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1

Characterization of Contaminant Transport Using Naturally-Occurring U-Series Disequilibria  

SciTech Connect

Study the migration of nuclear waste contaminants in subsurface fractured systems using naturally occurring uranium and thorium-series radionuclides as tracers under in-situ physico-chemical and hydrogeologic conditions. Radioactive disequilibria among members of these decay-series nuclides can provide information on the rates of adsorption-desorption and transport of contaminants as well as on fluid transport and rock dissolution in a natural setting.

TEH-LUNG KU

2001-06-01

2

Mantle Melting Processes Beneath Iceland, Assessment from U-series Disequilibria: Implication for Mantle Plume Dynamics  

NASA Astrophysics Data System (ADS)

The existence of mantle plumes has recently been questioned on the basis of geophysical, petrological and geochemical arguments (e.g., Meibom, et al., 2003), although there is a long-standing concession that hotspot volcanoes such as Hawaii or Iceland represent the surface expression of mantle plumes which is hot, buoyant upwelling regions beneath the Earth's lithosphere. In addition to that, the physical structures of plumes are still a subject of questions. For instance, there are models which advocate a relatively cool and broad plume beneath Iceland (Ribe, et al, 1995; Ito, et al., 1996), while others proposed hot and narrow plume beneath central Iceland (Mckenzie, 1984; White, et al., 1995; Wolf et al., 1997). Recently, it has been shown that U-series disequilibria in young hotspot lavas (e.g. Sims, et al., 1999; Kokfelt, et al., 2003; Bourdon, et al., 2005) provide a relative measure of mantle upwelling velocity beneath ocean islands. U and Th fractionation produced during melting is a function of the melting rate. In turn, this parameter should scale with mantle upwelling velocities. Simply stated, a larger melting rate (larger mantle upwelling velocity) yields smaller Th excess relative to the parent nuclide. Using our new data together with previous works we modeled U-series disequilibria measured in recent lavas of Iceland volcanoes. For a reasonable range of mantle porosities (0.01-0.5 %) in a dynamic melting model the upwelling rates show sharp radial increase from 3 to12 cm per year towards the presumed center of Iceland plume (i.e., from Krafla and Eldija to Hekla, Örfæjökull, Tunguhran and Askja), but after about 135 km from the center of the plume the upwelling rates remain constant (2-3 cm per year) in Heimaey, Reykjanes Peninsula and Snæfelsness Peninsula as away from the plume center. We suggest that the incremental upwelling rates towards the center must indeed associated with hot and buoyant upwelling that characterized by higher excess temperature than the surrounding mantle. Our observation is consistent with Wolf et al. (1997) seismic study that shows about 150 km radius of the low velocity anomaly beneath central Iceland, and it gives a strong supporting evidence for models of hot and narrow plume beneath central Iceland. Thus, geochemical data (U series disequilibrium) provide important complementary information that is not available from geophysical and petrological data alone in constraining the physical structure of mantle plumes.

Akalu, T. C.; Kobayashi, K.; Yokoyama, T.; Nakamura, E.

2008-12-01

3

U-series disequilibria in suspended river sediments and implication for sediment transfer time in alluvial plains: The case of the Himalayan rivers  

NASA Astrophysics Data System (ADS)

238U- 234U- 230Th radioactive disequilibria were analyzed in suspended sediments (collected at different depths) from the Ganges River and one of its main tributaries: the Narayani-Gandak River. Results associated with bedload sediment data suggest that uranium-series (U-series) disequilibria in river sediments of the Ganges basin vary with grain size and sampling location. The range of observed U-series disequilibria is explained by a mixing model between a coarse-grained sediment end-member, represented by bedload and bank sediments, and a fine-grained end-member that both originate from Himalaya but undergo different transfer histories within the plain. The coarse-grained sediment end-member transits slowly (i.e. >several 100's ky) in the plain whereas the fine-grained sediment end-member is transferred much faster (<20-25 ky), as indicated by the absence of significant variations in Th isotope composition of the fine-grained sediment end-members. These results show that U-series isotopes can be used to quantify the various transfer times of river sediments of different sizes and infer that there can be an order of magnitude of difference, or more, between the transfer time of suspended and bedload sediments. This underlines that a good knowledge of the proportion of suspended vs. bedload sediments transported in the river is required to accurately assess how fast erosion products are transferred in a catchment and how fast a catchment is likely to respond to external forcing factors.

Granet, M.; Chabaux, F.; Stille, P.; Dosseto, A.; France-Lanord, C.; Blaes, E.

2010-05-01

4

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...

5

U-series disequilibria in volcanic rocks from the Futuna spreading centre (North Fiji Basin)  

NASA Astrophysics Data System (ADS)

The North Fiji basin is the largest active back arc basin of the SW Pacific. It is 12 m.y. old and characterised by a regional upper mantle thermal anomaly (Garel, 2001). The 200Km long Futuna spreading centre (Pelletier et al., 2001) is located west of Futuna and Alofi islands at the border between Lau and North Fijian Basins. This ridge is composed of an axial valley spotted with numerous seamounts. It starts from the north of the Fiji platform (15° 40'S) and ends in the north Fiji transform zone, northwest of the Futuna and Alofi islands (13° 35'S). New U series measurements were performed by TIMS on fresh dredged glassy samples. As the topography of this spreading centre exhibits a peculiar structure, the geochemical signature is also unusual. U and Th concentrations range between 0,0930%, six have a 230Th excess within 25 ± 5% and three have 230Th excess of about 15%. These 230Th excesses are typical of MORB or OIB source melting and not a back arc volcanic processes. It is also symptomatic of a melting in presence of garnet. In the equiline diagram, samples fall on a linear correlation indicating a mixing between two end-members with different Th/Usources ratios. The trend observed in this diagram requires the involvement of an enriched component, likely an EMII component, as defined by the trace elements and Sr-Nd-Pb isotope compositions (Benoit et al., in prep). This trend falls within the OIB field and plots close to Samoan samples analysed by Newman et al. (1984). This trend demonstrates the influence of a melt may be even more enriched than the samples of Savai'i volcano. This EMII melt mixes, within the upper mantle, with the Indian ocean like component as it was already established that it is present below Lau and North Fiji Basins spreading centres (Loock, 1992; Turner et al., 1992; Hickey-Vargas et al, 1995; Zhang et al., 1999).

Le Faouder, A.; Hemond, C.; Benoit, M.; Lagabrielle, Y.; Guivel, C.; Pelletier, B.; Bollinger, C.

2005-05-01

6

210Po-210Pb Dating and U-Series Disequilibria of a Young Basaltic Flow at 10° 44'N EPR  

NASA Astrophysics Data System (ADS)

Divers in the submersible Alvin observed and sampled a very young appearing lava flow at 10° 44'N on the East Pacific Rise (EPR) during a November 2003 biodiversity-funded dive series (DEB-0072695 to J.R. Voight) to the area. The occurrence of the glassy, unsedimented, low-lying graben filling lava flow was unexpected on this magma-starved ridge segment just north of the Clipperton Transform Fault and so 3 dives were used to investigate a 4 km long segment of the flow. Measurements (in progress) of 210Po-210Pb disequilibrium in 4 samples of this lava flow confirm that it is likely extremely young (0-2 months old when the samples were collected). Such age dating is critical here because although this area of the EPR is covered by the SOSUS hydrophone array, data are not available in real time and will not be downloaded until November 2004. The 210Po-210Pb geochronometer (T1/2 =138.4 d) involves a time series of 3 or 4 210Po analyses over the course of 1 year or more, so that our analyses are still ongoing (just 2 data per sample so far) and our results quite preliminary. By meeting time we will have better constrained eruption ages with the addition of more data to the ingrowth curves. Results of other chemical analyses on these same samples are being used to compositionally characterize the lavas and to constrain magmatic process timescales. All 13 of the lavas sampled in Nov 2003 are low MgO (6.5-6.7 wt%) basalts, displaying inter-sample compositional variations (lava flow heterogeneity) at the higher end of the known MORB flow catalogue, in contrast to mafic (8 wt% MgO) and compositionally homogeneous lava flows erupted at the nearby and well-studied 9° 50'N EPR site. 230Th-238U disequilibria in the young 10° 44'N flow clusters around 14-15% 230Th-excesses, which overlaps the high end of the data range from "zero-age" MORB flows at 9° 50'N EPR and the Juan De Fuca Ridge (JDF). Slightly higher excesses, lower (230Th/232Th ), and higher Th/U ratios (2.5-2.6) distinguish our samples from 9° 50'N, suggesting a slightly different source composition (and perhaps melting rate) between the locales. The young flow is variably covered by thick, mucus-rich bacterial mats, sparsely populated by small animals, and had copious bacterial floc issuing from multiple diffuse flow vents ("snowblowers"). Focused high temperature flow vents were not observed (maximum measured fluid temperatures were just 10° C), yet many of the active hydrothermal fluid flows were within lava collapses and were thus difficult to sample.Two hydrothermal vent fluid samples had elevated H2S and Si above background levels, in spite of the near seawater Mg content of the fluids.

van der Zander, I.; Rubin, K. H.; Zierenberg, R. A.; Voight, J. R.; von Damm, K.; McClain, J.

2004-12-01

7

Timescales of magma differentiation from basalt to andesite beneath Hekla Volcano, Iceland: Constraints from U-series disequilibria in lavas from the last quarter-millennium flows  

NASA Astrophysics Data System (ADS)

Measurements of 238U- 230Th- 226Ra disequilibria, Sr-Nd-Pb-Hf isotopes and major-trace elements have been conducted for lavas erupted in the last quarter-millennium at Hekla volcano, Iceland. The volcanic rocks range from basalt to dacite. Most of the lavas (excluding dacitic samples) display limited compositional variations in radiogenic Sr-Nd-Pb-Hf isotopes ( 87Sr/ 86Sr = 0.70319-0.70322; 143Nd/ 144Nd = 0.51302-0.51305; 206Pb/ 204Pb = 19.04-19.06; 207Pb/ 204Pb = 15.53-15.54; 208Pb/ 204Pb = 38.61-38.65; 176Hf/ 177Hf = 0.28311-0.28312). All the samples possess ( 230Th/ 238U) disequilibrium with 230Th excesses, and they show systematic variations in ( 230Th/ 232Th) and ( 238U/ 232Th) ratios. The highest 226Ra excesses occur in the basalt and most differentiated andesite lavas, while some basaltic-andesite lavas have ( 226Ra/ 230Th) ratio that are close to equilibrium. The 238U- 230Th- 226Ra disequilibria variations cannot be produced by simple closed-system fractional crystallization with radioactive decay of 230Th and 226Ra in a magma chamber. A closed-system fractional crystallization model and assimilation and fractional crystallization (AFC) model indicate that the least differentiated basaltic andesites were derived from basalt by fractional crystallization with a differentiation age of ˜24 ± 11 kyr, whereas the andesites were formed by assimilation of crustal material and fractionation of the basaltic-andesites within 2 kyr. Apatite is inferred to play a key role in fractionating the parent-daughter nuclides in 230Th- 238U and 226Ra- 230Th to make the observed variations. Our proposed model is that several batches of basaltic-andesite magmas that formed by fractional crystallization of a basaltic melt from a deeper reservoir, were periodically injected into the shallow crust to form individual magma pockets, and subsequently modifying the original magma compositions via simultaneous assimilation and fractional crystallization. The assimilant is the dacitic melt, which formed by partial melting of the crust.

Chekol, Takele A.; Kobayashi, Katsura; Yokoyama, Tetsuya; Sakaguchi, Chie; Nakamura, Eizo

2011-01-01

8

Are U-Series Disequilibria Transparent to Crustal Processing of Magma? A Case Study at Bezymianny and Klyuchevskoy Volcanoes, Kamchatka, Russia  

Microsoft Academic Search

Disequilibria in the short-lived uranium-series isotopic system can provide timescales of magma production, modification and transport in all tectonic settings. In volcanic arcs, the field has converged on the concept that (238U\\/230Th) and (226Ra\\/230Th) activities greater than one are a result of fluid fluxing from the slab to mantle wedge, and that the preservation of (226Ra\\/230Th) disequilibria requires rapid transport

T. M. Kayzar; B. K. Nelson; O. Bachmann; M. Portnyagin; V. Ponomareva

2010-01-01

9

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

SciTech Connect

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.

Murrell, Michael T.; Ku, Teh-Lung

2001-04-30

10

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

USGS Publications Warehouse

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.

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

1984-01-01

11

Characterization of calculation of in-situ retardation factors of contaminant transport using naturally-radionuclides and rock/water interaction occurring U-Series disequilibria timescales. 1997 annual progress report  

SciTech Connect

'The research is directed toward a quantitative assessment of contaminant transport rates in fracture-rock systems using uranium-series radionuclides. Naturally occurring uranium-and thorium-series radioactive disequilibria will provide information on the rates of adsorption-desorption and transport of radioactive contaminants as well as on fluid transport and rock dissolution in a natural setting. This study will also provide an improved characterization of preferential flow and contaminant transport at the Idaho Environmental and Engineering Lab. (INEEL) site. To a lesser extent, the study will include rocks in the unsaturated zone. The authors will produce a realistic model of radionuclide migration under unsaturated and saturated field conditions at the INEEL site, taking into account the retardation processes involved in the rock/water interaction. The major tasks are to (1) determine the natural distribution of U, Th, Pa and Ra isotopes in rock minerals. sorbed phases on the rocks, and in fluids from both saturated and unsaturated zones at the site, and (2) study rock/water interaction processes using U/Th series disequilibrium and a statistical analysis-based model for the Geologic heterogeneity plays an important role in transporting contaminants in fractured rocks. Preferential flow paths in the fractured rocks act as a major pathway for transport of radioactive contaminants in groundwaters. The weathering/dissolution of rock by groundwater also influences contaminant mobility. Thus, it is important to understand the hydrogeologic features of the site and their impact on the migration of radioactive contaminants. In this regard, quantification of the rock weathering/dissolution rate and fluid residence time from the observed decay-series disequilibria will be valuable. By mapping the spatial distribution of the residence time of groundwater in fractured rocks, the subsurface preferential flow paths (with high rock permeability and short fluid residence time) can be determined.'

Roback, R.; Murrel, M.; Goldstein, S. [Los Alamos National Lab., NM (US). Chemical Science and Technology Div.; Ku, T.L.; Luo, S. [Univ. of Southern California, Los Angeles, CA (US). Dept. of Earth Sciences

1997-01-01

12

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)

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.

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

2010-05-01

13

U-Th-Ra Disequilibria in Lavas from the 2004-2005 Eruption of Mt. St. Helens  

Microsoft Academic Search

Decay of several nuclides in the U-series decay chain occurs on timescales similar to those of a variety of magmatic processes. Thus, analyses of the disequilibria between different parent\\/daughter pairs within this series have been used successfully to trace crystal populations and to describe the time scales of crystallization and magma storage in volcanic systems. Previous work with six samples

C. T. Donnelly; K. M. Cooper

2005-01-01

14

Comparison of U-Th-Ra Disequilibria in multiple crystal populations in lava from the current eruption of Mt. St. Helens  

Microsoft Academic Search

Decay of several nuclides in the U-series decay chain occurs on timescales similar to those of a variety of magmatic processes. Thus, analyses of the disequilibria between different parent\\/daughter pairs within this series have been used successfully to trace crystal populations and to describe the time scales of crystallization and magma storage in volcanic systems. Previous analyses of samples from

C. Donnelly; K. M. Cooper

2006-01-01

15

Variation of U-Th disequilibria in the different size fractions of river sediments: Evidence from the Himalayan river system.  

NASA Astrophysics Data System (ADS)

U-series disequilibria in river sediments have the potential to bring main constrains on the time scale of erosion processes at the scale of watershed. However such a determination requires to characterize and to understand better the variation of 238U-234U-230Th disequilibria in sediment following their nature and/or their size grain. In order to answer this question, we analysed U-Th disequilibria in sediments collected at different depths of the water column of the the Ganges river and one of its main tributary: the Gandak river. We use the natural mineralogical sorting done by the river on the carried sediments to evaluate the sediments U-Th variations as a function of their grain size. These data highlight the significant variations of U-Th disequilibria with the grain size of sediments, implying a difference in the source and transfer time of sediments with their granulometry. For the Ganges river system, it can be proposed from 238U-234U-230Th data that bedload and river-bank sediments originate from Himalayan range and are marked by long transfer time into the plain. By contrast 238U-234U-230Th disequilibria in suspended sediment are explained by a scenario involving an old U gain followed by a recent U-Th fractionation. The U-gain is related to U vegetation recycling in the plain, which is all the more intense than the sediments are far from the high range. Overall, these results indicate that a large proportion of MES in the Ganges river system come from the erosion of soils horizon in the plain, and that their transit time on the plain is short. The detailed study of U-series disequilibria in the different size fraction of river sediments seems therefore important for a correct determination of the transport laws of sediments in alluvial plain.

Chabaux, F.; Granet, M.

2007-12-01

16

Tracing recent mobility in weathering profile by 238U-234U-230Th disequilibria  

NASA Astrophysics Data System (ADS)

Characterization and dating of recent mobility in weathering profiles is important not only to constrain the steps of formation and evolution of weathering profiles but also to identify in weathering profile the presently active processes that control the chemical fluxes carried by rivers from continents to ocean. It is proposed to assess these questions by comparing variations of trace elements and U-series disequilibria in weathering profiles. The approach is applied to the case of an old lateritic profile, the Kaya toposequence, in Burkina Faso (Africa), whose mineralogy and petrology have been studied in details by Leprun (1979). The study has been carried out through the analysis of trace elements and 238U-234U-230Th disequilibria in whole rock samples from two pits in the toposequence, located in contrasted topographical positions. Trace elements data show that the whole toposequence is marked by an intense chemical remobilization, including uranium, from the cap to the lower part of the profile (Dequincey and al., this issue). U-Th disequilibria data outline that all the levels of the profile are affected by recent 238U-234U-230Th fractionations, and that each level of the toposequence is marked by U inputs and outputs. By using a continuous U gain and loss model, and by comparing the variations of U disequilibria in the two study pits one can constrain the dismantling age of the iron cap to about 400 ka. The dismantling is associated with a downward U flux from top to bottom of the profile. U-Th disequilibria in the lower levels give accumulation ages ranging from 0 to 400 ka. The age range and the ranging distribution with depth in the weathering profile imply that the remobilization processes in the toposequence varied with time, with time constants similar to those of climatic variations. Our results show therefore that the present day weathering processes can be very different of the old one. The consequence of this conclusion on the estimate of the erosion rates from the studies on soils or rivers will be discussed.

Chabaux, F.; Dequincey, O.; Leprun, J. C.; Clauer, N.

2003-04-01

17

Modeling of Recent Chemical Mobility in Weathering Profile Through U-Th Disequilibria: Example of the Kaya Lateritic Profiles.  

NASA Astrophysics Data System (ADS)

Determination and dating of recent mobility in weathering profiles is important to constrain their steps of formation and evolution but also to recover the presently active processes that control the chemical fluxes carried by rivers from continents to ocean. Recent studies (1-2) have shown the interest of comparing variations of trace elements and U-series disequilibria in weathering profiles to constrain the nature and the age of recent element mobility in weathering profiles. We pursue this approach and propose a simple modelling of U series disequilibria, using a Monte Carlo inversion approach, to assess the time scale of U mobility in weathering profiles. This approach is exemplified in the case of an old lateritic profile, the Kaya toposequence, in Burkina Faso. It relies on a comparison of U-Th data in both the isochron (230Th/232Th) vs. (238U/232Th) diagram, and the concordia (234U/238U) vs. (230Th/238U) diagram. The method consists in finding, for a given data point, a set of mobility parameters, that provide the same age in the two above diagram. Application of the method to the Kaya lateritic toposequence underscores that the recent chemical mobility in the profile are mainly controlled by the iron-cap dismantling, and would vary with time possibly in response to climatic variations. 1 Dequincey et al. (2002), GCA, 1197-1210; 2 Chabaux et al.(2003), CR Geoscience 335, 1219-1231.

Chabaux, F. J.; Dequincey, O.; Leveque, J.; Pelt, E.

2004-12-01

18

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)

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 (37.6-41.1°S: Nevados de Chillán, 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 Chillán 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 Chillán 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 Chillán may have led to compositions near U-Th equilibrium or with Th-excesses, respectively. Primary Ra-deficits at Chillán, 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.

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

2012-12-01

19

How precise are U-series coral ages?  

Microsoft Academic Search

U-series dating of fossil reef corals is a well established and widely applied technique in paleoclimate research. Many fossil corals, however, show evidence for post-depositional diagenetic alteration, and it is generally accepted that the accuracy of U-series coral ages is more limited due to coral diagenesis than analytical precision. In recent years, three models have been published that try to

Denis Scholz; Augusto Mangini

2007-01-01

20

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

21

Vadose Zone Weathering Rates Inferred from U-Series Disequilibrium  

Microsoft Academic Search

The U-series isotope system can be used to quantify reaction rates in aquifers and thick vadose zone environments. The approach is based on the alpha -recoil of 234Th atoms across grain boundaries, which enriches the pore fluid in 234U. Dissolution of the solid phase releases mainly 238U to the pore fluid, so that the 234U\\/238U activity ratio of the pore

K. Maher; D. J. Depaolo; C. Steefel; J. N. Christensen

2003-01-01

22

Non-destructive gamma spectrometric U-series dating  

NASA Astrophysics Data System (ADS)

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.

Simpson, John J.; Grün, Rainer

23

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

Microsoft Academic Search

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

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

2010-01-01

24

The effects of unidirectional incompatibility on cytonuclear disequilibria in a hybrid zone  

Microsoft Academic Search

Unidirectional incompatibility selection is examined as an alternate mechanism of natural selection to cytoplasmic male sterility\\u000a (CMS) for generating cytonuclear disequilibria. Differences in the dynamics and equilibrium behavior of cytonuclear disequilibria\\u000a between these two cytonuclear selection models may allow for statistical tests of CMS vs. unidirectional incompatibility between\\u000a mating cytotypes. Unlike CMS without migration, unidirectional incompatibility causes the cytoplasmic allele

Robin Dean; Jonathan Arnold

1997-01-01

25

Vadose Zone Weathering Rates Inferred from U-Series Disequilibrium  

NASA Astrophysics Data System (ADS)

The U-series isotope system can be used to quantify reaction rates in aquifers and thick vadose zone environments. The approach is based on the ? -recoil of 234Th atoms across grain boundaries, which enriches the pore fluid in 234U. Dissolution of the solid phase releases mainly 238U to the pore fluid, so that the 234U/238U activity ratio of the pore fluid is a measure of the local ratio of the dissolution U flux to the ? -recoil flux. The interpretation of U-series disequilibrium in weathering environments depends on the ? -recoil flux, which is highly dependent on both the distribution of U and the grain size distribution of the soil. The recoil length of the 234Th atom in a silicate is approximately 700 Å, therefore the fine-grained material, with a greater surface area to volume ratio, contributes a significant amount of the 234U to the porewater. As a result, estimates of the recoil flux based on the mean grain size may under predict the supply of 234U by over an order of magnitude. In order to quantify the reaction rate, this recoil flux must be accurately measured by consideration of the recoil contribution of the fine-grained material, despite the fact that it may only comprise a small fraction of the total mass of the sediment. U concentrations and high precision isotope measurements (234U/238U) of pore fluids, mineral separates, and grain size intervals are used to constrain reaction rates for a 70 m vadose zone core from eastern Washington State. The pore water 234U/238U activity ratios range from 1.04 to 1.20 in the pore fluids, and from 0.94 to 1.0 in the various size fractions. Data from the solid phases is used to construct a predictive model for ? -recoil flux in heterogeneous soil. The calculated recoil loss, which considers each grain size interval, is up to 7 times greater than for a geometric prediction based on the mean grain size. The measured 234U/238U ratios for the vadose zone, in conjunction with the estimates for the a-recoil flux, yield weathering rates of approximately 10-6.4 yr-1, which agree with estimates derived from measurements in granitic soils that are based on mineral abundances and soil age. The data suggest that recoil loss from the fine-grained size fractions in a heterogeneous soil can have a significant impact on the interpretation of U isotopic data.

Maher, K.; Depaolo, D. J.; Steefel, C.; Christensen, J. N.

2003-12-01

26

U-series constraints on mantle melting in the Manus back-arc basin  

NASA Astrophysics Data System (ADS)

Although studies have used U-series isotopes to constrain mantle melting processes beneath mid-ocean ridges, there have been far fewer investigations of back-arc basins, the nature of melting processes there and the role of subduction components from the nearby arc. Lavas dredged from the Manus back-arc basin, located behind the New Britain island arc in Papua New Guinea, display a large diversity of compositions ranging from normal depleted MORB and transitional MORB to typical Back arc basin basalts (BABB) and even extremely enriched BABB (XBABB). We have analysed U-Th-Ra disequilibria in Manus back-arc basin lavas that have previously been analysed for major and trace elements and Sr-Nd-Pb isotope ratios [1]. While most display (230Th/238U) ratios of 0.77-0.95 (brackets indicate activity ratios) a few lavas from the northerly Manus spreading centre and north of the East Rift have small Th excesses with (230Th/238U) < 1.06. (226Ra/230Th) ratios are generally > 1 implying that the lavas are < 8ka old and that no post-eruptive age correction needs to be applied for the U-Th data. The (230Th/238U) ratios do not change systematically with distance from the arc, i.e. we do observe U and Th excess at locations both closer and farther from the arc. However, with increasing distance from the arc, (230Th/232Th), U/Th and Ba/Th all decrease, while Yb concentrations and the Ce/Pb ratios generally increase. We also observe a slight increase of 87Sr/86Sr ratios and decrease of 143Nd/144Nd ~ 200-300 km from the active trench. The combined behaviour of U/Th and Ba/Th provides evidence that the influence of the U-rich 'arc' fluid decreases with increasing distance to the trench, while Ce/Pb ratios indicate that a depleted normal MORB-mantle becomes more important to the north. The zone of higher Sr and lower Nd isotope ratios most likely reflects an increased contribution from the subducted slab, while the relatively depleted isotopic ratios reflect melting of the depleted mantle wedge. The presence of (230Th/238U) < 1 and a decrease of magnitude of U excess with distance from the arc imply that a subduction component becomes less influential with increased distance but still may influence melting process on the order of many 100 kms behind the arc front. 1. Sinton, J.M., et al., Magma genesis and mantle heterogeneity in the Manus back-arc basin, Papua New Guinea. Journal of Petrology, 2003. 44(1): p. 159-195.

Beier, C.; Turner, S. P.; Bach, W.; Niedermeier, D.; Sinton, J.; Gill, J. B.

2008-12-01

27

Modeling U-Series Concordia/Discordia Using STELLA  

NSDL National Science Digital Library

U-Series dating techniques are widely used to determine the absolute ages of some of Earth's oldest rocks, but the concordia/discordia diagram can be quite difficult for students to grasp. In particular, the fact that differing amounts of lead and uranium loss from minerals such as zircon can be used to determine not only the original formation age, but also the time of metamorphism of a rock like granite, is a challenging concept. Making use of previous workers' web-published excercises on radiometric decay, I have produced a STELLA-based lab exercise to develop students' understanding of this important chronologic technique. Students create models of the two isotopic decay systems, 238U --> 206Pb and 235U --> 207Pb, and run these models for 4.5 billion years to create the concordia diagram. They then carry out experiments in which they "add" or "remove" varying amounts of lead or uranium in simulation of metamorphism. The uranium-lead ratios at the end of the simulation allow the discordia line to be plotted on top of the concordia diagram and the ages of original crystallization and metamorphism to be determined from the points of intersection of the two lines. In the course of the lab, students are introduced to the concepts of exponential decay and secular equilibrium as well as modeling concepts such as the creation of if-then statements.

Menking, Kirsten

28

Dispersion of U-series natural radionuclides in stream sediments from Edale, UK.  

PubMed

The spatial distribution of (238)U-series radionuclides, specifically (238)U, (234)U, (230)Th and (226)Ra, has been determined in stream sediments from Edale, Derbyshire, United Kingdom, to explore the behaviour of U-series radionuclides during weathering. For uranium and thorium, two different extraction methods were used, total dissolution with HNO3/HF in a microwave and leaching with aqua regia. This was followed by radiochemical separation using extraction chromatography, then alpha spectrometry measurement. The total radium contents in the sediments were measured using gamma spectrometry, while the leached fraction was measured in the same way as for uranium and thorium. The total sediment content of uranium and thorium ranges from ?10 up to ?200 Bq kg(-1), while the radium specific activity lies between ?15 and 180 Bq kg(-1). In the aqua regia extractions, the uranium and thorium contents are in the range of ?5 to ?100 Bq kg(-1), while the radium specific activities are similar to those measured by total dissolution. All the radionuclides show no correlation with organic matter content. The activity ratios (234)U/(238)U, (230)Th/(238)U and (226)Ra/(238)U were used to determine the degree of radioactive disequilibrium. The data show disequilibrium in most of the sediments, with activity ratios of (234)U/(238)U, (230)Th/(238)U and (226)Ra/(238)U > 1, inconsistent with evolution through straightforward weathering processes. Multivariate cluster analysis based on five variables, the specific activities of (238)U, (234)U, (230)Th, (226)Ra and loss on ignition, was employed to group the data and identify five distinct clusters. There seems to be a link between high radionuclide concentrations and proximity to landslips. PMID:24562972

Siddeeg, Saifeldin M; Bryan, Nicholas D; Livens, Francis R

2014-04-22

29

Effects of Differential Selection in the Sexes on Cytonuclear Polymorphism and Disequilibria  

PubMed Central

We develop a series of models that examine the effects of differential selection between the sexes on cytonuclear polymorphism and disequilibria. A detailed analysis is provided for populations under constant fertility or viability selection censused at life stages without frequency differences in the sexes. We show analytically that cytonuclear disequilibria can be generated de novo if the cytoplasmic and nuclear loci each affect female fitness and there is a nonmultiplicative fitness interaction between them. While computer simulations demonstrate that the majority of disequilibria produced by random selection are transient and small in magnitude, measurable permanent disequilibria can result from selective differences both within and between the two sexes. We derive analytic conditions for a protected cytonuclear polymorphism and use numerical simulations to quantitate the likelihood of obtaining permanent nuclear, cytoplasmic, and cytonuclear variation under various patterns of selection. The numerical analysis identifies special selection regimes more likely to generate disequilibria and maintain cytonuclear polymorphism and reveals a direct correlation to the strength of selection. As a byproduct, our models also provide the first decomposition of the different parental contributions to cytonuclear dynamics and the analytic conditions under which selection can cause cytoplasmic frequency changes or a cytonuclear hitchhiking effect.

Babcock, C. S.; Asmussen, M. A.

1996-01-01

30

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

USGS Publications Warehouse

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.

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

2013-01-01

31

Disequilibrium of the 238U series in basalt  

USGS Publications Warehouse

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.

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

1966-01-01

32

Constraining the timescales of sediment transport in lowland regions using U-series isotopes and morphometric analysis  

NASA Astrophysics Data System (ADS)

The uranium-series (U-series) isotopes are fractionated by chemical and physical weathering, and undergo radioactive decay on timescales relevant to Earth-surface processes (103-106 a). The comminution age technique is based on the disequilibrium between 234U and 238U due to the effects of alpha-decay in fine-grained (< 63 µm) sediment [1]. The calculated comminution age represents the sediment residence time i.e. the time elapsed since a sediment grain was formed by weathering from bedrock, until its eventual deposition. When applied to fluvial systems, this integrates storage in the weathering profile, transit time in the catchment and any temporary storage in alluvial deposits. Despite the majority of global sediment flux to the oceans being derived from slowly eroding lowland regions, still little is known with regard to the dominant controls of erosion in these areas [2]. Here we apply the comminution age technique to the six major catchments in the Gulf of Carpentaria basin (GOC) in northern Australia to investigate the temporal dynamics of erosion in lowland regions. In addition, the geomorphometric properties of the catchments were measured using Geographic Information System techniques (GIS) in order to disentangle topographic vs. climatic controls on the sediment residence time. The sediment residence times calculated from U-series isotopes do not increase linearly downstream which reflects the complicated nature of sediment transport in lowland regions. The sediment residence time appears to be broadly correlated with mean annual precipitation but this relationship is less clear following consideration of the geomorphometric properties of each sub-catchment. This highlights the tendency of geochronological approaches to oversimplify the mechanisms of sediment transport in fluvial systems. Understanding what controls the temporal dynamics of erosion in fluvial system on millennial timescales requires the combination of the hitherto commonly separate approaches of geochronology and geomorphometrics. [1] DePaolo et al. (2006), Earth and Planetary Science Letters, 248, 394-410. [2] Willenbring et al. (2013), Geology 41, 343.

Martin, Ashley; Dosseto, Anthony; Chivas, Allan; May, Jan-Hendrik

2014-05-01

33

U-series evidence for widespread reef development in Shark Bay during the last interglacial  

Microsoft Academic Search

Field observations and U-series ages reveal that Shark Bay, Western Australia (WA) has been inundated by the sea on at least three occasions during the Late Pleistocene\\/Holocene, resulting in a succession of marine deposits around the Bay. The exact age of these deposits has until now been problematic due to a lack of reliable and accurate age data. This study

Michael J. O'Leary; Paul J. Hearty; Malcolm T. McCulloch

2008-01-01

34

Symbiont survival and host-symbiont disequilibria under differential vertical transmission.  

PubMed Central

Interspecific genetic interactions in host-symbiont systems raise intriguing coevolutionary questions and may influence the effectiveness of public health and management policies. Here we present an analytical and numerical investigation of the effects of host genetic heterogeneity in the rate of vertical transmission of a symbiont. We consider the baseline case with a monomorphic symbiont and a single diallelic locus in its diploid host, where vertical transmission is the sole force. Our analysis introduces interspecific disequilibria to quantify nonrandom associations between host genotypes and alleles and symbiont presence/absence. The transient and equilibrium behavior is examined in simulations with randomly generated initial conditions and transmission parameters. Compared to the case where vertical transmission rates are uniform across host genotypes, differential transmission (i) increases average symbiont survival from 50% to almost 60%, (ii) dramatically reduces the minimum average transmission rate for symbiont survival from 0.5 to 0.008, and (iii) readily creates permanent host-symbiont disequilibria de novo, whereas uniform transmission can neither create nor maintain such associations. On average, heterozygotes are slightly more likely to carry and maintain the symbiont in the population and are more randomly associated with the symbiont. Results show that simple evolutionary forces can create substantial nonrandom associations between two species.

Sanchez, M S; Arnold, J; Asmussen, M A

2000-01-01

35

Evaluation of New Geological Reference Materials for U-Series Measurements  

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

36

U-series and radiocarbon analyses of human and faunal remains from Wajak, Indonesia.  

PubMed

Laser ablation U-series dating results on human and faunal bone fragments from Wajak, Indonesia, indicate a minimum age of between 37.4 and 28.5 ka (thousands of years ago) for the whole assemblage. These are significantly older than previously published radiocarbon estimates on bone carbonate, which suggested a Holocene age for a human bone fragment and a late Pleistocene age for a faunal bone. The analysis of the organic components in the faunal material show severe degradation and a positive ?(13)C ratio indicate a high degree of secondary carbonatisation. This may explain why the thermal release method used for the original age assessments yielded such young ages. While the older U-series ages are not in contradiction with the morphology of the Wajak human fossils or Javanese biostratigraphy, they will require a reassessment of the evolutionary relationships of modern human remains in Southeast Asia and Oceania. It can be expected that systematic direct dating of human fossils from this area will lead to further revisions of our understanding of modern human evolution. PMID:23465338

Storm, Paul; Wood, Rachel; Stringer, Chris; Bartsiokas, Antonis; de Vos, John; Aubert, Maxime; Kinsley, Les; Grün, Rainer

2013-05-01

37

U-series dating of the Late Pleistocene mammalian fauna from Wood Quarry (Steetley), Nottinghamshire, UK  

NASA Astrophysics Data System (ADS)

We present the U-series dating of bones from Wood Quarry (Steetley Quarry Cave) using the diffusion-adsorption model to account for uranium uptake. The results give a weighted mean date of 66.8 ± 3.0 kyr, placing this assemblage within or just before Marine Oxygen Isotope Stage 4. The fauna is thought to correlate with the Banwell Bone Cave mammal assemblage-zone of the Early Devensian in Britain. Our results support the idea that this assemblage-zone immediately precedes the assemblage represented nearby at Pin Hole in Creswell Crags which is contemporary with the Mid-Devensian and correlates with MIS 3. Our dates, and dates for the Banwell Bone Cave mammal assemblage-zone from Stump Cross Cavern and evidence from other sites may indicate a longevity for this fauna.

Pike, A. W. G.; Eggins, S.; Grün, R.; Hedges, R. E. M.; Jacobi, R. M.

2005-01-01

38

U-series disequilibrium constraints on magma generation at the Jan Mayen hotspot  

NASA Astrophysics Data System (ADS)

The incompatible element-enriched magma source beneath the Jan Mayen Island hotspot influences melt generation on the adjacent northern Mid-Atlantic Ridge system and likely derives from either a small, local mantle plume, ancient Icelandic plume material emplaced in the mantle source, and/or sub-continental lithospheric mantle remnants emplaced locally by rifting of Greenland. The slow spreading Northern Kolbeinsey and Southern Mohns Ridges are immediately adjacent to Jan Mayen Island. Both have relatively shallow ridge axes, particularly the extremely shallow Eggvin Bank region of the Northern Kolbeinsey Ridge, which host anomalously large central volcanic edifices. We are currently collecting U-series disequilibrium and long-lived radiogenic isotope data for fresh, glassy mid-ocean ridge basalts from the Northern Kolbeinsey and Southern Mohns Ridge segments to better constrain source composition, depth of melting in the garnet peridotite stability field, solid mantle upwelling rates, and the nature of melt extraction beneath those segments. In particular, we are measuring isotopic data for geographically well-located samples collected from hummocky pillow basalt flows within the axial valley of the Northern Kolbeinsey Ridge segment as well as from the large volcanoes on both ridge segments, to further determine the role of the Jan Mayen hotspot in crustal construction on the Mid-Atlantic Ridge. Recently collected data show particularly high strontium isotope ratios consistent with trace element patterns that suggest a distinct local plume located beneath the Jan Mayen hotspot. A plume model for Jan Mayen is supported by new bathymetric imaging of adjacent ridge segments that reveals excess volcanism beneath the large axial volcanoes and a radial distribution of enrichment surrounding Jan Mayen Island. We predict that age-constrained U-series disequilibrium measurements will support active mantle upwelling focused beneath both Jan Mayen Island and the large axial volcanoes.

Rivers, E. R.; Chernow, R.; Elkins, L. J.; Sims, K. W.; Blichert-Toft, J.; Devey, C. W.

2013-12-01

39

U Th Ra disequilibria and the time scale of fluid transfer and andesite differentiation at Arenal volcano, Costa Rica (1968 2003)  

NASA Astrophysics Data System (ADS)

To evaluate the time scale of fluid transfer and andesite differentiation at Arenal volcano in Costa Rica, we have measured trace-element concentrations and U-series disequilibria in whole rocks and mineral separates (pyroxene, plagioclase, magnetite) from lavas of the current eruption (1968 to 2003) by HR-ICP-MS, TIMS and PIMMS techniques. Whole rock and mineral separate analyses show a small but measurable variation in ( 230Th)/( 232Th) (1.10 to 1.18). In contrast, ( 230Th)/( 238U) range from 0.91 to 1.04 reflecting the moderate spread in Th/U. Stage 1 (1968-1971) whole rocks and mineral separates have both higher ( 230Th)/( 232Th) and ( 238U)/( 232Th) than to younger stage 2 lavas (1971 to present), which have lower, nearly constant ( 230Th)/( 232Th) and lower, slightly variable ( 238U)/( 232Th). 226Ra excesses exist in both whole rocks and mineral separates with ( 226Ra)/( 230Th) ranging between 0.94 and 4.8. Whole rock ( 226Ra)/( 230Th) are largest early in the eruption and decrease in the later lavas, which are influenced by newer recharge material. 238U- 230Th whole rock and mineral data produce an inclined array on an equiline diagram, which we interpret to represent progressive melting of a variably fluxed mantle wedge and a Nicaraguan sediment component, and subsequent mixing. 238U- 230Th internal isochrons suggest that minerals grew instantaneously with respect to the half-life of 230Th. Whole rock and mineral separate ( 226Ra)/( 230Th) data indicate that melts were produced, transported, differentiated and erupted in < 8 kyr. Mineral ( 226Ra)/Ba-( 230Th)/Ba model ages are calculated and corrected for melt inclusions and glass adherents in the mineral fractions, and for the differential partitioning of Ra and Ba. Plagioclase model ages and 238U- 230Th isochron ages suggest that plagioclase could be as young as a few years or as old as several centuries upon eruption.

Tepley, Frank J.; Lundstrom, Craig C.; Gill, James B.; Williams, Ross W.

2006-09-01

40

Determination of transfer time for sediments in alluvial plains using 238U-234U-230Th disequilibria: The case of the Ganges river system  

NASA Astrophysics Data System (ADS)

An approach to deriving the transfer time of sediments within alluvial plains by using the variation of the U-series nuclides in sediments collected along rivers is presented in this article and discussed in the light of new data from samples from different locations within the Ganges watershed and its outlet. These data indicate that the upstream-downstream variation of 238U-234U-230Th disequilibria in the sediments, with different variation trends for suspended and coarse-grained sediments, is probably a general feature of all Himalayan rivers flowing across the Indo-Gangetic plain. The data therefore confirm the occurrence of very different transfer times within the plain, depending on the sediments granulometry, with much shorter transfer time for the fine-grained (a few ky or less) than for the coarse-grained sediments (100 ky or more). A new solving approach, using a parallel stochastic Quantum-behaved Particle Swarm Optimization (p-QPSO), has been developed for identifying the unknown parameters of the model necessary for the determination of the transfer time. The data of sediments collected at the Ganges outlet show significant variations of the 234U/230Th activity ratios for the fine-grained sediment end-member collected in 2004 and 2008. Such variations indicate that the fine-grained sediments transit quickly (a year or less) within the plain. The highly variable activity ratios might be the result of quickly changing weathering intensities. Conversely, the U-Th variations observed for the 2004 and 2008 bedload from the Ganges basin cannot result from a short sedimentary transfer time. They probably result from the dredge sampling procedure, which might be influenced by local placer effects controlling the abundance of U and Th carrying minerals. Dredging may not allow the sampling of a representative bedload, hence it may cause an artificial mineralogical and, therefore, an U-Th variability for bedload sediments collected at different periods. At this stage, the transfer time uncertainty induced by this variability is difficult to assess.

Chabaux, François; Blaes, Estelle; Granet, Mathieu; Roupert, Raphaël di Chiara; Stille, Peter

2012-11-01

41

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

SciTech Connect

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.

Stein, M.; Wasserburg, G.J.; Chen, J.H. (California Inst. of Tech., Pasadena (United States)); Lajoie, K.R. (Geological Survey, Menlo Park, CA (United States))

1991-12-01

42

Properties of Natural Radiation and Radioactivity  

Microsoft Academic Search

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,

Strom; Daniel J

2009-01-01

43

U-series dating of co-seismic gypsum and submarine paleoseismology of active faults in Northern Chile (23°S)  

Microsoft Academic Search

The convergence of the Nazca and South American plates along the subduction margin of the central Andes results in large subduction earthquakes and tectonic activity along major fault systems. Despite its relevance, the paleoseismic record of this region is scarce, hampering our understanding about the relationship between the Andes building and earthquake occurrence. In this study, we used the U-series

Gabriel Vargas; Carlos Palacios; Martin Reich; Shangde Luo; Chuan-Chou Shen; Gabriel González; Yi-Chen Wu

2011-01-01

44

Limited diffusion of U-series radionuclides at depth in deep-sea sediments  

Microsoft Academic Search

LONG-TERM radionuclide mobility is a primary concern for evaluating options for the disposal of radioactive waste. Information relevant to the long timescales necessary may be obtained from natural radionuclides. Here we examine a characteristic irregular profile of uranium concentration with depth, in deep-sea turbidite units more than 500,000 years old. This is enough time either for secular equilibrium to have

S. Colley; J. Thomson

1990-01-01

45

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

PubMed

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

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

2003-01-01

46

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

USGS Publications Warehouse

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.

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

2002-01-01

47

High-precision U-series measurements of more than 500,000 year old fossil corals  

Microsoft Academic Search

Robust, independent age constraints on the absolute timing of climate events based on the U-series dating of fossil coral are sparse before the last glacial cycle. Using multiple-collector inductively coupled plasma mass spectrometry with multiple-Faraday protocols, we are able to date ?600 ka samples with an uncertainty of better than ±15 ka (2?), representing a three-fold improvement in precision compared with previous

Morten B. Andersen; Claudine H. Stirling; Emma-Kate Potter; Alex N. Halliday; Steven G. Blake; Malcolm T. McCulloch; Bridget F. Ayling; Michael O'Leary

2008-01-01

48

Evaluating U-series tools for weathering rate and duration on a soil sequence of known ages  

NASA Astrophysics Data System (ADS)

Four soil profiles of known age (40, 250, 600 and 3000 ka) from the Merced soil chronosequence in California were analysed for U and Th isotopes, and for major- and trace-element compositions, to test the assumption that leaching of U-series isotopes is a first order process with an invariant rate constant, as frequently assumed when applying this isotopic tool to determine weathering duration and sediment residence time. Average (230Th/238U) values for each profile decrease from a high of 1.28 in the youngest soil (40 ka) to 1.09, 0.99 and 0.98 in the 250 ka, 600 ka and 3000 ka soils respectively. (234U/238U) values also show variation across the 4 soils. The simultaneous variation in (230Th/238U) and (234U/238U) cannot be explained by a first-order kinetic model with invariant rate constants and instead requires that leaching coefficients for the U-series isotopes change with time. The observed data is consistent with a two-stage model that reflects an initial period of fast leaching of U and Th from a readily weathered soil pool (such as grain boundaries or defects), followed by slow leaching from a more resistant soil pool. Application of such a two-stage model may lead to significantly shorter calculated timescales of weathering than those obtained by the widely applied single-stage model of U-series weathering, which assumes no change in leaching coefficients over time. The results of this study have wide implications for published and future use of U-series tools in weathering studies.

Keech, Andrew R.; West, A. Joshua; Pett-Ridge, Julie C.; Henderson, Gideon M.

2013-07-01

49

Internal tides and sediment dynamics in the deep sea—Evidence from radioactive 234Th\\/ 238U disequilibria  

Microsoft Academic Search

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

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

2008-01-01

50

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

NASA Astrophysics Data System (ADS)

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 -3to 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 some way a poorly documented early phase of the last interglacial sea level high stand.

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

1991-12-01

51

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

NASA Astrophysics Data System (ADS)

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.

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

2002-12-01

52

Dacite formation at Ilopango Caldera, El Salvador: U-series disequilibrium and implications for petrogenetic processes and magma storage time  

NASA Astrophysics Data System (ADS)

Ilopango Caldera was formed ˜1810 years ago by eruption of the Tierra Blanca Joven (TBJ) dacite (70 km3) in central El Salvador. A subsequent eruption in 1880 produced a cluster of dacite domes in the center of Lago Ilopango that contain olive-bearing enclaves of basaltic andesite. The purpose of this study is to use trace element, isotope, and U-series data from the TBJ and 1880 eruptions to assess petrogenesis and the timescale of magma storage. We find that although the range of trace element data in the TBJ dacite can be reproduced by simple crystal fractionation of a plagioclase- and amphibole-rich mineral assemblage, the87Sr/86Sr and 207Pb/204Pb data suggest that the 1880 basaltic andesite enclave has a different source than the dacites. This is consistent with U-series data that show the TBJ dacites have lower (230Th/232Th) than the 1880 basaltic andesite enclave (1.5 versus 1.6, respectively). All Ilopango rocks have 230Th excesses, and the range in (238U/232Th) of the TBJ dacites can be modeled by crystal fractionation of a mineral assemblage including accessory zircon and allanite from a magma that is similar in composition to the enclave. Mineral isochrons yield crystallization ages of <10,000 years, and disequilibrium (226Ra/230Th) values suggest a similarly short residence time. Our data suggest that the large volumes of erupted dacite at Ilopango Caldera are generated very rapidly.

Garrison, Jennifer M.; Reagan, Mark K.; Sims, Kenneth W. W.

2012-06-01

53

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

SciTech Connect

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.

Schaefer, S.J.; Williams, S.N. (Arizona State Univ., Tempe (United States)); Sturchio, N.C. (Argonne National Lab., IL (United States)); Murrell, M.T. (Los Almos National Lab., NM (United States))

1993-03-01

54

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

USGS Publications Warehouse

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.

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

55

U-series dating of co-seismic gypsum and submarine paleoseismology of active faults in Northern Chile (23°S)  

NASA Astrophysics Data System (ADS)

The convergence of the Nazca and South American plates along the subduction margin of the central Andes results in large subduction earthquakes and tectonic activity along major fault systems. Despite its relevance, the paleoseismic record of this region is scarce, hampering our understanding about the relationship between the Andes building and earthquake occurrence. In this study, we used the U-series disequilibrium method to obtain absolute ages of paleoearthquake events associated with normal displacements along the active Mejillones and Salar del Carmen faults in the Coastal Range of the Atacama Desert of northern Chile. The 230Th- 234U disequilibrium ages in co-seismic gypsum salts sampled along the fault traces together with marine evidences indicate that earthquakes occurred at ca. 29.7 ± 1.7 ka, 11 ± 4 ka and 2.4 ± 0.8 ka. When coupled with paleoseismic marine and radiocarbon ( 14C) records in the nearby Mejillones Bay evidencing large dislocations along the Mejillones Fault, the geochronological dataset presented here is consistent with the notion that gypsum salts formed during large earthquakes as a result of co-seismic dilatancy pumping of saline waters along the major faults. Based on maximum observed cumulative vertical offsets in the studied faults, this phenomena could have occurred episodically at a rate in the order of 1:40 to 1:50 with respect to the very large subduction earthquakes during the latest Pleistocene-Holocene period. The results presented here reveal that the U-series disequilibrium method can be successfully applied to date the gypsum salts deposited along faults during seismic events, and therefore directly constrain the age of large paleoearthquakes in hyperarid and seismically active zones.

Vargas, Gabriel; Palacios, Carlos; Reich, Martin; Luo, Shangde; Shen, Chuan-Chou; González, Gabriel; Wu, Yi-Chen

2011-01-01

56

MOD-AGE - an algorithm for age-depth model construction; U-series dated speleothems case study  

NASA Astrophysics Data System (ADS)

We present MOD-AGE - a new system for chronology construction. MOD-AGE can be used for profiles that have been dated by different methods. As input data, the system uses the following basic measurements: activities, atomic ratios or age, as well as depth measurement. Based on probability distributions describing the measurement results, MOD-AGE estimates the age~depth relation and its confidence bands. To avoid the use of difficult-to-meet assumptions, MOD-AGE uses nonparametric methods. We applied a Monte Carlo simulation to model age and depth values based on the real distribution of counted data (activities, atomic ratios, depths etc.). Several fitting methods could be applied for estimating the relationships; based on several tests, we decide to use LOESS method (locally weighted scatterplot smoothing). The stratigraphic correction procedure applied in the MOD-AGE program uses a probability calculus, which assumes that the ages of all the samples are correctly estimated. Information about the probability distribution of the samples' ages is used to estimate the most probable sequence that is concordant according to the superposition rule. MOD-AGE is presented as a tool for the chronology construction of speleothems that have been analyzed by the U-series method, and it is compared to the StalAge algorithm presented by D. Scholtz and D.L Hoffmann (2011). Scholtz, D., Hoffmann, D. L., 2011. StalAge - An algorithm designed for construction of speleothem age models. Quaternary Geochronology 6, 369-382.

Hercman, H.; Pawlak, J.

2012-04-01

57

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

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

58

Constraints on thermal histories of magmas from combined U-series crystal ages, trace-element diffusion, and textural information  

NASA Astrophysics Data System (ADS)

Developing a better understanding of the thermal and chemical evolution of magmas within crustal reservoirs has implications both in terms of the mechanisms of generation of chemically diverse magmas and in terms of the development, size and longevity of bodies of eruptible magma. The physical and thermal states of the system are intimately linked, going from mostly liquid to mushy to potentially solid or almost-solid systems as a function largely of temperature. Crystal-scale records show evidence of long-term storage and recycling of crystals within a reservoir system, but the extent to which storage of these antecrysts occurs in mostly-liquid vs. mostly-solid or solid bodies is unclear. Numerical models can provide insights into thermal histories at a reservoir scale, and crystal and liquid thermometry can provide insights into the thermal state of the crystals at snapshots in time, but developing thermal histories from the record in erupted products has been elusive. We present a new approach to quantifying thermal histories of magma bodies using the crystal record by combining information from multiple analytical approaches. U-series crystal ages provide the total time since crystals grew (albeit averaged). In contrast, trace-element zoning provides an uppper limit to the duration of storage at high temperatures, and crystal sizes and CSDs provide insights into the total growth time of crystals (modified by dissolution). Thus, by combining information from all of these sources, we can link the crystal growth and diffusion ages to thermal states and therefore constrain thermal histories. We use recent eruptive products at Mt Hood as a case study, building off of previous 238U-230Th-226Ra crystal age, CSD, and diffusion modeling results. 230Th-226Ra ages of crystals from the silicic endmember of the most recent Mt Hood eruptions both have average ages of >4.5 ka and likely have cores with ages >10 ka (Eppich et al., EPSL, 2012 v. 317-318). Diffusion of Sr in plagioclase limits the time spent at temperatures >850-900 °C to less than a few decades. Crystal sizes and CSDs constrain the total duration of crystal growth and allow identification of multiple crystal populations in the samples. Collectively, these data constrain models of crystal growth and dissolution as a function of thermal histories, showing that only a small fraction of the total time that the crystals were present could have been spent at temperatures significantly above the solidus, and an even smaller fraction of that time could have been spent at temperatures high enough for trace-element diffusion to be significant. These observations suggest that the state of the reservoir in which crystals at Mt Hood are stored was at near- or sub-solidus temperatures for most of its history, with brief excursions to higher temperature likely related to recharge and eruption (and which may have resulted in some dissolution of crystals). The U-series crystallization ages and modeled trace-element diffusion time scales at Mt Hood are similar to those measured in other volcanic systems, suggesting that these results apply to many (perhaps most) volcanic reservoir systems.

Cooper, K. M.; Kent, A. J.

2012-12-01

59

Rapid Climate Oscillations During the Last Deglaciation Synchronised by TIMS U-series Dating of a Stalagmite in East China  

NASA Astrophysics Data System (ADS)

Evidence for nearly synchronous climate oscillations during the last deglaciation has been found throughout the Northern Hemisphere but few records are based on independent time-scales of calendar years. We present the first U-series dated oxygen-carbon isotope record for a speleothem from Tangshan Cave, east China, which demonstrates unambiguously that abrupt deglacial climatic oscillations from 16,800 to 10,500 years BP are synchronous with those found in Greenland ice core records. Rapid shifts in speleothem \\delta18O, interpreted as reflecting changes in the amount of monsoon precipitation, demonstrate that the intensity of the East Asian monsoon switched within decades, in parallel with the abrupt transitions separating the B? lling-Aller? d (BA), Younger Dryas (YD), and pre-Boreal (PB) climatic reversals. \\delta13C values also change systematically, reflecting biomass response to changes in monsoon precipitation. The Tangshan record shows that the transitions to BA, YD and PB climatic conditions occurred at 14.62+/-0.10, 12.47+/-0.10 and 11.54+/-0.10 thousand years BP, respectively, which, considering different age errors, are in very good agreement with GRIP, GISP2 and Lake Gosciaz records. Our results suggest that the amount of monsoonal rainfall changes rapidly in parallel with deglacial temperature changes in the north Atlantic region, which is consistent with long-term histories of monsoon moisture documented using the loess, lake and marine sediment records in China. East Asian monsoon circulation is controlled by seasonal changes in the land-sea thermal gradient between the East Asian continent and the Pacific Ocean. During glacial (or stadial) periods, the winter monsoon strengthens as a result of intensified outflow of cold and dry air from the Siberian/Mongolian High, which was driven by westerly wind transport of cold air from the North Atlantic. In contrast, the summer monsoon weakens because of the reduced sea-land thermal gradient, coupled with reduced sea-surface temperature and moisture level above the western Pacific. During interglacial (or interstadial) periods, changes in the monsoon system tend to be the reverse. Thus changes in air temperature in the north Atlantic appear to be capable of reorganising the large-scale atmospheric circulation in the northern hemisphere with profound implications for monsoonal rainfall in East Asia. The Tangshan speleothem records provide the first unambiguous evidence for synchronised, abrupt climatic changes in the North Atlantic and East Asia regions. Such rapid hemispheric synchronicity strongly supports the role of atmospheric teleconnections in controlling global climate change during the last glaciation. The study shows that C-O isotope records extracted from climatically sensitive U-series-dated speleothems, like Devils Hole calcite vein, should play an important role in future investigations of the timing and duration of global climatic events.

Zhao, J.; Wang, Y.; Collerson, K. D.; Gagan, M. K.

2001-12-01

60

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

SciTech Connect

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.

Stein, M.; Wasserburg, G.J.; Chen, J.H. (California Inst. of Technology, Pasadena (United States)); Aharon, P. (Louisiana State Univ., Baton Rouge (United States)); Zhu, Z.R.; Chappell, J. (Australian National Univ., Canberra (Australia)); Bloom, A. (Cornell Univ., Ithaca, NY (United States))

1993-06-01

61

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

NASA Astrophysics Data System (ADS)

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.

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

2002-05-01

62

Transport and exchange of U-series nuclides between suspended material, dissolved load and colloids in rivers draining basaltic terrains  

NASA Astrophysics Data System (ADS)

This study presents uranium and thorium concentrations and activity ratios for all riverine phases (bedload, suspended load, dissolved load and colloids) from basaltic terrains in Iceland and the Azores. Small basaltic islands, such as these, are thought to account for ~ 25% of CO 2 consumed by global silicate weathering, and for ~ 45% of the flux of suspended material to the oceans. These data indicate that [U] and [Th] in the dissolved and colloidal fractions are strongly controlled by pH, and to a much lesser extent by levels of dissolved organic carbon (which are low in these environments). At high pH, basalt glass dissolution is enhanced, and secondary mineral formation (e.g. Fe-oxyhydroxides and allophane) is suppressed, resulting in high dissolved [U], and low colloidal [U] and [Th], indicating a direct chemical weathering control on elemental abundances. When the dissolved ( 234U/ 238U) activity ratio is >~1.3 (i.e. when physical weathering, groundwater contribution or soil formation are high), there is little isotope exchange between dissolved and colloidal fractions. At lower activity ratios, the dissolved load and colloids have indistinguishable activity ratios, suggesting that when chemical weathering rates are high, secondary clay formation is also high, and colloids rapidly adsorb dissolved U. Many of the suspended sediment samples have ( 234U/ 238U) activity ratios of > 1, which suggests that uptake of U onto the suspended load is important. Identical ( 230Th/ 232Th) in suspended, dissolved and colloidal samples suggests that Th, like U, is exchanged or sorbed rapidly between all riverine phases. This particle-reactivity, combined with poorly constrained contributions from groundwater and hydrothermal water, and short-term variations in input to soils (volcanic and glacial), suggests that U-series nuclides in riverine material from such basaltic terrains are unlikely to reflect steady state erosion processes.

Pogge von Strandmann, Philip A. E.; Burton, Kevin W.; Porcelli, Don; James, Rachael H.; van Calsteren, Peter; Gislason, Sigurður R.

2011-01-01

63

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

NASA Astrophysics Data System (ADS)

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.

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

2010-12-01

64

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

65

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)

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.

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

2013-12-01

66

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

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.

Chakraborty, R.; Zhong, Y.; Andrade, M. de [Univ. of Texas Graduate School of Biomedical Sciences, Houston, TX (United States)] [and others] [Univ. of Texas Graduate School of Biomedical Sciences, Houston, TX (United States); and others

1994-06-01

67

Precise geochronology of phoscorites and carbonatites: - The critical role of U-series disequilibrium in age interpretations  

NASA Astrophysics Data System (ADS)

We present the results of a comparative study of several geochronometer minerals (baddeleyite, zircon, apatite, phlogopite and tetraferriphlogopite) and isotopic systems (U-Pb, Th-Pb and Rb-Sr) from phoscorites (magnetite-forsterite-apatite-calcite rocks) and carbonatites of the Kovdor ultramafic-alkaline-carbonatite massif, Kola Peninsula, Russia. Uranium, thorium and their decay products are extremely fractionated by minerals that crystallise from carbonatite and phoscorite magma. We obtain high-precision ages from different chronometers, compare their accuracy, and evaluate the role of geochronological pitfalls of initial radioactive disequilibrium, differential migration of radiogenic isotopes, and inaccurate decay constants. Apatite yielded concordant U-Th-Pb ages between 376 and 380 Ma. The accuracy of the apatite 238U- 206Pb ages is, however, compromised by uncertainty in the amount of radiogenic 206Pb produced from initial excess 230Th. The 235U- 207Pb ages are relatively imprecise due to large common Pb correction and the uncertainty in the initial Pb isotopic composition. The Th-Pb system yields a more precise age of 376.4 ± 0.6 Ma. Zircon from two carbonatite samples is characterised by moderate to low U contents, high Th contents, and very high Th/U ratios up to 9000. The 206Pb*/ 238U systems in the zircon are strongly affected by the presence of excess 206Pb*, produced by decay of initial 230Th. The 208Pb*/ 232Th ages of zircon from both carbonatite samples are uniform and yield a weighted average of 377.52 ± 0.94 Ma. Baddeleyite U-Pb analyses are 3 to 6% normally discordant and have variable 207Pb*/ 206Pb* apparent ages. Eleven alteration-free baddeleyite fractions from three samples with no evidence for Pb loss yield uniform 206Pb*/ 238U ages with a weighted average of 378.54±0.23 Ma (378.64 Ma after correction for initial 230Th deficiency), which we consider the best estimate for age of the phoscorite-carbonatite body of the Kovdor massif. The 206Pb*/ 238U ages of baddeleyite fractions from five other samples spread between 378.5 and 373 Ma, indicating a variable lead loss up to 1.5%. The anomalously old 207Pb/ 235U and 207Pb/ 206Pb ages are consistent with the presence of excess radiogenic 207Pb* in the baddeleyite. We interpret this as a result of preferential partitioning of 231Pa to baddeleyite. Fifteen phlogopite and tetraferriphlogopite fractions from five carbonatite and phoscorite samples yielded precise Rb-Sr isochron age of 372.2 ± 1.5 Ma, which is 5 to 7 m.y. younger than our best estimate based on U-Th-Pb age values. This difference is unlikely to be a result of the disturbance or late closure of Rb-Sr system in phlogopite, but rather suggests that the accepted decay constant of 87Rb is too high. Comparative study of multiple geochronometer minerals from the Kovdor massif has revealed an exceptional complexity of isotopic systems. Reliable ages can be understood through systematic analysis of possible sources of distortion. No single geochronometer is sufficiently reliable in these rocks. Th-Pb and Rb-Sr can be a very useful supplement to U-Pb geochronometry, but the routine use of these geochronometers together will require more precise and accurate determination of decay constants for 232Th and 87Rb.

Amelin, Yuri; Zaitsev, Anatoly N.

2002-07-01

68

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)

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 15.7±0.1 to 36.9±0.1kyrs. 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 (2.1±0.2 to 21±0.1kyrs) are observed at the Alfalfa site. These ages generally decrease with increasing depth with the youngest carbonate ages (2.1±0.2 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.

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

2012-12-01

69

Enhancing in-situ U-series accessory mineral chronometry to constrain pace and processes of magma accumulation, storage, and eruption  

NASA Astrophysics Data System (ADS)

Over the past decade, deciphering absolute crystallization ages at micro-scales through in-situ U-series dating has spearheaded conceptual changes in the understanding of how magmas evolve en route to the surface. U-Th and U-Pb zircon geochronology by secondary ionization mass spectrometry (SIMS) now routinely accesses a continuous age spectrum extending well into the Holocene with ka precision for individual analysis spots ~25 - 40 ?m in diameter. SIMS depth profiling further increases spatial resolution at least tenfold. These developments are epitomized by studies that document multiple generations of zircon growth, predating eruptions by 10's to 100's of ka, as common features in silicic volcanics. Recently, these methods have been enhanced by (1) linking ages to Ti-in-zircon thermometry and trace element or oxygen isotopic fingerprinting; (2) tracking compositional changes with age in accessory minerals sensitive to magma differentiation, such as allanite; and (3) combining U-Th zircon ages with other chronometers, such as (U-Th)/He zircon or 226Ra-230Th-238U plagioclase dating. The emerging picture reveals a wide gamut of processes acting in magma bodies, including piecemeal, compartmentalized magma aggregation, protracted and thermally retrograde crystal storage coupled with magma differentiation, thermal rejuvenation and recycling of crystal mushes and solidified intrusions or magma chamber rinds, and wall rock assimilation. For the future, experimental constraints on accessory mineral-melt partitioning (e.g., Ayers and Luo, 2008: Geochim Cosmochim Acta, v. 72, p. A39) promise to put interpretation of zircon compositions on firmer footing, as is the case for additional accessory mineral saturation calibrations and improved modeling of existing ones (e.g., Harrison et al., 2007: Geology, v. 35, p. 635-638). By the same token, new experimental constraints on U-series element partitioning (e.g., Miller et al., 2007: Am Min, v. 92, p. 1535-1538) should enhance precision and applicability of mineral chronometers. Moreover, analytical advances in high spatial resolution SIMS hold promise for utilizing melt inclusions in zircon as an additional repository for constraining the chemical and thermal evolution of magmas.

Schmitt, A. K.

2008-12-01

70

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

NASA Astrophysics Data System (ADS)

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.

Grün, Rainer; Aubert, Maxime; Joannes-Boyau, Renaud; Moncel, Marie-Hélène

2008-11-01

71

Properties of Natural Radiation and Radioactivity  

SciTech Connect

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."

Strom, Daniel J.

2009-07-13

72

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)

The Icelandic central volcano of Krafla exhibits increasing assimilation of hydrothermally-altered crust with increasing differentiation of magmas, as evidenced by decreasing ?18O 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 ?18O 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 ?18O 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 ?18O of plagioclase suggests that the plagioclase source had assimilated more low-?18O crustal material than the host magmas. However, ?18O 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.

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

2008-12-01

73

Radiogenic and U-series isotopes in very low sedimentation rate sediments from Mendeleev Ridge (Arctic Ocean): sources, mineral carriers and stratigraphic implications  

NASA Astrophysics Data System (ADS)

Sedimentological and geochemical properties, U-series isotopes, radiogenic isotopes and anthropogenic radionuclides contents were determined on two cores from the Mendeleev Ridge. Excesses in 210Pb over 226Ra activities are observed down to 1.25 cm from core-tops, due to shallow mixing by benthic organisms. Below, 210Pb-activity follows 226Ra-activity in turn controlled by parent 230Th-excess fluctuations in the sediment, except for some 226Ra-diffusion towards the water column from core-top and on both sides of 230Thxs peaks below. Thus, estimating 210Pb-excess requires precise knowledge of 226Ra-supported fraction, i.e., of 230Th- excess and Ra-diffusion. Both cores depict identical grain size, mineralogical, geochemical and isotopic distributions, despite bathymetric difference. This suggests negligible impact of bottom currents, limited scavenging of heavy metals in the lower water column, and a net export of particle reactive U-daughter isotopes (Th, Pa, Pb) produced from the overlying water column. Peaks in 230Thxs and 231Paxs (0-7cm, 17 cm and 30 cm sub-bottom) match high contents in clays and fine carbonates (primarily dolomite), and likely indicate interglacial/interstadial conditions and/or occurrence of turbidity events (e.g., during deglaciations). These peaks correspond to maximum illite supplies, minimum Sr-isotope ratios and epsilon-Nd values in the -10 to -12 range. Interlayered sediments, with high sand but low carbonate contents, minimum clay fluxes (low illite relative contents), minimum 230Th and 231Pa excesses, maximum Sr-isotope ratios, possibly indicate full glacial conditions and significantly reduced sedimentation rates.

Hillaire-Marcel, C.; Darby, D.; Francois, R.; Helie, J.; Lamziouaq, R.; Not, C.; Polyak, L.; Preda, M.; Satte, Y. M.; Stevenson, R.

2007-12-01

74

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

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 80–90% closed-system crystal fractionation over a temperature interval from 1279°C to 719°C 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 50–200 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.

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

2010-01-01

75

Radioactive Decay  

NSDL National Science Digital Library

With knowledge of Maple, Mathmatica, or MatLab, one should be able to develop a mathematical model for decay of radioactive substances and develop a technique for deciding whether quantitative data fits the model or not.

Smith, David

2001-01-22

76

Radioactive Iodine  

MedlinePLUS

... form of iodide, is made into two radioactive isotopes that are commonly used in patients with thyroid ... the best results? I-123 is the usual isotope used to take pictures and determine the activity ...

77

Radioactive wastes  

SciTech Connect

This paper briefly reviews current literature regarding management of radioactive wastes including: national programs; waste repositories; mixed wastes; decontamination and decommissioning; remedial actions and treatment; and, environmental occurrence and transport of radionuclides. 193 refs.

Devarakonda, M.S.; Seiler, M.C. [IT Corp., Albuquerque, NM (United States)

1995-06-01

78

Simulated Radioactivity  

ERIC Educational Resources Information Center

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)

Boettler, James L.

1972-01-01

79

Concentrating Radioactivity  

ERIC Educational Resources Information Center

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)

Herrmann, Richard A.

1974-01-01

80

Radioactivity Calculations  

ERIC Educational Resources Information Center

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)

Onega, Ronald J.

1969-01-01

81

Handling radioactivity  

SciTech Connect

The aim of this book is to present an overall view in a descriptive and essentially nonmathematical way of the practicalities of handling radioactivity. It is hoped that the material will be particularly helpful to those entering the nuclear field for the first time and to those working in related areas whose responsibilities require them to have a general knowledge of the subject of radioactivity handling and its vocabulary.

Stewart, D.C.

1988-01-01

82

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)

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.

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

2000-09-01

83

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

Microsoft Academic Search

238U and 232Th concentrations and the extent of 238U-234U-230Th 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

S. K. Singh; Tarun K. Dalai; S. Krishnaswami

2003-01-01

84

Radioactive wastes  

SciTech Connect

This paper reviews research and technological progress in radioactive waste management and disposal. The scope of material covered is very broad, ranging from international cooperation in radioactive waste management to evaluation of specific treatment technologies. The issue of safely managing and disposing of the plutonium resulting from the dismantling of weapons across the world is discussed and a series of papers on low-level waste management practices across the world is mentioned. Environmental restoration, risk assessment, and the health hazards of radon are also discussed.

Devarakonda, M.S. [International Technology Corp., Albuquerque, NM (United States)

1993-06-01

85

Radioactive Wastes  

NSDL National Science Digital Library

Using Mathcad, Maple, Mathmatica, or MatLab, the user should be able to develop multiple representations for decay of radioactive substances, in the context of environmental policies on a university campus, and to determine storage times for wastes to decay to safe levels for disposal.

Smith, David

2001-01-22

86

Radioactive Wastes  

NSDL National Science Digital Library

Created by David Smith for the Connected Curriculum Project, this module develops multiple representations for decay of radioactive substances, in the context of environmental policies on a university campus, and discusses storage times for wastes to decay to safe levels for disposal. This is one of a much larger set of learning modules hosted by Duke University.

Smith, David

2010-04-29

87

Radioactive Decay  

NSDL National Science Digital Library

Created by William Barker and David Smith for the Connected Curriculum Project, the purposes of this module are to develop a mathematical model for decay of radioactive substances, and to develop a technique for deciding whether quantitative data fits the model or not. This is one lesson within a larger set of learning modules hosted by Duke University.

Barker, William; Smith, David

2010-07-05

88

Radioactive Decay  

NSDL National Science Digital Library

Created by William Barker and David Smith for the Connected Curriculum Project, this module develops a mathematical model for decay of radioactive substances, and a technique for deciding whether quantitative data fits the model or not. This is one within a much larger set of learning modules hosted by Duke University.

Barker, William; Smith, David

2010-06-28

89

Radioactive wastes  

SciTech Connect

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.

Devarakonda, M.S.; Hickox, J.A. [IT Corporation, Albuquerque, NM (United States)

1996-11-01

90

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

NASA Astrophysics Data System (ADS)

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.

Paces, James B.; Neymark, Leonid A.; Wooden, Joseph L.; Persing, Harold M.

2004-04-01

91

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

USGS Publications Warehouse

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.

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

2004-01-01

92

Radioactive Wastes  

NSDL National Science Digital Library

Created by Lang Moore and David Smith for the Connected Curriculum Project, the purposes of this module are to develop multiple representations for decay of radioactive substances, in the context of environmental policies on a university campus, and to determine storage times for wastes to decay to safe levels for disposal. This is one lesson within a larger set of learning modules hosted by Duke University.

Moore, Lang; Smith, David

2010-07-06

93

Radioactive wastes  

SciTech Connect

This paper is part of the Annual Literature Review issue of Water Environment Research. The review attempts to provide a concise summary of important water-related environmental science and engineering literature of the past year, of which 40 separate topics are discussed. On the topic of radioactive wastes, the present paper deals with the following aspects: national programs; waste repositories; mixed wastes; waste processing and decommissioning; environmental occurrence and transport of radionuclides; and remedial actions and treatment. 178 refs.

Devarakonda, M.S.; Melvin, J.M. (IT Corporation, Albuquerque, NM (United States))

1994-06-01

94

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

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

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

2003-01-01

95

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

NASA Astrophysics Data System (ADS)

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.

Condomines, Michel; Sigmarsson, Olgeir

1993-09-01

96

Estimation of heat generation by radioactive decay of some phosphate rocks in Egypt.  

PubMed

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

Din, Khaled Salahel

2009-11-01

97

Radioactive Waste Management.  

National Technical Information Service (NTIS)

Management of radioactive wastes is necessary to protect public health, public safety, and the environment from radioactive materials resulting from national defense programs, energy research and development, and commercial activities. Access to informati...

1988-01-01

98

Radioactivity and geophysics.  

National Technical Information Service (NTIS)

The paper recalls a few steps of the introduction of radioactivity in geophysics and astrophysics: contribution of radioelements to energy balance of the Earth, age of the Earth based on radioactive disintegration and the discovery of cosmic radiations. (...

P. Radvanyi

1992-01-01

99

Radioactive Waste Management.  

National Technical Information Service (NTIS)

Management of radioactive wastes is necessary to protect public health, public safety, and the environment from radioactive materials resulting from national defense programs, energy research and development, and commercial activities. Access to informati...

1990-01-01

100

Procedures for radioactive I-131  

SciTech Connect

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.

Sharma, S.C. (Univ. of Louisville, KY (USA))

1988-12-01

101

A study of environmental radioactivity measurements for Cankiri, Turkey.  

PubMed

This study is the first to assess the level of background radiation for the Cankiri province of Turkey. Indoor air radon concentrations were determined using Columbia Resin-39 nuclear track detectors and the average (222)Rn activity was found to be 44 Bq m(-3) (equivalent to an annual effective dose of 1.1 mSv). Measurements of gamma doses in outdoor air were performed using a portable plastic scintillation detector and the average gamma absorbed dose rate was found to be 8 ?R h(-1) (corresponding to an annual effective dose of 87.7 ?Sv). Radionuclide activity concentrations in soil samples were measured through gamma-ray spectrometry and the average activities were determined as 17.7, 22.3, 357 and 4.1 Bq kg(-1) for the radionuclides (238)U, (232)Th, (40)K and (137)Cs, respectively. The average annual effective dose from the natural radioactivity sources ((238)U series, (232)Th series and (40)K) was calculated to be 44.4 ?Sv. Radioactivity levels of drinking water samples were carried out using a low-background proportional counter and the average gross alpha and beta activities were obtained as 0.25 and 0.26 Bq l(-1), respectively (equivalent to an annual effective dose of 184 ?Sv). The average radon concentrations in indoor air and the average radionuclide activities in soil were found to be lower than most Turkish cities while higher levels of outdoor gamma dose rate and water radioactivity were observed. The results of this study showed that the region's background radioactivity level differs considerably from the reported data for Turkish cities. PMID:22069234

Kapdan, Enis; Taskin, Halim; Kam, Erol; Osmanlioglu, A Erdal; Karahan, Gursel; Bozkurt, Ahmet

2012-07-01

102

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

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.

Cooper, Kari M.; Donnelly, Carrie T.

2008-01-01

103

Radioactive Waste Management Basis  

SciTech Connect

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.

Perkins, B K

2009-06-03

104

Temporary Personal Radioactivity  

NASA Astrophysics Data System (ADS)

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.

Myers, Fred

2012-11-01

105

Radioactivity by the whiff  

Microsoft Academic Search

Four important areas in science and industry make use of radioactive gas mixtures: tracing, electronics, leak detection, and research. Oil and natural gas producing companies have instituted the use of radioactive gas mixtures in a technique called radiographic well logging. In this process, specific radiogas mixtures are injected into a known oil field. After the gas has been diluted through

M. S. Stocknoff; F. Scornavacca

1974-01-01

106

Radioactive Wastes. Revised.  

ERIC Educational Resources Information Center

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…

Fox, Charles H.

107

A Remote Radioactivity Experiment  

ERIC Educational Resources Information Center

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…

Jona, Kemi; Vondracek, Mark

2013-01-01

108

Radioactive Dating Methods  

NASA Astrophysics Data System (ADS)

This chapter provides a necessarily brief summary of radioactive dating techniques, which can produce dates (“ages”) ranging from tens to thousands through millions to billions of years often with assumptions not universally accepted, especially those involving the assessments of half-lives and radioactive decay constants.

Bowen, R.

109

Temporary Personal Radioactivity  

ERIC Educational Resources Information Center

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…

Myers, Fred

2012-01-01

110

Radioactive Decay Model  

NSDL National Science Digital Library

The EJS Radioactive Decay Model simulates the decay of a radioactive sample using discrete random events. It displays the number of radioactive nuclei as a function of time. You can change the initial number of nuclei and the decay constant as well as changing the plot to a semi-log plot. The Radioactive Decay model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ms_explicit_RadioactiveDecay.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2009-01-23

111

A Remote Radioactivity Experiment  

NASA Astrophysics Data System (ADS)

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 of us (MV) worked at, and after talking with numerous colleagues we know this is still the case at many schools. What options are there then for physics teachers to allow their students to experimentally investigate certain characteristics of radioactivity, such as how distance affects the intensity of radiation coming from a radioactive source? There are computer simulations that can be run, or perhaps the teacher has a light sensor and tries to make an analogy between the intensity of light from a light bulb and the intensity of radiation from a radioactive source based on geometric arguments to get an inverse-square law. But for many there is no direct experimental option if one does not possess a Geiger counter and good radioactive sample. It is for that teacher and class of students that an online, remote radioactivity experiment was created.

Jona, Kemi; Vondracek, Mark

2013-01-01

112

Table of Radioactive Isotopes.  

National Technical Information Service (NTIS)

A description is given for the Table of Radioactive Isotopes which will be published in 1986. The format of the table is given as to content and organization. 22 refs., 2 figs. (ERA citation 11:010444)

R. B. Firestone E. Browne

1985-01-01

113

Radioactive Material Regulations Review.  

National Technical Information Service (NTIS)

This review provides guidance on the DOT Hazardous Materials Regulations contained in Title 49, Code of Federal Regulations (HMR; 49 CFR) which govern the packaging and shipment of radioactive material. These materials have an excellent safety record when...

2012-01-01

114

Radioactivity of Vegetable Crops.  

National Technical Information Service (NTIS)

Potatoes, carrots, onions, turnips, and radishes grown in several areas of the Samarkand Oblast were studied to ascertain their natural radioactivity. Results of beta and gamma measurements are presented. (ERA citation 07:063511)

M. M. Muminov U. Maksudov

1967-01-01

115

Radioactive Waste Material Incinerator.  

National Technical Information Service (NTIS)

The incinerator is for the disposal of combustible radioactive waste material. The structure prevents the release of hazardous amounts of radionuclides into the environment. The structure includes a closed system silo-type combustion chamber for the mass ...

C. F. Berghout M. Dauer F. W. Lanard R. P. Minx W. E. Senoski

1965-01-01

116

Understanding radioactive waste  

SciTech Connect

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)

Murray, R.L.

1981-12-01

117

Incineration of Radioactive Waste.  

National Technical Information Service (NTIS)

In this study, made on contract for the Swedish Nuclear Power Inspectorate, different methods for incineration of radioactive wastes are reviewed. Operation experiences and methods under development are also discussed. The aim of incineration of radioacti...

C. Thegerstroem

1980-01-01

118

Container for radioactive materials  

DOEpatents

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.

Fields, Stanley R. (Richland, WA)

1985-01-01

119

Dynamic radioactive particle source  

DOEpatents

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.

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

2012-06-26

120

Radioactive Decay Distribution Model  

NSDL National Science Digital Library

The EJS Radioactive Decay Distribution Model simulates the decay of a radioactive sample using discrete random events. It displays the distribution of the number of events (radioactive decays) in a fixed time interval. If each event is assumed to occur independently and spontaneously with a constant probability, the resulting distribution if the Poisson distribution. You can change the initial number of nuclei, the decay constant and the time interval for the event distribution. The Radioactive Decay Distribution model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ms_explicit_RadioactiveDecayDistribution.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2009-01-23

121

Radioactivity in food crops  

SciTech Connect

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.

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

1983-05-01

122

Radioactivity of Consumer Products  

NASA Astrophysics Data System (ADS)

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.

Peterson, David; Jokisch, Derek; Fulmer, Philip

2006-11-01

123

Trapping radioactive ions  

NASA Astrophysics Data System (ADS)

Trapping devices for atomic and nuclear physics experiments with radioactive ions are becoming more and more important at accelerator facilities. While about ten years ago only one online Penning trap experiment existed, namely ISOLTRAP at ISOLDE/CERN, meanwhile almost every radioactive beam facility has installed or plans an ion trap setup. This article gives an overview on ion traps in the operation, construction or planing phase which will be used for fundamental studies with short-lived radioactive nuclides such as mass spectrometry, laser spectroscopy and nuclear decay spectroscopy. In addition, this article summarizes the use of gas cells and radiofrequency quadrupole (Paul) traps at different facilities as a versatile tool for ion beam manipulation like retardation, cooling, bunching, and cleaning.

Kluge, H.-J.; Blaum, K.

2004-12-01

124

Container for radioactive materials  

DOEpatents

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.

Fields, S.R.

1984-05-30

125

TABLE OF RADIOACTIVE ELEMENTS.  

SciTech Connect

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.

HOLDEN,N.E.

2001-06-29

126

Sampling airborne radioactivity  

SciTech Connect

Radioactive contaminants have historically been considered apart from chemical contaminants because it is their radiological properties that determine their biological and environmental impact. Additionally they have been regulated by special government agencies concerned with radiological protection. Radioactive contaminants are also distinguished by the specialized and very sensitive methods available for the detection of radioactivity. Measurements of a few thousand atoms per liter are not uncommon. Radiation detectors in common use are gas filled chambers, scintillation and semiconductor detectors, and the more recently developed thermoluminescent and etched track detectors. Solid-state nuclear track detectors consist of a large group of inorganic and organic dielectrics which register tracks when traversed by heavy charged particles. They do not respond to light, beta particles or gamma ray photons and thus provide a very low background system for the detection of extremely low levels of radioactivity. In addition, no power source or electronic equipment is required. Cellulose nitrate detectors are currently in use for long term integrated sampling of environmental radon. Thermoluminescent dosimeters (TID's) are crystalline materials, in which electrons which have been displaced by an interaction with ionizing radiation become trapped at an elevated energy level and emit visible light when released from that energy level. As which etched-track detectors no power or electronic equipment is needed for the TID's at a measurement site, but they respond to alpha, beta and gamma radiation. Thermoluminescent dosimeters are useful for long term environmental monitoring, and have also been newly incorporated into integrating radon detection systems.

Cohen, B.S.

1988-01-01

127

Disposal of radioactive waste  

NASA Astrophysics Data System (ADS)

The aim of radioactive and non-radioactive waste management is to protect man and the environment from unacceptable risks. Protection criteria for both should therefore be based on similar considerations. From overall protection criteria, performance criteria for subsystems in waste management can be derived, for example for waste disposal. International developments in this field are summarized. A brief overview of radioactive waste sorts and disposal concepts is given. Currently being implemented are trench disposal and engineered near-surface facilities for low-level wastes. For low-and intermediate-level waste underground facilities are under construction. For high-level waste site selection and investigation is being carried out in several countries. In all countries with nuclear programmes, the predicted performance of waste disposal systems is being assessed in scenario and consequence analyses. The influences of variability and uncertainty of parameter values are increasingly being treated by probabilistic methods. Results of selected performance assessments show that radioactive waste disposal sites can be found and suitable repositories can be designed so that defined radioprotection limits are not exceeded.

Van Dorp, Frits; Grogan, Helen; McCombie, Charles

128

Table of radioactive isotopes  

Microsoft Academic Search

This book provides a comprehensive and critical evaluation of the nuclear and atomic properties of radioactive isotopes. Detailed radiation data for about 2000 of the 2755 known nuclides are presented in this up-to-date and concise book. The main section is organized by mass number (A), with entries for a given A derived from and referenced to the most recent corresponding

Edgardo Browne; Richard B. Firestone; V. S. Shirley

1986-01-01

129

Vacuuming radioactive sludge  

SciTech Connect

Vacuuming an estimated 55 cubic yards of radioactive sludge from the floor of Hanford's K East Basin was a complicated process. Workers stood on grates suspended above the 20-foot deep basin and manipulated vacuuming equipment at the end of long poles--using underwater cameras to guide their work.

2006-10-16

130

Radii of radioactive nuclei.  

National Technical Information Service (NTIS)

A new simple direct method for the measurement of the total reaction cross section ((sigma)(sub R)) for several light radioactive nuclei (A(le)40) is developed. From that, the reduced strong absorption radii (r(sub o)(sup 2)) are obtained. A comparison is...

W. Mittig E. Plagnol Y. Schutz

1989-01-01

131

Material for radioactive protection  

Microsoft Academic Search

A boron containing burn resistant, low-level radiation protection material useful, for example, as a liner for radioactive waste disposal and storage, a component for neutron absorber, and a shield for a neutron source is described. The material is basically composed of borax in the range of 25 to 50%, coal tar in the range of 25 to 37.5%, with the

R. S. Taylor; N. W. Boyer

2009-01-01

132

PERSONNEL RADIOACTIVITY MONITOR  

Microsoft Academic Search

An apparatus is described which measures radioactive contamination on ; hands, shoes, and clothes. It consists of two photomultipliers with ZnS screens ; for alpha contamination of the hands, six Geiger counters to detect beta ; radiation from the shoes, and one probe for monitoring the clothes. The ; instrument is completely transistorized and automatic. Each measurement lasts 10 ;

Mandl

1959-01-01

133

Radioactivity: A Natural Phenomenon.  

ERIC Educational Resources Information Center

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)

Ronneau, C.

1990-01-01

134

Viewer Makes Radioactivity "Visible"  

NASA Technical Reports Server (NTRS)

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.

Yin, L. I.

1983-01-01

135

DISPOSAL OF RADIOACTIVE WASTES  

Microsoft Academic Search

The amount of radioactive wastes from isotope users in the Federai ; Republic of Germany is rather small. Adequate provisions of the First Radiation ; Protection Ordinance deal with the waste disposal by the deposition into soil or ; ordinary wastes, and the discharge into sewers or surface waters. (auth) O H7655 ; Research progress is reported on biologicai and

Straimer

1962-01-01

136

Radioactive I-131 from Fallout  

MedlinePLUS

Radioactive I-131 from Fallout Page Options Print This Page Email This Document Share Popular Resources NCI Dictionary of ... Search for Clinical Trials NCI Publications Español Radioactive I-131 from Fallout Information and resources for Americans ...

137

Environmental Radioactivity, Temperature, and Precipitation.  

ERIC Educational Resources Information Center

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)

Riland, Carson A.

1996-01-01

138

THE HANDLING OF RADIOACTIVE MATERIALS  

Microsoft Academic Search

The fundamentals and the dangers inherent in handling radioactive ; materials are discussed, making particular reference to reactor coolants (gas, ; water, and liquid metals). The danger inherent in handling radioactive ma ; terials lies in the electromagnetic radiation produced when atomic particles ; collide or interact with various substances. Precautions and methods of ; protection from radioactive materials are

Hadrill; H. F. J

1961-01-01

139

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

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.

Owen, L. A.; Bright, J.; 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

140

Radioactive ion detector  

DOEpatents

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.

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

1997-01-01

141

Radioactive ion detector  

DOEpatents

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.

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

1997-08-12

142

Table of radioactive elements  

SciTech Connect

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.

Holden, N.E.

1985-01-01

143

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

SciTech Connect

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.

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

2003-02-27

144

PERSPECTIVE: Fireworks and radioactivity  

NASA Astrophysics Data System (ADS)

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

Breitenecker, Katharina

2009-09-01

145

Radioactive waste material disposal  

DOEpatents

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.

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

1995-10-24

146

Radioactive waste material disposal  

DOEpatents

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.

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

147

Radioactive Decay of Candium  

NSDL National Science Digital Library

In this simulation, learners use M&M⢠candy to explore radioactive isotope decay. Learners pour out a bag of candy and count and record the number of candy pieces that have "decayed" or show the print side up. Learners get to consume the "decayed atoms." Then, they will shake the bag again and recount the decay. Learners will continue shaking, counting and consuming until all the atoms have decayed, and then graph the results. This activity is a great introduction to half-life and nuclear decay.

House, The S.

2014-01-28

148

Natural radioactivity in water supplies  

SciTech Connect

This book outlines the scientific aspects of the control of natural radioactivity in water supplies, as well as the labyrinthine uncertainties in water quality regulation concerning natural radiocontamination of water. The author provides an introduction to the theory of natural radioactivity; addresses risk assessment, sources of natural radiocontamination of water, radiobiology of natural radioactivity in water, and federal water law concerning natural radiocontamination; and presents an account of how one city dealt with the perplexities that mark this area of water quality regulation.

Horner, J.K.

1985-01-01

149

Radioactive waste processing apparatus  

DOEpatents

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.

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

1987-01-01

150

Regulations on radioactive waste from practices using unsealed radioactive sources  

Microsoft Academic Search

Regulations on handling and disposal of waste from non-nuclear facilities have been in force in Sweden since 1985. These regulations are applicable on the handling of solid and liquid wastes from laboratories covered with licenses granted by the Radiation Protection Authority, SSI, for work with radioactive substances and where work results in production of radioactive wastes. Patient excreta is exempted

Ann-Louis Söderman; Gunilla Hellström

151

RADIOACTIVE MATERIALS AND INDUSTRIAL FIRE PROTECTION  

Microsoft Academic Search

Information is presented en the development of safe pnactices for fire ; protection and fire prevention where radioactive materials might be involved. ; Discussions are inclued on: hazards of radioactive materials and regulations for ; the application of radioactive materials, the increasing use of radioactive ; materials in industry, the behavior of radioactive materials exposed to high ; temperatures or

1958-01-01

152

Design of saltstone vaults. [Radioactive  

Microsoft Academic Search

Radioactive wastes from processed spent nuclear fuel at the Savannah River Plant, South Carolina, are stored in underground tanks. The wastes consist of sludge and supernate. Most of the radionuclides and some non-radioactive constituents are removed from the supernate. These, along with the sludge, are converted into a glass-crystallite matrix and cast into stainless steel canisters for future disposal in

G. S. Aiyar; F. J. Hsiu

1987-01-01

153

Radioactive waste backup threatens research  

Microsoft Academic Search

Problems in the disposal of low-level radioactive wastes are discussed. Due to the closing of the disposal site at Hanford, Washington, radioactive wastes from medical research at various universities and medical centers around the country have begun to stockpile. The reason given for the closing is that the wastes had been carelessly packaged.

E Marshall

1979-01-01

154

Radioactive elements in stellar atmospheres  

SciTech Connect

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.

Gopka, Vira [Astronomical observatory, Odessa National University, Odessa (Ukraine); Yushchenko, Alexander [Astrophysical Research center for the Structure and Evolution of the Cosmos, Sejong University, Seoul (Korea, Republic of); Astronomical observatory, Odessa National University, Odessa (Ukraine); Goriely, Stephane [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, Brussels (Belgium); Shavrina, Angelina [Main Astronomical observatory, National Academy of Sciences of Ukraine, Kiev (Ukraine); Kang, Young Woon [Astrophysical Research center for the Structure and Evolution of the Cosmos, Sejong University, Seoul (Korea, Republic of)

2006-07-12

155

SEPARATION OF RADIOACTIVE COLUMBIUM TRACER  

Microsoft Academic Search

A process is presented for the recovery of radioactive columbium from ; solutions containing such columbium together with radioactive tellurium. The ; columbium and tellurium values are separated from such solutions by means of an ; inorganic oxide carrier precipitate, such as MnOâ. This oxide carrier ; precipitate and its associated columbium and telluriuan values are then dissolved ; in

L. E. Glendenin; H. Gest

1958-01-01

156

Heavy fragment radioactivities  

SciTech Connect

This recently discovered mode of radioactive decay, like alpha decay and spontaneous fission, is believed to involve tunneling through the deformation-energy barrier between a very heavy nucleus and two separated fragments the sum of whose masses is less than the mass of the parent nucleus. In all known cases the heavier of the two fragments is close to doubly magic /sup 208/Pb, and the lighter fragment has even Z. Four isotopes of Ra are known to emit /sup 14/C nuclei; several isotopes of U as well as /sup 230/Th and /sup 231/Pa emit Ne nuclei; and /sup 234/U exhibits four hadronic decay modes: alpha decay, spontaneous fission, Ne decay and Mg decay.

Price, P.B.

1987-12-10

157

Low Radioactivity in CANDLES  

SciTech Connect

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.

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. [Department of Physics, Osaka University, Toyonaka, Osaka, 560-0043 (Japan)

2005-09-08

158

Natural radioactivity in water supplies  

SciTech Connect

This book outlines the scientific aspects of the control of natural radioactivity in water supplies, as well as the labyrinthine uncertainties in water quality regulation concerning natural radiocontamination of water. The author provides an introduction to the theory of natural radioactivity; addresses risk assessment, sources of natural radiocontamination of water, radiobiology of natural radioactivity in water, and federal water law concerning natural radiocontamination. It presents an account of how one city dealt with the perplexes that mark the rapidly evolving area of water quality regulation. The contents include: radioactivity and risk; an introduction to the atomic theory; an introduction to natural radioactivity; risk assessment; uranium and radium contamination of water; radiobiology of uranium and radium in water. Determination of risk from exposure to uranium and radium in water; the legal milieu; one city's experience; and summary: the determinants of evolving regulation.

Horner, J.K.

1985-01-01

159

Star formation and extinct radioactivities  

NASA Technical Reports Server (NTRS)

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.

Cameron, A. G. W.

1984-01-01

160

U-Series dating of Dead Sea Basin carbonates  

Microsoft Academic Search

An attempt is made to apply the Th 230 \\/ U 234 dating method to inorganic marls which are presumably associated with pluviation in the Jordan River-Dead Sea graben. The resulting ages seem to be acceptable with respect to their Th 230 -U 234 relationships, their internal stratigraphic consistency and their agreement with available C-14 ages. However, other evidence on

Aaron Kaufman

1971-01-01

161

Microbiological treatment of radioactive wastes.  

National Technical Information Service (NTIS)

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 remov...

A. J. Francis

1992-01-01

162

Radioactive Iodine Treatment for Hyperthyroidism  

MedlinePLUS

... for Hyperthyroidism Share: Fact Sheet Radioactive Iodine for Hyperthyroidism April, 2012 Download PDFs English Zulu Espanol Editors ... V. Hennessey, MD Leonard Wartofsky, MD What is hyperthyroidism? The thyroid gland, located at the front of ...

163

Radioactivity connected with coal burning.  

PubMed

The enhanced environmental radioactivity resulting from the operation of a 72 MWe brown coal-fired power plant in central Italy is considered. A source-related control procedure is suggested. The calculated values for the atmospheric dispersion of radioactive effluents and the results of some measurements on brown coals, ash, environmental samples and gamma-exposure levels performed at representative points are reported. PMID:4081758

Borio, R; Campos Venuti, G; Risica, S; Simula, S

1985-10-01

164

Storage depot for radioactive material  

DOEpatents

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.

Szulinski, Milton J. (Richland, WA)

1983-01-01

165

Disposal of low-level radioactive wastes  

Microsoft Academic Search

The generation of low-level radioactive waste is a natural consequence of the societal uses of radioactive materials. These uses include the application of radioactive materials to the diagnosis and treatment of human disease and to research into the causes of human disease and their prevention. Currently, low level radioactive wastes are disposed of in one of three shallow land-burial disposal

W HENDEE

1986-01-01

166

Distribution of low-level natural radioactivity in a populated marine region of the Eastern Mediterranean Sea.  

PubMed

The levels of natural radioactivity have been evaluated in the water column of an eastern Mediterranean region (Saronikos Gulf), with respect to the relevant environmental parameters. A novel methodology was used for the determination of natural radionuclides, which substitutes the time-consuming radiochemical analysis, based on an in situ sample preconcentration using ion-selective manganese fibres placed on pumping systems. With regard to the results obtained, (238)U-series radionuclides were found at the same level or lower than those observed previously in Mediterranean regions indicating the absence of technologically enhanced naturally occurring radioactive material (TENORM) activities in the area. Similar results were observed for the (232)Th-series radionuclides and (40)K in the water column in comparison with the relevant literature on the Mediterranean Sea. The calculated ratios of (238)U-(232)Th and (40)K-(232)Th verified the lack of TENORM contribution in the Saronikos Gulf. Finally, a rough estimation was attempted concerning the residence times of fresh water inputs from a treatment plant of domestic wastes (Waste Water Treatment Plant of Psitalia) showing that fresh waters need a maximum of 15.7±7.6 d to be mixed with the open sea water. PMID:22539533

Evangeliou, Nikolaos; Florou, Heleny; Kritidis, Panayotis

2012-12-01

167

Etude des desequilibres radioactifs dans les familles de l'uranium par la spectrometrie gamma a basse energie et application a la datation en geologie. (Uranium series radioactive disequilibria study using gamma spectrometry with low energy and application to the dating in geology).  

National Technical Information Service (NTIS)

In this work, the gamma spectrometry with low energy has been used with the help of Ge high purity planar detector, and the means and limits of this spectrometry in the applications to the dating in geology has been studied. A geological sample taken from...

T. Khoukhi

1992-01-01

168

Radioactive Ion Beams and Radiopharmaceuticals  

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

169

Storage containers for radioactive material  

DOEpatents

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

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

1981-01-01

170

Storage containers for radioactive material  

DOEpatents

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.

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

1980-07-31

171

Managing potentially radioactive scrap metal  

SciTech Connect

The National Council on Radiation Protection and Measurements published NCRP Report No. 141 on November 19, 2002. Contract DE-FG02-98CH10945 provided the sole support for this report titled ''Managing Potentially Radioactive Scrap Metal.'' Some preliminary work supported by the U.S. Environmental Protection Agency that led to an NCRP Letter Report provided some background information for this work. NCRP Report No. 141 provides recommendations on the methodologies and techniques available to the United States for disposing of radioactive, contaminated scrap metals.

None

2002-11-19

172

Induced radioactivity in LDEF components  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

173

Politics of Radioactive Waste Disposal  

SciTech Connect

What role does public acceptance play in the siting of facilities and the selection of technologies designed to manage nuclear waste That's the question posed by Ray Kemp in The Politics of Radioactive Waste Disposal. To answer this question, Kemp assesses and compares the decision-making processes in Western Europe, Canada, and the United States.

Kemp, R.

1994-01-01

174

Electrodynamic radioactivity detector for microparticles  

SciTech Connect

A new technique for the measurement of the radioactive decay of single microparticles has been demonstrated. Although the experiments were made with droplets of order 20 ..mu..m in diameter, microparticles in the range 0.1--100 ..mu..m can be accommodated. An electrodynamic balance and combination light-scattering photometer were used to measure the charge-loss rate and size of a charged microsphere suspended in a laser beam by superposed ac and dc electrical fields. The charged particle undergoes charge loss in the partially ionized gas atmosphere which results from radioactive decay of /sup 14/C-tagged compounds, and the rate of charge loss is proportional to the rate of decay here. The charge on a particle was determined by measuring the dc voltage necessary to stably suspend the particle against gravity while simultaneously determining the droplet size by light-scattering techniques. The parameters which affect the operation of the electrodynamic balance as a radioactivity detector are examined, and the limits of its sensitivity are explored. Radioactivity levels as low as 120 pCi have been measured, and it appears that by reducing the background contamination inside our balance activity levels on the order of 10 pCi can be detected. This new technique has application in the measurement of activity levels and source discrimination of natural and man-made aerosols and smokes and is also useful for studies involving specifically labeled radio-chemical probes.

Ward, T.L.; Davis, E.J.; Jenkins R.W. Jr.; McRae, D.D.

1989-03-01

175

Radioactive Gas in Mineral Springs  

Microsoft Academic Search

IN a letter to NATURE of August 13, 1903, it was announced that experiments carried out at the Blythswood Laboratory had shown the presence of a radio-active constituent in the gases derived from the mineral waters of Bath. An account of our further investigations has been given in a paper read before the Royal Philosophical Society of Glasgow, November 18,

Blythswood; H. S. Allen

1904-01-01

176

Radioactive waste: Politics and technology  

SciTech Connect

This book presents an analysis of the divergent strategies used to forge radioactive waste policies in great Britain, Germany, and Sweden. Some basic knowledge of nuclear technology and its public policy development is needed. The book points out that developing institutional frameworks that permit agreement and consent is the principal challenge of radwaste management and places the problem of consent in an institutional framework.

Berkhout, F.

1995-08-01

177

Radioactivity and the Biology Teacher  

ERIC Educational Resources Information Center

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)

Hornsey, D. J.

1974-01-01

178

METHOD OF PURIFYING RADIOACTIVE WATER  

Microsoft Academic Search

The utilization of lithothamnium calcareum as an ion exchanger for the ; decontamination of radioactive water is described. In order to retain cobalt and ; strontium the ion exchanger is mixed with calcium silicate or borate; ; alternatively sodium phosphate is added to the water prior to the purification ; process. (NPO)

D. Acfi; M. Schmitt; M. Neveu

1959-01-01

179

Acid Digestion of Combustible Radioactive Wastes.  

National Technical Information Service (NTIS)

The following conclusions resulted from operation of Radioactive Acid Digestion Test Unit (RADTU) for processing transuranic waste: (1) the acid digestion process can be safely and efficiently operated for radioactive waste treatment.; (2) in transuranic ...

C. R. Allen M. D. Crippen R. E. Lerch R. G. Cowan

1982-01-01

180

49 CFR 175.705 - Radioactive contamination.  

Code of Federal Regulations, 2010 CFR

...aircraft operator shall notify the offeror at the earliest practicable moment following any incident in which there has been breakage, spillage, or suspected radioactive contamination involving Class 7 (radioactive) materials...

2010-10-01

181

Radioactive nuclides in the living environment.  

National Technical Information Service (NTIS)

There are several radioactive nuclides in the living environment, such as those existing since the creation of the earth, those coming from experimental nuclear explosions, and radiations of the cosmic rays. A lesson on these radioactive nuclides was cons...

K. Ueno M. Hoshi

1993-01-01

182

Radioactive Waste Incineration: Status Report  

SciTech Connect

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)

Diederich, A.R.; Akins, M.J. [WorleyParsons, Reading, PA (United States)

2008-07-01

183

Life cycle management of radioactive materials packaging  

Microsoft Academic Search

The objective of life cycle management of radioactive materials packaging is to ensure the safety functions (i.e. containment of radioactivity, protection against radiation, and criticality safety for fissile contents) during the entire life cycle of the packaging in storage, transportation and disposal. A framework has been developed for life cycle management regarding type B radioactive and fissile materials packaging, drawing

Y. Liu; S. Bellamy; J. Shuler

2007-01-01

184

Radioactivity of the JINR Site Environment.  

National Technical Information Service (NTIS)

The results of the study of the existing levels of enviromental radioactivity in the JINR region for 1971-1975; content of radioactive products in the grass and surface soil layer, levels of the total alpha - and beta-radioactivity of water of open reserv...

S. I. Alenitskaya V. P. Bamblevskii A. N. Kargin M. M. Komochkov

1977-01-01

185

Laser Trapping of Radioactive Atoms  

NASA Astrophysics Data System (ADS)

Stuart Freedman conceived the idea of laser trapping radioactive atoms for the purpose of studying beta correlation effects. ``This is really the theorist's view of a radioactive source,'' as he fondly claimed. It is ideal because the atoms form a point source, compressed in both position and momentum space, with no material walls nearby. The Berkeley group succeeded in trapping ^21Na (half-life = 22 s) atoms [Lu et al., PRL 72, 3791 (1994)], and determined its beta-neutrino correlation coefficient a=0.5502(60) to be in agreement with the Standard Model [Vetter et al., PRC 77, 035502 (2008)]. Other groups have joined this effort with searches for scalar or tensor couplings in the weak interaction. Moreover, the technique has been extended to trap very short lived ^8He (0.1 s) to study its halo structure or the very long lived ^81Kr (230,000 yr) to map the movement of groundwater.

Lu, Zheng-Tian

2013-04-01

186

Environmental Geochemistry of Radioactive Contamination  

NASA Astrophysics Data System (ADS)

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.

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

2003-12-01

187

Radioactive fuel cell storage rack  

SciTech Connect

A radioactive fuel cell storage rack is comprised of structural elements including elements which are hollow and cruciform in section. Each leg of the cruciform structural element includes a neutron shield therein. The free end of the legs of the cruciform structural element converge so as to have an included angle of approximately 90/sup 0/. The rack is comprised of such cruciform elements as well as cooperating elements which are generally T and L shaped in section.

Holtz, M.; Singh, K.P.

1983-05-03

188

Radioactive Microspheres for Medical Applications  

Microsoft Academic Search

This paper reviews the preparation and application of radioactive microspheres for medical purposes. It first discusses the\\u000a properties of relevant radioisotopes and then explores the diagnostic uses of gamma-emitter labelled microspheres, such as\\u000a blood flow measurement and imaging of the liver and other organs. The therapeutic uses of alpha- and beta-emitting microspheres,\\u000a such as radioembolization, local tumour therapy and radiosynovectomy,

Urs HÄfeli

189

Radioactive Waste Management BasisApril 2006  

SciTech Connect

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.

Perkins, B K

2011-08-31

190

Measurement of natural radioactive nuclide concentrations in various metal ores used as industrial raw materials in Japan and estimation of dose received by workers handling them.  

PubMed

Natural resources such as ores and rocks contain natural radioactive nuclides at various concentrations. If these resources contain high concentrations of natural radioactive nuclides, workers handling them might be exposed to significant levels of radiation. Therefore, it is important to investigate the radioactive activity in these resources. In this study, concentrations of radioactive nuclides in Th, Zr, Ti, Mo, Mn, Al, W, Zn, V, and Cr ores used as industrial raw materials in Japan were investigated. The concentrations of (238)U and (232)Th were determined by inductively coupled plasma mass spectrometry (ICP-MS), while those of (226)Ra, (228)Ra, and (40)K were determined by gamma-ray spectrum. We found the concentrations of (238)U series, (232)Th series, and (40)K in Ti, Mo, Mn, Al, W, Zn, V, and Cr ores to be lower than the critical values defined by regulatory requirements as described in the International Atomic Energy Agency (IAEA) Safety Guide. The doses received by workers handling these materials were estimated by using methods for dose assessment given in a report by the European Commission. In transport, indoor storage, and outdoor storage scenarios, an effective dose due to the use of Th ore was above 4.3 x 10(-2)Sv y(-1), which was higher than that of the other ores. The maximum value of effective doses for other ores was estimated to be about 4.5 x 10(-4)Sv y(-1), which was lower than intervention exemption levels (1.0 x 10(-3)Sv y(-1)) given in International Commission of Radiological Protection (ICRP) Publication 82. PMID:19703725

Iwaoka, Kazuki; Tagami, Keiko; Yonehara, Hidenori

2009-11-01

191

Radon daughter disequilibria in the lower marine boundary layer  

Microsoft Academic Search

Radon daughters are produced as free ions, but they become attached to aerosol particles at a rate depending on the particle concentration. In the lower marine boundary layer, most of those which do not become attached plate out on the ocean surface. In this paper a simple model is used to examine the influence of several parameters on radon\\/radon daughter

S. Whittlestone; Private MailBag

1990-01-01

192

Trace gas disequilibria during deep-water formation  

Microsoft Academic Search

We present high-precision measurements by a new isotope dilution technique of a suite of inert gases in the North Pacific. Remarkably smooth gradients in Ar, Kr and Xe from near equilibrium in intermediate waters to several percent undersaturated in deep waters were observed. The general pattern in the deepest waters was that Ar, Kr and Xe were undersaturated (Ar least

Roberta C. Hamme; Jeffrey P. Severinghaus

193

Trace gas disequilibria during deep-water formation  

Microsoft Academic Search

We present high-precision measurements by a new isotope dilution technique of a suite of inert gases in the North Pacific. Remarkably smooth gradients in Ar, Kr and Xe from near equilibrium in intermediate waters to several percent undersaturated in deep waters were observed. The general pattern in the deepest waters was that Ar, Kr and Xe were undersaturated (Ar least

Roberta C. Hamme; Jeffrey P. Severinghaus

2007-01-01

194

Assessing Postzygotic Isolation Using Zygotic Disequilibria in Natural Hybrid Zones  

PubMed Central

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.

Hu, Xin-Sheng; Yeh, Francis C.

2014-01-01

195

Artificial Radioactivity of Ti45  

Microsoft Academic Search

A radioactive isotope possessing a half-life of 3.08+\\/-0.06 hours has been produced by four different types of bombardment. Evidence is presented which indicates that the activity should be assigned to Ti45. The four nuclear reactions are: Ca42+He4-->Ti45+n1 Sc45+H2-->Ti45+2n1Sc45+H1-->Ti45+n1 Ti46+n1-->Ti45+2n1. Nuclear spin considerations indicate that a fifth reaction, Ti46(gamma,n)Ti45, is improbable, as was verified experimentally. Analysis of cloud-chamber pictures reveals the

J. S. Allen; M. L. Pool; J. D. Kurbatov; L. L. Quill

1941-01-01

196

Radioactive beams with the HHIRF accelerators  

SciTech Connect

There is an increasing interest in radioactive ion beams for astrophysics and nuclear physics research and applied programs. This interest has led to an International Conference on Radioactive Nuclear Beams and a Workshop on the Science of Intense Radioactive Ion Beams. In addition, a steering committee has been formed to consider the development of a very large and intense RIB facility in North America to produce both proton- and neutron-rich beams. This report discusses development of these beams.

Olsen, D.K.; Alton, G.D.; Baktash, C.; Dowling, D.T.; Garrett, J.D.; Haynes, D.L.; Jones, C.M.; Juras, R.C., Lane, S.N.; Lee, I.Y.; Meigs, M.J.; Mills, G.D.; Mosko, S.W.; Tatum, B.A. Toth, K.S. (Oak Ridge National Lab., TN (USA)); Carter, H.K. (UNISOR, Oak Ridge, TN (USA))

1991-01-01

197

Spontaneously generated radioactive nanoparticles in the environment  

NASA Astrophysics Data System (ADS)

For almost 100 years, and perhaps longer, observers have detected spontaneous dispersal of radioactivity from macroscopic quantities of radioactive materials with the first published observations reported in 1910. In the 1960"s and later, radioactivity was observed to migrate through HEPA filters de-spite their well-established filtration characteristics. In measurements of ground water, radioactivity has been found to disperse from its original location of deposition in soil, despite the size, insolubility, and resistance to chemical reactions of the radioactive particles originally deposited. Similarly, measurements of the uptake of these materials in lung tissue and studies of their solubility in simulated biological fluids showed the solubility to be related to the radioactivity of the materials. In numerous practical examples, the migration and deposition of radioactivity affects work and operational practices. Despite this long and varied history indicating the importance of self-dispersal of radioactive materials, no measurements had ever been reported of the materials which were actually dispersed until recently and the results are quite surprising, suggesting a well-defined process creating discrete nanoparticle fractions. This paper will review the history of the observations of spontaneous dispersal of radioactivity and close with a description of the first measure-ments of the dispersed nanoparticles and suggestions of the physical processes involved in their formation.

Marlow, William H.; Cheng, Yung-Sung

2003-04-01

198

Student Understanding of Ionizing Radiation and Radioactivity  

NSDL National Science Digital Library

This article describes how researchers identified specific difficulties students had with ionizing radiation and radioactivity using interviews. They also explore students' pre-instruction thoughts on these topics.

Prather, Edward E.; Harrington, Randal R.

2006-06-19

199

Radioactive material package seal tests  

SciTech Connect

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.

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

1990-01-01

200

Cosmic radioactivity and INTEGRAL results  

NASA Astrophysics Data System (ADS)

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.

Diehl, Roland

2014-05-01

201

Induced radioactivity in LDEF components  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

202

Radioactivity in the galactic plane  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

203

Radioactive Waste Disposal Implications of Extending Part IIA to cover Radioactively Contaminated Land  

Microsoft Academic Search

A short study has been carried out of the potential radioactive waste disposal issues associated with the proposed extension of Part IIA to address radioactively contaminated land, where there is no other suitable existing legislation. It was found that there is likely to be an availability problem with respect to disposal at landfills of the radioactive wastes arising from remediation.

DJ Nancarrow

204

Method of preparing bodies containing radioactive substances  

US Patent & Trademark Office Database

Radioactive substances are disposed of by incorporating glass particles containing the radioactive substance in molten metal, heat treating the molten metal containing the glass particles to convert the glass to glass ceramic, and cooling the resulting composite to solidify the metal and provide the glass ceramic particles embedded in a matrix of the metal.

1980-06-24

205

Physics with beams of radioactive nuclei  

SciTech Connect

A survey of the latest results from experiments devoted to studying the structure of nuclei and nuclear-reaction mechanisms by means of accelerated radioactive beams is given. Results obtained in Dubna with the aid of the DRIBs accelerator complex and at other radioactive-beam factories are presented.

Penionzhkevich, Yu. E., E-mail: pyuer@lnr.jinr.r [Joint Institute for Nuclear Research (Russian Federation)

2008-07-15

206

Acid digestion of combustible radioactive wastes  

Microsoft Academic Search

The following conclusions resulted from operation of Radioactive Acid Digestion Test Unit (RADTU) for processing transuranic waste: (1) the acid digestion process can be safely and efficiently operated for radioactive waste treatment.; (2) in transuranic waste treatment, there was no detectable radionuclide carryover into the exhaust off-gas. The plutonium decontamination factor (DF) between the digester and the second off-gas tower

C. R. Allen; R. E. Lerch; M. D. Crippen; R. G. Cowan

1982-01-01

207

Local area networks in radioactivity measurements  

Microsoft Academic Search

We describe the operation of a Local Area Network at Nuclear Chemistry Laboratory involved in surveillance of environmental radioactivity. Detailed consideration is given separately to computer and network hardware, radiation instrument interfacing, software, as well as operations. The application of a Local Area Network offers considerable improvements in the laboratory preformance, quality assurance of radioactivity analyses, and data reporting.

T. M. Semkow; C. D. Schwenker; M. E. Kitto; J. C. Daly

1994-01-01

208

Radioactivity in Trinitite six decades later  

Microsoft Academic Search

The first nuclear explosion test, named the Trinity test, was conducted on July 16, 1945 near Alamogordo, New Mexico. In the tremendous heat of the explosion, the radioactive debris fused with the local soil into a glassy material named Trinitite. Selected Trinitite samples from ground zero (GZ) of the test site were investigated in detail for radioactivity. The techniques used

Pravin P. Parekh; Thomas M. Semkow; Miguel A. Torres; Douglas K. Haines; Joseph M. Cooper; Peter M. Rosenberg; Michael E. Kitto

2006-01-01

209

Physical protection of radioactive material in transit  

Microsoft Academic Search

From conference on transportation of radioactive material; ; Charlottesville, Virginia, USA (26 Oct 1970). In conference on transportation of ; radioactive material held in Charlottesville, Virginia on 26-27 October 1970. ; Regulations pertaining to physical protection of fissile materials during transit ; are briefly discussed. Case histories of misrouted or misplaced shipments are ; given. Some corrective actions to prevent

Wischow

1970-01-01

210

Overview of Radioactive Waste Disposal at Sea  

Microsoft Academic Search

For hundreds of years, the seas have been used as a place to dispose of wastes from human activities. Although no high level radioactive waste has been disposed of into the sea, variable amounts of packaged low level radioactive wastes have been dumped at 47 sites in the northern part of the Atlantic and Pacific Oceans. in 1946 the first

Dominique Calmet

1992-01-01

211

BWR-GALE. BWR Effluent Radioactivity Releases  

Microsoft Academic Search

BWR-GALE is a mathematical model for calculating the expected annual releases of radioactive material in gaseous and liquid effluents from boiling water reactors (BWRs). The calculations are based on data generated from operating reactors, field tests, laboratory tests, and plant-specific design considerations incorporated to reduce the quantity of radioactive materials that may be released to the environment. There are two

Cardile

1979-01-01

212

RECENT RESULTS FROM ALPINE AIR RADIOACTIVITY MEASUREMENTS  

Microsoft Academic Search

By means of various diagrams, the transient pattern of the natural and ; artificial radioactivity and of air impurities in 1959 at a valley and a ; neighboring mountain station was represented and described. It was shown that ; the air layer near the ground added more long-lived radioactive substances by ; repeated eddying up from the ground than from

1960-01-01

213

Diverter assembly for radioactive material  

DOEpatents

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.

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

1988-04-11

214

Microbiological treatment of radioactive wastes  

SciTech Connect

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.

Francis, A.J.

1992-12-31

215

Method for immobilizing radioactive iodine  

DOEpatents

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.

Babad, Harry (Richland, WA); Strachan, Denis M. (Richland, WA)

1980-01-01

216

Environmental geochemistry of radioactive contamination.  

SciTech Connect

This report attempts to describe the geochemical foundations of the behavior of radionuclides in the environment. The information is obtained and applied in three interacting spheres of inquiry and analysis: (1) experimental studies and theoretical calculations, (2) field studies of contaminated and natural analog sites and (3) model predictions of radionuclide behavior in remediation and waste disposal. Analyses of the risks from radioactive contamination require estimation of the rates of release and dispersion of the radionuclides through potential exposure pathways. These processes are controlled by solubility, speciation, sorption, and colloidal transport, which are strong functions of the compositions of the groundwater and geomedia as well as the atomic structure of the radionuclides. The chemistry of the fission products is relatively simple compared to the actinides. Because of their relatively short half-lives, fission products account for a large fraction of the radioactivity in nuclear waste for the first several hundred years but do not represent a long-term hazard in the environment. The chemistry of the longer-lived actinides is complex; however, some trends in their behavior can be described. Actinide elements of a given oxidation state have either similar or systematically varying chemical properties due to similarities in ionic size, coordination number, valence, and electron structure. In dilute aqueous systems at neutral to basic pH, the dominant actinide species are hydroxy- and carbonato-complexes, and the solubility-limiting solid phases are commonly oxides, hydroxides or carbonates. In general, actinide sorption will decrease in the presence of ligands that complex with the radionuclide; sorption of the (IV) species of actinides (Np, Pu, U) is generally greater than of the (V) species. The geochemistry of key radionuclides in three different environments is described in this report. These include: (1) low ionic strength reducing waters from crystalline rocks at nuclear waste research sites in Sweden; (2) oxic water from the J-13 well at Yucca Mountain, Nevada, the site of a proposed repository for high level nuclear waste (HLW) in tuffaceous rocks; and (3) reference brines associated with the Waste Isolation Pilot Plant (WIPP). The transport behaviors of radionuclides associated with the Chernobyl reactor accident and the Oklo Natural Reactor are described. These examples span wide temporal and spatial scales and include the rapid geochemical and physical processes important to nuclear reactor accidents or industrial discharges as well as the slower processes important to the geologic disposal of nuclear waste. Application of geochemical information to remediating or assessing the risk posed by radioactive contamination is the final subject of this report. After radioactive source terms have been removed, large volumes of soil and water with low but potentially hazardous levels of contamination may remain. For poorly-sorbing radionuclides, capture of contaminated water and removal of radionuclides may be possible using permeable reactive barriers and bioremediation. For strongly sorbing radionuclides, contaminant plumes will move very slowly. Through a combination of monitoring, regulations and modeling, it may be possible to have confidence that they will not be a hazard to current or future populations. Abstraction of the hydrogeochemical properties of real systems into simple models is required for probabilistic risk assessment. Simplifications in solubility and sorption models used in performance assessment calculations for the WIPP and the proposed HLW repository at Yucca Mountain are briefly described.

Bryan, Charles R.; Siegel, Malcolm Dean

2003-09-01

217

Atmospheric xenon radioactive isotope monitoring.  

PubMed

The Comprehensive Nuclear Test Ban Treaty (CTBT) organisation is implementing a world-wide monitoring network in order to check that the State Signatories comply with the treaty. One of the monitoring facilities consists of an atmospheric noble gas monitoring equipment. According to the requirements annexed in the treaty, the French Atomic Energy Commission (CEA) developed a device, called SPALAX, which automatically extracts xenon from ambient air and makes in situ measurements of the activities of four xenon radioisotopes (131mXe, 133mXe, 133Xe, 135Xe). The originality of this device is noticeable essentially in the gas sample processing method: thanks to the coupling of a gas permeator and of a noble gas specific adsorbent, it can selectively extract and concentrate xenon to more than 3 x 10 E6. This process is carried out continuously without cryogenic cooling, without any regeneration time. The detection of the xenon radioactive isotopes is done automatically by high spectral resolution gamma spectrometry, a robust technology well-suited for on-field instrumentation. In the year 2000, a prototype was involved in an international evaluation exercise directed by the CTBT organisation (CTBTO). This exercise demonstrated that the SPALAX equipment perfectly met the requirements of the CTBTO for such systems. On the basis of the continuous 24-h resolution record of the atmospheric xenon radioactive isotopes concentrations, the SPALAX system also demonstrated that ambient levels of 133Xe can fluctuate quickly from less than the detection limit to over 40 x 10(-3) Bq m(-3). In order to build an industrial version of this equipment, the CEA entered into a partnership with a French engineering company (S.F.I., Marseille, France), which is now able to produce an industrial version of SPALAX, i.e. more compact and more efficient than the prototypes. The 133Xe minimum detectable concentration is 0.15 x 10(-3) Bq m(-3) air per 24 h sampling cycle. PMID:15162864

Fontaine, J P; Pointurier, F; Blanchard, X; Taffary, T

2004-01-01

218

[Examination of radioactive contamination in foods].  

PubMed

Following the Fukushima nuclear plant accident in Mar. 2011, the examination of radioactive contamination in foods is being carried out in Nagoya. During the period between 30 Mar. 2011 and 31 Oct. 2012, a total of 300 food samples were collected and the concentrations of radioactive nuclides were determined by means of ?-ray spectrometry using a high-purity germanium semiconductor detector. The results of analysis indicate that the concentrations of radioactive iodine (I) and cesium (Cs) were below the regulatory limits. Radioactive I ((131)I) was detected in 7 samples which belonged to the categories of green and yellow vegetables and other vegetables. Radioactive Cs ((134)Cs and (137)Cs) was detected in 60 samples which belonged to the categories of rice and its processed products, potatoes and its processed products, nuts and seeds, green and yellow vegetables, other vegetables, fruits, mushrooms, fishes and shellfishes, processed sea foods, meat, milk and dairy products and other beverages. PMID:23676695

Miyazaki, Hitoshi; Tsuchiyama, Tomoyuki; Terada, Hisaya

2013-01-01

219

The safe disposal of radioactive wastes  

PubMed Central

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.

Kenny, A. W.

1956-01-01

220

Apparatus and method for radioactive waste screening  

DOEpatents

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.

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

2012-09-04

221

Report of radioactivity survey research in fiscal year 1989.  

National Technical Information Service (NTIS)

In the National Institute of Radiological Sciences, as a part of the radioactivity survey and research of Science and Technology Agency, the survey of environmental radioactivity level due to the radioactive fallout accompanying nuclear explosion experime...

1990-01-01

222

Hydrogen production during processing of radioactive sludge containing noble metals.  

National Technical Information Service (NTIS)

Hydrogen was produced when radioactive sludge from Savannah River Site radioactive waste containing noble metals was reacted with formic acid. This will occur in a process tank in the Defense Waste Facility at SRS when waste is vitrified. Radioactive slud...

B. C. Ha D. M. Ferrara N. E. Bibler

1992-01-01

223

Report of radioactivity survey research in fiscal year 1988.  

National Technical Information Service (NTIS)

The National Institute of Radiological Sciences has been surveyed, as part of the radioactivity research project by the Science and Technology Agency, radioactivity levels in the environment and safety analysis for radioactive fallouts associated with nuc...

1989-01-01

224

40 CFR 141.25 - Analytical methods for radioactivity.  

Code of Federal Regulations, 2010 CFR

...141.25 - Analytical methods for radioactivity.] 40 PROTECTION OF ENVIRONMENT...Sec. 141.25 Analytical methods for radioactivity. (a) Analysis for the following...determine compliance with Sec. 141.66 (radioactivity) in accordance with the methods...

2009-07-01

225

Hanford Site radioactive solid waste acceptance criteria  

SciTech Connect

Westinghouse Hanford Company manages and operates the Hanford Site 200 Area radioactive solid waste treatment, storage, and disposal facilities for the US Department of Energy-Richland Operations Office. These facilities include radioactive solid waste disposal sites and radioactive solid waste storage areas. This manual defines the criteria that must be met by waste generators for radioactive solid waste to be accepted by Westinghouse Hanford Company for storage or disposal at the 200 Area facilities. It is to be used by all waste generators preparing radioactive solid waste for storage or disposal at the Hanford Site facilities. This manual is also intended for use by Westinghouse Hanford Company solid waste technical staff involved with approval and acceptance of radioactive solid waste. The criteria in this manual represent a compilation of state and federal regulation, US Department of Energy Orders, Hanford Site requirements, and other rules, regulations, guidelines, and standards as they apply to management of radioactive solid waste. Where appropriate, these requirements are included in the manual by reference. It is the intent of this manual to provide guidance to the waste generator in meeting the applicable requirements. 11 refs.

Stickney, R.G.

1990-01-01

226

A radioactive metal processing industry perspective source.  

PubMed

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

Johnson, A

2006-11-01

227

Natural radioactivity in groundwater--a review.  

PubMed

The issue of natural radioactivity in groundwater is reviewed, with emphasis on those radioisotopes which contribute in a significant way to the overall effective dose received by members of the public due to the intake of drinking water originating from groundwater systems. The term 'natural radioactivity' is used in this context to cover all radioactivity present in the environment, including man-made (anthropogenic) radioactivity. Comprehensive discussion of radiological aspects of the presence of natural radionuclides in groundwater, including an overview of current regulations dealing with radioactivity in drinking water, is provided. The presented data indicate that thorough assessments of the committed doses resulting from the presence of natural radioactivity in groundwater are needed, particularly when such water is envisaged for regular intake by infants. They should be based on a precise determination of radioactivity concentration levels of the whole suite of radionuclides, including characterisation of their temporal variability. Equally important is a realistic assessment of water intake values for specific age groups. Only such an evaluation may provide the basis for possible remedial actions. PMID:22166151

Dinh Chau, Nguyen; Dulinski, Marek; Jodlowski, Pawel; Nowak, Jakub; Rozanski, Kazimierz; Sleziak, Monika; Wachniew, Przemyslaw

2011-12-01

228

Influence of Radioactivity on Surface Interaction Forces  

SciTech Connect

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.

Walker, Mark E [ORNL; McFarlane, Joanna [ORNL; Glasgow, David C [ORNL; Chung, Eunhyea [Georgia Institute of Technology; Taboada Serrano, Patricia L [ORNL; Yiacoumi, Sotira [Georgia Institute of Technology; Tsouris, Costas [ORNL

2010-01-01

229

Disposal of low-level radioactive wastes.  

PubMed

The generation of low-level radioactive waste is a natural consequence of the societal uses of radioactive materials. These uses include the application of radioactive materials to the diagnosis and treatment of human disease and to research into the causes of human disease and their prevention. Currently, low level radioactive wastes are disposed of in one of three shallow land-burial disposal sites located in Washington, Nevada, and South Carolina. With the passage in December 1980 of Public Law 96-573, "The Low-Level Radioactive Waste Policy Act," the disposal of low-level wastes generated in each state was identified as a responsibility of the state. To fulfill this responsibility, states were encouraged to form interstate compacts for radioactive waste disposal. At the present time, only 37 states have entered into compact agreements, in spite of the clause in Public Law 96-573 that established January 1, 1986, as a target date for implementation of state responsibility for radioactive wastes. Recent action by Congress has resulted in postponement of the implementation date to January 1, 1993. PMID:3749914

Hendee, W R

1986-07-01

230

Radioactive anomaly discrimination from spectral ratios  

DOEpatents

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.

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

2013-08-20

231

Science with radioactive beams: the alchemist's dream  

NASA Astrophysics Data System (ADS)

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.

Gelletly, W.

2001-05-01

232

Field tests using radioactive matter.  

PubMed

During recent years, the assessment of possible radiological consequences of a terrorist attack associated with a release of radioactive substances (RaS) has been in the focus of interest of emergency preparedness and radiation protection specialists, as well as experts dealing with the dispersion of harmful substances in the atmosphere. Suitable tools for these analyses are applications of mathematical and physical models and simulation of this attack under 'realistic' conditions. The work presented here summarises the results of four tests, in which a RaS (a Tc-99 m solution) was dispersed over a free area with the use of an industrial explosive. Detection methods and techniques employed in these tests are described and values characterising the RaS dispersion--dose rates, surface activities in horizontal and vertical directions, volume activities, their space and time distributions and mass concentrations of aerosols produced after the explosion are presented and compared. These data will be applied to a comparison of outcomes of models used for the assessment of radiation accidents as well as in future field tests carried out under conditions of more complex geometry (indoor environment, terrain obstacles, etc.). PMID:20089512

Prouza, Z; Beckova, V; Cespirova, I; Helebrant, J; Hulka, J; Kuca, P; Michalek, V; Rulik, P; Skrkal, J; Hovorka, J

2010-06-01

233

Radioactivity distribution in the MAFF beamline  

NASA Astrophysics Data System (ADS)

The Munich Accelerator for Fission Fragments (MAFF) facility planned at the research reactor FRM-II in Munich is dedicated to produce, cool and accelerate high-intensity neutron-rich radioactive beams. The radioactive beam of fission fragments results from bombarding a uranium target by the thermal neutrons emerging from the reactor. Part of the nuclides is released from the target/ion source unit in a non-ionized state. This contribution is concerned with simulating the distribution of the non-ionized radioactivity along the MAFF beamline. The calculations are performed with the help of the computer program MOVAK3D. The calculated fraction of non-ionized radioactivity at the border of the experimental area is at the level of about 10 -7, relative to the activity produced in the target.

Szerypo, J.; Gross, M.; Grossmann, R.; Habs, D.; Kester, O.; Maier, H.-J.; Thirolf, P.; Zech, E.; Faestermann, T.; Krücken, R.; Maier-Komor, P.; Nebel, F.

2006-05-01

234

Radioactive Residues. Current and Prospective Problems.  

National Technical Information Service (NTIS)

After having described the principal characteristics of radioactive residues, the author examined the current problems posed by liquid and gaseous effluents and stressed that nuclear installations are definitely much less polluting, with an identical powe...

A. Gauvenet

1975-01-01

235

Radioactive isotopes in solid-state physics  

Microsoft Academic Search

Radioactive atoms have been used in solid-state physics and in material science for many decades. Besides their classical application as tracer for diffusion studies, nuclear techniques such as M\\\\\\

Manfred Deicher

2002-01-01

236

Radioactive materials shipping cask anticontamination enclosure  

DOEpatents

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.

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

1982-01-01

237

Radioactive Acid Digestion Test Unit (RADTU), 1980.  

National Technical Information Service (NTIS)

The Radioactive Acid Digestion Test Unit (RADTU) was constructed at the Hanford Site, Richland, WA to demonstrate application of the acid digestion process for treating combustible transuranic wastes and scrap materials. Using its original tray digester v...

C. R. Allen

1980-01-01

238

Air Pollution Aspects of Radioactive Substances.  

National Technical Information Service (NTIS)

Contents: Radioactive substances' Effects on humans (Types of exposure, Biological effects (Somatic effects, Leukemia, Other cancers, Cataracts, Effect on life span), Genetic effects, Acute exposure), Effects on animals; Effects on plants; Effects on mate...

S. Miner

1969-01-01

239

Environmental Radioactivity in Greenland in 1979.  

National Technical Information Service (NTIS)

Measurements of fallout radioactivity in Greenland in 1979 are reported. Strontium-90 (and Cesium-137 in most cases) was determined in samples of precipitation, sea water, vegetation, animals, and drinking water. Estimates are given of the mean contents o...

A. Aarkrog H. Dahlgaard E. Holm J. Lippert K. Nilsson

1980-01-01

240

Radioactive Dating: A Method for Geochronology.  

ERIC Educational Resources Information Center

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)

Rowe, M. W.

1985-01-01

241

Annual radioactive waste tank inspection program - 1996.  

National Technical Information Service (NTIS)

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 s...

F. G. McNatt

1997-01-01

242

Domestic Smoke Detectors Using Radioactive Material.  

National Technical Information Service (NTIS)

Increasing numbers of technical and consumer products incorporating radioactive material are becoming available to the Australian public. One consumer device of this type coming into common use is the domestic smoke detector that uses Americium 241 in det...

1979-01-01

243

Principles for Sampling Airborne Radioactivity from Stacks  

SciTech Connect

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.

Glissmeyer, John A.

2010-10-18

244

USDOE Radioactive Waste Incineration Technology: Status Review.  

National Technical Information Service (NTIS)

Early attempts were made to incinerate radioactive wastes met with operation and equipment problems such as feed preparation, corrosion, inadequate off-gas cleanup, incomplete combustion, and isotope containment. The US Department of Energy (DOE) continue...

L. C. Borduin A. L. Taboas

1980-01-01

245

Computed tomography of radioactive objects and materials  

NASA Astrophysics Data System (ADS)

Computed tomography (CT) has been performed on a number of radioactive objects and materials. Several unique technical problems are associated with CT of radioactive specimens. These include general safety considerations, techniques to reduce background-radiation effects on CT images and selection criteria for the CT source to permit object penetration and to reveal accurate values of material density. In the present paper, three groups of experiments will be described, for objects with low, medium and high levels of radioactivity. CT studies on radioactive specimens will be presented. They include the following: (1) examination of individual ceramic reactor-fuel (uranium dioxide) pellets, (2) examination of fuel samples from the Three Mile Island reactor, (3) examination of a CANDU (CANada Deuterium Uraniun: registered trademark) nuclear-fuel bundle which underwent a simulated loss-of-coolant accident resulting in high-temperature damage and (4) examination of a PWR nuclear-reactor fuel assembly.

Sawicka, B. D.; Murphy, R. V.; Tosello, G.; Reynolds, P. W.; Romaniszyn, T.

1990-12-01

246

Studies of induced radioactivity at the AGS  

SciTech Connect

With the goals of higher proton intensities, along with the many modes the AGS now runs and those being commissioned to run, we have begun detailed studies of the beam induced radioactivity in the AGS.

Brown, K.A.; Tanaka, M.

1987-01-01

247

Radioactive materials transportation emergency response plan.  

National Technical Information Service (NTIS)

Ontario Hydro transports radioactive material between its nuclear facilities, Atomic Energy of Canada Limited at Chalk River Laboratories and Radiochemical Company in Kanata, on a regular basis. Ontario Hydro also occasionally transports to Whiteshell Lab...

N. Karmali

1987-01-01

248

RADIOACTIVITY STANDARDS DISTRIBUTION PROGRAM FY 1977  

EPA Science Inventory

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

249

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...

250

Transportation of Radioactive Materials by Air.  

National Technical Information Service (NTIS)

Canadian regulations for air transportation of radioactive materials are based on the IAEA regulations. The Atomic Energy Control Board is responsible for enforcement. The IAEA regulations are summarized in this report. A review of 402 210 shipments by ai...

J. M. Jardine

1977-01-01

251

Transport of Radioactive Material by Alpha Recoil  

SciTech Connect

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.

Icenhour, A.S.

2005-05-19

252

Sources of Radioactive Isotopes for Dirty Bombs  

Microsoft Academic Search

From the security perspective, radioisotopes and radioactive sources are not created equal. Of the many radioisotopes used in industrial applications, medical treatments, and scientific research, only eight, when present in relatively large amounts in radioactive sources, pose high security risks primarily because of their prevalence and physical properties. These isotopes are americium-241, californium-252, cesium-137, cobalt-60, iridium-192, radium-226, plutonium-238, and strontium-90.

Joel Lubenau

2004-01-01

253

Vitrification of hazardous and radioactive wastes  

SciTech Connect

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.

Bickford, D.F.; Schumacher, R.

1995-12-31

254

Transport of Radioactive Material by Alpha Recoil  

Microsoft Academic Search

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

A. S. Icenhour

2005-01-01

255

Salivary gland dysfunction following radioactive iodine therapy  

SciTech Connect

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.

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

1983-02-01

256

Coulomb excitation of radioactive 20, 21 Na  

Microsoft Academic Search

The low-energy structures of the radioactive nuclei 20, 21Na have been examined using Coulomb excitation at the TRIUMF-ISAC radioactive ion beam facility. Beams of ? 5×106 ions\\/s were accelerated to 1.7MeV\\/A and Coulomb excited in a 0.5mg\\/cm^2 natTi target. Two TIGRESS HPGe clover detectors perpendicular to the beam axis were used for -ray detection, while scattered nuclei were observed by

M. A. Schumaker; D. Cline; G. Hackman; C. Pearson; C. E. Svensson; C. Y. Wu; A. Andreyev; R. A. E. Austin; G. C. Ball; D. Bandyopadhyay; J. A. Becker; A. J. Boston; H. C. Boston; L. Buchmann; R. Churchman; F. Cifarelli; R. J. Cooper; D. S. Cross; D. Dashdorj; G. A. Demand; M. R. Dimmock; T. E. Drake; P. Finlay; A. T. Gallant; P. E. Garrett; K. L. Green; A. N. Grint; G. F. Grinyer; L. J. Harkness; A. B. Hayes; R. Kanungo; A. F. Lisetskiy; K. G. Leach; G. Lee; R. Maharaj; J. P. Martin; F. Moisan; A. C. Morton; S. Mythili; L. Nelson; O. Newman; P. J. Nolan; J. N. Orce; E. Padilla-Rodal; A. A. Phillips; M. Porter-Peden; J. J. Ressler; R. Roy; C. Ruiz; F. Sarazin; D. P. Scraggs; J. C. Waddington; J. M. Wan; A. Whitbeck; S. J. Williams; J. Wong

2009-01-01

257

PWR-GALE. PWR Effluent Radioactivity Releases  

Microsoft Academic Search

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

1992-01-01

258

Public involvement in radioactive waste management decisions  

SciTech Connect

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.

NONE

1994-04-01

259

CHAPTER 5-RADIOACTIVE WASTE MANAGEMENT  

SciTech Connect

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.

Marra, J.

2010-05-05

260

Environmental radioactivity in the Arctic, Antarctic  

SciTech Connect

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.

Palmer, H.

1993-12-01

261

Radioactivity of the moon and planets  

NASA Astrophysics Data System (ADS)

The major results of studies of the radioactivity of the moon and terrestrial planets are reviewed. Measurements of the cosmogenic and natural radioactivity of the moon and Mars were obtained from planetary orbiter measurements, and those of Venus by in situ measurements, in addition to measurements of lunar samples brought back to earth. For the case of the moon, the Western maria on the near side are found to be the most radioactive areas, with highlands on both sides of the moon exhibiting lower radioactivity than the maria and lunar radioactivity levels in general less than those of the earth, which is correlated with different chemical compositions of the two bodies. The potassium, uranium and thorium contents of the landing sites of Veneras 8, 9 and 10 are shown to differ from each other, but be similar to those of terrestrial basalts, which they also resemble in density. Gamma-radiation and X-ray fluorescence measurements of Mars indicate the content of natural radioelements to be similar to that of the eruptive rocks of the earth crust, with Martian rocks of volcanic formations similar to terrestrial and lunar basalts, and those of the ancient terra formations more closely resembling the anorthosite-norite-troctolite association of the lunar highlands. It is pointed out that natural radioelements contents of all the bodies examined indicate a single chemical differentiation process, while cosmogenic radiation contents can aid in determining cosmic ray intensities as well as the sequences of geological events.

Surkov, Iu. A.

262

Security in the Transport of Radioactive Materials  

SciTech Connect

The United States Department of Energy National Nuclear Security Administration's (DOE/NNSA)Global Threat Reduction Initiative (GTRI), the International Atomic Energy Agency (IAEA) and active IAEA Donor States are working together to strengthen the security of nuclear and radioactive materials during transport to mitigate the risks of theft, diversion, or sabotage. International activities have included preparing and publishing the new IAEA guidance document Security in the Transport of Radioactive Material while ensuring that security recommendations do not conflict with requirements for safety during transport, and developing and providing training programs to assist other countries in implementing radioactive material transport security programs. This paper provides a brief update on the status of these transportation security efforts.

Pope, Ron [Oak Ridge National Laboratory (Retired); Rawl, Richard R [ORNL

2010-01-01

263

Wide range radioactive gas concentration detector  

DOEpatents

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.

Anderson, David F. (Los Alamos, NM)

1984-01-01

264

Completion of the Radioactive Materials Packaging Handbook  

SciTech Connect

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.

Shappert, L.B.

1998-02-01

265

Low radioactivity spectral gamma calibration facility  

SciTech Connect

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.

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

266

Summary -- Experiments with Radioactive Beams Working Group  

SciTech Connect

During the course of the workshop, a wide range of futuristic radioactive-beam experiments were discussed. These extended from the study of electroweak interactions in nuclei to materials science, nuclear astrophysics, and a host of nuclear physics investigations. Emphasis was placed on illustrating how these prototypical experiments could be done, discussing what types of detection systems would be needed, exploring the new problems which would be confronting the radioactive beam experimenter, and better defining the beam requirements. Contained herein is a summary of these discussions.

Vieira, D.J. [Los Alamos National Lab., NM (United States); Wiescher, M. [Notre Dame Univ., IN (United States)

1992-12-31

267

MCNP5 code in radioactive particle tracking.  

PubMed

Radioactive particle tracking techniques have been widely applied in the field of chemical engineering, especially in hydrodynamics in multiphase reactors. In classical approach, the phenomenological model is used to simulate the number of counts measured by the detector and then the tracer position is reconstructed by solving a minimisation problem between the measured events and the mentioned model. The paper presents an original algorithm for reconstruction of the tracer position during the radioactive particle tracking based on the Monte Carlo N-Particle code version 5. The validation of the proposed algorithm is evaluated for two cases: 'ideal' and physically realistic. The advantages of the new algorithm are demonstrated. PMID:21601465

Mosorov, Volodymyr; Abdullah, Jaafar

2011-09-01

268

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

SciTech Connect

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.

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

2011-01-01

269

Fabrication of radioactive stents by ion implantation  

Microsoft Academic Search

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

Erhard Huttel; Johann Kaltenbaek; Klaus Schloesser; Hermann Schweickert

2002-01-01

270

Radioactive Waste Management: Yesterday, Today and Tomorrow.  

National Technical Information Service (NTIS)

The public believes that there is a radioactive waste problem, but knowledge in the field is so well advanced that the only problem left is how to choose the most economically effective method among many available. Tailings from uranium ore processing cou...

A. T. Prince

1977-01-01

271

Radioactive nuclei in material science research  

Microsoft Academic Search

Radioactive nuclei are used as probes to study structure and dynamical processes in solids on a microscopic scale. Out of the broad field of applications only a few examples are discussed to illustrate how local structure information is obtained using nuclear probes.

H.-E. Mahnke

1995-01-01

272

Method for decontamination of radioactive metal surfaces  

DOEpatents

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.

Bray, Lane A. (Richland, WA)

1996-01-01

273

Fastener Tightening in a Radioactive (Hot) Cell.  

National Technical Information Service (NTIS)

Accurate remote tightening of fasteners in a radioactive (Hot) cell can be a very exasperating experience. Viewing can be difficult (in many places) and work sometimes must be done using mirrors and/or cameras. If electro mechanical manipulators are used,...

J. J. Kalk

1986-01-01

274

Ion beam analysis of radioactive samples  

NASA Astrophysics Data System (ADS)

The nuclear microprobe facility of the Pierre Süe 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.

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

2009-06-01

275

Hazardous chemical and radioactive wastes at Hanford  

SciTech Connect

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.

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

1991-07-01

276

Hazardous chemical and radioactive wastes at Hanford  

SciTech Connect

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.

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

1991-07-01

277

Safe transport of radioactive materials in Egypt  

NASA Astrophysics Data System (ADS)

In Egypt the national regulations for safe transport of radioactive materials (RAM) are based on the International Atomic Energy Agency (IAEA) regulations. In addition, regulations for the safe transport of these materials through the Suez Canal (SC) were laid down by the Egyptian Atomic Energy Authority (EAEA) and the Suez Canal Authority (SCA). They are continuously updated to meet the increased knowledge and the gained experience. The technical and protective measures taken during transport of RAM through SC are mentioned. Assessment of the impact of transporting radioactive materials through the Suez Canal using the INTERTRAN computer code was carried out in cooperation with IAEA. The transported activities and empty containers, the number of vessels carrying RAM through the canal from 1963 to 1991 and their nationalities are also discussed. The protective measures are mentioned.A review of the present situation of the radioactive wastes storage facilities at the Atomic Energy site at Inshas is given along with the regulation for safe transportation and disposal of radioactive wastes

El-Shinawy, Rifaat M. K.

1994-07-01

278

Thermostable Two-Channel Radioactivity Logging Apparatus.  

National Technical Information Service (NTIS)

A thermostable two-channel radioactivity logging (RL) apparatus, designed to operate at temperatures up to 220 exp 0 C and a hydrostatic pressure up to 1200 kgf/cm exp 2, developed and produced for conducting operations by the gamma logging (GL) and neutr...

E. S. Bakhromi M. V. Posikera

1976-01-01

279

Radioactive Acid Digestion Test Unit (RADTU), 1980  

Microsoft Academic Search

The Radioactive Acid Digestion Test Unit (RADTU) was constructed at the Hanford Site, Richland, WA to demonstrate application of the acid digestion process for treating combustible transuranic wastes and scrap materials. Using its original tray digester vessel, RADTU recently completed a six-month campaign of processing potentially contaminated non-glovebox wastes from a Hanford plutonium facility. During the campaign, 2100 kg of

1980-01-01

280

Canister arrangement for storing radioactive waste  

DOEpatents

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.

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

1980-04-23

281

The ORNL Radioactive Ion Beam Project  

Microsoft Academic Search

On June 30, 1992, the Holifield Heavy Ion Research Facility (HHIRF) was shut down as an operating national users' facility for heavy ion physics research and became a construction project to reconfigure the existing accelerator system and develop a first generation radioactive ion beam (RIB) facility. During its 11 years of operation, the HHIRF had over 600 users, of which

D. K. Olsen; G. D. Alton; R. L. Auble; C. Baktash; D. T. Dowling; J. D. Garrett; D. L. Haynes; C. M. Jones; R. C. Juras; M. J. Meigs; G. D. Mills; S. W. Mosko; R. L. Robinson; B. A. Tatum; H. Blosser; L. Lee; F. Marti; H. K. Carter; J. Kormicki; P. Mantica; L. Rayburn; C. A. Reed

1992-01-01

282

The ORNL Radioactive Ion Beam Project  

Microsoft Academic Search

On June 30, 1992, the Holifield Heavy Ion Research Facility (HHIRF) was shut down as an operating national users` facility for heavy ion physics research and became a construction project to reconfigure the existing accelerator system and develop a first generation radioactive ion beam (RIB) facility. During its 11 years of operation, the HHIRF had over 600 users, of which

D. K. Olsen; G. D. Alton; R. L. Auble; C. Baktash; D. T. Dowling; J. D. Garrett; D. L. Haynes; C. M. Jones; R. C. Juras; M. J. Meigs; G. D. Mills; S. W. Mosko; R. L. Robinson; B. A. Tatum; H. Blosser; L. Lee; F. Marti; H. K. Carter; J. Kormicki; P. Mantica; L. Rayburn; C. A. Reed; J. Dellwo; H. Wollnik

1992-01-01

283

Indirect estimation of radioactivity in containerized cargo  

Microsoft Academic Search

Naturally occurring radioactive material in containerized cargo challenges the state of the art in national and international efforts to detect illicit nuclear and radiological material in transported containers. Current systems are being evaluated and new systems envisioned to provide the high probability of detection necessary to thwart potential threats, combined with extremely low nuisance and false alarm rates necessary to

Kenneth D. Jarman; Chad Scherrer; L. E. Smith; Lawrence Chilton; K. K. Anderson; Jennifer J. Ressler; Lynn L. Trease

2011-01-01

284

Evaluation of radioactive scrap metal recycling  

Microsoft Academic Search

This report evaluates the human health risks and environmental and socio-political impacts of options for recycling radioactive scrap metal (RSM) or disposing of and replacing it. Argonne National Laboratory (ANL) is assisting the US Department of Energy (DOE), Office of Environmental Restoration and Waste Management, Oak Ridge Programs Division, in assessing the implications of RSM management alternatives. This study is

L. A. Nieves; S. Y. Chen; E. J. Kohout; B. Nabelssi; R. W. Tilbrook; S. E. Wilson

1995-01-01

285

Environmental Assessment Radioactive Source Recovery Program.  

National Technical Information Service (NTIS)

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 Environmental Assessment (EA) analyzes the po...

1995-01-01

286

Safety Aspects in Radioactive Waste Management  

Microsoft Academic Search

Bezpe?nostné aspekty mana?mentu rádioaktívneho odpadu In recent years, within the framework of national as well as international programmes, notable advances and considerable experience have been reached, particularly in minimising of the production of radioactive wastes, conditioning and disposal of short- lived, low and intermediate level waste, vitrification of fission product solutions on an industrial scale and engineered storage of long-

Peter W. Brennecke

287

Introduction to naturally occurring radioactive material.  

National Technical Information Service (NTIS)

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 f...

P. Egidi

1997-01-01

288

Introduction to naturally occurring radioactive material  

Microsoft Academic Search

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

Egidi

1997-01-01

289

Annual radioactive waste tank inspection program: 1995  

Microsoft Academic Search

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

McNatt; F. G. Sr

1996-01-01

290

Annual radioactive waste tank inspection program - 1996  

Microsoft Academic Search

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.

McNatt

1997-01-01

291

Lithium in RadioActive Minerals  

Microsoft Academic Search

THE recent results of Mile. Gleditsch (Comptes rendus, cxlvi., p. 331) corroborating those of Prof. McCoy, viz. that lithium is generally, but not always, a constituent of radio-active minerals containing copper, and that there is no fixed proportionality between the copper and the lithium in these minerals, must not be taken to have the exclusive significance which their authors attribute

W. Ramsay

1908-01-01

292

DETERMINATION OF RADIOACTIVITY IN SALINE WATERS  

Microsoft Academic Search

A screening method for the determination of gross radioactivity in ; saline waters is based on the precipitation of many cations as sulfides from ; ammoniacal solution. Carrier lanthanum, iron(III), cobalt(II), zinc, and nickel ; are precipitated while the major sea water salts are left in solution. An ; alkaline earth fraction containing strontium, barium, and radium can be recovered

V. J. Sodd; A. S. Goldin; R. J. Velten

1960-01-01

293

Residual radioactive material guidelines: Methodology and applications  

Microsoft Academic Search

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

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

1989-01-01

294

Radioactive scrap metal decontamination technology assessment report.  

National Technical Information Service (NTIS)

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 mate...

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

1996-01-01

295

Method for decontamination of radioactive metal surfaces  

DOEpatents

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.

Bray, L.A.

1996-08-13

296

Annual Radioactive Waste Tank Inspection Program - 1998  

SciTech Connect

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.

McNatt, F.G.

1999-10-27

297

Radioactive contamination incidents involving protective clothing  

Microsoft Academic Search

The study focuses on incidents at Department of Energy facilities involving the migration of radioactive contaminants through protective clothing. The authors analyzed 68 occurrence reports for the following factors: (1) type of work, (2) working conditions, (3) type of anti-contamination material; (4) area of body or clothing contaminated; and (5) nature of spread of contamination. A majority of reports identified

Richard A. Reichelt; Marc E. Clay; A. Jeffery Eichorst

1998-01-01

298

Radioactive contamination incidents involving protective clothing  

Microsoft Academic Search

The study focuses on incidents at Department of Energy (DOE) facilities involving the migration of radioactive contaminants through protective clothing. The authors analyzed 68 occurrence reports for the following factors: (1) type of work; (2) working conditions; (3) type of anti-contamination (anti-C) material; (4) area of body or clothing contaminated; and (5) nature of spread of contamination. A majority of

R. Reichelt; M. Clay; J. Eichorst

1996-01-01

299

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...

300

Annual radioactive waste tank inspection program - 1999  

SciTech Connect

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.

Moore, C.J.

2000-04-14

301

Annual Radioactive Waste Tank Inspection Program 1994  

SciTech Connect

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.

McNatt, F.G. Sr.

1995-04-01

302

Annual Radioactive Waste Tank Inspection Program - 1997  

SciTech Connect

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.

McNatt, F.G. [Westinghouse Savannah River Company, AIKEN, SC (United States)

1998-05-01

303

Annual radioactive waste tank inspection program: 1995  

SciTech Connect

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

McNatt, F.G. Sr.

1996-04-01

304

Annual radioactive waste tank inspection program - 1996  

SciTech Connect

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.

McNatt, F.G.

1997-04-01

305

Confinement Chamber for Radioactive Products or Waste.  

National Technical Information Service (NTIS)

The invention deals with a confinement chamber for radioactive products or wastes that are kept in tanks or in silos buried in the ground. The chamber comprises a combination of an impervious reinforced concrete (RC) support buried in the ground with an R...

1977-01-01

306

[Loss and uncontrolled use of radioactive sources].  

PubMed

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

Govaerts, P

2005-01-01

307

Notes on Incineration of Radioactive Waste.  

National Technical Information Service (NTIS)

The problem of finding commercial sites for the disposal of low-level radioactive waste and temporary storage of residues containing transuranic elements has led to research on using a method to reduce the volume of the waste originating from nuclear inst...

L. M. Martin

1984-01-01

308

Artificial Radioactivity Reference Horizons in Greenland Firn.  

National Technical Information Service (NTIS)

Total beta measurements have been made on melt water samples from a stratigraphically dated firn core profile from the inland Greenland ice sheet (77 deg 10 min N, 61 deg 08 min W). A marked increase in radioactivity is found in the 1953 firn layer which ...

G. Crozaz C. C. Langway E. Picciotto

1966-01-01

309

Review: Radioactive Microspheres for Medical Applications  

Microsoft Academic Search

Summary This paper reviews the preparation and application of radioactive microspheres for medical purposes. It first discusses the properties of relevant radioisotopes and then explores the diagnostic uses of gamma- emitter labeled microspheres, such as blood flow measurement and imaging of the liver and other organs. The therapeutic uses of alpha- and beta-emitting microspheres, such as radioembolization, local tumor therapy

Urs Häfeli

310

Geochemical behavior of disposed radioactive waste  

Microsoft Academic Search

This book examines the complex issue of radioactive waste disposal and the health hazards at underground waste sites. It assesses the chemical and physical behavior of wastes from the nuclear fuel cycle, from nuclear weapons testing, and from medical and research activities. It also reports recent findings in this area and looks at ongoing research.

G. S. Barney; W. W. Schulz; J. D. Navratil

1984-01-01

311

Management of Radioactive Waste and Plutonium in the Swedish Perspective.  

National Technical Information Service (NTIS)

In May 1976 the Governmental Committee on Radioactive Waste (the Aka Committee) submitted its final report to the Swedish Government. The report summarizes a thorough investigation of questions dealing with spent nuclear fuel and radioactive waste. For Sw...

A. Larsson A. Hultgren J. Lind

1977-01-01

312

Consortium seeks solution for low-level radioactive steel  

Microsoft Academic Search

Idaho National Engineering Laboratory has begun testing an innovative radioactive scrap metal recycling program that could reduce utilities radioactive waste disposal costs significantly by allowing them to turn irradiated crap metal from decommissioned nuclear plants into spent fuel canisters.

1994-01-01

313

Postaccident cleanup analysis for transportation of radioactive materials.  

National Technical Information Service (NTIS)

Approximately 5 to 10 million packages of radioactive material and wastes are shipped annually in the US. Most of these shipments consist of small quantities of medical and research isotopes. However, larger quantities of radioactive wastes are shipped by...

S. Y. Chen B. M. Biwer

1998-01-01

314

Radioactive waste disposal assessment - overview of biosphere processes and models.  

National Technical Information Service (NTIS)

This report provides an overview of biosphere processes and models in the general context of the radiological assessment of radioactive waste disposal as a basis for HMIP's response to biosphere aspects of Nirex's submissions for disposal of radioactive w...

P. J. Coughtrey

1992-01-01

315

Centralized Collection of Radioactive Wastes. Terms and Definitions.  

National Technical Information Service (NTIS)

The standard is based upon the regulation concerning the centralized collection and storage of radioactive wastes of 11 May 1981 and specifies the practical conditions and interactions during collection, transport, storage, and disposal of radioactive was...

1985-01-01

316

Exploring solid state physics properties with radioactive isotopes  

Microsoft Academic Search

Radioactive atoms have been used in solid state physics for many years. Established nuclear techniques such as Mbauer spectroscopy, perturbed angular correlation, -NMR and emission channelling have now been joined by new and successful tracer techniques like radioactive deep level transient spectroscopy, capacitance voltage measurements, Hall-effect measurements or photoluminescence spectroscopy. Numerous radioactive species, ranging from to , are employed to

Doris Forkel-Wirth

1999-01-01

317

Controlled Containment, Radioactive Waste Management in the Netherlands  

Microsoft Academic Search

All radioactive waste produced in The Netherlands is managed by COVRA, the central organization for radioactive waste. The Netherlands forms a good example of a country with a small nuclear power program which will end in the near future. However, radioisotope production, nuclear research and other industrial activities will continue to produce radioactive waste. For the small volume, but broad

Codee

2002-01-01

318

Naturally occurring radioactive materials and medical isotopes at border crossings  

Microsoft Academic Search

Countries around the world are deploying radiation detection instrumentation to interdict the illegal shipment of radioactive material crossing international borders. Some cargo contains naturally occurring radioactive material (NORM) or technologically enhanced NORM (TENORM) that triggers alarms at border crossings. This paper discusses experience with radiation portal monitors for the interdiction of radioactive materials and the issues raised by NORM. The

R. T. Kouzes; J. H. Ely; B. D. Geelhood; R. R. Hansen; E. A. Lepel; J. E. Schweppe; L. Siciliano; R. A. Warner

2003-01-01

319

49 CFR 172.436 - RADIOACTIVE WHITE-I label.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false RADIOACTIVE WHITE-I label. 172.436 Section 172... Labeling § 172.436 RADIOACTIVE WHITE-I label. (a) Except for size and color, the RADIOACTIVE WHITE-I label must be as follows:...

2013-10-01

320

RADIATION PROTECTION IN ASSOCIATION WITH BARE RADIOACTIVE MATERIALS. PART II  

Microsoft Academic Search

A description is given of the measures of organization necessary for ; safe handling of radioactive material and the methods for supervising the hazards ; of contamination. Furthermore, radioactive decontamination and removal of ; radioactive waste are briefly referred to. An annexal survey of different types ; of laboratories demonstrates the methods of furnishing these places in regard of ;

Gotte

1960-01-01

321

RADIATION PROTECTION IN HANDLING UNSEALED RADIOACTIVE MATERIALS. PART I  

Microsoft Academic Search

The conception of a radioactive contamination is explained and the ; hazards are estimated which may result from the uncontrolled spreading of ; radioactive material. Moreover, measures are described to prevent uncontrolled ; contamination and indications are made on how to handle radioactive materials in ; chemical laboratories. (auth);

Gotte

1960-01-01

322

Radioactive waste management at a large university medical research complex  

Microsoft Academic Search

This report describes radioactive waste management at Harvard University. To contain costs and to reduce the impact of the low-level radioactive waste policy act, the program takes advantage of decay in storage, incineration, special packaging techniques, and increased training and awareness. A series of metrics, numerical ratios, are presented to evaluate the effectiveness of the radioactive waste management program. Through

J. Ring; F. Osborne; W. Lorenzen

1995-01-01

323

Review of physics, instrumentation and dosimetry of radioactive isotopes  

NASA Technical Reports Server (NTRS)

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.

Sinclair, W. K.

1967-01-01

324

10 CFR 61.41 - Protection of the general population from releases of radioactivity.  

Code of Federal Regulations, 2010 CFR

...general population from releases of radioactivity. 61.41 Section 61.41 Energy...general population from releases of radioactivity. Concentrations of radioactive...should be made to maintain releases of radioactivity in effluents to the general...

2009-01-01

325

10 CFR 61.41 - Protection of the general population from releases of radioactivity.  

Code of Federal Regulations, 2010 CFR

...general population from releases of radioactivity. 61.41 Section 61.41 Energy...general population from releases of radioactivity. Concentrations of radioactive...should be made to maintain releases of radioactivity in effluents to the general...

2010-01-01

326

Integrating natural and social sciences to inspire public confidence in radioactive waste policy case study - Committee on radioactive waste management  

Microsoft Academic Search

Integrating Natural and Social Sciences to Inspire Public Confidence in Radioactive Waste Policy Case Study: Committee on Radioactive Waste Management Implementing effective long-term radioactive waste management policy is challenging, and both UK and international experience is littered with policy and programme failures. Policy must not only be underpinned by sound science and technical rationale, it must also inspire the confidence

Usher

2007-01-01

327

Volatile Transport and Accumulation Timescales Modeled using 210Pb226Ra Disequilibrium in Tephras From Mount Pinatubo Volcano, Philippines: Moving From the Timescales of 222Rn to 210Pb  

Microsoft Academic Search

We measured 210Pb-222Rn-226Ra disequilibria in samples representing a time sequence through the June 15, 1991 cataclysmic eruption tephras of Mount Pinatubo volcano, Philippines. Previous U- series degassing studies have interpreted 210Pb excess to indicate rapid volatile transport (differential 222Rn motion) and subsequent volatile accumulation. Mount Pinatubo deposits show evidence for volatile saturation and the presence of a pre-eruptive volatile phase.

T. M. Kayzar; K. M. Cooper; M. K. Reagan; A. J. Kent; V. C. Kress

2007-01-01

328

Commercial low-level radioactive waste transportation safety history  

SciTech Connect

An excellent safety record has been established for the transport of commercial low-level radioactive waste. By using the Radioactive Material Incident Report data base to evaluate transportation accidents involving commercial low-level radioactive waste, it was found that there have been only four transportation accidents involving the release of commercial low-level radioactive waste in the last 20 years. The accidents were minor, and the released materials were quickly repackaged. There has never been a radiologically related injury or death associated with a transportation accident involving commercial low-level radioactive waste.

Garcia, R.S.

1992-03-01

329

A Novel Radioactive Isotope Ion Target SCRIT  

SciTech Connect

Electron scattering is a superior method to investigate the internal structure, such as charge distribution, of atomic nuclei. Most of the radii of nuclei were determined unambiguously by that. However, radioactive isotopes (RI) which recently came up to a major research interest have not been accessible due to the difficulty in making fixed targets and taking measurements before they decay. We proposed a conceptually new target called SCRIT (Self-Confining Radioactive Isotope ion Target) as opposed to a collider method. The luminosity expected for SCRIT is inevitably low (typically on the order of 1.E+27/cm{sup 2}/s) and a large acceptance detector system is required. We plan to perform a coincidence measurement using an electron arm and a recoil ion detector which needs to be developed. Current status of the ion trapping with a prototype SCRIT and the background measurement results in an electron storage ring will be discussed.

Kurita, Kazuyoshi [Department of Physics, Rikkyo University, Nishi-Ikebukuro Toshima, Tokyo, 171-8501 (Japan); Cycltron Center, RIKEN, Wako, Saitama, 351-0198 (Japan); Masuda, Tetsuya [Department of Physics, Rikkyo University, Nishi-Ikebukuro Toshima, Tokyo, 171-8501 (Japan); Koseki, Tadashi [Accelerator Division I, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan); Noda, Akira; Shirai, Toshiyuki; Tongu, Hiromu [Center for Beam Science, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 (Japan); Furukawa, Yukihiro; Tamae, Tadaaki [Laboratory of Nuclear Science, Tohoku University, Mikamine, Taihaku, Sendai, 982-0826 (Japan); Ito, Sachiko; Emoto, Takashi; Nakamura, Masato; Wakasugi, Masanori; Yano, Yasushige [Cycltron Center, RIKEN, Wako, Saitama, 351-0198 (Japan); Ohnishi, Tetsuya; Suda, Toshimi; Takeda, Hiroyuki; Wang Shuo [RI Beam Science Laboratory, RIKEN, Wako, Saitama, 351-0198 (Japan)

2006-11-20

330

Proton radioactivity with a Yukawa effective interaction  

NASA Astrophysics Data System (ADS)

The half-lives of proton radioactivity of proton emitters are investigated theoretically. Proton-nucleus interaction potentials are obtained by folding the densities of the daughter nuclei with a finite-range effective nucleon-nucleon interaction having Yukawa form. The Wood-Saxon density distributions for the nuclei used in calculating the nuclear as well as the Coulomb interaction potentials are predictions of the interaction. The quantum mechanical tunneling probability is calculated within the WKB framework. These calculations provide reasonable estimates for the observed proton radioactivity lifetimes. The effects of neutron-proton effective mass splitting in neutron-rich asymmetric matter as well as the nuclear matter incompressibility on the decay probability are investigated.

Routray, T. R.; Tripathy, S. K.; Dash, B. B.; Behera, B.; Basu, D. N.

2011-08-01

331

Permanent disposal of radioactive particulate waste  

SciTech Connect

A system for storage and encapsulation of radioactive particulate waste, is described comprising: a cartridge having a liquid impervious casing enclosing a waster storage region, a ferromagnetic waste storage matrix housed in the cartridge and occupying at least a major portion of the waste storage region, and an inlet conduit and at least one outlet conduit projecting from the cartridge and communicating with the waste storage region; means for establishing a magnetic field in the matrix; fluid handling means including a source of liquid containing the radioactive waste to be stored in the cartridge, a source of encapsulating material, and a receptacle for receiving flushing water; cartridge filling means including conduits releasably couplable to the conduits associated with the cartridge; and fluid flow control means including remotely controllable valves connected between the fluid handling means and the cartridge filling means.

Troy, M.

1988-04-19

332

Radioactive targets for nuclear accelerator experiments  

NASA Astrophysics Data System (ADS)

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.

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

1991-05-01

333

Treatment of Radioactive Reactive Mixed Waste  

SciTech Connect

PacificEcoSolutions, Inc. (PEcoS) has installed a plasma gasification system that was recently modified and used to destroy a trimethyl-aluminum mixed waste stream from Los Alamos National Laboratory (LANL.) The unique challenge in handling reactive wastes like trimethyl-aluminum is their propensity to flame instantly on contact with air and to react violently with water. To safely address this issue, PacificEcoSolutions has developed a new feed system to ensure the safe containment of these radioactive reactive wastes during transfer to the gasification unit. The plasma gasification system safely processed the radioactively contaminated trimethyl-metal compounds into metal oxides. The waste stream came from LANL research operations, and had been in storage for seven years, pending treatment options. (authors)

Colby, S.; Turner, Z.; Utley, D. [Pacific EcoSolutions, Inc., 2025 Battelle Boulevard, Richland, Washington 99354 (United States); Duy, C. [Los Alamos National Laboratory - LA-UR-05-8410, Post Office Box 1663 MS J595, Los Alamos, New Mexico 97545 (United States)

2006-07-01

334

Airborne radioactivity surveys for phosphate in Florida  

USGS Publications Warehouse

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.

Moxham, Robert M.

1954-01-01

335

ORNL Radioactive Beams for Stellar Explosion Studies  

SciTech Connect

Thermonuclear reactions on unstable nuclei generate the energy that power nova explosions and X-ray bursts. In these explosions and others such as supernovae, these reactions serve to synthesize nuclei that (via their decay) can serve as tracers of the explosion mechanism. A powerful approach to improve our understanding of these explosions is to utilize beams of radioactive nuclei for direct and indirect measurements of these reactions. We are pursuing this approach at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory (ORNL) to study reactions in the rp-process (with beams of {sup 17,18}F) and the r-process (with beams of {sup 82}Ge, {sup 84}Se {sup 130,132}Sn, {sup 134}Te). These measurements are combined with synergistic data evaluations and element synthesis calculations. Highlights of recent results are presented.

Smith, Michael S. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831-6354 (United States)

2008-05-21

336

USDOE radioactive waste incineration technology: status review  

SciTech Connect

Early attempts were made to incinerate radioactive wastes met with operation and equipment problems such as feed preparation, corrosion, inadequate off-gas cleanup, incomplete combustion, and isotope containment. The US Department of Energy (DOE) continues to sponsor research, development, and the eventual demonstration of radioactive waste incineration. In addition, several industries are developing proprietary incineration system designs to meet other specific radwaste processing requirements. Although development efforts continue, significant results are available for the nuclear community and the general public to draw on in planning. This paper presents an introduction to incineration concerns, and an overview of the prominent radwaste incineration processes being developed within DOE. Brief process descriptions, status and goals of individual incineration systems, and planned or potential applications are also included.

Borduin, L.C.; Taboas, A.L.

1980-01-01

337

Radioactive scrap metal decontamination technology assessment report  

SciTech Connect

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.

Buckentin, J.M.; Damkroger, B.K.; Schlienger, M.E. [Sandia National Labs., Albuquerque, NM (United States). Liquid Metal Processing Lab.

1996-04-01

338

Two-proton radioactivity of 45Fe  

SciTech Connect

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.

Miernik, K. [University of Warsaw; Dominik, W. [University of Warsaw; Janas, Z. [University of Warsaw; Pfutzner, M. [University of Warsaw; Grigorenko, L. [Joint Institute for Nuclear Research, Dubna, Russia; Bingham, C. R. [University of Tennessee, Knoxville (UTK); Czyrkowski, H. [University of Warsaw; Cwiok, Mikolaj [Warsaw University; Darby, Iain [University of Tennessee, Knoxville (UTK); Dabrowski, Ryszard [Warsaw University; Ginter, T. N. [Michigan State University, East Lansing; Grzywacz, R. [University of Tennessee, Knoxville (UTK); Karny, M. [University of Warsaw; Korgul, A. [University of Warsaw; Kusmierz, W. [University of Warsaw; Liddick, Sean [University of Tennessee, Knoxville (UTK); Rajabali, Mustafa [University of Tennessee, Knoxville (UTK); Rykaczewski, Krzysztof Piotr [ORNL; Stolz, A. [Michigan State University, East Lansing

2009-01-01

339

Handbook of high-level radioactive waste transportation  

SciTech Connect

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.

Sattler, L.R.

1992-10-01

340

Fabrication of radioactive stents by ion implantation  

NASA Astrophysics Data System (ADS)

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.

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

2002-02-01

341

Radioactive fuel cask railcar humping study  

Microsoft Academic Search

The response of two radioactive shipping casks due to railroad humping shocks was calculated using a spring-mass model. The two railcars for these casks had different coupling mechanisms and different tiedown arrangements. Humping tests had been performed on one of the railcars (ATMX-600) and the resulting shock spectra was used to adjust the spring-mass model to get matching results. One

1978-01-01

342

Assessment of environmental radioactivity for Batman, Turkey  

Microsoft Academic Search

The province of Batman, located in southern Anatolia, has a population of approximately 500,000. To our knowledge, there exists\\u000a no information regarding the environmental radioactivity in this province. Therefore, gamma activity measurements in soil,\\u000a building materials and water samples and an indoor radon survey have been carried out in the Batman province. The mean activity\\u000a concentrations of the natural radionuclides

Nevzat Damla; Ugur Cevik; Ali Ihsan Kobya; Berna Ataksor; Umit Is?k

2010-01-01

343

Radioactive isotopes in solid state physics  

Microsoft Academic Search

A wide range of solid state physics techniques is using radioactive ion beams, both from on-line and off-line separators. The different techniques can be roughly subdivided into two classes: one, including the hyperfine techniques like Mößbauer spectroscopy (MS), Perturbed Angular Correlation (PAC) spectroscopy, beta-NMR and the ion-beam technique of Emission Channeling (EC). They all crucially depend on the availability of

D. Forkel-Wirth

1996-01-01

344

Radioactive isotopes in solid state physics  

Microsoft Academic Search

A wide range of solid state physics techniques is using radioactive ion beams, both from on-line and off-line separators. The different techniques can be roughly subdivided into two classes: one, including the hyperfine techniques like Mößbauer spectroscopy (MS), Perturbed Angular Correlation (PAC) spectroscopy, ?-NMR and the ion-beam technique of Emission Channeling (EC). They all crucially depend on the availability of

Doris Forkel-Wirth

1997-01-01

345

Recycling radioactively contaminated materials: Experience and prognosis  

Microsoft Academic Search

In recent years, federal agencies, especially the U.S. Department of Energy (DOE), the U.S. Department of Defense (DOD), the U.S. Environmental Protection Agency, and the U.S. Nuclear Regulatory Commission (NRC), as well as the commercial nuclear enterprise, have begun to consider certain radioactively contaminated materials as resources for beneficial reuse rather than wastes. Most outstanding among these materials is metal

D. E. Large; H. W. Arrowsmith

1993-01-01

346

Radioactive-ion-beam research at Livermore  

NASA Astrophysics Data System (ADS)

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.

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

1983-06-01

347

Radioactive contamination of the Yenisei River  

Microsoft Academic Search

Based on observational data in the period 1971–1993, radioactive contamination of the Yenisei River ecosystem was analysed within 2000 km of the site of discharges from the Krasnoyarsk Mining and Chemical Industrial Complex. Data on the content of 24Na, 32P, 46Sc, 51Cr, 54Mn, 56Mn, 58Co, 60Co, 59Fe, 65Zn, 90Sr, 95Zr, 95Nb, 103Ru, 106Ru, 134Cs, 137Cs, 140Ba, 141Ce, 144Ce and 239Np

E. G. Tertyshnik

1995-01-01

348

Electrically Driven Technologies for Radioactive Aerosol Abatement  

SciTech Connect

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.

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

2003-01-28

349

Phosphate bonded solidification of radioactive incinerator wastes  

SciTech Connect

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.

Walker, B. W.; Langton, C. A.; Singh, D.

1999-12-03

350

Transport of Carbon Dioxide and Radioactive Waste  

Microsoft Academic Search

\\u000a A comparative assessment of carbon dioxide (CO2) and radioactive waste transport systems associated with electricity generation was undertaken on the basis of 15 criteria\\u000a grouped under three areas, namely the transport chain, policy aspects and state of the technology. For CO2, we considered exclusively the transport that would take place under a future large-scale capture and storage infrastructure.\\u000a Our study

Darío R. Gómez; Michael Tyacke

351

Natural radioactivity levels in Andalusian spas  

Microsoft Academic Search

Gross-? and gross-? activity, 222Rn, 226Ra and 224Ra of waters from several spas of Andalusia (Spain) were performed in order to determine their radioactivity. Radon concentration ranged from 0.225 to 130Bq\\/l. 226Ra and 224Ra concentrations ranged from 2 to 1367mBq\\/l and from 2 to 122mBq\\/l respectively. Correlations between the 222Rn and 226Ra concentrations and gross-? activity were obtained. A correlation

C Dueñas; M. C Fernández; C Enr??quez; J Carretero; E Liger

1998-01-01

352

Radioactive Particles Released from Different Nuclear Sources  

Microsoft Academic Search

Following releases from severe nuclear events such as nuclear weapon tests, use of depleted uranium ammunition and reactor\\u000a explosions or fire, a major fraction of refractory radionuclides such as uranium (U) and plutonium (Pu) is present as particles,\\u000a often ranging from submicrons to fragments. Radioactive particles and colloids are also released via effluents from reprocessing\\u000a facilities and civil reactors, and

Brit Salbu

353

Radioactive iodine therapy in cats with hyperthyroidism.  

PubMed

Eleven cats with hyperthyroidism were treated with radioactive iodine (131I). 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 131I administered was calculated from peak RAIU, effective half-life, and estimated thyroid gland weight. Activity of 131I 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 131I ablation of thyroid tumors was a reasonable alternative in the treatment of hyperthyroidism in cats. The optimal method of dosimetry remains to be determined. PMID:6706799

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

1984-03-01

354

Radioactive waste management in the former USSR  

SciTech Connect

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.

Bradley, D.J.

1992-06-01

355

Radioactive iodine therapy in cats with hyperthyroidism  

SciTech Connect

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.

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

1984-03-01

356

Scrap metals industry perspective on radioactive materials.  

PubMed

With more than 80 reported/confirmed accidental melts worldwide since 1983 and still counting, potential contamination by radioactive materials remains as a major concern among recycled scrap and steel companies. Some of these events were catastrophic and have cost the industry millions of dollars in business and, at the same time, resulted in declining consumer confidence. It is also known that more events with confirmed radioactive contamination have occurred that involve mining of old steel slag and skull dumps. Consequently, the steel industry has since undergone massive changes that incurred unprecedented expenses through the installation of radiation monitoring systems in hopes of preventing another accidental melt. Despite such extraordinary efforts, accidental melts continue to occur and plague the industry. One recent reported/confirmed event occurred in the Republic of China in 2004, causing the usual lengthy shutdown for expensive decontamination efforts before the steel mill could resume operations. With this perspective in mind, the metal industry has a long-standing opposition to the release of radioactive materials of any kind to commerce for fear of contamination and the potential consequences. PMID:17033460

Turner, Ray

2006-11-01

357

RESRAD. Site-Specific Residual Radioactivity  

SciTech Connect

RESRAD is designed to derive site-specific guidelines for allowable residual concentrations of radionuclides in soil. A guideline is defined as a radionuclide concentration or a level of radiation or radioactivity that is acceptable if a site is to be used without radiological restrictions. Guidelines are expressed as (1) concentrations of residual radionuclides in soil, (2) concentrations of airborne radon decay products, (3) levels of external gamma radiation, (4) levels of radioactivity from surface contamination, and (5) concentrations of residual radionuclides in air and water. Soil is defined as unconsolidated earth material, including rubble and debris that may be present. The controlling principles of all guidelines are (1) the annual radiation dose received by a member of the critical population group from the residual radioactive material - predicted by a realistic but reasonably conservative analysis and averaged over a 50 year period - should not exceed 100 mrem/yr, and (2) doses should be kept as low as reasonably achievable. All significant exposure pathways for the critical population group are considered in deriving soil guidelines. These pathways include direct exposure to external radiation from the contaminated soil material; internal radiation from inhalation of airborne radionuclides; and internal radiation from ingestion of plant foods grown in the contaminated soil, meat and milk from livestock fed with contaminated fodder and water, drinking water from a contaminated well, and fish from a contaminated pond.

Yu, C. [Argonne National Laboratory, IL (United States)

1989-06-01

358

Sources of Radioactive Isotopes for Dirty Bombs  

NASA Astrophysics Data System (ADS)

From the security perspective, radioisotopes and radioactive sources are not created equal. Of the many radioisotopes used in industrial applications, medical treatments, and scientific research, only eight, when present in relatively large amounts in radioactive sources, pose high security risks primarily because of their prevalence and physical properties. These isotopes are americium-241, californium-252, cesium-137, cobalt-60, iridium-192, radium-226, plutonium-238, and strontium-90. Except for the naturally occurring radium-226, nuclear reactors produce the other seven in bulk commercial quantities. Half of these isotopes emit alpha radiation and would, thus, primarily pose internal threats to health; the others are mainly high-energy gamma emitters and would present both external and internal health hazards. Therefore, the response to a "dirty bomb" event depends on what type of radioisotope is chosen and how it is employed. While only a handful of major corporations produce the reactor-generated radioisotopes, they market these materials to thousands of smaller companies and users throughout the world. Improving the security of the high-risk radioactive sources will require, among other efforts, cooperation among source suppliers and regulatory agencies.

Lubenau, Joel

2004-05-01

359

BIOPROTA: an international forum for environmental modelling in support of long-term radioactive waste management  

SciTech Connect

An international Forum, BIOPROTA, has been set up and maintained which allows common long-term environmental radiological assessment problems, such as post-closure modelling studies to be identified and then addressed. The focus of the Forum is to address key uncertainties in environmental modelling and related dose assessment with special reference to evaluation of the long-term impact of contaminant releases associated with radioactive waste management. The application of shared resources results in effective resource management and the development of common solutions to common problems. The Forum began in 2002 and has benefited from the knowledge and experience of organisations from Belgium (SCK.CEN), Czech Republic (NRI), Canada (OPG), Finland (Posiva), France (ANDRA, EdF), Japan (NUMO), Korea (KAERI), Norway (NRPA), Spain (ENRESA, CIEMAT), Sweden (SKB, SSI), Switzerland (Nagra), UK (Nirex, Nexia, UKAEA) and the USA (EPRI). These organisations include a mixture of operators, regulators and research institutes, and hence, including the participation of their technical support organizations, constitutes a very broad-based Forum. Enviros has acted as the technical secretariat to the Forum since its formation. Initially the Forum focused on three themes aimed at advancing knowledge and improving model predictions relating to performance and safety assessments: Theme 1 Development of a database to meet the key biosphere assessment information deficiencies. Theme 2 Implementation of a series of tasks to address key modelling issues, including uncertainties and inconsistencies in the modelling of inhalation, irrigation and soil contamination dose pathways; and approaches to the modelling the transfer of radionuclides across the geosphere-biosphere interface zone (GBIZ). Theme 3 Provision of guidance on site characterisation and experimental and monitoring protocols relevant to improving confidence in the biosphere component of the overall performance assessment. Substantial work under Themes 2 and 3 was completed in 2005/06 resulting in the publication of a variety of reports and guidance documents. Results of the model comparisons conducted under Theme 2 suggest that we can be confident in model structures and we have gained knowledge of the sensitive assumptions. Population of the database produced under Theme 1 is ongoing after release of an initial version which focused on data for Cl-36, Se-79, Tc-99, I-129, Np-237 and U-series radionuclides. In 2006, BIOPROTA received further international interest. The 2006 annual workshop identified a series of current issues for which proposals for tasks aimed at addressing these issues are under development. This includes exchange of information on models and processes of relevance to Cl-36 behaviour, as well as modelling the disequilibrium in the U-238 decay chain in environmental systems; more precise understanding of released C-14 distribution within various environmental carbon pools; and studies of the GBIZ under environmental change. A special workshop was held on Cl-36 behaviour and the workshop report published. An overview of the current state of play in biosphere modeling and dose assessment programmes relating to radioactive waste management will be presented based on national presentations by Forum members at the 2007 workshop and the key research outputs developed through the Forum will be described. (authors)

Smith, K.L.; Smith, G. [Enviros Consulting Ltd, D5 Culham Science Centre, Abingdon, OX (United Kingdom); Laciok, A. [Nuclear Research Institute, CZ-25068 REZ (Costa Rica)

2007-07-01

360

Soils: man-caused radioactivity and radiation forecast  

SciTech Connect

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)

Gablin, Vassily [Scientific-Industrial Association 'Radon', 7th Rostovsky Lane, Moscow 119121 (Russian Federation)

2007-07-01

361

Radioactive waste storage and disposal in the UK  

SciTech Connect

Even though mankind has evolved in a naturally radioactive environment, the existence of radiation was only discovered about a century or so ago. Since then the use of radioactive materials has grown rapidly and they are now used extensively in hospitals for medical diagnosis and treatment, and in general industry where they are used for measurement and inspection, as well as by the nuclear power industry, research laboratories and defence establishments. Like virtually all of man`s activities, the use of radioactive materials inevitably leads to the production of unwanted waste by-products, some of which will be radioactive. These radioactive wastes can be found in many different solid, liquid or gaseous forms and the radioactivity can range from such low levels that it is radiologically insignificant to levels that could cause death on direct exposure to it. To give a general indication of the levels of radioactivity, the wastes in the UK are usually grouped into three broad categories: (1) Low level waste (LLW): the least radioactive category; (2) Intermediate level waste (ILW); (3) High level waste (HLW): the most radioactive category. This waste is so highly radioactive that it generates significant quantities of heat and it is therefore also sometimes referred to as Heat Generating Waste. Radioactive wastes are produced by many industries in the UK although the majority both in terms of volume and radioactivity content comes from the civil nuclear power industry. This chapter concentrates on describing the way solid radioactive wastes are managed by the UK nuclear industry, within the Governments`s overall policy framework. It includes a description of the types and quantities of waste to be managed, current practices including the disposal of LLW, and plans for a deep repository for both ILW and LLW. 12 refs., 7 figs., 2 tabs.

Johnson, A.D.; Maul, P.R.; Passant, F.H. [Central Electricity Generating Board, Gloucester (United Kingdom)

1990-12-31

362

Estimation of monosaccharide radioactivity in biological samples through osazone derivatization  

SciTech Connect

A method for the quantitative estimation of radioactivity in the glucose (monosaccharide) fraction of biological samples is presented. Radioactive samples are added with cold glucose, and 1 aliquot receives a known amount of radioactive glucose as internal standard. After controlled osazone formation and three washings of the yellow precipitate, the osazones are dissolved, decolored, and their radioactivity determined through scintillation counting. The overall efficiency of recovery is 23-24% of the initial readioactivity. Each sample is corrected by the recovery of its own internal standard. There is a very close linear relationship between radioactivity present in the samples and radioactivity found, despite the use of different biological samples (rat plasma, hen egg yolk and albumen).

Garcia, F.J.; Pons, A.; Alemany, M.; Palou, A.

1982-03-01

363

World new facilities for radioactive isotope beams  

NASA Astrophysics Data System (ADS)

The use of unstable nuclei in the form of energetic beams for nuclear physics studies is now entering into a new era. "New-generation" facilities are either in operation, under construction or being planned. They are designed to provide radioactive isotope (RI) beams with very high intensities over a wide range of nuclides. These facilities are expected to provide opportunities to study nuclear structure, astrophysical nuclear processes and nuclear matter with large proton-neutron imbalance in grate detail. This article reports on the current status of such new-generation RI-beam facilities around the world.

Motobayashi, Tohru

2014-03-01

364

Particle beam generator using a radioactive source  

DOEpatents

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.

Underwood, David G. (Naperville, IL)

1993-01-01

365

Geologic disposal of radioactive waste, 1983  

SciTech Connect

Geologic repositories for radioactive waste are evolving from conceptualization to the development of specific designs. Estimates of long-term hazards must be based upon quantitative predictions of environmental releases over time periods of hundreds of thousands of years and longer. This paper summarizes new techniques for predicting the long-term performance of repositories, it presents estimates of future environmental releases and radiation doses that may result for conceptual repositories in various geologic media, and it compares these predictions with an individual dose criterion of 10{sup -4} Sv/y. 50 references, 11 figures, 6 tables.

Pigford, T.H.

1983-10-01

366

Hanford Site radioactive hazardous materials packaging directory  

SciTech Connect

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.

McCarthy, T.L.

1995-12-01

367

Corrosion resistant storage container for radioactive material  

DOEpatents

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.

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

1984-08-30

368

Corrosion resistant storage container for radioactive material  

DOEpatents

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.

Schweitzer, Donald G. (Bayport, NY) [Bayport, NY; Davis, Mary S. (Wading River, NY) [Wading River, NY

1990-01-01

369

Recycling and reuse of radioactive materials  

NASA Astrophysics Data System (ADS)

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 program capable of turning out graduates that have an understanding of contamination and dose control techniques that complement their knowledge of the elements that they work with. The Program has also adopted a radionuclide recovery and reuse program that has provided materials from other universities, government agencies, and private companies for use in experiments.

O'Dou, Thomas Joseph

370

Some Perspectives on Future Proton Radioactivity Experiments  

SciTech Connect

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.

Page, R. D. [Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, L69 7ZE (United Kingdom)

2011-11-30

371

Particle beam generator using a radioactive source  

DOEpatents

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.

Underwood, D.G.

1993-03-30

372

Gamma emitting radioactive materials in household dinnerware  

NASA Astrophysics Data System (ADS)

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.

Khalil, Fawzia Ahmad

373

Cracking of cumene on a radioactive tricalcium phosphate catalyst  

Microsoft Academic Search

1.The action of radioactive tricalcium phosphate catalysts containing the isotopes Ca45 and P32 in the cracking of cumene was investigated.2.The cracking of cumene on radioactive tricalcium phosphate catalysts is not acclerated in comparison with nonradioactive catalysts.3.The radioactivity of the catalysts, reaching 87 mCi\\/g, had no effect upon the nature and number of the acid centers of tricalcium phosphate, determined by

A. A. Balandin; Vikt I. Spitsyn; N. P. Dobrosel'skaya

1965-01-01

374

Geohazards due to technologically enhanced natural radioactive wastes  

Microsoft Academic Search

Human activities can modify naturally occurring radioactive material (NORM) into technologically enhanced naturally occurring\\u000a radioactive material (TENORM) as a result of industrial activities. Most of these industries do not intend to work with radioactive\\u000a material a priori. However, whenever a uranium- or thorium-bearing mineral is exploited, NORM-containing by-products and TENORM-contaminated\\u000a wastes are created. The industrial use of NORM can result

Friedrich Steinhäusler

2010-01-01

375

A radioactive target/ion source for material research  

NASA Astrophysics Data System (ADS)

A radioactive target/ion source for material research has been developed at China Institute of Atomic Energy, China. With a proton ion beam from the HI-13 tandem as the primary beam, the low intensity radioactive ion beam is generated on line. The first aim of the source is to produce a radioactive ion beam of 62Zn+ which will serve as nuclear probe in material research. The main features and current status of the source are presented in this article.

Cui, B.; Li, L.; Ma, Y.; Wang, R.; Jiang, W.

2004-05-01

376

Defense Waste Processing Facility radioactive operations -- Part 2, Glass making  

SciTech Connect

The Savannah River Site`s Defense Waste Processing Facility (DWPF) near Aiken, SC is the nation`s first and world`s largest vitrification facility. Following a ten year construction period and nearly 3 year non-radioactive test program, the DWPF began radioactive operations in March, 1996. The results of the first 8 months of radioactive operations are presented. Topics include facility production from waste preparation batching to canister filling.

Carter, J.T.; Rueter, K.J.; Ray, J.W.; Hodoh, O.

1996-12-31

377

"Radio-Active" Learning: Visual Representation of Radioactive Decay Using Dice  

ERIC Educational Resources Information Center

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…

Klein, Lynda; Kagan, David

2010-01-01

378

Radioactive Waste Control and Controversy: The History of Radioactive Waste Regulation in the UK  

Microsoft Academic Search

A hundred years on from the discovery of radioactivity, we have the first book describing the history of the regulation in the UK of the waste arising from its many uses. The first book? Believe it or not, yes. There have been others which provide commentaries on the development (or hapless evolution?) of policy per se and it would be

J H Jackson

1999-01-01

379

Development and application of a radioactivity characterization system for low-level radioactive waste  

NASA Astrophysics Data System (ADS)

Low-level technological radioactive wastes, in Spain, are commonly produced in research and medical centers. These wastes must be characterized before conditioning in order to determine their radioactive content for inventory purposes. A prototype has been designed for beta-gamma radiological characterization of standardized 25 l bags containing heterogeneous low-density technological radioactive wastes within the density range 0.05-0.6 g/cm 3. The system consists of an iron shielding box with three NaI(Tl) and a silicon implanted detectors for gamma and gross beta activity determinations, respectively. The study of the measurement method, carried out with rotating scanning, included the optimization of the detection solid angle to minimize the uncertainties and the influence of the relative position of the radioactive material. Several materials and densities, in the range aforementioned, were considered to obtain the experimental attenuation factors, used for fitting a correction algorithm in function of density and ?-emission energy. The sensitivity of this method, calculated for the most frequent average density of this kind of waste (0.1 g/cm 3), is lower than 50 Bq/kg for the main ?- ? emitters ( 137Cs and 60Co) and lower than 480 Bq/kg for gross beta activity.

Espartero, A. G.; Piña, G.; Suárez, J. A.

1999-02-01

380

Titanate-based adsorbents for radioactive ions entrapment from water  

NASA Astrophysics Data System (ADS)

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.

Yang, Dongjiang; Liu, Hongwei; Zheng, Zhanfeng; Sarina, Sarina; Zhu, Huaiyong

2013-02-01

381

49 CFR 172.403 - Class 7 (radioactive) material.  

Code of Federal Regulations, 2013 CFR

... false Class 7 (radioactive) material. 172.403 Section 172.403...Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS HAZARDOUS...

2013-10-01

382

49 CFR 177.842 - Class 7 (radioactive) material.  

Code of Federal Regulations, 2013 CFR

... false Class 7 (radioactive) material. 177.842 Section 177.842...Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS CARRIAGE BY PUBLIC...

2013-10-01

383

Th isotope and U-series studies of subduction-related volcanic rocks  

SciTech Connect

The activities of 6-7 radionuclides measured by alpha spectrometry are reported for 35 samples of recent volcanic rocks from 24 volcanoes in 9 arcs. These include continental margins (Cascades, Alaska, Costa Rica), island arcs (the Sunda, Banda, and Sangihe arcs of Indonesia, Marianas, Japan, Aleutians, Antilles, Tonga), and a backarc basin (Lau Basin). Enrichment of {sup 238}U over {sup 230}Th is more common and greater in these subduction-related volcanics than in those from other tectonic environments. {sup 230}Th/{sup 232}Th ratios also extend to higher values, both in absolute numbers and relative to other isotope ratios. Enrichment of {sup 210}Po and {sup 226}Ra over {sup 230}Th is widespread and is more common and greater in island arcs than continental margins. The level of Po or Ra enrichment is similar to that in ocean island and ridge basalts and deceases with differentiation. The differences in Th-U systematics between subduction-related and other volcanic rocks are attributed to variations in the process of melt extraction, changes in bulk partition coefficients within the mantle wedge, or preferential addition of U from subducted lithosphere. Ra enrichments are attributed to partial melting processes which are similar to those at ocean ridges. Smaller excesses at continental margins are attributed either to slower ascent or to differences in the process of melt formation beneath continents.

Gill, J.B.; Williams, R.W. (Univ. of California, Santa Cruz (USA))

1990-05-01

384

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

Microsoft Academic Search

Pleistocene raised marine deposits in southeastern Tunisia consist of a siliciclastic unit that culminates at +3m asl, overlain by a carbonate-rich unit with Strombus bubonius that culminates at +5m 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

Younes Jedoui; Jean-Louis Reyss; Nejib Kallel; Mabrouk Montacer; Eric Davaud

2003-01-01

385

25 Years of Radioactive Beams at TRIUMF  

NASA Astrophysics Data System (ADS)

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.

D'Auria, John M.

2012-10-01

386

DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS  

SciTech Connect

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.

NA

2004-11-22

387

Laser ion sources for radioactive beams (invited).  

PubMed

Resonant ionisation laser ion sources are nowadays extensively used, when available, at many leading on-line facilities. Moreover, new laser ion sources are now under development in most of the recent on-line facility projects under construction worldwide. This success is mainly due to the reliability, the ionization efficiency and the high purity that this type of source can achieve for the production of radioactive species and for a large range of chemical elements. Laser ion sources for radioactive beams gather many different systems such as dye laser or all-solid state titanium:sapphire laser systems, high or low repetition rates, hot cavities or gas cells, additional selectivity by using chemical techniques, or the LIST technique (laser ion source trap). In this paper, the physics of laser ion sources will be described with the current limitations and challenges for the future. An overview of the laser ion source facilities will be given, with an emphasis on the ongoing developments and perspectives on LIS. PMID:22380257

Lecesne, N

2012-02-01

388

Laser ion sources for radioactive beams (invited)  

NASA Astrophysics Data System (ADS)

Resonant ionisation laser ion sources are nowadays extensively used, when available, at many leading on-line facilities. Moreover, new laser ion sources are now under development in most of the recent on-line facility projects under construction worldwide. This success is mainly due to the reliability, the ionization efficiency and the high purity that this type of source can achieve for the production of radioactive species and for a large range of chemical elements. Laser ion sources for radioactive beams gather many different systems such as dye laser or all-solid state titanium:sapphire laser systems, high or low repetition rates, hot cavities or gas cells, additional selectivity by using chemical techniques, or the LIST technique (laser ion source trap). In this paper, the physics of laser ion sources will be described with the current limitations and challenges for the future. An overview of the laser ion source facilities will be given, with an emphasis on the ongoing developments and perspectives on LIS.

Lecesne, N.

2012-02-01

389

Field tests using radioactive matter 2.  

PubMed

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

Rulik, P; Prouza, Z; Hovorka, J; Beckova, V; Cespirova, I; Fronka, A; Helebrant, J; Hulka, J; Kuca, P; Skrkal, J

2013-04-01

390

Radioactive materials in biosolids : dose modeling.  

SciTech Connect

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.

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

391

2p radioactivity studied by tracking technique  

SciTech Connect

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.

Mukha, Ivan [CSIC-IFIC Universidad de Valencia, E-46071 Valencia (Spain)

2010-06-01

392

Radioactivity in trinitite six decades later.  

PubMed

The first nuclear explosion test, named the Trinity test, was conducted on July 16, 1945 near Alamogordo, New Mexico. In the tremendous heat of the explosion, the radioactive debris fused with the local soil into a glassy material named Trinitite. Selected Trinitite samples from ground zero (GZ) of the test site were investigated in detail for radioactivity. The techniques used included alpha spectrometry, high-efficiency gamma-ray spectrometry, and low-background beta counting, following the radiochemistry for selected radionuclides. Specific activities were determined for fission products (90Sr, 137Cs), activation products (60Co, 133Ba, 152Eu, 154Eu, 238Pu, 241Pu), and the remnants of the nuclear fuel (239Pu, 240Pu). Additionally, specific activities of three natural radionuclides (40K, 232Th, 238U) and their progeny were measured. The determined specific activities of radionuclides and their relationships are interpreted in the context of the fission process, chemical behavior of the elements, as well as the nuclear explosion phenomenology. PMID:16102878

Parekh, Pravin P; Semkow, Thomas M; Torres, Miguel A; Haines, Douglas K; Cooper, Joseph M; Rosenberg, Peter M; Kitto, Michael E

2006-01-01

393

Resonant laser ionization of radioactive atoms*1  

NASA Astrophysics Data System (ADS)

Intense radioactive ion beams are produced by the isotope separation on-line method. The resonance ionization laser ion source (RILIS) can provide the chemical selectivity to separate beams with reduced isobaric contamination. The hot cavity RILIS at ISOLDE (CERN) uses copper vapor laser pumped dye lasers for the resonant transitions. Up to now 22 elements have been ionized with efficiencies of the order of 10%. Additional elements have been ionized with similar RILIS set-ups at the Institute of Spectroscopy (Troitsk), IRIS (Gatchina), Mainz University and TIARA (Takasaki). Ideas are discussed for future developments of this type of RILIS, which could further improve the efficiency, selectivity, rapidity of release and stability of the operation. The RILIS can also be applied for atomic spectroscopy studies of exotic radioactive isotopes, which are produced at rates of few atoms per second only. An interesting parallel is shown to the atomic vapor laser isotope separation (AVLIS), a large-scale application of resonance ionization, which could be used for the isotope enrichment of macroscopic amounts: tens of kg per h.

Köster, U.; Fedoseyev, V. N.; Mishin, V. I.

2003-06-01

394

The political science of radioactive waste disposal  

SciTech Connect

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}

Jacobi, L.R. Jr. [Texas Los Level Radioactive Waste Disposal Authority, Austin, TX (United States)

1996-06-01

395

Cross section measurements on radioactive samples  

SciTech Connect

We have developed a system over the past few years at the Manuel Lujan, Jr. Neutron Scattering Center (LANSCE) for making (n,p) and (n,{alpha}) measurements on (mainly) radioactive nuclei. Measurements have included {sup 7}Be(n,p){sup 7}Li, {sup 14}N(n,p){sup 14}C, {sup 17}O(n,{alpha}){sup 14}C, {sup 22}Na(n,p){sup 22}Ne, {sup 22}Na(n,{alpha}){sup 19}F, {sup 35}Cl(n,p){sup 35}S and {sup 36}Cl(n,p){sup 36}S. The major basic physics motivation for these measurements has been the nuclear astrophysics to be learned. Currently, we are assembling a 4{pi} detector of barium fluoride (BaF{sub 2}) for making (n,{gamma}) measurements on radioactive nuclei with relatively short half lives. Once operational, this new detector should allow us to expand our measurements to many more nuclei, and to a broader range of nuclear physics and nuclear astrophysics issues addressed. Results of recent measurements are given and future plans are discussed. 38 refs., 2 figs.

Koehler, P.E.; O'Brien, H.A.

1990-01-01

396

Radioactive-waste incineration at Purdue University  

SciTech Connect

A study conducted at Purdue University to evaluate the feasibility of using a small (45 kg/h), inexpensive (less than $10K) incinerator for incinerating low-level radioactive waste is described. An oil-fired, dual-chamber pathological waste incinerator was installed on a 12.7-cm-thick concrete floor in a metal quonset building. A standard EPA Method 5 sampling train was used to obtain stack samples. Also, stack gas velocity was measured with a type 5 pitot tube; stack temperature was measured with a thermocouple and pyrometer. The incinerator was tested for emissions from incineration of laboratory animal carcasses, liquid scintillation fluid, and trash. Emissions measured were particulates, SO/sub x/, NO/sub x/, Cl, CO, CO/sub 2/, H/sub 2/O, and unburned hydrocarbons in the particulate fraction. Three analyses were then averaged to arrive at the final determinations. Results of the study demonstrated the feasibility and cost-effectiveness of incinerating radioactive animal carcasses and liquid scintillation fluids, since emissions from those waste types were within EPA and State of Indiana limits. However, emissions from burning of trash exceeded State of Indiana limits. Therefore, incineration of trash alone, particularly if it contains glass or significant amounts of plastic, is not a recommended use of the tested equipment.

Not Available

1982-11-01

397

Radioactivity in municipal sewage and sludge.  

PubMed Central

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.

Martin, J E; Fenner, F D

1997-01-01

398

Directions in low-level radioactive waste management: A brief history of commercial low-level radioactive waste disposal  

SciTech Connect

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.

Not Available

1994-08-01

399

INEEL Radioactive Liquid Waste Reduction Program  

SciTech Connect

Reduction of radioactive liquid waste, much of which is Resource Conservation and Recovery Act (RCRA) listed, is a high priority at the Idaho National Technology and Engineering Center (INTEC). Major strides in the past five years have lead to significant decreases in generation and subsequent reduction in the overall cost of treatment of these wastes. In 1992, the INTEC, which is part of the Idaho National Environmental and Engineering Laboratory (INEEL), began a program to reduce the generation of radioactive liquid waste (both hazardous and non-hazardous). As part of this program, a Waste Minimization Plan was developed that detailed the various contributing waste streams, and identified methods to eliminate or reduce these waste streams. Reduction goals, which will reduce expected waste generation by 43%, were set for five years as part of this plan. The approval of the plan led to a Waste Minimization Incentive being put in place between the Department of Energy ? Idaho Office (DOE-ID) and the INEEL operating contractor, Lockheed Martin Idaho Technologies Company (LMITCO). This incentive is worth $5 million dollars from FY-98 through FY-02 if the waste reduction goals are met. In addition, a second plan was prepared to show a path forward to either totally eliminate all radioactive liquid waste generation at INTEC by 2005 or find alternative waste treatment paths. Historically, this waste has been sent to an evaporator system with the bottoms sent to the INTEC Tank Farm. However, this Tank Farm is not RCRA permitted for mixed wastes and a Notice of Non-compliance Consent Order gives dates of 2003 and 2012 for removal of this waste from these tanks. Therefore, alternative treatments are needed for the waste streams. This plan investigated waste elimination opportunities as well as treatment alternatives. The alternatives, and the criteria for ranking these alternatives, were identified through Value Engineering meetings with all of the waste generators. The most promising alternatives were compared by applying weighting factors to each based on how well the alternative met the established criteria. From this information, an overall ranking of the various alternatives was obtained and a path forward recommended.

C. B. Millet; J. L. Tripp; K. E. Archibald; L. Lauerhauss; M. D. Argyle; R. L. Demmer

1999-02-01

400

INEEL Radioactive Liquid Waste Reduction Program  

SciTech Connect

Reduction of radioactive liquid waste, much of which is Resource Conservation and Recovery Act (RCRA) listed, is a high priority at the Idaho National Technology and Engineering Center (INTEC). Major strides in the past five years have lead to significant decreases in generation and subsequent reduction in the overall cost of treatment of these wastes. In 1992, the INTEC, which is part of the Idaho National Environmental and Engineering Laboratory (INEEL), began a program to reduce the generation of radioactive liquid waste (both hazardous and non-hazardous). As part of this program, a Waste Minimization Plan was developed that detailed the various contributing waste streams, and identified methods to eliminate or reduce these waste streams. Reduction goals, which will reduce expected waste generation by 43%, were set for five years as part of this plan. The approval of the plan led to a Waste Minimization Incentive being put in place between the Department of Energy–Idaho Office (DOE-ID) and the INEEL operating contractor, Lockheed Martin Idaho Technologies Company (LMITCO). This incentive is worth $5 million dollars from FY-98 through FY-02 if the waste reduction goals are met. In addition, a second plan was prepared to show a path forward to either totally eliminate all radioactive liquid waste generation at INTEC by 2005 or find alternative waste treatment paths. Historically, this waste has been sent to an evaporator system with the bottoms sent to the INTEC Tank Farm. However, this Tank Farm is not RCRA permitted for mixed wastes and a Notice of Non-compliance Consent Order gives dates of 2003 and 2012 for removal of this waste from these tanks. Therefore, alternative treatments are needed for the waste streams. This plan investigated waste elimination opportunities as well as treatment alternatives. The alternatives, and the criteria for ranking these alternatives, were identified through Value Engineering meetings with all of the waste generators. The most promising alternatives were compared by applying weighting factors to each based on how well the alternative met the established criteria. From this information, an overall ranking of the various alternatives was obtained and a path forward recommended.

Tripp, Julia Lynn; Archibald, Kip Ernest; Argyle, Mark Don; Demmer, Ricky Lynn; Miller, Rose Anna; Lauerhass, Lance

1999-03-01

401

Characterization of plutonium in Maxey Flats radioactive trench leachates  

Microsoft Academic Search

Plutonium in trench leachates at the Maxey Flats radioactive waste disposal site exists as dissolved species, primarily complexes of the tetravalent ion with strong organic ligands such as ethylenediaminetetraacetic acid. The complexes are not sorbed well by sediment and are only partly precipitated by ferric hydroxide. These results indicate the importance of isolating radioactive waste from organic matter. 3 tables.

J. M. Cleveland; T. F. Rees

1981-01-01

402

Radioactive effluents, Portsmouth Gaseous Diffusion Plant, calendar year 1982  

Microsoft Academic Search

Radioactive discharges from the Portsmouth Gaseous Diffusion Plant are discussed and tabulated. Tables indicate both the location of the discharge and the nuclides discharged. All discharges for 1982 are well below the Radioactive Concentration Guide limits specified in DOE Order 5480.1, Chapter XI. 1 figure.

T. A. Acox; L. F. Hary; L. S. Klein

1983-01-01

403

Radioactive Waste Information for 1998 and Record-To-Date  

SciTech Connect

This document presents detailed data, bar graphs, and pie charts on volume, radioactivity; isotopic identity, origin, and status of radioactive waste for calendar year 1998 at the Idaho National Engineering and Environmental Laboratory (INEEL). The data presented are from the INEEL Integrated Waste Information System.

D. L. French; R. E. Tallman; K. A. Taylor

1999-07-01

404

The production and generation of radioactive ion beams (RIBs)  

SciTech Connect

There is a strong interest in physics with radioactive ion beams, which has triggered a number of projects where nuclear physics installations are upgraded with accelerators for low charge state radioactive beams. A survey of the status of these projects is given with emphasis on the low energy linacs, which are limiting the acceptance and transmission of these low current ion beams.

Schempp, A. [Institut fuer Angewandte Physik, J. W. Goethe-Universitaet, D-60054 Frankfurt (Germany)

1999-06-10

405

R&D on the Geant4 Radioactive Decay Physics  

NASA Astrophysics Data System (ADS)

We present validation measurements for the Geant4 radioactive decay simulation following a self-consistent approach. The validation is based on gamma spectroscopy measurements with HPGe and Nal detectors. In addition we present a re-designed radioactive decay simulation for Geant4, with extended functionality, such as support for long term activation, and programmed to modern coding standards.

Hauf, S.; Hoffmann, D. H. H.; Lang, P.; Neff, S.; Kuster, M.; Bati?, M.; Pia, M. G.; Bell, Z. W.; Weidenspointner, G.; Zoglauer, A.

2012-08-01

406

Radioactive Effluents from Nuclear Power Plants Annual Report 2007  

SciTech Connect

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.

U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation

2010-12-10

407

Radioactive Effluents from Nuclear Power Plants Annual Report 2008  

SciTech Connect

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.

U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation

2010-12-10

408

Manual overlay dose assessment technique for elevated radioactive releases  

Microsoft Academic Search

The US Nuclear Regulatory Commission (NRC) requires nuclear power plants to have an emergency plan that incorporates a systems for making real-time site-specific predictions of atmosphere transport and diffusion following an accidental radioactive release. This information provides valuable input in assessing the consequences of airborne radioactive releases, making protective action decisions, and directing the movement of field monitoring teams. Computerized

S. A. Vigeant; C. A. Mazzola

1985-01-01

409

Transporting radioactive materials: Q & A to your questions  

SciTech Connect

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.

Not Available

1993-04-01

410

Development of radioactive stent using HANARO research reactor.  

National Technical Information Service (NTIS)

Radioactive cylindrical was prepared by neutron irradiation of pre-made non- radioactive '1'6'5 Ho-sleeve, which was made by casting polyurethane solution containing '1'6'5'Ho(NO(sub 3))(sub 3) in THF+DMF (10:1) solvent in cylindrical glass tube. Its leng...

K. B. Park J. Kim H. Han B. Shin Y. Kim

1997-01-01

411

Control of radioactive material transport in sodium-cooled reactors  

Microsoft Academic Search

The Radioactivity Control Technology (RCT) program was established by the Department of Energy to develop and demonstrate methods to control radionuclide transport to ex-core regions of sodium-cooled reactors. This radioactive material is contained within the reactor heat transport system with any release to the environment well below limits established by regulations. However, maintenance, repair, decontamination, and disposal operations potentially expose

Brehm

2008-01-01

412

Behavior of Highly Radioactive Iodine on Charcoal in Moist Air.  

National Technical Information Service (NTIS)

The behavior of highly radioactive iodine adsorbed on charcoal exposed to moist air (110 torr water vapor partial pressure) was investigated in a series of six experiments. The amount of radioactive exp 130 I on the well-insulated 28-cm exp 3 bed ranged f...

R. A. Lorenz S. R. Manning W. J. Martin

1976-01-01

413

Protocols for implementing DOE authorized release of radioactive scrap metals  

Microsoft Academic Search

A process to implement the US Department of Energy`s (DOE) policy for authorized release of radioactive materials from DOE facilities is provided in the Draft Handbook for Controlling Release for Reuse or Recycle of Property Containing Residual Radioactive Material, published by DOE in 1997 and distributed to DOE field offices for interim use and implementation. The authorized release of such

S. Y. Chen; J. Arnish; S. Kamboj; L. A. Nieves

1999-01-01

414

Assessment of recycling or disposal alternatives for radioactive scrap metal  

Microsoft Academic Search

The US Department of Energy, Office of Environmental Restoration and Waste Management, is participating with the Organization for Economic Cooperation and Development (OECD) is an evaluation of management alternatives for radioactive scarp metals. For this purpose, Argonne National Laboratory is assessing alternatives for radioactive scrap metals. For this purpose, Argonne National Laboratory is assessing environmental and societal implications of recycling

W. E. Murphie; M. J. Lilly; L. A. Nieves; S. Y. Chen

1993-01-01

415

Dismantlement and radioactive waste management of North Korean nuclear facilities  

Microsoft Academic Search

One critical aspect of any denuclearization of the Democratic People's Republic of Korea (DPRK) involves dismantlement of its nuclear facilities and management of their associated radioactive wastes. The decommissioning problem for its two principal operational plutonium facilities at Yongbyun, the 5MWe nuclear reactor and the Radiochemical Laboratory reprocessing facility, alone present a formidable challenge. Dismantling those facilities will create radioactive

Jooho Whang; George Thomas Baldwin

2004-01-01

416

Dismantlement and Radioactive Waste Management of DPRK Nuclear Facilities  

Microsoft Academic Search

One critical aspect of any denuclearization of the Democratic Peoples Republic of Korea (DPRK) involves dismantlement of its nuclear facilities and management of their associated radioactive wastes. The decommissioning problem for its two principal operational plutonium facilities at Yongbyun, the 5MWe nuclear reactor and the Radiochemical Laboratory reprocessing facility, alone present a formidable challenge. Dismantling those facilities will create radioactive

W. Jooho; G. T. Baldwin

2005-01-01

417

Construction module protecting against emissions from radioactive material and method  

Microsoft Academic Search

A construction module is described for use in protecting personnel against emissions from radioactive material comprising: a shaped member suitable for assembly with other shaped members to form a structure for shielding personnel; said shaped members being formed from suitable shielding material capable of excluding passage of emissions from radioactive material and having adjoining surfaces for reception closely adjacent complementary

1993-01-01

418

MONITORING FOR AIRBORNE RADIOACTIVE MATERIALS AT HANFORD ATOMIC PRODUCTS OPERATION  

Microsoft Academic Search

Methods employed at Hanford Atomic Products Operation to monitor for air-; botne radioactive materials are described. Criteria used to establish the ; atmospheric monitoring program include recommendations of the National Committee ; on Radioactive Protection, H.A.P.O. Radiation Protection Standards, amounts and ; types of radioisotopes discharged to the atmosphere, and the meteorology and ; population density of the plant envirous.

Soldat

1959-01-01

419

Quality assurance for packaging of radioactive and hazardous materials  

Microsoft Academic Search

The Department of Energy (DOE) has required for many years that quality assurance programs be established and implemented for the packaging of radioactive and hazardous materials. This paper identifies various requirement principles and related actions involved in establishing effective quality assurance for packaging of radioactive and hazardous materials. A primary purpose of these quality assurance program activities is to provide

Gustafson

1986-01-01

420

Security in the Transport of Radioactive Material: Implementing Guide  

Microsoft Academic Search

This publication addresses the vulnerability of radioactive material during transport. Given the international concern over acts of nuclear terrorism, it is imperative to have a well defined plan for the security of sensitive materials during their transport. The present publication provides guidance on implementing, maintaining or enhancing a State’s nuclear security regime to protect radioactive material in transport against theft,

2010-01-01

421

Radioactive effluents, Portsmouth Gaseous Diffusion Plant, calendar year 1982  

SciTech Connect

Radioactive discharges from the Portsmouth Gaseous Diffusion Plant are discussed and tabulated. Tables indicate both the location of the discharge and the nuclides discharged. All discharges for 1982 are well below the Radioactive Concentration Guide limits specified in DOE Order 5480.1, Chapter XI. 1 figure.

Acox, T.A.; Hary, L.F.; Klein, L.S.

1983-03-01

422

Characterization of a ceramic waste form encapsulating radioactive electrorefiner salt  

Microsoft Academic Search

Argonne National Laboratory has developed a ceramic waste form to immobilize radioactive waste salt produced during the electrometallurgical treatment of spent fuel. This study presents the first results from electron microscopy and durability testing of a ceramic waste form produced from that radioactive electrorefiner salt. The waste form consists of two primary phases: sodalite and glass. The sodalite phase appears

T. L. Moschetti; W. Sinkler; T. DiSanto; M. Noy; A. R. Warren; D. G. Cummings; S. G. Johnson; K. M. Goff; K. J. Bateman; S. M. Frank

1999-01-01

423

Regulatory Approaches for Solid Radioactive Waste Storage in Russia  

Microsoft Academic Search

The Russian Navy under the Arctic Military Environmental Cooperation (AMEC) Program has designated the Polyarninsky Shipyard as the regional recipient for solid radioactive waste (SRW) pretreatment and storage facilities. Waste storage technologies include containers and lightweight modular storage buildings. The prime focus of this paper is solid radioactive waste storage options based on the AMEC mission and Russian regulatory standards.

A. Griffith; S. Testov; A. Diaschev; A. Nazarian; A. Ustyuzhanin

2003-01-01

424

Application of microwave solidification technology to radioactive waste  

Microsoft Academic Search

The EPA has declared vitrification to be the Best Available Demonstrated Technology (BDAT) for High Level Radioactive Waste (40 CFR 268.42). Vitrification has been chosen as the method of choice for treating a number of radioactive residues and wastes in the DOE complex. Vitrification offers advantages of waste volume reduction, the ability to handle changing waste forms, and a stable,

M. Harris; G. Sprenger; B. Roushey; G. Fenner; R. Nieweg

1995-01-01

425

An Excel[TM] Model of a Radioactive Series  

ERIC Educational Resources Information Center

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.)

Andrews, D. G. H.

2009-01-01

426

Membrane Treatment of Liquid Salt Bearing Radioactive Wastes  

Microsoft Academic Search

The main fields of introduction and application of membrane methods for preliminary treatment and processing salt liquid radioactive waste (SLRW) can be nuclear power stations (NPP) and enterprises on atomic submarines (AS) utilization. Unlike the earlier developed technology for the liquid salt bearing radioactive waste decontamination and concentrating this report presents the new enhanced membrane technology for the liquid salt

S. A. Dmitriev; D. V. Adamovich; V. I. Demkin; E. M. Timofeev

2003-01-01

427

10 CFR 20.1005 - Units of radioactivity.  

Code of Federal Regulations, 2010 CFR

... 1 2009-01-01 2009-01-01 false Units of radioactivity. 20.1005 Section 20.1005 Energy NUCLEAR REGULATORY...RADIATION General Provisions § 20.1005 Units of radioactivity. For the purposes of this part, activity is...

2009-01-01

428

The Identification of Factors Influencing College Students' Attitudes toward Radioactivity.  

ERIC Educational Resources Information Center

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…

Crater, Harold L., Jr.

429

10 CFR 20.1005 - Units of radioactivity.  

Code of Federal Regulations, 2010 CFR

... 1 2010-01-01 2010-01-01 false Units of radioactivity. 20.1005 Section 20.1005 Energy NUCLEAR REGULATORY...RADIATION General Provisions § 20.1005 Units of radioactivity. For the purposes of this part, activity is...

2010-01-01

430

LIQUID RADIOACTIVE WASTE DISPOSAL FACILITY. Final Engineering Report  

Microsoft Academic Search

A liquld radioactive waste disposal facility was designed, developed, ; and installed at Nuclear Defense Laboratory for extensive tests and evaluation. ; The facility is being used for concentration of radioactive wastes from the Army ; nuclear power program and biological and medical research. It employs a Pfaulder ; Wiped Film Evaporator to effect gross decontamination of the waste and

W. F. Swanton; M. L. Hyman

1962-01-01

431

Radioactive waste storage and disposal in the UK  

Microsoft Academic Search

Even though mankind has evolved in a naturally radioactive environment, the existence of radiation was only discovered about a century or so ago. Since then the use of radioactive materials has grown rapidly and they are now used extensively in hospitals for medical diagnosis and treatment, and in general industry where they are used for measurement and inspection, as well

A. D. Johnson; P. R. Maul; F. H. Passant

1990-01-01

432

SAFETY INDICATORS IN BOREHOLE DISPOSAL OF SEALED RADIOACTIVE SOURCES  

Microsoft Academic Search

The Radioactive Waste Management Laboratory (RWML) at the Energy and Nuclear Research Institute of São Paulo, Brazil, is developing the concept of a geological repository adequate for the Brazilian inventory of disused sealed radioactive sources. Sealed sources are numbered to hundreds of thousands, have increasingly been used in industry as well as in medical applications in the last decades, and

Eliana Rodrigues Leite; Rosana Lágua de Oliveira; Roberto Vicente

433

Radioactive ion beam facilities in Europe  

NASA Astrophysics Data System (ADS)

The past two decades have seen extraordinarily rapid development of radioactive beam physics throughout the world and in particular in Europe. The important scientific advances have stemmed from a large number of facilities. Previously existing stable beam machines have been adapted to produce rare isotope beams and dedicated facilities have come on-line. This talk gives an overview of the present European installations highlighting their complementary nature. The European roadmap calls for the construction of two next generation facilities: FAIR making use of projectile fragmentation and EURISOL based on the ISOL technique. The future FAIR facility will be described and the path towards EURISOL presented in the light of the construction of "intermediate" generation facilities SPIRAL2, HIE ISOLDE and SPES and results from the ongoing EURISOL Design Study.

Blumenfeld, Y.

2008-10-01

434

Evaluation of radioactive scrap metal recycling  

SciTech Connect

This report evaluates the human health risks and environmental and socio-political impacts of options for recycling radioactive scrap metal (RSM) or disposing of and replacing it. Argonne National Laboratory (ANL) is assisting the US Department of Energy (DOE), Office of Environmental Restoration and Waste Management, Oak Ridge Programs Division, in assessing the implications of RSM management alternatives. This study is intended to support the DOE contribution to a study of metal recycling being conducted by the Task Group on Recycling and Reuse of the Organization for Economic Cooperation and Development. The focus is on evaluating the justification for the practice of recycling RSM, and the case of iron and steel scrap is used as an example in assessing the impacts. To conduct the evaluation, a considerable set of data was compiled and developed. Much of this information is included in this document to provide a source book of information.

Nieves, L.A.; Chen, S.Y.; Kohout, E.J.; Nabelssi, B.; Tilbrook, R.W.; Wilson, S.E.

1995-12-01

435

Reconnaissance for radioactive deposits in Alaska, 1953  

USGS Publications Warehouse

During the summer of 1953 the areas investigated for radioactive deposits in Alaska were on Nikolai Creek near Tyonek and on Likes Creek near Seward in south-central Alaska where carnotite-type minerals had been reported; in the headwaters of the Peace River in the eastern part of the Seward Peninsula and at Gold Bench on the South Fork of the Koyukuk River in east-central Alaska, where uranothorianite occurs in places associated with base metal sulfides and hematite; in the vicinity of Port Malmesbury in southeastern Alaska to check a reported occurrence of pitchblende; and, in the Miller House-Circle Hot Springs area of east-central Alaska where geochemical studies were made.

Matzko, John J.; Bates, Robert G.

1955-01-01

436

Radioactive krypton background evaluation using atom counting  

NASA Astrophysics Data System (ADS)

The beta-decay of 85Kr is a significant radioactive background for experiments that use liquified noble gases to search for dark matter and measure the low-energy solar neutrino flux. While there are several proposed methods for reducing Kr levels in these experiments, an independent technique is needed for measuring very low Kr levels. By selectively exciting Kr atoms to a metastable state, capturing them in a magneto-optical trap (MOT), and detecting fluorescence from the trapped atoms, individual Kr atoms can be counted with a high signal-to-noise ratio. This approach could be used to ascertain Kr impurity levels in other noble gases, with an estimated sensitivity of 3×10.

McKinsey, D. N.; Orzel, C.

2005-06-01

437

Greater confinement disposal of radioactive wastes  

SciTech Connect

Low-level radioactive waste (LLW) includes a broad spectrum of different radionuclide concentrations, half-lives, and hazards. Standard shallow-land burial practice can provide adequate protection of public health and safety for most LLW. A small volume fraction (approx. 1%) containing most of the activity inventory (approx. 90%) requires specific measures known as greater-confinement disposal (GCD). Different site characteristics and different waste characteristics - such as high radionuclide concentrations, long radionuclide half-lives, high radionuclide mobility, and physical or chemical characteristics that present exceptional hazards - lead to different GCD facility design requirements. Facility design alternatives considered for GCD include the augered shaft, deep trench, engineered structure, hydrofracture, improved waste form, and high-integrity container. Selection of an appropriate design must also consider the interplay between basic risk limits for protection of public health and safety, performance characteristics and objectives, costs, waste-acceptance criteria, waste characteristics, and site characteristics.

Trevorrow, L.E.; Gilbert, T.L.; Luner, C.; Merry-Libby, P.A.; Meshkov, N.K.; Yu, C.

1985-01-01

438

Hydrothermal processing of radioactive combustible waste  

SciTech Connect

Hydrothermal processing has been demonstrated for the treatment of radioactive combustible materials for the US Department of Energy. A hydrothermal processing system was designed, built and tested for operation in a plutonium glovebox. Presented here are results from the study of the hydrothermal oxidation of plutonium and americium contaminated organic wastes. Experiments show the destruction of the organic component to CO{sub 2} and H{sub 2}O, with 30 wt.% H{sub 2}O{sub 2} as an oxidant, at 540 C and 46.2 MPa. The majority of the actinide component forms insoluble products that are easily separated by filtration. A titanium liner in the reactor and heat exchanger provide corrosion resistance for the oxidation of chlorinated organics. The treatment of solid material is accomplished by particle size reduction and the addition of a viscosity enhancing agent to generate a homogeneous pumpable mixture.

Worl, L.A.; Buelow, S.J.; Harradine, D.; Le, L.; Padilla, D.D.; Roberts, J.H.

1998-09-01

439

Reduction of INTEC Analytical Radioactive Liquid Waste  

SciTech Connect

This report details the evaluation of the reduction in radioactive liquid waste from the analytical laboratories sent to the Process Effluent Waste system (deep tanks). The contributors are the Analytical Laboratories Department (ALD), the Waste Operations Department, the laboratories at CPP-637, and natural run off. Other labs were contacted to learn of methods used and if any new technologies had emerged. A waste generation database was made from the current methods in use in the ALD. From this database, methods were targeted to reduce waste. Individuals were contacted on ways to reduce waste. The results are: a new method generating much less waste, several methods being handled differently, some cleaning processes being changed to reduce waste, and changes to reduce chemicals to waste.

Johnson, Virgil James; Hu, Jian Sheng; Chambers, Andrea

1999-06-01

440

Reduction of INTEC Analytical Radioactive Liquid Wastes  

SciTech Connect

This report details the evaluation of the reduction in radioactive liquid waste from the analytical laboratories sent to the Process Effluent Waste system (deep tanks). The contributors are the Analytical Laboratories Department (ALD), the Waste Operations Department, the laboratories at CPP-637, and natural run off. Other labs were contacted to learn the methods used and if any new technologies had emerged. A waste generation database was made from the current methods in used in the ALD. From this database, methods were targeted to reduce waste. Individuals were contacted on ways to reduce waste. The results are: a new method generating much less waste, several methods being handled differently, some cleaning processes being changed to reduce waste, and changes to reduce chemicals to waste.

V. J. Johnson; J. S. Hu; A. G. Chambers

1999-06-01

441

Dutch geologic radioactive waste disposal project  

NASA Astrophysics Data System (ADS)

Geologic disposal of radioactive waste is reviewed. The radionuclide release consequences of an accidental flooding of the underground excavations was studied. The results of the quantitative examples made for different effective cross sections of the permeable layer connecting the mine excavations with the boundary of the salt dome are that under all circumstances the concentration of the waste nuclides in drinking water will remain well within the ICRP maximum permissible concentrations. Further analysis work was done on what minima can be achieved for both the maximum local rock salt temperatures at the disposal borehole walls and the maximum global rock salt temperatures halfway between a square of disposal boreholes. Different multilayer disposal configurations were analyzed and compared.

Hamstra, J.; Verkerk, B.

442

Room air monitor for radioactive aerosols  

DOEpatents

A housing assembly for use with a room air monitor for simultaneous collection and counting of suspended particles includes a casing containing a combination detector-preamplifier system at one end, a filter system at the other end, and an air flow system consisting of an air inlet formed in the casing between the detector-preamplifier system and the filter system and an air passageway extending from the air inlet through the casing and out the end opposite the detector-preamplifier combination. The filter system collects suspended particles transported directly through the housing by means of the air flow system, and these particles are detected and examined for radioactivity by the detector-preamplifier combination. 2 figs.

Balmer, D.K.; Tyree, W.H.

1987-03-23

443

Feasibility analysis of recycling radioactive scrap steel  

SciTech Connect

The purpose of this study is to: (1) establish a conceptual design that integrates commercial steel mill technology with radioactive scrap metal (RSM) processing to produce carbon and stainless steel sheet and plate at a grade suitable for fabricating into radioactive waste containers; (2) determine the economic feasibility of building a micro-mill in the Western US to process 30,000 tons of RSM per year from both DOE and the nuclear utilities; and (3) provide recommendations for implementation. For purposes of defining the project, it is divided into phases: economic feasibility and conceptual design; preliminary design; detail design; construction; and operation. This study comprises the bulk of Phase 1. It is divided into four sections. Section 1 provides the reader with a complete overview extracting pertinent data, recommendations and conclusions from the remainder of the report. Section 2 defines the variables that impact the design requirements. These data form the baseline to create a preliminary conceptual design that is technically sound, economically viable, and capitalizes on economies of scale. Priorities governing the design activities are: (1) minimizing worker exposure to radionuclide hazards, (2) maximizing worker safety, (3) minimizing environmental contamination, (4) minimizing secondary wastes, and (5) establishing engineering controls to insure that the plant will be granted a license in the state selected for operation. Section 3 provides details of the preliminary conceptual design that was selected. The cost of project construction is estimated and the personnel needed to support the steel-making operation and radiological and environmental control are identified. Section 4 identifies the operational costs and supports the economic feasibility analysis. A detailed discussion of the resulting conclusions and recommendations is included in this section.

Nichols, F. [Manufacturing Sciences Corp., Woodland, WA (United States); Balhiser, B. [MSE, Inc., Butte, MT (United States); Cignetti, N. [Cignetti Associates, North Canton, OH (United States)] [and others

1995-09-01

444

Control of radioactive waste-glass melters  

SciTech Connect

Slurries of simulated high level radioactive waste and glass formers have been isothermally reacted and analyzed to identify the sequence of the major chemical reactions in waste vitrification, their effect on glass production rate, and the development of leach resistance. Melting rates of waste batches have been increased by the addition of reducing agents (formic acid, sucrose) and nitrates. The rate increases are attributable in part to exothermic reactions which occur at critical stages in the vitrification process. Nitrates must be balanced by adequate reducing agents to avoid the formation of persistent foam, which would destabilize the melting process. The effect of foaming on waste glass production rates is analyzed, and melt rate limitations defined for waste-glass melters, based upon measurable thermophysical properties. Minimum melter residence times required to homogenize glass and assure glass quality are much smaller than those used in current practice. Thus, melter size can be reduced without adversely affecting glass quality. Physical chemistry and localized heat transfer of the waste-glass melting process are examined, to refine the available models for predicting and assuring glass production rate. It is concluded that the size of replacement melters and future waste processing facilities can be significantly decreased if minimum heat transfer requirements for effective melting are met by mechanical agitation. A new class of waste glass melters has been designed, and proof of concept tests completed on simulated High Level Radioactive Waste slurry. Melt rates have exceeded 155 kg m{sup {minus}2} h{sup {minus}1} with slurry feeds (32 lb ft{sup {minus}2} h{sup {minus}1}), and 229 kg kg m{sup {minus}2} h{sup {minus}1} with dry feed (47 lb ft{sup {minus}2} h{sup {minus}1}). This is about 8 times the melt rate possible in conventional waste- glass melters of the same size. 39 refs., 5 figs., 9 tabs.

Bickford, D.F. (Westinghouse Savannah River Co., Aiken, SC (USA)); Hrma, P. (Case Western Reserve Univ., Cleveland, OH (USA)); Bowan, B.W. II (West Valley Nuclear Services Co., Inc., West Valley, NY (USA))

1990-01-01

445

Defense Waste Processing Facility Radioactive Operations - Year Two  

SciTech Connect

The Savannah River Site`s Defense Waste Processing Facility (DWPF) near Aiken, SC is the nation`s first high-level radioactive waste vitrification facility. This waste (130 million liters) which has been stored in carbon steel underground tanks and is now being pretreated, melted into a highly durable borosilicate glass and poured into stainless steel canisters for eventual disposal in a geologic repository. Following a ten-year construction period and nearly three-year nonradioactive test program, the DWPF began radioactive operations in March 1996. The first nine months of radioactive operations have been reported previously. As with any complex technical facility, difficulties were encountered during the transition to radioactive operations. Results of the second year of radioactive operations are presented in this paper. The discussion includes: feed preparation and glass melting, resolution of the melter pouring issues, improvements in processing attainment and throughput, and planned improvements in laboratory attainment and throughput.

Occhipinti, J.E.; Carter, J.T.; Edwards, R.E.; Beck, R.S.; Iverson, D.C.

1998-03-01

446

Leachate tests with sewage sludge contaminated by radioactive cesium.  

PubMed

The sewer systems of eastern Japan have transported radioactive fallout from the Fukushima Dai-ichi nuclear power plant accident to wastewater treatment plants, where the radioisotopes have accumulated. To better understand the potential problems associated with the disposal of contaminated sewage sludge in landfills, leachate tests were conducted with radioactive incinerator ash, cement solidification incinerator ash, and dewatered sludge cake. Radioactivity was undetectable in the eluate from incinerator ash and dewatered sludge cake, but about 30% of the radioactivity initially in cement solidification incinerator ash appeared in the eluate during the leaching experiments. Moreover, modification of test conditions revealed that the presence of Ca(2+) ions and strong alkali in the water that contacted the incinerator ash enhanced leaching of cesium. Lastly, the capacity of pit soil to absorb radioactive cesium was estimated to be at least 3.0 Bq/g (dry). PMID:23947711

Tsushima, Ikuo; Ogoshi, Masashi; Harada, Ichiro

2013-01-01

447

Issues in recycling and disposal of radioactively contaminated materials  

SciTech Connect

The Department of Energy`s present stock of potentially re-usable and minimally radioactively contaminated materials will increase significantly as the Department`s remediation activities expand. As part of its effort to minimize wastes, the Department is pursuing several approaches to recover valuable materials such as nickel, copper, and steel, and reduce the high disposal costs associated with contaminated materials. Key approaches are recycling radioactively contaminated materials or disposing of them as non-radioactive waste. These approaches are impeded by a combination of potentially conflicting Federal regulations, State actions, and Departmental policies. Actions to promote or implement these approaches at the Federal, State, or Departmental level involve issues which must be addressed and resolved. The paramount issue is the legal status of radioactively contaminated materials and the roles of the Federal and State governments in regulating those materials. Public involvement is crucial in the debate surrounding the fate of radioactively contaminated materials.

Kluk, A.F. [Dept. of Energy, Washington, DC (United States); Hocking, E.K. [Argonne National Lab., Washington, DC (United States); Roberts, R. [Dept. of Energy, San Francisco, CA (United States); Phillips, J.W. [Analytical Services, Inc., Columbia, MD (United States)

1993-10-01

448

Collection and Segregation of Radioactive Waste. Principals for Characterization and Classification of Radioactive Waste  

SciTech Connect

Radioactive wastes are generated by all activities which utilize radioactive materials as part of their processes. Generally such activities include all steps in the nuclear fuel cycle (for power generation) and non-fuel cycle activities. The increasing production of radioisotopes in a Member State without nuclear power must be accompanied by a corresponding development of a waste management system. An overall waste management scheme consists of the following steps: segregation, minimization, treatment, conditioning, storage, transport, and disposal. To achieve a satisfactory overall management strategy, all steps have to be complementary and compatible. Waste segregation and minimization are of great importance mainly because they lead to cost reduction and reduction of dose commitments to the personnel that handle the waste. Waste characterization plays a significant part in the waste segregation and waste classification processes, it implicates required waste treatment process including the need for the safety assessment of treatment conditioning and storage facilities.

Dziewinska, K.M.

1998-09-28

449

21 CFR 361.1 - Radioactive drugs for certain research uses.  

Code of Federal Regulations, 2011 CFR

... false Radioactive drugs for certain research uses. 361.1 Section 361.1 Food...EFFECTIVE AND NOT MISBRANDED: DRUGS USED IN RESEARCH § 361.1 Radioactive drugs for certain research uses. (a) Radioactive drugs...

2011-04-01

450

Evaluation of air effluent and workplace radioactivity monitoring at the Waste Isolation Pilot Plant.  

National Technical Information Service (NTIS)

Improvements are needed in the Waste Isolation Pilot Plant (WIPP) air effluent and workplace radioactivity monitoring prior to receipt of radioactive wastes. This report provides a detailed review Zf radioactivity air monitoring regulatory requirements an...

W. T. Bartlett

1993-01-01

451

21 CFR 361.1 - Radioactive drugs for certain research uses.  

Code of Federal Regulations, 2012 CFR

... false Radioactive drugs for certain research uses. 361.1 Section 361.1 Food...EFFECTIVE AND NOT MISBRANDED: DRUGS USED IN RESEARCH § 361.1 Radioactive drugs for certain research uses. (a) Radioactive drugs...

2012-04-01

452

21 CFR 361.1 - Radioactive drugs for certain research uses.  

... false Radioactive drugs for certain research uses. 361.1 Section 361.1 Food...EFFECTIVE AND NOT MISBRANDED: DRUGS USED IN RESEARCH § 361.1 Radioactive drugs for certain research uses. (a) Radioactive drugs...

2014-04-01

453

Process for Decontaminating Radioactive Waste Water Using a Ferrofluid and Magnetic Separation.  

National Technical Information Service (NTIS)

The present invention provides a process for decontaminating radioactive waste water containing a radioactive element that forms a water-insoluble compound. This process includes the steps of forming the compound of the radioactive element, treating the r...

G. L. Silver

1980-01-01

454

Radioactive material inventory control at a waste characterization facility  

SciTech Connect

Due to the recent introduction of more stringent Department of Energy (DOE) regulations and requirements pertaining to nuclear and criticality safety, the control of radioactive material inventory has emerged as an important facet of operations at DOE nuclear facilities. In order to comply with nuclear safety regulations and nuclear criticality requirements, radioactive material inventories at each nuclear facility have to be maintained below limits specified for the facility in its safety authorization basis documentation. Exceeding these radioactive material limits constitutes a breach of the facility`s nuclear and criticality safety envelope and could potentially result in an accident, cause a shut-down of the facility, and bring about imminent regulatory repercussions. The practice of maintaining control of radioactive material, especially sealed and unsealed sources, is commonplace and widely implemented; however, the requirement to track the entire radioactivity inventory at each nuclear facility for the purpose of ensuring nuclear safety is a new development. To meet the new requirements, the Applied Radiation Measurements Department at Oak Ridge National Laboratory (ORNL) has developed an information system, called the {open_quotes}Radioactive Material Inventory System{close_quotes} (RMIS), to track the radioactive material inventory at an ORNL facility, the Waste Examination and Assay Facility (WEAF). The operations at WEAF, which revolve around the nondestructive assay and nondestructive examination of waste and related research and development activities, results in an ever-changing radioactive material inventory. Waste packages and radioactive sources are constantly being brought in or taken out of the facility; hence, use of the RMIS is necessary to ensure that the radioactive material inventory limits are not exceeded.

Yong, L.K.; Chapman, J.A.; Schultz, F.J. [Oak Ridge National Laboratory, TN (United States)

1996-06-01

455

USING STATISTICAL PROCESS CONTROL TO MONITOR RADIOACTIVE WASTE CHARACTERIZATION AT A RADIOACTIVE FACILITY  

SciTech Connect

Two facilities for storing spent nuclear fuel underwater at the Hanford site in southeastern Washington State being removed from service, decommissioned, and prepared for eventual demolition. The fuel-storage facilities consist of two separate basins called K East (KE) and K West (KW) that are large subsurface concrete pools filled with water, with a containment structure over each. The basins presently contain sludge, debris, and equipment that have accumulated over the years. The spent fuel has been removed from the basins. The process for removing the remaining sludge, equipment, and structure has been initiated for the basins. Ongoing removal operations generate solid waste that is being treated as required, and then disposed. The waste, equipment and building structures must be characterized to properly manage, ship, treat (if necessary), and dispose as radioactive waste. As the work progresses, it is expected that radiological conditions in each basin may change as radioactive materials are being moved within and between the basins. It is imperative that these changing conditions be monitored so that radioactive characterization of waste is adjusted as necessary.

WESTCOTT, J.L.

2006-11-15

456

USING STATISTICAL PROCESS CONTROL TO MONITOR RADIOACTIVE WASTE CHARACTERIZATION AT A RADIOACTIVE FACILITY  

SciTech Connect

Two facilities for storing spent nuclear fuel underwater at the Hanford site in southeastern Washington State are being removed from service, decommissioned, and prepared for eventual demolition. The fuel-storage facilities consist of two separate basins called K East (KE) and K West (KW) that are large subsurface concrete pools filled with water, with a containment structure over each. The basins presently contain sludge, debris, and equipment that have accumulated over the years. The spent fuel has been removed from the basins. The process for removing the remaining sludge, equipment, and structure has been initiated for the basins. Ongoing removal operations generate solid waste that is being treated as required, and then disposed. The waste, equipment and building structures must be characterized to properly manage, ship, treat (if necessary), and dispose as radioactive waste. As the work progresses, it is expected that radiological conditions in each basin may change as radioactive materials are being moved within and between the basins. It is imperative that these changing conditions be monitored so that radioactive characterization of waste is adjusted as necessary.

WESTCOTT, J.L.; JOCHEN; PREVETTE

2007-01-02

457

Radioactive waste disposal implications of extending Part IIA of the Environmental Protection Act to cover radioactively contaminated land  

Microsoft Academic Search

A short study has been carried out of the potential radioactive waste disposal issues associated with the proposed extension of Part IIA of the Environmental Protection Act 1990 to include radioactively contaminated land, where there is no other suitable existing legislation. It was found that there is likely to be an availability problem with respect to disposal at landfills of

D. J. Nancarrow; M. M. White

2004-01-01

458

Directions in low-level radioactive waste management: A brief history of commercial low-level radioactive waste disposal  

SciTech Connect

This report presents a history of commercial low-level radioactive waste management 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 1980s to ensure the safe disposal of low-level waste in the 1990s and beyond. These steps include the issuance of Title 10 Code of Federal Regulations Part 61, Licensing Requirements for the Land Disposal of Radioactive Waste, the Low-Level Radioactive Waste Policy Act of 1980, the Low-Level Radioactive Waste Policy Amendments Act of 1985, and steps taken by states and regional compacts to establish additional disposal sites. 42 refs., 13 figs., 1 tab.

Not Available

1990-10-01

459

Hanford radioactive solid waste packaging, storage, and disposal requirements  

SciTech Connect

Westinghouse Hanford Company manages and operates the Hanford Site 200 Area radioactive solid waste storage and disposal facilities for the US Department of Energy-Richland Operations Office under contract AC06-87RL10930. These facilities include radioactive solid waste disposal sites and radioactive solid waste storage areas. This manual defines the requirements that must be met by waste generators for radioactive solid waste to be accepted by Westinghouse Hanford Company for storage or disposal at the 200 Area facilities. It is to be used by all waste generators preparing radioactive solid waste for storage or disposal at the Hanford Site facilities. This manual is also intended for use by Westinghouse Hanford Company solid waste technical staff involved with approval and acceptance of radioactive solid waste. Requirements in the manual represent a compilation of state and federal regulations, US Department of Energy Orders, Hanford Site requirements, and other rules, regulations, guidelines, and standards as they apply to storage or disposal of radioactive solid waste. Where appropriate, these requirements are included in the manual by reference. It is the intent of this manual to provide guidance to the waste generator in meeting the applicable requirements. 20 refs.

Stickney, R.G.

1988-09-01

460

Membrane Treatment of Liquid Salt Bearing Radioactive Wastes  

SciTech Connect

The main fields of introduction and application of membrane methods for preliminary treatment and processing salt liquid radioactive waste (SLRW) can be nuclear power stations (NPP) and enterprises on atomic submarines (AS) utilization. Unlike the earlier developed technology for the liquid salt bearing radioactive waste decontamination and concentrating this report presents the new enhanced membrane technology for the liquid salt bearing radioactive waste processing based on the state-of-the-art membrane unit design, namely, the filtering units equipped with the metal-ceramic membranes of ''TruMem'' brand, as well as the electrodialysis and electroosmosis concentrators. Application of the above mentioned units in conjunction with the pulse pole changer will allow the marked increase of the radioactive waste concentrating factor and the significant reduction of the waste volume intended for conversion into monolith and disposal. Besides, the application of the electrodialysis units loaded with an ion exchange material at the end polishing stage of the radioactive waste decontamination process will allow the reagent-free radioactive waste treatment that meets the standards set for the release of the decontaminated liquid radioactive waste effluents into the natural reservoirs of fish-farming value.

Dmitriev, S. A.; Adamovich, D. V.; Demkin, V. I.; Timofeev, E. M.

2003-02-25

461

The development of radioactive sample surrogates for training and exercises  

SciTech Connect

The development of radioactive sample surrogates for training and exercises Source term information is required for to reconstruct a device used in a dispersed radiological dispersal device. Simulating a radioactive environment to train and exercise sampling and sample characterization methods with suitable sample materials is a continued challenge. The Idaho National Laboratory has developed and permitted a Radioactive Response Training Range (RRTR), an 800 acre test range that is approved for open air dispersal of activated KBr, for training first responders in the entry and exit from radioactively contaminated areas, and testing protocols for environmental sampling and field characterization. Members from the Department of Defense, Law Enforcement, and the Department of Energy participated in the first contamination exercise that was conducted at the RRTR in the July 2011. The range was contaminated using a short lived radioactive Br-82 isotope (activated KBr). Soil samples contaminated with KBr (dispersed as a solution) and glass particles containing activated potassium bromide that emulated dispersed radioactive materials (such as ceramic-based sealed source materials) were collected to assess environmental sampling and characterization techniques. This presentation summarizes the performance of a radioactive materials surrogate for use as a training aide for nuclear forensics.

Martha Finck; Bevin Brush; Dick Jansen; David Chamberlain; Don Dry; George Brooks; Margaret Goldberg

2012-03-01