable hydrologic pathways over million-year timescales. A smaller number of samples have non-steady-state compositions indicating transient conditions in the last several hundred thousand years. In these cases, U mobility is dominated by overall gains rather than losses of U.

  5. 234U/238U Disequilibria along sedimentary discontinuities in a deep formation: late diagenetic U-relocation processes vs. large scale fluid circulation evidence ?

    NASA Astrophysics Data System (ADS)

    Deschamps, P.; Hillaire-Marcel, C.; Michelot, J.-L.; Doucelance, R.; Ghaleb, B.

    2003-04-01

    This work is part of geological investigations undertaken by the French Agency for Nuclear Waste Management (ANDRA) in order to study the safety of radioactive waste repository in deep geological clay layers. The target formation, from Mesozoic sedimentary rocks of the eastern Paris basin (France), is a thick (130--145 m), 400--500 m deep, Callovo-Oxfordian argilite unit, that is over- and underlain by Oxfordian and Bathonian limestones, respectively. Borehole core samples have been analysed for their uranium content and 234U/238U isotopic composition in order to examine the state of radioactive equilibrium existing between these two radionuclides naturally occurring in the rock. Any observations of disequilibrium should allow i) to document the mobility of these actinides in such deposits, and ii) to constrain the time scale of the geological phenomena responsible for it. Highly precise and accurate (234U/238U) analyses were obtained using Multiple Collector Inductively Coupled Plasma Mass Spectrometry. The overall reproducibility, including both chemical separation and spectrometric measurement, is about 0.15% (2?). Most samples of the target formation and its bounding rocks display secular equilibrium. However, in the Bathonian formation near the interface with the argilite layer, significant (234U/238U) disequilibria are observed along sub-horizontal sedimentary discontinuities, identified as styloliths, indicating that the process involved has been active during the last Ma. Isotopic and elemental compositions of uranium have been determined along a transect, perpendicular to a major discontinuity. The transect exhibits a symmetric pattern relative to this discontinuity with: (1) an increase of the U-concentration towards the stylolitic joint and (2) a sharp transition between significant (234U/238U) < 1 disequilibria in the stylolith to an excess of 234U ((234U/238U) = 1.05) in the vicinity of the joint, followed by a smooth decrease of the activity ratio away from the suture zone. Such disequilibria are commonly attributed to water/rock interaction phenomenon related to fluid circulation. In this case, mineralogical, trace and major element data rather indicate that the mechanism responsible for these disequilibria is epidiagenetic, directly associated with the presence of the stylolith, and likely due to micro-scale relocation of highly fractionated U. Therefore, the chemical system might be seen, at a larger scale, as a closed one. However, the phenomenon responsible for the recent reactivation of the stylolitization is not determined.

  6. Disequilibrium of the 238U series in basalt

    USGS Publications Warehouse

    Somayajulu, B.L.K.; Tatsumoto, M.; Rosholt, J.N.; Knight, R.J.

    1966-01-01

    Radioisotope analyses of basalt samples from Hawaii, Japan, and Iwo Jima show that: (1) 234U and 238U are virtually in radioactive equilibrium, (2) 230Th exceeds equilibrium values in all these samples, (3) 210Pb concentrations range from 10-200% of the equilibrium values and average 30% deficient, and (4) 226Ra is probably not in equilibrium with 234U. The source regions of the basalts or magma forming processes are open systems, chemically. The enrichment of some of the uranium-daughter nuclides is insufficient to account for the excess 206Pb in volcanic rocks. The isotopic composition of lead and specific activity of 210Pb in sublimates from Showa-shinzan, Japan are also reported. ?? 1966.

  7. 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

  8. The Genetics of DROSOPHILA SUBOBSCURA Populations. Xiv. Further Data on Linkage Disequilibria

    PubMed Central

    Loukas, M.; Krimbas, C. B.; Morgan, K.

    1980-01-01

    Data coming from one natural population of D. subobscura, that of Crete, are presented in detail and examined for nonrandom associations of genes and gene arrangements. This population and four others previously studied are reanalyzed for the detection of higher than first-order interactions. Only first-order interactions are important and statistically significant, especially those concerning genes and inversions in which these genes are included. The paucity of linkage disequilibria detected is remarkable, and we argue that it does not depend on the methods of study, rather it is genuine. We further argue that most of the disequilibria detected are probably due to mechanisms based on epistatic selection. PMID:17249049

  9. Thermal ionization mass spectrometry U-series dating of a hominid site near Nanjing, China

    NASA Astrophysics Data System (ADS)

    Zhao, Jian-Xin; Hu, Kai; Collerson, Kenneth D.; Xu, Han-Kui

    2001-01-01

    Mass spectrometric U-series dating of speleothems from Tangshan Cave, combined with ecological and paleoclimatic evidence, indicates that Nanjing Man, a typical Homo erectus morphologically correlated with Peking Man at Zhoukoudian, should be at least 580 k.y. old, or more likely lived during the glacial oxygen isotope stage 16 (620 ka). Such an age estimate, which is 270 ka older than previous electron spin resonance and alpha-counting U-series dates, has significant implications for the evolution of Asian H. erectus. Dentine and enamel samples from the coexisting fossil layer yield significantly younger apparent ages, that of the enamel sample being only less than one-fourth of the minimum age of Nanjing Man. This suggests that U uptake history is far more complex than existing models can handle. As a result, great care must be taken in the interpretation of electron spin resonance and U-series dates of fossil teeth.

  10. Evaluation of New Geological Reference Materials for U-Series Measurements

    NASA Astrophysics Data System (ADS)

    Denton, J. S.; Goldstein, S. J.; Nunn, A. J.; Ui Chearnaigh, K.; Amato, R.; Murrell, M. T.

    2012-12-01

    Uranium-series analytical measurements are widely used in geochemistry, geochronology, paleoclimatology, volcanology, environmental risk assessment and other fields. Recent advances in high-resolution, rapid, in situ microanalytical techniques e.g. LA-ICP-MS and SIMS present numerous opportunities for the geoanalytical community. As with other analytical techniques, the quality of the elemental concentration and isotopic data obtained through microanalytical techniques is dependent on the accurate characterization of suitable reference materials. Even for the case of fs-laser ablation applications, a range of well-characterized standards are required for high precision U-series work. Advances have been made in evaluating existing standard reference materials for U-series isotopic analysis, but this work is ongoing as more reference materials become available. In this study we present MC-TIMS and MC-ICP-MS results for uranium and thorium isotopic ratios and elemental concentrations measured in a suite of newly available Chinese Geological Standard Glasses (CGSG) designed for microanalysis. These glasses exhibit a range of chemical compositions including basalt, syenite, andesite and a soil. U concentrations for these glasses range from ?2 to 14 ?g/g and [Th]/[U] ratios range from ?4 to 6. Uranium and thorium concentration and isotopic data will also be presented for rhyolitic obsidian from Macusani, SE Peru, which can be used as a rhyolitic reference material. These high-precision and high-accuracy ratios, from a suite of standards that exhibit a range of natural, non-basaltic compositions, will complement data from existing standards and expand the catalogue of reference materials that are appropriate for in situ U-series work. These results can be used to assess the performance of microanalytical techniques and will facilitate inter-laboratory comparison of data within the broader geoscience community.

  11. U-series dating of Locality 15 at Zhoukoudian, China, and implications for hominid evolution

    NASA Astrophysics Data System (ADS)

    Shen, Guanjun J.; Gao, Xing; Zhao, Jian-xin; Collerson, Kenneth D.

    2004-09-01

    This paper reports U-series dates on speleothem samples from Locality 15 at Zhoukoudian, one of the richest Paleolithic sites in northern China. The age of the lower part of Layer 2 is securely bracketed between 155,000 and 284,000 yr. The underlying Layer 3 dates back at least 284,000 yr. Layer 4, further below, should be older still, possibly by a cycle on the SPECMAP time scale before 284,000 yr ago. These ages, much greater than the previous estimates of 110,000-140,000 yr from U-series and electron spin resonance dating of fossil teeth, suggest that Locality 15 was broadly contemporaneous with Locality 4 (New Cave) and with the uppermost strata of Locality 1 (Peking Man site). The physical evolution and cultural development evidenced by the timing of the Zhoukoudian localities are in line with the opinion of Chinese anthropologists for a regional transition from Homo erectus to archaic Homo sapiens.

  12. U-series dating of impure carbonates: An isochron technique using total-sample dissolution

    USGS Publications Warehouse

    Bischoff, J.L.; Fitzpatrick, J.A.

    1991-01-01

    U-series dating is a well-established technique for age determination of Late Quaternary carbonates. Materials of sufficient purity for nominal dating, however, are not as common as materials with mechanically inseparable aluminosilicate detritus. Detritus contaminates the sample with extraneous Th. We propose that correction for contamination is best accomplished with the isochron technique using total sample dissolution (TSD). Experiments were conducted on artificial mixtures of natural detritus and carbonate and on an impure carbonate of known age. Results show that significant and unpredictable transfer of radionuclides occur from the detritus to the leachate in commonly used selective leaching procedures. The effects of correcting via leachate-residue pairs and isochron plots were assessed. Isochrons using TSD gave best results, followed by isochron plots of leachates only. ?? 1991.

  13. U-series dating and stable isotope records of speleothem records from the Scladina Cave (Belgium)

    NASA Astrophysics Data System (ADS)

    van der Lubbe, Jeroen; Bonjean, Dominique; Hellstrom, John; Verheyden, Sophie; Vonhof, Hubert

    2015-04-01

    The Scladina cave, situated in the village of Sclayn (Ardennes, Belgium) at the southern bank of the Meuse, is famous for its Neanderthal fossils and artefacts. The infilling of the cave consists of a succession of flowstone layers interbedded with reworked loess sediment from outside the cave. The younger flowstone layers correspond to interglacials MIS 5 and the Holocene, while the reworked loess sediments represent cooler conditions. By careful diagenetic screening, well-preserved speleothem material was selected for U-series dating and stable isotope analysis of calcite and fluid inclusions. The results provide important new constraints on the age of Neanderthal fossils and artefacts, and bracket the time periods with a hydroclimate favorable for speleothem growth. The combination of fluid inclusion and calcite isotope analysis documents climate variability in the interglacials at high temporal resolution.

  14. /sup 234/Th: /sup 238/U disequilibria within the California Current

    SciTech Connect

    Coale, K.H.; Bruland, K.W.

    1985-01-01

    Profiles of dissolved and particulate /sup 234/Th were determined at several stations within the California Current. Modeling of the disequilibria between the /sup 234/Th and /sup 238/U within the surface waters provides for estimates of the residence time of dissolved thorium with respect to particle scavenging, the particle residence time, and the particulate /sup 234/Th flux exiting the surface layer. The model-derived, first-order scavenging rate constant for dissolved thorium is observed to be proportional to the rate of primary production. Particle residence times seem to be governed by the rate of zooplankton grazing and the types of zooplankton present. Model-derived particulate /sup 234/Th fluxes are in good agreement with direct measurements by sediment traps.

  15. Pressure disequilibria induced by rapid valve closure in noble gas extraction lines

    NASA Astrophysics Data System (ADS)

    Morgan, Leah E.; Davidheiser-Kroll, Brett

    2015-06-01

    Pressure disequilibria during rapid valve closures can affect calculated molar quantities for a range of gas abundance measurements (e.g., K-Ar geochronology, (U-Th)/He geochronology, noble gas cosmogenic chronology). Modeling indicates this effect in a system with a 10 L reservoir reaches a bias of 1% before 1000 pipette aliquants have been removed from the system, and a bias of 10% before 10,000 aliquants. Herein we explore the causes and effects of this problem, which is the result of volume changes during valve closure. We also present a solution in the form of an electropneumatic pressure regulator that can precisely control valve motion. This solution reduces the effect to 0.3% even after 10,000 aliquants have been removed from a 10 L reservoir.

  16. U-series evidence for crustal involvement and magma residence times in the petrogenesis of Parinacota volcano, Chile

    NASA Astrophysics Data System (ADS)

    Bourdon, B.; Wrner, G.; Zindler, A.

    In this study, we present Th-U disequilibria as well as radiogenic and trace element data for recent volcanic rocks from the Nevados de Payachata volcano which erupted through 70km of continental crust in the Central Volcanic Zone of the Andes (18S, 69W). Both lavas and mineral separates were analyzed by mass spectrometry for 238U-230Th disequilibria. The lavas are characterized either by 230Th enrichment or depletion relative to its parent nuclide 238U. Mineral separates are used to derive U-Th isochron ages and these ages compare favorably with inferred stratigraphic ages or K-Ar ages, although in one case the U-Th age is significantly older than the stratigraphic age. Despite relatively constant Sr, Nd, and Pb isotope ratios, the lavas display inverse trends in 230Th/238U versus Ce/Yb or Ba/Hf diagrams. These trends cannot be interpreted by simple two-component mixing. Rather, there must be three (and perhaps four components) involved in the genesis of the Parinacota lavas. A mantle wedge, a slab fluid, and a lower crustal component can be identified. A sediment component is more difficult to detect as it is difficult to decipher its signature because of the strong crustal influence. The existence of binary arrays can be explained by variable amounts of crustal material. The process of crust-mantle interaction must have been short enough to preserve U-Th disequilibrium (<300ka).

  17. Carbonate mound evolution and coral diagenesis viewed by U-series dating of deep water corals

    NASA Astrophysics Data System (ADS)

    Frank, N.; Ricard, E.; Blamart, D.; van der Land, C.; Colin, C.; Foubert, A.; van Rooij, D.; van Weering, T.

    2007-12-01

    U-series dating of constructional deep sea corals is a powerful tool to reconstruct the evolution of carbonate mound sediments driven by coral growth, sediment trapping and diagenesis. Here we have investigated in great detail the time framework of constructional corals such as L. pertusa and M. oculata on 5 different mounds of the eastern North Atlantic (on Rockall Bank and in Porcupine Seabight) taken at variable depth and location (610 to 880m water depth). Periods favorable for coral growth are the Holocene and prior interglacials such as marine isotope stage 5 and 7, while glacial coral growth seems inhibited or extremely reduced. Coral development is almost continuous throughout the Holocene since mound re-colonization about 10,500 years ago. Mound accumulation rates vary between 20 and 220 cm/kyr determined from the coral age - depth relationship in each core. Those changes are most likely driven by changes between horizontal and vertical mound accumulation, food supply and ocean circulation. In addition, coral dating allowed to identify an important erosional event recorded in core MD01-2455G from Rockall Bank. Here a 1m thick sediment layer containing ancient corals likely from the start of Holocene re-colonization was displaced (collapsed) from further upslope on top of younger corals of ~2500 to 3000 years age. Prior to the initiation of coral growth diagenesis occurred frequently resulting in (1) the construction of so called carbonate hardgrounds and/or (2) the dissolution of the pre-Holocene coral framework. Solely, the deepest selected core in Porcupine Seabight (MD01-2463G at 880m depth) reveals coral re-colonization on an undisturbed ancient reef structure that dates back to 250,000 years. Diagenesis of earlier coral reef generations leading to coral dissolution leads to a loss of magnetic susceptibility and open system behavior of the coral skeletons with respect to U-series dating. While the processes causing such diagenetic layers are barely understood the disappearance of the magnetic susceptibility can be used to trace such phenomena and a conserved magnetic susceptibility allows sampling of well preserved corals.

  18. Mid-ocean ridge basalt generation along the slow-spreading, South Mid-Atlantic Ridge (5-11°S): Inferences from 238U-230Th-226Ra disequilibria

    NASA Astrophysics Data System (ADS)

    Turner, Simon; Kokfelt, Thomas; Hauff, Folkmar; Haase, Karsten; Lundstrom, Craig; Hoernle, Kaj; Yeo, Isobel; Devey, Colin

    2015-11-01

    U-series disequilibria have provided important constraints on the physical processes of partial melting that produce basaltic magma beneath mid-ocean ridges. Here we present the first 238U-230Th-226Ra isotope data for a suite of 83 basalts sampled between 5°S and 11°S along the South Mid-Atlantic Ridge. This section of the ridge can be divided into 5 segments (A0-A4) and the depths to the ridge axis span much of the global range, varying from 1429 to 4514 m. Previous work has also demonstrated that strong trace element and radiogenic isotope heterogeneity existed in the source regions of these basalts. Accordingly, this area provides an ideal location in which to investigate the effects of both inferred melt column length and recycled materials. 226Ra-230Th disequilibria indicate that the majority of the basalts are less than a few millennia old such that their 230Th values do not require any age correction. The U-Th isotope data span a significant range from secular equilibrium up to 32% 230Th excess, also similar to the global range, and vary from segment to segment. However, the (230Th/238U) ratios are not negatively correlated with axial depth and the samples with the largest 230Th excesses come from the deepest ridge segment (A1). Two sub-parallel and positively sloped arrays (for segments A0-2 and A3 and A4) between (230Th/238U) and Th/U ratios can be modelled in various ways as mixing between melts from peridotite and recycled mafic lithologies. Despite abundant evidence for source heterogeneity, there is no simple correlation between (230Th/238U) and radiogenic isotope ratios suggesting that at least some of the trace element and radiogenic isotope variability may have been imparted to the source regions >350 kyr prior to partial melting to produce the basalts. In our preferred model, the two (230Th/238U) versus Th/U arrays can be explained by mixing of melts from one or more recycled mafic lithologies with melts derived from chemically heterogeneous peridotite source regions.

  19. New U-series dates at the Caune de l'Arago, France

    USGS Publications Warehouse

    Falgueres, Christophe; Yokoyama, Y.; Shen, G.; Bischoff, J.L.; Ku, T.-L.; de Lumley, Henry

    2004-01-01

    In the beginning of the 1980s, the Caune de l'Arago was the focus of an interdisciplinary effort to establish the chronology of the Homo heidelbergensis (Preneandertals) fossils using a variety of techniques on bones and on speleothems. The result was a very large spread of dates particularly on bone samples. Amid the large spread of results, some radiometric data on speleothems showed a convergence in agreement with inferences from faunal studies. We present new U-series results on the stalagmitic formation located at the bottom of Unit IV (at the base of the Upper Stratigraphic Complex). Samples and splits were collaboratively analyzed in the four different laboratories with excellent interlaboratory agreement. Results show the complex sequence of this stalagmitic formation. The most ancient part is systematically at internal isotopic equilibrium (>350 ka) suggesting growth during or before isotopic stage 9, representing a minimum age for the human remains found in Unit III of the Middle Stratigraphical Complex which is stratigraphically under the basis of the studied stalagmitic formation. Overlaying parts of the speleothem date to the beginning of marine isotope stages 7 and 5. ?? 2003 Elsevier Ltd. All rights reserved.

  20. New U-series dates at the Caune de l'Arago, France

    USGS Publications Warehouse

    Falgueres, Christophe; Yokoyama, Y.; Shen, G.; Bischoff, J.L.; Ku, T.-L.; de Lumley, Henry

    2004-01-01

    In the beginning of the 1980s, the Caune de l'Arago was the focus of an interdisciplinary effort to establish the chronology of the Homo heidelbergensis (Preneandertals) fossils using a variety of techniques on bones and on speleothems. The result was a very large spread of dates particularly on bone samples. Amid the large spread of results, some radiometric data on speleothems showed a convergence in agreement with inferences from faunal studies. We present new U-series results on the stalagmitic formation located at the bottom of Unit IV (at the base of the Upper Stratigraphic Complex). Samples and splits were collaboratively analyzed in the four different laboratories with excellent interlaboratory agreement. Results show the complex sequence of this stalagmitic formation. The most ancient part is systematically at internal isotopic equilibrium (>350 ka) suggesting growth during or before isotopic stage 9, representing a minimum age for the human remains found in Unit III of the Middle Stratigraphical Complex which is stratigraphically under the basis of the studied stalagmitic formation. Overlaying parts of the speleothem date to the beginning of marine isotope stages 7 and 5. ?? 2003 Elsevier Science Ltd. All rights reserved.

  1. ESR, U-series and paleomagnetic dating of Gigantopithecus fauna from Chuifeng Cave, Guangxi, southern China

    NASA Astrophysics Data System (ADS)

    Shao, Qingfeng; Wang, Wei; Deng, Chenglong; Voinchet, Pierre; Lin, Min; Zazzo, Antoine; Douville, Eric; Dolo, Jean-Michel; Falguères, Christophe; Bahain, Jean-Jacques

    2014-07-01

    Several Gigantopithecus faunas associated with taxonomically undetermined hominoid fossils and/or stone artifacts are known from southern China. These faunas are particularly important for the study of the evolution of humans and other mammals in Asia. However, the geochronology of the Gigantopithecus faunas remains uncertain. In order to solve this problem, a program of geochronological studies of Gigantopithecus faunas in Guangxi Province was recently initiated. Chuifeng Cave is the first studied site, which yielded 92 Gigantopithecus blacki teeth associated with numerous other mammalian fossils. We carried out combined ESR/U-series dating of fossil teeth and sediment paleomagnetic studies. Our ESR results suggest that the lower layers at this cave can be dated to 1.92 ± 0.14 Ma and the upper layers can be dated to older than 1.38 ± 0.17 Ma. Correlation of the recognized magnetozones to the geomagnetic polarity timescale was achieved by combining magnetostratigraphic, biostratigraphic and ESR data. The combined chronologies establish an Olduvai subchron (1.945-1.778 Ma) for the lowermost Chuifeng Cave sediments. We also analyzed the enamel δ13C values of the Gigantopithecus faunas. Our results show that southern China was dominated by C3 plants during the early Pleistocene and that the Gigantopithecus faunas lived in a woodland-forest ecosystem.

  2. U-series ages of solitary corals from the California coast by mass spectrometry

    SciTech Connect

    Stein, M.; Wasserburg, G.J.; Chen, J.H. ); Lajoie, K.R. )

    1991-12-01

    The purpose of this study is to evaluate the feasibility of dating fossil solitary corals from Pleistocene marine strandlines outside tropical latitudes using the recently developed high sensitivity, high-precision U-series technique based on thermal-ionization mass-spectrometry (TIMS). The TIMS technique is much more efficient than conventional {alpha} spectrometry and, as a result, multiple samples of an individual coral skeleton, or different specimens from the same bed can be analyzed. Detached and well-rounded fossil specimens of the solitary coral Balanophyllia elegans were collected from relict littoral deposits on emergent marine terraces along the California coast at Cayucos terrace, Shell Beach terrace, Nestor terrace, San Diego, Bird Rock terrace, San Diego. Attached living specimens were collected from the intertidal zone on the modern terrace at Moss Beach. The calculated initial {sup 234}U activities in the fossil specimens of Balanophyllia elegans are higher than the {sup 234}U activity in modern seawater or in the modern specimen. The higher initial activities could possibly reflect the influx of {sup 234}U-enriched continental water into Pleistocene coastal waters, or it could reflect the influx of {sup 234}U-enriched continental water into Pleistocene coastal waters, or it could reflect minor diagenetic alteration, a persistent and fundamental problem in dating all corals.

  3. ESR and U-series analyses of teeth from the palaeoanthropological site of Hexian, Anhui Province, China.

    PubMed

    Grn, R; Huang, P H; Huang, W; McDermott, F; Thorne, A; Stringer, C B; Yan, G

    1998-06-01

    ESR and U-series analyses of teeth from the palaeoanthropological site of Hexian which contained Homo erectus remains, illustrate the limited effectiveness of stand-alone ESR and U-series age estimates on faunal materials. The problem lies in the unknown U-uptake history causing very large uncertainties in the age results of both techniques. This study demonstrates the particular strength that lies in the integration of ESR and U-series dating analyses allowing the estimation of the U-uptake history. We obtained a combined ESR/U-series age estimate of 412 +/- 25 ka (average of six analyses on two teeth). This pinpoints the deposition of the faunal remains to the time of the transition between oxygen isotope stages 12 and 11. This is in agreement with the faunal composition which show a mixture of cold adapted northern mammals and more subtropical-tropical southern elements. The age also implies that the advanced Hexian Homo erectus occurred at a similar time as the less advanced Homo erectus specimens at Locality 1 at Zhoukoudian (LI-LIII). PMID:9650100

  4. U-series constraints on the Holocene human presence in the Cuatro Cienegas basin, Mexico

    NASA Astrophysics Data System (ADS)

    Noble, S. R.; Felstead, N.; Gonzalez, S.; Leng, M. J.; Metcalfe, S. E.; Patchett, P. J.

    2010-12-01

    U-series tufa ages dating a human trackway have been obtained, part of a larger Late Pleistocene - Recent palaeoclimate and human occupation study of the Cuatro Cienegas basin, NE Mexico. Our analytical approach, including tracer calibration, couples aspects of what we consider best practice in the U-series community with our U-Pb experiences which includes the EarthTime U-Pb tracer calibration exercise. The recently discovered trackway is near a small hydrothermal pool within the basin [1], an ecologically highly significant oasis in the Chihuahuan desert. The oasis comprises >200 freshwater hydrothermal pools and a river system, and the related ecosystem hosts >70 endemic species[2]. Pools are fed by waters that circulate a deep karstic system and that originate in the surrounding upper Jurassic-lower Cretaceous Sierra Madre Oriental mountains (>3000m) [3]. The area hosted nomadic hunter-gatherers during the Holocene, and possibly as early as Late Pleistocene (~12 ka BP). Despite the basin's ecological significance, only three palaeoenvironmental studies have been published to date, and limited geochronological constraints are available. A pollen study of drill core through peats and tufas proximal to the pools suggested a long period of climatic stability and biogeographic isolation[4], a notion supported by the large number of endemic species, but other palynological and plant macrofossil data suggest that large climatic changes occurred post Late Pleistocene [5]. The 10 m long in situ trackway is preserved in tufa and five samples from the uppermost surfaces were analysed to date the footprints. The tufas comprise clean carbonate with no petrographic evidence of replacement and little contaminant detrital material (on some exposed upper surfaces). Powdered tufa was processed following [6-8], and analysed by TIMS (Triton, U) and MC-ICP-MS (Th, Nu HR), although our future analyses will primarily be obtained on a Neptune. Samples were spiked with a 229Th/236U tracer calibrated against gravimetric solutions prepared from Ames high-purity Th metal crystal and CRM 112a U metal ingot rather than natural materials of assumed secular equilibrium. ICP-MS mass bias and Faraday-SEM gain was monitored using CRM 112a and an in-house 229Th-230Th-232Th solution. Most samples have relatively high U contents (~2 ppm U), moderate [230Th/232Th] = 29-44, and initial [234U/238U] ~ 1.92. We obtain an age of 7.24 0.13 ka BP for this trackway based on an average of two samples of the uppermost tufa surface. Depth profiling of one sample shows consistently increasing age downwards (~370 a/cm). [1] Gonzalez, A.H.G. et al., 2006, Ichnos 16, 12-24;[2] Souza, V. et al., 2006, PNAS 103, 6565-6570; [3] Johannesson, K.H. et al., 2004, J.S.Am.Earth Sci. 17, 171-180; [4] Meyer, E. 1973, Ecology 54, 982-995; [5] Minckley, T.A. & Jackson, S. 2008. J. Biogeography 35, 188-190; [6] Edwards, R.L. et al., 1987, EPSL 81, 175-192; [8] Cheng, H. et al., 2000, Chem. Geol. 169, 17-33; [8] Potter, E.K. et al., 2005, EPSL 247, 10-17.

  5. Regolith formation rate from U-series nuclides: Implications from the study of a spheroidal weathering profile in the Rio Icacos watershed (Puerto Rico)

    NASA Astrophysics Data System (ADS)

    Chabaux, F.; Blaes, E.; Stille, P.; di Chiara Roupert, R.; Pelt, E.; Dosseto, A.; Ma, L.; Buss, H. L.; Brantley, S. L.

    2013-01-01

    A 2 m-thick spheroidal weathering profile, developed on a quartz diorite in the Rio Icacos watershed (Luquillo Mountains, eastern Puerto Rico), was analyzed for major and trace element concentrations, Sr and Nd isotopic ratios and U-series nuclides (238U-234U-230Th-226Ra). In this profile a 40 cm thick soil horizon is overlying a 150 cm thick saprolite which is separated from the basal corestone by a 40 cm thick rindlet zone. The Sr and Nd isotopic variations along the whole profile imply that, in addition to geochemical fractionations associated to water-rock interactions, the geochemical budget of the profile is influenced by a significant accretion of atmospheric dusts. The mineralogical and geochemical variations along the profile also confirm that the weathering front does not progress continuously from the top to the base of the profile. The upper part of the profile is probably associated with a different weathering system (lateral weathering of upper corestones) than the lower part, which consists of the basal corestone, the associated rindlet system and the saprolite in contact with these rindlets. Consequently, the determination of weathering rates from 238U-234U-230Th-226Ra disequilibrium in a series of samples collected along a vertical depth profile can only be attempted for samples collected in the lower part of the profile, i.e. the rindlet zone and the lower saprolite. Similar propagation rates were derived for the rindlet system and the saprolite by using classical models involving loss and gain processes for all nuclides to interpret the variation of U-series nuclides in the rindlet-saprolite subsystem. The consistency of these weathering rates with average weathering and erosion rates derived via other methods for the whole watershed provides a new and independent argument that, in the Rio Icacos watershed, the weathering system has reached a geomorphologic steady-state. Our study also indicates that even in environments with differential weathering, such as observed for the Puerto Rico site, the radioactive disequilibrium between the nuclides of a single radioactive series (here 238U-234U-230Th-226Ra) can still be interpreted in terms of a simplified scenario of congruent weathering. Incidentally, the U-Th-Ra disequilibrium in the corestone samples confirms that the outermost part of the corestone is already weathered.

  6. Multiple Dehydration Events Beneath Island Arc, Evidence from U-Th-Ra Isotopic Disequilibria in Mt. Fuji Lavas, Japan.

    NASA Astrophysics Data System (ADS)

    Chekol, T.; Nakamura, E.

    2014-12-01

    Trace element, Sr-Nd isotopes compositions and U-Th-Ra isotopic disequilibria data are presented for Fuji basalts of the last 10,000 yr. Both Sr and Nd isotopes signatures of Fuji basalts show very narrow range (0.703276-0.703363 and 0.51304-0.51306, respectively), indicating that a homogenous mantle source beneath the volcano. All of the Fuji lavas have 238U-230Th disequilibrium with excesses of 238U. These signatures are typical for arc lavas and not MORB and OIB lavas. Samples from individual stages show linear trends having a trajectory cross the equiline at almost the same value at (230Th/232Th) = 0.84. This common line can thus be regarded as isochron age of ~90 kyr, representing the time intervals since the onset of the disequilibrium by metasomatism of the mantle wage by fluids released from the dehydrated subducting slab. However, (226Ra/230Th) activity ratios in Fuji lavas range from ~1 up to 3.2 indicating that less than 8000 yr elapsed since the generation of the disequilibria by metasomatism of the mantle wedge by fluids released from the subducting slab. Ba/Th ratio shows clear positive correlation with (238U/230Th) disequilibrium, however, it shows no correlation with (226Ra/230Th), instead remains constant for the whole range of (226Ra/230Th) disequilibria, indicating that the fluid that carried Ra was not carried Ba. Multiple dehydration events can be the preferred explanation in order to reconcile the U-Th and Ra-Th disequilibria age information. Therefore, dehydration reactions in the slab, some 90 kyr ago, were released fluids and transporting fluid-mobile elements Ra and U into the overlaying mantle wedge. Consequently, Ra and U depleted in the slab. But, 226Ra with time would have been continually formed in the slab by in-growth from the fluid-immobile 230Th that left after the first dehydration episode. As a result, any later fluid addition into the mantle wedge is capable of adding considerable amount of 226Ra but not extra U, so that the U-Th disequilibria recorded the first fluid addition event around 90 kyr.

  7. Middle Palaeolithic refugium, or archaeological misconception? A new U-Series and radiocarbon chronology of Abric Agut (Capellades, Spain)

    USGS Publications Warehouse

    Vaquero, Manola; Esteban, M.; Allue, E.; Vallverdu, J.; Carbonell, E.; Bischoff, J.L.

    2002-01-01

    New U-Series and C14 (AMS) dates are provided for the Abric Agut (Capellades, Barcelona, Spain). This site was previously considered to be of Middle Palaeolithic age according to the characteristics of the lithic assemblage. In addition, human teeth were uncovered and attributed to neandertals. However, radiometric dating clearly indicates a Late Pleistocene-Early Holocene age. ?? 2002 Elsevier Science Ltd. All rights reserved.

  8. U-Th-Ra disequilibria in sediments of the Dora Baltea river (Italia)

    NASA Astrophysics Data System (ADS)

    Chabaux, F.; Deloche, A.; Pelt, E.; Granet, M.; Perrone, Th.; Boutin, R.; Viville, D.; Rihs, S.; Stille, P.

    2012-04-01

    In order to constrain the transfer time of sediments in Alpine rivers, we propose to use the U-series nuclides approach recently developed for Himalayan rivers (e.g., Chabaux et al., 2008; Granet et al., 2010). Therefore, a series of bank sediments has beeen collected along the Dora Baltea river (Italia), one of the Po's tributaries draining the southern slope of the Mont Blanc Massif. In addition to U series nuclides, major and trace element concentrations and Sr and Nd isotope ratios have been analyzed for each sample. The study indicates that the (234U/238U)-, (230Th/234U)- and the (226Ra/230Th)- activity ratios are very similar for all the samples, whereas the 230Th/232Th ratios can differ from one sample to another. Such a variation, consistent with the Sr and Nd isotope data, is certainly the consequence of mineralogical heterogeneities in the samples. This suggests that the use of 238U-230Th-232Th systematics alone is probably insufficient for constraining the transfer time of sediments in the Po rivers alluvial plain, whereas the combination of 238U-230Th disequilibrium with the 230Th-226Ra disequilibrium can help to constrain such time information.

  9. 238U, 232Th profiling and U-series isotope analysis of fossil teeth by laser ablation-ICPMS

    NASA Astrophysics Data System (ADS)

    Eggins, Stephen; Grn, Rainer; Pike, Alistair W. G.; Shelley, Michael; Taylor, Lois

    2003-05-01

    U and Th concentration profiles in fossil hominid and faunal teeth have been measured by laser ablation ICPMS. These profiles record diverse modes of U and Th uptake, particularly within enamel, that can be broadly related to the state of sample preservation. Observed U profiles are in general inconsistent with existing diffusion-adsorption models developed for U-uptake in bone and teeth. Where the models appear applicable, calculated diffusion rates are several orders of magnitude smaller than previous estimates. Laser ablation ICPMS offers a means of rapidly characterizing U and Th distributions in the enamel and dentine components of teeth as a precursor to ESR and U-series dating. In particular, it should allow the identification of teeth (and also bone) samples that have simple U-uptake histories and are amenable to precise dating by time-consuming and expensive Th-U and Pa-U TIMS techniques. We also demonstrated the use of laser ablation ICPMS to measure U-series isotopes in dentine and enamel samples with relatively high U concentrations (>20 ppm). These results, obtained using a quadrupole ICPMS, illustrate significant promise for in situ U-series isotope analysis, particularly when combined with the greater sensitivity and multi-collection capabilities of new sector ICPMS instrumentation. The latter may permit precise isotope ratio measurements on samples containing only a few ppm of U.

  10. U-series data of recent volcanism at an Axial Volcanic Ridge (Invited)

    NASA Astrophysics Data System (ADS)

    van Calsteren, P. W.; Thomas, L. E.; Jc024 Shipboard Party

    2010-12-01

    The spreading rate of the Mid Atlantic Ridge, at the area around 45N is 11mm/y. This is appropriate scaling for mantle horizontal flow and vertical upwelling. However, the accretion of oceanic crust within the median valley graben (MVG), occurs episodically on timescales much longer than years. During the 2008 JC024 cruise various geophysical and bathymetry datasets were collected as well as photographic and video evidence and some 270 rock samples, using ship-borne instruments, a deep-towed platform TOBI and a tethered ROV Isis both in demersal mode and 'flying' at 100m above the seafloor. We1 could identify the overall 'hour-glass' shape of the MVG, the location of the AVR, 'flat-top' features and some smooth areas on either side. Overall we1 counted some 8000 conical or dome-shaped hummocks, which are arranged in lineaments, mostly parallel to the spreading axis. We1 deduced that each hummock is an individual monogenetic volcano. Smooth areas between the AVR and the median valley boundary faults may indicate sheet flows which are probably burying the subsiding hummocks. For Dive 91, we1 used a MS2000 high-resolution multi-beam bathymetry echo-sounder on Isis flying at an altitude of 100m above the seafloor; to construct a bathymetry map with a vertical resolution of 20cm and a horizontal precision of 5m over an area of 3km2. The high-resolution bathymetry allows us to deduce that volcano dimensions average around 300m diameter, 150m altitude, and 0.005km3 volume and to count 100 volcanoes. Visual observations using the camera systems on Isis showed that individual volcanoes are essentially piles of pillow lavas, usually 1m diameter and >2m long of various types, sometimes leaving >10% gaps between pillows, sometimes interlocking somewhat deformed pillows. Small protrusions, 10-50cm long, which are numerous on some pillows, could be fairly easily broken off using the pincers on the hydraulic arms of Isis, and returned to the surface. Uncertainty remains over the age of the AVR, or probably more appropriately, the time-span between to youngest and the oldest exposed rocks. Many indirect dating methods have been applied with inferred ages ranging from 10ky to 200ky. We1 applied the magnetic paleo-intensity method to infer an age of 12ky for the 45N AVR. We will report U-series based age calculations for samples from the Dive 91 area. The samples were taken from a number of individual volcanoes and the simplest expectation would be that the youngest samples are from the AVR crest with older ages down the flanks. However, crustal magnetisation intensity can be taken as a proxy for age and this1,3 indicates a more complex pattern of young ages in the volcanic lineaments away from the crest. Indeed, visual observations of rocks at up to 1km from the crest would indicate that those are equally fresh. Indeed, Standish and Sims2 have shown that young eruption ages are broadly dispersed throughout the rift valley of the ultra-slow spreading Southwest Indian Ridge at a range much wider than covered by the area of Dive 91. Construction of new volcanic crust solely at the crest of the AVR may well be too simplistic.

  11. U-series dating of pillow rim glass from recent volcanism at an Axial Volcanic Ridge

    NASA Astrophysics Data System (ADS)

    Thomas, L. E.; van Calsteren, P. W.; Jc024 Shipboard Party

    2010-12-01

    Visual observations using camera systems on the tethered ROV Isis deployed during the 2008 JC024 cruise to the Mid Atlantic Ridge at 45N showed1 numerous monogenetic volcanoes that are essentially piles of lava pillows. The pillows are usually 1m diameter and >2m long and form mounds with average dimensions around 300m diameter, 150m altitude, and 0.005km3 volume. Small protrusions, 10-50cm long, which are numerous on pillows appear to be the youngest regions, were sampled using the pincers on the hydraulic arms of Isis, and returned to the surface. On the surface, any glass crust on the pillow protrusions was chiselled off using clean tools and double bagged in polythene. In the laboratory a portion of the glass was crushed in a jewellers roller mill and sieved using stainless steel sieves to obtain a sufficient amount of the fraction 0.125-0.250mm for hand picking, using a binocular microscope with the glass submerged in a mix of water and iso-propyl alcohol. The samples were subsequently leached using the procedure of Standish & Sims2. Samples were spiked with a mixed 229Th-236U spike and the U, Th and Ra fractions were separated and purified using standard chemistry methods. U and Th isotope ratios were determined using a Nu Instruments MC-ICPMS and Ra isotope ratios were determined using a MAT-262-RPQII TIMS instrument. The U-series data were evaluated using a MathCad program based on published4,5,6 equations. The data can be successfully modelled by assuming the accepted mantle upwelling rate for the region of 11mm.y-1. The U-Th characteristics are mostly derived during porous flow magma upwelling in the garnet stability zone, ranging to a depth of 60km with incipient melting starting at 70km. Above 60km depth the melt fraction will be >3% and the mantle mineralogy devoid of phases that fractionate U-Th significantly. Moreover, at melt fractions >3%, channel flow will be dominant and magma will transit to eruption on time-scales that are short enough to retain the U-Th characteristics from the garnet zone. The rheology of the deep mantle is such that melt generation should be in steady state and U-Th characteristics should be constant. On that assumption, measured differences in collected samples can be used to calculate model ages relative to the youngest sample, thus allowing the construction of a relative eruption timescale. However, significant fractional crystallisation is taking place in the oceanic crust, as testified by the frequent presence of plagioclase crystals up to mm-size in the glass samples. A magma chamber on a scale larger than the magma channels is not required and we aim to assess the rate of plagioclase crystal growth using a 226Ra chronometer. This chronometer requires the assumption that Ba-Ra fractionation is constant and can then also be used to calculate a relative model age timescale, provided that not all samples are >8000 y old, which we consider unlikely. 1Searle, RC et al, EPSL in press, 2010 2Standish, JJ & Sims, KWW. Nature Geoscience V3, 2010 3Murton, BJ et al, in prep, 2010 4Williams, RW and Gill, JB, GCA 53, 1989 5Spiegelman, M and Elliott, T, EPSL 118, 1993 6Richardson, C and McKenzie, D, EPSL 128, 1994

  12. Behaviour of nuclides and U-series disequilibrium in clayey sediments: application to the Late Jurassic record from the eastern Paris basin

    NASA Astrophysics Data System (ADS)

    Casanova, J.; Ngrel, Ph.; Innocent, C.; Brulhet, J.

    2003-04-01

    We present a record of U-series disequilibrium covering the Callovo-Oxfordian-Thitonian times of the Late Jurassic carbonated platform from the eastern part of the Paris basin. The Callovo-Oxfordian clayey layer is the potential host rock for reconnaissance work carried out by Andra (e.g., Agence Nationale de Gestion des Dchets Radioactifs) in eastern France, the objective of which is the designing and building of an underground research laboratory to study the aptitude of the clay-marl Callovo-Oxfordian layer for the storage of radioactive wastes. We analyse U and Th trace elements on both the labile fraction (extracted by cold HCl) and the total bulk sediments. The Th contents are extremely low in the Oxfordian shelf reef carbonates (<10 ppb) with respect to the Kimmeridgian-Tithonian clayey marls and the Callovian-Oxfordian argilites (up to 10 ppm). In contrast, the uranium contents are much more homogenous (1 ppm 0.8) along the section. With respect to bulk concentrations, the nuclide contents in the labile component are particularly low in the Callovian-Oxfordian argilites. This behaviour suggests that given the extremely low permeability of the rock, any groundwater circulation of solutes could only have taken place by diffusion - a very slow mechanism that favours water-rock interactions. For U-series analyses (measured by alpha-spectrometry), a total of 43 bulk-rock samples were preferentially microdrilled from the fine-grained lithologies, although the heterogeneity of carbonate facies within sections necessitated occasional sampling of coarser grained lithologies. Within the carbonate-rich part (Oxfordian to Tithonian) of the section, the 234U/238U ratios slightly fluctuate from secular equilibrium and are interpreted as preferential 234U-solution processes related to groundwater circulation. Preferential removal of 234U in this zone is also indicated by some 230Th/234U activity ratios higher than unity. In contrast, most of the samples from the Callovian-Oxfordian argilites plot on or close to the secular equilibrium line. The observed isotopic disequilibriums from samples taken on either side of the interface between the clay formation and the carbonated country rock, are mainly related to a 234U deficiency relative to 230Th and correspond to bulk U-solution.

  13. U-Th-Ra-Pa Disequilibria in the Kasuga Seamounts: recent "sediment" flux melting in the Mariana rear arc

    NASA Astrophysics Data System (ADS)

    Gill, J.; Holden, P.

    2002-12-01

    Mariana volcanic front lavas define a U-Th isotope mixing line with an apparent age of 30 Ka between U-enriched "basalt fluid"-dominated Guguan and "sediment melt"-dominated Uracas in 238U-230Th equilibrium (Elliott et al., 1997). However, new results for basalts collected by dredging and diving on the shoshonitic Kasuga Seamounts, 10-20 km behind the VF, require re-interpretation of both Mariana components. Kasuga basalts are the local "sediment" extreme, reaching La/Sm = 5, Th/Nb=0.75, and eNd=3 in the most K-rich samples. Despite this extremity, their U-Th disequilibria lie along the same mixing line as for the VF, but extend to 20 percent 230Th-enrichment and (230Th)/(232Th) lower than at the intersection with the equiline. This indicates deeper melting than at the VF, and that the source's Th/U ratio was higher than the intersection. (226Ra)/(230Th) ratios extend to 3.5 even though samples have unknown eruption ages and Ba/Th is only 100, much lower than at the VF. (231Pa)/(235U) is mostly 1.7, higher than at the VF. (231Pa)/(230Th) correlates positively with excess U, consistent with recent flux melting. However, the mantle being melted is more fertile than at the VF, and the flux is more "sedimentary" apart from its disequilibria. Disequilibria in the highest-K Kasuga are most like Kick-em-Jenny, the most sediment-rich part of the Antilles.

  14. The tetranucleotide repeat polymorphism C2_4_4: population data and linkage disequilibria with HLA class I.

    PubMed

    Stadlbacher, Simone; Dauber, Eva-Maria; Wenda, Sabine; Glock, Barbara; Hafner, Maria; Krmczi, Gnther F; Mayr, Wolfgang R

    2003-01-01

    The tetranucleotide repeat locus C2_4_4 situated in the HLA class I region (6p21.3) and the HLA-ABC specificities were investigated in an Austrian population sample of 240 unrelated Caucasoid individuals. The analysis of the linkage disequilibrium between C2_4_4 and HLA class I showed several significant values, especially when factors coded for by so-called "superhaplotypes" were considered; such linkage disequilibria are of importance for the practical use of HLA coded short tandem repeats. PMID:12675271

  15. U-series constraints on the genesis of high-Mg andesites at White Island, new Zealand

    NASA Astrophysics Data System (ADS)

    Turner, S.; Zarah, H.; Schaefer, B.; George, R.; Berlo, K.; Cunningham, H.; Price, R.; Gamble, J.

    2006-12-01

    White Island, which lies off shore of New Zealand in the southern part of the Tonga-Kermadec island arc, has been erupting unusually primitive, high Mg andesites since 1977 which afford a unique opportunity to assess slab melting models. They are Fo80-93 olivine-saturated rocks which have MgO contents up to 10 percent (Mg# = 65-71) with SiO2 of 56-58 and contained 1.4-4.4 H2O. They have incompatible trace element characteristics that are typical of arc rocks and flat rare earth element patterns. 143Nd/144Nd and 176Hf/177Hf ratios of 0.51282-0.51266 and 0.28301-0.28298, respectively, are consistent with subducted sediment addition and there is no clear correlation of either isotope ratio with MgO. The rocks have modest (3-10 percent) 238U excesses at low (230Th/232Th) ratios (0.697 to 0.722). 226Ra-230Th disequilibria is also restricted but, unusually, includes both 226Ra excesses and deficits with (226Ra/230Th) = 0.93-1.07 and samples analysed for 210Pb have age corrected (210Pb/226Ra)o = 1.12-1.55. Sr/Y and Tb/Yb ratios are both low and relatively invariant at 8 and 0.3 respectively and along with the 238U-230Th disequilibria preclude an origin in which residual garnet was involved. The occurrence of 226Ra deficits and the preservation of a negative correlation between (226Ra/230Th) and (230Th/238U) require the presence of residual amphibole during partial melting followed by rapid magma ascent. This limits the amount of possible melt wall rock interaction which might reduce source-derived Tb/Yb ratios. The White Island high Mg andesites did not form by partial melting of eclogite in the subducting Pacific plate but do require a source containing residual amphibole which may be responsible for the elevated SiO2 of the rocks. Their primitive, olivine-saturated compositions suggest that the source was peridotitic rather than an amphibolitic underplate. The stability of amphibole may reflect the transition from oceanic to continental lithosphere and a cooler mantle wedge.

  16. U-series ages of solitary corals from the California coast by mass spectrometry

    USGS Publications Warehouse

    Stein, Martin; Wasserburg, G.J.; Lajoie, K.R.; Chen, J.-H.

    1991-01-01

    The purpose of this study is to evaluate the feasibility of dating fossil solitary corals from Pleistocene marine strandlines outside tropical latitudes using the recently developed high sensitivity, high-precision U-series technique based on thermal-ionization mass-spectrometry (TIMS). The TIMS technique is much more efficient than conventional a spectrometry and, as a result, multiple samples of an individual coral skeleton, or different specimens from the same bed can be analyzed. Detached and well-rounded fossil specimens of the solitary coral Balanophyllia elegans were collected from relict littoral deposits on emergent marine terraces along the California coast at Cayucos terrace (elevation 8 m, previously dated at 124 and 117 Ky by ?? counting), Shell Beach terrace (elevation about 25 m, previously undated), Nestor terrace, San Diego (elevation 23 m, previously dated at 131 to 109 Ky ), Bird Rock terrace, San Diego ( elevation 8 m, previously dated at 81 Ky ). Attached living specimens were collected from the intertidal zone on the modern terrace at Moss Beach. Concentrations of 232Th in both living and fossil specimens are much higher than in reef-building corals (12 to 624 pmol/g vs. 0.1 to 1.6 pmol/g, respectively). However, because 230Th/232Th in Balanophyllia elegans are very low (2.22 ?? 10-3 to 4.33 ?? 10-4), the high 232Th concentrations have negligible effect on the 230Th-234U dates. The high 232Th concentration in the living specimen (33.1 pmol/g) indicates that a significant amount of 232Th is incorporated in the aragonitic skeleton during growth, or attached to clay-sized silicates trapped in the skeletal material. The calculated initial 234U activities in the fossil specimens of Balanophyllia elegans are higher than the 234U activity in modern seawater or in the modern specimen. The higher initial activities could possibly reflect the influx of 234U-enriched continental water into Pleistocene coastal waters, or it could reflect minor diagenetic alteration, a persistent and fundamental problem in dating all corals. Samples from a compound specimen from the Cayucos terrace were subjected to different preparation procedures. Samples prepared by a standard acid washing procedure yielded 230Th-234U ages of 125, 123, and 122 Ky, whereas samples prepared by an abbreviated procedure without acid washing yield significantly lower ages of 113 and 112 Ky. Two other specimens from the same bed yielded 230Th-234U ages of 118 and 115 Ky. Also, two specimens from a stratigraphically higher bed yielded ages of 120 and 117 Ky, and three specimens from a lower bed yield ages of 115, 113, and 101 Ky. Nine of the twelve ages of the treated samples from the Cayucos terrace range from 125 to 113 Ky. However, the ages do not follow the stratigraphie order. Two possible interpretations are ( 1 ) the age of the terrace deposit is 125 Ky and all younger ages reflect variable diagenetic alteration or (2) the age of the terrace is 125 to 113 Ky and the ages reflect sediment reworking over a period of 12 Ky. Three specimens from a single bed on the Shell Beach terrace yield ages of 126, 122, and 121 Ky, similar to the older ages from Cayucos. The ages of solitary corals from the Cayucos and Shell Beach terraces are similar to ages of reef-building corals from terraces at numerous tropical localities. These are correlated with the last interglacial sea-level highstand, which probably stood 2 to 10 m above present sea level. The youngest ages and present elevations of the Cayucos and Shell Beach terraces yield tectonic uplift rates of 0.01 and 0.15 m/Ky, respectively, assuming the original elevation of each terrace was 7 m. Four specimens from the basal gravel on the Nestor terrace yielded ages of 145, 143, 137, and 133 Ky. The three oldest ages, however, are older than that associated with the last interglacial. The possible explanations for these older ages are ( 1 ) diagenic alteration or ( 2 ) the Nestor terrace deposits reflect in s

  17. Relatively Recent Volcanism on Oahu, Hawaii: New U-series and Paleomagnetic Age Constraints on the Hanauma Bay Eruption

    NASA Astrophysics Data System (ADS)

    Rubin, K. H.; Jurado-Chichay, Z.; Urrutia-Fucugauchi, J.

    2002-12-01

    The Koko Rift Zone (KRZ), eastern Oahu, is generally regarded as among the youngest volcanic features on the island. Previous workers have suggested that the 9 or 10 vents of this rift erupted near-simultaneously. However, K-Ar data in the literature (32-39 ka vs 320 ka) provide only general guidance on the youthfulness of these eruptions. We present new age constraints on KRZ volcanism using deposits of the phreatomagmatic eruption that produced Hanauma Bay (a popular snorkeling spot) and spatially associated lava flows. Numerous continuous basaltic ash units within the walls of Hanauma crater contain lithic fragments of well-preserved coral reef, beach rock, and marine mollusks, indicating that the eruption occurred in a near shore environment. 238U-234U-230Th dating of coral clasts in the deposit demonstrates that the eruption breached reef of MIS stage 7 age (200 +/- 30 ka), thereby ruling out the K-Ar age of 320 ka. U-series nuclides in "normal" MIS 7 coral lithics are indistinguishable from those in the island encircling Waianae Reef of the same age. However, U-series components in some originally aragonitic coral clasts were offset during the eruption when the rims recrystallized to calcite. 87Sr/86Sr, 234U/238U and Sr and U concentration indicate chemical mixing with host basaltic ash during this event, from which potential ages of the eruption can be constructed using isochron methods. More modeling of the data remains to be done but our preliminary estimate places the eruption at less than 100 ka. This result is consistent with new data on paleointensity and paleomagnetic secular variation within the lava flows exposed in or around the crater. This U-series dating approach should prove useful for eruptions in other locales where carbonate bioclast lithics are present in the deposits.

  18. Magmas, Mushes and Mobility: Thermal Histories of Magma Reservoirs from Combined U-Series and Diffusion Ages

    NASA Astrophysics Data System (ADS)

    Cooper, K. M.; Rubin, A. E.; Schrecengost, K.; Kent, A. J.; Huber, C.

    2014-12-01

    The thermal conditions of magma storage control many aspects of the dynamics of a magma reservoir system. For example, the temperature of magma storage directly relates to the crystallinity, and magmas stored at relatively low temperatures in a crystal mush (more than 40-50% crystalline) must be remobilized (e.g., by heating) before they can be erupted. A better understanding of the duration of magma storage at largely-liquid vs. largely-solid conditions is thus critical to understanding crustal magmatic processes such as magma mixing and for quantifying the hazard potential of a given volcano. Although mineral thermometry reflects the conditions of crystal growth or equilibration, these may not correspond to the thermal conditions of crystal storage. The duration of crystal storage at high temperatures can be quantified by comparing U-series crystal ages with the time scales over which disequilibrium trace-element profiles in the same crystals would be erased by diffusion. In the case of Mount Hood, OR, such a comparison for the two most recent eruptions shows that <12% of the total lifetime of plagioclase crystals (minimum 21 kyr) was spent at temperatures high enough that the magma would be easily mobilized. Partial data sets for other systems suggest such behavior is common, although the diffusion and U-series ages in these cases are from different samples and may not be directly comparable. We will present preliminary data combining U-series dating and diffusion timescales on the same samples for other volcanic systems (e.g., Lassen Volcanic Center, Mount St. Helens, Okataina Volcanic Center, New Zealand). Combining these data with numerical models offers additional insights into the controls on the conditions of storage. In addition, extension of this approach to combining U-Th ages with time scales of Li diffusion in zircon offers a promising new method to quantify thermal histories of silicic reservoir systems.

  19. Preliminary U-series disequilibrium and thermoluminescence ages of surficial deposits and paleosols associated with Quaternary fault, Eastern Yucca Mountain

    SciTech Connect

    Paces, J.B.; Menges, C.M.; Bush, C.A.; Futa, K.; Millard, H.T.; Maat, P.B.; Whitney, J.W.; Widmann, B.; Wesling, J.R.

    1994-12-31

    Geochronological control is an essential component of paleoseismic evaluation of faults in the Yucca Mountain region. New U-series disequilibrium and thermoluminescence age estimates for pedogenic deposits that bracket surface-rupture events are presented from four sites exposing the Paintbrush Canyon, Bow Ridge and Stagecoach Road faults. Ages show an internal consistency with stratigraphic relationships as well as an overall concordancy between the two independent geochronometers. Age estimates are therefore interpreted to date depositional events or episodes of pedogenic carbonate mobility that can be used to establish a paleoseismic fault chronology. Ultimately, this type of chronological information will be used to evaluate seismic hazards at Yucca Mountain.

  20. U-Series dates for stalagmitic flowstone E (Riss/Wrm interglaciation) at Grotte du Lazaret, Nice, France

    USGS Publications Warehouse

    Falgueres, Christophe; de Lumley, Henry; Bischoff, James L.

    1992-01-01

    Several samples of stalagmitic flowstone (Ensemble E) at Grotte du Lazaret (Nice, France) were dated by U-series isotopes. The results show that this speleothem began to grow about 130,000 yr B.P. and continued to about 70,000 yr B.P., coinciding almost exactly with the last interglaciation (isotope stage 5). Even though Ensemble E is not in direct stratigraphic relation with the cave deposits, this study shows that the Acheulian artifacts industry and fauna within Lazaret are older than the Riss/Wurm interglaciation.

  1. Internal [sup 238]U-series systematics of pumice from the November 13, 1985, eruption of Nevado de Ruiz, Colombia

    SciTech Connect

    Schaefer, S.J.; Williams, S.N. ); Sturchio, N.C. ); Murrell, M.T. )

    1993-03-01

    High-precision mass spectrometer and alpha scintillation measurements of [sup 238]U-series nuclides were obtained for whole-rock pumice and constituent mineral and glass separates to help interpret the timing and nature of magmatic processes that led up to the 1985 eruption of Nevado de Ruiz volcano. Internal isochron diagrams for [sup 226]Ra/Ba vs. [sup 230]Th/Ba and [sup 230]Th/[sup 232]Th vs. [sup 238]U/[sup 232]Th show that data define linear arrays, indicating an average crystallization age of 6.1 [+-] 0.5 ka (Ra-Th isochron) and 7 [+-] 6 ka (Th-U isochron). Stratigraphic, petrographic geochemical, repose time, and eruption volume data for the Holocene eruptive sequence of Nevado del Ruiz indicate that significant changes occurred in the subvolcanic magma chamber between eruptions R9 ([approx]8.6 ka) and R8 ([approx]3.0 ka). This coincides with the average crystallization age derived from the U-series data and may represent the injection of a new batch (or batches) of mantle-derived magma into the subvolcanic magma chamber. 26 refs., 4 figs., 2 tabs.

  2. Regolith production and transport in the Susquehanna Shale Hills Critical Zone Observatory, Part 1: Insights from U-series isotopes

    NASA Astrophysics Data System (ADS)

    Ma, Lin; Chabaux, Francois; West, Nikki; Kirby, Eric; Jin, Lixin; Brantley, Susan

    2013-06-01

    investigate the timescales of regolith formation on hillslopes with contrasting topographic aspect, we measured U-series isotopes in regolith profiles from two hillslopes (north facing versus south facing) within the east-west trending Shale Hills catchment in Pennsylvania. This catchment is developed entirely on the Fe-rich, Silurian Rose Hill gray shale. Hillslopes exhibit a topographic asymmetry: The north-facing hillslope has an average slope gradient of ~20°, slightly steeper than the south-facing hillslope (~15°). The regolith samples display significant U-series disequilibrium resulting from shale weathering. Based on the U-series data, the rates of regolith production on the two ridgetops are indistinguishable (40 ± 22 versus 45 ± 12 m/Ma). However, when downslope positions are compared, the regolith profiles on the south-facing hillslope are characterized by faster regolith production rates (50 ± 15 to 52 ± 15 m/Ma) and shorter durations of chemical weathering (12 ± 3 to 16 ± 5 ka) than those on the north-facing hillslope (17 ± 14 to 18 ± 13 m/Ma and 39 ± 20 to 43 ± 20 ka). The south-facing hillslope is also characterized by faster chemical weathering rates inferred from major element chemistry, despite lower extents of chemical depletion. These results are consistent with the influence of aspect on regolith formation at Shale Hills; we hypothesize that aspect affects such variables as temperature, moisture content, and evapotranspiration in the regolith zone, causing faster chemical weathering and regolith formation rates on the south-facing side of the catchment. The difference in microclimate between these two hillslopes is inferred to have been especially significant during the periglacial period that occurred at Shale Hills at least ~15 ka before present. At that time, the erosion rates may also have been different from those observed today, perhaps denuding the south-facing hillslope of regolith but not quite stripping the north-facing hillslope. An analysis of hillslope evolution and response timescales with a linear mass transport model shows that the current landscape at Shale Hills is not in geomorphologic steady state (i.e., so-called dynamic equilibrium) but rather is likely still responding to the climate shift from the Holocene periglacial to the modern, temperate conditions.

  3. Combined ESR/U-series chronology of Acheulian hominid-bearing layers at Trinchera Galera site, Atapuerca, Spain.

    PubMed

    Falgures, Christophe; Bahain, Jean-Jacques; Bischoff, James L; Prez-Gonzlez, Alfredo; Ortega, Ana Isabel; Oll, Andreu; Quiles, Anita; Ghaleb, Bassam; Moreno, Davinia; Dolo, Jean-Michel; Shao, Qingfeng; Vallverd, Josep; Carbonell, Eudald; Bermdez de Castro, Jose Mara; Arsuaga, Juan Luis

    2013-08-01

    The Sierra de Atapuerca, northern Spain, is known from many prehistoric and palaeontological sites documenting human prehistory in Europe. Three major sites, Gran Dolina, Galera and Sima del Elefante, range in age from the oldest hominin of Western Europe dated to 1.1 to 1.3Ma (millions of years ago) at Sima del Elefante to c.a. 0.2Ma on the top of the Galera archaeological sequence. Recently, a chronology based on luminescence methods (Thermoluminescence [TL] and Infrared Stimulated Luminescence [IRSL]) applied to cave sediments was published for the Gran Dolina and Galera sites. The authors proposed for Galera an age of 450ka (thousands of years ago) for the units lower GIII and GII, suggesting that the human occupation there is younger than the hominid remains of Sima de los Huesos (>530ka) around 1km away. In this paper, we present new results obtained by combined Electron Spin Resonance/Uranium-series (ESR/U-series) dating on 20 herbivorous teeth from different levels at the Galera site. They are in agreement with the TL results for the upper part of the stratigraphic sequence (GIV and GIIIb), in the range of between 200 and 250ka. But for the GIIIa to GIIb levels, the TL ages become abruptly older by 200 ka while ESR ages remain relatively constant. Finally, the TL and ESR data agree in the lowest part of the section (GIIa); both fall in the range of around 350-450ka. Our results suggest a different interpretation for the GII, GIII and GIV units of Galera and the upper part of Gran Dolina (TD10 and TD11) than obtained by TL. The ESR/U-series results are supported by a Bayesian analysis, which allows a better integration between stratigraphic information and radiometric data. PMID:23830175

  4. Linkage disequilibria between mtDNA haplotypes and chromosomal arrangements in a natural population of Drosophila subobscura.

    PubMed

    Oliver, P; Castro, J A; Picornell, A; Ramon, M M; Sol, E; Balany, J; Serra, L; Latorre, A; Moya, A

    2002-08-01

    The association between mtDNA haplotypes and chromosomal arrangements in a natural population of Drosophila subobscura from Calvia (Balearic Islands, Spain) was studied in order to search for linkage disequilibria, in an attempt to explain the populational dynamics of the mtDNA haplotypes of this species in nature. The presence of Wolbachia was not detected. Two main haplotypes (I and II) were found, as well as a series of less common ones. The Tajima D-test seemed to indicate some kind of seasonal population bottleneck. An analysis of linkage disequilibrium and factorial analysis of correspondences detected an association between haplotype I and the J(ST) inversion and haplotype II and the J(1) inversion. PMID:12136416

  5. Coupling data from U-series and 10Be CRN to evaluate soil steady-state in the Betic Cordillera

    NASA Astrophysics Data System (ADS)

    Schoonejans, Jerome; Vanacker, Veerle; Opfergelt, Sophie; Granet, Mathieu; Chabaux, Franois

    2015-04-01

    The regolith mantel is produced by weathering of bedrock through physical and biochemical processes. At the same time, the upper part of the regolith is eroded by gravity mass movements, water and wind erosion. Feedback's between production and erosion of soil material are important for soil development, and are essential to reach long-term steady-state in soil chemical and physical properties. Nowadays, long-term denudation rates of regolith can be quantified by using in-situ cosmogenic nuclides (CRN). If the soil thickness remains constant over sufficiently long time, soil production rates can be determined. However, the a priori assumption of long-term steady-state can be questionable in highly dynamic environments. In this study, we present analytical data from two independent isotopic techniques, in-situ cosmogenic nuclides and Uranium series disequilibrium. The disequilibrium of Uranium isotopes (238U, 234U, 230Th, 226Ra) is an alternative method that allows assessing soil formation rates through isotopic analysis of weathering products. Nine soil profiles were sampled in three different mountain ranges of the Betic Cordillera (SE Spain): Sierra Estancias, Filabres, Cabrera. All soils overly fractured mica schist and are very thin (< 60cm). In each soil profile, we sampled 4 to 6 depth slices in the soil profile, the soil-bedrock interface and (weathered) bedrock. Three of the nine soil profiles were sampled for U-series isotope measurements at EOST (University of Strasbourg). The surface denudation rates (CRN) are about the same in the Sierra Estancias and Filabres (26 10 mm/ky) and increase up to 103 47 mm/ky in the Sierra Cabrera. The spatial variation in soil denudation rates is in agreement with the variation in catchment-wide denudation rates presented by Bellin et al. (2014) which present the highest rates in the Sierra Cabrera (104-246mm/kyr). Moreover it roughly coincides with the pattern of long-term exhumation of the Betic Cordillera. Results from first simulations of the U-series disequilibrium model rather suggest that soil production rates are of the same order of magnitude in the Sierra Estancias and Cabrera. In the Sierra Filabres, the U-series disequilibrium in the depth profile do not respect the hypotheses of the model therefore no rates of soil production could be constrain for this profile. Thanks to the coupling of the two isotopic datasets the long term soil development will be explored in two profiles. This study highlights that comparison and combination of analytical techniques is useful to further unravel the mechanisms of chemical and physical weathering in such dynamic environments. Bellin, N., Vanacker, V., and Kubik, P. W., 2014, Denudation rates and tectonic geomorphology of the Spanish Betic Cordillera: Earth and Planetary Science Letters, v. 390, p. 19-30.

  6. U-Th-Ra in Amazon rivers: New insights on U-series fractionation during chemical weathering

    NASA Astrophysics Data System (ADS)

    Dosseto, A.; Bourdon, B.; Gaillardet, J.; Allegre, C. J.

    2002-12-01

    Seawater ({ 234} U/{ 238} U) has been proposed as a proxy for understanding past continental weathering conditions. Thus, it is crucial to constrain the parameters that control U-series fractionation during present day weathering in order to understand what they have recorded in the past. Additionally, U-series provide useful constraints for understanding chemical weathering as a function of environmental variables. We have analyzed { 238} U-{ 234} U-{ 230} Th-{ 226} Ra compositions in the dissolved phase (< 0.2?m) of Amazon river and major tributaries. Two groups can be distinguished within Amazon tributaries: river draining mainly the Andes and the Brazilian shield; and rivers dominated by dissolved organic material. The latter are characterized by the absence of { 238} U-{ 234} U fractionation and very high Th contents (> 80ng/l) whereas the former display { 234} U excess over { 238} U and lower Th contents (< 30ng/l). High Th concentrations for organic-rich waters are consistent with a previous study, which revealed the existence of strong complexes between Th and humic acids (Viers et al., 1997). The lack of { 234} U-{ 238} U disequilibrium in organic-rich waters suggests that dissolved organic matter may play a role on { 234} U-{ 238} U fractionation. However, as ({ 234} U/{ 238} U) ratio of the Amazon mainstream is dominated by Solim\\~{ o}es and Madeira compositions, dissolved organic matter is believed to have minor consequences on the ({ 234} U/{ 238} U) input to the ocean. { 232} Th/{ 238} U of the source material based on ({ 230} Th/{ 232} Th) ratios range, for some rivers, between 5.5 and 8.7, which is higher than the estimated value based on { 208} Pb-{ 206} Pb systematics in Amazon rivers (ca. 3.8; All\\`{ e}gre et al., 1996). This may be the result of past U-removal during previous weathering events over time-scales longer than the half-life of thorium-230 (75 ka). References: Viers J. et al. (1997) Chem. Geol., vol. 140, pp. 181-206 All\\`{ e}gre C. J. et al. (1996) Chem. Geol., vol. 131, pp. 93-112

  7. Uranium-series disequilibria in Vanuatu arc volcanic rocks: constraints on pre-eruptive processes in contrasting volcanic systems

    NASA Astrophysics Data System (ADS)

    Handley, H. K.; Turner, S.; Reagan, M. K.; Girard, G.; Cronin, S. J.; Firth, C.

    2011-12-01

    Recent and present volcanism in the Vanuatu arc (South West Pacific Ocean) occurs at a variety of volcano types that exhibit a wide range of eruptive behaviour: from post-caldera lava-lake activity and lava flows at shield volcanoes (Ambrym), moderately explosive sub-plinian events and associated pyroclastic-flows and lava flows at stratovolcanoes (Lopevi), to persistent strombolian and vulcanian-style eruptions at scoria cones (Yasur). This precludes a generic model of magmatic and eruptive behaviour for the Vantuatu arc volcanoes and necessitates a detailed study of each system. Uranium-series disequilibria in volcanic rocks offer unique insights into pre-eruptive magmatic systems over process-relevant timescales e.g., 238U-230Th (380Ka), 230Th-226Ra (8Ka) and 226Ra-210Pb (100a). The short half-life of 210Pb (t1/2 = 22.6 years) and the volatile nature of the intermediate isotope, 222Rn, (intermediate between the 226Ra parent and 210Pb daughter) provide valuable information on magma transport, evolution and degassing over a timescale more pertinent to the processes leading up to volcanic eruptions. We present new Uranium-series isotope data (U-Th-Ra-210Pb) for young (< 100 years old) volcanic samples from Ambrym, Lopevi and Yasur volcanoes to investigate the timescales of magmatic evolution and degassing in the contrasting volcanic systems. 210Pb deficits ((210Pb/226Ra)0 < 1) in Ambrym and Yasur volcanic rocks suggest effective open-system magmatic degassing of 222Rn, consistent with the persistent lava-lakes/exposed magma and significant gas emissions observed at both volcanoes. Lopevi, on the other hand, largely displays excess 210Pb ((210Pb/226Ra)0 > 1) suggesting that 222Rn gas accumulation and fluxing preceding and/or during eruption (on a decadal timescale) is responsible for the more explosive-style of eruption witnessed at this volcano. Significant accumulation of recently crystallised plagioclase phenocrysts can also create 210Pb excesses in volcanic rocks, however, this process is not supported by the petrographic and geochemical data. In summary 210Pb-226Ra disequilibria in Vanuatu volcanic rocks reveal a strong link between pre-eruptive magma degassing systematics and the resultant style of volcanic activity.

  8. Soil formation rates determined from Uranium-series isotope disequilibria in soil profiles from the southeastern Australian highlands

    NASA Astrophysics Data System (ADS)

    Suresh, P. O.; Dosseto, A.; Hesse, P. P.; Handley, H. K.

    2013-10-01

    The sustainability of soil resources is determined by the balance between the rates of production and removal of soils. Samples from four weathering profiles at Frogs Hollow in the upper catchment area of the Murrumbidgee River (southeastern Australia) were analyzed for their uranium-series (U-series) isotopic composition to estimate soil production rates. Sequential leaching was conducted on sample aliquots to assess how U-series nuclides are distributed between primary and secondary minerals. Soil is increasingly weathered from bottom to top which is evident from the decrease in (234U/238U) ratios and increase in relative quartz content with decreasing soil depth. One soil profile shows little variation in mineralogy and U-series geochemistry with depth, explained by the occurrence of already extensively weathered saprolite, so that further weathering has minimal effect on mineralogy and geochemistry. Al2O3 is mobilized from these soils, and hence a silicon-based weathering index treating Al2O3 as mobile is introduced, which increases with decreasing soil depth, in all profiles. Leached and unleached aliquots show similar mineralogy with slight variation in relative concentrations, whereas the elemental and isotopic composition of uranium and thorium show notable differences between leached and unleached samples. Unleached samples show systematic variations in uranium-series isotopic compositions with depth compared to leached samples. This is most likely explained by the mobilization of U and Th from the samples during leaching. Soil residence times are calculated by modeling U-series activity ratios for each profile separately. Inferred timescales vary up to 30 kyr for unleached aliquots from profile F1 to up to 12 kyr for both leached and unleached aliquots from profile F2. Muscovite content shows a linear relationship with U-series derived soil residence times. This relationship provides an alternative method to estimate residence timescales for profiles with significant U-series data scatter. Using this alternative approach, inferred soil residence times up to 33 kyr for leached samples of profile F1 and up to 34 kyr for leached samples of profile F3 were determined. A linear relationship between soil residence times and WIS (Si-based Weathering Index) exists and is used to estimate soil residence times for profile F3 (up to 28 kyr) and F4 (up to 37 kyr). The linear relationship between soil depth and calculated residence time allows determination of soil production rates, which range from 10 to 24 mm/kyr and are comparable to the rates determined previously using cosmogenic isotopes at the same site (Heimsath et al., 2001b). This implies that at this site, on the highland plateau of southeastern Australia, soil thickness has reached steady-state, possibly as a result of stable tectonic conditions but despite variable climatic conditions over the timescale of soil development. Soil-mantled landscapes are the geomorphic expression of this balance between soil production and denudation, and our results show that in tectonically quiescent regions, this landscape can be achieved in less than 30 kyr.

  9. TIMS U-series dating and stable isotopes of the last interglacial event in Papua New Guinea

    SciTech Connect

    Stein, M.; Wasserburg, G.J.; Chen, J.H. ); Aharon, P. ); Zhu, Z.R.; Chappell, J. ); Bloom, A. )

    1993-06-01

    The extensive flight of uplifted reef terraces which occurs along the Vitiaz strait on the northern flank of the Huon Peninsula in PNG (Papua New Guinea) contains a particularly good record of sea level changes in the last 250 ky. The Huon terraces were the target of an international expedition which took place in July--August 1988. In particular, the authors searched for suitable samples for U-series dating in a reef complex designated as VII, which is correlated with the last interglacial episode and high sea level stand. This complex is composed of a barrier reef (VIIb), a lagoon, and a fringing reef (VIIa). Twelve corals from these terraces and two corals from the older reef complex VIII were selected for analysis. The petrography, oxygen and carbon isotope compositions, and magnesium and strontium concentrations were determined along with the concentrations and isotopic compositions of uranium and thorium. The simplest model for sea level height for terrace VII is a continuous rise between 134 and 118 ky. Alternatively, there may have been two periods of rapid sea level rise. In contrast, in the Bahamas, there is evidence that sea level remained rather constant over the time interval 132 to 120 ky. The absence of ages between 132 and 120 ky in PNG could be the result of changes in the local tectonic uplift rates during that time, or erosion that disrupted the continuous record. In any event, the authors find no basis for accepting a single brief time for the age of the last interglacial and applying this age as a precise chronometer for worldwide correlation, or as a test of climatic models. The older ages reported here precede the Milankovitch solar insolation peak at 128 ky, and the younger ages are [approximately]10 ky after this peak. If the present high-precision data are correct, then it will be necessary to reassess the validity of the Milankovitch theory of climatic changes. 76 refs., 6 figs., 6 tabs.

  10. Crystallization history of rhyolites at Long Valley, California, inferred from combined U-series and Rb-Sr isotope systematics

    NASA Astrophysics Data System (ADS)

    Heumann, Arnd; Davies, Gareth R.; Elliott, Tim

    2002-05-01

    In this study, we present 87Rb/ 86Sr and 230Th/ 238U isotope analyses of glasses and phenocrysts from postcaldera rhyolites erupted between 150 to 100 ka from the Long Valley magmatic system. Both isotope systems indicate complex magma evolution with preeruptive mineral crystallization and magma fractionation, followed by extended storage in a silicic magma reservoir. Glass analyses yield a Rb-Sr isochron of 257 39 ka, which can be explained by a feldspar-fractionation event 150 ky before eruption. Individual feldspar-glass pairs confirm this age result. A mineral 230Th- 238U isochron in a low-silica rhyolite from the Deer Mountain Dome defines an age of 236 1 ka, but the glass and whole rock do not lie on the isochron. U-Th fractionation of the rocks is controlled by the accessory minerals zircon and probably allanite, which crystallized at 250 3 ka and 187 9 ka, respectively. All major mineral phases contain accessory mineral phases; therefore, the mineral isochron represents a mixture of zircon and allanite populations. A precision of 1 ka for the mixing array implies that the minor phases must have crystallized within this timescale. Longer periods of crystal growth would cause the mixing array to be less well defined. U-series data from other low- and high-silica rhyolites indicate younger accessory mineral crystallization events at 200 and 140 ka, probably related to the thermal evolution of the magma reservoir. These crystallization events are, however, only documented by the accessory minerals and had no further influence on bulk magma compositions. We interpret the indistinguishable age results from both isotope systems (250 ka) to record the fractionation of small magma batches by filter pressing from a much larger underlying magma volume, followed by physical isolation and extended storage at the top of the magma reservoir for up to 150 ky.

  11. Rapid response of climatic conditions during the last glacial: evidence from U-series dated Irish speleothems

    NASA Astrophysics Data System (ADS)

    Fankhauser, A.; McDermott, F.; Fleitmann, D.; Hoffmann, D. L.

    2012-04-01

    Rapid climate change events (Dansgaard-Oeschger and Heinrich events) during the last glacial have been well documented in the Greenland ice cores (e.g. NGRIP), but their impact at lower latitudes is still not fully understood. In Ireland, few climate records older than the Last Glacial Maximum (LGM) exist due to extensive glacial reworking. Exceptions are cave deposits in an environment protected from extensive glacial erosion. Speleothem deposition requires the presence of liquid water implying cave air temperatures above 0C. As air temperature in shallow caves (<30m depth) is similar to the mean annual air temperature (MAAT) at the surface; speleothem deposition can only occur in the absence of permafrost or glaciation. In this study, intervals of speleothems deposition in Crag cave, South West Ireland have been determined by U-series-dating to constrain the timing of ice- and permafrost-free conditions prior to the LGM. Here we present evidence for episodic speleothem deposition between the Holocene and the last interglacial. Ninety eight U-Th dates indicate phases of speleothem deposition, interrupted by visible hiatuses e.g. at 131.5 0.6; 104.8 0.2; 83.9 0.3; 71.7 0.2; 65.2 0.2; 58.9 0.3; 47.1 0.1; 43.5 0.2; 40.0 0.1; 38.0 0.1; 32.1 0.1; 28.8 0.1; 27.8 0.1; 23.3 0.1; 12.5 0.2; 11.6 0.1; 8.5 0.4 ka. These depositional intervals in Crag cave speleothems show an overall synchronicity with Dansgaard-Oeschger (D-O) events recorded in NGRIP. Furthermore, Heinrich events 2, 3, 4, 5 and 6 are characterised by non-deposition. Measured ?18O values in Crag cave speleothems deposited during Marine Isotope Stage (MIS) 5a are similar to the mean value for Holocene speleothems (?18O = -3.26 VPDB). A trend to higher ?18O values during the glacial is interpreted to predominantly reflect changes in the ocean source region (ice volume effect). Observed ?13C values down to -10 (VPDB) indicate the presence of C3 vegetation above the cave during warmer intervals such as the D-O events. Correlations between ?18O and ?13C in some samples suggest strong kinetic effects. This is particularly evident in calcite deposited prior to the onset of depositional hiatuses, interpreted to reflect gradually decreasing drip rates.

  12. Using U-series isotopes to quantify regolith formation and chemical weathering rates along a climosequence associated with the Susquehanna Shale Hills Critical Zone Observatory

    NASA Astrophysics Data System (ADS)

    Ma, L.; Chabaux, F. J.; Dere, A. L.; White, T.; Jin, L.; Brantley, S. L.

    2012-12-01

    Regolith formation and chemical weathering are important Critical Zone processes and are responsible for soil development. Despite their fundamental importance, we still lack effective tools to quantify these processes. U-series isotopes offer a powerful geochronometer to quantify regolith production rates and weathering duration. This is largely due to improvements in analytical methods and mathematical approaches made over the last decade in measuring U-series isotopes and interpreting their fractionation during chemical weathering. Here, we present a systematic study of U-series isotopes (238U, 234U and 230Th) in shale-derived soils from five small watersheds in the eastern USA to understand the rates of regolith formation as a function of climate. The selected watersheds in Pennsylvania, Virginia, Tennessee, Alabama, and Puerto Rico are part of the shale transect established as part of the Susquehanna Shale Hills Critical Zone Observatory. We first measured U-series isotopes in six regolith profiles from two planar hill-slopes (north vs. south) within the Shale Hills CZO in central PA to evaluate the role of aspect on regolith formation in the small watershed. All regolith samples display significant U-series disequilibrium. These U-series disequilibrium values are explained by two processes acting on U-series isotopes during weathering: a loss of 234U, 238U, and 230Th during water-rock interactions and a gain from circulating soil water and/or downslope particle transport. Regolith production rates and weathering durations were calculated with a U-series isotope mass balance model. On the southern (shaded) slope, regolith production rates decrease systematically with increasing soil thickness and distance from the ridge: from ~44.5 m/Myr at the ridge top to ~15.0 m/Myr at the valley floor. Durations of chemical weathering within these profiles range from 6.7 kyr to 44.7 kyr, increasing from the ridge to the valley floor. The regolith profiles on the northern (sun-facing) slope are characterized by faster regolith production rates (~40-52 m/Myr) and shorter durations of chemical weathering in the regolith zone (~12-16 kyr). These results reveal the important control of hill-slope aspect on the rate of regolith formation at Shale Hills: we hypothesize that aspect creates microclimates that in turn affect slope stability and erosion, and set different regolith residence times. The difference in microclimate is inferred to have been important before and during the periglacial period that occurred at Shale Hills ~15 ka. Our ongoing investigation of the four additional gray shale watersheds in VA, TN, AL, and PR provides information on shale weathering along a climosequence at a much larger continental scale. Only ridge top sites were selected to limit the aspect effect. This systematic study will enable us to quantitatively model regolith formation and landscape development on gray shales and to consider the effects of ongoing climate change.

  13. U-series dates on travertine deposits in the Great Artesian Basin as paleohydrogeology and neotectonic indicators

    NASA Astrophysics Data System (ADS)

    Priestley, S.; Karlstrom, K. E.; Crossey, L. J.; Love, A.; Polyak, V.; Asmerom, Y.; Embid, E.

    2010-12-01

    Travertine deposits of the western Great Artesian Basin (GAB) are associated with mound springs (many still active) and form calcium carbonate precipitates due to CO2 degassing as the highly carbonated groundwaters emerge along faults. They collectively, provide a record that can be used to link the present hydrogeological system to the paleohydrogeology of the GAB. The GAB is a very large artesian sedimentary basin which contains groundwater that has evolved over hundreds of thousands to millions of years. Although the equipotential surface has declined since development of the aquifer, anthropogenic draw down is superimposed on less well understood transient effects due to paleoclimate cycles which requires better understanding of the flow paths and paleohydrologic fluctuations in the GAB. Travertines can provide proxy data to understand the relative magnitude and chronology of spring discharge through time, which will aid in the development of a transient conceptual groundwater model of the system. The travertine deposits also provide underutilized and sensitive gauges of neotectonics in Australia, generally thought of as one of the oldest, flattest, and least tectonically active of the continents, but one that is neotectonically active in the western GAB area. U-Series dates provide age constraints on travertine deposition. Travertines at Dalhousie Springs range from 687 228 ka to 163 7 ka. Travertines along the mound springs line range from 372 14 ka (Beresford extinct mound) to 0.12 0.001 ka (Sulfur spring). The dates indicate persistent deposition at discrete spring vents over at least 700 thousand years. Our hypothesis is that times of largest travertine accumulations (10 - 20 ka, 120 ka, 250 ka, and 350 - 400 ka) may have corresponded to wetter times. Stable isotope analyses of the dated travertines reveals that spring groups have different carbon isotope values that vary by 4 - 6 per mil in O, reflecting local spring chemistry and/or paleoclimate variations. These results demonstrate that the extensive travertine deposits can be used to develop a paleohydrogeology record at both 100 ka and 10 - 1 ka time scales for comparison with other paleoclimate proxies. Mound spring discharge is aligned along faults that parallel lithosopheric zones of weakness along the Tasman line and Torrens hinge zone, these separate the actively uplifting Flinders and Dennison Ranges from subsiding Lake Eyre region. An age of 372 14 ka from the elevated extinct Beresford mound indicates bedrock denudation rates of the Bulldog shale surface of 67 m/Ma that are likely driven by neotectonics. More comprehensive dating may show differential uplift depending on position relative to uplifting versus subsiding domains on either side of the mound springs line. Collectively, the lowest elevations in the Australian continent, the mound springs lineaments, and the resulting locations of the main discharge areas of the GAB are seen as a product of different interacting scales of active tectonism in central Australia.

  14. U-series and oxygen isotope chronology of the mid-Pleistocene Lake Amora (Dead Sea basin)

    NASA Astrophysics Data System (ADS)

    Torfstein, Adi; Haase-Schramm, Alexandra; Waldmann, Nicolas; Kolodny, Yehoshua; Stein, Mordechai

    2009-05-01

    This study establishes for the first time the chronology and limnological history of Lake Amora (Dead Sea basin, Israel), whose deposits (the Amora Formation) comprise one of the longest exposed lacustrine records of the Pleistocene time. The Amora Formation consists of sequences of laminated primary aragonite and silty-detritus, Ca-sulfate minerals, halite and clastic units. This sedimentary sequence was uplifted and tilted by the rising Sedom salt diapir, exposing 320 m of sediments on the eastern flanks of Mt. Sedom (the Arubotaim Cave (AC) section). The chronology of the AC section is based on U-disequilibrium dating ( 230Th- 234U and 234U- 238U ages) combined with floating ?18O stratigraphy and paleomagnetic constraints. The determination of the 230Th- 234U ages required significant corrections to account for detrital Th and U. These corrections were performed on individual samples and on suites of samples from several stratigraphic horizons. The most reliable corrected ages were used to construct an age-elevation model that was further tuned to the oxygen isotope record of east Mediterranean foraminifers (based on the long-term similarity between the sea and lake oxygen isotope archives). The combined U-series- ?18O age-elevation model indicates that the (exposed) Amora sequence was deposited between 740 and 70 ka, covering seven glacial-interglacial cycles (Marine Isotope Stages (MIS) 18 to 5). Taking the last glacial Lake Lisan and the Holocene Dead Sea lacustrine systems as analogs of the depositional-limnological environment of Lake Amora, the latter oscillated between wet (glacial) and more arid (interglacial) conditions, represented by sequences of primary evaporites (aragonite and gypsum that require enhanced supply of freshwater to the lakes) and clastic sediments, respectively. The lake evolved from a stage of rapid shifts between high and low-stand conditions during 740 to 550 ka to a sabkha-like environment that existed (at the AC site) between 550 and 420 ka. This stage was terminated by a dry spell represented by massive halite deposition at 420 ka (MIS12-11). During MIS10-6 the lake fluctuated between lower and higher stands reaching its highest stand conditions at the late glacial MIS6, after which a significant lake level decline corresponds to the transition to the last interglacial (MIS5) low-stand lake, represented by the uppermost part of the Formation. ?18O values in the primary aragonite range between 6.0 and -1.3 , shifting cyclically between glacial and interglacial intervals. The lowest ?18O values are observed during interglacial stages and may reflect short and intense humid episodes that intermittently interrupted the overall arid conditions. These humid episodes, expressed also by enhanced deposition of travertines and speleothems, seem to characterize the Negev Desert, and in contrast to the overall dominance of the Atlantic-Mediterranean system of rain patterns in the Dead Sea basin, some humid episodes during interglacials may be traced to southern sources.

  15. A combined U-series, radiocarbon and stable isotope approach for constructing a Pleistocene lake hydrograph: an example from Surprise Valley, California

    NASA Astrophysics Data System (ADS)

    Ibarra, D. E.; Weaver, K. L.; Harris, C.; Maher, K.

    2013-12-01

    Lake records and lake hydrographs provide an integrated record of the hydrologic conditions across a watershed. To provide useful constraints on past changes in climate, robust hydrographs require concordance among multiple geochronologic approaches as well as supporting geochemical and hydrologic evidence. Dating shoreline or near-shore lacustrine carbonates using U-series and radiocarbon methods is one approach for developing the age-elevation constraints to construct lake hydrographs. Geochemical analyses (e.g., stable isotopes, elemental ratios, U-series measurements) of modern waters and sediments, as well as the primary carbonate samples, can be used to assess the potential influence of open-system behavior, detrital Th corrections, or pedogenic overprinting on the calculated ages. Additionally, topographic analyses (e.g., basin pour point, shoreline elevations and sample locations) further constrain the spatial relevance and relationships between sample localities. To evaluate the timing and magnitude of the most recent late Pleistocene lake cycle in Surprise Valley, California, we analyzed 111 sub-samples from 22 laminated shoreline tufa samples using U-series disequilibrium geochronology, and pair these analyses with 15 radiocarbon ages. To further assess the radiocarbon and U-series ages, we measured the stable isotope (?18O and ?13C) and elemental (Sr/Ca) signatures of the tufa samples, and characterized the range of (234U/238U) observed in the modern waters and playas within the watershed. Topographic analysis verified that Lake Surprise is a closed, inward draining basin, and demonstrated lateral correspondence between samples from the four targeted shoreline sets. Multiple lines of evidence revealed that samples from the highest shorelines are likely from older, higher lake cycles and were influenced by variable amounts of open-system exchange or pedogenic overprinting. The measured U concentrations of ~300 to 1200 ng/g, with (238U/232Th) from ~3 to 12, and (230Th/232Th) as low as 1.7, required correction procedures to produce accurate ages. Using the Total Sample Dissolution method on suites of >5 sub-samples, we calculated U-series isochron ages using paired 2-D Rosholt isochrons determined by error-weighted linear least squares regressions. We found concordance between most isochron ages and single sample detrital Th corrected ages. Additionally, Rosholt isochron ((238U/232Th) vs. (230Th/232Th)) intercepts and modern carbonate measurements indicate that the (230Th/232Th) of the detrital Th end-member has remained consistent, at a value of ~1.3. Most samples demonstrated concordance between the U-series ages and radiocarbon ages, but four samples had U-series ages that were on average ~1.35 kyr older than the paired radiocarbon ages. Spanning 10 to 30 ka, this new lake hydrograph places the highest lake level, ~176 m above present-day playa, at >15.2 ka. During the Last Glacial Maximum (19 to 26 ka) Lake Surprise stood at moderate levels, at ~80 m above modern playa. This coupled approach to hydrograph construction demonstrates how age-elevation data from multiple geochronologic methods can be corroborated and interpreted within the context of geochemical and topographic analyses.

  16. Enhanced particle scavenging in deep water of the Aleutian Basin revealed by 210Po-210Pb disequilibria

    NASA Astrophysics Data System (ADS)

    Hu, Wangjiang; Chen, Min; Yang, Weifeng; Zhang, Run; Qiu, Yusheng; Zheng, Minfang

    2014-06-01

    The high sedimentation rate but low primary production in surface ocean raised a question whether particles from local upper water column could support high deposition in the Aleutian Basin. Here we first present large 210Po-210Pb disequilibria in deep water of the Aleutian Basin. Dissolved 210Po and 210Pb were depleted relative to 210Pb and 226Ra, respectively, in deep water below 1000 m, as well as decreased with depth, suggesting enhanced particle scavenging in the deep water. The 210Po residence times (1-2 a) in deep water were comparable to those in the upper water column, indicating that 210Po scavenging rates were high in deep water of the Aleutian Basin. The export fluxes of 210Po from the upper 100 m were estimated to be 0.2-0.8 Bq/m2/d, much lower than those in the deep water (7-8 Bq/m2/d). Similarly, POC export fluxes in deep water (24-80 mmolC/m2/d) were higher than those in the upper 100 m (1 mmolC/m2/d). Such a large discrepancy between the upper and deep water suggested that particles from local upper water column could not totally meet the enhanced scavenging in the deep water. Based on mass balance calculations, the extra fluxes of 210Pb and POC imported to deep water were estimated to be 8-12 Bq/m2/d and 22-79 mmolC/m2/d, respectively. The ratio of POC to particulate 210Pb (i.e., POC/PPb) in the extra source was estimated to be 6.5 mmol/Bq, which was lower than that in the Bering Shelf with a mean POC/PPb ratio of 10.9 mmol/Bq, implying that particles in the Bering Shelf could be a potential source for the enhanced particle scavenging in deep water of the Aleutian Basin. However, quantitative and detailed role of ridges and manganese from sediments in particle scavenging in the deep water was unclear, and further studies are necessary.

  17. The origin of the 'fluid' component and its implications for U-Th-Pa disequilibria in island arcs

    NASA Astrophysics Data System (ADS)

    Avanzinelli, R.; Skora, S. E.; Blundy, J.; Elliott, T.

    2011-12-01

    Many arc lavas have two discrete slab-derived components evident from their compositional variations. These components have been interpreted to be melts of subducted sediment and a 'fluid' from the mafic oceanic crust. The 'fluid' signature is seen most clearly in depleted samples that contain the smallest fraction of the sediment component. The provenance of this 'fluid' is reliably pinned by its unradiogenic Pb isotope ratios to be from a MORB-like source. The composition of the 'fluid' phase is marked by strong enrichments in the large, divalent cations, notably Ba, Pb and Sr and (238U/230Th)>1. These characteristics have traditionally been explained by the 'mobility' of such elements in an aqueous fluid. Such fluids are anticipated to be generated during prograde, subduction-metamorphism and to flux elements into the mantle wedge. Yet no experimental dataset of solid-aqueous fluid partitioning replicates the full set of elemental enrichments described above. The recent realisation of the pivotal role of accessory phases in controlling the mobility of elements from the slab provides a more consistent explanation of the chemical characteristics of the 'fluid' phase. Notably rutile and allanite retain the 'immobile' HSFE and REE and fractionate Th from U. The enrichments in the 'fluid' thus simply reflect the displacement of homeless elements. However, Ba will not be mobile until its preferred host, phengite, is exhausted at the wet solidus of the mafic crust. Thus the 'fluid' phase transpires to be a wet melt. The dominant control of accessory phases on the composition of the 'fluid' component also helps in understanding the long-standing puzzle of arc lava 235U-231Pa systematics. By analogy with surface aqueous behaviour, many models have assumed that the 'fluid' adds only U to the mantle wedge, generating 238U-230Th and 235U-231Pa excesses. Yet many lavas with strong 'fluid' signatures and large 238U-230Th excesses have 235U-231Pa deficits. This surprising observation has previously been explained by in-growth, mantle melting models. We have examined the Mariana arc case in detail and show it is difficult to replicate the combined 235U-231Pa-238U-230Th data in a self-consistent manner. In the light of the residual accessory phase model, however, it is apparent that during 'fluid' production the only likely host for the large pentavalent Pa ion is zircon. We thus suggest that the highly variable 235U-231Pa disequilibria of depleted arc lavas worldwide reflects the variable role of residual zircon in the subducted slab.

  18. Growth of north-east Atlantic cold-water coral reefs and mounds during the Holocene: A high resolution U-series and 14C chronology

    NASA Astrophysics Data System (ADS)

    Douarin, Mlanie; Elliot, Mary; Noble, Stephen R.; Sinclair, Daniel; Henry, Lea-Anne; Long, David; Moreton, Steven G.; Murray Roberts, J.

    2013-08-01

    We investigated the Holocene growth history of the Mingulay Reef Complex, a seascape of inshore cold-water coral reefs off western Scotland, using U-series and radiocarbon dating methods. Both chronologies revealed episodic occurrences of the reef framework-forming scleractinian coral Lophelia pertusa during the late Holocene. Downcore U-series dating revealed unprecedented reef growth rates of up to 12 mm a-1 with a mean rate of 3-4 mm a-1. Our study highlighted a persistent hiatus in coral occurrence from 1.4 ka to modern times despite present day conditions being conducive for coral growth. The growth history of the complex was punctuated at least twice by periods of reduced growth rates: 1.75-2.8 ka, 3.2-3.6 ka and to a lesser extent at 3.8-4 ka and at 4.2 ka. Timing of coral hiatuses and reduced reef growth rates at Mingulay were synchronous with those occurring across the wider northern European region, which suggests a close relationship between these ecosystems and large-scale shifts in palaeoenvironmental regimes associated with changes to the North Atlantic subpolar gyre.

  19. Consequences of differential trace element adsorption at melt-solid interfaces on generating U-series excesses during porous melt flow

    NASA Astrophysics Data System (ADS)

    Hersum, T.; Spiegelman, M.; Kelemen, P.

    2006-12-01

    Measurements of U-series secular disequilibrium in lavas offers promising constraints on the rates of melt generation and transport through the mantle and crust. U-series excesses are produced by any mechanism that changes the relative residence time of parent and daughter nuclides. Although the details of U-series melt transport models differ, they all rely on melt-solid partitioning to separate nuclides and this leads to a number of challenges in interpreting observed U-series excesses. It is also not certain how melt-solid partitioning of trace elements determined on a volume or mass proportion basis from laboratory experiments applies to the pore-scale distribution of these trace elements during porous melt flow. Alternatively, the pore-scale distribution of trace elements could be controlled in part by surface-effects, such as adsorption at grain boundaries or grain-boundary partitioning, as inferred from some experiments (e.g. [1-2]). We demonstrate through a simple model of trace element adsorption that surface effects can change the relative residence time of trace elements during porous melt flow. Our approach is to calculate pore-scale, steady-state, melt flow fields in digitized representations of igneous microstructures using a lattice-Boltzmann (LB) method. We then use a Lagrangian random-walk algorithm to calculate individual tracer (atom) trajectories based on the local melt velocity and a stochastic component to model molecular diffusion. Adsorption of tracers is modeled using a Monte-Carlo approach, i.e. tracer trajectories that intersect melt-solid interfaces will "stick" if a random number from a uniform distribution is less than a given probability, p, for adsorption for that specific element. We also allow adsorbed tracers to return to the melt with probability (1- p). Unlike melt-solid partitioning, that controls trace element residence times by the relative mass or volume of solid-phase proportions, our calculations suggest that with adsorption trace element residence times are sensitive to the Peclet (Pe) number (ratio of the product of advection and pore-size to molecular diffusivity) and the geometry and topology of the microstructure. Trace element residence times increase with decreasing Pe as the contribution of random molecular diffusion is maximized and the probability of intersection at melt-solid interfaces is increased. Likewise, trace element residence times increase, at lower Pe, with increased specific (volume normalized) surface area of melt-solid interfaces. Our initial results suggest that surface- effects, such as adsorption, have observable consequences for U-series excesses and might offer a new interpretation of melting and melt transport in the mantle and crust. 1. Hiraga et al. Nature04; 2. Hiraga et al. AM03.

  20. 226Ra-230Th Disequilibria in Magmas from Llaima and Lonquimay Volcanoes, Chile: On the Roles and Rates of Subvolcanic Magmatic Processes.

    NASA Astrophysics Data System (ADS)

    Reubi, O.; Cooper, L. B.; Dungan, M. A.; Bourdon, B.

    2014-12-01

    226Ra excesses in mafic arc magmas are generally attributed to recent (< 8 kyr) addition of slab-fluid to the mantle wedge and/or mantle melting. Preservation of 226Ra-230Th disequilibria from such sources requires short crustal residence times (<< 8 kyr) for these magmas. The correlation between 226Ra excesses and 10Be/Be previously observed for magmas from the Chilean Southern Volcanic Zone (SVZ) contributed to the view that recent slab-fluid additions causes 226Ra excesses in arc magmas1. Our extensive dataset for Llaima and Lonquimay volcanoes (SVZ) shows variations in (226Ra/230Th) for each volcano, and in some cases within single eruptions. These variations span almost the entire SVZ range and question the pertinence of mantle-derived 226Ra-230Th disequilibria models. Llaima and Lonquimay volcanoes differ in terms of their petrology and magmatic evolution. Llaima magmas (51 to 55 wt% SiO2) are predominantly crystal-rich and carry conspicuous evidence for magma mixing and AFC processes. 238U and 231Pa excesses and incompatible trace element ratios are correlated and this can be accounted for by up to 20% assimilation of basement plutonic rocks2. Crustal contamination had a secondary influence on 226Ra-230Th disequilibria. Magmas with the highest AFC contribution have 226Ra-230Th close to equilibrium, implying that (226Ra-230Th) are mostly affected by either differentiation on time scales of ~8 kyr, or more likely, mixing with mush bodies several kyr old. Lonquimay magmas (52 to 64 wt% SiO2) are almost aphyric. Their evolution was controlled by fractional crystallization with limited crustal contamination. (226Ra-230Th) range from moderate 226Ra excesses to small deficits, and are negatively correlated with Ba/Th and MgO. These observations are difficult to reconcile with only slab-fluid addition and mantle melting. We posit that this (226Ra-230Th) range results from diffusive Ra-exchange between young recharge melts and an old crystal mush. A similar process may also explain 226Ra deficits at some other SVZ volcanoes. Thus (226Ra-230Th) in erupted magmas reflect modification of mantle-derived signatures by open-system magmatic processes in the crust. 1Sigmarsson et al., 2002, Earth and Planet. Sc. Lett. 196, 189-196. 2 Reubi et al., 2011, Earth and Planet. Sc. Lett. 303, 37-47.

  1. Linkage disequilibria among (CA){sub n} polymorphisms in the human dystrophin gene and their implications in carrier detection and prenatal diagnosis in Duchenne and Becker musclar dystrophies

    SciTech Connect

    Chakraborty, R.; Zhong, Y.; Andrade, M. de

    1994-06-01

    Four short tandem repeat loci, characterized by length polymorphisms of (CA){sub n} repeats, have been detected within introns 44, 45, 49, and 50 of the human dystrophin gene. The predicted heterozygosites for these loci range from 72 to 93%, and observed allele numbers range from 6 to 19 in 57 normal chromosomes, revealing their high degree of polymorphism. Evidence for significant disequilibria between the loci within introns 49 and 50 is found. These data appear to be consistent with observations of recombination frequencies between these markers and the length of the intron 44 in relation to the entire region. In addition, these four loci are collectively found to be 100% informative in carrier detection/prenatal diagnosis of Becker and Duchenne muscular dystrophies (B/DMD), whereas scoring the (CA){sub n} markers within introns 45 and 49 alone gives a 99.6% success rate. 13 refs., 4 tabs.

  2. Long-term slip rates of the Elsinore-Laguna Salada fault, southern California, by U-series Dating of Pedogenic Carbonate in Progressively Offset Alluvial fan Remnants.

    NASA Astrophysics Data System (ADS)

    Fletcher, K. E.; Rockwell, T. K.; Sharp, W. D.

    2007-12-01

    The Elsinore-Laguna Salada (ELS) fault is one of the principal strands of the San Andreas fault system in southern California, however its seismic potential is often de-emphasized due to previous estimates of a low slip rate. Nevertheless, the fault zone has produced two historic earthquakes over M6, with the 1892 event estimated at >M7; thus further investigation of the long-term slip rate on the ELS fault is warranted. On the western slopes of the Coyote Mountains (CM), southwest Imperial Valley, a series of alluvial fans are progressively offset by the Elsinore fault. These fans can be correlated to their source drainages via distinctive clast assemblages, thereby defining measurable offsets on the fault. Dating of the CM fans (to compute slip rates), however, is challenging. Organic materials appropriate for C-14 dating are rare or absent in the arid, oxidizing environment. Cosmogenic surface exposure techniques are limited by the absence of suitable sample materials and are inapplicable to numerous buried fan remnants that are otherwise excellent strain markers. Pedogenic carbonate datable by U-series, however, occurs in CM soil profiles, ubiquitously developed in fan gravels, and is apparent in deposits as young as ~1 ka. In CM gravels 10's ka and older, carbonate forms continuous, dense, yellow coatings up to 3 mm thick on the undersides of clasts. Powdery white carbonate may completely engulf clasts, but is not dateable. Carefully selected samples of dense, innermost carbonate lamina weighing 10's of milligrams and analyzed by TIMS, are geochemically favorable for precise U-series dating (e.g., U = 1-1.5 ppm, median 238U/232Th ~ 7), and yield reproducible ages for coatings from the same microstratigraphic horizon (e.g., 48.2 ± 2.7 and 49.9 ± 2.2 ka), indicating that U-Th systems have remained closed and that inherited coatings, though present, have been avoided. Accordingly, U-series on pedogenic carbonate provides reliable minimum ages for deposition of host landforms, thereby facilitating determination of maximum bounds on corresponding slip rates. Results to date show that pedogenic carbonate dating in the CM has a useful range of at least 140 ka, thus progressively offset geomorphic surfaces in the CM study area afford the opportunity to examine the pattern of slip on the Elsinore fault over time scales from circa 10 to >100 ka.

  3. The chronology of hand stencils in European Palaeolithic rock art: implications of new U-series results from El Castillo Cave (Cantabria, Spain).

    PubMed

    García-Diez, Marcos; Garrido, Daniel; Hoffmann, Dirk; Pettitt, Paul; Pike, Alistair; Zilhão, Joao

    2015-07-20

    The hand stencils of European Paleolithic art tend to be considered of pre-Magdalenian age and scholars have generally assigned them to the Gravettian period. At El Castillo Cave, application of U-series dating to calcite accretions has established a minimum age of 37,290 years for underlying red hand stencils, implying execution in the earlier part of the Aurignacian if not beforehand. Together with the series of red disks, one of which has a minimum age of 40,800 years, these motifs lie at the base of the El Castillo parietal stratigraphy. The similarity in technique and colour support the notion that both kinds of artistic manifestations are synchronic and define an initial, non-figurative phase of European cave art. However, available data indicate that hand stencils continued to be painted subsequently. Currently, the youngest, reliably dated examples fall in the Late Gravettian, approximately 27,000 years ago. PMID:25615428

  4. Combined ESR/U-series chronology of Acheulian hominid-bearing layers at Trinchera Galería site, Atapuerca, Spain

    USGS Publications Warehouse

    Falguères, Christophe; Bahain, Jean-Jacques; Bischoff, James L.; Pérez-González, Alfredo; Ortega, Ana Isabel; Ollé, Andreu; Quilles, Anita; Ghaleb, Bassam; Moreno, Davinia; Dolo, Jean-Michel; Shao, Qingfeng; Vallverdú, Josep; Carbonell, Eudald; María Bermúdez de Castro, Jose; Arsuaga, Juan Luis

    2013-01-01

    The Sierra de Atapuerca, northern Spain, is known from many prehistoric and palaeontological sites documenting human prehistory in Europe. Three major sites, Gran Dolina, Galería and Sima del Elefante, range in age from the oldest hominin of Western Europe dated to 1.1 to 1.3 Ma (millions of years ago) at Sima del Elefante to c.a. 0.2 Ma on the top of the Galería archaeological sequence. Recently, a chronology based on luminescence methods (Thermoluminescence [TL] and Infrared Stimulated Luminescence [IRSL]) applied to cave sediments was published for the Gran Dolina and Galería sites. The authors proposed for Galería an age of 450 ka (thousands of years ago) for the units lower GIII and GII, suggesting that the human occupation there is younger than the hominid remains of Sima de los Huesos (>530 ka) around 1 km away. In this paper, we present new results obtained by combined Electron Spin Resonance/Uranium-series (ESR/U-series) dating on 20 herbivorous teeth from different levels at the Galería site. They are in agreement with the TL results for the upper part of the stratigraphic sequence (GIV and GIIIb), in the range of between 200 and 250 ka. But for the GIIIa to GIIb levels, the TL ages become abruptly older by 200 ka while ESR ages remain relatively constant. Finally, the TL and ESR data agree in the lowest part of the section (GIIa); both fall in the range of around 350–450 ka. Our results suggest a different interpretation for the GII, GIII and GIV units of Galería and the upper part of Gran Dolina (TD10 and TD11) than obtained by TL. The ESR/U-series results are supported by a Bayesian analysis, which allows a better integration between stratigraphic information and radiometric data.

  5. High resolution analysis of uranium and thorium concentration as well as U-series isotope distributions in a Neanderthal tooth from Payre (Ardche, France) using laser ablation ICP-MS

    NASA Astrophysics Data System (ADS)

    Grn, Rainer; Aubert, Maxime; Joannes-Boyau, Renaud; Moncel, Marie-Hlne

    2008-11-01

    We have mapped U ( 238U) and Th ( 232Th) elemental concentrations as well as U-series isotope distributions in a Neanderthal tooth from the Middle Palaeolithic site of Payre using laser ablation ICP-MS. The U-concentrations in an enamel section varied between 1 and 1500 ppb. The U-concentration maps show that U-migration through the external enamel surface is minute, the bulk of the uranium having migrated internally via the dentine into the enamel. The uranium migration and uptake is critically dependent on the mineralogical structure of the enamel. Increased U-concentrations are observed along lineaments, some of which are associated with cracks, and others may be related to intra-prismatic zones or structural weaknesses reaching from the dentine into the enamel. The uranium concentrations in the dentine vary between about 25,000 and 45,000 ppb. Our systematic mapping of U-concentration and U-series isotopes provides insight into the time domain of U-accumulation. Most of the uranium was accumulated in an early stage of burial, with some much later overprints. None of the uranium concentration and U-series profiles across the root of the tooth complied with a single stage diffusion-adsorption (D-A) model that is used for quality control in U-series dating of bones and teeth. Nevertheless, in the domains that yielded the oldest apparent U-series age estimates, U-leaching could be excluded. This means that the oldest apparent U-series ages of around 200 ka represent a minimum age for this Neanderthal specimen. This is in good agreement with independent age assessments (200-230 ka) for the archaeological layer, in which it was found. The Th elemental concentrations in the dental tissues were generally low (between about 1 and 20 ppb), and show little relationship with the nature of the tissue.

  6. Using U-series Isotopes To Determine Sources Of Pedogenic Carbonates: Comparison Of Natural And Agricultural Soils In The Semi-arid Southern New Mexico And Western Texas

    NASA Astrophysics Data System (ADS)

    Nyachoti, S. K.; Ma, L.; Borrok, D. M.; Jin, L.; Tweedie, C. E.

    2012-12-01

    Pedogenic carbonates commonly precipitate from infiltrating soil water in arid and semi-arid lands and are observed in soils of southern New Mexico and western Texas. These carbonates could form an impermeable layer in the soil horizons impairing water infiltration, thus affecting crop growth and yield. It is important to determine the source of C and Ca in these carbonates and to understand conditions favoring their formation, kinetics and precipitation rates. In this study, major elements and U-series isotopes in bulk calcic soils, and weak acid leachates and residues were measured from one irrigated alfalfa site in the Hueco basin near El Paso, TX and one natural shrubland site on the USDA Jornada experimental range in southern NM. The combined geochemical and isotopic results allow us to determine the formation ages of the carbonates; investigate the mobility of U, Th, and major elements in these soils; and infer for the effects of irrigation on carbonate formation in agricultural soils. Our results show distinctive U and Th isotope systems in the two soil profiles analyzed. For example, (234U/238U) ratios in the Jornada bulk soils decrease from ~1.01 to 0.96 towards the surface, consistent with a preferential loss of 234U over 238U during chemical weathering. At the Jornada site, (238U/232Th) ratios decrease while (230Th/238U) increase towards the surface, consistent with a general depletion of U and the immobility of Th in the natural soils. By contrast at the Alfalfa site, (234U/238U) ratios of bulk soils increase from ~ 0.97 to 1.02 towards the surface, suggesting an additional source of external uranium, most likely the irrigation water from Rio Grande which has a (234U/238U) ratio of ~ 1.5 near El Paso. The (238U/232Th) and (230Th/238U) ratios also imply leaching of U from shallower soils but precipitation in greater depths at Alfalfa site; suggests that partial dissolution and re-precipitation of younger carbonates occur. Calculated carbonate ages from U-series isotopes at the natural Jornada site range from 15.70.1 to 36.90.1kyrs. Near the surface these carbonates are older but at depth, relatively young carbonates indicate partial weathering and overprinting over older carbonates. However, much younger carbonate ages (2.10.2 to 210.1kyrs) are observed at the Alfalfa site. These ages generally decrease with increasing depth with the youngest carbonate ages (2.10.2 kyrs) at ~52 cm. The trend depicted represents a mixture of newly-formed carbonates due to irrigation and pre-existing much older natural carbonates in soils. Evidently young carbonates in the agricultural soils indicate that calcite precipitates out of saline irrigation water. An additional profile is noted with MgO at the Alfalfa site and suggests that Mg2+ is added onto these soils probably from irrigation waters. However at the Jornada site, low MgO contents near the surface indicate loss of Mg most likely by leaching and plant uptake. Our case study highlights the use of U-series and major elements to understand the formation processes of carbonates in both agricultural and natural soils. Clearly, the high salinity of Rio Grande water contributes to elevated amounts of carbonates in agricultural farms and this flux might be important for the overall global mass balance of carbon.

  7. Phenocryst Dynamics in the Magma Chamber of the Guadeloupe Soufriere From U-Th-Ra Disequilibria in 1440A.D. Lavas

    NASA Astrophysics Data System (ADS)

    Touboul, M.; Bourdon, B.

    2005-12-01

    U-Th and Ra analyses of andesitic to dacitic products of the Soufriere last eruption (1440+/-50 A.D.) were performed in order to constraint the time scales and the nature of magmatic processes preceeding eruption. The stratigraphic sequence indicates that, dacitic lavas were first erupted followed by more andesitic lavas, similar to that of the actual dome. Most whole rocks show 238U and 226Ra excess relative to 230Th, like many others arc lavas. Their (226Ra/230Th) activity ratios decrease with differentiation degree from 1.507 to 0.983, whereas the (230Th/238U) ratios increase from 0.942 to 1.003. The groundmasses of the least differentiated lava show a (226Ra/230Th) ratio higher than 1, but all the others are at secular equilibrium. Time dependent fractional crystallization models assuming a common andesitic parental liquid in a vertically zoned magma chamber can explain the compositional variations and U-Th-Ra disequilibria of 1440 Soufriere lavas and groundmasses. The timescales of magma differentiation inferred by fractional crystallization models are of a few ten thousands years for a crystallization rate ranging from 1 to 2.10-5 y-1.The 1440 Soufriere lavas show phenocrysts out of equilibrium with their host melt (complex zoning and overgrowth rims). U-Th disequilibria have been measured in one of the least differentiated lava and provide precious information on their age of crystallization, their origin and the solids dynamics in magma chamber. The crystallization age of 35.0+/-5.9 ky obtained for pyroxenes using U-Th internal isochron is older than the differentiation time of their host lava given by crystallization models but younger than the differentiation time required to get the most evolved composition. That suggests old cumulates remobilization (recycling), whereas the liquids must have evolved separately.Moreover, the magnetite and plagioclase separates attest of a U-Th disturbance. In fact, they do not plot on the isochron defined by the whole rock, the groundmass, the clinopyroxenes and the orthopyroxenes. The magnetite phenocrysts show a very particular U-Th signature. Taken published partitioning coefficient data, they have too high U/Th ratio to have crystallized from any magma of the Soufriere or of Lesser Antilles arc. It thus requires an episode of U-enrichment after crystallization, sufficiently old to allow a strong increase of (230Th/232Th) ratio. Probably dragged from an altered wall-rock, the magnetites suggest an assimilation process. By comparing the (226Ra/230Th) ratios of whole rocks and groundmasses, (226Ra/230Th) ratios of mineral assemblages can be inferred. Greater than 1 for most lavas, they show that some plagioclases have crystallization ages younger than 8000 years which is shorter than the differentiation timescale of their host lavas. It must result of a late crystallisation in their host lava or of a crystallisation from a magma batch injected later than their host lava and followed by their ascent through chamber by flotation. The U-Th-Ra disequilibria of minerals also show evidence for minerals exchanges between the different magma batches by sinking or flotation and of surrounding assimilation.

  8. Timing and intensity of groundwater movement during Egyptian Sahara pluvial periods by U-series analysis of secondary U in ores and carbonates

    NASA Astrophysics Data System (ADS)

    Osmond, J. K.; Dabous, Adel A.

    2004-01-01

    Wet climatic episodes are known to have prevailed in the Egyptian Sahara several times during the late Quaternary, most recently during the Holocene 8000 yr ago. Earlier wet episodes have been recognized as having occurred during the past 300,000 yr and have been dated by U-series methods in speleothems and in lake travertines. We show here that the times of enhanced groundwater movement can also be determined by 230Th/ 234U dating of secondary U in ores of uranium, iron, and phosphate. We also present evidence that such acceleration of groundwater movements is indicated by relatively low 234U/ 238U activity ratios in the secondary uranium. Our new data show that pluvial periods in Egypt occurred during marine oxygen isotope stages 4, 5, 6, and 7 and therefore are consistent with the view that the wet episodes are the results of migration of the tropical monsoonal belt driven primarily by the 23,000-yr precession cycle of the Milankovich curve, modulated by the 100,000-yr eccentricity cycle.

  9. 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."

  10. A multi-isotopic study (U-series, 14C, 13C, 18O) on growth of Arctic fissure calcretes (endostromatolites) from Northern Canada.

    NASA Astrophysics Data System (ADS)

    Ghaleb, B.; Hillaire-Marcel, C.; Deschamps, P.; Lauriol, B.

    2009-05-01

    The chronology of Arctic terrestrial environments is poorly documented due to the scarcity of representative deposits allowing radiometric age determinations. Endostromatolites are secondary carbonate precipitations filling fractures in karstic carbonate terrains found in various sites in Yukon, North-West Territories. Expectations about their use to document environmental change were high. The specimens studied here originate from the Bear Cave Mountains (Yukon). They fill presently unsaturated fissures along cliffs, above karstic formations, within a few meters from the bedrock surface. They occur on southern oriented surfaces, and systematically develop on the outer side surface of the fractures. These concretions are likely of biogenic origin, and are thought to form during periods with relatively warm conditions in the Arctic (i.e., maximum insolation intervals). We report here on 238U, 234U, 230Th, 226Ra, 14C, 13C and 18O analyses of a few thick specimens (2 cm). A first sample yielded inconsistent 14C- and 230Th-ages (ranging from bottom to top of the concretion10-4 ka and 260-55 ka, respectively). Higher resolution measurements in a second sample better illustrate trends from the layer immediately attached to the host rock (here Paleozoic limestone) and the outer, columnar surface of the concretion: i) 230Th/238U activity ratio decrease from near secular equilibrium values to appr. 0.2; ii) 238U- concentrations increase from ~ 2 to ~ 6 ppm, and iii) 226Ra/230Th activity ratios increase from near secular equilibrium values to 1.2. This pattern suggest a pseudo-Rayleigh fractionation process with redistribution of U-series isotopes from the host-rock into the calcrete growth layers, more or less in function of their relative solubility. Some addition of more soluble elements relating to water fluxes cannot be ruled out. Stable carbon isotopes suggest a similar process with a progressive enrichment in 13C (up to +8.5 vs. VPDB) attributed to kinetic fractionation with freezing of water inducing outgazing of an isotopically light CO2 with precipitation of a 13C-enriched calcite. The trend for a progressive enrichment in 14C suggests partial exchanges with the atmospheric CO2 circulating in bedrock fissures. Thus, if 14C and U-series methods cannot be used to set the age of such calcrete, they provide information on their accretion process. In view of the excess 226Ra observed throughout most of the concretion, the overall age of the study specimen cannot exceed a few thousand years (i.e., mid- to late-Holocene), but one cannot estimate any precise duration for the growth phase within this interval. Both their stable isotope properties and complex age structure made them unsuitable for precise paleoclimate reconstructions but allow inferences about the presence of seasonal/occasional active layer above the permafrost during their growth stages.

  11. Beryllium Isotope and Combined Be and U-series Isotope Studies of Volcanic Arcs: Implications for Fluid and Melt Transport Through the Mantle Wedge

    NASA Astrophysics Data System (ADS)

    Morris, J. D.; Ryan, J. G.

    2004-12-01

    Beryllium isotope and combined studies of 10Be/9Be and U-series isotopes in volcanic arcs can 1) map transport of demonstrably slab derived elements through the mantle wedge; 2) certify the relationship of U series isotopes to slab derivation; 3) identify multiple stages in subduction modification of the mantle and constrain their timescales; and 4) speak to element partitioning into fluids and melts from the slab. In the Kurile, Aleutian and Bismarck arcs, 10Be/9Be ratios for lavas from behind the volcanic front are often comparable to, and sometimes greater than, those at the volcanic front, despite the longer path to rear-arc locations, along which 10Be is decaying in transit. Be/Zr ratios show a similar pattern of across-arc increase, without increases in enrichments of Mo and Sn, species which would be mobilized with Be if F-bearing fluids were present. The simplest interpretation is that sediment melting, and its contribution to the mantle wedge, is greater behind the front than at the volcanic front. Despite evidence for an increasing sediment melt contribution behind the front, volcanoes from the Kuriles contain progressively less B, Pb, As and Sb with increasing depth to the slab, indicating that fluid processes updip of about 180 km (beginning in the shallow forearc) strip these elements nearly quantitatively from the sedimentary portion of the downgoing slab. For studies published to date (Aleutians, Central America, S. Chile, Bismarck, Mariana) 10Be/9Be ratios are generally highest for samples plotting furthest from the 238U-230Th equiline (i.e. highest 238U/232Th, 230Th/232Th, or both). In lavas from the Southern Volcanic Zone (SVZ) of S. Chile (Sigmarsson et al., EPSL 2002), U excess (Uxs), Ra excess (Raxs) and 10Be/9Be are strongly correlated (r2=0.81-0.94). This argues that U enrichment and in some cases Ra enrichment in arc lavas is related to slab processes that are capable of mobilizing 10Be out of the sediment column, rather than reflecting only dynamic melting processes or element partitioning in a hydrous mantle wedge. If U and Ra are thought to be carried in a fluid from the altered oceanic crust, that fluid must also carry sediment-derived elements, at least in the SVZ. In Nicaragua, the Aleutians and S. Chile, volcano 10Be/9Be ratios correlate well with 230Th/232Th, 143Nd/144Nd and Uxs and Raxs, respectively. The well constrained mixing lines require that both the subducted component and the mantle to which it is added be relatively homogenous for these slab-derived tracers. At zero 10Be (i.e. prior to sediment addition within the last 1-2 Ma), the Nicaraguan mantle is characterized by high Ba/La, 87Sr/86Sr and 230Th/232Th significantly elevated above MORB or OIB values, attributed to earlier subduction modification of the mantle (Reagan et al., GCA 1994). In the SVZ of Southern Chile, at zero 10Be, the 230Th/232Th of the inferred mantle source is ~0.9, implying sediment addition prior to the more recent event that introduced 10Be. By contrast, at zero 10Be, the inferred Aleutian mantle has a 143Nd/144Nd ratio of 0.5131, suggesting little or no prior sediment addition to the mantle.

  12. Origins of large-volume, compositionally zoned volcanic eruptions: New constraints from U-series isotopes and numerical thermal modeling for the 1912 Katmai-Novarupta eruption

    USGS Publications Warehouse

    Turner, Simon; Sandiford, Mike; Reagan, Mark; Hawkesworth, Chris; Hildreth, Wes

    2010-01-01

    We present the results of a combined U-series isotope and numerical modeling study of the 1912 Katmai-Novarupta eruption in Alaska. A stratigraphically constrained set of samples have compositions that range from basalt through basaltic andesite, andesite, dacite, and rhyolite. The major and trace element range can be modeled by 8090% closed-system crystal fractionation over a temperature interval from 1279C to 719C at 100 MPa, with an implied volume of parental basalt of ?65 km3. Numerical models suggest, for wall rock temperatures appropriate to this depth, that 90% of this volume of magma would cool and crystallize over this temperature interval within a few tens of kiloyears. However, the range in 87Sr/86Sr, (230Th/238U), and (226Ra/230Th) requires open-system processes. Assimilation of the host sediments can replicate the range of Sr isotopes. The variation of (226Ra/230Th) ratios in the basalt to andesite compositional range requires that these were generated less than several thousand years before eruption. Residence times for dacites are close to 8000 years, whereas the rhyolites appear to be 50200 kyr old. Thus, the magmas that erupted within only 60 h had a wide range of crustal residence times. Nevertheless, they were emplaced in the same thermal regime and evolved along similar liquid lines of descent from parental magmas with similar compositions. The system was built progressively with multiple inputs providing both mass and heat, some of which led to thawing of older silicic material that provided much of the rhyolite.

  13. Na, K, Ca, Mg, and U-series in fossil bone and the proposal of a radial diffusion-adsorption model of uranium uptake.

    PubMed

    Cid, A S; Anjos, R M; Zamboni, C B; Cardoso, R; Muniz, M; Corona, A; Valladares, D L; Kovacs, L; Macario, K; Perea, D; Goso, C; Velasco, H

    2014-10-01

    Fossil bones are often the only materials available for chronological reconstruction of important archeological sites. However, since bone is an open system for uranium, it cannot be dated directly and therefore it is necessary to develop models for the U uptake. Hence, a radial diffusion-adsorption (RDA) model is described. Unlike the classic diffusion-adsorption (D-A) model, RDA uses a cylindrical geometry to describe the U uptake in fossil bones. The model was applied across a transverse section of a tibia of an extinct megamammal Macrauchenia patachonica from the La Paz Local Fauna, Montevideo State, Uruguay. Measurements of spatial distribution of Na, K, Ca, and Mg were also performed by neutron activation analysis (NAA). Gamma-ray spectrometric U-series dating was applied to determine the age of the bone sample. From U concentration profile, it was possible to observe the occurrence of a relatively slow and continuous uranium uptake under constant conditions that had not yet reached equilibrium, since the uranium distribution is a ?-shaped closed-system. Predictions of the RDA model were obtained for a specific geochemical scenario, indicating that the effective diffusion coefficient D/R in this fossil bone is (2.4 0.6)10(-12) cm(2)s(-1). Mean values of Na, K, Ca, and Mg contents along the radial line of the fossil tibia are consistent with the expected behavior for spatial distributions of these mineral elements across a modern bone section. This result indicates that the fossil tibia may have its mineral structure preserved. PMID:24953228

  14. Sea-level history of the past two interglacial periods: New evidence from U-series dating of reef corals from south Florida

    USGS Publications Warehouse

    Muhs, D.R.; Simmons, K.R.; Schumann, R.R.; Halley, R.B.

    2011-01-01

    As a future warm-climate analog, much attention has been directed to studies of the Last Interglacial period or marine isotope substage (MIS) 5.5, which occurred ???120,000 years ago. Nevertheless, there are still uncertainties with respect to its duration, warmth and magnitude of sea-level rise. Here we present new data from tectonically stable peninsular Florida and the Florida Keys that provide estimates of the timing and magnitude of sea-level rise during the Last Interglacial period. The Last Interglacial high sea stand in south Florida is recorded by the Key Largo Limestone, a fossil reef complex, and the Miami Limestone, an oolitic marine sediment. Thirty-five new, high-precision, uranium-series ages of fossil corals from the Key Largo Limestone indicate that sea level was significantly above present for at least 9000 years during the Last Interglacial period, and possibly longer. Ooids from the Miami Limestone show open-system histories with respect to U-series dating, but show a clear linear trend toward an age of ???120 ka, correlating this unit with the Last Interglacial corals of the Key Largo Limestone. Older fossil reefs at three localities in the Florida Keys have ages of ???200 ka and probably correlate to MIS 7. These reefs imply sea level near or slightly above present during the penultimate interglacial period. Elevation measurements of both the Key Largo Limestone and the Miami Limestone indicate that local (relative) sea level was at least 6.6 m, and possibly as much as 8.3 m higher than present during the Last Interglacial period. ?? 2010.

  15. U-series isotope systematics of mafic magmas from central Oregon: Implications for fluid involvement and melting processes in the Cascade arc

    NASA Astrophysics Data System (ADS)

    Mitchell, Euan C.; Asmerom, Yemane

    2011-12-01

    The Cascade arc is the warm-slab subduction zone global end member, where a broad variety of primitive magmas with highly variable slab fluid signatures have erupted in close spatial and temporal proximity. A number of petrogenetic models have been proposed to explain the occurrence of such diverse magmas, but the source(s) of these magmas and the timing of fluid addition to the sub-arc mantle remain controversial. We present uranium-series isotope data ( 238U- 230Th- 226Ra) for eighteen mafic lavas from the Three Sisters region of the central Oregon Cascades, and for a further six lavas from the rear-arc Newberry Volcano. The majority of these samples have geochemical characteristics (e.g. Nb/Zr, Ba/Zr, 87Sr/ 86Sr) consistent with previously described calc-alkaline basalts from this region of the arc, and indicative of limited fluid involvement at some stage in their genesis. Trace element and long-lived radiogenic isotope modeling suggests that this fluid was derived from dehydration of subducting sediments, and was added to an enriched, garnet-bearing mantle wedge source. The trace element systematics of the lavas are consistent with small degree (< 10%) melts of this fluid-modified source. All samples display ( 230Th/ 238U) and ( 226Ra/ 230Th) ≥ 1, similar to values measured in fresh MORB and other parts of the arc. Results of a dynamic melting model support the interpretation that these lavas are small degree melts of an asthenospheric source, and do not allow for a lithospheric mantle source. However, the U-series data do not permit us to determine whether fluid addition was the trigger for melting, or whether the lavas were generated from a secular equilibrium source that had experienced fluid addition > 350 ka prior to melting. Regardless, modern fluid input is limited and melting is dominantly occurring in response to upwelling and decompression.

  16. Rapid crystal recycling at Krafla Volcano, Iceland, inferred from oxygen-isotope and trace- element compositions and U-Th-Ra disequilibria in plagioclase

    NASA Astrophysics Data System (ADS)

    Cooper, K. M.; Sims, K. W.; Eiler, J. M.; Banerjee, N. R.

    2008-12-01

    The Icelandic central volcano of Krafla exhibits increasing assimilation of hydrothermally-altered crust with increasing differentiation of magmas, as evidenced by decreasing δ18O with decreasing MgO (Nicholson et al., 1991, J Pet 32, p.1005). The Krafla Fires eruption (1975-84) produced two different magma compositions simultaneously: quartz tholeiites near the center of the volcano, and olivine tholeiites north of the central volcano (Gronvold et al., 2008, Goldschmidt abstract). Examination of crystals in these magmas has the potential to provide information about the nature and timescales of mixing of distinct magmas and assimilation of crustal material at Krafla. We present oxygen-isotope compositions, trace-element compositions, and 238U-230Th-226Ra disequilibria measured in plagioclase crystals from samples of lavas erupted during two phases of the Krafla Fires eruption (ol tholeiite erupted Jan-Feb 1981, and qz tholeiite erupted Nov 1981). Oxygen-isotope data for multiple size fractions of plagioclase show a decrease in δ18O with increasing crystal size for the ol tholeiite (from ~4.1 permil to 3.5 permil), whereas there is no clear relationship between plagioclase size and oxygen-isotope composition in the qtz tholeiite (all size fractions average 4.1-4.3 permil). Furthermore, all measured plagioclase have δ18O lower than would be in equilibrium with the whole rock measurements (by up to 1.5 permil). These data imply that (1) few or none of the measured crystals precipitated from the host liquids, and (2) the crystals were entrained in the host magmas shortly prior to eruption, allowing them to maintain oxygen isotopic disequilibrium and heterogeneity within the crystal populations. These inferences are corroborated by trace element compositions measured in plagioclase by laser-ablation ICPMS, as the majority of analyzed points have Ba and Sr concentrations inconsistent with equilibrium partitioning between crystals and liquid. Furthermore, in the case of the olivine tholeiite, large (>125 microns) and small (<125 microns) size fractions of plagioclase have distinct REE patterns, suggesting that at least two foreign crystal components are present within this magma. Ra-Th model ages of all analyzed plagioclase fractions are undefined after correction for Ra/Ba fractionation during crystallization, suggesting that the liquid from which the measured plagioclase precipitated had higher Ra/Ba ratios than the host liquids. The preservation of Ra-Th disequilibria in the plagioclase crystals indicates that they (and presumably the magma that was their source) is young (<10 ka). The low δ18O of plagioclase suggests that the plagioclase source had assimilated more low-δ18O crustal material than the host magmas. However, δ18O of a magma in equilibrium with the plagioclase would still lie within the range for mafic magmas from Krafla, and the major-element compositions of analyzed plagioclase are close to equilibrium with the host liquids, suggesting that the plagioclase crystals are antecrysts derived from a crystal mush or recently-solidified intrusion of basaltic magma within the Krafla reservoir system. In the case of the olivine tholeiite, more than one population of antecrysts are present, implying interaction with crystals derived from more than one earlier magma body, and suggesting that this process is common beneath Krafla.

  17. Long-term behaviour of continental hydrothermal systems: - U-series study of hydrothermal carbonates from the French Massif Central (Allier Valley)

    NASA Astrophysics Data System (ADS)

    Rihs, Sophie; Condomines, Michel; Poidevin, Jean-Louis

    2000-09-01

    U-series dating of hydrothermal carbonates, deposited by CO 2-rich thermo-mineral waters of the French Massif Central, provides new insights on the long-term behaviour of a continental hydrothermal system. Dating of aragonite veins and travertines impregnating old terrace levels of the Allier river allowed identification of the main episodes of surface deposition, and thus factors likely to influence these circulations. Fifteen layers from three veins and four travertines from two separate areas were analysed. Sr isotope compositions were also measured on vein samples. The results show that this region was subjected to at least 3 main episodes of surface or near surface hydrothermal deposition: 253 to 208 ky, 135 to 100 ky and less than 8 ky. Comparison of these ages with a global climatic curve indicates that preferential deposition of carbonates occurs during warm periods, suggesting a strong influence of climatic conditions on the hydrothermal system. It is suggested that this climatic influence does not necessarily imply the absence of carbonate deposition during cold and dry periods, but rather that carbonate precipitation might occur at depth before the geothermal fluids reach the surface. In addition, the isotope compositions of fluids recorded by the 87Sr/ 86Sr and ( 234U/ 238U) initial ratios in the aragonite veins from Coudes remained remarkably constant over 250 ky, ranging from 0.71360 to 0.71371 and from 3.10 to 3.39 respectively. The two samples coming from Saladis show a slightly higher ( 234U/ 238U) initial ratio around 3.95. The constancy of these ratios over such a long period suggests a hydrothermal system in a near steady state with respect to water-rock interaction. We thus propose a possible model allowing a conservative steady state despite variations in the water recharge rates, in response to the climatic variations. The difference between ( 234U/ 238U) initial ratios measured in the Coudes and Saladis systems suggests the existence of two separate reservoirs and constrains their lateral extension to a few km at most.

  18. Radioactive Wastes.

    PubMed

    Choudri, B S; Baawain, Mahad

    2015-10-01

    Papers reviewed herein present a general overview of radioactive waste activities around the world in 2014. These include safety assessments, decommission and decontamination of nuclear facilities, fusion facilities, transportation and management solutions for the final disposal of low and high level radioactive wastes (LLW and HLW), interim storage and final disposal options for spent fuel (SF), and tritiated wastes, with a focus on environmental impacts due to the mobility of radionuclides in water, soil and ecosystem alongwith other progress made in the management of radioactive wastes. PMID:26420096

  19. Radioactive Iodine

    MedlinePLUS

    ... form of iodide, is made into two radioactive isotopes that are commonly used in patients with thyroid ... thyroid cells ). The radiation emitted by each these isotopes can be detected from outside the patient to ...

  20. Simulated Radioactivity

    ERIC Educational Resources Information Center

    Boettler, James L.

    1972-01-01

    Describes the errors in the sugar-cube experiment related to radioactivity as described in Project Physics course. The discussion considers some of the steps overlooked in the experiment and generalizes the theory beyond the sugar-cube stage. (PS)

  1. Concentrating Radioactivity

    ERIC Educational Resources Information Center

    Herrmann, Richard A.

    1974-01-01

    By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

  2. Radioactivity Calculations

    ERIC Educational Resources Information Center

    Onega, Ronald J.

    1969-01-01

    Three problems in radioactive buildup and decay are presented and solved. Matrix algebra is used to solve the second problem. The third problem deals with flux depression and is solved by the use of differential equations. (LC)

  3. Radioactive Waste.

    ERIC Educational Resources Information Center

    Blaylock, B. G.

    1978-01-01

    Presents a literature review of radioactive waste disposal, covering publications of 1976-77. Some of the studies included are: (1) high-level and long-lived wastes, and (2) release and burial of low-level wastes. A list of 42 references is also presented. (HM)

  4. Radioactive wastes

    SciTech Connect

    Devarakonda, M.S.; Hickox, J.A.

    1996-11-01

    This paper provides a review of literature published in 1995 on the subject of radioactive wastes. Topics covered include: national programs; waste repositories; mixed wastes; decontamination and decommissioning; remedial actions and treatment; and environmental occurrence and transport of radionuclides. 155 refs.

  5. Improved spatial resolution for U-series dating of opal at Yucca Mountain, Nevada, USA, using ion-microprobe and microdigestion methods

    USGS Publications Warehouse

    Paces, J.B.; Neymark, L.A.; Wooden, J.L.; Persing, H.M.

    2004-01-01

    Two novel methods of in situ isotope analysis, ion microprobe and microdigestion, were used for 230Th/U and 234U/238U dating of finely laminated opal hemispheres formed in unsaturated felsic tuff at Yucca Mountain, Nevada, proposed site for a high-level radioactive waste repository. Both methods allow analysis of layers as many as several orders of magnitude thinner than standard methods using total hemisphere digestion that were reported previously. Average growth rates calculated from data at this improved spatial resolution verified that opal grew at extremely slow rates over the last million years. Growth rates of 0.58 and 0.69 mm/m.y. were obtained for the outer 305 and 740 ??m of two opal hemispheres analyzed by ion microprobe, and 0.68 mm/m.y. for the outer 22 ??m of one of these same hemispheres analyzed by sequential microdigestion. These Pleistocene growth rates are 2 to 10 times slower than those calculated for older secondary calcite and silica mineral coatings deposited over the last 5 to 10 m.y. dated by the U-Pb method and may reflect differences between Miocene and Pleistocene seepage flux. The microdigestion data also imply that opal growth rates may have varied over the last 40 k.y. These data are the first indication that growth rates and associated seepage in the proposed repository horizon may correlate with changes in late Pleistocene climate, involving faster growth during wetter, cooler climates (glacial maximum), slower growth during transition climates, and no growth during the most arid climate (modern). Data collected at this refined spatial scale may lead to a better understanding of the hydrologic variability expected within the thick unsaturated zone at Yucca Mountain over the time scale of interest for radioactive waste isolation. ?? 2004 Elsevier Ltd.

  6. 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(-1) in the Ganga-Indus headwaters. Data on the abundance and distribution of black shales in their drainage basin are needed to test if this requirement can be met. (234)U/(238)U activity ratios in both carbonates and black shales are at or near equilibrium, thus preferential mobilization of (234)U from these deposits, if any, is within analytical uncertainties. (230)Th is equivalent to or in excess of (238)U in most of the carbonates. (230)Th/(238)U>1 indicates that during weathering, uranium is lost preferentially over Th. (232)Th concentrations in carbonates are generally quite low, <0.5 microg g(-1), though with a wide range, 0.01-4.8 microg g(-1). The variation in its concentrations seem to be regulated by aluminosilicate content of the carbonates as evident from the strong positive correlation between (232)Th and Al. PMID:12634002

  7. 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. PMID:19186064

  8. Levels of sup 137 Cs and natural radioactivity in Saudi Arabian soil

    SciTech Connect

    Abulfarai, W.; Abdul-Majid, S. )

    1991-01-01

    After the Chernobyl accident, there was concern about contamination from the radioactive plume reaching Saudi Arabia. Cesium-137 concentration in the soil was measured to determine the degree of contamination from the accident. The concentrations of {sup 40}K, {sup 214}Bi, and {sup 228}Ac were determined as well. Bismuth-214 is a member of the {sup 238}U series, while {sup 228}Ac is from the {sup 238}Th series. Each of these isotopes emits several well-resolved photons of relatively high intensity per disintegration.

  9. Why are so many arc magmas close to 238U- 230Th radioactive equilibrium?

    NASA Astrophysics Data System (ADS)

    Condomines, Michel; Sigmarsson, Olgeir

    1993-09-01

    New analyses of 238U- 230Th disequilibria are reported for four active volcanoes: Merapi and Krakatoa in the Sunda arc (Indonesia), Masaya in Central America (Nicaragua), and Ambrym in the New Hebrides island arc. Despite a large range in ( 230Th /232Th ) ratios (from 0.65 in Merapi andesites to 2.5 in Masaya basalts), 238U and 230Th are close to radioactive equilibrium, as in many other arc magmas. In several mantle sources, Th/U ratios have clearly been modified by metasomatic processes associated with subduction. This is demonstrated in Central America by the correlation between ( 230Th /232Th ) and 10Be /9Be ratios for several active volcanoes along the arc. It is proposed that the 238U- 230Th radioactive equilibrium found in many arc magmas is the result of disequilibrium melting involving an easily melted, slab-derived, metasomatic component which dominates the uranium and thorium budget of the mantle sources. The departure from equilibrium may be either due to mixing with 230Th enriched melts derived from unmetasomatized mantle sources or to a late stage uranium addition by fluids. This latter process, producing uranium enriched magmas, has a greater influence in uranium and thorium poor magmas.

  10. Radioactivity in local and imported kaolin types used in Egypt.

    PubMed

    el-Dine, N Walley; Sroor, A; el-Shershaby, A; el-Bahi, S M; Ahmed, F

    2004-01-01

    Natural radioactive materials are present in all geological rocks in varying amounts, they are easily mobilized in the environment, and can reach hazardous radiological levels under certain conditions, requiring precautions to be taken. The present study deals with 50 geological samples of local (Tushki and Kalabsha in upper Egypt) and imported (southeast Asia and Turkey) kaolin types. The samples were analyzed by gamma-ray spectroscopy using a HPGe detector. The activity concentrations of 232Th and 238U series and 40K and the contents (in ppm) are given. The radium equivalent activity varied from 187.8 to 10185.19 Bq/kg. 137Cs was found in a range of 0.23-8.5 Bq/kg, for the local samples. The kaolin in Tushki area was suitable for industrial use. PMID:14687643

  11. Rapid Ascent of Aphyric Mantle Melts through the Overriding Crust in Subduction Zones: Evidence from Variable Uranium-Series Disequilibria, Amorphous Hydrous Alteration Microtextures in Crystal Rims, and Two-Pyroxene Pseudo-Decompression Paths

    NASA Astrophysics Data System (ADS)

    Zellmer, G. F.; Freymuth, H.; Hsieh, H. H.; Hwang, S. L.; Iizuka, Y.; Miller, C. A.; Rubin, K. H.; Sakamoto, N.; Yurimoto, H.

    2014-12-01

    Volcanic hazard mitigation at subduction zones critically depends on knowledge of magma generation and ascent processes and timescales. Two diametrically opposite scenarios are presently debated: One paradigm is the generation of low-silica (basaltic) melts in the mantle wedge, followed by protracted sub-liquidus magma ascent and evolution through crystal growth and fractionation in crustal reservoirs, which are tapped during volcanic eruptions. In contrast, a diametrically opposite model favours the generation of higher silica melts in the mantle or in a lower crustal hot zone, followed by rapid decompression to the surface under super-liquidus conditions. In the latter case, crystals are picked up during magma ascent, and are in the process of dissolving. We present multiple lines of evidence that point to crystal uptake as the principal processes by which arc melts acquire their crystal cargo: (i) variable 234U-238U disequilibria in mineral separates; (ii) hydrous mineral rims with amorphous alteration textures; and (iii) two-pyroxene pseudo-decompression paths; cf. Zellmer et al. (2014a,b,c), doi: 10.1144/SP385.3 and 10.1144/SP385.9 and 10.1144/SP410.1. These observations point to a scarcity of true phenocrysts in many arc magmas, and thus to decompression of aphyric melts that take up their crystal cargo during ascent. The data imply that many hydrous wedge melts are more silica-rich than basalts and achieve super-liquidus conditions during rapid ascent from great depth.

  12. 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.

  13. Radioactive iodine uptake

    MedlinePLUS

    Iodine uptake test; RAIU ... to swallow a liquid or capsule containing radioactive iodine. After a certain period of time (usually 4 ... have: Diarrhea (may decrease absorption of the radioactive iodine) Had recent CT scans using intravenous or oral ...

  14. Procedures for radioactive I-131

    SciTech Connect

    Sharma, S.C. )

    1988-12-01

    Details of the radioactive I-131 administration and radiation safety considerations are presented. Topics covered include patient survey, radioactive labelling, levels in patients containing radioactivity, hospital discharge of radioactive patients, and nursing procedures.

  15. Radioactive impact in sediments from an estuarine system affected by industrial wastes releases.

    PubMed

    Bolvar, Juan Pedro; Garca-Tenorio, Rafael; Mas, Jos Luis; Vaca, Federico

    2002-03-01

    A big fertilizer industrial complex and a vast extension of phosphogypsum piles (12 km2), sited in the estuary formed by the Odiel and Tinto river mouths (southwest of Spain), are producing an unambiguous radioactive impact in their surrounding aquatic environment through radionuclides from the U-series. The levels and distribution of radionuclides in sediments from this estuarine system have been determined. The analyses of radionuclide concentrations and activity ratios have provided us with an interesting information to evaluate the extension, degree and routes of the radioactive impact, as well as for the knowledge of the different pathways followed for the radioactive contamination to disturb this natural system. The obtained results indicate that the main pathway of radioactive contamination of the estuary is through the dissolution in its waters of the radionuclides released by the industrial activities and their later fixation on the particulate materials. Tidal activity also plays an important role in the transport and homogenization along the estuary of the radioactivity released from the fertilizer plants. PMID:11934113

  16. Formation of Pedogenic Carbonates in the Semi-arid Rio Grande Valley: Insights from Carbon, Major elements, and U-series isotopes in Natural and Agricultural Soils of Southern New Mexico and Western Texas

    NASA Astrophysics Data System (ADS)

    Nyachoti, S. K.; Ma, L.; Jin, L.; Tweedie, C. E.

    2013-12-01

    Accumulation of pedogenic carbonates in arid and semi-arid soils affects soil porosity, water infiltration, and global carbon cycle. We investigate formation rates of these carbonates under different land uses in the semi-arid Rio Grande valley using mineralogy, concentrations of major elements (including C), and U-series isotopes. Our study sites include one alfalfa farm (Alfalfa) at El Paso, TX under frequent irrigation with saline water from the Rio Grande River, and one natural shrub field under natural rainfall conditions at the USDA Jornada Experimental Range (Jornada) in NM. Major minerals observed at Alfalfa and Jornada are calcite, quartz, and feldspars. Calcite/quartz ratios increase upward in the profile at Alfalfa, suggesting formation of carbonates in shallow soils. Consistently, total carbon increases toward the soil surface at Alfalfa, contributed by both soil organic carbon and soil inorganic carbon (pedogenic carbonates). Concentrations of major elements (e.g Ca, Mg, and Sr) also increase toward the surface at Alfalfa, suggesting surface addition. Alternating trends of enrichment and depletion are observed throughout the soil profiles. In contrast, calcite/quartz ratios decrease toward the surface at Jornada, indicative of leaching at shallow soils and redeposition of calcite at depth. This is in agreement with high soil inorganic carbon contents measured at depth. At Jornada however, the Ca, Mg and Sr concentrations decrease toward the surface, showing typical depletion profiles. (234U/238U) activity ratios in bulk soils increase upward at Alfalfa while at Jornada (234U/238U) ratios decrease toward the surface. (234U/238U) ratios at Alfalfa suggest surface addition of U onto shallow soils probably from irrigation water, which is known to have high (234U/238U) ratios. Jornada shows preferential loss of 234U upward. U-series disequilibrium in pedogenic carbonates enables calculation of their formation ages. At Alfalfa, carbonate ages range from 2.2 1.7 ka to 15 17 ka. Furthermore, these ages decrease with depth suggesting faster carbonate precipitation downward. These ages most likely represent mixing of natural old carbonates and recently formed carbonates due to frequent irrigation. The carbonates at Jornada however, are much older ranging from 14.5 6.8 ka to 117 26 ka. Older carbonates at Jornada could be due to slower water infiltration from limited rainfall, Ca and insufficient dissolved inorganic carbon (DIC) thus slow formation of pedogenic carbonates. Our findings show differing carbonate formation rates in arid zones. In agricultural settings, carbonates are precipitated faster due to loading of Ca and DIC from flood irrigation. Soil organic carbon is also an important C reservoir, releasing soil CO2 to form carbonates. In natural settings however, relatively older carbonate suggest slower precipitation kinetics.

  17. 238U-230Th-226Ra disequilibria in dacite and plagioclase from the 2004-2005 eruption of Mount St. Helens: Chapter 36 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Cooper, Kari M.; Donnelly, Carrie T.

    2008-01-01

    230Th)/(232Th) measured for the 1980s reference suite. However, (230Th)/(232Th) for plagioclase separates for dome samples erupted during October and November 2004 are significantly different from corresponding whole-rock values, which suggests that a large fraction (>30 percent) of crystals in each sample are foreign to the host liquid. Furthermore, plagioclase in the two 2004 samples have U-series characteristics distinct from each other and from plagioclase in dacite erupted in 1982, indicating that (1) the current eruption must include a component of crystals (and potentially associated magma) that were not sampled by the 1980-86 eruption, and (2) dacite magmas erupted only a month apart in 2004 contain different populations of crystals, indicating that this foreign component is highly heterogeneous within the 2004-5 magma reservoir.

  18. ORNL radioactive waste operations

    SciTech Connect

    Sease, J.D.; King, E.M.; Coobs, J.H.; Row, T.H.

    1982-01-01

    Since its beginning in 1943, ORNL has generated large amounts of solid, liquid, and gaseous radioactive waste material as a by-product of the basic research and development work carried out at the laboratory. The waste system at ORNL has been continually modified and updated to keep pace with the changing release requirements for radioactive wastes. Major upgrading projects are currently in progress. The operating record of ORNL waste operation has been excellent over many years. Recent surveillance of radioactivity in the Oak Ridge environs indicates that atmospheric concentrations of radioactivity were not significantly different from other areas in East Tennesseee. Concentrations of radioactivity in the Clinch River and in fish collected from the river were less than 4% of the permissible concentration and intake guides for individuals in the offsite environment. While some radioactivity was released to the environment from plant operations, the concentrations in all of the media sampled were well below established standards.

  19. Radioactivity and food

    SciTech Connect

    Olszyna-Marzys, A.E. )

    1990-03-01

    Two topics relating to radioactivity and food are discussed: food irradiation for preservation purposes, and food contamination from radioactive substances. Food irradiation involves the use of electromagnetic energy (x and gamma rays) emitted by radioactive substances or produced by machine in order to destroy the insects and microorganisms present and prevent germination. The sanitary and economic advantages of treating food in this way are discussed. Numerous studies have confirmed that under strictly controlled conditions no undesirable changes take place in food that has been irradiated nor is radioactivity induced. Reference is made to the accident at the Chernobyl nuclear power station, which aroused public concern about irradiated food. The events surrounding the accident are reviewed, and its consequences with regard to contamination of different foods with radioactive substances, particularly iodine-131 and cesium-137, are described. Also discussed are the steps that have been taken by different international organizations to set limits on acceptable radioactivity in food.15 references.

  20. [Radioactivity and food].

    PubMed

    Olszyna-Marzys, A E

    1990-03-01

    Two topics relating to radioactivity and food are discussed: food irradiation for preservation purposes, and food contamination from radioactive substances. Food irradiation involves the use of electromagnetic energy (x and gamma rays) emitted by radioactive substances or produced by machine in order to destroy the insects and microorganisms present and prevent germination. The sanitary and economic advantages of treating food in this way are discussed. Numerous studies have confirmed that under strictly controlled conditions no undesirable changes take place in food that has been irradiated nor is radioactivity induced. Reference is made to the accident at the Chernobyl nuclear power station, which aroused public concern about irradiated food. The events surrounding the accident are reviewed, and its consequences with regard to contamination of different foods with radioactive substances, particularly iodine-131 and cesium-137, are described. Also discussed are the steps that have been taken by different international organizations to set limits on acceptable radioactivity in food. PMID:2143071

  1. Radioactive Waste Management Basis

    SciTech Connect

    Perkins, B K

    2009-06-03

    The purpose of this Radioactive Waste Management Basis is to describe the systematic approach for planning, executing, and evaluating the management of radioactive waste at LLNL. The implementation of this document will ensure that waste management activities at LLNL are conducted in compliance with the requirements of DOE Order 435.1, Radioactive Waste Management, and the Implementation Guide for DOE Manual 435.1-1, Radioactive Waste Management Manual. Technical justification is provided where methods for meeting the requirements of DOE Order 435.1 deviate from the DOE Manual 435.1-1 and Implementation Guide.

  2. Radioactive Wastes. Revised.

    ERIC Educational Resources Information Center

    Fox, Charles H.

    This publication is one of a series of information booklets for the general public published by the United States Atomic Energy Commission. This booklet deals with the handling, processing and disposal of radioactive wastes. Among the topics discussed are: The Nature of Radioactive Wastes; Waste Management; and Research and Development. There are…

  3. Temporary Personal Radioactivity

    ERIC Educational Resources Information Center

    Myers, Fred

    2012-01-01

    As part of a bone scan procedure to look for the spread of prostate cancer, I was injected with radioactive technetium. In an effort to occupy/distract my mind, I used a Geiger counter to determine if the radioactive count obeyed the inverse-square law as a sensor was moved away from my bladder by incremental distances. (Contains 1 table and 2

  4. A Remote Radioactivity Experiment

    ERIC Educational Resources Information Center

    Jona, Kemi; Vondracek, Mark

    2013-01-01

    Imagine a high school with very few experimental resources and limited budgets that prevent the purchase of even basic laboratory equipment. For example, many high schools do not have the means of experimentally studying radioactivity because they lack Geiger counters and/or good radioactive sources. This was the case at the first high school one

  5. Radioactive waste disposal package

    DOEpatents

    Lampe, Robert F. (Bethel Park, PA)

    1986-01-01

    A radioactive waste disposal package comprising a canister for containing vitrified radioactive waste material and a sealed outer shell encapsulating the canister. A solid block of filler material is supported in said shell and convertible into a liquid state for flow into the space between the canister and outer shell and subsequently hardened to form a solid, impervious layer occupying such space.

  6. A Remote Radioactivity Experiment

    ERIC Educational Resources Information Center

    Jona, Kemi; Vondracek, Mark

    2013-01-01

    Imagine a high school with very few experimental resources and limited budgets that prevent the purchase of even basic laboratory equipment. For example, many high schools do not have the means of experimentally studying radioactivity because they lack Geiger counters and/or good radioactive sources. This was the case at the first high school one…

  7. Temporary Personal Radioactivity

    NASA Astrophysics Data System (ADS)

    Myers, Fred

    2012-11-01

    As part of a bone scan procedure to look for the spread of prostate cancer, I was injected with radioactive technetium. In an effort to occupy/distract my mind, I used a Geiger counter to determine if the radioactive count obeyed the inverse-square law as a sensor was moved away from my bladder by incremental distances.

  8. Understanding radioactive waste

    SciTech Connect

    Murray, R.L.

    1981-12-01

    This document contains information on all aspects of radioactive wastes. Facts are presented about radioactive wastes simply, clearly and in an unbiased manner which makes the information readily accessible to the interested public. The contents are as follows: questions and concerns about wastes; atoms and chemistry; radioactivity; kinds of radiation; biological effects of radiation; radiation standards and protection; fission and fission products; the Manhattan Project; defense and development; uses of isotopes and radiation; classification of wastes; spent fuels from nuclear reactors; storage of spent fuel; reprocessing, recycling, and resources; uranium mill tailings; low-level wastes; transportation; methods of handling high-level nuclear wastes; project salt vault; multiple barrier approach; research on waste isolation; legal requiremnts; the national waste management program; societal aspects of radioactive wastes; perspectives; glossary; appendix A (scientific American articles); appendix B (reference material on wastes). (ATT)

  9. Radioactive gold ring dermatitis

    SciTech Connect

    Miller, R.A.; Aldrich, J.E. )

    1990-08-01

    A superficial squamous cell carcinoma developed in a woman who wore a radioactive gold ring for more than 30 years. Only part of the ring was radioactive. Radiation dose measurements indicated that the dose to basal skin layer was 2.4 Gy (240 rad) per week. If it is assumed that the woman continually wore her wedding ring for 37 years since purchase, she would have received a maximum dose of approximately 4600 Gy.

  10. Container for radioactive materials

    DOEpatents

    Fields, Stanley R. (Richland, WA)

    1985-01-01

    A container for housing a plurality of canister assemblies containing radioactive material and disposed in a longitudinally spaced relation within a carrier to form a payload package concentrically mounted within the container. The payload package includes a spacer for each canister assembly, said spacer comprising a base member longitudinally spacing adjacent canister assemblies from each other and a sleeve surrounding the associated canister assembly for centering the same and conducting heat from the radioactive material in a desired flow path.

  11. Temporary Personal Radioactivity

    ERIC Educational Resources Information Center

    Myers, Fred

    2012-01-01

    As part of a bone scan procedure to look for the spread of prostate cancer, I was injected with radioactive technetium. In an effort to occupy/distract my mind, I used a Geiger counter to determine if the radioactive count obeyed the inverse-square law as a sensor was moved away from my bladder by incremental distances. (Contains 1 table and 2…

  12. Dynamic radioactive particle source

    SciTech Connect

    Moore, Murray E.; Gauss, Adam Benjamin; Justus, Alan Lawrence

    2012-06-26

    A method and apparatus for providing a timed, synchronized dynamic alpha or beta particle source for testing the response of continuous air monitors (CAMs) for airborne alpha or beta emitters is provided. The method includes providing a radioactive source; placing the radioactive source inside the detection volume of a CAM; and introducing an alpha or beta-emitting isotope while the CAM is in a normal functioning mode.

  13. Investigation of aerial dispersion of radioactive dust from an open-pit uranium mine by passive vinyl collectors.

    PubMed

    Pettersson, H B; Koperski, J

    1991-05-01

    Detailed investigations of the aerial dispersion of radioactive dust from the biggest open-pit U mining and milling operation in Australia were carried out. Spatial distributions of the long-lived radionuclides of 238U series and their origin, i.e., mining and milling operations vs. natural background radiation, have been studied. Horizontal flux, dry deposition, and ground resuspension of the radionuclides were investigated along a 50-km transect in the direction of the prevailing monsoonal winds in the region. The study was performed by means of unconventional "sticky vinyl" passive dust collectors, occasionally supported by high-volume air filter samplers. The data from the flux measurements show an inverse square to inverse cubic dependence, and the dry deposition exhibits an inverse square dependence, of radionuclide load vs. distance. The pit has been the predominant contributor of long-lived U series radionuclides to the environment within the radius of several kilometers from the operations. An aerial dispersion computer code (LUCIFER), based on a Gaussian plume model, was developed for the project. Experimental data were used as the code input data. Good agreement between the measured data and the normalized computed results was obtained. PMID:2019500

  14. Radioactivity in food crops

    SciTech Connect

    Drury, J.S.; Baldauf, M.F.; Daniel, E.W.; Fore, C.S.; Uziel, M.S.

    1983-05-01

    Published levels of radioactivity in food crops from 21 countries and 4 island chains of Oceania are listed. The tabulation includes more than 3000 examples of 100 different crops. Data are arranged alphabetically by food crop and geographical origin. The sampling date, nuclide measured, mean radioactivity, range of radioactivities, sample basis, number of samples analyzed, and bibliographic citation are given for each entry, when available. Analyses were reported most frequently for /sup 137/Cs, /sup 40/K, /sup 90/Sr, /sup 226/Ra, /sup 228/Ra, plutonium, uranium, total alpha, and total beta, but a few authors also reported data for /sup 241/Am, /sup 7/Be, /sup 60/Co, /sup 55/Fe, /sup 3/H, /sup 131/I, /sup 54/Mn, /sup 95/Nb, /sup 210/Pb, /sup 210/Po, /sup 106/Ru, /sup 125/Sb, /sup 228/Th, /sup 232/Th, and /sup 95/Zr. Based on the reported data it appears that radioactivity from alpha emitters in food crops is usually low, on the order of 0.1 Bq.g/sup -1/ (wet weight) or less. Reported values of beta radiation in a given crop generally appear to be several orders of magnitude greater than those of alpha emitters. The most striking aspect of the data is the great range of radioactivity reported for a given nuclide in similar food crops with different geographical origins.

  15. Radioactive Waste Management

    SciTech Connect

    Bales, J.D.; Graham, J.; Boshears, R.

    1996-01-01

    Radioactive Waste Management (RWM) announces on a monthly basis the current worldwide information available on the critical topics of spent-fuel transport and storage, radioactive effluents from nuclear facilities, techniques of processing radioactive wastes, their storage, and ultimate disposal. Information on remedial actions and other environmental aspects is also included. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database during the past month. Also included are other US information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency`s Energy Technology Data Exchange, the International Atomic Energy Agency`s International Nuclear Information System or government-to-government agreements.

  16. Radioactivity of Consumer Products

    NASA Astrophysics Data System (ADS)

    Peterson, David; Jokisch, Derek; Fulmer, Philip

    2006-11-01

    A variety of consumer products and household items contain varying amounts of radioactivity. Examples of these items include: FiestaWare and similar glazed china, salt substitute, bananas, brazil nuts, lantern mantles, smoke detectors and depression glass. Many of these items contain natural sources of radioactivity such as Uranium, Thorium, Radium and Potassium. A few contain man-made sources like Americium. This presentation will detail the sources and relative radioactivity of these items (including demonstrations). Further, measurements of the isotopic ratios of Uranium-235 and Uranium-238 in several pieces of china will be compared to historical uses of natural and depleted Uranium. Finally, the presenters will discuss radiation safety as it pertains to the use of these items.

  17. Container for radioactive materials

    DOEpatents

    Fields, S.R.

    1984-05-30

    A container is claimed for housing a plurality of canister assemblies containing radioactive material. The several canister assemblies are stacked in a longitudinally spaced relation within a carrier to form a payload concentrically mounted within the container. The payload package includes a spacer for each canister assembly, said spacer comprising a base member longitudinally spacing adjacent canister assemblies from each other and sleeve surrounding the associated canister assembly for centering the same and conducting heat from the radioactive material in a desired flow path. 7 figures.

  18. Numerical dating of a Late Quaternary spit-shoreline complex at the northern end of Silver Lake playa, Mojave Desert, California: A comparison of the applicability of radiocarbon, luminescence, terrestrial cosmogenic nuclide, electron spin resonance, U-series and amino acid racemization methods

    USGS Publications Warehouse

    Owen, L.A.; Bright, Jordon; Finkel, R.C.; Jaiswal, M.K.; Kaufman, D.S.; Mahan, S.; Radtke, U.; Schneider, J.S.; Sharp, W.; Singhvi, A.K.; Warren, C.N.

    2007-01-01

    A Late Quaternary spit-shoreline complex on the northern shore of Pleistocene Lake Mojave of southeastern California, USA was studied with the goal of comparing accelerator mass spectrometry (AMS) radiocarbon, luminescence, electron spin resonance (ESR), terrestrial cosmogenic radionuclide (TCN) surface exposure, amino acid racemization (AAR) and U-series dating methods. The pattern of ages obtained by the different methods illustrates the complexity of processes acting in the lakeshore environment and highlights the utility of a multi-method approach. TCN surface exposure ages (mostly ???20-30 ka) record the initial erosion of shoreline benches, whereas radiocarbon ages on shells (determined in this and previous studies) within the spit, supported by AAR data, record its construction at fluctuating lake levels from ???16 to 10 ka. Luminescence ages on spit sediment (???6-7 ka) and ESR ages on spit shells (???4 ka) are anomalously young relative to radiocarbon ages of shells within the same deposits. The significance of the surprisingly young luminescence ages is not clear. The younger ESR ages could be a consequence of post-mortem enrichment of U in the shells. High concentrations of detrital thorium in tufa coating spit gravels inhibited the use of single-sample U-series dating. Detailed comparisons such as this provide one of the few means of assessing the accuracy of Quaternary dating techniques. More such comparisons are needed. ?? 2007 Elsevier Ltd and INQUA.

  19. TABLE OF RADIOACTIVE ELEMENTS.

    SciTech Connect

    HOLDEN,N.E.

    2001-06-29

    For those chemical elements which have no stable nuclides with a terrestrial isotopic composition, the data on radioactive half-lives and relative atomic masses for the nuclides of interest and importance have been evaluated and the recommended values and uncertainties are listed.

  20. Radioactivity and foods

    SciTech Connect

    Olszyna-Marzys, A.E. )

    1991-01-01

    The purpose of this article is to describe and contrast two relationships between radiation and food--on the one hand, beneficial preservation of food by controlled exposure to ionizing radiation; and, on the other, contamination of food by accidental incorporation of radioactive nuclides within the food itself. In food irradiation, electrons or electromagnetic radiation is used to destroy microorganisms and insects or prevent seed germination. The economic advantages and health benefits of sterilizing food in this manner are clear, and numerous studies have confirmed that under strictly controlled conditions no undersirable changes or induced radioactivity is produced in the irradiated food. An altogether different situation is presented by exposure of food animals and farming areas to radioactive materials, as occurred after the major Soviet nuclear reactor accident at Chenobyl. This article furnishes the basic information needed to understand the nature of food contamination associated with that event and describes the work of international organizations seeking to establish appropriate safe limits for levels of radioactivity in foods.

  1. Viewer Makes Radioactivity "Visible"

    NASA Technical Reports Server (NTRS)

    Yin, L. I.

    1983-01-01

    Battery operated viewer demonstrates feasibility of generating threedimensional visible light simulations of objects that emit X-ray or gamma rays. Ray paths are traced for two pinhold positions to show location of reconstructed image. Images formed by pinholes are converted to intensified visible-light images. Applications range from radioactivity contamination surveys to monitoring radioisotope absorption in tumors.

  2. Radioactivity: A Natural Phenomenon.

    ERIC Educational Resources Information Center

    Ronneau, C.

    1990-01-01

    Discussed is misinformation people have on the subject of radiation. The importance of comparing artificial source levels of radiation to natural levels is emphasized. Measurements of radioactivity, its consequences, and comparisons between the risks induced by radiation in the environment and from artificial sources are included. (KR)

  3. Radioactive Decay - An Analog.

    ERIC Educational Resources Information Center

    McGeachy, Frank

    1988-01-01

    Presents an analog of radioactive decay that allows the student to grasp the concept of half life and the exponential nature of the decay process. The analog is devised to use small, colored, plastic poker chips or counters. Provides the typical data and a graph which supports the analog. (YP)

  4. Consumer Products Containing Radioactive Materials

    MedlinePLUS

    ... Materials Everything we encounter in our daily lives contains some radioactive material, some naturally occurring and some ... products. In- cluded are the items that can contain sufficient radioactive material to be distinguished from the ...

  5. Environmental Radioactivity, Temperature, and Precipitation.

    ERIC Educational Resources Information Center

    Riland, Carson A.

    1996-01-01

    Reports that environmental radioactivity levels vary with temperature and precipitation and these effects are due to radon. Discusses the measurement of this environmental radioactivity and the theory behind it. (JRH)

  6. Natural radioactivity and radiological hazards assessment of bone-coal from a vanadium mine in central China

    NASA Astrophysics Data System (ADS)

    Huang, Yan-Jun; Chen, Chao-Feng; Huang, Yi-Chao; Yue, Qi-Jian; Zhong, Chun-Ming; Tan, Cheng-Jun

    2015-02-01

    A comprehensive utilization project of bone-coal in a vanadium mine was proposing in recent years in central China. Based on the analysis of 31 representative bone-coal samples from 9 boreholes at various depth drilled in planning initial minery, the average activity concentrations of 238U, 226Ra, 232Th and 40K were determined in the range of 196.4-653.3 Bq/kg, 200.2-564.4 Bq/kg, 9.4-64.6 Bq/kg and 71.5-345.4 Bq/kg, respectively. The major natural radionuclides were identified as U-series nuclides with the activity concentrations obviously higher than common coal. The estimated absorbed dose rates in the air varied between 107.1 and 310.5 nGy/h. The averaged external annual effective dose due to the radioactivity in the bone-coal was predicted as 0.37 mSv/a, and the main contribution is 87.5% for U-series. The radium equivalent activity, the external and internal indices of most of the samples were shown with high values of an unacceptable level, which indicated the bone-coal would carry a considerable radiation hazard to the workers and the local individuals. The hazard of radon inhalation should be focused during mining and following processes. Further radiological assessment should be carried out as the natural radioactivity in the bone-coal would be technically enriched during the combustion process of the bone-coal and utilization of the byproducts.

  7. Sources of radioactive ions

    SciTech Connect

    Alonso, J.R.

    1985-05-01

    Beams of unstable nuclei can be formed by direct injection of the radioactive atoms into an ion source, or by using the momentum of the primary production beam as the basis for the secondary beam. The effectiveness of this latter mechanism in secondary beam formation, i.e., the quality of the emerging beam (emittance, intensity, energy spread), depends critically on the nuclear reaction kinematics, and on the magnitude of the incident beam energy. When this beam energy significantly exceeds the energies typical of the nuclear reaction process, many of the qualities of the incident beam can be passed on to the secondary beam. Factors affecting secondary beam quality are discussed, along with techniques for isolating and purifying a specific secondary product. The ongoing radioactive beam program at the Bevalac is used as an example, with applications, present performance and plans for improvements.

  8. Hanford's radioactive tumbleweed

    SciTech Connect

    Marshall, E.

    1987-06-26

    The Department of Energy has not yet settled on a plan for dealing with the extensive ground contamination at Hanford. After 44 years of storing radioactive wastes on site, DOE's temporary measures begin to look permanent; cleanup would cost billions of dollars. Radioactive wastes have been emptied into steel tanks, earthen ditches, trenches, cribs, ponds, swamps, underground drains, and deep wells. Long-lived transuranic wastes have also been buried in boxes or drums that will soon corrode. Burrowing animals and tumbleweed, with roots that can grow 20 feet, are spreading the contamination. Tumbleweed roots reach down into waste dumps and take up strontium-90, break off, and blow around the dry land. There is a major concern that they will build up in the environment, and if there is a range fire, they may produce airborne contamination. There is also a chance that they could blow to the river and contaminate the water.

  9. Radiations from Radioactive Substances

    NASA Astrophysics Data System (ADS)

    Rutherford, Ernest; Chadwick, James; Drummond Ellis, Charles

    2010-06-01

    Preface; 1. Radioactive transformations; 2. The alpha rays; 3. Absorption of the alpha rays; 4. Some properties of the alpha particle; 5. Theories of absorption of alpha rays; 6. Secondary effects produced by alpha rays; 7. General properties of the radiations; 8. The scattering of alpha and beta particles; 9. The collisions of alpha particles with light atoms; 10. The artificial disintegration of the light elements; 11. The radioactive nuclei; 12. Beta ray and gamma ray spectra; 13. The disintegration electrons; 14. The passage of beta particles through matter; 15. The scattering and absorption of gamma rays; 16. Intensity problems connected with the emission of gamma rays; 17. Atomic nuclei; 18. Miscellaneous; Appendix; Indexes.

  10. Radioactive ion detector

    DOEpatents

    Bower, K.E.; Weeks, D.R.

    1997-08-12

    Apparatus for detecting the presence, in aqueous media, of substances which emit alpha and/or beta radiation and determining the oxidation state of these radioactive substances, that is, whether they are in cationic or anionic form. In one embodiment, a sensor assembly has two elements, one comprised of an ion-exchange material which binds cations and the other comprised of an ion-exchange material which binds anions. Each ion-exchange element is further comprised of a scintillation plastic and a photocurrent generator. When a radioactive substance to which the sensor is exposed binds to either element and emits alpha or beta particles, photons produced in the scintillation plastic illuminate the photocurrent generator of that element. Sensing apparatus senses generator output and thereby indicates whether cationic species or anionic species or both are present and also provides an indication of species quantity. 2 figs.

  11. Radioactive ion detector

    DOEpatents

    Bower, Kenneth E. (Los Alamos, NM); Weeks, Donald R. (Saratoga, CA)

    1997-01-01

    Apparatus for detecting the presence, in aqueous media, of substances which emit alpha and/or beta radiation and determining the oxidation state of these radioactive substances, that is, whether they are in cationic or anionic form. In one embodiment, a sensor assembly has two elements, one comprised of an ion-exchange material which binds cations and the other comprised of an ion-exchange material which binds anions. Each ion-exchange element is further comprised of a scintillation plastic and a photocurrent generator. When a radioactive substance to which the sensor is exposed binds to either element and emits alpha or beta particles, photons produced in the scintillation plastic illuminate the photocurrent generator of that element. Sensing apparatus senses generator output and thereby indicates whether cationic species or anionic species or both are present and also provides an indication of species quantity.

  12. Natural radioactivity levels in mineral, therapeutic and spring waters in Tunisia

    NASA Astrophysics Data System (ADS)

    Labidi, S.; Mahjoubi, H.; Essafi, F.; Ben Salah, R.

    2010-12-01

    Radioactivity measurements were carried out in 26 groundwater samples from Tunisia. Activity concentrations of uranium were studied by radiochemical separation procedures followed by alpha spectrometry and that for radium isotopes by gamma-ray spectrometry. The results show that, the concentrations in water samples range from 1.2 to 69 mBq/L.1, 1.3 to 153.4 mBq/L, 2.0 to 1630.0 mBq/L and 2.0 to 1032.0 mBq/L for 238U, 234U, 226Ra and 228Ra, respectively. The U and Ra activity concentrations are low and similar to those published for other regions in the world. The natural radioactivity levels in the investigated samples are generally increased from mineral waters through therapeutic to the spring waters. The results show that a correlation between total dissolved solids (TDS) values and the 226Ra concentrations was found to be high indicating that 266Ra has a high affinity towards the majority of mineral elements dissolved in these waters. High correlation coefficients were also observed between 226Ra content and chloride ions for Cl --Na + water types. This can be explained by the fact that radium forms a complex with chloride and in this form is more soluble. The isotopic ratio of 234U/ 238U and 226Ra/ 234U varies in the range from 0.8 to 2.6 and 0.6 to 360.8, respectively, in all investigated waters, which means that there is no radioactive equilibrium between the two members of the 238U series. The fractionation of isotopes of a given element may occur because of preferential leaching of one, or by the direct action of recoil during radioactive decay. The annual effective doses due to ingestion of the mineral waters have been estimated to be well below the 0.1 mSv/y reference dose level.

  13. Table of radioactive elements

    SciTech Connect

    Holden, N.E.

    1985-01-01

    As has been the custom in the past, the Commission publishes a table of relative atomic masses and halflives of selected radionuclides. The information contained in this table will enable the user to calculate the atomic weight for radioactive materials with a variety of isotopic compositions. The atomic masses have been taken from the 1984 Atomic Mass Table. Some of the halflives have already been documented.

  14. PROCESSING OF RADIOACTIVE WASTE

    DOEpatents

    Johnson, B.M. Jr.; Barton, G.B.

    1961-11-14

    A process for treating radioactive waste solutions prior to disposal is described. A water-soluble phosphate, borate, and/or silicate is added. The solution is sprayed with steam into a space heated from 325 to 400 deg C whereby a powder is formed. The powder is melted and calcined at from 800 to 1000 deg C. Water vapor and gaseous products are separated from the glass formed. (AEC)

  15. Radioactive waste storage issues

    SciTech Connect

    Kunz, D.E.

    1994-08-15

    In the United States we generate greater than 500 million tons of toxic waste per year which pose a threat to human health and the environment. Some of the most toxic of these wastes are those that are radioactively contaminated. This thesis explores the need for permanent disposal facilities to isolate radioactive waste materials that are being stored temporarily, and therefore potentially unsafely, at generating facilities. Because of current controversies involving the interstate transfer of toxic waste, more states are restricting the flow of wastes into - their borders with the resultant outcome of requiring the management (storage and disposal) of wastes generated solely within a state`s boundary to remain there. The purpose of this project is to study nuclear waste storage issues and public perceptions of this important matter. Temporary storage at generating facilities is a cause for safety concerns and underscores, the need for the opening of permanent disposal sites. Political controversies and public concern are forcing states to look within their own borders to find solutions to this difficult problem. Permanent disposal or retrievable storage for radioactive waste may become a necessity in the near future in Colorado. Suitable areas that could support - a nuclear storage/disposal site need to be explored to make certain the health, safety and environment of our citizens now, and that of future generations, will be protected.

  16. ASSESSMENT OF RADIOACTIVE AND NON-RADIOACTIVE CONTAMINANTS FOUND IN LOW LEVEL RADIOACTIVE WASTE STREAMS

    SciTech Connect

    R.H. Little, P.R. Maul, J.S.S. Penfoldag

    2003-02-27

    This paper describes and presents the findings from two studies undertaken for the European Commission to assess the long-term impact upon the environment and human health of non-radioactive contaminants found in various low level radioactive waste streams. The initial study investigated the application of safety assessment approaches developed for radioactive contaminants to the assessment of nonradioactive contaminants in low level radioactive waste. It demonstrated how disposal limits could be derived for a range of non-radioactive contaminants and generic disposal facilities. The follow-up study used the same approach but undertook more detailed, disposal system specific calculations, assessing the impacts of both the non-radioactive and radioactive contaminants. The calculations undertaken indicated that it is prudent to consider non-radioactive, as well as radioactive contaminants, when assessing the impacts of low level radioactive waste disposal. For some waste streams with relatively low concentrations of radionuclides, the potential post-closure disposal impacts from non-radioactive contaminants can be comparable with the potential radiological impacts. For such waste streams there is therefore an added incentive to explore options for recycling the materials involved wherever possible.

  17. RADIOACTIVE MATERIALS SENSORS

    SciTech Connect

    Mayo, Robert M.; Stephens, Daniel L.

    2009-09-15

    Providing technical means to detect, prevent, and reverse the threat of potential illicit use of radiological or nuclear materials is among the greatest challenges facing contemporary science and technology. In this short article, we provide brief description and overview of the state-of-the-art in sensor development for the detection of radioactive materials, as well as an identification of the technical needs and challenges faced by the detection community. We begin with a discussion of gamma-ray and neutron detectors and spectrometers, followed by a description of imaging sensors, active interrogation, and materials development, before closing with a brief discussion of the unique challenges posed in fielding sensor systems.

  18. Radioactive waste material disposal

    DOEpatents

    Forsberg, Charles W. (155 Newport Dr., Oak Ridge, TN 37830); Beahm, Edward C. (106 Cooper Cir., Oak Ridge, TN 37830); Parker, George W. (321 Dominion Cir., Knoxville, TN 37922)

    1995-01-01

    The invention is a process for direct conversion of solid radioactive waste, particularly spent nuclear fuel and its cladding, if any, into a solidified waste glass. A sacrificial metal oxide, dissolved in a glass bath, is used to oxidize elemental metal and any carbon values present in the waste as they are fed to the bath. Two different modes of operation are possible, depending on the sacrificial metal oxide employed. In the first mode, a regenerable sacrificial oxide, e.g., PbO, is employed, while the second mode features use of disposable oxides such as ferric oxide.

  19. Simpler radioactive wastewater processing.

    PubMed

    Rodrguez, Jos Canga; Luh, Volker

    2011-11-01

    Jos Canga Rodrguez, key account manager, Pharmaceutical and Life Sciences, EnviroChemie, and Volker Luh, CEO of EnviroDTS, describe the development, and recent successful application, of a new technology for dealing safely and effectively with the radioactive "wastewater" generated by patients who have undergone radiotherapy in nuclear medicine facilities. The BioChroma process provides what is reportedly not only a more flexible means than traditional "delay and decay" systems of dealing with this "by-product" of medical treatment, but also one that requires less plant space, affords less risk of leakage or cross-contamination, and is easier to install. PMID:22368885

  20. Radioactive waste material disposal

    DOEpatents

    Forsberg, C.W.; Beahm, E.C.; Parker, G.W.

    1995-10-24

    The invention is a process for direct conversion of solid radioactive waste, particularly spent nuclear fuel and its cladding, if any, into a solidified waste glass. A sacrificial metal oxide, dissolved in a glass bath, is used to oxidize elemental metal and any carbon values present in the waste as they are fed to the bath. Two different modes of operation are possible, depending on the sacrificial metal oxide employed. In the first mode, a regenerable sacrificial oxide, e.g., PbO, is employed, while the second mode features use of disposable oxides such as ferric oxide. 3 figs.

  1. Radioactive and magnetic investigations

    NASA Technical Reports Server (NTRS)

    Heye, D.; Beiersdorf, H.

    1979-01-01

    Age and growth pattern determination of manganese nodules were explored. Two methods are discussed: (1) measurement of the presence of radioactive iodine isotopes; which is effective only up to 3.105 years, and (2) measurements of magnetism. The growth rates of three nodules were determined. The surface of the nodule was recent, and the overall age of the nodule could be determined with accuracy of better than 30%. Measurement of paleomagnetic effect was attempted to determine wider age ranges, however, the measured sign changes could not be interpreted as paleomagnetic reversals.

  2. Levels of radioactivity in Qatar

    SciTech Connect

    Al-Thani, A.A.; Abdul-Majid, S.; Mohammed, K.

    1995-12-31

    The levels of natural and man-made radioactivity in soil and seabed were measured in Qatar to assess radiation exposure levels and to evaluate any radioactive contamination that may have reached the country from fallout or due to the Chernobyl accident radioactivity release. Qatar peninsula is located on the Arabian Gulf, 4500 km from Chernobyl, and has an area of {approximately}11,600 km{sup 2} and a population of {approximately}600,000.

  3. Radioactive waste processing apparatus

    DOEpatents

    Nelson, Robert E. (Lombard, IL); Ziegler, Anton A. (Darien, IL); Serino, David F. (Maplewood, MN); Basnar, Paul J. (Western Springs, IL)

    1987-01-01

    Apparatus for use in processing radioactive waste materials for shipment and storage in solid form in a container is disclosed. The container includes a top, and an opening in the top which is smaller than the outer circumference of the container. The apparatus includes an enclosure into which the container is placed, solution feed apparatus for adding a solution containing radioactive waste materials into the container through the container opening, and at least one rotatable blade for blending the solution with a fixing agent such as cement or the like as the solution is added into the container. The blade is constructed so that it can pass through the opening in the top of the container. The rotational axis of the blade is displaced from the center of the blade so that after the blade passes through the opening, the blade and container can be adjusted so that one edge of the blade is adjacent the cylindrical wall of the container, to insure thorough mixing. When the blade is inside the container, a substantially sealed chamber is formed to contain vapors created by the chemical action of the waste solution and fixant, and vapors emanating through the opening in the container.

  4. Stefan Meyer: Pioneer of Radioactivity

    NASA Astrophysics Data System (ADS)

    Reiter, Wolfgang L.

    2001-03-01

    Stefan Meyer was one of the pioneers in radioactivity research and director of the Vienna Radium Institute, the first institution in the world devoted exclusively to radioactivity. I give here a biographical sketch of Meyer and of some of his colleagues and an overview of the research activities at the Radium Institute.

  5. Understanding radioactive waste. Fourth edition

    SciTech Connect

    Murray, R.L.

    1994-12-31

    Understanding Radioactive Waste has proven to be an informative and valuable textbook for high school and college students as well as an excellent reference for concerned citizens. Now in its fourth edition, it explains what radioactivity is and goes on to explore the merits of various methods of disposal and the use of licensing and regulation as forms of protection.

  6. Radioactive elements in stellar atmospheres

    SciTech Connect

    Gopka, Vira; Yushchenko, Alexander; Goriely, Stephane; Shavrina, Angelina; Kang, Young Woon

    2006-07-12

    The identification of lines of radioactive elements (Tc, Pm and elements with 83radioactive decay of Th and U in the upper levels of stellar atmospheres, contamination of stellar atmosphere by recent SN explosion, and spallation reactions.

  7. Low Radioactivity in CANDLES

    SciTech Connect

    Kishimoto, T.; Ogawa, I.; Hazama, R.; Yoshida, S.; Umehara, S.; Matsuoka, K.; Sakai, H.; Yokoyama, D.; Mukaida, K.; Ichihara, K.; Tatewaki, Y.; Kishimoto, K.; Hirano, Y.; Yanagisawa, A.; Ajimura, S.

    2005-09-08

    CANDLES is the project to search for double beta decay of 48Ca by using CaF2 crystals. Double beta decay of 48Ca has the highest Q value among all nuclei whose double beta decay is energetically allowed. This feature makes the study almost background free and becomes important once the study is limited by the backgrounds. We studied double beta decays of 48Ca by using ELEGANTS VI detector system which features CaF2(Eu) crystals. We gave the best limit on the lifetime of neutrino-less double beta decay of 48Ca although further development is vital to reach the neutrino mass of current interest for which CANDLES is designed. In this article we present how CANDLES can achieve low radioactivity, which is the key for the future double beta decay experiment.

  8. PERSPECTIVE: Fireworks and radioactivity

    NASA Astrophysics Data System (ADS)

    Breitenecker, Katharina

    2009-09-01

    Katharina Breitenecker Fireworks, the one and only amongst all other pyrotechnic applications, have pleased the hearts and minds of billions of people all over the world for almost 1000 years. Even though pyrotechnics were originally developed in order to fulfil the needs of military purposes, fireworks began to form a unique part of the cultural heritage of many countries, presumably starting in ancient China during the Song Dynasty (960-1280 AD). Festivities like New Year's Eve, national holidays or activities like music festivals and parish fairs are crowned by a firework display. Fireworks have traditionally been associated with Independence Day celebrations, like 4 July in the United States, Guy Fawkes' Night (5 November) in Britain, or Bastille Day (14 July) in France. Much of Chinese culture is associated with the use of firecrackers to celebrate the New Year and other important occasions. The fascination of fireworks and firecrackers is due to the brilliant colours and booming noises, which have a universal appeal to our basic senses [1]. The basic components of any traditional civil firework is black powder, a mixture of about 75% potassium nitrate, 15% charcoal, and about 10% sulfur [2]. Without the addition of a colouring agent, the fuel would provide an almost white light. Therefore, several metal salts can be added to cause colourful luminescence upon combustion. In general barium is used to obtain a green coloured flame, strontium for red, copper for blue and sodium for yellow [2, 3]. The use of pyrotechnics has raised issues pertaining to health concerns. The health aspects are not only restricted to injuries by accidental ignition of certain devices. Moreover, several recent works identified fireworks and pyrotechnics as causing environmental pollution, which might result in a potential hazard concerning health aspects. The fundamental problem in this respect is that all chemicals used are dispersed in the environment by combustion. This includes both reaction products and unburnt constituents of a pyrotechnic mixture. One major environmental concern in pyrotechnics focuses on the emission of heavy metals. This is the topic discussed in the article by Georg Steinhauser and Andreas Musilek in this issue [4]. A possible interrelationship between respiratory effects and fireworks emissions of barium-rich aerosols was also raised last year [5]. In recent years the potential hazard of naturally occurring radioactive material has become of importance to the scientific community. Naturally occurring radionuclides can be of terrestrial or cosmological origin. Terrestrial radionuclides were present in the presolar cloud that later contracted in order to build our solar system. These radionuclides—mainly heavy metals—and their non-radioactive isotopes are nowadays fixed in the matrix of the Earth's structure. Usually, their percentage is quite small compared to their respective stable isotopes—though there are exceptions like in the case of radium. The problem with environmental pollution due to naturally occurring radioactive material begins when this material is concentrated due to mining and milling, and later further processed [6]. Environmental pollution due to radioactive material goes back as far as the Copper and Iron Ages, when the first mines were erected in order to mine ores (gold, silver, copper, iron, etc), resulting in naturally occurring radioactive material being set free with other dusts into the atmosphere. So where is the link between pyrotechnics and radioactivity? In this article presented by Georg Steinhauser and Andreas Musilek [4], the pyrotechnic ingredients barium nitrate and strontium nitrate are explored with respect to their chemical similarities to radium. The fundamental question, therefore, was whether radium can be processed together with barium and strontium. If so, the production and ignition of these pyrotechnic ingredients could cause atmospheric pollution with radium aerosols, resulting in potential negative health effects, unless an extensive purification of the ores is undertaken. From the environmental and toxicological point of view, the formation of barium-rich aerosols following the display of fireworks is a problem. The barium compounds released are mainly in a bioavailable form. Considering the chemical similarities of barium and strontium to radium, the potential hazard of fireworks due to liberated radionuclides might be of interest. Ores and compounds used for pyrotechnic devices are usually purified only to the grade that is necessary for the intended effect. Thus, fireworks can contain traces of heavy metals which do not have a pyrotechnic function [5, 7, 8]. The incorporation, and thus, the inhalation of α-emitters (such as 226Ra) is a major health issue in human radiation protection. In order to examine the potential hazard Georg Steinhauser and Andreas Musilek investigated this topic. Although the specific radium activities were relatively low in the investigated samples, Steinhauser and Musilek showed that radium is significantly enriched in pyrotechnics. This fact gives no reason why people should not attend firework displays or should not set off their own fireworks on New Year's Eve. Rather, it is now the authorities' turn to take care of this topic. What if highly active radiobarite was used as a raw material for the production of pyrotechnic indoor devices? This would definitely cause unexpected health issues. Now that the problem is identified, the authorities have to ensure that the exemption limits are not exceeded. Today, public opinion is going more and more in the direction of using eco-friendly products. A lot of products have been shown to have potential negative health effects and are therefore now produced in safer and more eco-friendly forms than they used to be a few years ago. Thus, Georg Steinhauser and Andreas Musilek demonstrated that pyrotechnics do contain a certain amount of radioactive material—so why not make pyrotechnics safer, more eco-friendly and 'greener'? References [1] Plimpton G 1984 Fireworks: A History and Celebration (New York: Doubleday) [2] Russell M S 2000 The Chemistry of Fireworks (Cambridge: Royal Society of Chemistry) [3] Steinhauser G and Klapötke T M 2008 'Green' pyrotechnics: a chemist's challenge Angew. Chem. Int. Ed. 47 3330-47 [4] Steinhauser G and Musilek A 2009 Do pyrotechnics contain radium? Environ. Res. Lett. 4 034006 [5] Steinhauser G, Sterba J H, Foster M, Grass F and Bichler M 2008 Heavy metals from pyrotechnics in New Year's Eve snow Atmos. Environ. 42 8616-22 [6] Cooper J R, Randle K and Sokhi R S 2003 Radioactive Releases in the Environment—Impact and Assessment (Chichester: Wiley) [7] Smith R M and Dinh V-D 1975 Changes in forced expiration flow due to air pollution from fireworks Environ. Res. 9 321-31 [8] Bach W, Dickinson L, Weiner B and Costello G 1972 Some adverse health effects due to air pollution from fireworks Hawaii Med. J. 31 459-65

  9. Radioactive waste processing apparatus

    DOEpatents

    Nelson, R.E.; Ziegler, A.A.; Serino, D.F.; Basnar, P.J.

    1985-08-30

    Apparatus for use in processing radioactive waste materials for shipment and storage in solid form in a container is disclosed. The container includes a top, and an opening in the top which is smaller than the outer circumference of the container. The apparatus includes an enclosure into which the container is placed, solution feed apparatus for adding a solution containing radioactive waste materials into the container through the container opening, and at least one rotatable blade for blending the solution with a fixing agent such as cement or the like as the solution is added into the container. The blade is constructed so that it can pass through the opening in the top of the container. The rotational axis of the blade is displaced from the center of the blade so that after the blade passes through the opening, the blade and container can be adjusted so that one edge of the blade is adjacent the cylindrical wall of the container, to insure thorough mixing. When the blade is inside the container, a substantially sealed chamber is formed to contain vapors created by the chemical action of the waste solution and fixant, and vapors emanating through the opening in the container. The chamber may be formed by placing a removable extension over the top of the container. The extension communicates with the apparatus so that such vapors are contained within the container, extension and solution feed apparatus. A portion of the chamber includes coolant which condenses the vapors. The resulting condensate is returned to the container by the force of gravity.

  10. Star formation and extinct radioactivities

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.

    1984-01-01

    An assessment is made of the evidence for the existence of now-extinct radioactivities in primitive solar system material, giving attention to implications for the early stages of sun and solar system formation. The characteristics of possible disturbances in dense molecular clouds which can initiate the formation of cloud cores is discussed, with emphasis on these disturbances able to generate fresh radioactivities. A one-solar mass red giant star on the asymptotic giant branch appears to have been the best candidate to account for the short-lived extinct radioactivities in the early solar system.

  11. Beijing Radioactive Nuclear Beam Facility

    NASA Astrophysics Data System (ADS)

    Fan, Mingwu

    1997-05-01

    Beijing Radioactive Nuclear Beam Facility (BRNBF) is an ISOL type radioactive nuclear beam facility. A 70 MeV cyclotron with high intensity minus H beam will be adopted for the production of radioactive nuclei, which will then be isotopically separated by an on-line mass separator and then injected into an existing HI-13 tandem accelerator. A superconductive heavy ion linac will be used as post-accelerator. Then, high intensity and high resolution RNB of A up to 140 can be obtained with energy above the Coulomb barrier.

  12. Radioactive Waste Management

    NASA Astrophysics Data System (ADS)

    Baisden, P. A.; Atkins-Duffin, C. E.

    Issues related to the management of radioactive wastes are presented with specific emphasis on high-level wastes generated as a result of energy and materials production using nuclear reactors. The final disposition of these high-level wastes depends on which nuclear fuel cycle is pursued, and range from once-through burning of fuel in a light water reactor followed by direct disposal in a geologic repository to more advanced fuel cycles (AFCs) where the spent fuel is reprocessed or partitioned to recover the fissile material (primarily 235U and 239Pu) as well as the minor actinides (MAs) (neptunium, americium, and curium) and some long-lived fission products (e.g., 99Tc and 129I). In the latter fuel cycle, the fissile materials are recycled through a reactor to produce more energy, the short-lived fission products are vitrified and disposed of in a geologic repository, and the minor actinides and long-lived fission products are converted to less radiotoxic or otherwise stable nuclides by a process called transmutation. The advantages and disadvantages of the various fuel cycle options and the challenges to the management of nuclear wastes they represent are discussed.

  13. Radioactive decay data tables

    SciTech Connect

    Kocher, D.C.

    1981-01-01

    The estimation of radiation dose to man from either external or internal exposure to radionuclides requires a knowledge of the energies and intensities of the atomic and nuclear radiations emitted during the radioactive decay process. The availability of evaluated decay data for the large number of radionuclides of interest is thus of fundamental importance for radiation dosimetry. This handbook contains a compilation of decay data for approximately 500 radionuclides. These data constitute an evaluated data file constructed for use in the radiological assessment activities of the Technology Assessments Section of the Health and Safety Research Division at Oak Ridge National Laboratory. The radionuclides selected for this handbook include those occurring naturally in the environment, those of potential importance in routine or accidental releases from the nuclear fuel cycle, those of current interest in nuclear medicine and fusion reactor technology, and some of those of interest to Committee 2 of the International Commission on Radiological Protection for the estimation of annual limits on intake via inhalation and ingestion for occupationally exposed individuals.

  14. Radioactive waste material melter apparatus

    DOEpatents

    Newman, D.F.; Ross, W.A.

    1990-04-24

    An apparatus for preparing metallic radioactive waste material for storage is disclosed. The radioactive waste material is placed in a radiation shielded enclosure. The waste material is then melted with a plasma torch and cast into a plurality of successive horizontal layers in a mold to form a radioactive ingot in the shape of a spent nuclear fuel rod storage canister. The apparatus comprises a radiation shielded enclosure having an opening adapted for receiving a conventional transfer cask within which radioactive waste material is transferred to the apparatus. A plasma torch is mounted within the enclosure. A mold is also received within the enclosure for receiving the melted waste material and cooling it to form an ingot. The enclosure is preferably constructed in at least two parts to enable easy transport of the apparatus from one nuclear site to another. 8 figs.

  15. Radioactive waste material melter apparatus

    DOEpatents

    Newman, Darrell F. (Richland, WA); Ross, Wayne A. (Richland, WA)

    1990-01-01

    An apparatus for preparing metallic radioactive waste material for storage is disclosed. The radioactive waste material is placed in a radiation shielded enclosure. The waste material is then melted with a plasma torch and cast into a plurality of successive horizontal layers in a mold to form a radioactive ingot in the shape of a spent nuclear fuel rod storage canister. The apparatus comprises a radiation shielded enclosure having an opening adapted for receiving a conventional transfer cask within which radioactive waste material is transferred to the apparatus. A plasma torch is mounted within the enclosure. A mold is also received within the enclosure for receiving the melted waste material and cooling it to form an ingot. The enclosure is preferably constructed in at least two parts to enable easy transport of the apparatus from one nuclear site to another.

  16. Radioactivity of the Cooling Water

    DOE R&D Accomplishments Database

    Wigner, E. P.

    1943-03-01

    The most important source of radioactivity at the exit manifold of the pile will be due to O{sup 19}, formed by neutron absorption of O{sup 18}. A recent measurement of Fermi and Weil permits to estimate that it will be safe to stay about 80 minutes daily close to the exit manifolds without any shield. Estimates are given for the radioactivities from other sources both in the neighborhood and farther away from the pile.

  17. Storage depot for radioactive material

    DOEpatents

    Szulinski, Milton J.

    1983-01-01

    Vertical drilling of cylindrical holes in the soil, and the lining of such holes, provides storage vaults called caissons. A guarded depot is provided with a plurality of such caissons covered by shielded closures preventing radiation from penetrating through any linear gap to the atmosphere. The heat generated by the radioactive material is dissipated through the vertical liner of the well into the adjacent soil and thus to the ground surface so that most of the heat from the radioactive material is dissipated into the atmosphere in a manner involving no significant amount of biologically harmful radiation. The passive cooling of the radioactive material without reliance upon pumps, personnel, or other factor which might fail, constitutes one of the most advantageous features of this system. Moreover this system is resistant to damage from tornadoes or earthquakes. Hermetically sealed containers of radioactive material may be positioned in the caissons. Loading vehicles can travel throughout the depot to permit great flexibility of loading and unloading radioactive materials. Radioactive material can be shifted to a more closely spaced caisson after ageing sufficiently to generate much less heat. The quantity of material stored in a caisson is restricted by the average capacity for heat dissipation of the soil adjacent such caisson.

  18. Endangered and Extinct Radioactivity

    NASA Astrophysics Data System (ADS)

    Leising, M. D.

    1993-07-01

    Gamma ray spectroscopy holds great promise for probing nucleosynthesis in individual nucleosynthesis events, via observations of short-lived radioactivity, and for measuring global galactic nucleosynthesis today with detections of longer-lived radioactivity. Many of the astrophysical issues addressed by these observations are precisely those that must be understood in order to interpret observations of extinct radioactivity in meteorites. It was somewhat surprising that the former case was realized first for a Type II supernova, when both 56Co [1] and 57Co [2] were detected in SN 1987A. These provide unprecedented constraints on models of Type II explosions. Live 26Al in the galaxy might come from Type II supernovae and their progenitors, and if this is eventually shown to be the case, can constrain massive star evolution, supernova nucleosynthesis, the galactic Type II supernova rate, and even models of the chemical evolution of the galaxy [3]. Titanium-44 is produced primarily in the alpha-rich freezeout from nuclear statistical equilibrium, possibly in Type Ia [4] and almost certainly in Type II supernovae [5]. The galactic recurrence time of these events is comparable to the 44Ti lifetime, so we expect to be able to see at most a few otherwise unseen 44Ti remnants at any given time. No such remnants have been detected yet [6]. Very simple arguments lead to the expectation that about 4 x 10^-4 M(sub)solar mass of 44Ca are produced per century. The product of the supernova frequency times the 44Ti yield per event must equal this number. Even assuming that only the latest event would be seen, rates in excess of 2 century^-1 are ruled out at >=99% confidence by the gamma ray limits. Only rates less than 0.3 century^-1 are acceptable at >5% confidence, and this means that the yield per event must be >10^-3 M(sub)solar mass to produce the requisite 44Ca. Rates this low are incompatible with current estimates for Type II supernovae and yields this high are also very difficult to understand for any standard supernova models. This situation is puzzling. Searches for 60Fe gamma rays have also produced only upper limits, corresponding to a limit of 1.7 M(sub)solar mass in the present interstellar medium. Given the usual assumption of steady state between production and decay, the current rate of synthesis of 60Fe is less than 1.7 M(sub)solar mass/2.2 m.y. It has been suggested that a neutron-rich NSE occurs in small regions in both Type Ia supernovae supernovae and in core-collapse supernovae [7]. Either type might eject significant quantities of 60Fe. If we know the frequency of a particular type of 60Fe-producing event in the past few million years, then we can limit the mean 60Fe mass ejected per event. We have M(sub)ej (60Fe) <= 8 x 10^-5/R(SN) M(sub)solar mass where R(sub)SN is the frequency of the supernovae that eject 60Fe, in number per century. Type Ia supernovae might eject roughly 10^-4 M(sub)solar mass of 60Fe [8], which is very close to this limit. References: [1] Leising M. D. and Share G. H. (1990) Astrophys. J., 357, 638. [2] Kurfess J. D. et al. (1992) Astrophys. J. Lett., 399, L137. [3] Clayton D. D. et al. (1993) Astrophys. J. Lett., submitted. [4] Nomoto K. et al. (1984) Astrophys. J., 286, 644. [5] Woosley S. E. (1988) Proc. Astron. Soc. Aust., 7, 355. [6] Leising M. D. and Share G. H. (1993) Astrophys. J., submitted. [7] Hartmann D. H. et al. (1985) Astrophys. J., 297, 837. [8] Woosley S. E. (1991) In Gamma-Ray Line Astrophysics (P. Durouchoux and N. Prantzos, eds.), 270-290, AIP Conf. Proc. No. 232, New York.

  19. Physics with Radioactive Nuclear Beams

    NASA Astrophysics Data System (ADS)

    Boyd, Richard N.

    The rapidly growing research area of radioactive nuclear beam physics is described. The various types of facilities used at present, and planned for the future, are discussed briefly. Then their uses in research in nuclear physics, astrophysics, and in nuclear-solid state applications are discussed. An intense effort in nuclear reaction physics has been directed toward understanding the neutron halo, a completely new result discovered for very neutron rich nuclei via the use of radioactive nuclear beams. Their use has also produced an immense amount of data on nuclear masses, lifetimes, decay modes, multipole moments, and energy levels. Other areas of research in nuclear physics with radioactive nuclear beams are less well developed, but appear to be promising. In nuclear astro-physics, several of the critical reactions of primordial and stellar nucleosynthesis have been studied. In addition, the use of radioactive nuclear beams has already provided dramatically improved definition of some of the processes of nucleosynthesis which operate near the proton and neutron drip lines, with the promise of much more detailed information to come. In more applied reasearch, the interaction between implanted nuclei and solids has often been used as a tool for nuclear physics, but the same studies can also be used to study properties of solids with previously unachievable sensitivity. The results in the past decade from radioactive nuclear beam research have been both vast and varied, but new facilities and intense interest in the research community should provide new information in the future well beyond that which presently exists.

  20. U-Th disequilibria constraints on physical and chemical erosion processes and rates in soils from the Lake Natron-Lake Magadi (Gregory Rift Valley) drainage area vs hydrology/paleohydrology and bedrock lithology

    NASA Astrophysics Data System (ADS)

    Hillaire-Marcel, Claude

    2015-04-01

    This presentation is a tribute to my former PhD student, the late Dr. Christian Goetz (1960-1991), who carried out intensive field and laboratory investigations on actinides in soils and sediments from lakes Manyara and Natron (Tanzania), and Magadi (Kenya) during his doctoral studies. Soils developed on granites from the Precambrian plateau, west of Gregory Rift, as well as those developed on the trachitic floor of the Rift yield nearly similar patterns, with U-leached (and Th-enriched) upper horizons vs source rocks. They differ from each other by i) the much higher [U]/[Th] mass ratio of soil over the granitic (~ 0.3) vs the trachitic (~ 0.1) basements (both near secular equilibrium), and ii) the greater decay of 230Th-excesses (230Thxs) in top soils over trachites, pointing to much older soils and/or lower leaching rates at the Rift floor. This difference seems related to the more arid conditions prevailing in the deeper part of the Rift. In contrast, soils developed on the basaltic walls of the Rift, characterized by abundant spring water from the basalt aquifer and a dense vegetation, depict a three-stage U-Th isotope evolution, with bedrock at near secular radioactive equilibrium and a [U]/[Th] ratio of ~ 0.2. It is overlain by a U-depleted horizon (with up to 75% relative losses in U), then topped by a low Eh, organic-matter rich layer, with evidence for a secondary uptake of U. The high 230Thxs observed in the U-leached horizon point to relatively fast U-leaching rates and/or "young" soil pattern. The present-day clays deposited in Lake Natron point to a Precambrian granitic plateau origin (through major rivers flowing eastwards towards the lake), whereas clay supplies from the rift escarpment basalts are carried with hydrothermal seepages towards Lake Magadi. U-Th measurements in early diagenetic minerals (phosphates) and clays (smectites) deposited during late Pleistocene high-lake levels (≥ 12 ka BP) provide robust constraints on source-rocks and source minerals, as well as on their paleodrainage patterns and depositional age.

  1. Enhanced Radioactive Material Source Security.

    PubMed

    Klinger, Joseph G

    2016-02-01

    Requirements for additional security measures for sealed radioactive sources have evolved since they were first implemented after the terrorist events of 11 September 2001. This paper will describe the sequence of those measures, commencing with the early orders issued by the U.S. Nuclear Regulatory Commission to the May 2013 adoption of 10 CFR Part 37, Physical Protections of Category 1 and Category 2 Quantities of Radioactive Material. Part 37 requirements will be discussed in detail, as the 37 NRC Agreement States, which regulate approximately 88% of the radioactive material licensees, will be required to enact by 19 March 2016. In addition to the Part 37 requirements, the paper will also highlight some of the other ongoing efforts of the U.S. Department of Energy's National Nuclear Security Administration's Global Threat Reduction Initiative and the Conference of Radiation Control Program Directors. PMID:26717170

  2. Storage containers for radioactive material

    DOEpatents

    Groh, E.F.; Cassidy, D.A.; Dates, L.R.

    1980-07-31

    A radioactive material storage system is claimed for use in the laboratory having a flat base plate with a groove in one surface thereof and a hollow pedestal extending perpendicularly away from the other surface thereof, a sealing gasket in the groove, a cover having a filter therein and an outwardly extending flange which fits over the plate, the groove and the gasket, and a clamp for maintaining the cover and the plate sealed together. The plate and the cover and the clamp cooperate to provide a storage area for radioactive material readily accessible for use or inventory. Wall mounts are provided to prevent accidental formation of critical masses during storage.

  3. Computer Simulation of Radioactive Decay

    NASA Astrophysics Data System (ADS)

    Jesse, Kenneth E.

    2003-12-01

    The straightforward way to determine the half-life of a radioactive substance is to measure its activity in each of a series of time intervals, plot the data as a function of the accumulated time on semilog paper, and then measure the slope of the graph. A computer simulation of this procedure follows based on material presented in Clifford E. Swartz's excellent book, Used Math. He presents a very fine mathematical derivation of the exponential law of decay for radioactive atoms in Chapter 4. A brief summary follows using his notation and equation numbers.

  4. Radioactive dating of the elements

    NASA Technical Reports Server (NTRS)

    Cowan, John J.; Thielemann, Friedrich-Karl; Truran, James W.

    1991-01-01

    The extent to which an accurate determination of the age of the Galaxy, and thus a lower bound on the age of the universe, can be obtained from radioactive dating is discussed. Emphasis is given to the use of the long-lived radioactive nuclei Re-187, Th-232, U-238, and U-235. The nature of the production sites of these and other potential Galactic chronometers is examined along with their production ratios. Age determinations from models of nucleocosmochronology are reviewed and compared with age determination from stellar sources and age constraints form cosmological considerations.

  5. Induced radioactivity in LDEF components

    NASA Technical Reports Server (NTRS)

    Harmon, B. A.; Fishman, G. J.; Parnell, T. A.; Laird, C. E.

    1992-01-01

    A systematic study of the induced radioactivity of the Long Duration Exposure Facility (LDEF) is being carried out in order to gather information about the low earth orbit radiation environment and its effects on materials. The large mass of the LDEF spacecraft, its stabilized configuration, and long mission duration have presented an opportunity to determine space radiation-induced radioactivities with a precision not possible before. Data presented include preliminary activities for steel and aluminum structural samples, and activation subexperiment foils. Effects seen in the data show a clear indication of the trapped proton anisotropy in the South Atlantic Anomaly and suggest contributions from different sources of external radiation fluxes.

  6. Radioactive Ion Beams and Radiopharmaceuticals

    NASA Astrophysics Data System (ADS)

    Laxdal, R. E.; Morton, A. C.; Schaffer, P.

    2014-02-01

    Experiments performed at radioactive ion beam facilities shed new light on nuclear physics and nuclear structure, as well as nuclear astrophysics, materials science and medical science. The many existing facilities, as well as the new generation of facilities being built and those proposed for the future, are a testament to the high interest in this rapidly expanding field. The opportunities inherent in radioactive beam facilities have enabled the search for radioisotopes suitable for medical diagnosis or therapy. In this article, an overview of the production techniques and the current status of RIB facilities and proposals will be presented. In addition, accelerator-generated radiopharmaceuticals will be reviewed.

  7. Storage containers for radioactive material

    DOEpatents

    Groh, Edward F. (Naperville, IL); Cassidy, Dale A. (Valparaiso, IN); Dates, Leon R. (Elmwood Park, IL)

    1981-01-01

    A radioactive material storage system for use in the laboratory having a flat base plate with a groove in one surface thereof and a hollow pedestal extending perpendicularly away from the other surface thereof, a sealing gasket in the groove, a cover having a filter therein and an outwardly extending flange which fits over the plate, the groove and the gasket, and a clamp for maintaining the cover and the plate sealed together, whereby the plate and the cover and the clamp cooperate to provide a storage area for radioactive material readily accessible for use or

  8. National survey on the natural radioactivity and 222Rn exhalation rate of building materials in The Netherlands.

    PubMed

    de Jong, P; van Dijk, W; van der Graaf, E R; de Groot, T J H

    2006-09-01

    The present study reports on results of a nation-wide survey on the natural radioactivity concentrations and Rn exhalation rates of the prevailing building materials in the Netherlands. In total 100 samples were taken and analyzed for the activity concentrations of Ra, Ra, Th, and K and for their Rn exhalation rate. The sampled materials consisted of gypsum products, aerated concrete, sand-lime and clay bricks, mortars and concrete, representing about 95% of the stony building materials used in the construction of Dutch homes. The laboratory analyses were performed according to two well-documented standard procedures, the interlaboratory reproducibility of which is found to be within 5% on average. The highest radionuclide concentrations were found in a porous inner wall brick to which fly ash was added. The second highest were clay bricks with average Ra and Ra levels around 40 Bq kg. Concrete and mortar show the highest exhalation rates with a fairly broad range of 1 to 13 microBq (kg s). Low natural radioactivity levels are associated with either natural gypsum (products) or gypsum from flue gas desulphurization units, and low exhalation rates with clay bricks. To evaluate the radiological impact the radioactivity concentrations in each sample were combined into a so-called dose factor, representing the absorbed dose rate in a room with a floor, walls and ceiling of 20 cm of the material in question. For that purpose, calculations with the computer codes MCNP, Marmer and MicroShield on the specific absorbed dose rates were incorporated in the paper. The results of these codes corresponded within 6% and average values were calculated at 0.90, 1.10, and 0.080 nGy h per Bq kg for the U series, the Th series, and K, respectively. Model calculations on the external dose rate, based on the incidence of the various building materials in 1,336 living rooms, are in accordance with measured data. PMID:16891895

  9. Nuclear structure from radioactive decay

    SciTech Connect

    Wood, J.L.

    1990-09-30

    This report discusses the nuclear structure of the following isotopes as a result of radioactive decays: neutron-deficient iridium isotopes; neutron-deficient platinum isotopes; neutron-deficient gold isotopes; neutron-deficient mercury isotopes; neutron-deficient thallium isotopes; neutron-deficient lead isotopes; neutron-deficient promethium isotopes; and neutron-deficient samarium isotopes.

  10. Radioactivity and the Biology Teacher

    ERIC Educational Resources Information Center

    Hornsey, D. J.

    1974-01-01

    Discusses minimum necessary nuclear fundamentals of radioactive isotopes such as levels of activity, specific activity and the use of carrier materials. Corrections that need to be taken into account in using an isotope to obtain a valid result are also described and statistics for a valid result are included. (BR)

  11. Radioactive tracers and the heart

    SciTech Connect

    Wagner, H.N. Jr.; Buchanan, J.W.

    1980-01-01

    The most widely used tracer for the study of the heart muscle is thallium-201. The principal advantage of radioactive tracers in the study of the heart is that they tell us about regional as well as an overall function. In some cases a regional abnormality may be detected before the overall function of the heart is impaired.

  12. High-Level Radioactive Waste.

    ERIC Educational Resources Information Center

    Hayden, Howard C.

    1995-01-01

    Presents a method to calculate the amount of high-level radioactive waste by taking into consideration the following factors: the fission process that yields the waste, identification of the waste, the energy required to run a 1-GWe plant for one year, and the uranium mass required to produce that energy. Briefly discusses waste disposal and…

  13. High-Level Radioactive Waste.

    ERIC Educational Resources Information Center

    Hayden, Howard C.

    1995-01-01

    Presents a method to calculate the amount of high-level radioactive waste by taking into consideration the following factors: the fission process that yields the waste, identification of the waste, the energy required to run a 1-GWe plant for one year, and the uranium mass required to produce that energy. Briefly discusses waste disposal and

  14. Radioactive particles in dose assessments.

    PubMed

    Dale, P; Robertson, I; Toner, M

    2008-10-01

    Radioactive particles present a novel exposure pathway for members of the public. For typical assessments of potential doses received by members of the public, habit surveys and environmental monitoring combine to allow the assessment to occur. In these circumstances it is believed that the probability of encounter/consumption is certain. The potential detriment is assessed through sampling the use of environmental monitoring data and dose coefficients such as that in ICRP 60 [ICRP, 1990. 1990 Recommendations of the international commission on radiological protection. Publication 60. Annals of the ICRP 21 (1-3)]. However, radioactive particles often represent a hazard that is difficult to quantify and where the probability of encounter is less than certain as are the potential effects on health. Normal assessment methodologies through sampling and analysis are not appropriate for assessing the impact of radioactive particles either prospectively or retrospectively. This paper details many of the issues that should be considered when undertaking an assessment of the risk to health posed by radioactive particles. PMID:18657886

  15. RadioActive101 Practices

    ERIC Educational Resources Information Center

    Brites, Maria José; Ravenscroft, Andrew; Dellow, James; Rainey, Colin; Jorge, Ana; Santos, Sílvio Correia; Rees, Angela; Auwärter, Andreas; Catalão, Daniel; Balica, Magda; Camilleri, Anthony F.

    2014-01-01

    In keeping with the overarching RadioActive101 (RA101) spirit and ethos, this report is the product of collaborative and joined-up thinking from within the European consortium spread across five countries. As such, it is not simply a single voice reporting on the experiences and knowledge gained during the project. Rather it is a range of…

  16. Method for treating radioactive liquids

    SciTech Connect

    Komrow, R.R.; Pritchard, J.F.

    1980-11-25

    A process for treating and handling radioactive liquids and rendering such liquids safe for handling is disclosed. Transportation and disposal, the process comprises adding thereto a small amount of a water-insoluble alkali salt of an aqueous alkali saponified gelatinized-starch-polyacrylonitrile graft polymer, to form a solid, semi-solid or gel product.

  17. Sensor integration in radioactive environments

    NASA Astrophysics Data System (ADS)

    Harfensteller, Mark; Schilp, Michael; Eursch, Andreas; Zaeh, Michael F.

    2004-12-01

    Radioactive material of high activity levels has to be handled in a nuclear medicine environment. Until now most of these activities are done manually or by rudimentally automated processes. To increase radiation safety and process quality, smart automation strategies for these processes have to be developed. Especially long-term processes with radioactive materials have to be automated in early stages of development. This leads to a certain flexibility regarding requirements demanding an adjustable automation concept. The application of radiation hardened sensors is expensive but even these sensors will be destroyed by radiation effects. To allow therefore standard sensors to be used in radioactive environments, different strategies have been tested: In general, the sensors must be applied in a way to allow an easy access to sensors for replacement purposes. But this approach might not be sophisticated. An additional solution is the reduction of exposure of sensitive parts such as electronics. This means dividing the sensor in a measuring part which is placed in the radioactive environment and in a sensitive, shielded control part as it is realized by fibre optic sensors. The implementation of these approaches is demonstrated in sensor applications for radium handling systems e. g. contactless control of the needle clearance of a dispensing system via a fibre optic sensor. Further scenarios for sensor integration problems are presented in this paper.

  18. Coal Ash Contains High Levels of Radioactivity

    MedlinePLUS

    ... 154590.html Coal Ash Contains High Levels of Radioactivity: Study End product from coal-fired plants may ... 2015 (HealthDay News) -- Coal ash contains levels of radioactivity that raise concern about the environment and human ...

  19. Radioactive Iodine (I-131) Therapy for Hyperthyroidism

    MedlinePLUS

    ... small dose of radioactive iodine I-131 (an isotope of iodine that emits radiation) is swallowed, it ... accelerating the metabolism. Radioactive iodine (I-131), an isotope of iodine that emits radiation, is used for ...

  20. Radioactive Waste Incineration: Status Report

    SciTech Connect

    Diederich, A.R.; Akins, M.J.

    2008-07-01

    Incineration is generally accepted as a method of reducing the volume of radioactive waste. In some cases, the resulting ash may have high concentrations of materials such as Plutonium or Uranium that are valuable materials for recycling. Incineration can also be effective in treating waste that contains hazardous chemicals as well as radioactive contamination. Despite these advantages, the number of operating incinerators currently in the US currently appears to be small and potentially declining. This paper describes technical, regulatory, economic and political factors that affect the selection of incineration as a preferred method of treating radioactive waste. The history of incinerator use at commercial and DOE facilities is summarized, along with the factors that have affected each of the sectors, thus leading to the current set of active incinerator facilities. In summary: Incineration has had a long history of use in radioactive waste processing due to their ability to reduce the volume of the waste while destroying hazardous chemicals and biological material. However, combinations of technical, regulatory, economic and political factors have constrained the overall use of incineration. In both the Government and Private sectors, the trend is to have a limited number of larger incineration facilities that treat wastes from a multiple sites. Each of these sector is now served by only one or two incinerators. Increased use of incineration is not likely unless there is a change in the factors involved, such as a significant increase in the cost of disposal. Medical wastes with low levels of radioactive contamination are being treated effectively at small, local incineration facilities. No trend is expected in this group. (authors)

  1. 49 CFR 175.705 - Radioactive contamination.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Radioactive contamination. 175.705 Section 175.705... Regulations Applicable According to Classification of Material 175.705 Radioactive contamination. (a) A... (radioactive) materials that may have been released from their packagings. (b) When contamination is present...

  2. 49 CFR 175.705 - Radioactive contamination.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Radioactive contamination. 175.705 Section 175.705... Regulations Applicable According to Classification of Material 175.705 Radioactive contamination. (a) A... (radioactive) materials that may have been released from their packagings. (b) When contamination is present...

  3. 49 CFR 175.705 - Radioactive contamination.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Radioactive contamination. 175.705 Section 175.705... Regulations Applicable According to Classification of Material 175.705 Radioactive contamination. (a) A... (radioactive) materials that may have been released from their packagings. (b) When contamination is present...

  4. 49 CFR 175.705 - Radioactive contamination.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Radioactive contamination. 175.705 Section 175.705... Regulations Applicable According to Classification of Material 175.705 Radioactive contamination. (a) A... (radioactive) materials that may have been released from their packagings. (b) When contamination is present...

  5. 49 CFR 175.705 - Radioactive contamination.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Radioactive contamination. 175.705 Section 175.705... Regulations Applicable According to Classification of Material 175.705 Radioactive contamination. (a) A... (radioactive) materials that may have been released from their packagings. (b) When contamination is present...

  6. 10 CFR 39.47 - Radioactive markers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Radioactive markers. 39.47 Section 39.47 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment 39.47 Radioactive markers. The licensee may use radioactive markers in wells only if the individual markers...

  7. 10 CFR 39.47 - Radioactive markers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Radioactive markers. 39.47 Section 39.47 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment 39.47 Radioactive markers. The licensee may use radioactive markers in wells only if the individual markers...

  8. 10 CFR 39.47 - Radioactive markers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Radioactive markers. 39.47 Section 39.47 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment 39.47 Radioactive markers. The licensee may use radioactive markers in wells only if the individual markers...

  9. 10 CFR 39.47 - Radioactive markers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Radioactive markers. 39.47 Section 39.47 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment 39.47 Radioactive markers. The licensee may use radioactive markers in wells only if the individual markers...

  10. 10 CFR 39.47 - Radioactive markers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Radioactive markers. 39.47 Section 39.47 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment 39.47 Radioactive markers. The licensee may use radioactive markers in wells only if the individual markers...

  11. 46 CFR 147.100 - Radioactive materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... (NRC) under 10 CFR parts 30 and 34. (b) Stowage of radioactive materials must conform to the... 46 Shipping 5 2013-10-01 2013-10-01 false Radioactive materials. 147.100 Section 147.100 Shipping... Stowage and Other Special Requirements for Particular Materials § 147.100 Radioactive materials....

  12. 46 CFR 147.100 - Radioactive materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... (NRC) under 10 CFR parts 30 and 34. (b) Stowage of radioactive materials must conform to the... 46 Shipping 5 2012-10-01 2012-10-01 false Radioactive materials. 147.100 Section 147.100 Shipping... Stowage and Other Special Requirements for Particular Materials § 147.100 Radioactive materials....

  13. 46 CFR 147.100 - Radioactive materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... (NRC) under 10 CFR parts 30 and 34. (b) Stowage of radioactive materials must conform to the... 46 Shipping 5 2010-10-01 2010-10-01 false Radioactive materials. 147.100 Section 147.100 Shipping... Stowage and Other Special Requirements for Particular Materials § 147.100 Radioactive materials....

  14. 46 CFR 147.100 - Radioactive materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... (NRC) under 10 CFR parts 30 and 34. (b) Stowage of radioactive materials must conform to the... 46 Shipping 5 2011-10-01 2011-10-01 false Radioactive materials. 147.100 Section 147.100 Shipping... Stowage and Other Special Requirements for Particular Materials 147.100 Radioactive materials....

  15. Radioactive waste treatment technologies and environment

    SciTech Connect

    HORVATH, Jan; KRASNY, Dusan

    2007-07-01

    The radioactive waste treatment and conditioning are the most important steps in radioactive waste management. At the Slovak Electric, plc, a range of technologies are used for the processing of radioactive waste into a form suitable for disposal in near surface repository. These technologies operated by JAVYS, PLc. Nuclear and Decommissioning Company, PLc. Jaslovske Bohunice are described. Main accent is given to the Bohunice Radwaste Treatment and Conditioning Centre, Bituminization plant, Vitrification plant, and Near surface repository of radioactive waste in Mochovce and their operation. Conclusions to safe and effective management of radioactive waste in the Slovak Republic are presented. (authors)

  16. Public attitudes about radioactive waste

    SciTech Connect

    Bisconti, A.S.

    1992-12-31

    Public attitudes about radioactive waste are changeable. That is my conclusion from eight years of social science research which I have directed on this topic. The fact that public attitudes about radioactive waste are changeable is well-known to the hands-on practitioners who have opportunities to talk with the public and respond to their concerns-practitioners like Ginger King, who is sharing the podium with me today. The public`s changeability and open-mindedness are frequently overlooked in studies that focus narrowly on fear and dread. Such studies give the impression that the outlook for waste disposal solutions is dismal. I believe that impression is misleading, and I`d like to share research findings with you today that give a broader perspective.

  17. Radioactive waste shredding: Preliminary evaluation

    SciTech Connect

    Soelberg, N.R.; Reimann, G.A.

    1994-07-01

    The critical constraints for sizing solid radioactive and mixed wastes for subsequent thermal treatment were identified via a literature review and a survey of shredding equipment vendors. The types and amounts of DOE radioactive wastes that will require treatment to reduce the waste volume, destroy hazardous organics, or immobilize radionuclides and/or hazardous metals were considered. The preliminary steps of waste receipt, inspection, and separation were included because many potential waste treatment technologies have limits on feedstream chemical content, physical composition, and particle size. Most treatment processes and shredding operations require at least some degree of feed material characterization. Preliminary cost estimates show that pretreatment costs per unit of waste can be high and can vary significantly, depending on the processing rate and desired output particle size.

  18. Nuclear structure from radioactive decay

    SciTech Connect

    Wood, J.L.

    1989-09-30

    A program has been initiated to systematically study the structure of the very neutron-deficient nuclei in and near the region of deformation with Z > 50, N < 82. This has necessitated ion-source development. Radioactive decay is the only way to observe low-spin states in this region. Only with such information will details of the nuclear shape and nuclear stability in this new region of deformation be understood. This report discusses work done in this Z region.

  19. Nuclear structure from radioactive decay

    SciTech Connect

    Wood, J.L.

    1991-09-30

    This report discusses nuclear structure from radioactive decay of the following: Neutron-Deficient Iridium Isotopes; Neutron-Deficient Platinum Isotopes; Neutron-Deficient Gold Isotopes; Neutron-Deficient Mercury Isotopes; Neutron-Deficient Thallium Isotopes; Neutron-Deficient Lead Isotopes; Neutron-Deficient Samarium Isotopes; Neutron-Deficient Promethium Isotopes; Neutron-Deficient Neodymium Isotopes; and Neutron-Deficient Praseodymium Isotopes. Also discussed are Nuclear Systematics and Models.

  20. Radioactive substances in tap water.

    PubMed

    Atsuumi, Ryo; Endo, Yoshihiko; Suzuki, Akihiko; Kannotou, Yasumitu; Nakada, Masahiro; Yabuuchi, Reiko

    2014-01-01

    A 9.0 magnitude (M) earthquake with an epicenter off the Sanriku coast occurred at 14: 46 on March 11, 2011. TEPCO Fukushima Daiichi Nuclear Power Plant (F-1 NPP) was struck by the earthquake and its resulting tsunami. Consequently a critical nuclear disaster developed, as a large quantity of radioactive materials was released due to a hydrogen blast. On March 16(th), 2011, radioiodine and radioactive cesium were detected at levels of 177 Bq/kg and 58 Bq/kg, respectively, in tap water in Fukushima city (about 62km northwest of TEPCO F-1 NPP). On March 20th, radioiodine was detected in tap water at a level of 965 Bq/kg, which is over the value-index of restrictions on food and drink intake (radioiodine 300 Bq/kg (infant intake 100 Bq/kg)) designated by the Nuclear Safety Commission. Therefore, intake restriction measures were taken regarding drinking water. After that, although the all intake restrictions were lifted, in order to confirm the safety of tap water, an inspection system was established to monitor all tap water in the prefecture. This system has confirmed that there has been no detection of radioiodine or radioactive cesium in tap water in the prefecture since May 5(th), 2011. Furthermore, radioactive strontium ((89) Sr, (90)Sr) and plutonium ((238)Pu, (239)Pu+(240)Pu) in tap water and the raw water supply were measured. As a result, (89) Sr, (238)Pu, (239)Pu+(240)Pu were undetectable and although (90)Sr was detected, its committed effective dose of 0.00017 mSv was much lower than the yearly 0.1 mSv of the World Health Organization guidelines for drinking water quality. In addition, the results did not show any deviations from past inspection results. PMID:25030724

  1. Optimization of radioactive waste storage.

    PubMed

    Dellamano, Jos Claudio; Sordi, Gian-Maria A A

    2007-02-01

    In several countries, low-level radioactive wastes are treated and stored awaiting construction and operation of a final repository. In some cases, interim storage may be extended for decades requiring special attention regarding security issues. The International Atomic Energy Agency (IAEA) recommends segregation of wastes that may be exempted from interim storage or ultimate disposal. The paper presents a method to optimize the decision making process regarding exemption vs. interim storage or ultimate disposal of these wastes. PMID:17228185

  2. Environmental Geochemistry of Radioactive Contamination

    NASA Astrophysics Data System (ADS)

    Siegel, M. D.; Bryan, C. R.

    2003-12-01

    Psychometric studies of public perception of risk have shown that dangers associated with radioactive contamination are considered the most dreaded and among the least understood hazards (Slovic, 1987). Fear of the risks associated with nuclear power and associated contamination has had important effects on policy and commercial decisions in the last few decades. In the US, no new nuclear power plants were ordered between 1978 and 2002, even though it has been suggested that the use of nuclear power has led to significantly reduced CO2 emissions and may provide some relief from the potential climatic changes associated with fossil fuel use. The costs of the remediation of sites contaminated by radioactive materials and the projected costs of waste disposal of radioactive waste in the US dwarf many other environmental programs. The cost of disposal of spent nuclear fuel at the proposed repository at Yucca Mountain will likely exceed 10 billion. The estimated total life cycle cost for remediation of US Department of Energy (DOE) weapons production sites ranged from 203-247 billion dollars in constant 1999 dollars, making the cleanup the largest environmental project on the planet (US DOE, 2001). Estimates for the cleanup of the Hanford site alone exceeded $85 billion through 2046 in some of the remediation plans.Policy decisions concerning radioactive contamination should be based on an understanding of the potential migration of radionuclides through the geosphere. In many cases, this potential may have been overestimated, leading to decisions to clean up contaminated sites unnecessarily and exposing workers to unnecessary risk. It is important for both the general public and the scientific community to be familiar with information that is well established, to identify the areas of uncertainty and to understand the significance of that uncertainty to the assessment of risk.

  3. Radioactive Waste Management BasisApril 2006

    SciTech Connect

    Perkins, B K

    2011-08-31

    This Radioactive Waste Management Basis (RWMB) documents radioactive waste management practices adopted at Lawrence Livermore National Laboratory (LLNL) pursuant to Department of Energy (DOE) Order 435.1, Radioactive Waste Management. The purpose of this Radioactive Waste Management Basis is to describe the systematic approach for planning, executing, and evaluating the management of radioactive waste at LLNL. The implementation of this document will ensure that waste management activities at LLNL are conducted in compliance with the requirements of DOE Order 435.1, Radioactive Waste Management, and the Implementation Guide for DOE Manual 435.1-1, Radioactive Waste Management Manual. Technical justification is provided where methods for meeting the requirements of DOE Order 435.1 deviate from the DOE Manual 435.1-1 and Implementation Guide.

  4. Disposition of intravenous radioactive acyclovir

    SciTech Connect

    de Miranda, P.; Good, S.S.; Laskin, O.L.; Krasny, H.C.; Connor, J.D.; Lietman, P.S.

    1981-11-01

    The kinetic and metabolic disposition of (8-14C)acyclovir (ACV) was investigated in five subjects with advanced malignancy. The drug was administered by 1-hr intravenous infusion at doses of 0.5 and 2.5 mg/kg. Plasma and blood radioactivity-time, and plasma concentration-time data were defined by a two-compartment open kinetic model. There was nearly equivalent distribution of radioactivity in blood and plasma. The overall mean plasma half-life and total body clearance +/- SD of ACV were 2.1 +/- 0.5 hr and 297 +/- 53 ml/min/1.73 m2. Binding of ACV to plasma proteins was 15.4 +/- 4.4%. Most of the radioactive dose excreted was recovered in the urine (71% to 99%) with less than 2% excretion in the feces and only trace amounts in the expired Co2. Analyses by reverse-phase high-performance liquid chromatography indicated that 9-(carboxymethoxymethyl)guanine was the only significant urinary metabolite of ACV, accounting for 8.5% to 14.1% of the dose. A minor metabolite (less than 0.2% of dose) had the retention time of 8-hydroxy-9-((2-hydroxyethoxy)methyl)guanine. Unchanged urinary ACV ranged from 62% to 91% of the dose. There was no indication of ACV cleavage to guanine. Renal clearance of ACV was approximately three times the corresponding creatinine clearances.

  5. Radioactivity of spent TRIGA fuel

    NASA Astrophysics Data System (ADS)

    Usang, M. D.; Nabil, A. R. A.; Alfred, S. L.; Hamzah, N. S.; Abi, M. J. B.; Rawi, M. Z. M.; Abu, M. P.

    2015-04-01

    Some of the oldest TRIGA fuel in the Malaysian Reaktor TRIGA PUSPATI (RTP) is approaching the limit of its end of life with burn-up of around 20%. Hence it is prudent for us to start planning on the replacement of the fuel in the reactor and other derivative activities associated with it. In this regard, we need to understand all of the risk associated with such operation and one of them is to predict the radioactivity of the fuel, so as to estimate the safety of our working conditions. The radioactivity of several fuels are measured and compared with simulation results to confirm the burnup levels of the selected fuels. The radioactivity measurement are conducted inside the water tank to reduce the risk of exposure and in this case the detector wrapped in plastics are lowered under water. In nuclear power plant, the general practice was to continuously burn the fuel. In research reactor, most operations are based on the immediate needs of the reactor and our RTP for example operate periodically. By integrating the burnup contribution for each core configuration, we simplify the simulation of burn up for each core configuration. Our results for two (2) fuel however indicates that the dose from simulation underestimate the actual dose from our measurements. Several postulates are investigated but the underlying reason remain inconclusive.

  6. Radioactivity of spent TRIGA fuel

    SciTech Connect

    Usang, M. D. Nabil, A. R. A.; Alfred, S. L.; Hamzah, N. S.; Abi, M. J. B.; Rawi, M. Z. M.; Abu, M. P.

    2015-04-29

    Some of the oldest TRIGA fuel in the Malaysian Reaktor TRIGA PUSPATI (RTP) is approaching the limit of its end of life with burn-up of around 20%. Hence it is prudent for us to start planning on the replacement of the fuel in the reactor and other derivative activities associated with it. In this regard, we need to understand all of the risk associated with such operation and one of them is to predict the radioactivity of the fuel, so as to estimate the safety of our working conditions. The radioactivity of several fuels are measured and compared with simulation results to confirm the burnup levels of the selected fuels. The radioactivity measurement are conducted inside the water tank to reduce the risk of exposure and in this case the detector wrapped in plastics are lowered under water. In nuclear power plant, the general practice was to continuously burn the fuel. In research reactor, most operations are based on the immediate needs of the reactor and our RTP for example operate periodically. By integrating the burnup contribution for each core configuration, we simplify the simulation of burn up for each core configuration. Our results for two (2) fuel however indicates that the dose from simulation underestimate the actual dose from our measurements. Several postulates are investigated but the underlying reason remain inconclusive.

  7. Evaluation of heat generation by radioactive decay of sedimentary rocks in Eastern Desert and Nile Valley, Egypt.

    PubMed

    Abbady, Adel G E

    2010-10-01

    Radioactive heat-production (RHP) data of sedimentary outcrops in Gebel Anz (Eastern Desert) and Gebel Sarai (Nile Valley) are presented. A total of 103 rock samples were investigated, covering all major rock types of the areas. RHP were derived from uranium, thorium and potassium concentrations measured from gamma-radiation originating from the decay of (214)Bi ((238)U series), (208)Tl ((232)Th series) and the primary decay of (40)K, obtained with a NaI (Tl) detector. The heat-production rate of Gebel Anz ranges from 0.94 (Nubai Sandstone ) to 5.22 microW m(-3) (Duwi Formation). In Gebel Sarai it varies from 0.82 (Esna Shale) to 7 microW m(-3) (Duwi Formation). The contribution due to U is about 62%, from Th is 34% and 4% from K in Gebel Anz. The corresponding values in Gebel Sarai are 69.6%, 26.9% and 3.5%, respectively. These data can be used to discuss the effects of the lateral variation of the RHP rate on the heat flux and the temperature fields in the upper crust. PMID:20472452

  8. Radioactive characterization of the main materials involved in the titanium dioxide production process and their environmental radiological impact.

    PubMed

    Mantero, J; Gazquez, M J; Bolivar, J P; Garcia-Tenorio, R; Vaca, F

    2013-06-01

    A study about the distribution of several radionuclides from the uranium and the thorium series radionuclides along the production process of a typical NORM industry devoted to the production of titanium dioxide has been performed. With this end the activity concentrations in raw materials, final product, co-products, and wastes of the production process have been determined by both gamma-ray and alpha-particle spectrometry. The main raw material used in the studied process (ilmenite) presents activity concentrations of around 300Bqkg(-1) for Th-series radionuclides and 100Bqkg(-1) for the U-series ones. These radionuclides in the industrial process are distributed in the different steps of the production process according mostly to the chemical behaviour of each radioelement, following different routes. As an example, most of the radium remains associated with the un-dissolved material waste, with activity concentrations around 3kBqkg(-1) of (228)Ra and around 1kBqkg(-1) of (226)Ra, while the final commercial products (TiO2 pigments and co-products) contain negligible amounts of radioactivity. The obtained results have allowed assessing the possible public radiological impact associated with the use of the products and co-products obtained in this type of industry, as well as the environmental radiological impact associated with the solid residues and liquid generated discharges. PMID:23416226

  9. SHIPPING CONTAINER FOR RADIOACTIVE MATERIAL

    DOEpatents

    Nachbar, H.D.; Biggs, B.B.; Tariello, P.J.; George, K.O.

    1963-01-15

    A shipping container is described for transponting a large number of radioactive nuclear fuel element modules which produce a substantial amount of heat. The container comprises a primary pressure vessel and shield, and a rotatable head having an access port that can be indexed with module holders in the container. In order to remove heat generated in the fuel eleme nts, a heat exchanger is arranged within the container and in contact with a heat exchange fluid therein. The heat exchanger communicates with additional external heat exchangers, which dissipate heat to the atmosphere. (AEC)

  10. Radioactive Waste Management BasisSept 2001

    SciTech Connect

    Goodwin, S S

    2011-08-31

    This Radioactive Waste Management Basis (RWMB) documents radioactive waste management practices adopted at Lawrence Livermore National Laboratory (LLNL) pursuant to Department of Energy (DOE) Order 435.1, Radioactive Waste Management. The purpose of this RWMB is to describe the systematic approach for planning, executing, and evaluating the management of radioactive waste at LLNL. The implementation of this document will ensure that waste management activities at LLNL are conducted in compliance with the requirements of DOE Order 435.1, Radioactive Waste Management, and the Implementation Guide for DOE manual 435.1-1, Radioactive Waste Management Manual. Technical justification is provided where methods for meeeting the requirements of DOE Order 435.1 deviate from the DOE Manual 435.1-1 and Implementation Guide.

  11. Assessing postzygotic isolation using zygotic disequilibria in natural hybrid zones.

    PubMed

    Hu, Xin-Sheng; Yeh, Francis C

    2014-01-01

    Hybrid zones as windows on evolutionary processes provide a natural laboratory for studying the genetic basis and mechanisms of postzygotic isolation. One resultant pattern in hybrid zones is the Hardy-Weinberg disequilibrium (HWD) for a single locus or the linkage disequilibrium (LD) for multiple loci produced by natural selection against hybrids. However, HWD and the commonly used low-order gametic or composite digenic LD cannot fully reflect the pattern of the high-order genotypic interactions. Here we propose the use of zygotic LD to elucidate the selection mechanisms of postzygotic isolation, and its calculation is based on genotypic frequencies only, irrespective of the type of mating system. We numerically and analytically show that the maximum composite digenic LD is always greater than the maximum absolute zygotic LD under the linear-additive selection, but is comparable to or smaller than the maximum absolute zygotic LD under the strong epistatic selection. Selection mechanisms can be inferred by testing such differences. We analyze a previously reported mouse hybrid zone assayed with genome-wide SNPs, and confirm that the composite digenic LD cannot appropriately indicate all possible significant genotypic interactions for a given SNP pair. A large proportion of significant zygotic LDs, ?75% in general in the mouse hybrid zone, cannot be revealed from the composite digenic LD analysis. Statistical tests indicate that epistatic selection occurred among multiple loci in the mouse hybrid zone. The results highlight that the joint patterns of the composite digenic and zygotic LDs can help to elucidate the selection mechanism that is potentially involved in postzygotic isolation. PMID:24950065

  12. Exoplanets' atmospheres: comparing and separating different sources of disequilibria

    NASA Astrophysics Data System (ADS)

    Simoncini, Eugenio; Brucato, John Robert

    The atmosphere of the only known (till nowadays) inhabited planet is characterized by a unique disequilibrium state in terms of chemical composition. Studying this state of disequilibrium is important for its potential role in the detection of life on other suitable planets [1][2][3]. However, different processes are able to produce chemical disequilibrium in planetary atmospheres, thus a tool to compute the extent of disequilibrium is needed. We developed a methodology to calculate the extent of atmospheric chemical disequilibrium [3][4]. A new computational framework called KROME has been applied to atmospheric models in order to give a correct computation of reaction? kinetics [5]. This methodology allows to compute, for models of different planets, the extent of disequilibrium due to several processes, such as fast vertical mixing, eddy diffusion, photochemistry, extremely diverse atmospheres due to tidal effect. Using Earths models, we also infer the potential extension of the effect of a biosphere on disequilibrium. Our results provide a comprehensive analysis of atmospheric disequilibrium for rocky planets, which can be also used for the detection of habitable conditions on farther planetary bodies. [1] Lovelock, J. E.: A physical basis for life detection experiments, Nature, 207, 568 (1965) [2] Kleidon, A., Physics of Life Reviews, 7, 424 (2010) [3] Simoncini E., Grassi T., Disequilibrium in planetary atmospheres: a first calculation for Earth using KROME, submitted to OLEB. [4] Kondepudi D., Prigogine I., Modern Thermodynamics, Wiley (1996) [5] Grassi, T., Bovino, S., Schleicher, D. R. G., Prieto, J., Seifried, D., Simoncini, E., Gianturco, F. A., in press on Mon. Not. R. Astron. Soc. MN-13-2848-MJ.R1

  13. Method for making a partitioning radioactive tracer

    SciTech Connect

    Gant, P.L.

    1989-08-15

    This patent describes a method of preparing a radioactive iodoethanol tracer material. It comprises: combining chloroethanol and an alkali-metal salt of radioactive iodine; reacting the combined materials in the presence of activated carbon for a time sufficient to exchange substantially all the iodine in the salt with chlorine in the chloroethanol; and recovering a reaction product containing radioactive iodoethanol produced by the reaction.

  14. [Microbiological Aspects of Radioactive Waste Storage].

    PubMed

    Safonov, A V; Gorbunova, O A; German, K E; Zakharova, E V; Tregubova, V E; Ershov, B G; Nazina, T N

    2015-01-01

    The article gives information about the microorganisms inhabiting in surface storages of solid radioactive waste and deep disposal sites of liquid radioactive waste. It was shown that intensification of microbial processes can lead to significant changes in the chemical composition and physical state of the radioactive waste. It was concluded that the biogeochemical processes can have both a positive effect on the safety of radioactive waste storages (immobilization of RW macrocomponents, a decreased migration ability of radionuclides) and a negative one (biogenic gas production in subterranean formations and destruction of cement matrix). PMID:26310021

  15. The Model 9977 Radioactive Material Packaging Primer

    SciTech Connect

    Abramczyk, G.

    2015-10-09

    The Model 9977 Packaging is a single containment drum style radioactive material (RAM) shipping container designed, tested and analyzed to meet the performance requirements of Title 10 the Code of Federal Regulations Part 71. A radioactive material shipping package, in combination with its contents, must perform three functions (please note that the performance criteria specified in the Code of Federal Regulations have alternate limits for normal operations and after accident conditions): Containment, the package must “contain” the radioactive material within it; Shielding, the packaging must limit its users and the public to radiation doses within specified limits; and Subcriticality, the package must maintain its radioactive material as subcritical

  16. Cosmic radioactivity and INTEGRAL results

    NASA Astrophysics Data System (ADS)

    Diehl, Roland

    2014-05-01

    Gamma-ray lines from radioactive decay of unstable isotopes co-produced by nucleosynthesis in massive stars and supernova have been measured since more than thirty years. Over the past ten years, INTEGRAL complemented the first sky survey made by COMPTEL. The 26A1 isotope with 1 My decay time had been first direct proof of currently-ongoing nucleosynthesis in our Galaxy. This has now become a tool to study the My history of specific source regions, such as massive-star groups and associations in nearby regions which can be discriminated from the galactic-plane background, and the inner Galaxy, where Doppler shifted lines add to the astronomical information about bar and spiral structure. Recent findings suggest that superbubbles show a remarkable asymmetry, on average, in the spiral arms of our galaxy. 60Fe is co-produced by the sources of 26A1, and the isotopic ratio from their nucleosynthesis encodes stellar-structure information. Annihilation gamma-rays from positrons in interstellar space show a puzzling bright and extended source region central to our Galaxy, but also may be partly related to nucleosynthesis. 56Ni and 44Ti isotope gamma-rays have been used to constrain supernova explosion mechanisms. Here we report latest results using the accumulated multi-year database of INTEGRAL observations, and discuss their astrophysical interpretations, connecting to other traces of cosmic radioactivity and to other cosmic messengers.

  17. Subseabed storage of radioactive waste

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    The subject of the storage of nuclear wastes products incites emotional responses from the public, and thus the U.S. Subseabed Disposal Program will have to make a good case for waste storage beneath the ocean floor. The facts attendant, however, describe circumstances necessitating cool-headed analysis to achieve a solution to the growing nuclear waste problem. Emotion aside, a good case indeed is being made for safe disposal beneath the ocean floor.The problems of nuclear waste storage are acute. A year ago, U.S. military weapons production had accumulated over seventy-five million gallons of high-level radioactive liquid waste; solid wastes, such as spent nuclear fuel rods from reactors, amounted to more than 12,000 tons. These wastes are corrosive and will release heat for 1000 years or more. The wastes will remain dangerously radioactive for a period of 10,000 years. There are advantages in storing the wastes on land, in special underground repositories, or on the surface. These include the accessibility to monitor the waste and the possibility of taking action should a container rupture occur, and thus the major efforts to determine suitable disposal at this time are focused on land-based storage. New efforts, not to be confused with ocean dumping practices of the past, are demonstrating that waste containers isolated in the clays and sediments of the ocean floor may be superior (Environ. Sci. Tech., 16, 28A-37A 1982).

  18. Radioactive material package seal tests

    SciTech Connect

    Madsen, M.M.; Humphreys, D.L.; Edwards, K.R.

    1990-01-01

    General design or test performance requirements for radioactive materials (RAM) packages are specified in Title 10 of the US Code of Federal Regulations Part 71 (US Nuclear Regulatory Commission, 1983). The requirements for Type B packages provide a broad range of environments under which the system must contain the RAM without posing a threat to health or property. Seals that provide the containment system interface between the packaging body and the closure must function in both high- and low-temperature environments under dynamic and static conditions. A seal technology program, jointly funded by the US Department of Energy Office of Environmental Restoration and Waste Management (EM) and the Office of Civilian Radioactive Waste Management (OCRWM), was initiated at Sandia National Laboratories. Experiments were performed in this program to characterize the behavior of several static seal materials at low temperatures. Helium leak tests on face seals were used to compare the materials. Materials tested include butyl, neoprene, ethylene propylene, fluorosilicone, silicone, Eypel, Kalrez, Teflon, fluorocarbon, and Teflon/silicone composites. Because most elastomer O-ring applications are for hydraulic systems, manufacturer low-temperature ratings are based on methods that simulate this use. The seal materials tested in this program with a fixture similar to a RAM cask closure, with the exception of silicone S613-60, are not leak tight (1.0 {times} 10{sup {minus}7} std cm{sup 3}/s) at manufacturer low-temperature ratings. 8 refs., 3 figs., 1 tab.

  19. Radioactivity in the galactic plane

    NASA Technical Reports Server (NTRS)

    Walraven, G. D.; Haymes, R. C.

    1976-01-01

    The paper reports the detection of a large concentration of interstellar radioactivity during balloon-altitude measurements of gamma-ray energy spectra in the band between 0.02 and 12.27 MeV from galactic and extragalactic sources. Enhanced counting rates were observed in three directions towards the plane of the Galaxy; a power-law energy spectrum is computed for one of these directions (designated B 10). A large statistical deviation from the power law in a 1.0-FWHM interval centered near 1.16 MeV is discussed, and the existence of a nuclear gamma-ray line at 1.15 MeV in B 10 is postulated. It is suggested that Ca-44, which emits gamma radiation at 1.156 MeV following the decay of radioactive Sc-44, is a likely candidate for this line, noting that Sc-44 arises from Ti-44 according to explosive models of supernova nucleosynthesis. The 1.16-MeV line flux inferred from the present data is shown to equal the predicted flux for a supernova at a distance of approximately 3 kpc and an age not exceeding about 100 years.

  20. Induced radioactivity in LDEF components

    NASA Technical Reports Server (NTRS)

    Harmon, B. A.; Fishman, G. J.; Parnell, T. A.; Laird, C. E.

    1991-01-01

    The systematics of induced radioactivity on the Long Duration Exposure Facility (LDEF) were studied in a wide range of materials using low level background facilities for detection of gamma rays. Approx. 400 samples of materials processed from structural parts of the spacecraft, as well as materials from onboard experiments, were analyzed at national facilities. These measurements show the variety of radioisotopes that are produced with half-lives greater than 2 wks, most of which are characteristic of proton induced reactions above 20 MeV. For the higher activity, long lived isotopes, it was possible to map the depth and directional dependences of the activity. Due to the stabilized configuration of the LDEF, the induced radioactivity data clearly show contributions from the anisotropic trapped proton flux in the South Atlantic Anomaly. This effect is discussed, along with evidence for activation by galactic protons and thermal neutrons. The discovery of Be-7 was made on leading side parts of the spacecraft, although this was though not to be related to the in situ production of radioisotopes from external particle fluxes.

  1. Cosmic radioactivity and INTEGRAL results

    SciTech Connect

    Diehl, Roland

    2014-05-02

    Gamma-ray lines from radioactive decay of unstable isotopes co-produced by nucleosynthesis in massive stars and supernova have been measured since more than thirty years. Over the past ten years, INTEGRAL complemented the first sky survey made by COMPTEL. The {sup 26}A1 isotope with 1 My decay time had been first direct proof of currently-ongoing nucleosynthesis in our Galaxy. This has now become a tool to study the ∼My history of specific source regions, such as massive-star groups and associations in nearby regions which can be discriminated from the galactic-plane background, and the inner Galaxy, where Doppler shifted lines add to the astronomical information about bar and spiral structure. Recent findings suggest that superbubbles show a remarkable asymmetry, on average, in the spiral arms of our galaxy. {sup 60}Fe is co-produced by the sources of {sup 26}A1, and the isotopic ratio from their nucleosynthesis encodes stellar-structure information. Annihilation gamma-rays from positrons in interstellar space show a puzzling bright and extended source region central to our Galaxy, but also may be partly related to nucleosynthesis. {sup 56}Ni and {sup 44}Ti isotope gamma-rays have been used to constrain supernova explosion mechanisms. Here we report latest results using the accumulated multi-year database of INTEGRAL observations, and discuss their astrophysical interpretations, connecting to other traces of cosmic radioactivity and to other cosmic messengers.

  2. WWW Table of Radioactive Isotopes

    NASA Astrophysics Data System (ADS)

    Firestone, R. B.; Ekstrom, L. P.; Chu, S. Y. F.

    1999-10-01

    An electronic sequel to the Table of Radioactive Isotopes (John Wiley, 1986) is being developed for use on the WWW. Updated adopted and decay data from the Evaluated Nuclear Structure Decay File (ENSDF) and other sources have been combined and edited. Decay scheme normalizations are revised when necessary. Gamma-ray and alpha-particle energies can be searched interactively by energy or parent half-life, mass, and atomic or neutron number. Summary data including half-lives, Q-values, production mode(s), genetic feedings, and a list of references published since the last full evaluation are available. Users can display energy or intensity ordered tables of gamma-rays, K and L x-rays, alpha-particles, and beta endpoints. Spectra of betas and bremsstrahlung, and Auger/conversion electrons can be viewed with an interactive JAVA applet. Decay schemes can be displayed with the JAVA version of Isotope Explorer 3.0. The URL for the Table of Radioactive Isotopes is http://nucleardata.nuclear.lu.se/nucleardata/toi/.

  3. A storage ring for radioactive beams

    SciTech Connect

    Moltz, D.M.

    1994-05-01

    Preliminary ideas are presented for the scientific justification of a storage ring for radioactive beams. This storage ring would be suitable for many nuclear and atomic physics experiments. Ideally, it would be constructed and tested at an existing low-energy heavy-ion facility before relocation to a major radioactive beam facility.

  4. 46 CFR 148.300 - Radioactive materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... radioactive materials defined in 49 CFR 173.403 as Low Specific Activity Material, LSA-1, or Surface Contaminated Object, SCO-1. (b) Skin contact, inhalation or ingestion of dusts generated by Class 7 material... 7 material (radioactive) listed in Table 148.10 of this part must be surveyed after the...

  5. 46 CFR 148.300 - Radioactive materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... radioactive materials defined in 49 CFR 173.403 as Low Specific Activity Material, LSA-1, or Surface Contaminated Object, SCO-1. (b) Skin contact, inhalation or ingestion of dusts generated by Class 7 material... 7 material (radioactive) listed in Table 148.10 of this part must be surveyed after the...

  6. 46 CFR 148.300 - Radioactive materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... radioactive materials defined in 49 CFR 173.403 as Low Specific Activity Material, LSA-1, or Surface... 46 Shipping 5 2012-10-01 2012-10-01 false Radioactive materials. 148.300 Section 148.300 Shipping... MATERIALS THAT REQUIRE SPECIAL HANDLING Special Requirements for Certain Materials § 148.300...

  7. 46 CFR 148.300 - Radioactive materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... radioactive materials defined in 49 CFR 173.403 as Low Specific Activity Material, LSA-1, or Surface... 46 Shipping 5 2013-10-01 2013-10-01 false Radioactive materials. 148.300 Section 148.300 Shipping... MATERIALS THAT REQUIRE SPECIAL HANDLING Special Requirements for Certain Materials § 148.300...

  8. Diverter assembly for radioactive material

    DOEpatents

    Andrews, K.M.; Starenchak, R.W.

    1988-04-11

    A diverter assembly for diverting a pneumatically conveyed holder for a radioactive material between a central conveying tube and one of a plurality of radially offset conveying tubes includes an airtight container. A diverter tube having an offset end is suitably mounted in the container for rotation. A rotary seal seals one end of the diverter tube during and after rotation of the diverter tube while a spring biased seal seals the other end of the diverter tube which moves between various offset conveying tubes. An indexing device rotatably indexes the diverter tube and this indexing device is driven by a suitable drive. The indexing mechanism is preferably a geneva-type mechanism to provide a locking of the diverter tube in place. 3 figs.

  9. System for radioactive waste cementation

    SciTech Connect

    Dmitriev, S.A.; Barinov, A.S.; Varlakov, A.P.; Volkov, A.S.; Karlin, S.V.

    1995-12-31

    NPP, research reactors and radiochemical enterprises produce a great amount of liquid radioactive waste (LRW). One of the methods of LRW solidification is cementation. The recent investigations demonstrated possible inclusion of sufficient amount of waste in the cement matrix (up to 20--30 mass% on dry residue). In this case the cementation process becomes competitive with bituminization process, where the matrix can include 40--50 mass% and the solidified product volume is equal to the volume, obtained by cementation. Additionally, the cement matrix in contrast with the bituminous one is unburnable. Many countries are investigating the cementation process. The main idea governing technological process is the waste and cement mixing method and type of mixer. In world practice some principal types of cementation systems are used. The paper describes the SIA Radon industrial plant in Moscow.

  10. Microbiological treatment of radioactive wastes

    SciTech Connect

    Francis, A.J.

    1992-12-31

    The ability of microorganisms which are ubiquitous throughout nature to bring about information of organic and inorganic compounds in radioactive wastes has been recognized. Unlike organic contaminants, metals cannot be destroyed, but must be either removed or converted to a stable form. Radionuclides and toxic metals in wastes may be present initially in soluble form or, after disposal may be converted to a soluble form by chemical or microbiological processes. The key microbiological reactions include (i) oxidation/reduction; (ii) change in pH and Eh which affects the valence state and solubility of the metal; (iii) production of sequestering agents; and (iv) bioaccumulation. All of these processes can mobilize or stabilize metals in the environment.

  11. Method for immobilizing radioactive iodine

    DOEpatents

    Babad, Harry; Strachan, Denis M.

    1980-01-01

    Radioactive iodine, present as alkali metal iodides or iodates in an aqueous solution, is incorporated into an inert solid material for long-term storage by adding to the solution a stoichiometric amount with respect to the formation of a sodalite (3M.sub.2 O.3Al.sub.2 O.sub.3. 6SiO.sub.2.2MX, where M=alkali metal; X=I.sup.- or IO.sub.3.sup.-) of an alkali metal, alumina and silica, stirring the solution to form a homogeneous mixture, drying the mixture to form a powder, compacting and sintering the compacted powder at 1073 to 1373 K (800.degree. to 1100.degree. C.) for a time sufficient to form sodalite.

  12. Radioactive liquid waste treatment facility

    SciTech Connect

    Black, R.L.

    1984-07-01

    The Radioactive Liquid Waste Treatment Facility (RLWTF) at Argonne National Laboratory-West (ANL-W) in Idaho provides improved treatment for low-level aqueous waste compared to conventional systems. A unique, patented evaporated system is used in the RLWTF. SHADE (shielded hot air drum evaporator, US Patent No. 4,305,780) is a low-cost disposable unit constructed from standard components and is self-shielded. The results of testing and recent operations indicate that evaporation rates of 2 to 6 gph (8 to 23 L/h) can be achieved with a single unit housed in a standard 30-gal (114-L) drum container. The operating experience has confirmed the design evaporation rate of 60,000 gal (227,000 L) per year, using six SHADE's. 2 references, 2 figures, 2 tables.

  13. Production of high intensity radioactive beams

    SciTech Connect

    Nitschke, J.M.

    1990-04-01

    The production of radioactive nuclear beams world-wide is reviewed. The projectile fragmentation and the ISOL approaches are discussed in detail, and the luminosity parameter is used throughout to compare different production methods. In the ISOL approach a thin and a thick target option are distinguished. The role of storage rings in radioactive beam research is evaluated. It is concluded that radioactive beams produced by the projectile fragmentation and the ISOL methods have complementary characteristics and can serve to answer different scientific questions. The decision which kind of facility to build has to depend on the significance and breadth of these questions. Finally a facility for producing a high intensity radioactive beams near the Coulomb barrier is proposed, with an expected luminosity of {approximately}10{sup 39} cm{sup {minus}2} s{sup {minus}1}, which would yield radioactive beams in excess of 10{sup 11} s{sup {minus}1}. 9 refs., 3 figs., 7 tabs.

  14. Apparatus and method for radioactive waste screening

    DOEpatents

    Akers, Douglas W.; Roybal, Lyle G.; Salomon, Hopi; Williams, Charles Leroy

    2012-09-04

    An apparatus and method relating to screening radioactive waste are disclosed for ensuring that at least one calculated parameter for the measurement data of a sample falls within a range between an upper limit and a lower limit prior to the sample being packaged for disposal. The apparatus includes a radiation detector configured for detecting radioactivity and radionuclide content of the of the sample of radioactive waste and generating measurement data in response thereto, and a collimator including at least one aperture to direct a field of view of the radiation detector. The method includes measuring a radioactive content of a sample, and calculating one or more parameters from the radioactive content of the sample.

  15. The safe disposal of radioactive wastes

    PubMed Central

    Kenny, A. W.

    1956-01-01

    A comprehensive review is given of the principles and problems involved in the safe disposal of radioactive wastes. The first part is devoted to a study of the basic facts of radioactivity and of nuclear fission, the characteristics of radioisotopes, the effects of ionizing radiations, and the maximum permissible levels of radioactivity for workers and for the general public. In the second part, the author describes the different types of radioactive waste—reactor wastes and wastes arising from the use of radioisotopes in hospitals and in industry—and discusses the application of the maximum permissible levels of radioactivity to their disposal and treatment, illustrating his discussion with an account of the methods practised at the principal atomic energy establishments. PMID:13374534

  16. Radioactive nuclear beams. Proceedings. 4th International Conference on Radioactive Nuclear Beams (RNB 4), Omiya (Japan), 3 - 7 Jun 1996.

    NASA Astrophysics Data System (ADS)

    1997-04-01

    The following topics were dealt with: radioactive nuclear beam facilities, nuclear astrophysics with radioactive nuclear beams, structure of light exotic nuclei, structure of medium and heavy exotic nuclei, microscopic approach to exotic nuclei, application of radioactive nuclear beams.

  17. Influence of Radioactivity on Surface Interaction Forces

    SciTech Connect

    Walker, Mark E; McFarlane, Joanna; Glasgow, David C; Chung, Eunhyea; Taboada Serrano, Patricia L; Yiacoumi, Sotira; Tsouris, Costas

    2010-01-01

    Although some differences have been observed, the transport behavior of radioactive aerosol particles has often been assumed to be analogous to the behavior of nonradioactive aerosols in dispersion models. However, radioactive particles can become electrostatically charged as a result of the decay process. Theories have been proposed to describe this self-charging phenomenon, which may have a significant effect on how these particles interact with one another and with charged surfaces in the environment. In this study, atomic force microscopy (AFM) was employed to quantify surface forces between a particle and a planar surface and to compare measurements with and without the involvement of radioactivity. The main objective of this work is to assess directly the effects of radioactivity on the surface interactions of radioactive aerosols via the measurement of the adhesion force. The adhesion force between a silicon nitride AFM tip and an activated gold substrate was measured so that any possible effects due to radioactivity could be observed. The adhesion force between the tip and the gold surface increased significantly when the gold substrate (25 mm{sup 2} surface area) was activated to a level of approximately 0.6 mCi. The results of this investigation will prompt further work into the effects of radioactivity in particle-surface interactions.

  18. A radioactive metal processing industry perspective source.

    PubMed

    Johnson, A

    2006-11-01

    The current U.S. economic environment for the disposition of radioactive waste, including very-low-activity metals, is currently experiencing relatively low radioactive disposal costs and readily available disposal space. Despite the recent market increase in demand for recycled scrap metal commodities, there is still little change in the behavior of the nuclear industry (including radioactive waste processors and radioactive scrap metal recyclers) to pursue the recycling of potentially contaminated scrap metal. The relatively low cost of traditional radioactive waste disposal combined with the perceived risks associated with recycling of previously contaminated metals means that most U.S. radioactive facility managers and stakeholders will elect not to recycle. Current technology exists and precedence has been set for prescreening (by means of bulk radioactive assay techniques) scrap metal that is not contaminated and diverting it to industrial landfills for disposal. Other processes also allow some radiologically contaminated metals to be melted and recast into products with low, but acceptable, activity levels for restricted use in the nuclear industry. A new concept is being considered that would create a centralized licensed facility for the process and disposition of "very-low-activity" metals for "directed first use." The advantages to this type of approach would include a standardized method for licensing the clearance process. PMID:17033461

  19. The changing face of radioactivity in steel

    SciTech Connect

    LaMastra, A.

    1995-07-01

    The question of radioactivity in iron and steel is a matter of definition and limits of detectability. A broad statement could be made that all steel that started with blast furnace iron is radioactive. This statement is not due to the practice of using wear-indication sources in the refractory of blast furnaces. Rather, it is because of the nature of the blast furnace process. Air contains radioactivity. Blowing copious quantities of air through a blast furnace introduces a very low level of radioactivity into the process. Some of the radioactivity will be tied up in the slag or become oxidized, but a small portion will become incorporated in the hot metal. Normally, this trivial level of contamination is not of concern because it carries no consequence and is detectable only by the most sensitive laboratory detection systems. For nearly 40 years, few people paid any attention to the topic of radioactivity in steel. However, that changed in Feb. 1983, when Auburn Steel had the unfortunate occasion to melt a radioactive source in their electric furnace. Since that time, there has been a total of 18 confirmed meltings at metal smelters within the US. The problem of melting radioactive sources in metal smelting plants appears to be increasing. It is not known if a trend is developing or if 1992/1993 are random anomalies. Based on past incidents, the difficulty of finding heavily shielded sources in scrap and the likelihood of more gaging devices being lost, steelmaking management must evaluate the importance of achieving high sensitivity. At the same time, management must also realize that the systems will be detecting more commodities and scrap loads that were heretofore not radioactive. That will have an impact on available manpower, traffic control and the timeliness of scrap deliveries.

  20. [CME: Radioactive iodine therapy in thyroid cancer].

    PubMed

    Steinert, Hans C; Aberle, Susanne

    2015-11-11

    Differentiated thyroid carcinomas represent about 90% of all thyroid tumors and are divided in papillary and follicular carcinomas. Their prognosis is good, however, recurrences are not rare. Their ability to accumulate iodine is used for the radioactive iodine treatment. The aim of the postoperative radioactive iodine ablation therapy is the complete elimination of remnant thyroid cells and sensitive staging (Fig. 1). The recurrence rate decreases after a complete thyroid ablation. Furthermore, thyroglobulin can be used as a sensitive tumor marker. Radioactive iodine treatment by itself describes the therapy of metastases. An exception is the papillary microcarcinoma, which in general is treated by a lobectomy alone. PMID:26558927

  1. Applied Radioactivity for Tracing Environmental Transport

    SciTech Connect

    Lisa Karam; Zhichao Lin; Ciara McMahon; Leticia Pibida; Michael Unterweger; Zhongyu Wu

    2000-11-12

    Despite the rhetoric, radioactivity has been and remains a constant in human existence. Naturally occurring species and those introduced by human activity permeate sea, land, and air, and their presence provides science with opportunities to follow events otherwise inaccessible or unquantifiable. The use of radioactivity to ascertain geologic timescales and to monitor atmospheric and oceanic movements and its use in nuclear medicine and as tracers for environmental contamination have required the development and employment of a variety of measurement techniques. Of particular interest has been the determination of low-level and ultralow-level amounts of radioactivity in a variety of complex matrices and the differentiation between naturally occurring and anthropogenic species.

  2. Evaluation of Terrorist Interest in Radioactive Wastes

    SciTech Connect

    McFee, J.N.; Langsted, J.M.; Young, M.E.; Day, J.E.

    2006-07-01

    Since September 11, 2001, intelligence gathered from Al Qaeda training camps in Afghanistan, and the ensuing terrorist activities, indicates nuclear material security concerns are valid. This paper reviews available information on sealed radioactive sources thought to be of interest to terrorists, and then examines typical wastes generated during environmental management activities to compare their comparative 'attractiveness' for terrorist diversion. Sealed radioactive sources have been evaluated in numerous studies to assess their security and attractiveness for use as a terrorist weapon. The studies conclude that tens of thousands of curies in sealed radioactive sources are available for potential use in a terrorist attack. This risk is mitigated by international efforts to find lost and abandoned sources and bring them under adequate security. However, radioactive waste has not received the same level of scrutiny to ensure security. This paper summarizes the activity and nature of radioactive sources potentially available to international terrorists. The paper then estimates radiation doses from use of radioactive sources as well as typical environmental restoration or decontamination and decommissioning wastes in a radioactive dispersal device (RDD) attack. These calculated doses indicate that radioactive wastes are, as expected, much less of a health risk than radioactive sources. The difference in radiation doses from wastes used in an RDD are four to nine orders of magnitude less than from sealed sources. We then review the International Atomic Energy Agency (IAEA) definition of 'dangerous source' in an adjusted comparison to common radioactive waste shipments generated in environmental management activities. The highest waste dispersion was found to meet only category 1-3.2 of the five step IAEA scale. A category '3' source by the IAEA standard 'is extremely unlikely, to cause injury to a person in the immediate vicinity'. The obvious conclusion of the analysis is that environmental management generated radioactive wastes have substantially less impact than radioactive sources if dispersed by terrorist-induced explosion or fire. From a health standpoint, the impact is very small. However, there is no basis to conclude that wastes are totally unattractive for use in a disruptive or economic damage event. Waste managers should be cognizant of this potential and take measures to ensure security of stored waste and waste shipments. (authors)

  3. Science with radioactive beams: the alchemist's dream

    NASA Astrophysics Data System (ADS)

    Gelletly, W.

    2001-05-01

    Nuclear science is being transformed by a new capacity to create beams of radioactive nuclei. Until now all of our knowledge of nuclear physics and the applications which flow from it has been derived from studies of radioactive decay and nuclear reactions induced by beams of the 283 stable or long-lived nuclear species we can find on Earth. Here we describe first how beams of radioactive nuclei can be created. The present status of nuclear physics is then reviewed before potential applications to nuclear physics, nuclear astrophysics, materials science, bio-medical, and environmental studies are described.

  4. Radioactive anomaly discrimination from spectral ratios

    SciTech Connect

    Maniscalco, James; Sjoden, Glenn; Chapman, Mac Clements

    2013-08-20

    A method for discriminating a radioactive anomaly from naturally occurring radioactive materials includes detecting a first number of gamma photons having energies in a first range of energy values within a predetermined period of time and detecting a second number of gamma photons having energies in a second range of energy values within the predetermined period of time. The method further includes determining, in a controller, a ratio of the first number of gamma photons having energies in the first range and the second number of gamma photons having energies in the second range, and determining that a radioactive anomaly is present when the ratio exceeds a threshold value.

  5. Monitoring radioactive contamination by hyperspectral lidar

    NASA Astrophysics Data System (ADS)

    Grishkanich, A. S.; Bespalov, V. G.; Vasiev, S. K.; Gusarov, A. S.; Kascheev, S. V.; Elizarov, V. V.; Zhevlakov, A. P.

    2005-05-01

    There are already significant amounts of hazardous radioactive substances in the world. It, potentially, leads to a major damage and contamination of large areas. Laser sensing can serve as a highly effective method of searching and monitoring of radioactive contamination. We developed a laser system to detect accidental leakage of radioactive materials. Methods of fluorescence spectroscopy and Raman spectroscopy allow to detect a concentration of uranyl U235O2 and U238O2 at 500 ppb, and Sr90 and Cs137 at the level of 1 ppm at 100 m distance from the object.

  6. The Discovery of Artificial Radioactivity

    NASA Astrophysics Data System (ADS)

    Guerra, Francesco; Leone, Matteo; Robotti, Nadia

    2012-03-01

    We reconstruct Frédéric Joliot and Irène Curie's discovery of artificial radioactivity in January 1934 based in part on documents preserved in the Joliot-Curie Archives in Paris, France. We argue that their discovery followed from the convergence of two parallel lines of research, on the neutron and on the positron, that were focused on a well-defined experimental problem, the nuclear transmutation of aluminum and other light elements. We suggest that a key role was played by a suggestion that Francis Perrin made at the seventh Solvay Conference at the end of October 1933, that the alpha-particle bombardment of aluminum produces an intermediate unstable isotope of phosphorus, which then decays by positron emission. We also suggest that a further idea that Perrin published in December 1933, and the pioneering theory of beta decay that Enrico Fermi also first published in December 1933, established a new theoretical framework that stimulated Joliot to resume the researches that he and Curie had interrupted after the Solvay Conference, now for the first time using a Geiger-Müller counter to detect the positrons emitted when he bombarded aluminum with polonium alpha particles.

  7. RADIOACTIVITY STANDARDS DISTRIBUTION PROGRAM, 1978-1979

    EPA Science Inventory

    A program for the distribution of calibrated radioactive samples, as one function of EPA's quality assurance program for environmental radiation measurements, is described. Included is a discussion of the objectives of the distribution program and a description of the preparation...

  8. Issues of natural radioactivity in phosphates

    SciTech Connect

    Schnug, E.; Haneklaus, S.; Schnier, C.; Scholten, L.C.

    1996-12-31

    The fertilization of phosphorus (P) fertilizers is essential in agricultural production, but phosphates contain in dependence on their origin different amounts of trace elements. The problem of cadmium (Cd) loads and other heavy metals is well known. However, only a limited number of investigations examined the contamination of phosphates with the two heaviest metals, uranium (U) and thorium (Th), which are radioactive. Also potassium (K) is lightly radioactive. Measurements are done n the radioactivity content of phosphates, P fertilizers and soils. The radiation doses to workers and public as well as possible contamination of soils from phosphate rock or fertilizer caused by these elements or their daughter products is of interest with regard to radiation protection. The use of P fertilizers is necessary for a sustainable agriculture, but it involves radioactive contamination of soils. The consequences of the use of P fertilizers is discussed, also with regard to existing and proposed legislation. 11 refs., 2 figs., 7 tabs.

  9. Radioactive Dating: A Method for Geochronology.

    ERIC Educational Resources Information Center

    Rowe, M. W.

    1985-01-01

    Gives historical background on the discovery of natural radiation and discusses various techniques for using knowledge of radiochemistry in geochronological studies. Indicates that of these radioactive techniques, Potassium-40/Argon-40 dating is used most often. (JN)

  10. Computer Model Buildings Contaminated with Radioactive Material

    Energy Science and Technology Software Center (ESTSC)

    1998-05-19

    The RESRAD-BUILD computer code is a pathway analysis model designed to evaluate the potential radiological dose incurred by an individual who works or lives in a building contaminated with radioactive material.

  11. Radioactivity in man: levels, effects and unknowns

    SciTech Connect

    Rundo, J.

    1980-01-01

    The report discusses the potential for significant human exposure to internal radiation. Sources of radiation considered include background radiation, fallout, reactor accidents, radioactive waste, and occupational exposure to various radioisotopes. (ACR)

  12. Radioactive materials shipping cask anticontamination enclosure

    DOEpatents

    Belmonte, Mark S. (Irwin, PA); Davis, James H. (Pittsburgh, PA); Williams, David A. (Pittsburgh, PA)

    1982-01-01

    An anticontamination device for use in storing shipping casks for radioactive materials comprising (1) a seal plate assembly; (2) a double-layer plastic bag; and (3) a water management system or means for water management.

  13. Overflow of Radioactive Water from K Basins

    SciTech Connect

    RITTMANN, P.D.

    1999-10-06

    This report documents the dose calculations for the postulated K Basin overflow accident using current methods to model the environmental doses for radioactive releases into the Columbia River and the air.

  14. Principles for Sampling Airborne Radioactivity from Stacks

    SciTech Connect

    Glissmeyer, John A.

    2010-10-18

    This book chapter describes the special processes involved in sampling the airborne effluents from nuclear faciities. The title of the book is Radioactive Air Sampling Methods. The abstract for this chapter was cleared as PNNL-SA-45941.

  15. Vitrification of hazardous and radioactive wastes

    SciTech Connect

    Bickford, D.F.; Schumacher, R.

    1995-12-31

    Vitrification offers many attractive waste stabilization options. Versatility of waste compositions, as well as the inherent durability of a glass waste form, have made vitrification the treatment of choice for high-level radioactive wastes. Adapting the technology to other hazardous and radioactive waste streams will provide an environmentally acceptable solution to many of the waste challenges that face the public today. This document reviews various types and technologies involved in vitrification.

  16. Radioactive waste disposal: An environmental perspective

    SciTech Connect

    Not Available

    1994-08-01

    There are five general categories of radioactive waste: (1) spent nuclear fuel from nuclear reactors and high-level waste from the reprocessing of spent nuclear fuel, (2) transuranic waste mainly from defense programs, (3) uranium mill tailings from the mining and milling of uranium ore, (4) low-level waste, and (5) naturally occurring and acclerator-produced radioactive materials. The booklet describes the different categories of waste, discusses disposal practices for each type, and describes the way they are regulated.

  17. Rheology Modifiers for Radioactive Waste Slurries

    SciTech Connect

    Calloway, T.B. Jr.

    2003-02-19

    The goals of this study were to determine if trace levels of chemical additives could be used to reduce the rheological characteristics of radioactive waste slurries, identify potential chemical additives for this work and future testing, test a limited set of chemical additive candidates on simulated radioactive wastes, and develop advanced techniques to visualize the internal slurry structure and particle-particle interaction within the slurry.

  18. Transport of Radioactive Material by Alpha Recoil

    SciTech Connect

    Icenhour, A.S.

    2005-05-19

    The movement of high-specific-activity radioactive particles (i.e., alpha recoil) has been observed and studied since the early 1900s. These studies have been motivated by concerns about containment of radioactivity and the protection of human health. Additionally, studies have investigated the potential advantage of alpha recoil to effect separations of various isotopes. This report provides a review of the observations and results of a number of the studies.

  19. Tokai Radioactive Ion Accelerator Complex (TRIAC)

    NASA Astrophysics Data System (ADS)

    Watanabe, Y. X.; Arai, S.; Arakaki, Y.; Fuchi, Y.; Hirayama, Y.; Imai, N.; Ishiyama, H.; Jeong, S. C.; Kawakami, H.; Miyatake, H.; Niki, K.; Nomura, T.; Okada, M.; Oyaizu, M.; Tanaka, M. H.; Tomizawa, M.; Yoshikawa, N.; Abe, S.; Hanashima, S.; Hashimoto, T.; Ichikawa, S.; Ikezoe, H.; Ishii, T.; Ishizaki, N.; Kabumoto, H.; Katayama, I.; Koizumi, M.; Matsuda, M.; Mitsuoka, S.; Nakanoya, T.; Nishio, K.; Ohuchi, I.; Osa, A.; Sato, T. K.; Takeuchi, S.; Tayama, H.; Tsukihashi, Y.

    2007-11-01

    An ISOL-based radioactive nuclear beam (RNB) facility, Tokai Radioactive Ion Accelerator Complex (TRIAC), has been jointly developed by High Energy Accelerator Research Organization (KEK) and Japan Atomic Energy Agency (JAEA). The facility started to supply RNBs for experiments in 2005 and RNBs including fission fragments with energies up to 1.1MeV/A are available in the present. Several experimental studies were performed successfully using 8Li beams with various energies.

  20. Salivary gland dysfunction following radioactive iodine therapy

    SciTech Connect

    Wiesenfeld, D.; Webster, G.; Cameron, F.; Ferguson, M.M.; MacFadyen, E.E.; MacFarlane, T.W.

    1983-02-01

    Radioactive iodine is used extensively for the treatment of thyrotoxicosis and thyroid carcinoma. Iodine is actively taken up by the salivary glands and, following its use, salivary dysfunction may result as a consequence of radiation damage. The literature is reviewed and a case is reported in which a patient presented with a significant increase in caries rate attributed to salivary dysfunction following radioactive iodine therapy for a thyroid carcinoma.

  1. Liquid radioactive waste subsystem design description

    SciTech Connect

    1986-06-01

    The Liquid Radioactive Waste Subsystem provides a reliable system to safely control liquid waste radiation and to collect, process, and dispose of all radioactive liquid waste without impairing plant operation. Liquid waste is stored in radwaste receiver tanks and is processed through demineralizers and temporarily stored in test tanks prior to sampling and discharge. Radwastes unsuitable for discharge are transferred to the Solid Radwaste System.

  2. 10 CFR 835.1201 - Sealed radioactive source control.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Sealed radioactive source control. 835.1201 Section 835.1201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control 835.1201 Sealed radioactive source control. Sealed radioactive sources shall be used, handled,...

  3. 10 CFR 835.1202 - Accountable sealed radioactive sources.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Accountable sealed radioactive sources. 835.1202 Section 835.1202 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control 835.1202 Accountable sealed radioactive sources. (a) Each accountable sealed radioactive...

  4. 10 CFR 835.1202 - Accountable sealed radioactive sources.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Accountable sealed radioactive sources. 835.1202 Section 835.1202 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control 835.1202 Accountable sealed radioactive sources. (a) Each accountable sealed radioactive...

  5. 10 CFR 835.1201 - Sealed radioactive source control.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Sealed radioactive source control. 835.1201 Section 835.1201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control 835.1201 Sealed radioactive source control. Sealed radioactive sources shall be used, handled,...

  6. 10 CFR 835.1201 - Sealed radioactive source control.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Sealed radioactive source control. 835.1201 Section 835.1201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control 835.1201 Sealed radioactive source control. Sealed radioactive sources shall be used, handled,...

  7. 10 CFR 835.1202 - Accountable sealed radioactive sources.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Accountable sealed radioactive sources. 835.1202 Section 835.1202 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control 835.1202 Accountable sealed radioactive sources. (a) Each accountable sealed radioactive...

  8. 10 CFR 835.1202 - Accountable sealed radioactive sources.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Accountable sealed radioactive sources. 835.1202 Section 835.1202 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control 835.1202 Accountable sealed radioactive sources. (a) Each accountable sealed radioactive...

  9. 10 CFR 835.1201 - Sealed radioactive source control.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Sealed radioactive source control. 835.1201 Section 835.1201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control 835.1201 Sealed radioactive source control. Sealed radioactive sources shall be used, handled,...

  10. 10 CFR 835.1202 - Accountable sealed radioactive sources.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Accountable sealed radioactive sources. 835.1202 Section 835.1202 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control 835.1202 Accountable sealed radioactive sources. (a) Each accountable sealed radioactive...

  11. 10 CFR 835.1201 - Sealed radioactive source control.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Sealed radioactive source control. 835.1201 Section 835.1201 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Sealed Radioactive Source Control 835.1201 Sealed radioactive source control. Sealed radioactive sources shall be used, handled,...

  12. Public involvement in radioactive waste management decisions

    SciTech Connect

    1994-04-01

    Current repository siting efforts focus on Yucca Mountain, Nevada, where DOE`s Office of Civilian Radioactive Waste Management (OCRWM) is conducting exploratory studies to determine if the site is suitable. The state of Nevada has resisted these efforts: it has denied permits, brought suit against DOE, and publicly denounced the federal government`s decision to study Yucca Mountain. The state`s opposition reflects public opinion in Nevada, and has considerably slowed DOE`s progress in studying the site. The Yucca Mountain controversy demonstrates the importance of understanding public attitudes and their potential influence as DOE develops a program to manage radioactive waste. The strength and nature of Nevada`s opposition -- its ability to thwart if not outright derail DOE`s activities -- indicate a need to develop alternative methods for making decisions that affect the public. This report analyzes public participation as a key component of this openness, one that provides a means of garnering acceptance of, or reducing public opposition to, DOE`s radioactive waste management activities, including facility siting and transportation. The first section, Public Perceptions: Attitudes, Trust, and Theory, reviews the risk-perception literature to identify how the public perceives the risks associated with radioactivity. DOE and the Public discusses DOE`s low level of credibility among the general public as the product, in part, of the department`s past actions. This section looks at the three components of the radioactive waste management program -- disposal, storage, and transportation -- and the different ways DOE has approached the problem of public confidence in each case. Midwestern Radioactive Waste Management Histories focuses on selected Midwestern facility-siting and transportation activities involving radioactive materials.

  13. CHAPTER 5-RADIOACTIVE WASTE MANAGEMENT

    SciTech Connect

    Marra, J.

    2010-05-05

    The ore pitchblende was discovered in the 1750's near Joachimstal in what is now the Czech Republic. Used as a colorant in glazes, uranium was identified in 1789 as the active ingredient by chemist Martin Klaproth. In 1896, French physicist Henri Becquerel studied uranium minerals as part of his investigations into the phenomenon of fluorescence. He discovered a strange energy emanating from the material which he dubbed 'rayons uranique.' Unable to explain the origins of this energy, he set the problem aside. About two years later, a young Polish graduate student was looking for a project for her dissertation. Marie Sklodowska Curie, working with her husband Pierre, picked up on Becquerel's work and, in the course of seeking out more information on uranium, discovered two new elements (polonium and radium) which exhibited the same phenomenon, but were even more powerful. The Curies recognized the energy, which they now called 'radioactivity,' as something very new, requiring a new interpretation, new science. This discovery led to what some view as the 'golden age of nuclear science' (1895-1945) when countries throughout Europe devoted large resources to understand the properties and potential of this material. By World War II, the potential to harness this energy for a destructive device had been recognized and by 1939, Otto Hahn and Fritz Strassman showed that fission not only released a lot of energy but that it also released additional neutrons which could cause fission in other uranium nuclei leading to a self-sustaining chain reaction and an enormous release of energy. This suggestion was soon confirmed experimentally by other scientists and the race to develop an atomic bomb was on. The rest of the development history which lead to the bombing of Hiroshima and Nagasaki in 1945 is well chronicled. After World War II, development of more powerful weapons systems by the United States and the Soviet Union continued to advance nuclear science. It was this defense application that formed the basis for the commercial nuclear power industry.

  14. Volumetric Radioactivity Viewed as Surface Radioactivity for Free Release Assessment Purposes

    SciTech Connect

    Boettinger, W.L.

    1998-07-08

    As a part of the SRS Beneficial Reuse Program, stainless steel radioactive scrap metal is melted, pour into ingots, and roll into sheets. The sheets are then fabricated into boxes and barrels for beneficial reuse. The melting activity is a partial decontamination process. Certain isotopes separate from the melted steel, while others stay in solution. Cobalt-60 is the primary constituent, which remains in solution, and becomes the major contributor to the volumetric radioactivity of the finished products (boxes and barrels). There is currently no ``de minimis`` free release level for volumetrically radioactive material. However, under certain circumstances, pathway analysis can be used (and have been used) to free release volumetrically radioactive material. This paper presents an analysis using empirical data derived from over sixty ``melts``, to demonstrate that the implied surface radioactivity for specific beneficial reuse products is within free release limit. The approach can be applied to other recycled metal products.

  15. Radioactive waste management in a hospital.

    PubMed

    Khan, Shoukat; Syed, At; Ahmad, Reyaz; Rather, Tanveer A; Ajaz, M; Jan, Fa

    2010-01-01

    Most of the tertiary care hospitals use radioisotopes for diagnostic and therapeutic applications. Safe disposal of the radioactive waste is a vital component of the overall management of the hospital waste. An important objective in radioactive waste management is to ensure that the radiation exposure to an individual (Public, Radiation worker, Patient) and the environment does not exceed the prescribed safe limits. Disposal of Radioactive waste in public domain is undertaken in accordance with the Atomic Energy (Safe disposal of radioactive waste) rules of 1987 promulgated by the Indian Central Government Atomic Energy Act 1962. Any prospective plan of a hospital that intends using radioisotopes for diagnostic and therapeutic procedures needs to have sufficient infrastructural and manpower resources to keep its ambient radiation levels within specified safe limits. Regular monitoring of hospital area and radiation workers is mandatory to assess the quality of radiation safety. Records should be maintained to identify the quality and quantity of radioactive waste generated and the mode of its disposal. Radiation Safety officer plays a key role in the waste disposal operations. PMID:21475524

  16. Environmental radioactivity in the Arctic, Antarctic

    SciTech Connect

    Palmer, H.

    1993-12-01

    This conference on radioactivity in the Arctic and Antarctic was held in Kirkenes, Norway and sponsored by the Norwegian Radiation Protection Authority and the Department of Radiation Physics, Sweden's University of Lund. Radioactivity in the Arctic is the result of both natural phenomena and human activities. Natural or background radioactivity is a result of the breakdown and erosion of rocks that contain naturally radioactive minerals. But the levels introduced by dumping, weapons testing, and industrial activities far exceed such natural levels. Conference delegates cited such contamination sources as: Chernobyl's nuclear reactor accident; Wastes from fuel reprocessing plants at Sellafield (UK) and La Hague (France); Weapons testing in and around Novaya Zemlya; Ocean dumping of reactors, waste containers, and liquid wastes; Runoff from watersheds containing soil and organic material contaminated by atmospheric fallout; Atmospheric fallout from decades of weapons tests by various nations; and, Accidents involving nuclear submarines. The potential for increased radioactive pollution is of great concern and these questions were addressed by several speakers.

  17. Radioactive Waste Management in A Hospital

    PubMed Central

    Khan, Shoukat; Syed, AT; Ahmad, Reyaz; Rather, Tanveer A.; Ajaz, M; Jan, FA

    2010-01-01

    Most of the tertiary care hospitals use radioisotopes for diagnostic and therapeutic applications. Safe disposal of the radioactive waste is a vital component of the overall management of the hospital waste. An important objective in radioactive waste management is to ensure that the radiation exposure to an individual (Public, Radiation worker, Patient) and the environment does not exceed the prescribed safe limits. Disposal of Radioactive waste in public domain is undertaken in accordance with the Atomic Energy (Safe disposal of radioactive waste) rules of 1987 promulgated by the Indian Central Government Atomic Energy Act 1962. Any prospective plan of a hospital that intends using radioisotopes for diagnostic and therapeutic procedures needs to have sufficient infrastructural and manpower resources to keep its ambient radiation levels within specified safe limits. Regular monitoring of hospital area and radiation workers is mandatory to assess the quality of radiation safety. Records should be maintained to identify the quality and quantity of radioactive waste generated and the mode of its disposal. Radiation Safety officer plays a key role in the waste disposal operations. PMID:21475524

  18. Pulmonary toxicity of stable and radioactive lanthanides.

    PubMed

    Haley, P J

    1991-12-01

    The pulmonary toxicity of inhaled lanthanides has been the subject of debate. In question have been the relative contributions of radioactive vs. stable elements in the development of lanthanide-associated progressive pulmonary interstitial fibrosis. The central question of this debate is: Are lanthanide dusts that are devoid of radioactive contaminants capable of producing progressive pulmonary disease, or are lanthanide-induced lesions more appropriately termed "benign pneumoconioses"? This paper examines the epidemiologic and experimental record in order to answer the above question. It is clear from the available data that significant pathogenic potential of inhaled lanthanides exists and is related to the type and physicochemical form of the material inhaled and to the dose and duration of exposure. Contamination of the dust with radioactive materials may accelerate and enhance the pathologic response, depending on the form and dose of radioactivity encountered. Nevertheless, there is little evidence to suggest that the level of radioactive contamination of occupationally encountered lanthanide dusts is sufficient to be included as a risk factor for pulmonary disease. Thus, the pulmonary syndrome induced by stable rare earths includes progressive pulmonary fibrosis and should not be referred to as "benign pneumoconiosis." PMID:1955325

  19. PWR-GALE. PWR Effluent Radioactivity Releases

    SciTech Connect

    Willis, C.A.

    1992-01-13

    PWR-GALE calculates the expected annual releases of radioactive materials in gaseous and liquid effluents from pressurized light water reactors (PWRs). The calculations are based on data generated from operating reactors, field and laboratory tests, and plant-specific considerations incorporated to reduce the quantity of radioactive materials that may be released to the environment during normal operation including anticipated operational occurrences. PWR-GALE consists of two program, PGALEGS and PGALELQ. PGALEGS calculates the releases of radioactive materials (noble gases, radioactive particulates, carbon-14, tritium, argon-41, and iodine) in gaseous effluents from the waste gas processing system, steam generator blowdown system, condenser air ejector exhaust, containment purge exhaust, ventilation exhaust air from the auxiliary and turbine buildings and the spent fuel area, and steam leakage from the secondary system. PGALELQ calculates the releases of radioactive materials in liquid effluents from processed water generated from the boron recovery system to maintain plant water balance or for tritium control; processed liquid waste discharged from the waste systems, steam generator blowdown treatment system, and that discharged from the chemical waste and condensate demineralizer regeneration system; liquid waste discharged from the turbine building floor drain sumps; and detergent waste.

  20. Laser decontamination of the radioactive lightning rods

    NASA Astrophysics Data System (ADS)

    Potiens, A. J.; Dellamano, J. C.; Vicente, R.; Raele, M. P.; Wetter, N. U.; Landulfo, E.

    2014-02-01

    Between 1970 and 1980 Brazil experienced a significant market for radioactive lightning rods (RLR). The device consists of an air terminal with one or more sources of americium-241 attached to it. The sources were used to ionize the air around them and to increase the attraction of atmospheric discharges. Because of their ineffectiveness, the nuclear regulatory authority in Brazil suspended the license for manufacturing, commerce and installation of RLR in 1989, and determined that the replaced RLR were to be collected to a centralized radioactive waste management facility for treatment. The first step for RLR treatment is to remove the radioactive sources. Though they can be easily removed, some contaminations are found all over the remaining metal scrap that must decontaminated for release, otherwise it must be treated as radioactive waste. Decontamination using various chemicals has proven to be inefficient and generates large amounts of secondary wastes. This work shows the preliminary results of the decontamination of 241Am-contaminated metal scrap generated in the treatment of radioactive lightning rods applying laser ablation. A Nd:YAG nanoseconds laser was used with 300 mJ energy leaving only a small amount of secondary waste to be treated.

  1. Historical perspectives on environmental radioactivity measurements

    SciTech Connect

    Sedlet, J.

    1987-01-01

    This paper reviews the origins of environmental radioactivity measurements, their purposes, and the development of the techniques used. It is useful to classify radioactivity as to its sources and to classify the measurements into two time groups. Four sources of radioactivity exist: (a) the primordial radionuclides, (b) cosmic radiation, (c) cosmogenic radionuclides, and (d) man-made radionuclides. Since the importance of the measurements increased greatly with the development of nuclear weapons, the measurements conveniently divide into those made before and after the first nuclear detonation in 1945. Since the future has to be predicted from the past, the following observations may be made: (1) mass spectrometry and single-atom counting will replace decay counting when the best sensitivity is needed. (2) Lower and lower levels of radioactivity will become both important and possible to measure. (3) Physical and chemical forms of environmental nuclides will be desired in addition to the amount of radioactivity. (4) The energy spectrum of environmental beta and gamma radiation will be desired in addition to the total amount of such radiation.

  2. Wide range radioactive gas concentration detector

    DOEpatents

    Anderson, David F. (Los Alamos, NM)

    1984-01-01

    A wide range radioactive gas concentration detector and monitor which is capable of measuring radioactive gas concentrations over a range of eight orders of magnitude. The device of the present invention is designed to have an ionization chamber which is sufficiently small to give a fast response time for measuring radioactive gases but sufficiently large to provide accurate readings at low concentration levels. Closely spaced parallel plate grids provide a uniform electric field in the active region to improve the accuracy of measurements and reduce ion migration time so as to virtually eliminate errors due to ion recombination. The parallel plate grids are fabricated with a minimal surface area to reduce the effects of contamination resulting from absorption of contaminating materials on the surface of the grids. Additionally, the ionization chamber wall is spaced a sufficient distance from the active region of the ionization chamber to minimize contamination effects.

  3. Completion of the Radioactive Materials Packaging Handbook

    SciTech Connect

    Shappert, L.B.

    1998-02-01

    The Radioactive Materials Packaging Handbook: Design, Operation and Maintenance, which will serve as a replacement for the Cask Designers Guide (Shappert, 1970), has now been completed and submitted to the Oak Ridge National Laboratory (ORNL) electronics publishing group for layout and printing; it is scheduled to be printed in late spring 1998. The Handbook, written by experts in their particular fields, is a compilation of technical chapters that address the design aspects of a package intended for transporting radioactive material in normal commerce; it was prepared under the direction of M. E. Wangler of the US Department of Energy (DOE) and is intended to provide a wealth of technical guidance that will give designers a better understanding of the regulatory approval process, preferences of regulators on specific aspects of package design, and the types of analyses that should be considered when designing a package to carry radioactive materials.

  4. Radioactive source security: the cultural challenges.

    PubMed

    Englefield, Chris

    2015-04-01

    Radioactive source security is an essential part of radiation protection. Sources can be abandoned, lost or stolen. If they are stolen, they could be used to cause deliberate harm and the risks are varied and significant. There is a need for a global security protection system and enhanced capability to achieve this. The establishment of radioactive source security requires 'cultural exchanges'. These exchanges include collaboration between: radiation protection specialists and security specialists; the nuclear industry and users of radioactive sources; training providers and regulators/users. This collaboration will facilitate knowledge and experience exchange for the various stakeholder groups, beyond those already provided. This will promote best practice in both physical and information security and heighten security awareness generally. Only if all groups involved are prepared to open their minds to listen to and learn from, each other will a suitable global level of control be achieved. PMID:25377752

  5. Low radioactivity spectral gamma calibration facility

    SciTech Connect

    Mathews, M.A.; Bowman, H.R.; Huang, L., H.; Lavelle, M.J.; Smith, A.R.; Hearst, J.R.; Wollenberg, H.A.; Flexser, S.

    1986-01-01

    A low radioactivity calibration facility has been constructed at the Nevada Test Site (NTS). This facility has four calibration models of natural stone that are 3 ft in diameter and 6 ft long, with a 12 in. cored borehole in the center of each model and a lead-shielded run pipe below each model. These models have been analyzed by laboratory natural gamma ray spectroscopy (NGRS) and neutron activation analysis (NAA) for their K, U, and Th content. Also, 42 other elements were analyzed in the NAA. The /sup 222/Rn emanation data were collected. Calibrating the spectral gamma tool in this low radioactivity calibration facility allows the spectral gamma log to accurately aid in the recognition and mapping of subsurface stratigraphic units and alteration features associated with unusual concentrations of these radioactive elements, such as clay-rich zones.

  6. Radioactivity and electron acceleration in supernova remnants

    SciTech Connect

    Zirakashvili, V. N.; Aharonian, F. A.

    2011-10-15

    We argue that the decays of radioactive nuclei related to {sup 44}Ti and {sup 56}Ni ejected during supernova explosions can provide a vast pool of mildly relativistic positrons and electrons which are further accelerated to ultrarelativistic energies by reverse and forward shocks. This interesting link between two independent processes - the radioactivity and the particle acceleration - can be a clue for solution of the well known theoretical problem of electron injection in supernova remnants. In the case of the brightest radio source Cas A, we demonstrate that the radioactivity can supply adequate number of energetic electrons and positrons for interpretation of observational data provided that they are stochastically preaccelerated in the upstream regions of the forward and reverse shocks.

  7. Radioactive tank waste remediation focus area

    SciTech Connect

    1996-08-01

    EM`s Office of Science and Technology has established the Tank Focus Area (TFA) to manage and carry out an integrated national program of technology development for tank waste remediation. The TFA is responsible for the development, testing, evaluation, and deployment of remediation technologies within a system architecture to characterize, retrieve, treat, concentrate, and dispose of radioactive waste stored in the underground stabilize and close the tanks. The goal is to provide safe and cost-effective solutions that are acceptable to both the public and regulators. Within the DOE complex, 335 underground storage tanks have been used to process and store radioactive and chemical mixed waste generated from weapon materials production and manufacturing. Collectively, thes tanks hold over 90 million gallons of high-level and low-level radioactive liquid waste in sludge, saltcake, and as supernate and vapor. Very little has been treated and/or disposed or in final form.

  8. Type A radioactive liquid sample packaging family

    SciTech Connect

    Edwards, W.S.

    1995-11-01

    Westinghouse Hanford Company (WHC) has developed two packagings that can be used to ship Type A quantities of radioactive liquids. WHC designed these packagings to take advantage of commercially available items where feasible to reduce the overall packaging cost. The Hedgehog packaging can ship up to one liter of Type A radioactive liquid with no shielding and 15 cm of distance between the liquid and the package exterior, or 30 ml of liquid with 3.8 cm of stainless steel shielding and 19 cm of distance between the liquid and the package exterior. The One Liter Shipper can ship up to one liter of Type A radioactive liquid that does not require shielding.

  9. Pump station for radioactive waste water

    DOEpatents

    Whitton, John P.; Klos, Dean M.; Carrara, Danny T.; Minno, John J.

    2003-11-18

    A pump station for transferring radioactive particle containing waste water, includes: (a.) an enclosed sump having a vertically elongated right frusto conical wall surface and a bottom surface and (b.) a submersible volute centrifugal pump having a horizontally rotating impeller and a volute exterior surface. The sump interior surface, the bottom surface and the volute exterior surface are made of stainless steel having a 30 Ra or finer surface finish. A 15 Ra finish has been found to be most cost effective. The pump station is used for transferring waste water, without accumulation of radioactive fines.

  10. Cluster radioactivities of odd-mass nuclei

    NASA Astrophysics Data System (ADS)

    Poenaru, D. N.; Hourani, E.; Greiner, W.

    The partial half-lives of the hypothetical even-even equivalent of an odd-mass nucleus for cluster transitions toward various excited states of the daughter, used as a reference to find the hindrance factor, can be calculated within analytical superasymmetric fission model, by taking into account the angular momentum of the emitted cluster. Detailed tables are presented for 14C radioactivity of 221Fr, 221,223Ra, 225Ac; 24Ne radioactivity of 233U, 231Pa, and 23F decay of 231Pa, showing that, except for 225Ac, the existing experimental evidences, do not exclude (moderate) hindered transitions to the ground states of the daugther nuclei.

  11. Obtaining and Investigating Unconventional Sources of Radioactivity

    NASA Astrophysics Data System (ADS)

    Lapp, David R.

    2010-02-01

    This paper provides examples of naturally radioactive items that are likely to be found in most communities. Additionally, there is information provided on how to acquire many of these items inexpensively. I have found that the presence of these materials in the classroom is not only useful for teaching about nuclear radiation and debunking the "nuclear free" myth, but also for helping students to understand the history of some of the commercial uses of radioactive materials since the early 20th century. Finally, the activity of each source (relative to background radiation) is provided.

  12. Microwave remediation of hazardous and radioactive wastes

    SciTech Connect

    Wicks, G.G.

    2000-04-28

    A team from the Westinghouse Savannah River Technology Center (WSRC - a DOE Laboratory), and the University of Florida (UF - academia), has been active for about a decade in development of microwave technology for specialized waste management applications. This interaction has resulted in the development of unique equipment and uses of microwave energy for a variety of important applications for remediation of hazardous and radioactive wastes. Discussed are results of this unique technology for processing of electronic circuitry and components, medical wastes, discarded tires, and transuranic radioactive wastes.

  13. Technology applications for radioactive waste minimization

    SciTech Connect

    Devgun, J.S.

    1994-07-01

    The nuclear power industry has achieved one of the most successful examples of waste minimization. The annual volume of low-level radioactive waste shipped for disposal per reactor has decreased to approximately one-fifth the volume about a decade ago. In addition, the curie content of the total waste shipped for disposal has decreased. This paper will discuss the regulatory drivers and economic factors for waste minimization and describe the application of technologies for achieving waste minimization for low-level radioactive waste with examples from the nuclear power industry.

  14. Nondestructive measurement of environmental radioactive strontium

    NASA Astrophysics Data System (ADS)

    Saiba, Shuntaro; Okamiya, Tomohiro; Tanaka, Saki; Tanuma, Ryosuke; Totsuka, Yumi; Murata, Jiro

    2014-03-01

    The Fukushima Daiichi nuclear power plant accident was triggered by the 2011 Great East Japan Earthquake. The main radioactivity concerns after the accident are I-131 (half-life: 8.0 days), Cs-134 (2.1 years), Cs-137 (30 years), Sr-89 (51 days), and Sr-90 (29 years). We are aiming to establish a new nondestructive measurement and detection technique that will enable us to realize a quantitative evaluation of strontium radioactivity without chemical separation processing. This technique is needed to detect radiation contained in foods, environmental water, and soil, to prevent us from undesired internal exposure to radiation.

  15. Microwave processing of radioactive materials-I

    SciTech Connect

    White, T.L.; Berry, J.B.

    1989-01-01

    This paper is the first of two papers that reviews the major past and present applications of microwave energy for processing radioactive materials, with particular emphasis on processing radioactive wastes. Microwave heating occurs through the internal friction produced inside a dielectric material when its molecules vibrate in response to an oscillating microwave field. For this presentation, we shall focus on the two FCC-approved microwave frequencies for industrial, scientific, and medical use, 915 and 2450 MHz. Also, because of space limitations, we shall postpone addressing plasma processing of hazardous wastes using microwave energy until a later date. 13 refs., 4 figs.

  16. Radioactive Ion Beam Production Capabilities at the Holifield Radioactive Ion Beam Facility

    SciTech Connect

    Beene, James R; Dowling, Darryl T; Gross, Carl J; Juras, Raymond C; Liu, Yuan; Meigs, Martha J; Mendez, II, Anthony J; Nazarewicz, Witold; Sinclair, John William; Stracener, Daniel W; Tatum, B Alan

    2011-01-01

    The Holifield Radioactive Ion Beam Facility (HRIBF) is a national user facility for research with radioactive ion beams (RIBs) that has been in routine operation since 1996. It is located at Oak Ridge National Laboratory (ORNL) and operated by the ORNL Physics Division. The principal mission of HRIBF is the production of high-quality beams of short-lived radioactive isotopes to support research in nuclear structure physics and nuclear astrophysics. HRIBF is currently unique worldwide in its ability to provide neutron-rich fission fragment beams post-accelerated to energies above the Coulomb barrier for nuclear reactions.

  17. Annual Radioactive Waste Tank Inspection Program - 1998

    SciTech Connect

    McNatt, F.G.

    1999-10-27

    Aqueous radioactive wastes from Savannah River Site separations processes are contained in large underground carbon steel tanks. Inspections made during 1998 to evaluate these vessels and auxiliary appurtenances, along with evaluations based on data accrued by inspections performed since the tanks were constructed, are the subject of this report.

  18. Obtaining and Investigating Unconventional Sources of Radioactivity

    ERIC Educational Resources Information Center

    Lapp, David R.

    2010-01-01

    This paper provides examples of naturally radioactive items that are likely to be found in most communities. Additionally, there is information provided on how to acquire many of these items inexpensively. I have found that the presence of these materials in the classroom is not only useful for teaching about nuclear radiation and debunking the

  19. 49 CFR 172.556 - RADIOACTIVE placard.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... on the RADIOACTIVE placard must be white in the lower portion with a yellow triangle in the upper portion. The base of the yellow triangle must be 29 mm 5 mm (1.1 inches 0.2 inches) above the...

  20. Method for decontamination of radioactive metal surfaces

    DOEpatents

    Bray, L.A.

    1996-08-13

    Disclosed is a method for removing radioactive contaminants from metal surfaces by applying steam containing an inorganic acid and cerium IV. Cerium IV is applied to contaminated metal surfaces by introducing cerium IV in solution into a steam spray directed at contaminated metal surfaces. Cerium IV solution is converted to an essentially atomized or vapor phase by the steam.

  1. Canister arrangement for storing radioactive waste

    DOEpatents

    Lorenzo, Donald K. (Knoxville, TN); Van Cleve, Jr., John E. (Kingston, TN)

    1982-01-01

    The subject invention relates to a canister arrangement for jointly storing high level radioactive chemical waste and metallic waste resulting from the reprocessing of nuclear reactor fuel elements. A cylindrical steel canister is provided with an elongated centrally disposed billet of the metallic waste and the chemical waste in vitreous form is disposed in the annulus surrounding the billet.

  2. Nondestructive assay of boxed radioactive waste

    SciTech Connect

    Gilles, W.P.; Roberts, R.J.; Jasen, W.G.

    1992-12-01

    This paper describes the problems related to the nondestructive assay (NDA) of boxed radioactive waste at the Hanford Site and how Westinghouse Hanford company (WHC) is solving the problems. The waste form and radionuclide content are described. The characteristics of the combined neutron and gamma-based measurement system are described.

  3. High-level radioactive wastes. Supplement 1

    SciTech Connect

    McLaren, L.H.

    1984-09-01

    This bibliography contains information on high-level radioactive wastes included in the Department of Energy's Energy Data Base from August 1982 through December 1983. These citations are to research reports, journal articles, books, patents, theses, and conference papers from worldwide sources. Five indexes, each preceded by a brief description, are provided: Corporate Author, Personal Author, Subject, Contract Number, and Report Number. 1452 citations.

  4. Annual Radioactive Waste Tank Inspection Program - 2000

    SciTech Connect

    West, W.R.

    2001-04-17

    Aqueous radioactive wastes from Savannah River Site (SRS) separations and vitrification processes are contained in large underground carbon steel tanks. Inspections made during 2000 to evaluate these vessels and other waste handling facilities along with evaluations based on data from previous inspections are the subject of this report.

  5. Physics with energetic radioactive ion beams

    SciTech Connect

    Henning, W.F.

    1996-12-31

    Beams of short-lived, unstable nuclei have opened new dimensions in studies of nuclear structure and reactions. Such beams also provide key information on reactions that take place in our sun and other stars. Status and prospects of the physics with energetic radioactive beams are summarized.

  6. Environmental radioactivity studies and regulatory issues.

    PubMed

    Abalkina, I L; Sarkisov, A A; Linge, I I; Kazakov, S V; Panchenko, S V; Savelieva, E A

    2008-11-01

    During the last decades, Russia has developed regulations applying to the territories affected by radioactive contamination. Some regulatory approaches appear to be quite ineffective and contradictory. This paper shows by means of examples the problems and issues associated with some existing situations. A better way for the future is indicated. PMID:18602832

  7. Annual Radioactive Waste Tank Inspection Program 1994

    SciTech Connect

    McNatt, F.G. Sr.

    1995-04-01

    Aqueous radioactive wastes from Savannah River Site (SRS) separations processes are contained in large underground carbon steel tanks. Inspections made during 1994 to evaluate these vessels and evaluations based on data accrued by inspections made since the tanks were constructed are the subject of this report.

  8. A Sensitive Cloud Chamber without Radioactive Sources

    ERIC Educational Resources Information Center

    Zeze, Syoji; Itoh, Akio; Oyama, Ayu; Takahashi, Haruka

    2012-01-01

    We present a sensitive diffusion cloud chamber which does not require any radioactive sources. A major difference from commonly used chambers is the use of a heat sink as its bottom plate. The result of a performance test of the chamber is given. (Contains 8 figures.)

  9. Simplifying the Mathematical Treatment of Radioactive Decay

    ERIC Educational Resources Information Center

    Auty, Geoff

    2011-01-01

    Derivation of the law of radioactive decay is considered without prior knowledge of calculus or the exponential series. Calculus notation and exponential functions are used because ultimately they cannot be avoided, but they are introduced in a simple way and explained as needed. (Contains 10 figures, 1 box, and 1 table.)

  10. Canister arrangement for storing radioactive waste

    DOEpatents

    Lorenzo, D.K.; Van Cleve, J.E. Jr.

    1980-04-23

    The subject invention relates to a canister arrangement for jointly storing high level radioactive chemical waste and metallic waste resulting from the reprocessing of nuclear reactor fuel elements. A cylindrical steel canister is provided with an elongated centrally disposed billet of the metallic waste and the chemical waste in vitreous form is disposed in the annulus surrounding the billet.

  11. Annual Radioactive Waste Tank Inspection Program - 1997

    SciTech Connect

    McNatt, F.G.

    1998-05-01

    Aqueous radioactive wastes from Savannah River Site (SRS) separations processes are contained in large underground carbon steel tanks. Inspections made during 1997 to evaluate these vessels, and evaluations based on data accrued by inspections performed since the tanks were constructed are the subject of this report.

  12. Annual radioactive waste tank inspection program - 1999

    SciTech Connect

    Moore, C.J.

    2000-04-14

    Aqueous radioactive wastes from Savannah River Site (SRS) separations processes are contained in large underground carbon steel tanks. Inspections made during 1999 to evaluate these vessels and auxiliary appurtenances along with evaluations based on data accrued by inspections performed since the tanks were constructed are the subject of this report.

  13. Annual radioactive waste tank inspection program - 1996

    SciTech Connect

    McNatt, F.G.

    1997-04-01

    Aqueous radioactive wastes from Savannah River Site (SRS) separations processes are contained in large underground carbon steel tanks. Inspections made during 1996 to evaluate these vessels, and evaluations based on data accrued by inspections performed since the tanks were constructed, are the subject of this report.

  14. Hazardous chemical and radioactive wastes at Hanford

    SciTech Connect

    Keller, J.F.; Stewart, T.L.

    1991-07-01

    The Hanford Site was established in 1944 to produce plutonium for defense. During the past four decades, a number of reactors, processing facilities, and waste management facilities have been built at Hanford for plutonium production. Generally, Hanford`s 100 Area was dedicated to reactor operation; the 200 Area to fuel reprocessing, plutonium recovery, and waste management; and the 300 Area to fuel fabrication and research and development. Wastes generated from these operations included highly radioactive liquid wastes, which were discharged to single- and double-shell tanks; solid wastes, including both transuranic (TRU) and low-level wastes, which were buried or discharged to caissons; and waste water containing low- to intermediate-level radioactivity, which was discharged to the soil column via near-surface liquid disposal units such as cribs, ponds, and retention basins. Virtually all of the wastes contained hazardous chemical as well as radioactive constituents. This paper will focus on the hazardous chemical components of the radioactive mixed waste generated by plutonium production at Hanford. The processes, chemicals used, methods of disposition, fate in the environment, and actions being taken to clean up this legacy are described by location.

  15. Hazardous chemical and radioactive wastes at Hanford

    SciTech Connect

    Keller, J.F.; Stewart, T.L.

    1991-07-01

    The Hanford Site was established in 1944 to produce plutonium for defense. During the past four decades, a number of reactors, processing facilities, and waste management facilities have been built at Hanford for plutonium production. Generally, Hanford's 100 Area was dedicated to reactor operation; the 200 Area to fuel reprocessing, plutonium recovery, and waste management; and the 300 Area to fuel fabrication and research and development. Wastes generated from these operations included highly radioactive liquid wastes, which were discharged to single- and double-shell tanks; solid wastes, including both transuranic (TRU) and low-level wastes, which were buried or discharged to caissons; and waste water containing low- to intermediate-level radioactivity, which was discharged to the soil column via near-surface liquid disposal units such as cribs, ponds, and retention basins. Virtually all of the wastes contained hazardous chemical as well as radioactive constituents. This paper will focus on the hazardous chemical components of the radioactive mixed waste generated by plutonium production at Hanford. The processes, chemicals used, methods of disposition, fate in the environment, and actions being taken to clean up this legacy are described by location.

  16. Annual radioactive waste tank inspection program: 1995

    SciTech Connect

    McNatt, F.G. Sr.

    1996-04-01

    Aqueous radioactive wastes from Savannah River Site (SRS) separations processes are contained in large underground carbon steel tanks. Inspections made during 1995 to evaluate these vessels and evaluations based on data accrued by inspections performed since the tanks were constructed are the subject of this report

  17. Radioactive air emissions 1992 summary. Progress report

    SciTech Connect

    Wahl, L.

    1993-10-01

    This report summarizes, by radionuclide or product and by emitting facility, the Laboratory`s 1992 radioactive air emissions. In 1992, the total activity of radionuclides emitted into the air from Laboratory stacks was approximately 73,500 Ci. This was an increase over the activity of the total 1991 radioactive air emissions, which was approximately 62,400 Ci. Total 1992 Laboratory emissions of each radionuclide or product are summarized by tables and graphs in the first section of this report. Compared to 1991 radioactive air emissions, total tritium activity was decreased, total plutonium activity was decreased, total uranium activity was decreased, total mixed fission product activity was increased, total {sup 41}Ar activity was decreased, total gaseous/mixed activation product (except {sup 41}Ar) activity was increased, total particulate/vapor activation product activity was increased, and total {sup 32}P activity was decreased. Radioactive emissions from specific facilities are detailed in this report. Each section provides 1992 data on a single radionuclide or product and is further divided by emitting facility. For each facility from which a particular radionuclide or product was emitted, a bar chart displays the air emissions of each radionuclide or product from each facility over the 12 reporting periods of 1992, a line chart shows the trend in total emissions of that radionuclide or product from that facility for the past three years, the greatest activity during the 1990--1992 period is discussed, and unexpected or unusual results are noted.

  18. CHAINS. Analysis of Radioactive Decay Chains

    SciTech Connect

    Yuelys-Miksis, C.

    1988-05-01

    CHAINS computes the atom density of members of a single radioactive decay chain. The linearity of the Bateman equations allows tracing of interconnecting chains by manually accumulating results from separate calculations of single chains. Re-entrant loops can be treated as extensions of a single chain. Losses from the chain are also tallied.

  19. RADIOACTIVE MATERIALS IN BIOSOLIDS: DOSE MODELING

    EPA Science Inventory

    The Interagency Steering Committee on Radiation Standards (ISCORS) has recently completed a study of the occurrence within the United States of radioactive materials in sewage sludge and sewage incineration ash. One component of that effort was an examination of the possible tra...

  20. METHOD OF REMOVING RADIOACTIVE IODINE FROM GASES

    DOEpatents

    Silverman, L.

    1962-01-23

    A method of removing radioactive iodine from a gaseous medium is given in which the gaseous medium is adjusted to a temperature not exceeding 400 deg C and then passed over a copper fibrous pad having a coating of cupric sulfide deposited thereon. An ionic exchange on the pad results in the formation of cupric iodide and the release of sulfur. (AEC)

  1. ANNUAL RADIOACTIVE WASTE TANK INSPECTION PROGRAM 2008

    SciTech Connect

    West, B.; Waltz, R.

    2009-06-11

    Aqueous radioactive wastes from Savannah River Site (SRS) separations and vitrification processes are contained in large underground carbon steel tanks. Inspections made during 2008 to evaluate these vessels and other waste handling facilities along with evaluations based on data from previous inspections are the subject of this report.

  2. Obtaining and Investigating Unconventional Sources of Radioactivity

    ERIC Educational Resources Information Center

    Lapp, David R.

    2010-01-01

    This paper provides examples of naturally radioactive items that are likely to be found in most communities. Additionally, there is information provided on how to acquire many of these items inexpensively. I have found that the presence of these materials in the classroom is not only useful for teaching about nuclear radiation and debunking the…

  3. Method for decontamination of radioactive metal surfaces

    DOEpatents

    Bray, Lane A. (Richland, WA)

    1996-01-01

    Disclosed is a method for removing radioactive contaminants from metal surfaces by applying steam containing an inorganic acid and cerium IV. Cerium IV is applied to contaminated metal surfaces by introducing cerium IV in solution into a steam spray directed at contaminated metal surfaces. Cerium IV solution is converted to an essentially atomized or vapor phase by the steam.

  4. [Loss and uncontrolled use of radioactive sources].

    PubMed

    Govaerts, P

    2005-01-01

    In the course of history, exposure to radioactive sources escaping regular control, has been the main cause of fatal accidents, with the exception of the reactor accident at Chernobyl. After the disintegration of the Soviet Union, numerous lost sources have been found, sometimes with serious physical damage. The attacks of September 11, 2001 have focussed the attention on the possibility of nuclear terrorism. Although the risks of fatal consequences are rather limited, the possible uncontrolled exposure to ionizing radiation has an important psycho-social impact on the population. After a brief survey of the types of radioactive sources for medical and industrial applications and a discussion of the risks and exposure routes, possible scenarios are illustrated by well documented case histories. The main conclusions of this analysis are: Radioactive materials are not unique as a potential threat by toxic materials. The most serious consequences for individuals occur as the result of external radiation, mostly with skin contact with medium-active sources which are relatively easily accessible. The collective impact is mostly psycho-social and is more important for a dispersed contamination of the environment. Many sources are detected via medical complaints. The knowledge of the specific symptoms is consequently very important. A dispersion of radioactive contamination has usually considerable economic consequences. Accidents occur particularly, but certainly not exclusively, in relatively unstable countries. Change of owner or final evacuation of the source constitute a critical phase in many scenarios. PMID:16408827

  5. Annual radioactive waste tank inspection program - 1992

    SciTech Connect

    McNatt, F.G.

    1992-12-31

    Aqueous radioactive wastes from Savannah River Site (SRS) separations processes are contained in large underground carbon steel tanks. Inspections made during 1992 to evaluate these vessels and evaluations based on data accrued by inspections made since the tanks were constructed are the subject of this report.

  6. Recycling and Reuse of Radioactive Materials

    ERIC Educational Resources Information Center

    O'Dou, Thomas Joseph

    2012-01-01

    The Radiochemistry Program at the University of Nevada, Las Vegas (UNLV) has a Radiation Protection Program that was designed to provide students with the ability to safely work with radioactive materials in quantities that are not available in other academic environments. Requirements for continuous training and supervision make this unique

  7. Remediation of groundwater contaminated with radioactive compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Both naturally radioactive isotopes and isotopes from man-made sources may appear in groundwater. Depending on the physical and chemical characteristics of the contaminant, different types of treatment methods must be applied to reduce the concentration. The following chapter discusses treatment opt...

  8. Ion beam analysis of radioactive samples

    NASA Astrophysics Data System (ADS)

    Raepsaet, C.; Khodja, H.; Bossis, P.; Pipon, Y.; Roudil, D.

    2009-06-01

    The nuclear microprobe facility of the Pierre Se Laboratory is fitted with two microbeam lines. One is dedicated to non-active samples. The other one, located in a controlled shielded area, offers the unique feature of being devoted to radioactive samples. Operational since 1998, it is strongly linked to nuclear research programs and has been dimensioned to accept radioactive but non-contaminant radioactive samples, including small quantities of UOX or MOX irradiated fuel. The samples, transported in a shipping cask, are unloaded and handled in hot cells with slaved arms. The analysis chamber, situated in a concrete cell, is equipped with charged particle detectors and a Si(Li) X-ray detector, shielded in order to reduce the radioactive noise produced by the sample, allowing ERDA, RBS, NRA and PIXE. After a description of the facility, including the sample handling in the hot cells and the analysis chamber, we will give an overview of the various experimental programs which have been performed, with an emphasis on the determination of the hydrogen distribution and local content in nuclear fuel cladding tubes.

  9. Proceedings of the first international conference on radioactive nuclear beams

    SciTech Connect

    Myers, W.D.; Nitschke, J.M.; Norman, E.B. )

    1990-01-01

    This report contains the paper submitted to the radioactive nuclear beams conference. The areas these papers encompass are: Radioactive Nuclear Beam (RNB) facilities and RNB production, astrophysics, nuclear structure, macroscopic properties of nuclei, and RNB applications.

  10. Radioactive Waste Management in Central Asia - 12034

    SciTech Connect

    Zhunussova, Tamara; Sneve, Malgorzata; Liland, Astrid

    2012-07-01

    After the collapse of the Soviet Union the newly independent states in Central Asia (CA) whose regulatory bodies were set up recently are facing problems with the proper management of radioactive waste and so called 'nuclear legacy' inherited from the past activities. During the former Soviet Union (SU) period, various aspects of nuclear energy use took place in CA republics of Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan. Activities range from peaceful use of energy to nuclear testing for example at the former Semipalatinsk Nuclear Test Site (SNTS) in Kazakhstan, and uranium mining and milling industries in all four countries. Large amounts of radioactive waste (RW) have been accumulated in Central Asia and are waiting for its safe disposal. In 2008 the Norwegian Radiation Protection Authority (NRPA), with the support of the Norwegian Ministry of Foreign Affairs, has developed bilateral projects that aim to assist the regulatory bodies in Kazakhstan, Kyrgyzstan Tajikistan, and Uzbekistan (from 2010) to identify and draft relevant regulatory requirements to ensure the protection of the personnel, population and environment during the planning and execution of remedial actions for past practices and radioactive waste management in the CA countries. The participating regulatory authorities included: Kazakhstan Atomic Energy Agency, Kyrgyzstan State Agency on Environmental Protection and Forestry, Nuclear Safety Agency of Tajikistan, and State Inspectorate on Safety in Industry and Mining of Uzbekistan. The scope of the projects is to ensure that activities related to radioactive waste management in both planned and existing exposure situations in CA will be carried out in accordance with the international guidance and recommendations, taking into account the relevant regulatory practice from other countries in this area. In order to understand the problems in the field of radioactive waste management we have analysed the existing regulations through the so called 'Threat assessment' in each CA country which revealed additional problems in the existing regulatory documents beyond those described at the start of our ongoing bilateral projects in Kazakhstan, Kirgizistan Tajikistan and Uzbekistan. (authors)

  11. 49 CFR 177.842 - Class 7 (radioactive) material.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Class 7 (radioactive) material. 177.842 Section... HIGHWAY Loading and Unloading 177.842 Class 7 (radioactive) material. (a) The number of packages of Class 7 (radioactive) materials in any transport vehicle or in any single group in any storage...

  12. 49 CFR 177.842 - Class 7 (radioactive) material.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Class 7 (radioactive) material. 177.842 Section... HIGHWAY Loading and Unloading 177.842 Class 7 (radioactive) material. (a) The number of packages of Class 7 (radioactive) materials in any transport vehicle or in any single group in any storage...

  13. 10 CFR 76.83 - Transfer of radioactive material.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 2 2011-01-01 2011-01-01 false Transfer of radioactive material. 76.83 Section 76.83 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.83 Transfer of radioactive material. (a) The Corporation may not transfer radioactive material except...

  14. 10 CFR 76.83 - Transfer of radioactive material.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Transfer of radioactive material. 76.83 Section 76.83 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.83 Transfer of radioactive material. (a) The Corporation may not transfer radioactive material except...

  15. 49 CFR 177.842 - Class 7 (radioactive) material.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Class 7 (radioactive) material. 177.842 Section... HIGHWAY Loading and Unloading § 177.842 Class 7 (radioactive) material. (a) The number of packages of Class 7 (radioactive) materials in any transport vehicle or in any single group in any storage...

  16. 49 CFR 172.310 - Class 7 (radioactive) materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Class 7 (radioactive) materials. 172.310 Section... REQUIREMENTS, AND SECURITY PLANS Marking § 172.310 Class 7 (radioactive) materials. In addition to any other markings required by this subpart, each package containing Class 7 (radioactive) materials must be...

  17. Review of physics, instrumentation and dosimetry of radioactive isotopes

    NASA Technical Reports Server (NTRS)

    Sinclair, W. K.

    1967-01-01

    General radioactive isotope information, stressing radioactivity, methods of measurement, and dosimetry of radioactive nuclides have been reviewed to serve as a reference for the medical profession. Instability of radionuclides, principal types of emission, and measurement of ionizing radiation are among the topics discussed.

  18. 46 CFR 109.559 - Explosives and radioactive materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Explosives and radioactive materials. 109.559 Section... UNITS OPERATIONS Miscellaneous § 109.559 Explosives and radioactive materials. Except as authorized by the master or person in charge, no person may use explosives or radioactive materials and equipment...

  19. 46 CFR 109.559 - Explosives and radioactive materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Explosives and radioactive materials. 109.559 Section... UNITS OPERATIONS Miscellaneous § 109.559 Explosives and radioactive materials. Except as authorized by the master or person in charge, no person may use explosives or radioactive materials and equipment...

  20. 46 CFR 109.559 - Explosives and radioactive materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Explosives and radioactive materials. 109.559 Section... UNITS OPERATIONS Miscellaneous § 109.559 Explosives and radioactive materials. Except as authorized by the master or person in charge, no person may use explosives or radioactive materials and equipment...

  1. 46 CFR 109.559 - Explosives and radioactive materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Explosives and radioactive materials. 109.559 Section... UNITS OPERATIONS Miscellaneous § 109.559 Explosives and radioactive materials. Except as authorized by the master or person in charge, no person may use explosives or radioactive materials and equipment...

  2. 46 CFR 109.559 - Explosives and radioactive materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Explosives and radioactive materials. 109.559 Section... UNITS OPERATIONS Miscellaneous § 109.559 Explosives and radioactive materials. Except as authorized by the master or person in charge, no person may use explosives or radioactive materials and equipment...

  3. 10 CFR 76.83 - Transfer of radioactive material.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false Transfer of radioactive material. 76.83 Section 76.83 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety 76.83 Transfer of radioactive material. (a) The Corporation may not transfer radioactive material except...

  4. 10 CFR 76.83 - Transfer of radioactive material.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 2 2013-01-01 2013-01-01 false Transfer of radioactive material. 76.83 Section 76.83 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety 76.83 Transfer of radioactive material. (a) The Corporation may not transfer radioactive material except...

  5. 10 CFR 76.83 - Transfer of radioactive material.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 2 2012-01-01 2012-01-01 false Transfer of radioactive material. 76.83 Section 76.83 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety 76.83 Transfer of radioactive material. (a) The Corporation may not transfer radioactive material except...

  6. 48 CFR 245.7310-6 - Radioactive material.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Radioactive material. 245... Radioactive material. The following shall be used whenever the property offered for sale is capable of emitting ionized radiation: Radioactive Material Purchasers are warned that the property may be capable...

  7. 10 CFR 835.603 - Radiological areas and radioactive material areas.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... radioactivity area. The words “Caution, Airborne Radioactivity Area” or “Danger, Airborne Radioactivity Area” shall be posted at each airborne radioactivity area. (e) Contamination area. The words...

  8. 10 CFR 835.603 - Radiological areas and radioactive material areas.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... radioactivity area. The words “Caution, Airborne Radioactivity Area” or “Danger, Airborne Radioactivity Area” shall be posted at each airborne radioactivity area. (e) Contamination area. The words...

  9. 10 CFR 835.603 - Radiological areas and radioactive material areas.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... radioactivity area. The words “Caution, Airborne Radioactivity Area” or “Danger, Airborne Radioactivity Area” shall be posted at each airborne radioactivity area. (e) Contamination area. The words...

  10. 10 CFR 835.603 - Radiological areas and radioactive material areas.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... radioactivity area. The words “Caution, Airborne Radioactivity Area” or “Danger, Airborne Radioactivity Area” shall be posted at each airborne radioactivity area. (e) Contamination area. The words...

  11. 10 CFR 835.603 - Radiological areas and radioactive material areas.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... radioactivity area. The words “Caution, Airborne Radioactivity Area” or “Danger, Airborne Radioactivity Area” shall be posted at each airborne radioactivity area. (e) Contamination area. The words...

  12. Mobility of Po and U-isotopes under acid mine drainage conditions: an experimental approach with samples from Río Tinto area (SW Spain).

    PubMed

    Barbero, L; Gázquez, M J; Bolívar, J P; Casas-Ruiz, M; Hierro, A; Baskaran, M; Ketterer, M E

    2014-12-01

    Under acid mine drainage (AMD) conditions, the solubilities and mobilities of many elements are vastly different from conditions prevailing in most natural waters. Studies are underway in the Río Tinto area (Iberian Pyrite Belt), in order to understand the behavior and mobility of long-lived U-series radionuclides under AMD conditions. A set of leaching experiments utilizing typical country rocks from the Tinto River basin, waste rock pile composite materials, iron-rich riverbed sediments and gossan (weathered naturally rock) were performed towards this purpose. Initial leaching experiments using distilled water kept in contact with solid material for 300, 100, 50 and 1 h resulted in very low concentrations of U with (234)U/(238)U activity ratios close to equilibrium and activity concentrations of (210)Po < 0.03 mBq/g. Leaching experiments performed with sulfuric acid media (0.1 and 0.01 M), and contact times between the solid and solution for 24 h were conducted to quantify the amount of U-isotopes and (210)Po leached, and the radioactive disequilibria generated between the radionuclides in the leachate. These experiments show that Po mobility in acidic conditions (pH around 1-2) is very low, with (210)Po activity in the leachate to be 6% in average for the solid sample. By contrast, mobility of U-isotopes is higher than that of Po, around 1.2%. PMID:24308958

  13. Radioactive hot cell access hole decontamination machine

    DOEpatents

    Simpson, William E.

    1982-01-01

    Radioactive hot cell access hole decontamination machine. A mobile housing has an opening large enough to encircle the access hole and has a shielding door, with a door opening and closing mechanism, for uncovering and covering the opening. The housing contains a shaft which has an apparatus for rotating the shaft and a device for independently translating the shaft from the housing through the opening and access hole into the hot cell chamber. A properly sized cylindrical pig containing wire brushes and cloth or other disks, with an arrangement for releasably attaching it to the end of the shaft, circumferentially cleans the access hole wall of radioactive contamination and thereafter detaches from the shaft to fall into the hot cell chamber.

  14. Comparative alkali washing of simulated radioactive sludge

    SciTech Connect

    Fugate, G.A.; Ensor, D.D.; Egan, B.Z.

    1996-10-01

    The treatment of large volumes of radioactive sludge generated from uranium and plutonium recovery processes is a pressing problem in the environmental restoration currently planned at various U.S. Department of Energy sites. This sludge, commonly stored in underground tanks, is mainly in the form of metal oxides or precipitated metal hydroxides and the bulk of this material is nonradioactive. One method being developed to pretreat this waste takes advantage of the amphoteric character of aluminum and other nonradioactive elements. Previous studies have reported on the dissolution of eleven elements from simulated sludge using NaOH solutions up to 6M. This work provides a comparative study using KOH. The effectiveness of the alkali washing as a treatment method to reduce the bulk of radioactive sludge requiring long term isolation will be discussed.

  15. Radiation hormesis: Radioactive waste for health

    SciTech Connect

    Luckey, T.D.

    1995-12-31

    Hormesis is the stimulation of any system by low doses of any agent. The hormesis model is particularly applicable to radioactive waste management. Radiation hormesis encompasses the beneficial effects of low-dose irradiation in both animals and humans. The radiation hormesis model comprises statistically significant (X{sup 2} test) results that compare total death rates and cancer death rates in exposed and unexposed nuclear workers. The usual {open_quotes}healthy worker effect{close_quotes} is negated because both groups were in the same plants. These data invalidate all linear (no-threshold) models. This dramatic change in concepts about the effects of low-dose irradiation transforms problems about radioactive waste into solutions for improved health.

  16. Airborne radioactivity surveys for phosphate in Florida

    USGS Publications Warehouse

    Moxham, Robert M.

    1953-01-01

    Airborne radioactivity surveys totalling 5,600 traverse miles were made in ten areas in Florida, which were thought to be geologically favorable for the occurrence of uraniferous phosphate deposits. Abnormal radioactivity was recorded in eight of the ten areas surveyed. The anomalies are located in Bradford, Clay, Columbia, DeSoto, Dixie, Lake, Marion, Orange, Sumter, Taylor, and Union Counties. Two of the anomalies were investigated briefly on the ground. One resulted from a deposit of river-pebble phosphate in the Peace River valley; samples of the river pebble contain an average of 0.013 percent equivalent uranium. The other anomaly resulted from outcrops of leached phosphate rock containing as much as 0.016 percent equivalent uranium. Several anomalies in other areas were recorded at or near localities where phosphate deposits have been reported to occur.

  17. Radioactive scrap metal decontamination technology assessment report

    SciTech Connect

    Buckentin, J.M.; Damkroger, B.K.; Schlienger, M.E.

    1996-04-01

    Within the DOE complex there exists a tremendous quantity of radioactive scrap metal. As an example, it is estimated that within the gaseous diffusion plants there exists in excess of 700,000 tons of contaminated stainless steel. At present, valuable material is being disposed of when it could be converted into a high quality product. Liquid metal processing represents a true recycling opportunity for this material. By applying the primary production processes towards the material`s decontamination and re-use, the value of the strategic resource is maintained while drastically reducing the volume of material in need of burial. Potential processes for the liquid metal decontamination of radioactively contaminated metal are discussed and contrasted. Opportunities and technology development issues are identified and discussed. The processes compared are: surface decontamination; size reduction, packaging and burial; melting technologies; electric arc melting; plasma arc centrifugal treatment; air induction melting; vacuum induction melting; and vacuum induction melting and electroslag remelting.

  18. Method of handling radioactive alkali metal waste

    DOEpatents

    Wolson, Raymond D. (Lockport, IL); McPheeters, Charles C. (Plainfield, IL)

    1980-01-01

    Radioactive alkali metal is mixed with particulate silica in a rotary drum reactor in which the alkali metal is converted to the monoxide during rotation of the reactor to produce particulate silica coated with the alkali metal monoxide suitable as a feed material to make a glass for storing radioactive material. Silica particles, the majority of which pass through a 95 mesh screen or preferably through a 200 mesh screen, are employed in this process, and the preferred weight ratio of silica to alkali metal is 7 to 1 in order to produce a feed material for the final glass product having a silica to alkali metal monoxide ratio of about 5 to 1.

  19. Two-proton radioactivity of 45Fe

    SciTech Connect

    Miernik, K.; Dominik, W.; Janas, Z.; Pfutzner, M.; Grigorenko, L.; Bingham, C. R.; Czyrkowski, H.; Cwiok, Mikolaj; Darby, Iain; Dabrowski, Ryszard; Ginter, T. N.; Grzywacz, R.; Karny, M.; Korgul, A.; Kusmierz, W.; Liddick, Sean; Rajabali, Mustafa; Rykaczewski, Krzysztof Piotr; Stolz, A.

    2009-01-01

    In an experiment at the SISSI-LISE3 facility of GANIL, the decay of the proton drip line nucleus 45Fe has been studied. Fragment-implantation events have been correlated with radioactive decay events in a 16x16 pixel silicon-strip detector. The decay-energy spectrum of 45Fe implants shows a distinct peak at (1.14+/-0.04) MeV with a half-life of T(1/2)=(4.7(+3.4)(-1.4)) ms. None of the events in this peak is in coincidence with beta particles. For a longer correlation interval, daughter decays of the two-proton daughter 43Cr can be observed after 45Fe implantation. The decay energy for 45Fe agrees nicely with several theoretical predictions for two-proton radioactivity.

  20. Airborne radioactivity surveys for phosphate in Florida

    USGS Publications Warehouse

    Moxham, Robert M.

    1954-01-01

    Airborne radioactivity surveys totaling 5, 600 traverse miles were made in 10 areas in Florida, which were thought to be geologically favorable for deposits of uraniferous phosphate. Abnormal radioactivity was recorded in 8 of the 10 areas surveyed. The anomalies are located in Bradford, Clay, Columbia, DeSoto, Dixie, Lake, Marion, Orange, Sumter, Taylor, and Union Counties. Two of the anomalies were investigated briefly on the ground. One resulted from a deposit of river-pebble phosphate in the Peace River valley; the river-pebble samples contain an average of 0.013 percent equivalent uranium. The other anomaly resulted from outcrops of leached phosphatic rock containing as much as 0. 016 percent equivalent uranium. Several anomalies in other areas were recorded at or near localities where phosphate deposits have been reported.

  1. Nuclear astrophysics with radioactive ions at FAIR

    NASA Astrophysics Data System (ADS)

    Reifarth, R.; Altstadt, S.; Göbel, K.; Heftrich, T.; Heil, M.; Koloczek, A.; Langer, C.; Plag, R.; Pohl, M.; Sonnabend, K.; Weigand, M.; Adachi, T.; Aksouh, F.; Al-Khalili, J.; AlGarawi, M.; AlGhamdi, S.; Alkhazov, G.; Alkhomashi, N.; Alvarez-Pol, H.; Alvarez-Rodriguez, R.; Andreev, V.; Andrei, B.; Atar, L.; Aumann, T.; Avdeichikov, V.; Bacri, C.; Bagchi, S.; Barbieri, C.; Beceiro, S.; Beck, C.; Beinrucker, C.; Belier, G.; Bemmerer, D.; Bendel, M.; Benlliure, J.; Benzoni, G.; Berjillos, R.; Bertini, D.; Bertulani, C.; Bishop, S.; Blasi, N.; Bloch, T.; Blumenfeld, Y.; Bonaccorso, A.; Boretzky, K.; Botvina, A.; Boudard, A.; Boutachkov, P.; Boztosun, I.; Bracco, A.; Brambilla, S.; Briz Monago, J.; Caamano, M.; Caesar, C.; Camera, F.; Casarejos, E.; Catford, W.; Cederkall, J.; Cederwall, B.; Chartier, M.; Chatillon, A.; Cherciu, M.; Chulkov, L.; Coleman-Smith, P.; Cortina-Gil, D.; Crespi, F.; Crespo, R.; Cresswell, J.; Csatlós, M.; Déchery, F.; Davids, B.; Davinson, T.; Derya, V.; Detistov, P.; Diaz Fernandez, P.; DiJulio, D.; Dmitry, S.; Doré, D.; Dueñas, J.; Dupont, E.; Egelhof, P.; Egorova, I.; Elekes, Z.; Enders, J.; Endres, J.; Ershov, S.; Ershova, O.; Fernandez-Dominguez, B.; Fetisov, A.; Fiori, E.; Fomichev, A.; Fonseca, M.; Fraile, L.; Freer, M.; Friese, J.; Borge, M. G.; Galaviz Redondo, D.; Gannon, S.; Garg, U.; Gasparic, I.; Gasques, L.; Gastineau, B.; Geissel, H.; Gernhäuser, R.; Ghosh, T.; Gilbert, M.; Glorius, J.; Golubev, P.; Gorshkov, A.; Gourishetty, A.; Grigorenko, L.; Gulyas, J.; Haiduc, M.; Hammache, F.; Harakeh, M.; Hass, M.; Heine, M.; Hennig, A.; Henriques, A.; Herzberg, R.; Holl, M.; Ignatov, A.; Ignatyuk, A.; Ilieva, S.; Ivanov, M.; Iwasa, N.; Jakobsson, B.; Johansson, H.; Jonson, B.; Joshi, P.; Junghans, A.; Jurado, B.; Körner, G.; Kalantar, N.; Kanungo, R.; Kelic-Heil, A.; Kezzar, K.; Khan, E.; Khanzadeev, A.; Kiselev, O.; Kogimtzis, M.; Körper, D.; Kräckmann, S.; Kröll, T.; Krücken, R.; Krasznahorkay, A.; Kratz, J.; Kresan, D.; Krings, T.; Krumbholz, A.; Krupko, S.; Kulessa, R.; Kumar, S.; Kurz, N.; Kuzmin, E.; Labiche, M.; Langanke, K.; Lazarus, I.; Le Bleis, T.; Lederer, C.; Lemasson, A.; Lemmon, R.; Liberati, V.; Litvinov, Y.; Löher, B.; Lopez Herraiz, J.; Münzenberg, G.; Machado, J.; Maev, E.; Mahata, K.; Mancusi, D.; Marganiec, J.; Martinez Perez, M.; Marusov, V.; Mengoni, D.; Million, B.; Morcelle, V.; Moreno, O.; Movsesyan, A.; Nacher, E.; Najafi, M.; Nakamura, T.; Naqvi, F.; Nikolski, E.; Nilsson, T.; Nociforo, C.; Nolan, P.; Novatsky, B.; Nyman, G.; Ornelas, A.; Palit, R.; Pandit, S.; Panin, V.; Paradela, C.; Parkar, V.; Paschalis, S.; Pawłowski, P.; Perea, A.; Pereira, J.; Petrache, C.; Petri, M.; Pickstone, S.; Pietralla, N.; Pietri, S.; Pivovarov, Y.; Potlog, P.; Prokofiev, A.; Rastrepina, G.; Rauscher, T.; Ribeiro, G.; Ricciardi, M.; Richter, A.; Rigollet, C.; Riisager, K.; Rios, A.; Ritter, C.; Rodriguez Frutos, T.; Rodriguez Vignote, J.; Röder, M.; Romig, C.; Rossi, D.; Roussel-Chomaz, P.; Rout, P.; Roy, S.; Söderström, P.; Saha Sarkar, M.; Sakuta, S.; Salsac, M.; Sampson, J.; Sanchez, J.; Rio Saez, del; Sanchez Rosado, J.; Sanjari, S.; Sarriguren, P.; Sauerwein, A.; Savran, D.; Scheidenberger, C.; Scheit, H.; Schmidt, S.; Schmitt, C.; Schnorrenberger, L.; Schrock, P.; Schwengner, R.; Seddon, D.; Sherrill, B.; Shrivastava, A.; Sidorchuk, S.; Silva, J.; Simon, H.; Simpson, E.; Singh, P.; Slobodan, D.; Sohler, D.; Spieker, M.; Stach, D.; Stan, E.; Stanoiu, M.; Stepantsov, S.; Stevenson, P.; Strieder, F.; Stuhl, L.; Suda, T.; Sümmerer, K.; Streicher, B.; Taieb, J.; Takechi, M.; Tanihata, I.; Taylor, J.; Tengblad, O.; Ter-Akopian, G.; Terashima, S.; Teubig, P.; Thies, R.; Thoennessen, M.; Thomas, T.; Thornhill, J.; Thungstrom, G.; Timar, J.; Togano, Y.; Tomohiro, U.; Tornyi, T.; Tostevin, J.; Townsley, C.; Trautmann, W.; Trivedi, T.; Typel, S.; Uberseder, E.; Udias, J.; Uesaka, T.; Uvarov, L.; Vajta, Z.; Velho, P.; Vikhrov, V.; Volknandt, M.; Volkov, V.; von Neumann-Cosel, P.; von Schmid, M.; Wagner, A.; Wamers, F.; Weick, H.; Wells, D.; Westerberg, L.; Wieland, O.; Wiescher, M.; Wimmer, C.; Wimmer, K.; Winfield, J. S.; Winkel, M.; Woods, P.; Wyss, R.; Yakorev, D.; Yavor, M.; Zamora Cardona, J.; Zartova, I.; Zerguerras, T.; Zgura, M.; Zhdanov, A.; Zhukov, M.; Zieblinski, M.; Zilges, A.; Zuber, K.

    2016-01-01

    The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process, β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes.

  2. Radioactive targets for nuclear accelerator experiments

    NASA Astrophysics Data System (ADS)

    Maier, H. J.; Grossmann, R.; Friebel, H. U.

    1991-05-01

    The quality of a nuclear accelerator target is assessed in terms of its purity, mechanical strength, thickness uniformity and microstructure. High vacuum thin film condensation is the preferred production method, because it results in microscopically smooth targets of high purity. Special variants of this technique are used in our hot laboratory to prepare radioactive targets of good macroscopic and microscopic homogeneity while keeping the consumption of isotopic material on a low level. A particular type of carbon backing provides excellent mechanical strength to the targets. New equipment including modern production plants as well as glove boxes and hot cell facilities permits to maintain the service for a long period. In nuclear physics experiments with radioactive targets problems may arise from a possible contamination of the beam line or other equipment. A few protective measures to overcome these difficulties are mentioned.

  3. Solar Powered Radioactive Air Monitoring Stations

    SciTech Connect

    Barnett, J. M.; Bisping, Lynn E.; Gervais, Todd L.

    2013-10-30

    Environmental monitoring of ambient air for radioactive material is required as stipulated in the PNNL Site radioactive air license. Sampling ambient air at identified preferred locations could not be initially accomplished because utilities were not readily available. Therefore, solar powered environmental monitoring systems were considered as a possible option. PNNL purchased two 24-V DC solar powered environmental monitoring systems which consisted of solar panels, battery banks, and sampling units. During an approximate four month performance evaluation period, the solar stations operated satisfactorily at an on-site test location. They were subsequently relocated to their preferred locations in June 2012 where they continue to function adequately under the conditions found in Richland, Washington.

  4. Handbook of high-level radioactive waste transportation

    SciTech Connect

    Sattler, L.R.

    1992-10-01

    The High-Level Radioactive Waste Transportation Handbook serves as a reference to which state officials and members of the general public may turn for information on radioactive waste transportation and on the federal government`s system for transporting this waste under the Civilian Radioactive Waste Management Program. The Handbook condenses and updates information contained in the Midwestern High-Level Radioactive Waste Transportation Primer. It is intended primarily to assist legislators who, in the future, may be called upon to enact legislation pertaining to the transportation of radioactive waste through their jurisdictions. The Handbook is divided into two sections. The first section places the federal government`s program for transporting radioactive waste in context. It provides background information on nuclear waste production in the United States and traces the emergence of federal policy for disposing of radioactive waste. The second section covers the history of radioactive waste transportation; summarizes major pieces of legislation pertaining to the transportation of radioactive waste; and provides an overview of the radioactive waste transportation program developed by the US Department of Energy (DOE). To supplement this information, a summary of pertinent federal and state legislation and a glossary of terms are included as appendices, as is a list of publications produced by the Midwestern Office of The Council of State Governments (CSG-MW) as part of the Midwestern High-Level Radioactive Waste Transportation Project.

  5. Electrically Driven Technologies for Radioactive Aerosol Abatement

    SciTech Connect

    David W. DePaoli; Ofodike A. Ezekoye; Costas Tsouris; Valmor F. de Almeida

    2003-01-28

    The purpose of this research project was to develop an improved understanding of how electriexecy driven processes, including electrocoalescence, acoustic agglomeration, and electric filtration, may be employed to efficiently treat problems caused by the formation of aerosols during DOE waste treatment operations. The production of aerosols during treatment and retrieval operations in radioactive waste tanks and during thermal treatment operations such as calcination presents a significant problem of cost, worker exposure, potential for release, and increased waste volume.

  6. Radioactive-ion-beam research at Livermore

    NASA Astrophysics Data System (ADS)

    Haight, R. C.; Mathews, G. J.; Ward, R. A.; Woosley, S. E.

    1983-06-01

    The ability to produce secondary radioactive heavy ion beams which can be isolated, focused, and transported to a secondary target can enable reaction studies and other research with the approximately more than 1300 nuclei with decay lifetimes approximately more than 1 microsec. Current research in secondary beam production and future applications in astrophysics, nuclear structure, heavy ion physics, and radiotherapy are examined as well as associated spin off and technology transfer in applied physics.

  7. A Simple Example of Radioactive Dating

    ERIC Educational Resources Information Center

    Brown, Todd

    2014-01-01

    Although nuclear half-life is vital to physics and physical science, and to sensitive societal issues from nuclear waste to the age of the Earth, a true lab on half-life is almost never done at the college or high school level. Seldom are students able to use radioactivity to actually date when an object came into being, as is done in this

  8. A New Interpretation of Cluster Radioactivity Mechanism

    NASA Astrophysics Data System (ADS)

    Cherepanov, E. A.; Volkov, V. V.

    2015-11-01

    The basis for cluster radioactivity is the property of nuclei of light isotopes of elements heavier than lead to spontaneously form clusters -- nuclei of light elements -- from valence nucleons, which gives rise to asymmetric nuclear molecules. The cluster formation proceeds through successive excitation-free transfer of valence nucleons to the ? particle and to subsequent light nuclei. Nuclear molecule formation is accompanied by a considerable amount of released energy, which allows quantum-mechanical penetration of the cluster through the exit Coulomb barrier.

  9. A Simple Example of Radioactive Dating

    ERIC Educational Resources Information Center

    Brown, Todd

    2014-01-01

    Although nuclear half-life is vital to physics and physical science, and to sensitive societal issues from nuclear waste to the age of the Earth, a true lab on half-life is almost never done at the college or high school level. Seldom are students able to use radioactivity to actually date when an object came into being, as is done in this…

  10. Radioactivity in the industrial effluent disposed soil

    NASA Astrophysics Data System (ADS)

    Senthilkumar, R. D.; Narayanaswamy, R.; Meenashisundaram, V.

    2012-04-01

    Studies on radiation and radioactivity distribution in the soils of effluent disposed from the sugar industry in India have been conducted. The external gamma dose rates in air and natural radionuclides activities in the soils were measured using an Environmental Radiation Dosimeter and a Gamma-ray Spectrometer respectively. The soil samples were also subject to various physico-chemical analyses. This study revealed some remarkable results that are discussed in the article.

  11. Phosphate Bonded Solidification of Radioactive Incinerator Wastes

    SciTech Connect

    Walker, B. W.

    1999-04-13

    The incinerator at the Department of Energy Savannah River Site burns low level radioactive and hazardous waste. Ash and scrubber system waste streams are generated during the incineration process. Phosphate Ceramic technology is being tested to verify the ash and scrubber waste streams can be stabilized using this solidification method. Acceptance criteria for the solid waste forms include leachability, bleed water, compression testing, and permeability. Other testing on the waste forms include x-ray diffraction and scanning electron microscopy.

  12. Fabrication of radioactive stents by ion implantation

    NASA Astrophysics Data System (ADS)

    Huttel, Erhard; Kaltenbaek, Johann; Schloesser, Klaus; Schweickert, Hermann

    2002-02-01

    Worldwide about one million patients require treatment of stenosed coronary arteries annually. Often a tubular stainless steel mesh (stent) is implanted to mechanically support the injured vessel. Restenosis, an abundant complication (20%-30%) can be prevented, if the vessel is treated with ionizing radiation. Stents can deliver radiation if they are made radioactive. The radio isotope 32P is well suited when ion implanted. Radioactive ions sources require high efficiency to keep the radioactive inventory small. Reliability, ease of operation, and maintenance are mandatory. A small emittance is important to minimize losses during mass separation and beam transport. A 2.45 GHz ECR source was developed for the implantation of 32P. The source consists of two coils for the axial and a permanent hexapole for the radial confinement. The microwaves are fed in radially by a loop connected to a silver plated brass tube surrounding the plasma chamber. The plasma chamber is made from Pyrex. Neutron activated phosphorus, containing 30 ppm 32P, is introduced from the rear end on a rod. As support gas D2 is used. By this 32P+ can be separated from (31PD)+. The extraction is done in two steps: 60 kV-30 kV-ground. Mass separation is accomplished by a double focusing 90° magnet (radius 500 mm). During four years of operation about 1000 radioactive stents per year have been provided for animal experiments and clinical trials. Only one maintenance to exchange the extraction system due to degradation of high voltage stability was required so far.

  13. Radioactive materials released from nuclear power plants

    SciTech Connect

    Tichler, J.; Norden, K.; Congemi, J. )

    1989-10-01

    Releases of radioactive materials in airborne and liquid effluents from commercial light water reactors during 1987 have been compiled and reported. Data on solid waste shipments as well as selected operating information have been included. This report supplements earlier annual reports issued by the former Atomic Energy Commission and the Nuclear Regulatory Commission. The 1987 release data are summarized in tabular form. Data covering specific radionuclides are summarized. 16 tabs.

  14. Radioactive materials released from nuclear power plants

    SciTech Connect

    Tichler, J.; Norden, K.; Congemi, J. )

    1991-05-01

    Releases of radioactive materials in airborne and liquid effluents from commercial light water reactors during 1988 have been compiled and reported. Data on solid waste shipments as well as selected operating information have been included. This report supplements earlier annual reports issued by the former Atomic Energy Commission and the Nuclear Regulatory Commission. The 1988 release data are summarized in tabular form. Data covering specific radionuclides are summarized. 16 tabs.

  15. Radioactive Waste Burial Grounds. Environmental Information Document

    SciTech Connect

    Jaegge, W.J.; Kolb, N.L.; Looney, B.B.; Marine, I.W.; Towler, O.A.; Cook, J.R.

    1987-03-01

    This document provides environmental information on postulated closure options for the Radioactive Waste Burial Grounds at the Savannah River Plant and was developed as background technical documentation for the Department of Energy`s proposed Environmental Impact Statement (EIS) on waste management activities for groundwater protection at the plant. The results of groundwater and atmospheric pathway analyses, accident analysis, and other environmental assessments discussed in this document are based upon a conservative analysis of all foreseeable scenarios as defined by the National Environmental Policy Act (CFR, 1986). The scenarios do not necessarily represent actual environmental conditions. This document is not meant to be used as a closure plan or other regulatory document to comply with required federal or state environmental regulations. The closure options considered for the Radioactive Waste Burial Grounds are waste removal and closure, no waste removal and closure, and no action. The predominant pathways for human exposure to chemical and/or radioactive constituents are through surface, subsurface, and atmospheric transport. Modeling calculations were made to determine the risks to human population via these general pathways for the three postulated closure options. An ecological assessment was conducted to predict the environmental impacts on aquatic and terrestrial biota. The relative costs for each of the closure options were estimated.

  16. Future radioactive liquid waste streams study

    SciTech Connect

    Rey, A.S.

    1993-11-01

    This study provides design planning information for the Radioactive Liquid Waste Treatment Facility (RLWTF). Predictions of estimated quantities of Radioactive Liquid Waste (RLW) and radioactivity levels of RLW to be generated are provided. This information will help assure that the new treatment facility is designed with the capacity to treat generated RLW during the years of operation. The proposed startup date for the RLWTF is estimated to be between 2002 and 2005, and the life span of the facility is estimated to be 40 years. The policies and requirements driving the replacement of the current RLW treatment facility are reviewed. Historical and current status of RLW generation at Los Alamos National Laboratory are provided. Laboratory Managers were interviewed to obtain their insights into future RLW activities at Los Alamos that might affect the amount of RLW generated at the Lab. Interviews, trends, and investigation data are analyzed and used to create scenarios. These scenarios form the basis for the predictions of future RLW generation and the level of RLW treatment capacity which will be needed at LANL.

  17. Packaging and transportation of radioactively contaminated lead

    SciTech Connect

    Gleason, Eugene; Holden, Gerard

    2007-07-01

    Under the management of the Nuclear Decommissioning Authority (NDA) the government of the United Kingdom has launched an ambitious program to remediate the nation's nuclear waste legacy. Over a twenty-five year period NDA plans to decommission several first generation nuclear power plants and other radioactive facilities. The use innovative, safe 'fit for purpose' technologies will be a major part of this complex program. This paper will present a case study of a recently completed project undertaken in support of the nuclear decommissioning activities at the Sellafield site in the United Kingdom. The focus is on an innovative application of new packaging technology developed for the safe transportation of radioactively contaminated lead objects. Several companies collaborated on the project and contributed to its safe and successful conclusion. These companies include British Nuclear Group, Gravatom Engineering, W. F. Bowker Transport, Atlantic Container Lines, MHF Logistical Solutions and Energy Solutions. New containers and a new innovative inter-modal packaging system to transport the radioactive lead were developed and demonstrated during the project. The project also demonstrated the potential contribution of international nuclear recycling activities as a safe, economic and feasible technical option for nuclear decommissioning in the United Kingdom. (authors)

  18. Metabolic fate of radioactive acyclovir in humans

    SciTech Connect

    de Miranda, P.; Good, S.S.; Krasny, H.C.; Connor, J.D.; Laskin, O.L.; Lietman, P.S.

    1982-07-20

    The metabolic fate and the kinetics of elimination of (8-/sup 14/C)acyclovir in plasma and blood was investigated in five cancer patients. Doses of 0.5 and 2.5 mg/kg were administered by one-hour intravenous infusion. Radioactivity was distributed nearly equally in blood and plasma. The plasma and blood concentration-time data were defined by a two-compartment open pharmacokinetic model. The overall mean acyclovir plasma half-life and total body clearance +/- SD were 2.1 +/- 0.5 hours and 297 +/- 53 ml/min/1.73 m2. Binding of acyclovir to plasma proteins was 15.4 +/- 4.4 percent. The radioactive dose was excreted predominantly in the urine (71 to 99 percent) with less than 2 percent excretion in the feces and only trace amounts of radioactivity in the expired air. Reverse-phase high-performance liquid chromatography indicated that 9-carboxymethoxymethylguanine was the only significant urinary metabolite of acyclovir accounting for 8.5 to 14.1 percent of the dose. A minor metabolite (less than 0.2 percent of dose) had the retention time of 8-hydroxy-9-(2-hydroxyethoxymethyl)guanine. Unchanged urinary acyclovir ranged from 62 to 91 percent of the dose. There was no indication of acyclovir cleavage to guanine. The renal clearances of acyclovir were three times higher than the corresponding creatinine clearances.

  19. Radioactive waste management centers: an approach

    SciTech Connect

    Lotts, A.L.

    1980-01-01

    Radioactive waste management centers would satisfy the need for a cost-effective, sound management system for nuclear wastes by the industry and would provide a well integrated solution which could be understood by the public. The future demands for nuclear waste processing and disposal by industry and institutions outside the United States Government are such that a number of such facilities are required between now and the year 2000. Waste management centers can be organized around two general needs in the commercial sector: (1) the need for management of low-level waste generated by nuclear power plants, the once-through nuclear fuel cycle production facilities, from hospitals, and other institutions; and (2) more comprehensive centers handling all categories of nuclear wastes that would be generated by a nuclear fuel recycle industry. The basic technology for radioactive waste management will be available by the time such facilities can be deployed. This paper discusses the technical, economic, and social aspects of organizing radioactive waste managment centers and presents a strategy for stimulating their development.

  20. Integration of Radioactive Material with Microcalorimeter Detectors

    NASA Astrophysics Data System (ADS)

    Croce, M. P.; Bond, E. M.; Hoover, A. S.; Kunde, G. J.; Moody, W. A.; Rabin, M. W.; Bennett, D. A.; Hayes-Wehle, J.; Kotsubo, V.; Schmidt, D. R.; Ullom, J. N.

    2014-09-01

    Microcalorimeter detectors with embedded radioactive material offer many possibilities for new types of measurements and applications. We will discuss the designs and methods that we are developing for precise deposition of radioactive material and its encapsulation in the absorber of transition-edge sensor (TES) microcalorimeter detectors for two specific applications. The first application is total nuclear reaction energy (Q) spectroscopy for nuclear forensics measurements of trace actinide samples, where the goal is determination of ratios of isotopes with Q values in the range of 5-7 MeV. Simplified, rapid sample preparation and detector assembly is necessary for practical measurements, while maintaining good energy resolution. The second application is electron capture spectroscopy of isotopes with low Q values, such as Ho, for measurement of neutrino mass. Detectors for electron capture spectroscopy are designed for measuring energies up to approximately 6 keV. Their smaller heat capacity and physical size present unique challenges. Both applications require precise deposition of radioactive material and encapsulation in an absorber with optimized thermal properties and coupling to the TES. We have made detectors for both applications with a variety of designs and assembly methods, and will present their development.

  1. Method of removing radioactive waste from oil

    SciTech Connect

    Belanger, R.L.

    1986-10-07

    This patent describes a method of removing particulates, radioactive contaminants, and moisture from oil, which consists of: straining out the particulates by passing the oil through a coarse filter screen to a receiving vessel; forming an upper stratum of oil and a lower stratum of sludge, consisting of mud, oil, particulates, and moisture, by heating the upper two-thirds of the receiving vessel; skimming off the stratum of oil from the receiving vessel; transferring the sludge from the receiving vessel to a container; transferring additional separated oil to the receiving vessel; conveying the oil skimmed from the receiving vessel to a mixing vessel; adding an effective amount of Calcium Hypochlorite crystals containing 65% free Chlorine to the mixing vessel to initiate salt formation with the radioactive contaminants; mixing the contents of the mixing vessel for at least ten minutes; transferring the mixture from the mixing vessel to a circulating heater; outputting the mixture from the circulating heater to a second mixing vessel; removing moisture from the oil; and filtering from the oil, the solid radioactive contaminant-salts and residual particulate matter.

  2. Geological problems in radioactive waste isolation

    SciTech Connect

    Witherspoon, P.A.

    1991-01-01

    The problem of isolating radioactive wastes from the biosphere presents specialists in the fields of earth sciences with some of the most complicated problems they have ever encountered. This is especially true for high level waste (HLW) which must be isolated in the underground and away from the biosphere for thousands of years. Essentially every country that is generating electricity in nuclear power plants is faced with the problem of isolating the radioactive wastes that are produced. The general consensus is that this can be accomplished by selecting an appropriate geologic setting and carefully designing the rock repository. Much new technology is being developed to solve the problems that have been raised and there is a continuing need to publish the results of new developments for the benefit of all concerned. The 28th International Geologic Congress that was held July 9--19, 1989 in Washington, DC provided an opportunity for earth scientists to gather for detailed discussions on these problems. Workshop W3B on the subject, Geological Problems in Radioactive Waste Isolation -- A World Wide Review'' was organized by Paul A Witherspoon and Ghislain de Marsily and convened July 15--16, 1989 Reports from 19 countries have been gathered for this publication. Individual papers have been cataloged separately.

  3. Radioactive iodine therapy in cats with hyperthyroidism

    SciTech Connect

    Turrel, J.M.; Feldman, E.C.; Hays, M.; Hornof, W.J.

    1984-03-01

    Eleven cats with hyperthyroidism were treated with radioactive iodine (/sup 131/I). Previous unsuccessful treatments for hyperthyroidism included hemithyroidectomy (2 cats) and an antithyroid drug (7 cats). Two cats had no prior treatment. Thyroid scans, using technetium 99m, showed enlargement and increased radionuclide accumulation in 1 thyroid lobe in 5 cats and in both lobes in 6 cats. Serum thyroxine concentrations were high and ranged from 4.7 to 18 micrograms/dl. Radioactive iodine tracer studies were used to determine peak radioactive iodine uptake (RAIU) and effective and biological half-lives. Activity of /sup 131/I administered was calculated from peak RAIU, effective half-life, and estimated thyroid gland weight. Activity of /sup 131/I administered ranged from 1.0 to 5.9 mCi. The treatment goal was to deliver 20,000 rad to hyperactive thyroid tissue. However, retrospective calculations based on peak RAIU and effective half-life obtained during the treatment period showed that radiation doses actually ranged from 7,100 to 64,900 rad. Complete ablation of the hyperfunctioning thyroid tissue and a return to euthyroidism were seen in 7 cats. Partial responses were seen in 2 cats, and 2 cats became hypothyroid. It was concluded that /sup 131/I ablation of thyroid tumors was a reasonable alternative in the treatment of hyperthyroidism in cats. The optimal method of dosimetry remains to be determined.

  4. Radioactive waste management in the former USSR

    SciTech Connect

    Bradley, D.J.

    1992-06-01

    Radioactive waste materials--and the methods being used to treat, process, store, transport, and dispose of them--have come under increased scrutiny over last decade, both nationally and internationally. Nuclear waste practices in the former Soviet Union, arguably the world's largest nuclear waste management system, are of obvious interest and may affect practices in other countries. In addition, poor waste management practices are causing increasing technical, political, and economic problems for the Soviet Union, and this will undoubtedly influence future strategies. this report was prepared as part of a continuing effort to gain a better understanding of the radioactive waste management program in the former Soviet Union. the scope of this study covers all publicly known radioactive waste management activities in the former Soviet Union as of April 1992, and is based on a review of a wide variety of literature sources, including documents, meeting presentations, and data base searches of worldwide press releases. The study focuses primarily on nuclear waste management activities in the former Soviet Union, but relevant background information on nuclear reactors is also provided in appendixes.

  5. Soils: man-caused radioactivity and radiation forecast

    SciTech Connect

    Gablin, Vassily

    2007-07-01

    Available in abstract form only. Full text of publication follows: One of the main tasks of the radiation safety guarantee is non-admission of the excess over critical radiation levels. In Russia they are man-caused radiation levels. Meanwhile any radiation measurement represents total radioactivity. That is why it is hard to assess natural and man-caused contributions to total radioactivity. It is shown that soil radioactivity depends on natural factors including radioactivity of rocks and cosmic radiation as well as man-caused factors including nuclear and non-nuclear technologies. Whole totality of these factors includes unpredictable (non-deterministic) factors - nuclear explosions and radiation accidents, and predictable ones (deterministic) - all the rest. Deterministic factors represent background radioactivity whose trends is the base of the radiation forecast. Non-deterministic factors represent man-caused radiation treatment contribution which is to be controlled. This contribution is equal to the difference in measured radioactivity and radiation background. The way of calculation of background radioactivity is proposed. Contemporary soils are complicated technologically influenced systems with multi-leveled spatial and temporary inhomogeneity of radionuclides distribution. Generally analysis area can be characterized by any set of factors of soil radioactivity including natural and man-caused factors. Natural factors are cosmic radiation and radioactivity of rocks. Man-caused factors are shown on Fig. 1. It is obvious that man-caused radioactivity is due to both artificial and natural emitters. Any result of radiation measurement represents total radioactivity i.e. the sum of activities resulting from natural and man-caused emitters. There is no gauge which could separately measure natural and man-caused radioactivity. That is why it is so hard to assess natural and man-caused contributions to soil radioactivity. It would have been possible if human activity had led to contamination of soil only by artificial radionuclides. But we can view a totality of soil radioactivity factors in the following way. (author)

  6. Waste minimization for commercial radioactive materials users generating low-level radioactive waste. Revision 1

    SciTech Connect

    Fischer, D.K.; Gitt, M.; Williams, G.A.; Branch, S.; Otis, M.D.; McKenzie-Carter, M.A.; Schurman, D.L.

    1991-07-01

    The objective of this document is to provide a resource for all states and compact regions interested in promoting the minimization of low-level radioactive waste (LLW). This project was initiated by the Commonwealth of Massachusetts, and Massachusetts waste streams have been used as examples; however, the methods of analysis presented here are applicable to similar waste streams generated elsewhere. This document is a guide for states/compact regions to use in developing a system to evaluate and prioritize various waste minimization techniques in order to encourage individual radioactive materials users (LLW generators) to consider these techniques in their own independent evaluations. This review discusses the application of specific waste minimization techniques to waste streams characteristic of three categories of radioactive materials users: (1) industrial operations using radioactive materials in the manufacture of commercial products, (2) health care institutions, including hospitals and clinics, and (3) educational and research institutions. Massachusetts waste stream characterization data from key radioactive materials users in each category are used to illustrate the applicability of various minimization techniques. The utility group is not included because extensive information specific to this category of LLW generators is available in the literature.

  7. Waste minimization for commercial radioactive materials users generating low-level radioactive waste

    SciTech Connect

    Fischer, D.K.; Gitt, M.; Williams, G.A.; Branch, S. ); Otis, M.D.; McKenzie-Carter, M.A.; Schurman, D.L. )

    1991-07-01

    The objective of this document is to provide a resource for all states and compact regions interested in promoting the minimization of low-level radioactive waste (LLW). This project was initiated by the Commonwealth of Massachusetts, and Massachusetts waste streams have been used as examples; however, the methods of analysis presented here are applicable to similar waste streams generated elsewhere. This document is a guide for states/compact regions to use in developing a system to evaluate and prioritize various waste minimization techniques in order to encourage individual radioactive materials users (LLW generators) to consider these techniques in their own independent evaluations. This review discusses the application of specific waste minimization techniques to waste streams characteristic of three categories of radioactive materials users: (1) industrial operations using radioactive materials in the manufacture of commercial products, (2) health care institutions, including hospitals and clinics, and (3) educational and research institutions. Massachusetts waste stream characterization data from key radioactive materials users in each category are used to illustrate the applicability of various minimization techniques. The utility group is not included because extensive information specific to this category of LLW generators is available in the literature.

  8. Magnetic nanostructures: radioactive probes and recent developments

    NASA Astrophysics Data System (ADS)

    Prandolini, M. J.

    2006-05-01

    The miniaturization of magnetic sensors and storage devices down to the nano-scale leads to drastic changes in magnetic phenomena compared with the same devices with a larger size. Excited-nuclear-probe (radioactive probe) techniques are ideal for investigating these new magnetic nanostructures. By observing the magnetic hyperfine fields (and in some cases the electric-field-gradients (EFGs)) at the nuclei of radioactive probes, microscopic information about the magnetic environment of the probes is acquired. The magnetic hyperfine field is particularly sensitive to the s-spin polarization of the conduction electrons and to the orbital magnetic moment of the probe atom. Three methods of inserting radioactive probes into magnetic nanostructures are presented; neutron activation, recoil implantation and 'soft-landing', followed by descriptions of their application to selected examples. In some cases, these methods offer the simultaneous creation and observation of new magnetic materials at the atomic scale. This review focuses firstly on the induced magnetism in noble-metal spacer layers between either ferromagnetic (FM) or FM/antiferromagnetic (AFM) layers in a trilayer structure. Using the method of low-temperature nuclear orientation, the s-spin polarization of noble-metal probes was measured and was found to be very sensitive to the magnetic properties at both the FM and AFM interfaces. Secondly, the recoil implantation of radioactive Fe probes into rare-earth hosts and d-band alloys and subsequent measurement using time-differential perturbed angular distribution offer the possibility of controlling the chemical composition and number of nearest-neighbours. This method was used to prepare local 3d-magnetic clusters in a non-magnetic matrix and to observe their magnetic behaviour. Finally, non-magnetic radioactive probes were 'soft-landed' onto Ni surfaces and extremely lattice-expanded ultrathin Ni films. By measuring the magnetic hyperfine fields and EFGs at 111Cd probes using time-differential perturbed angular correlation (TDPAC), it was possible to distinguish the interaction of Cd probes located at various surface sites, i.e. atop terraces, within terraces, at steps and at corners. These experimental results are compared with the ground-state properties determined by ab initio density-functional theory. This article was invited by Professor S Washburn.

  9. Novel Solvent for the Simultaneous recovery of Radioactive Nuclides from Liquid Radioactive Wastes

    SciTech Connect

    Romanovskiy, Valeriy Nicholiavich; Smirnov, Lgor V.; Babain, Vasiliy A.; Todd, Terry A.; Brewer, Ken N.

    1999-10-07

    The present invention relates to solvents, and methods, for selectively extracting and recovering radionuclides, especially cesium and strontium, rare earths and actinides from liquid radioactive wastes. More specifically, the invention relates to extracting agent solvent compositions comprising complex organoboron compounds, substituted polyethylene glycols, and neutral organophosphorus compounds in a diluent. The preferred solvent comprises a chlorinated cobalt dicarbollide, diphenyl-dibutylmethylenecarbamoylphosphine oxide, PEG-400, and a diluent of phenylpolyfluoroalkyl sulfone. The invention also provides a method of using the invention extracting agents to recover cesium, strontium, rare earths and actinides from liquid radioactive waste.

  10. Environmental Assessment Radioactive Source Recovery Program

    SciTech Connect

    1995-12-20

    In a response to potential risks to public health and safety, the U.S. Department of Energy (DOE) is evaluating the recovery of sealed neutron sources under the Radioactive Source Recovery Program (RSRP). This proposed program would enhance the DOE`s and the U.S. Nuclear Regulatory Commission`s (NRC`s) joint capabilities in the safe management of commercially held radioactive source materials. Currently there are no federal or commercial options for the recovery, storage, or disposal of sealed neutron sources. This Environmental Assessment (EA) analyzes the potential environmental impacts that would be expected to occur if the DOE were to implement a program for the receipt and recovery at the Los Alamos National Laboratory (LANL), Los Alamos, New Mexico, of unwanted and excess plutonium-beryllium ({sup 238}Pu-Be) and americium-beryllium ({sup 241}Am-Be) sealed neutron sources. About 1 kg (2.2 lb) plutonium and 3 kg (6.6 lb) americium would be recovered over a 15-year project. Personnel at LANL would receive neutron sources from companies, universities, source brokers, and government agencies across the country. These neutron sources would be temporarily stored in floor holes at the CMR Hot Cell Facility. Recovery reduces the neutron emissions from the source material and refers to a process by which: (1) the stainless steel cladding is removed from the neutron source material, (2) the mixture of the radioactive material (Pu-238 or Am-241) and beryllium that constitutes the neutron source material is chemically separated (recovered), and (3) the recovered Pu-238 or Am-241 is converted to an oxide form ({sup 238}PuO{sub 2} or {sup 241}AmO{sub 2}). The proposed action would include placing the {sup 238}PuO{sub 2} or {sup 241}AmO{sub 2} in interim storage in a special nuclear material vault at the LANL Plutonium Facility.

  11. Crystal Histories and Crustal Magmas: Insights into Magma Storage from U-Series Crystal Ages

    NASA Astrophysics Data System (ADS)

    Cooper, K. M.

    2014-12-01

    The dynamic processes operating within crustal magma reservoirs control many aspects of the chemical composition of erupted magmas, and crystals in volcanic rocks can provide a temporally-constrained archive of these changing environments. A new compilation of 238U-230Th ages of accessory phases and 238U-230Th-226Ra ages of bulk mineral separates of major phases documents that crystals in individual samples often have ages spanning most of the history of a volcanic center. Somewhat surprisingly, this observation holds for surface analyses as well as interior analyses, indicating that the latest stages of growth took place at different times for different grains. Nevertheless, average ages of surfaces are younger than interiors (as expected), and the dominant surface age population is often within error of eruption age. In contrast to accessory phase ages, less than half of the bulk separate 238U-230Th-226Ra ages for major phases are more than 10 kyr older than eruption. This suggests that major phases may in general reflect a later stage of development of an eruptible magma body than do accessory phases, or that the extent of discordance between ages of major and accessory phases reflects the extent to which a crystal mush was remobilized during processes leading to eruption. Crystal ages are most useful for illuminating magmatic processes when combined with crystal-scale trace-element or isotopic data, and I will present several case studies where such combined data sets exist. For example, at Yellowstone and at Okataina Caldera Complex, New Zealand, the combination zircon surface and interior analyses (of age, Hf isotopic, and trace-element data) with bulk dating and in-situ trace-element and isotopic compositions of feldspar allows a comparison of the early history of storage in a crystal mush with the later history of melt extraction and further crystallization prior to eruption, thus tracking development of erupted magma bodies from storage through eruption.

  12. Food-chain transfer of U-series radionuclides in a northern Saskatchewan aquatic system.

    PubMed

    Swanson, S M

    1985-11-01

    Levels of TotalU, 226Ra, and 210Pb in water, sediments, insects and fish were measured in a stream and a lake affected by U mill effluents and in three uncontaminated systems (one creek and two lakes). Radionuclide levels were significantly elevated in water, sediments and biota at contaminated sites. Radionuclide concentration declined with each successive trophic level due primarily to very low assimilation efficiency. Fish radionuclide concentrations varied with season but did not vary with age or year of sampling. Distribution coefficients were high; therefore, a large proportion of radionuclides entering the systems go to the solid phase. Organisms feeding on or near sediments had higher radionuclide levels than pelagic species. There is a potential for long-term cycling of radionuclides from sediments through food chains due to low flux and sedimentation rates. With the exception of water----insects and water----fish all transfer coefficients (TC) were low, usually less than one. Control TCs were greater than TCs in contaminated areas. Radium-226 and 210Pb TCs declined dramatically at the insect-fish level. Uranium uptake from water by insects and fish was much less than 226Ra or 210Pb uptake. Uptake from sediments was similar for all nuclides in insects but 210Pb sediment-fish TCs differed from 226Ra or U TCs. The critical pathway in the contaminated area was sediments----insects----forage fish----whitefish----man. Estimated internal dose rates to large fish in the contaminated area were 1-2 rad/y. Dose to humans from consumption of one fish serving per week for 1 y was 2% of the International Commission on Radiological Protection (ICRP) annual limit for the general public. PMID:4066338

  13. U-series dating of speleothems from the Sierra del Endrinal (Grazalema Mountains, S Spain).

    PubMed

    Alcaraz-Pelegrina, J M; Martnez-Aguirre, A; Rodrguez-Vidal, J

    2012-10-01

    The uranium-series method is applied to date relic flowstone from karstic mountains in the south of Spain. Geomorphological mapping shows three staircased erosion surfaces with a typical karst landform. Exhumed flowstones fill the surficial palaeosinkholes and open fractures. Some of the samples analysed were impure carbonates consequently the leachate-leachate method was used to obtain activity ratios in the carbonate fraction. The ages obtained range from 34.4 ky to 266 ky and are grouped in four periods: 30-50 ky, 90-110 ky, 150 ky and 230-270 ky. All these periods are related to the warm climate oxygen isotope stages 3 and 5. Practically all locations present secular equilibrium in uranium isotopes. PMID:22854172

  14. U-series evidence for two high Last Interglacial sea levels in southeastern Tunisia

    NASA Astrophysics Data System (ADS)

    Jedoui, Younes; Reyss, Jean-Louis; Kallel, Nejib; Montacer, Mabrouk; Isma??l, Hedi Ben; Davaud, Eric

    2003-02-01

    Pleistocene raised marine deposits in southeastern Tunisia consist of a siliciclastic unit that culminates at +3 m asl, overlain by a carbonate-rich unit with Strombus bubonius that culminates at +5 m asl. 234U/ 238U ratios on fossil Ostraea shells from both units are compatible with a marine origin from the uranium incorporated into the shells and show narrowly clustered 230Th-ages, respectively, between 147 and 110 ka and 141 and 100 ka. The two units were therefore developed during Marine Isotopic Substage 5e (MISs 5e, Last Interglacial). Their heights are comparable to those of contemporaneous marine deposits found in many tectonically stable areas of the world such as in the Bahamas and in Bermuda and can therefore be used as indicators of eustatic changes during the Last Interglacial. It is argued that on the basis of this evidence, the Last Interglacial was characterised by two eustatic maxima.

  15. Sediment transport time measured with U-Series isotopes: Resultsfrom ODP North Atlantic Drill Site 984

    SciTech Connect

    DePaolo, Donald J.; Maher, Kate; Christensen, John N.; McManus,Jerry

    2006-06-05

    High precision uranium isotope measurements of marineclastic sediments are used to measure the transport and storage time ofsediment from source to site of deposition. The approach is demonstratedon fine-grained, late Pleistocene deep-sea sediments from Ocean DrillingProgram Site 984A on the Bjorn Drift in the North Atlantic. The sedimentsare siliciclastic with up to 30 percent carbonate, and dated by sigma 18Oof benthic foraminifera. Nd and Sr isotopes indicate that provenance hasoscillated between a proximal source during the last three interglacialperiods volcanic rocks from Iceland and a distal continental sourceduring glacial periods. An unexpected finding is that the 234U/238Uratios of the silicate portion of the sediment, isolated by leaching withhydrochloric acid, are significantly less than the secular equilibriumvalue and show large and systematic variations that are correlated withglacial cycles and sediment provenance. The 234U depletions are inferredto be due to alpha-recoil loss of234Th, and are used to calculate"comminution ages" of the sediment -- the time elapsed between thegeneration of the small (<_ 50 mu-m) sediment grains in the sourceareas by comminution of bedrock, and the time of deposition on theseafloor. Transport times, the difference between comminution ages anddepositional ages, vary from less than 10 ky to about 300 to 400 ky forthe Site 984A sediments. Long transport times may reflect prior storagein soils, on continental shelves, or elsewhere on the seafloor. Transporttime may also be a measure of bottom current strength. During the mostrecent interglacial periods the detritus from distal continental sourcesis diluted with sediment from Iceland that is rapidly transported to thesite of deposition. The comminution age approach could be used to dateQuaternary non-marine sediments, soils, and atmospheric dust, and may beenhanced by concomitant measurement of 226Ra/230Th, 230Th/234U, andcosmogenic nuclides.

  16. Stratigraphy and U-series geochronology of Late Quaternary megatsunami deposits in Hawaii

    NASA Astrophysics Data System (ADS)

    McMurtry, G. M.; Fryer, G. J.; Tappin, D. R.; Fietzke, J.

    2008-12-01

    Our previous work on Kohala, Hawaii, established that the elevated marine basalt boulder conglomerates found there represent at least one, and probably two megatsunami events in the late Pleistocene. Together with the evidence for giant submarine landslides off western Hawaii island from contemporaneous flank failures of Mauna Loa volcano and identical sequences of submarine terraces off the NW coasts of the islands of Hawaii and Lanai, our hydrodynamic modeling indicates that all islands in the Hawaiian chain must have been affected by these giant waves. We present new dating of these deposits on Hawaii, Lanai and Maui islands together with stratigraphic interpretations of their impacts and origins. We used uranium-series dating of in situ coral clasts to constrain the age of the marine conglomerates, using multiple ion counting- inductively coupled plasma-mass spectrometry techniques, and used 87Sr/86Sr ratios of carbonates to help delineate their origins where marine fossils were absent. Southern Lanai records at least four megatsunami events: at 110 ka, 135 ka, 200 ka, and 240 ka, that likely correspond to the Alika phase 2, Alika phase 1, and two stages of the older South Kona giant submarine landslides. These event dates also correspond to O- isotopic stages 5d, 5e, 7a and 7b, and are in agreement with a changing-climate trigger mechanism for volcanic flank collapse proposed in previous work by ourselves and others. On southern Lanai, there is evidence for two megatsunami deposits in stratigraphic succession in the vicinity of Manele Bay, as well as higher-elevation deposits there containing reworked coral-bearing debris from two older megatsunami events. Coral clasts have been dated from all four events within the high-elevation gullies within Kaluakapo Crater on southern Lanai in this study and Moore and Moore (1988), indicating enormous runups to more than 626 m and wave heights of more than 240 m there that are in agreement with the latest hydrodynamic modeling. There is presently evidence for the 110 ka event on Hawaii, Lanai and West Maui, and for the 200 ka and 240 ka events on the islands of Lanai, Molokai and probably Hawaii. The 135 ka event has so far only been recorded on southern Lanai, but will likely turn up in future work elsewhere.

  17. Food-chain transfer of U-series radionuclides in a northern Saskatchewan aquatic system

    SciTech Connect

    Swanson, S.M.

    1985-11-01

    Levels of Total U, 226Ra, and 210Pb in water, sediments, insects and fish were measured in a stream and a lake affected by U mill effluents and in three uncontaminated systems (one creek and two lakes). Radionuclide levels were significantly elevated in water, sediments and biota at contaminated sites. Radionuclide concentration declined with each successive trophic level due primarily to very low assimilation efficiency. Fish radionuclide concentrations varied with season but did not vary with age or year of sampling. Distribution coefficients were high; therefore, a large proportion of radionuclides entering the systems go to the solid phase. Organisms feeding on or near sediments had higher radionuclide levels than pelagic species. There is a potential for long-term cycling of radionuclides from sediments through food chains due to low flux and sedimentation rates. With the exception of water-insects and water-fish all transfer coefficients (TC) were low, usually less than one. Control TCs were greater than TCs in contaminated areas. Radium-226 and 210Pb TCs declined dramatically at the insect-fish level. Uranium uptake from water by insects and fish was much less than 226Ra or 210Pb uptake. Uptake from sediments was similar for all nuclides in insects but 210Pb sediment-fish TCs differed from 226Ra or U TCs. The critical pathway in the contaminated area was sediments-insects-forage fish-whitefish-man. Estimated internal dose rates to large fish in the contaminated area were 1-2 rad/y. Dose to humans from consumption of one fish serving per week for 1 y was 2% of the International Commission on Radiological Protection (ICRP) annual limit for the general public.

  18. U-series dating of Paleolithic art in 11 caves in Spain.

    PubMed

    Pike, A W G; Hoffmann, D L; Garca-Diez, M; Pettitt, P B; Alcolea, J; De Balbn, R; Gonzlez-Sainz, C; de las Heras, C; Lasheras, J A; Montes, R; Zilho, J

    2012-06-15

    Paleolithic cave art is an exceptional archive of early human symbolic behavior, but because obtaining reliable dates has been difficult, its chronology is still poorly understood after more than a century of study. We present uranium-series disequilibrium dates of calcite deposits overlying or underlying art found in 11 caves, including the United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage sites of Altamira, El Castillo, and Tito Bustillo, Spain. The results demonstrate that the tradition of decorating caves extends back at least to the Early Aurignacian period, with minimum ages of 40.8 thousand years for a red disk, 37.3 thousand years for a hand stencil, and 35.6 thousand years for a claviform-like symbol. These minimum ages reveal either that cave art was a part of the cultural repertoire of the first anatomically modern humans in Europe or that perhaps Neandertals also engaged in painting caves. PMID:22700921

  19. Neanderthal skeleton from Tabun: U-series data by gamma-ray spectrometry.

    PubMed

    Schwarcz, H P; Simpson, J J; Stringer, C B

    1998-12-01

    The Neanderthal hominid Tabun C1, found in Israel by Garrod & Bate, was attributed to either layer B or C of their stratigraphic sequence. We have used gamma-ray spectrometry to determine the 230Th/234U and 231Pa/235U ratios of two bones from this skeleton, the mandible and a femur. The ages calculated from these ratios depend on the uranium uptake history of the bones. Assuming a model of early U (EU) uptake the age of the Tabun C1 mandible is 34+/-5 ka. The EU age of the femur is 19+/-2 ka. The femur may have experienced continuous (linear) U uptake which would give an age of 33+/-4 ka, in agreement with the mandible's EU age, but implies marked inhomogeneity in U uptake history at the site. These new age estimates for the skeleton suggest that it was younger than deposits of layer C. This apparent age is less than those of other Neanderthals found in Israel, and distinctly younger than the ages of the Skhul and Qafzeh burials. This suggests that Neanderthals did not necessarily coexist with the earliest modern humans in the region. All of the more complete Neanderthal fossils from Israel are now dated to the cool period of the last glacial cycle, suggesting that Neanderthals may have arrived in this region as a result of the southward expansion of their habitable range. The young age determined for the Tabun skeleton would suggest that Neanderthals survived as late in the Levant as they did in Europe. PMID:9929173

  20. 2p radioactivity studies with a TPC

    SciTech Connect

    Ascher, P.; Audirac, L.; Blank, B.; Delalee, F.; Demonchy, C. E.; Giovinazzo, J.; Leblanc, S.; Pedroza, J.-L.; Pibernat, J.; Serani, L.; Borcea, C.; Companis, I.; Brown, B. A.; Oliveira Santos, F. de; Grevy, S.; Thomas, J.-C.; Srivastava, P.; and others

    2011-11-30

    After the discovery of two-proton radioactivity in 2002, an important effort has been made in order to observe each emitted particle individually. Energy and angular correlations between the protons should reveal details about the mechanism of this exotic decay mode. In this framework, an experiment has been performed at LISE/GANIL, where the two protons emitted in the decay of {sup 54}Zn have been individually observed for the first time. Angular and energy correlations were determined and allowed a first comparison with theoretical predictions.

  1. ORNL Radioactive Beams for Stellar Explosion Studies

    SciTech Connect

    Smith, Michael S.

    2010-08-12

    At ORNL, we are using unique radioactive beams to measure scattering, transfer, and capture reactions to help understand exploding stars such as novae, supernovae, and X-ray bursts. Recent results have been obtained with beams of {sup 26}Al, {sup 17}F, and {sup 130,132}Sn, utilizing gas targets, silicon strip detectors, and recoil separators. More exciting work is planned at the future FRIB facility. We are also using synergistic nuclear data evaluations and the Computational Infrastructure for Nuclear Astrophysics to investigate the astrophysical impact of our measurements.

  2. Economic feasibility of radioactive scrap steel recycling

    SciTech Connect

    Balhiser, R.; Rosholt, D.; Nichols, F.

    1995-12-31

    The goal of MSE`s Radioactive Scrap Steel (RSS) Recycle Program is to develop practical methods for recycling RSS into useful product. This paper provides interim information about ongoing feasibility investigations that are scheduled for completion by September 1995. The project approach, major issues, and cost projections are outlined. Current information indicates that a cost effective RSS Recycling Facility can be designed, built, and in operation by 1999. The RSS team believes that high quality steel plate can be made from RSS at a conversion cost of $1500 per ton or less.

  3. Particle beam generator using a radioactive source

    DOEpatents

    Underwood, David G. (Naperville, IL)

    1993-01-01

    The apparatus of the present invention selects from particles emitted by a radioactive source those particles having momentum within a desired range and focuses the selected particles in a beam having at least one narrow cross-dimension, and at the same time attenuates potentially disruptive gamma rays and low energy particles. Two major components of the present invention are an achromatic bending and focusing system, which includes sector magnets and quadrupole, and a quadrupole doublet final focus system. Permanent magnets utilized in the apparatus are constructed of a ceramic (ferrite) material which is inexpensive and easily machined.

  4. Particle beam generator using a radioactive source

    DOEpatents

    Underwood, D.G.

    1993-03-30

    The apparatus of the present invention selects from particles emitted by a radioactive source those particles having momentum within a desired range and focuses the selected particles in a beam having at least one narrow cross-dimension, and at the same time attenuates potentially disruptive gamma rays and low energy particles. Two major components of the present invention are an achromatic bending and focusing system, which includes sector magnets and quadrupole, and a quadrupole doublet final focus system. Permanent magnets utilized in the apparatus are constructed of a ceramic (ferrite) material which is inexpensive and easily machined.

  5. Method of treating radioactively contaminated solvent waste

    SciTech Connect

    Jablonski, W.; Mallek, H.; Plum, W.

    1981-07-07

    A method of and apparatus for treating radioactively contaminated solvent waste are claimed. The solvent waste is supplied to material such as peat, vermiculite, diaton, etc. This material effects the distribution or dispersion of the solvent and absorbs the foreign substances found in the solvent waste. Air or an inert gas flows through the material in order to pick up the solvent portions which are volatile as a consequence of their vapor pressure. The thus formed gas mixture, which includes air or inert gas and solvent portions, is purified in a known manner by thermal, electrical, or catalytic combustion of the solvent portions.

  6. Gamma emitting radioactive materials in household dinnerware

    NASA Astrophysics Data System (ADS)

    Khalil, Fawzia Ahmad

    A variety of commonly available household and tableware items and some specialty glass materials commonly found in everyday life were examined for their radioactivity content with two different detection and measurement methods. Dinnerware is produced mainly from clay and sand at high temperatures. Therefore, it should be expected to have some degree of radioactivity. It is also stored in confined places, which permits radon accumulation. The natural radioactivity due to the presence of 238U, 232Th and 40K in dinnerware used in houses was measured. Many dinnerware items from various origins that are sold on the open market were studied. Measurements of specific activities of 238U, 232Th, 40K and 137Cs radionuclide for the samples were carried out. The measurements were made by gamma-ray spectrometry having a high-purity germanium (HpGe) detector connected to a multichannel analyzer and a computer system. The average values of specific activities were (6.03 0.54 to 223.67 22.37 for 238U; 2.87 0.14 to 513.85 15.42 for 232Th; 28.67 2.01 to 2726.70 54.53 for 40K; and 0.592 0.037 to 3.549 0.248 for 137Cs) Bq kg-1, respectively. The glazed samples seemed to contribute most of the activity, although also unglazed samples showed some activity. The absorbed dose rates, radium equivalent and external hazard index were also calculated and tabulated. CR-39 solid-state nuclear track detectors were used to measure the radon track density, exhalation rate and effective radium content for the investigated samples. The exhalation rate was found to vary from 4.376 to 8.144 Bq m-2 d-1. It appears that foreign ceramic products, especially Chinese ones with high uranium content, eventually enter the country. The results from the two methods are compared and their combined uncertainties were estimated from the relation of relative combined variance. In Egypt, no special regulations exist concerning radioactivity in glazed earthenware. On the basis of the previous considerations, it appears that more specific regulations for dinnerware imports are necessary.

  7. Introduction to naturally occurring radioactive material

    SciTech Connect

    Egidi, P.

    1997-08-01

    Naturally occurring radioactive material (NORM) is everywhere; we are exposed to it every day. It is found in our bodies, the food we eat, the places where we live and work, and in products we use. We are also bathed in a sea of natural radiation coming from the sun and deep space. Living systems have adapted to these levels of radiation and radioactivity. But some industrial practices involving natural resources concentrate these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. Other activities, such as flying at high altitudes, expose us to elevated levels of NORM. This session will concentrate on diffuse sources of technologically-enhanced (TE) NORM, which are generally large-volume, low-activity waste streams produced by industries such as mineral mining, ore benefication, production of phosphate Fertilizers, water treatment and purification, and oil and gas production. The majority of radionuclides in TENORM are found in the uranium and thorium decay chains. Radium and its subsequent decay products (radon) are the principal radionuclides used in characterizing the redistribution of TENORM in the environment by human activity. We will briefly review other radionuclides occurring in nature (potassium and rubidium) that contribute primarily to background doses. TENORM is found in many waste streams; for example, scrap metal, sludges, slags, fluids, and is being discovered in industries traditionally not thought of as affected by radionuclide contamination. Not only the forms and volumes, but the levels of radioactivity in TENORM vary. Current discussions about the validity of the linear no dose threshold theory are central to the TENORM issue. TENORM is not regulated by the Atomic Energy Act or other Federal regulations. Control and regulation of TENORM is not consistent from industry to industry nor from state to state. Proposed regulations are moving from concentration-based standards to dose-based standards. So when is TENORM a problem? Where is it a problem? That depends on when, where, and whom you talk to! We will start by reviewing background radioactivity, then we will proceed to the geology, mobility, and variability of these radionuclides. We will then review some of the industrial sectors affected by TENORM, followed by a brief discussion on regulatory aspects of the issue.

  8. Measurements of natural radioactivity inside dandara temple

    NASA Astrophysics Data System (ADS)

    Ahmed, N. K.; Saied, M. H.; Abbady, A.; El-Kamel, A. H.

    1994-07-01

    The natural radioactivities inside Dandara temple are studied by using a NaI(Tl) scintillation spectrometer. The variation of these activities with location is investigated. Average values of the identified radionuclides inside the halls, sanctuary and crypt of the temple are examined. It is estimated that the mean value lies in the range 37.9-90.1 for 212Pb, 70.0-36.0 for 214Bi, 52.6-76.2 for 228Ac, 1.6-5.9 for 208Tl, while for 40K it is 169.3-286.6.

  9. Reusing nylon membranes for radioactive hybridizations.

    PubMed

    Thornbury, D W; Farman, M L

    2000-12-01

    We describe a procedure for recycling nylon hybridization membranes, enabling their repeated use for radioactive Southern hybridization analysis of different DNA samples. Following hybridization and probe removal, nylon membranes containing covalently linked DNAs were treated with 0.55% sodium hypochlorite. This destroyed the DNA, thereby preventing it from participating in further hybridization and enabling the membranes to be used subsequently for binding new DNA samples. With this procedure, we were able to reuse a single membrane as many as 13 times, with no detectable loss in signal. This method was shown to be effective for membranes supplied by three different manufacturers. PMID:11126128

  10. Nuclear structure effects in cluster radioactivity

    NASA Astrophysics Data System (ADS)

    Poenaru, D. N.; Greiner, W.; Hourani, E.; Hussonnois, M.

    1994-09-01

    Hindered or favoured transitions have been experimentally detected in cluster radioactivity of odd-mass nuclei, in a similar way to what has been previously observed in spontaneous fission or in the fine structure of ?-decay. By combining the experimental study with a suitable theoretical description one can develop a powerful method to get direct spectroscopic informations on the deformed states of emitting nuclei. We are analyzing the possibility to explain within a superasymmetric fission model why the14C transition from223Ra toward the first excited state of209Pb is stronger than that toward its ground state.

  11. Electronic Denitration Savannah River Site Radioactive Waste

    SciTech Connect

    Hobbs, D.T.

    1995-04-11

    Electrochemical destruction of nitrate in radioactive Savannah River Site Waste has been demonstrated in a bench-scale flow cell reactor. Greater than 99% of the nitrate can be destroyed in either an undivided or a divided cell reactor. The rate of destruction and the overall power consumption is dependent on the cell configuration and electrode materials. The fastest rate was observed using an undivided cell equipped with a nickel cathode and nickel anode. The use of platinized titanium anode increased the energy requirement and costs compared to a nickel anode in both the undivided and divided cell configurations.

  12. Hanford Site radioactive hazardous materials packaging directory

    SciTech Connect

    McCarthy, T.L.

    1995-12-01

    The Hanford Site Radioactive Hazardous Materials Packaging Directory (RHMPD) provides information concerning packagings owned or routinely leased by Westinghouse Hanford Company (WHC) for offsite shipments or onsite transfers of hazardous materials. Specific information is provided for selected packagings including the following: general description; approval documents/specifications (Certificates of Compliance and Safety Analysis Reports for Packaging); technical information (drawing numbers and dimensions); approved contents; areas of operation; and general information. Packaging Operations & Development (PO&D) maintains the RHMPD and may be contacted for additional information or assistance in obtaining referenced documentation or assistance concerning packaging selection, availability, and usage.

  13. Low radioactivity at the Modane Underground Laboratory

    SciTech Connect

    Loaiza, Pia

    2005-09-08

    The Modane Underground Laboratory, with an overburden of 4800 m.w.e, offers an excellent site for experiments requiring a low-background environment. The laboratory is currently hosting experiments in particle and astroparticle physics and low-level germanium gamma-ray spectrometry activities. This paper sketches the main characteristics, scientific activities and facilities of the laboratory as well as its insertion in the European program ILIAS. Special emphasis is given to the description of the low radioactivity measurements and Germanium detectors.

  14. Ideas and perspectives: truffles not radioactive

    NASA Astrophysics Data System (ADS)

    Büntgen, U.; Jäggi, M.; Stobbe, U.; Tegel, W.; Sproll, L.; Eikenberg, J.; Egli, S.

    2015-11-01

    Although ranging among the most expensive gourmet foods, it remains unclear if Burgundy truffles (Tuber aestivum) accumulate radioactivity at a harmful level comparable to other fungi. Here, we measure the 137Cs in 82 T. aestivum fruitbodies from Switzerland, Germany, France, Italy and Hungary. All specimens reveal insignificant radiocaesium concentrations, thus providing an all clear for truffle hunters and cultivators in Europe as well as dealers and customers from around the world. Our results are particularly relevant in the light of recent cultivation efforts and the fact that forest ecosystems are still highly contaminated with 137Cs, for which mushrooms are the main pathways to human diets.

  15. System for handling and storing radioactive waste

    DOEpatents

    Anderson, J.K.; Lindemann, P.E.

    1982-07-19

    A system and method are claimed for handling and storing spent reactor fuel and other solid radioactive waste, including canisters to contain the elements of solid waste, storage racks to hold a plurality of such canisters, storage bays to store these racks in isolation by means of shielded doors in the bays. This system also includes means for remotely positioning the racks in the bays and an access tunnel within which the remotely operated means is located to position a rack in a selected bay. The modular type of these bays will facilitate the construction of additional bays and access tunnel extension.

  16. Astrophysics experiments with radioactive beams at ATLAS

    SciTech Connect

    Back, B. B.; Clark, J. A.; Pardo, R. C.; Rehm, K. E. Savard, G.

    2014-04-15

    Reactions involving short-lived nuclei play an important role in nuclear astrophysics, especially in explosive scenarios which occur in novae, supernovae or X-ray bursts. This article describes the nuclear astrophysics program with radioactive ion beams at the ATLAS accelerator at Argonne National Laboratory. The CARIBU facility as well as recent improvements for the in-flight technique are discussed. New detectors which are important for studies of the rapid proton or the rapid neutron-capture processes are described. At the end we briefly mention plans for future upgrades to enhance the intensity, purity and the range of in-flight and CARIBU beams.

  17. Radioactive contamination of forests in Poland.

    PubMed

    Mietelski, J W; Macharski, P; Jasi?ska, M; Broda, R

    1994-01-01

    Partial results of a large survey of radioactive contamination in Polish forests are presented. All measurements were performed with low-background gamma spectrometers. The measurement method is briefly described. Activities of 137Cs, 134Cs, 125Sb, 106Ru, 144Ce, 154Eu, 155Eu, and 60Co in A0 and A1 layers of forest litter from all over Poland are determined. The geographical distribution of contamination as well as its origin is discussed. Nonuniform composition of the Chernobyl fallout over Poland is confirmed and documented. PMID:7710892

  18. Some Perspectives on Future Proton Radioactivity Experiments

    SciTech Connect

    Page, R. D.

    2011-11-30

    Understanding the phenomenon of one-proton emission is crucial for addressing the question of the location of the limits of observable nuclei. Much of the current understanding of this radioactive decay process has been developed and refined through measurements of proton emitters above Z = 50, where {approx}30 proton-emitting nuclei have already been discovered and studied. However, despite the great experimental and theoretical efforts over recent years, some important questions remain unanswered. Possibilities for future experiments to tackle some of these issues are considered.

  19. System for disposing of radioactive water

    DOEpatents

    Gotchy, Reginald L.

    1976-01-13

    A system for reducing radioactivity released to the biosphere in the course of producing natural gas from a reservoir stimulated by the detonation of nuclear explosives therein. Tritiated water produced with the gas is separated out and returned to a nuclear chimney through a string of tubing positioned within the well casing. The tubing string is positioned within the well casing in a manner which enhances separation of the water out of the gas and minimizes entrainment of water into the gas flowing out of the chimney.

  20. RECLAMATION OF RADIOACTIVE MATERIAL PACKAGING COMPONENTS

    SciTech Connect

    Abramczyk, G.; Nathan, S.; Loftin, B.; Bellamy, S.

    2011-06-06

    Radioactive material packages are withdrawn from use for various reasons; loss of mission, decertification, damage, replacement, etc. While the packages themselves may be decertified, various components may still be able to perform to their required standards and find useful service. The Packaging Technology and Pressurized Systems group of the Savannah River National Laboratory has been reducing the cost of producing new Type B Packagings by reclaiming, refurbishing, and returning to service the containment vessels from older decertified packagings. The program and its benefits are presented.

  1. Corrosion resistant storage container for radioactive material

    DOEpatents

    Schweitzer, D.G.; Davis, M.S.

    1984-08-30

    A corrosion resistant long-term storage container for isolating high-level radioactive waste material in a repository is claimed. The container is formed of a plurality of sealed corrosion resistant canisters of different relative sizes, with the smaller canisters housed within the larger canisters, and with spacer means disposed between juxtaposed pairs of canisters to maintain a predetermined spacing between each of the canisters. The combination of the plural surfaces of the canisters and the associated spacer means is effective to make the container capable of resisting corrosion, and thereby of preventing waste material from leaking from the innermost canister into the ambient atmosphere.

  2. Corrosion resistant storage container for radioactive material

    DOEpatents

    Schweitzer, Donald G.; Davis, Mary S.

    1990-01-01

    A corrosion resistant long-term storage container for isolating radioactive waste material in a repository. The container is formed of a plurality of sealed corrosion resistant canisters of different relative sizes, with the smaller canisters housed within the larger canisters, and with spacer means disposed between judxtaposed pairs of canisters to maintain a predetermined spacing between each of the canisters. The combination of the plural surfaces of the canisters and the associated spacer means is effective to make the container capable of resisting corrosion, and thereby of preventing waste material from leaking from the innermost canister into the ambient atmosphere.

  3. Radioactive waste disposal via electric propulsion

    NASA Technical Reports Server (NTRS)

    Burns, R. E.

    1975-01-01

    It is shown that space transportation is a feasible method of removal of radioactive wastes from the biosphere. The high decay heat of the isotopes powers a thermionic generator which provides electrical power for ion thrust engines. The massive shields (used to protect ground and flight personnel) are removed in orbit for subsequent reuse; the metallic fuel provides a shield for the avionics that guides the orbital stage to solar system escape. Performance calculations indicate that 4000 kg. of actinides may be removed per Shuttle flight. Subsidiary problems - such as cooling during ascent - are discussed.

  4. Residual radioactive material guidelines: Methodology and applications

    SciTech Connect

    Yu, C.; Yuan, Y.C.; Zielen, A.J.; Wallo, A. III

    1989-01-01

    A methodology to calculate residual radioactive material guidelines was developed for the US Department of Energy (DOE). This methodology is coded in a menu-driven computer program, RESRAD, which can be run on IBM or IBM-compatible microcomputers. Seven pathways of exposure are considered: external radiation, inhalation, and ingestion of plant foods, meat, milk, aquatic foods, and water. The RESRAD code has been applied to several DOE sites to calculate soil cleanup guidelines. This experience has shown that the computer code is easy to use and very user-friendly. 3 refs., 8 figs.

  5. Natural matrix radioactivity standards and reference materials

    NASA Astrophysics Data System (ADS)

    Volchok, Herbert L.; Feiner, Melvin S.

    1984-06-01

    Although the precise definitions of Natural Matrix Standard (NMS) and Natural Matrix Reference Material (NMRM) remain somewhat unclear, few doubt their extreme usefulness in virtually all programs involving measurements of radioactivity. Rigorous quality assurance/quality control is difficult, if not impossible, particularly in studies requiring radiochemical/radiometric analyses of environmental matrices, when lacking good NMSs and NMRMs. A fairly comprehensive range of these materials is now available internationally, at a reasonable cost. Progress on the National Bureau of Standards NMS program as well as EML's Quality Assessment Program are discussed. In addition 99Tc in vegetation is presented as a specific example of the methodology of preparing a NMRM.

  6. System for handling and storing radioactive waste

    DOEpatents

    Anderson, John K. (San Diego, CA); Lindemann, Paul E. (Escondido, CA)

    1984-01-01

    A system and method for handling and storing spent reactor fuel and other solid radioactive waste, including canisters to contain the elements of solid waste, storage racks to hold a plurality of such canisters, storage bays to store these racks in isolation by means of shielded doors in the bays. This system also includes means for remotely positioning the racks in the bays and an access tunnel within which the remotely operated means is located to position a rack in a selected bay. The modular type of these bays will facilitate the construction of additional bays and access tunnel extension.

  7. [Reduction of radioactive cesium content in pond smelt by cooking].

    PubMed

    Nabeshi, Hiromi; Tsutsumi, Tomoaki; Hachisuka, Akiko; Matsuda, Rieko

    2013-01-01

    In Japan, seafood may be eaten raw or after having been cooked in diverse ways. Therefore, it is important to understand the effect of cooking on the extent of contamination with radioactive materials in order to avoid internal exposure to radioactive materials via seafood. In this study, we investigated the changes in radioactive cesium content in pond smelt cooked in four different ways: grilled, stewed (kanroni), fried and soaked (nanbanzuke). The radioactive cesium content in grilled, kanroni and fried pond smelt was almost unchanged compared with the uncooked state. In contrast, radioactive cesium content in nanbanzuke pond smelt was decreased by about 30%. Our result suggests that soaking cooked pond smelt in seasoning is an effective method of reducing the burden radioactive cesium. PMID:24025209

  8. Upgrading the Radioactive Waste Management Infrastructure in Azerbaijan

    SciTech Connect

    Huseynov, A.; Batyukhnova, O.; Ojovan, M.; Rowat, J.

    2007-07-01

    Radionuclide uses in Azerbaijan are limited to peaceful applications in the industry, medicine, agriculture and research. The Baku Radioactive Waste Site (BRWS) 'IZOTOP' is the State agency for radioactive waste management and radioactive materials transport. The radioactive waste processing, storage and disposal facility is operated by IZOTOP since 1963 being significantly upgraded from 1998 to be brought into line with international requirements. The BRWS 'IZOTOP' is currently equipped with state-of-art devices and equipment contributing to the upgrade the radioactive waste management infrastructure in Azerbaijan in line with current internationally accepted practices. The IAEA supports Azerbaijan specialists in preparing syllabus and methodological materials for the Training Centre that is currently being organized on the base of the Azerbaijan BRWS 'IZOTOPE' for education of specialists in the area of safety management of radioactive waste: collection, sorting, processing, conditioning, storage and transportation. (authors)

  9. 49 CFR 172.436 - RADIOACTIVE WHITE-I label.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false RADIOACTIVE WHITE-I label. 172.436 Section 172.436... SECURITY PLANS Labeling 172.436 RADIOACTIVE WHITE-I label. (a) Except for size and color, the RADIOACTIVE WHITE-I label must be as follows: EC02MR91.032 (b) In addition to complying with 172.407,...

  10. "Radio-Active" Learning: Visual Representation of Radioactive Decay Using Dice

    ERIC Educational Resources Information Center

    Klein, Lynda; Kagan, David

    2010-01-01

    The idea of using a dice game to simulate radioactive decay is not new. However, modern pedagogy encourages, if not requires, us to provide multiple representations and visualizations for our students. The advantage of interactive engagement methods also has been made clear. Here we describe a highly visual and interactive use of dice to develop

  11. Karlsruhe Database for Radioactive Wastes (KADABRA) - Accounting and Management System for Radioactive Waste Treatment - 12275

    SciTech Connect

    Himmerkus, Felix; Rittmeyer, Cornelia

    2012-07-01

    The data management system KADABRA was designed according to the purposes of the Cen-tral Decontamination Department (HDB) of the Wiederaufarbeitungsanlage Karlsruhe Rueckbau- und Entsorgungs-GmbH (WAK GmbH), which is specialized in the treatment and conditioning of radioactive waste. The layout considers the major treatment processes of the HDB as well as regulatory and legal requirements. KADABRA is designed as an SAG ADABAS application on IBM system Z mainframe. The main function of the system is the data management of all processes related to treatment, transfer and storage of radioactive material within HDB. KADABRA records the relevant data concerning radioactive residues, interim products and waste products as well as the production parameters relevant for final disposal. Analytical data from the laboratory and non destructive assay systems, that describe the chemical and radiological properties of residues, production batches, interim products as well as final waste products, can be linked to the respective dataset for documentation and declaration. The system enables the operator to trace the radioactive material through processing and storage. Information on the actual sta-tus of the material as well as radiological data and storage position can be gained immediately on request. A variety of programs accessed to the database allow the generation of individual reports on periodic or special request. KADABRA offers a high security standard and is constantly adapted to the recent requirements of the organization. (authors)

  12. "Radio-Active" Learning: Visual Representation of Radioactive Decay Using Dice

    ERIC Educational Resources Information Center

    Klein, Lynda; Kagan, David

    2010-01-01

    The idea of using a dice game to simulate radioactive decay is not new. However, modern pedagogy encourages, if not requires, us to provide multiple representations and visualizations for our students. The advantage of interactive engagement methods also has been made clear. Here we describe a highly visual and interactive use of dice to develop…

  13. Operating radioactive liquid-fed ceramic melter system

    SciTech Connect

    Bjorklund, W.J.; McElroy, J.L.

    1986-02-01

    Under sponsorship of the Department of Energy's Nuclear Waste Treatment Program (NWTP), a high-level radioactive waste vitrification system has been installed in the Radiochemical Engineering Facility at Hanford, Washington. The pilot-scale radioactive vitrification system consists of a melter, canister-handling turntable, glass-level detection system, and supporting waste preparation, off-gas treatment and condensate treatment systems. During the past year, radioactive shakedown testing of all the systems has occurred, preparing it for production-type operation campaigns in 1986. This paper discusses the results of the radioactive shakedown completed in 1985.

  14. [Processing of liquid radioactive waste by RADON Industrial Research Association].

    PubMed

    Panteleev, V I; Dmitriev, S A; Sobolev, I A; Karlin, Iu V; Demkin, V I; Adamovich, D V; Slastennikov, Iu T; Il'in, V A

    2006-01-01

    The authors present experience accumulated by "RADON" Industrial Research Association in treating liquid radioactive waste. According to the presentation, activities of "R ADON" Industrial Research Association develop in three directions--evolving technical means to purify radioactive waters in "RADON" Industrial Research Association, advancing mobile plants to purify radioactive waters in other institutions, elaborating new technologies for liquid radioactive waste purifications within numerous national and international projects and agreements with various organizations (including those associated with nuclear power stations and nuclear submarines). PMID:16568842

  15. Robust technique using an imaging plate to detect environmental radioactivity.

    PubMed

    Isobe, Tomonori; Mori, Yutaro; Takada, Kenta; Sato, Eisuke; Sakurai, Hideyuki; Sakae, Takeji

    2013-04-01

    The Fukushima Daiichi Nuclear Power Plant was severely damaged by the Great East Japan Earthquake on 11 March 2011. Consequently, a large amount of radioactive material was accidentally released. Recently, the focus has been on quantification of environmental radioactive material. However, conventional techniques require complicated and expensive measurement equipment. In this research, the authors developed a simple method to detect environmental radioactive material with an imaging plate (IP). Two specific measurement subjects were targeted: measurements for the depth distribution of radioactive material in soil and surface contamination of a building roof. For the measurement of depth distribution of radioactive material in soil, the authors ascertained that the concentration of environmental radioactivity was highest at 5 cm below the surface, and it decreased with depth. For the measurement of surface contamination of the building roof, the authors created a contamination map of the building roof. The detector developed could contact the ground directly, and unlike other survey meters, it was not influenced by peripheral radioactivity. In this study, the authors verified the feasibility of measurement of environmental radioactivity with an IP. Although the measured values of the IP were relative, further work is planned to perform evaluations of absolute quantities of radioactive material. PMID:23439139

  16. Titanate-based adsorbents for radioactive ions entrapment from water.

    PubMed

    Yang, Dongjiang; Liu, Hongwei; Zheng, Zhanfeng; Sarina, Sarina; Zhu, Huaiyong

    2013-03-21

    This feature article reviews some titanate-based adsorbents for the removal of radioactive wastes (cations and anions) from water. At the beginning, we discuss the development of the conventional ion-exchangeable titanate powders for the entrapment of radioactive cations, such as crystalline silicotitanate (CST), monosodium titanate (MST), peroxotitanate (PT). Then, we specially emphasize the recent progress in the uptake of radioactive ions by one-dimensional (1D) sodium titanate nanofibers and nanotubes, which includes the synthesis and phase transformation of the 1D nanomaterials, adsorption ability (capacity, selectivity, kinetics, etc.) of radioactive cations and anions, and the structural evolution during the adsorption process. PMID:23412572

  17. Radioactive Ion Beam Production Capabilities At The Holifield Radioactive Ion Beam Facility

    NASA Astrophysics Data System (ADS)

    Beene, J. R.; Dowling, D. T.; Gross, C. J.; Juras, R. C.; Liu, Y.; Meigs, M. J.; Mendez, A. J.; Nazarewicz, W.; Sinclair, J. W.; Stracener, D. W.; Tatum, B. A.

    2011-06-01

    The Holifield Radioactive Ion Beam Facility (HRIBF) is a national user facility for research with radioactive ion beams (RIBs) that has been in routine operation since 1996. It is located at Oak Ridge National Laboratory (ORNL) and operated by the ORNL Physics Division. The principal mission of the HRIBF is the production of high quality beams of shortlived radioactive isotopes to support research in nuclear structure physics and nuclear astrophysics. HRIBF is currently unique worldwide in its ability to provide neutron-rich fission fragment beams post-accelerated to energies above the Coulomb barrier for nuclear reactions. HRIBF produces RIBs by the isotope separator on-line (ISOL) technique using a particle accelerator system that consists of the Oak Ridge Isochronous Cyclotron (ORIC) driver accelerator, one of the two Injectors for Radioactive Ion Species (IRIS1 or IRIS2) production systems, and the 25-MV tandem electrostatic accelerator that is used for RIB post-acceleration. ORIC provides a light ion beam (proton, deuteron, or alpha) which is directed onto a thick target mounted in a target-ion source (TIS) assembly located on IRIS1 or IRIS2. Radioactive atoms that diffuse from the target material are ionized, accelerated, mass selected, and transported to the tandem accelerator where they are further accelerated to energies suitable for nuclear physics research. RIBs are transported through a beam line system to various experimental end stations including the Recoil Mass Spectrometer (RMS) for nuclear structure research, and the Daresbury Recoil Separator (DRS) for nuclear astrophysics research. HRIBF also includes two off-line ion source test facilities, one low-power on-line ISOL test facility (OLTF), and one high-power on-line ISOL test facility (HPTL). This paper provides an overview and status update of HRIBF, describes the recently completed 4.7M IRIS2 addition and incorporation of laser systems for beam production and purification, and discusses a proposed replacement of the ORIC driver accelerator.

  18. Electrochemical characterization of grouted radioactive waste

    SciTech Connect

    Gu, J.; Zhu, Z.; Tomkiewicz, M.

    1993-11-01

    Any long-term disposal system of radioactive waste will require monitoring to warn against structural deterioration and leach of the radioactive or hazardous components into the environment. Although the existing methods, based on physical sampling and testing, provide a higher level of confidence in the data, it also results in generation of secondary waste streams and increased exposure to radiation for workers. Therefore, it is highly desirable that a method be developed for remotely sensing the grout. Efforts are focused on the application of an array of long lasting electrodes that will sense the dynamic properties of ions in the grout. The basic unit structure consists of four electrodes through which the authors perform a variety of measurements such as impedance, single frequency conductivity, electrochemical potential, cyclic voltammetry, etc. Grout and other cementitious materials are described within the general context of composite media in which morphology, chemistry and conductivity are interdependent. They describe experimental results that include time evolution over many months of the impedance and electrochemical potential of hydrating (and drying) cement composite and their attempts at interpreting these data in terms of conductivity and dielectric constant of the matrix. Along with the time evolution tests; they have performed the resistivity measurement during simulated deionized water flooding into the dry grout. The leach test experiment is designed to establish possible correlation with present quality verification methods and standard leach test or other such accepted tests.

  19. 25 Years of Radioactive Beams at TRIUMF

    NASA Astrophysics Data System (ADS)

    D'Auria, John M.

    2012-10-01

    It has been 25 years since the first radioactive beams were produced at TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics. These first beams, ^37,38K and ^25Na, were produced using the innovative TISOL (Test Isotope Separator On-Line) prototype facility and started the path to the present ISAC (Isotope Separator and ACcelerator) facility, considered one of the best accelerated radioactive beam facilities in the world today, and the new ARIEL (Advanced Rare IsotopE Laboratory) facility, presently under construction. It is time to acknowledge the role TISOL played in opening this path, and explore some of its achievements during its years of operation. TISOL enabled experiments measuring the decay of very short-lived isotopes, including information needed for energy production in novae, an atom trap to measure neutrino momenta from beta decay, a key experiment in understanding the production of carbon and oxygen in the Universe, and other studies. This presentation will give a short history of TISOL, aspects of its original technical characteristics and a summary of its scientific achievements.

  20. Field tests using radioactive matter 2.

    PubMed

    Rulik, P; Prouza, Z; Hovorka, J; Beckova, V; Cespirova, I; Fronka, A; Helebrant, J; Hulka, J; Kuca, P; Skrkal, J

    2013-04-01

    Results of field tests with explosive dispersal of a radioactive substance (RaS) are presented. The paper deals with tests exploiting artificial obstacles as a continuation and expansion of the tests used in this study performed in free area described previously. The essential goal of the tests was to estimate the distribution of the released RaS in the case of intentional abuse of radioactive sources and to get a set of data applicable to testing physical or mathematical models of propagation. Effects of different geometrical and meteorological conditions on the distribution of dispersed RaS were studied via the assessment of dose rate, surface and volume activities, aerosol mass and activity aerodynamic diameters. The principal results can be summarised as follows: the prevalent proportion of the activity of the radionuclide dispersed by an explosion (born by the blast wave and by air convection) is transferred to the detection system/collecting pads essentially within the first minute. Enhanced aerosol mass concentrations were also detected within the same period. The RaS carried by the blast wave passed through the polygon (50 m) within <1 s. An expected crucial impact of meteorological conditions at the moment of the explosion and shortly after was proved by the tests. PMID:22923250

  1. Crystallization of sodium nitrate from radioactive waste

    SciTech Connect

    Krapukhin, V.B.; Krasavina, E.P. Pikaev, A.K.

    1997-07-01

    From the 1940s to the 1980s, the Institute of Physical Chemistry of the Russian Academy of Sciences (IPC/RAS) conducted research and development on processes to separate acetate and nitrate salts and acetic acid from radioactive wastes by crystallization. The research objective was to decrease waste volumes and produce the separated decontaminated materials for recycle. This report presents an account of the IPC/RAS experience in this field. Details on operating conditions, waste and product compositions, decontamination factors, and process equipment are described. The research and development was generally related to the management of intermediate-level radioactive wastes. The waste solutions resulted from recovery and processing of uranium, plutonium, and other products from irradiated nuclear fuel, neutralization of nuclear process solutions after extractant recovery, regeneration of process nitric acid, equipment decontamination, and other radiochemical processes. Waste components include nitric acid, metal nitrate and acetate salts, organic impurities, and surfactants. Waste management operations generally consist of two stages: volume reduction and processing of the concentrates for storage, solidification, and disposal. Filtration, coprecipitation, coagulation, evaporation, and sorption were used to reduce waste volume. 28 figs., 40 tabs.

  2. 2p radioactivity studied by tracking technique

    NASA Astrophysics Data System (ADS)

    Mukha, Ivan

    2010-06-01

    The recent advance in experimental studies of short-lived exotic nuclei beyond the proton drip line is presented. In particular, in-flight decays of proton-unbound nuclei with picosecond lifetimes can be probed by a novel technique which tracks all decay products precisely, and the decay vertices as well as the angular correlations of the fragments are deduced from the measured trajectories. The corresponding pioneering experiment which identified a previously-unknown isotope 19Mg and its two-proton (2p) radioactivity as well as studied the reference 2p decay of the known isotope 16Ne is described. Systematic studies of other 2p precursors beyond the proton drip line are foreseen with this powerful technique whose sensitivity is larger by factor of 30 in comparison with a conventional invariant-mass method. The 2p radioactivity candidates 30Ar, 34Ca and 26S are discussed. Information about the respective one-proton unbound nuclei can be obtained with this technique by evaluating proton-heavy-fragment correlations. Systematic studies of nuclei beyond the proton drip line, e.g., the well-known proton resonances above the ``waiting points'' in the astrophysical rp-process, 69Br and 73Br are feasible.

  3. Ethernet-based automation in radioactivity measurements

    SciTech Connect

    Schwenker, C.D.; Daly, J.C.; Semkow, T.M.; Kitto, M.E.

    1993-12-31

    The paper describes an integrated radioactivity measurements laboratory involved in a New York State program of monitoring environmental radioactivity and bioassay samples. The laboratory is set up as a comprehensive Ethernet network that integrates radiation detectors, electronics hardware components as well as software automation and communications. Two DEC VAXstations 3100 and 3200 are central to the system. The VAXstation 3100 runs the Canberra/Nuclear Data Genie data-acquisition program. The Acquisition Interface Modules interface the ADCs to the Ethernet. Using the DEC Pathworks, the VAXstation 3100 is also a server for the Ethernet-based network of several 486 and 386 PCs. A designated PC can display the Genie acquisition window, in addition to the main window at VAXstation 3100. Another PC collects data from several NaI detectors using the Oxford/Nucleus DMR-II program. The paper also describe the plans for the future upgrades such as installation of VAXstation 4000/90 as well as interfacing the proportional counters and surface barrier detectors to the network.

  4. 2p radioactivity studied by tracking technique

    SciTech Connect

    Mukha, Ivan

    2010-06-01

    The recent advance in experimental studies of short-lived exotic nuclei beyond the proton drip line is presented. In particular, in-flight decays of proton-unbound nuclei with picosecond lifetimes can be probed by a novel technique which tracks all decay products precisely, and the decay vertices as well as the angular correlations of the fragments are deduced from the measured trajectories. The corresponding pioneering experiment which identified a previously-unknown isotope {sup 19}Mg and its two-proton (2p) radioactivity as well as studied the reference 2p decay of the known isotope {sup 16}Ne is described. Systematic studies of other 2p precursors beyond the proton drip line are foreseen with this powerful technique whose sensitivity is larger by factor of 30 in comparison with a conventional invariant-mass method. The 2p radioactivity candidates {sup 30}Ar, {sup 34}Ca and {sup 26}S are discussed. Information about the respective one-proton unbound nuclei can be obtained with this technique by evaluating proton-heavy-fragment correlations. Systematic studies of nuclei beyond the proton drip line, e.g., the well-known proton resonances above the 'waiting points' in the astrophysical rp-process, {sup 69}Br and {sup 73}Br are feasible.

  5. Fred Hoyle, primary nucleosynthesis and radioactivity

    NASA Astrophysics Data System (ADS)

    Clayton, Donald D.

    2008-10-01

    Primary nucleosynthesis is defined as that which occurs efficiently in stars born of only H and He. It is responsible not only for increasing the metallicity of the galaxy but also for the most abundant gamma-ray-line emitters. Astrophysicists have inappropriately cited early work in this regard. The heavily cited B2FH paper (Burbidge et al., 1957) did not effectively address primary nucleosynthesis whereas Hoyle (Hoyle, 1954) had done so quite thoroughly in his infrequently cited 1954 paper. Even B2FH with Hoyle as coauthor seems strangely to not have appreciated what Hoyle (Hoyle, 1954) had achieved. I speculate that Hoyle must not have thoroughly proofread the draft written in 1956 by E.M. and G.R. Burbidge. The clear roadmap of primary nucleosynthesis advanced in 1954 by Hoyle describes the synthesis yielding the most abundant of the radioactive isotopes for astronomy, although that aspect was unrealized at the time. Secondary nucleosynthesis has also produced many observable radioactive nuclei, including the first gamma-ray-line emitter to be discovered in the galaxy and several others within stardust grains. Primary gamma-ray emitters would have been even more detectable in the early galaxy, when the birth rate of massive stars was greater; but secondary emitters, such as 26Al, would have been produced with smaller yield then owing to smaller abundance of seed nuclei from which to create them.

  6. Testing atomic mass models with radioactive beams

    SciTech Connect

    Haustein, P.E.

    1989-01-01

    Significantly increased yields of new or poorly characterized exotic isotopes that lie far from beta-decay stability can be expected when radioactive beams are used to produce these nuclides. Measurements of the masses of these new species are very important. Such measurements are motivated by the general tendency of mass models to diverge from one another upon excursions from the line of beta-stability. Therefore in these regions (where atomic mass data are presently nonexistent or sparse) the models can be tested rigorously to highlight the features that affect the quality of their short-range and long-range extrapolation properties. Selection of systems to study can be guided, in part, by a desire to probe those mass regions where distinctions among mass models are most apparent and where yields of exotic isotopes, produced via radioactive beams, can be optimized. Identification of models in such regions that have good predictive properties will aid materially in guiding the selection of additional experiments which ultimately will provide expansion of the atomic mass database for further refinement of the mass models. 6 refs., 5 figs.

  7. DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

    SciTech Connect

    NA

    2004-11-22

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) important to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are in the form of tabulated functions with pH and log (line integral) CO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. The output data from this report are fundamental inputs for Total System Performance Assessment for the License Application (TSPA-LA) to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for all of the actinides. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.

  8. The political science of radioactive waste disposal

    SciTech Connect

    Jacobi, L.R. Jr.

    1996-06-01

    This paper was first presented at the annual meeting of the HPS in New Orleans in 1984. Twelve years later, the basic lessons learned are still found to be valid. In 1984, the following things were found to be true: A government agency is preferred by the public over a private company to manage radioactive waste. Semantics are important--How you say it is important, but how it is heard is more important. Public information and public relations are very important, but they are the last thing of concern to a scientist. Political constituency is important. Don`t overlook the need for someone to be on your side. Don`t forget that the media is part of the political process-they can make you or break you. Peer technical review is important, but so is citizen review. Sociology is an important issue that scientists and technical people often overlook. In summary, despite the political nature of radioactive waste disposal, it is as true today as it was in 1984 that technical facts must be used to reach sound technical conclusions. Only then, separately and openly, should political factors be considered. So, what can be said today that wasn`t said in 1984? Nothing. {open_quotes}It`s deja vu all over again.{close_quotes}

  9. Radioactive equilibrium in ancient marine sediments

    USGS Publications Warehouse

    Breger, I.A.

    1955-01-01

    Radioactive equilibrium in eight marine sedimentary formations has been studied by means of direct determinations of uranium, radium and thorium. Alpha-particle counting has also been carried out in order to cross-calibrate thick-source counting techniques. The maximum deviation from radioactive equilibrium that has been noted is 11 per cent-indicating that there is probably equilibrium in all the formations analyzed. Thick-source alpha-particle counting by means of a proportional counter or an ionization chamber leads to high results when the samples contain less than about 10 p.p.m. of uranium. For samples having a higher content of uranium the results are in excellent agreement with each other and with those obtained by direct analytical techniques. The thorium contents that have been obtained correspond well to the average values reported in the literature. The uranium content of marine sediments may be appreciably higher than the average values that have been reported for sedimentary rocks. Data show that there is up to fourteen times the percentage of uranium as of thorium in the formations studied and that the percentage of thorium never exceeds that of uranium. While the proximity of a depositional environment to a land mass may influence the concentration of uranium in a marine sediment, this is not true with thorium. ?? 1955.

  10. Radioactive materials in biosolids : dose modeling.

    SciTech Connect

    Wolbarst, A. B.; Chiu, W. A; Yu, C.; Aiello, K.; Bachmaier, J. T.; Bastian, R. K.; Cheng, J. -J.; Goodman, J.; Hogan, R.; Jones, A. R.; Kamboj, S.; Lenhartt, T.; Ott, W. R.; Rubin, A.; Salomon, S. N.; Schmidt, D. W.; Setlow, L. W.; Environmental Science Division; U.S. EPA; Middlesex County Utilities Authority; U.S. DOE; U.S. NRC; NE Ohio Regional Sewer District

    2006-01-01

    The Interagency Steering Committee on Radiation Standards (ISCORS) has recently completed a study of the occurrence within the United States of radioactive materials in sewage sludge and sewage incineration ash. One component of that effort was an examination of the possible transport of radioactivity from sludge into the local environment and the subsequent exposure of humans. A stochastic environmental pathway model was applied separately to seven hypothetical, generic sludge-release scenarios, leading to the creation of seven tables of Dose-to-Source Ratios (DSR), which can be used in translating from specific activity in sludge into dose to an individual. These DSR values were then combined with the results of an ISCORS survey of sludge and ash at more than 300 publicly owned treatment works, to explore the potential for radiation exposure of sludge workers and members of the public. This paper provides a brief overview of the pathway modeling methodology employed in the exposure and dose assessments and discusses technical aspects of the results obtained.

  11. Radioactivities induced in some LDEF samples

    NASA Technical Reports Server (NTRS)

    Reedy, Robert C.; Moss, Calvin E.; Bobias, S. George; Masarik, Jozef

    1993-01-01

    Radioactivities induced in several Long Duration Exposure Facilities (LDEF) samples were measured by low-level counting at Los Alamos and elsewhere. These radionuclides have activities similar to those observed in meteorites and lunar samples. Some trends were observed in these measurements in terms of profiles in trunnion layers and as a function of radionuclide half-life. Several existing computer codes were used to model the production by the protons trapped in the Earth's radiation belts and by the galactic cosmic rays of some of these radionuclides, Mn-54 and Co-57 in steel, Sc-46 in titanium, and Na-22 in alloys of titanium and aluminum. Production rates were also calculated for radionuclides possibly implanted in LDEF, Be-7, Be-10, and C-14. Enhanced concentrations of induced isotopes in the surfaces of trunnion sections relative to their concentrations in the center are caused by the lower-energy protons in the trapped radiation. Secondary neutrons made by high-energy trapped protons and by galactic cosmic rays produce much of the observed radioactivities, especially deep in an object. Comparisons of the observed to calculated activities of several radionuclides with different half-lives indicate that the flux of trapped protons at LDEF decreased significantly at the end of the mission.

  12. RADIOACTIVE CHEMICAL ELEMENTS IN THE ATOMIC TABLE.

    SciTech Connect

    HOLDEN, N.E.

    2005-08-13

    In the 1949 Report of the Atomic Weights Commission, a series of new elements were added to the Atomic Weights Table. Since these elements had been produced in the laboratory and were not discovered in nature, the atomic weight value of these artificial products would depend upon the production method. Since atomic weight is a property of an element as it occurs in nature, it would be incorrect to assign an atomic weight value to that element. As a result of that discussion, the Commission decided to provide only the mass number of the most stable (longest-lived) known isotope as the number to be associated with these entries in the Atomic Weights Table. As a function of time, the mass number associated with various elements has changed as longer-lived isotopes of a particular elements has been found in nature, or as improved half-life values of an element's isotopes might cause a shift in the longest-lived isotope from one mass number to another. In the 1957 Report of the Atomic Weights Commission, it was decided to discontinue the listing of the mass number in the Atomic Weights Table on the grounds that the kind of information supplied by the mass number is inconsistent with the primary purpose of the Table, i.e., to provide accurate values of ''these constants'' for use in chemical calculations. In addition to the Table of Atomic Weights, the Commission included an auxiliary Table of Radioactive Elements for the first time, where the entry would be the isotope of that element which was most stable, i.e., it had the longest known half-life. In their 1973 report, the Commission noted that the users of the Atomic Weights Table were dissatisfied with the omission of values in the Table for some elements and it was decided to reintroduce the mass number for elements. In their 1983 report, the Commission decided that radioactive elements were considered to lack a characteristic terrestrial isotopic composition, from which an atomic weight value could be calculated to five or more figure accuracy, without prior knowledge of the sample. These elements were again listed in the table with no further information, is., no mass number or atomic weight value. For the elements, which have no stable or long-lived isotopes, the data on radioactive half-lives and relative atomic masses for the nuclides of interest have been evaluated. The values of the half-lives their uncertainties are listed. The uncertainties are given in the last digit quoted of the half-life vale and shown in parentheses. The criteria for consideration of entries in this Table continue to be the same as it has been for over fifty years. It is the same criteria, which are used for all data that are evaluated for inclusion in the Atomic Weight's Table. If a report of data is published in a peer-reviewed journal, that data is evaluated and considered for inclusion in the appropriate table of the biennial report of the Atomic Weights Commission. As better data might become available in the future, the information that is contained in either of the tables may be modified. The information contained in the Table of Radioactive Elements should enable the user to calculate the atomic weight for any sample of radioactive material, which might have a variety of isotopic compositions. The atomic mass values have been taken from the 2003 Atomic Mass Table. Most of these half-lives have already been documented in various sources.

  13. Radioactivity in municipal sewage and sludge.

    PubMed Central

    Martin, J E; Fenner, F D

    1997-01-01

    OBJECTIVE: To determine the environmental consequences of discharges of radioactivity from a large medical research facility into municipal sewage, specifically 131I activity in sewage sludge, and the radiation exposures to workers and the public when sludges are incinerated. METHODS: The authors measured radioactivity levels in the sludge at the Ann Arbor, Michigan, Waste Water Treatment Plant following radioiodine treatments of two patients at the University of Michigan hospital complex and performed a series of calculations to estimate potential radiation doses due to releases of 131I from incineration of sewage sludge. RESULTS: Approximately 1.1% of the radioactive 131I administered therapeutically to patients was measured in the primary sludge. Radiation doses from incineration of sludge were calculated to be 0.048 millirem (mrem) for a worker during a period in which the incinerator filtration system failed, a condition that could be considered to represent maximum exposure conditions, for two nine-hour days. Calculated results for a more typically exposed worker (with the filtration system in operation and a 22-week period of incineration) yielded a committed effective dose equivalent of 0.066 mrem. If a worker were exposed to both conditions during the period of incineration, the dose was calculated to be 0.11 mrem. For a member of the public, the committed effective dose equivalent was calculated as 0.003 mrem for a 22-week incineration period. Exposures to both workers and the public were a very small fraction of a typical annual dose (about 100 mrem excluding radon, or 300 mrem with radon) due to natural background radiation. Transport time to the treatment plant for radioiodine was found to be much longer than that of a normal sewage, possibly due to absorption of iodine by organic material in the sewer lines. The residence time of radioiodine in the sewer also appears to be longer than expected. CONCLUSION: 131I in land-applied sludge presents few health concerns because sufficient decay occurs before it can reach the public however, incineration, which is done in winter months, directly releases the 131I from sewage sludge to the atmosphere, and even though exposures to both workers and the public were found to be considerably lower than 1% of natural background, incineration of sludge in a pathway for public exposure. Although 131I was readily measurable in sewage sludge, only about 1% of the radioione administered to patients was found in the sludge. The fate of the remaining radioactivity has not been established; some may be in secondary and tertiary residuals, but it is quite likely that most passed through the plant and was discharged in dilute concentrations in plant emissions. The behavior of radioiodine and other radioactive materials released into municipal seweage systems, such as those from large medical facilities, is not yet well understood. PMID:9258296

  14. Directions in low-level radioactive waste management: A brief history of commercial low-level radioactive waste disposal

    SciTech Connect

    Not Available

    1994-08-01

    This report presents a history of commercial low-level radioactive waste disposal in the United States, with emphasis on the history of six commercially operated low-level radioactive waste disposal facilities. The report includes a brief description of important steps that have been taken during the last decade to ensure the safe disposal of low-level radioactive waste in the 1990s and beyond. These steps include the issuance of comprehensive State and Federal regulations governing the disposal of low-level radioactive waste, and the enactment of Federal laws making States responsible for the disposal of such waste generated within their borders.

  15. Radioactive Effluents from Nuclear Power Plants Annual Report 2008

    SciTech Connect

    U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation

    2010-12-10

    This report describes radioactive effluents from commercial nuclear power plants (NPPs) in the United States. This information was reported by the licensees for radioactive discharges that occurred in 2008. The report provides information relevant to the potential impact of NPPs on the environment and on public health.

  16. Radioactive Effluents from Nuclear Power Plants Annual Report 2007

    SciTech Connect

    U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation

    2010-12-10

    This report describes radioactive effluents from commercial nuclear power plants (NPPs) in the United States. This information was reported by the licensees for radioactive discharges that occurred in 2007. The report provides information relevant to the potential impact of NPPs on the environment and on public health.

  17. An Excel[TM] Model of a Radioactive Series

    ERIC Educational Resources Information Center

    Andrews, D. G. H.

    2009-01-01

    A computer model of the decay of a radioactive series, written in Visual Basic in Excel[TM], is presented. The model is based on the random selection of cells in an array. The results compare well with the theoretical equations. The model is a useful tool in teaching this aspect of radioactivity. (Contains 4 figures.)

  18. The Identification of Factors Influencing College Students' Attitudes toward Radioactivity.

    ERIC Educational Resources Information Center

    Crater, Harold L., Jr.

    The two basic questions considered in this study were: (1) What attitudes do college students hold toward radioactivity? and (2) What are some characteristics associated with the college students who hold the more favorable attitudes toward radioactivity? The sample studied included 1,205 mostly undergraduate students at the University of Texas at

  19. Transporting Radioactive Waste: An Engineering Activity. Grades 5-12.

    ERIC Educational Resources Information Center

    HAZWRAP, The Hazardous Waste Remedial Actions Program.

    This brochure contains an engineering activity for upper elementary, middle school, and high school students that examines the transportation of radioactive waste. The activity is designed to inform students about the existence of radioactive waste and its transportation to disposal sites. Students experiment with methods to contain the waste and…

  20. Combustible radioactive waste treatment by incineration and chemical digestion

    SciTech Connect

    Stretz, L.A.; Crippen, M.D.; Allen, C.R.

    1980-05-28

    A review is given of present and planned combustible radioactive waste treatment systems in the US. Advantages and disadvantages of various systems are considered. Design waste streams are discussed in relation to waste composition, radioactive contaminants by amount and type, and special operating problems caused by the waste.

  1. Transporting radioactive materials: Q & A to your questions

    SciTech Connect

    Not Available

    1993-04-01

    Over 2 million packages of radioactive materials are shipped each year in the United States. These shipments are carried by trucks, trains, ships, and airplanes every day just like other commodities. Compliance with Federal regulations ensures that radioactive materials are transported safely. Proper packaging is the key to safe shipment. Package designs for radioactive materials must protect the public and the environment even in case of an accident. As the level of radioactivity increases, packaging design requirements become more stringent. Radioactive materials have been shipped in this country for more than 40 years. As with other commodities, vehicles carrying these materials have been involved in accidents. However, no deaths or serious injuries have resulted from exposure to the radioactive contents of these shipments. People are concerned about how radioactive shipments might affect them and the environment. This booklet briefly answers some of the commonly asked questions about the transport of radioactive materials. More detailed information is available from the sources listed at the end of this booklet.

  2. 10 CFR 76.81 - Authorized use of radioactive material.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Authorized use of radioactive material. 76.81 Section 76.81 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.81 Authorized use of radioactive material. Unless otherwise authorized by law, the...

  3. 10 CFR 76.81 - Authorized use of radioactive material.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 2 2011-01-01 2011-01-01 false Authorized use of radioactive material. 76.81 Section 76.81 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.81 Authorized use of radioactive material. Unless otherwise authorized by law, the...

  4. 49 CFR 172.403 - Class 7 (radioactive) material.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Register citations affecting § 172.403, see the List of CFR Sections Affected which appears in the Finding... 49 Transportation 2 2010-10-01 2010-10-01 false Class 7 (radioactive) material. 172.403 Section... REQUIREMENTS, AND SECURITY PLANS Labeling § 172.403 Class 7 (radioactive) material. (a) Unless excepted...

  5. 40 CFR 147.3005 - Radioactive waste injection wells.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... dispose of radioactive waste (as defined in 10 CFR part 20, appendix B, table II, but not including high level and transuranic waste and spent nuclear fuel covered by 40 CFR part 191) shall comply with the... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Radioactive waste injection wells....

  6. 40 CFR 147.3005 - Radioactive waste injection wells.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... dispose of radioactive waste (as defined in 10 CFR part 20, appendix B, table II, but not including high level and transuranic waste and spent nuclear fuel covered by 40 CFR part 191) shall comply with the... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Radioactive waste injection wells....

  7. 40 CFR 147.3005 - Radioactive waste injection wells.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... dispose of radioactive waste (as defined in 10 CFR part 20, appendix B, table II, but not including high level and transuranic waste and spent nuclear fuel covered by 40 CFR part 191) shall comply with the... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Radioactive waste injection wells....

  8. Background radioactivity from natural occurrences: a preliminary review

    SciTech Connect

    Wick, O.J.

    1983-07-01

    This review translates data on concentrations of uranium, thorium, and potassium in the surface and near surface into related radioactivity terms. A summary of total estimated radioactivity due to reported U, Th, and K content of four widespread geological formations, the monazite sands of Appalachia, Chattanooga Shale, Antrim Shale, and Conway Granite, is presented. (ACR)

  9. 10 CFR 20.1005 - Units of radioactivity.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Units of radioactivity. 20.1005 Section 20.1005 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1005 Units of radioactivity. For the purposes of this part, activity is expressed in the special unit...

  10. 10 CFR 20.1005 - Units of radioactivity.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Units of radioactivity. 20.1005 Section 20.1005 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1005 Units of radioactivity. For the purposes of this part, activity is expressed in the special unit...

  11. 10 CFR 20.1005 - Units of radioactivity.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Units of radioactivity. 20.1005 Section 20.1005 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1005 Units of radioactivity. For the purposes of this part, activity is expressed in the special unit...

  12. High-Level Radioactive Waste: Safe Storage and Ultimate Disposal.

    ERIC Educational Resources Information Center

    Dukert, Joseph M.

    Described are problems and techniques for safe disposal of radioactive waste. Degrees of radioactivity, temporary storage, and long-term permanent storage are discussed. Included are diagrams of estimated waste volumes to the year 2000 and of an artist's conception of a permanent underground disposal facility. (SL)

  13. 10 CFR 20.1005 - Units of radioactivity.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Units of radioactivity. 20.1005 Section 20.1005 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1005 Units of radioactivity. For the purposes of this part, activity is expressed in the special unit...

  14. 10 CFR 20.1005 - Units of radioactivity.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Units of radioactivity. 20.1005 Section 20.1005 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION General Provisions § 20.1005 Units of radioactivity. For the purposes of this part, activity is expressed in the special unit...

  15. The Identification of Factors Influencing College Students' Attitudes toward Radioactivity.

    ERIC Educational Resources Information Center

    Crater, Harold L., Jr.

    The two basic questions considered in this study were: (1) What attitudes do college students hold toward radioactivity? and (2) What are some characteristics associated with the college students who hold the more favorable attitudes toward radioactivity? The sample studied included 1,205 mostly undergraduate students at the University of Texas at…

  16. 10 CFR 76.81 - Authorized use of radioactive material.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 2 2012-01-01 2012-01-01 false Authorized use of radioactive material. 76.81 Section 76.81 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety 76.81 Authorized use of radioactive material. Unless otherwise authorized by law, the...

  17. 10 CFR 76.81 - Authorized use of radioactive material.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 2 2013-01-01 2013-01-01 false Authorized use of radioactive material. 76.81 Section 76.81 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety 76.81 Authorized use of radioactive material. Unless otherwise authorized by law, the...

  18. 10 CFR 76.81 - Authorized use of radioactive material.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false Authorized use of radioactive material. 76.81 Section 76.81 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety 76.81 Authorized use of radioactive material. Unless otherwise authorized by law, the...

  19. 40 CFR 147.3005 - Radioactive waste injection wells.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... dispose of radioactive waste (as defined in 10 CFR part 20, appendix B, table II, but not including high level and transuranic waste and spent nuclear fuel covered by 40 CFR part 191) shall comply with the... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Radioactive waste injection wells....

  20. 40 CFR 141.25 - Analytical methods for radioactivity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Analytical methods for radioactivity. 141.25 Section 141.25 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Monitoring and Analytical Requirements § 141.25 Analytical methods for radioactivity....