Sample records for u-series radioactive disequilibria

  1. U SERIES DISEQUILIBRIA: INSIGHTS INTO MANTLE MELTING AND THE TIMESCALES OF MAGMA

    E-print Network

    Jellinek, Mark

    U SERIES DISEQUILIBRIA: INSIGHTS INTO MANTLE MELTING AND THE TIMESCALES OF MAGMA DIFFERENTIATION] Several U series nuclides have half-lives (230 Th, 76 kyr; 231 Pa, 33 kyr; and 226 Ra, 1.6 kyr) comparable to timescales of magmatic processes. We review the basic principles of extracting time information from U series

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

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    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.

  4. Crustal overprint on mantle-derived U-series disequilibria in arc magmas: A warning signal from Volcán Llaima, Chile

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    U-series disequilibria provide important constraints on the processes and time scales of melt production, differentiation, and transport in subduction settings. Such constraints, that are essential for understanding the chemical evolution of the continental crust, are conventionally based on the assumption that the U-series disequilibria measured in mafic lavas are produced during mantle metasomatism and melting, and that intracrustal differentiation and assimilation have limited impacts. Petrological observations indicate, however, that assimilative recycling of partially to fully crystallized magmas left behind by previous phases of activity is common in arc magmatic systems. If the residence times of the assimilated magmas in the subvolcanic systems are comparable to the half-lives of U-series nuclides (1.6-76 k.y.), this process may significantly overprint mantle-derived disequilibria. Our work on mafic lavas erupted at Volcán Llaima, Chile establishes a well documented example of the consequences of crustal overprinting on the basis of multiple historic eruptions from one volcano and indicates that the rates of material transport beneath arcs obtained from U-series disequilibria may need to be partially reconsidered. Basaltic andesitic lavas erupted at Volcán Llaima, Andean Southern Volcanic Zone (SVZ) of Chile since 1640 are characterized by 238U, 231Pa, and 226Ra excesses typical of arc magmas. These data define linear correlations between 238U and 231Pa excesses and LILE/HFSE and LREE/HFSE ratios. Variations in U-series disequilibria within single eruptions cover up to 66% of the total range and are significant compared to the global variability in arc magmas. Chemical modeling demonstrates that the correlated U-series arrays can not be produced by mantle metasomatism and/or partial melting. The observed spatial and temporal variability in U-series disequilibria is, however, consistent with assimilation of 5-20% of dioritic to granodioritic rocks that form Llaima’s subvolcanic basement (the Neogene plutonic roots of the arc). This model reproduces Pa-U-Th disequilibria, Nd isotope, and incompatible trace element ratio arrays. Mixing between the “contaminated” basaltic andesitic magmas with young (several kyr old) intermediate crystal mush additionally affects the trace element contents and 226Ra excesses of the magma erupted during flank eruptions. The Llaima case demonstrates that assimilation of ancestral magmas in the upper crust can produce inclined U-Th isotope arrays and positively correlated (238U/230Th), (226Ra/230Th), and Ba/Th trends which could easily be mistaken as slab-fluid indicators and chronometers, or tracers of sediment recycling in subduction zone. Assimilative recycling of aged plutonic roots of arc volcanoes is likely to be widespread, but is difficult to monitor due to low Nd-Sr-Pb isotopic contrast. Crustal filtering of mantle-derived U-series disequilibria needs to be carefully evaluated.

  5. Evaluation of Mantle Upwelling Beneath Iceland from U-series Disequilibria: Implication for Icelandic Mantle Plume Dynamics

    NASA Astrophysics Data System (ADS)

    Chekol, T. A.; Kobayashi, K.; Nakamura, E.

    2009-05-01

    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 provide a relative measure of mantle upwelling velocity beneath ocean islands(e.g. Sims, et al., 1999; Kokfelt, et al., 2003; Bourdon, et al., 2005). 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 to 12 cm per year towards the presumed center of Iceland plume, but after about 135 km from the center of the plume the upwelling rates remain constant (2-3 cm per year). We suggest that the incremental upwelling rates towards the center can be 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.

  6. Source versus differentiation controls on U-series disequilibria: Insights from Cotopaxi Volcano, Ecuador

    E-print Network

    ) values of 0.96­1.07 in andesites can be explained by several potential processes, including melting and assimilation to account for the range of U-series data in the Cotopaxi andesites. Mantle like 87 Sr/86 Sr. On the basis of the 238 U­230 Th­226 Ra data, the time for assimilation and ascent of the andesites was

  7. Examining Canonical Theories of U-series Disequilibria in Volcanic Arcs in Light of a More Comprehensive, Global Database

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    Disequilibrium in the short-lived U-series isotopic system occurs during partial melting, differentiation, and volatile transport; therefore, the U-series decay chain is a unique tool to examine the magnitude and timing of magmatic processes. However, our understanding of U-series fractionation in subduction zones is incomplete. We use published data from volcanoes around the world and new data from volcanic systems in the Kamchatka Arc (Bezymianny, Klyuchevskoy, and Karymsky) to examine two theories regarding the behavior of U-series nuclides: 1) that Th-excess in arc magmas, (230Th)/(238U) >1, is a function of arc-thickness/garnet in the melting region, or magnetite fractionation and 2) that 210Pb deficits, (210Pb)/(226Ra) <1, are the result of continuous magma degassing. Our results show that neither of these theories explains the complete dataset produced by the U-series community. Th-excess is generally observed in MORB and attributed to decompression melting; however, global data also record Th-excess in fluid-fluxed subduction zones. Limited experimental data suggest preferential U transport over Th in subduction zone fluids and, therefore, U-excess rather than Th-excess should exist in arcs. The common explanation for arc Th-excess is melt interaction with thick continental crust where phases such as garnet retain high U/Th in crystalline residues. We record Th-excess at Bezymianny, (230Th)/(238U) from 1.04-1.06 and Klyuchevskoy, (230Th)/(238U) from 1.01 and 1.08, volcanoes, which are located on relatively thin (~35 km), primitive crust. These magmas have low Sr/Y (15.5-19.9) that preclude a significant influence of garnet. In addition, LA-ICP-MS measurements of in-situ U and Th mineral-melt partitioning on erupted mineral phases (plagioclase, pyroxene, Fe-Ti oxides, apatite) suggest that U-series disequilibria are transparent to shallow crustal processing. Th-excess at Klyuchevskoy inversely correlates with Ba/Th, Sr/Th, Dy/Yb, and Ce/Pb. We suggest that Th-excess is a function of decompression mantle melting beneath arcs and/or phase fractionation by lower crustal mineral assemblages. 210Pb deficits are interpreted as the result of 222Rn gas loss in magmatic systems. With 222Rn loss, the daughter product, 210Pb, cannot grow into magma. Two published models (Gauthier and Condomines 1999 and Condomines et al. 2010) simulate this process where the magnitude of 210Pb deficit increases with the duration of degassing. We record 210Pb deficits at Bezymianny and Karymsky volcanoes (0.846-0.966). However, for known eruption intervals, these 210Pb deficits are larger than current models predict. If physical constraints for gas behavior in magma are added to these models, the problem is magnified. Our results highlight a need for studies quantifying the fractionation of U-series nuclides among all phases (crystals, melts, and volatiles) relevant to subduction zones. Primitive, thin volcanic arcs that have a well-characterized volcanic history through time, similar to the Kamchatka Arc, are ideal places to begin.

  8. 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...

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

    NASA Astrophysics Data System (ADS)

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

    2005-05-01

    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).

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

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

    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.

  11. Recycling of crystal mush-derived melts and short magma residence times revealed by U-series disequilibria at Stromboli volcano

    NASA Astrophysics Data System (ADS)

    Bragagni, Alessandro; Avanzinelli, Riccardo; Freymuth, Heye; Francalanci, Lorella

    2014-10-01

    The presence of crystal mushes in the feeding system of active volcanoes is generally revealed by antecrysts, representing the crystalline portion of old magmas recycled in the juvenile material, but very little is known about the fate of interstitial liquid hosted within the crystal-rich mush (i.e. antemelt). U-series disequilibria measured in magmas erupted in the past 18 years at Stromboli volcano provide the first geochemical evidence of the involvement of antemelt and help constraining the timescales of the processes occurring in the plumbing system of the volcano. Despite almost constant major and trace element composition, significant variations in isotope ratios are observed. (230Th/232Th) decreases with time, whilst (238U/232Th), (226Ra/230Th) and 87Sr/86Sr are different in the two types of magma erupted. Magma with low phenocryst content (lp) is erupted as pumices during paroxysm and is thought to belong to a deep reservoir. Highly porphyritic magma (hp) is erupted during the normal “Strombolian” activity as scoria and during the effusive events as lavas, and it is considered to derive from the former one within a shallow reservoir through degassing-driven crystallisation, mixing and incorporation of antecrysts. The distinct (238U/232Th) of lp and hp magma requires the involvement of a component with high 87Sr/86Sr and (238U/232Th) deriving from older magmas erupted earlier in the volcano history (up to 2.5 ka). The incompatibility of U and Th in major mineral phases limits the possible effect of antecrysts, hence requiring the involvement of a U- and Th-rich antemelt. The decrease of 226Ra-excess from lp to hp magmas provides further and independent evidence for the involvement of a few thousands years old antemelt. The variation with time of (230Th/232Th) within lp and hp magmas is exploited to constrain the residence time of magmas in the deep and shallow reservoir of the volcano to <55 yrs (inferred reservoir volume <0.5 km) and 2-10 yrs (inferred reservoir volume 0.02-0.09 km), respectively. Our results show the occurrence of magmatic processes operating at different timescale within the feeding system of a so-called steady state volcano, such as Stromboli. We show that, while most of the magma is erupted within few years, a portion of it, made of both crystals (antecrysts) and residual liquid (antemelt), can be stored in the plumbing system for thousands of years to be eventually rejuvenated and mixed back into the shallow reservoir. The presence of antemelts may also affect the eruptive mechanism by promoting heat transfer in locked crystal mushes, hence favouring their remobilisation.

  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)

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

    2010-05-01

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

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

    Microsoft Academic Search

    C. T. Donnelly; K. M. Cooper

    2005-01-01

    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

  14. A New Model for U-Series Isotope Fractionation During Igneous Processes, With Finite Diffusion and Multiple Solid Phases

    NASA Astrophysics Data System (ADS)

    van Orman, J.; Saal, A.; Bourdon, B.; Hauri, E.

    2002-12-01

    U-series radioactive disequilibria in basaltic lavas have been used to infer many important aspects of melt generation and extraction processes, including the porosity of the melting zone, the mantle upwelling rate, and the melt transport rate. These inferences are based on simplified models for the fractionation of U-series isotopes during melting and melt transport. The commonly used "dynamic melting" and "equilibrium porous flow" models neglect solid-state diffusion and do not consider the influence of multiple solid phases on the initial distribution and subsequent fractionation of U-series isotopes. These factors can be very important, particularly for 226Ra which has a short half-life (~1600 yrs) and is strongly partitioned into minerals like plagioclase, amphibole, and mica while being almost perfectly excluded from clinopyroxene and garnet, the major U and Th bearing minerals in peridotite. Ignoring diffusion and multi-phase effects can lead to conclusions about the melting process that have no basis in reality. We have developed a numerical model that takes into account the effects of solid-state diffusion and considers the distribution of U-series isotopes among multiple solid phases and melt at each step of the melting process. In an undisturbed rock in secular equilibrium, daughter isotopes will tend to be transferred among the component phases until they reach a steady state in which diffusive fluxes are balanced by radioactive production and decay. In general the individual minerals will be neither in secular equilibrium (on the equiline) nor in partitioning equilibrium with each other (on a horizontal line on the equiline diagram), unless diffusion is very slow or very fast relative to the daughter decay rate. We start with an arbitrary distribution of daughter isotopes among the phases in the system, then turn on diffusion and allow isotopes to redistribute themselves until the steady state is reached (on a time scale comparable to the half-life of the isotope). Next, partial melting begins, or a foreign melt is introduced into the system, and isotopes are again redistributed among the phases via diffusion. U-series isotopes can be strongly fractionated during this stage due to differences in diffusivity. The diffusive fractionation can be much larger than equilibrium fractionation, and may even be in the opposite sense. We performed a series of calculations to simulate interaction of MORB liquids with "old" cpx+plag bearing gabbro in bulk secular equilibrium. In the gabbro at steady state, most of the U and Th reside in the cpx, and most of the 226Ra resides in the plagioclase. Because Ra diffusion in plagioclase is much faster than Th diffusion in cpx, large fractionations of 226Ra and 230Th can take place. If the MORB is more depleted than a melt that would be in equilibrium with the gabbro, then it acquires excess 226Ra; if it is more enriched, it acquires a 226Ra deficit. Interaction with gabbros will tend to produce large Ra excesses in D-MORB (> 5), but small Ra excesses (or even Ra deficits) in E-MORB. This is consistent with observations, and suggests that 226Ra-230Th disequilibria in MORB can be explained by shallow-level processes, and may give no information on processes of mantle melting.

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

    Microsoft Academic Search

    C. Donnelly; K. M. Cooper

    2006-01-01

    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

  16. Sampling Theory for Cytonuclear Disequilibria

    PubMed Central

    Asmussen, M. A.; Basten, C. J.

    1994-01-01

    We examine the statistical properties of cytonuclear disequilibria within a system including one diploid nuclear locus and one haploid cytoplasmic locus, each with two alleles. The results provide practical guidelines for the design and interpretation of cytonuclear surveys seeking to utilize the novel evolutionary information recorded in the observed pattern of cytonuclear associations. Important applications include population studies of nuclear allozymes in conjunction with genes from mitochondria, chloroplasts, or cytoplasmically inherited microorganisms. Our attention focuses on the allelic and genotypic disequilibria, which respectively measure the nonrandom associations between the cytotypes and the nuclear alleles and genotypes. We first derive the maximum likelihood estimators and their approximate large sample variances for each disequilibrium measure. These are each in turn used to set up an asymptotic test of the null hypothesis of no disequilibrium. We then calculate the minimum sample sizes required to detect the disequilibria under specified alternate hypotheses. The work also incorporates the deviation from Hardy-Weinberg equilibrium at the nuclear locus, which can significantly affect the results. The practical utility of this new sampling theory is illustrated through applications to two nuclear-mitochondrial data sets. PMID:7896114

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

    SciTech Connect

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

    1999-07-01

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

  18. Timescales of magma degassing - Insights from U-series disequilibria, Mount Cameroon, West Africa

    NASA Astrophysics Data System (ADS)

    Turner, M. B.; Reagan, M. K.; Turner, S. P.; Sparks, R. S. J.; Handley, H. K.; Girard, G.; Suh, C. E.

    2013-07-01

    Short-lived uranium-series isotope data from rocks erupted under explosive and effusive regimes are presented and used to provide constraints on the timescales of magmatic degassing and volatile fluxing during the 1999 and 2000 AD eruption of Mt. Cameroon. In contrast to the relatively homogenous major and trace element data of the analysed rocks, volcanic rocks from Mt. Cameroon reveal a spread of 230Th-226Ra isotope data. Volcanic rocks erupted along the southwest rift in 1999 have (226Ra/230Th) ratios of ~ 1.25, whereas rocks erupted more axially in 2000 have relatively low (226Ra/230Th) ratios of 1.09-1.2 and concomitant low Ba/Th ratios. These differences imply separate magma chamber systems and probably reflect differences in the concentrations of water within the primary magmas, which led to different amounts of amphibole fractionation at depth. Variations in the (210Pb/226Ra)0 ratios are used to track degassing or volatile accumulation within the magma system. The near equilibrium (210Pb/226Ra) values for effusively erupted rocks from Mt. Cameroon suggest that this magma resided for more than several decades and less than a few thousand years before it erupted. The small excesses of 210Pb over 226Ra in some samples indicate that some of this magma was fluxed by a Rn-bearing gaseous phase for weeks to years before the eruption. In contrast, most explosively erupted rocks from Mt. Cameroon have deficits of 210Pb relative to 226Ra that require years to decades of degassing before eruption. We suggest that the magmas erupted as scoria at Mt. Cameroon degassed as they rose from lithospheric depths. Deep degassing was CO2-dominated, whereas shallower magma degassing involved more water and crystallisation of an anhydrous mineral assemblage.

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

    NASA Astrophysics Data System (ADS)

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

    2003-04-01

    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.

  20. Uranium and thorium decay series disequilibria in young volcanic rocks

    SciTech Connect

    Williams, R.W.

    1988-01-01

    Two of the central questions in igneous geochemistry that study of radioactive disequilibria can help to answer are: what are the rates of magma genesis; and what are the timescales of magma separation and transport. In addition to the temporal information that may be extracted from disequilibria data, the {sup 230}Th/{sup 232}Th of a young rock may be used as a tracer of the Th/U ratio of its source region. Measurements were made by isotope dilution alpha-spectrometry of {sup 238}U, {sup 234}U, {sup 230}Th, and {sup 232}Th in 20 subduction related, 3 oceanic intraplate, and 10 continental intraplate volcanics. {sup 210}Pb was measured in all, {sup 226}Ra was measured in about half, and {sup 228}Th was measured in 10 of the most recent samples. Disequilibrium between {sup 228}Th and {sup 232}Th was found only in the Nacarbonatite samples from Oldoinyo Lengai volcano in Tanzania, which is attributable to {sup 228}Ra/{sup 232}Th {approximately} 27 at the time of eruption. These rocks also have {sup 226}Ra/{sup 230}Th > 60. Three Ra-enrichment models are developed which constrain carbonatite magma formation at less than 20 years before eruption. The effects of different partial melting processes on the {sup 238}U decay series are investigated. If mid-ocean ridge basalts are formed by a dynamic melting process, the {sup 230}Th/{sup 232}Th of the basalts provides a minimum estimate of the Th/U ratio of the source region. The {sup 238}U enrichment in arc volcanics is probably the results of metasomatism of the source by fluids derived from the subducting slab, and the {sup 230}Th enrichment observed for other volcanics is probably due to the partial melting process in the absence of U-bearing fluids.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Magmas erupted from subduction zone volcanoes represent the end products of multiple magmatic processes occurring in the asthenospheric mantle wedge and overlying lithosphere (i.e., fluid addition, melting, assimilation, and crystal fractionation). To resolve the contributions of diverse processes and components, and the relative timing of these events, we have determined U-series activities (U-Th-Ra-Pa) for 60 and 10Be compositions for 20 historic or very young lavas carefully chosen on the basis of major and trace element analyses of 625 samples from six volcanoes in the Andean Southern Volcanic Zone of Chile (37.6-41.1°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.

  2. Integration of U-Series and Os Isotopic Data From the Azores: Insights Into Processes Controlling the Generation and Transport of Melt Within the Mantle beneath Ocean Island Volcanoes

    NASA Astrophysics Data System (ADS)

    Schaefer, B. F.; Turner, S. P.

    2006-12-01

    We observe broad correlations between U-series (specifically Th- and Ra disequilibria) isotopes and the spatial variations in likely melt source isotopic domains defined by Os isotopes beneath the Azores archipelago. More specifically, the central islands of the archipelago (Faial, Terceira and Sao Jorge); which preserve a previously reported unradiogenic (subchondritic) Os isotopic component also record correlated Os- U-series disequilibria, implying that the compositional variation at depth beneath the centre of the plume is exerting some control on melt generation and extraction processes. Significantly, simple diffusive transfer modelling suggests that in order to preserve such highly unradiogenic Os isotopic signatures through the melting process to the surface, a rapid transition from porous flow of melts through asthenospheric mantle to channel flow must take place. The length scale for this transition must be of the order of millimetres. If porous flow was dominant for longer length scales, then we would predict that the highly unradiogenic Os isotopic signature would rapidly become homogenesied with that of the surrounding asthenospheric mantle. Ra disequilibria suggest that this is likely to occur on time scales of between 100- 1000 years.

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

    SciTech Connect

    Zou, H.; Zindler, A.

    2000-05-01

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

  4. The U-series toolbox for paleoceanography Gideon M. Henderson

    E-print Network

    Henderson, Gideon

    1 The U-series toolbox for paleoceanography Gideon M. Henderson Department of Earth Sciences the past environment. Of the many measurements that provide such information, those of the U to are those provided by cosmogenic nuclides (principally 14 C) or the U-series nuclides. This makes the U

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  6. Quantifying trace element disequilibria in mantle xenoliths and abyssal peridotites

    E-print Network

    Lee, Cin-Ty Aeolus

    Quantifying trace element disequilibria in mantle xenoliths and abyssal peridotites Arnaud Agranier in mantle xenoliths and abyssal peridotites using in situ analytical tools. Even when only mineral cores in mantle xenoliths are closer to equilibrium than those in abyssal peridotites even though mantle xenoliths

  7. 234Th:238U disequilibria within the California Current

    Microsoft Academic Search

    KENNETH H. COALE; KENNETH W. BRULAND

    1985-01-01

    Profiles of dissolved and particulate 234Th were determined at several stations within the Cali- fornia Current. Modeling of the disequilibria between the 234Th and 23aU within the surface waters provides for estimates of the residence time of dissolved thorium with respect to particle scavenging (TP varies from 6 to 50 days), the particle residence time (TP varies from 2 to

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

    SciTech Connect

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

    1987-12-01

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

  9. Mantle melting and magma supply to the Southeast Indian Ridge: The roles of lithology and melting conditions from U-series disequilibria

    E-print Network

    Graham, David W.

    of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331 USA b School of Ocean in axial morphology and axial magma chamber depth, and systematic long wavelength geochemical gradients-ocean ridges (MORs) are indirect probes of upper mantle composition and melting conditions. Geographic

  10. Atmospheric dust contribution to budget of U-series nuclides in weathering profiles. The Mount Cameroon volcano

    NASA Astrophysics Data System (ADS)

    Pelt, E.; Chabaux, F. J.; Innocent, C.; Ghaleb, B.

    2009-12-01

    Analysis of U-series nuclides in weathering profiles is developed today for constraining time scale of soil and weathering profile formation (e.g., Chabaux et al., 2008). These studies require the understanding of U-series nuclides sources and fractionation in weathering systems. For most of these studies the impact of aeolian inputs on U-series nuclides in soils is usually neglected. Here, we propose to discuss such an assumption, i.e., to evaluate the impact of dust deposition on U-series nuclides in soils, by working on present and paleo-soils collected on the Mount Cameroon volcano. Recent Sr, Nd, Pb isotopic analyses performed on these samples have indeed documented significant inputs of Saharan dusts in these soils (Dia et al., 2006). We have therefore analyzed 238U-234U-230Th nuclides in the same samples. Comparison of U-Th isotopic data with Sr-Nd-Pb isotopic data indicates a significant impact of the dust input on the U and Th budget of the soils, around 10% for both U and Th. Using Sr-Nd-Pb isotopic data of Saharan dusts given by Dia et al. (2006) we estimate U-Th concentrations and U-Th isotope ratios of dusts compatible with U-Th data obtained on Saharan dusts collected in Barbados (Rydell H.S. and Prospero J.M., 1972). However, the variations of U/Th ratios along the weathering profiles cannot be explained by a simple mixing scenario between material from basalt and from the defined atmospheric dust pool. A secondary uranium migration associated with chemical weathering has affected the weathering profiles. Mass balance calculation suggests that U in soils from Mount Cameroon is affected at the same order of magnitude by both chemical migration and dust accretion. Nevertheless, the Mount Cameroon is a limit case were large dust inputs from continental crust of Sahara contaminate basaltic terrain from Mount Cameroon volcano. Therefore, this study suggests that in other contexts were dust inputs are lower, or the bedrocks more concentrated in U and Th, the dust contribution will not significantly influence U-series dating. Chabaux F., Bourdon B., Riotte J. (2008). U-series Geochemistry in weathering profiles, river waters and lakes. Radioactivity in the Environment, 13, 49-104. Dia A., Chauvel C., Bulourde M. and Gérard M. (2006). Eolian contribution to soils on Mount Cameroon: Isotopic and trace element records. Chem. Geol. 226, 232-252. Rydell H.S. and Prospero J.M. (1972). Uranium and thorium concentrations in wind-borne Saharan dust over the western equatorial north atlantic ocean. EPSL 14, 397-402.

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

    NASA Astrophysics Data System (ADS)

    Zolotov, M. Y.

    2010-12-01

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

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

    PubMed

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

    2014-05-01

    The spatial distribution of (238)U-series radionuclides, specifically 238U, 234U, 230Th and 226Ra, 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 234U/238U, 230Th/238U and 226Ra/238U were used to determine the degree of radioactive disequilibrium. The data show disequilibrium in most of the sediments, with activity ratios of 234U/238U, 230Th/238U and 226Ra/238U>1, inconsistent with evolution through straightforward weathering processes. Multivariate cluster analysis based on five variables, the specific activities of 238U, 234U, 230Th, 226Ra 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

  13. Modeling U-Series Concordia/Discordia Using STELLA

    NSDL National Science Digital Library

    Kirsten Menking

    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.

  14. Upwelling Rates Beneath Hotspots : Evidence From U-Series in Basalts From the Mid-Atlantic Ridge and the Azores Islands

    NASA Astrophysics Data System (ADS)

    Bourdon, B. P.; Turner, S. P.

    2001-12-01

    In this study, we have analyzed U-series in lavas from the Azores islands and the nearby Mid-Atlantic Ridge (FAZAR cruise) in an attempt to assess the relative importance of melting processes versus source variations in the context of ridge-hotpsot interaction. The lavas were analyzed for 238U-230Th (Turner et al. 1997, Bourdon et al. 1996) 226Ra-230Th and 235U-231Pa disequilibria by thermal ionisation mass spectrometry. Our results for the historic lavas from the Azores islands show that the 231Pa excess are at the low end of the trend found for other OIB (Pickett et al. 1997 and Bourdon et al. 1998) and fall on a positive correlation in a 231Pa/235U versus 230Th/238U diagram. In contrast, lavas from the nearby Mid-Atlantic ridge are characterized by larger (231Pa/235U) activity ratios for similar and greater (230Th/238U) ratios. There is also a weak correlation between 226Ra/230Th and 231Pa/235U. These data do not indicate a simple mixing trend between an N-MORB and an enriched component in the 231Pa/235U versus 230Th/238U diagram since the MORBs which do not have the most radiogenic isotope signatures compared with the Azores island basalts have some of the largest (230Th/238U) and 231Pa/235U. Clearly, the dynamics of melting must have played a role in generating larger 230Th and 231Pa excesses beneath the Mid-Atlantic ridge. We infer that this must be due to the absence of a lithospheric lid as larger excesses of 230Th and 231Pa can be generated for longer melting columns. Thus, ridge-hotspot interaction cannot imply a simple transfer of melt from the hotspot to the ridge. The 230Th/238U and 226Ra/230Th data across the Azores plateau shows a maximum for the island of Terceira and mimics the depth anomaly which is thought to result from the hotspot. This trend is also consistent with observations of rare gases (M. Moreira pers. comm.) and suggests that it must be related to the presence of deep material. The U-series trend is the reverse of the trend found in Hawaii by Sims et al. (2000) which was attributed to variations in upwelling rates across the rising plume. This observation can be rationalized in the context of an equilibrium melt transport model (Spiegelman and Elliott, 1993) where U-series disequilibria are sensitive to upwelling rates. For slow upwelling rates such as below the Azores, larger 230Th excesses are predicted in the center of the plume. This suggests that the upwelling rate beneath the center of the plume must be of the order of a few cm per year which is an order of magnitude lower than values estimated for Hawaii. Turner et al. 1997, Chem. Geol. 139, 145-164. Bourdon et al. 1996, Earth Planet. Sci. Lett. 142, 175-189. Pickett et al. 1997, Earth Planet. Sci. Lett. 148, 259-271. Sims et al. 1999, Geochim. Cosmochim. Acta. 63, 4119-4138. Spiegelman and Elliot, 1993, Earth Planet. Sci. Lett., 118, 1-20.

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

    USGS Publications Warehouse

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

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Donnelly, C.; Cooper, K. M.

    2006-12-01

    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 Mt. St. Helens have demonstrated a complex growth history recorded by a disparity in 226Ra-230Th and 230Th-238U crystal ages. In order to unwind this history, we are analyzing several size fractions of plagioclase crystals to be used as proxies for distinct crystal populations. Preliminary U-Th data indicate that each size fraction is influenced to varying degrees by the presence of a third component characterized by an anomalously low 230Th/232Th isotopic signature. Each population also appears to contain a small fraction of zero-age material, consistent with an episode of renewed crystallization immediately prior to eruption. MSH304 plagioclase (erupted Oct. 2004), has a Th IC significantly lower than any MSH samples previously analyzed and differs greatly from its corresponding whole rock, indicating that either this plagioclase was dominated by crystals foreign to the matrix within which they were erupted, or that they are tens of thousands of years old. Our research will demonstrate the potential for using U-series nuclides to analyze the crystallization history of magmatic bodies and allow us to monitor changes in the subsurface material being tapped by the eruption.

  17. Oceanic stratified euphotic zone as elucidated by 234Th : 238U disequilibria

    Microsoft Academic Search

    KENNETH H. COALE; KENNETH W. BRULAND

    1987-01-01

    Profiles of dissolved and particulate 234Th were determined at the VERTEX 2 and 3 stations off Manzanillo, Mexico, and at the VERTEX 4 station about 900 km north of Hawaii. By modeling the disequilibria between 234Th and 238U in the dissolved and particulate form, estimates of scav- enging rates for Th from the dissolved to particulate phases, particle residence times,

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

    PubMed

    Lowe, L M

    1997-10-01

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

  19. Disequilibrium of the 238U series in basalt

    USGS Publications Warehouse

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

    1966-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

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

    Microsoft Academic Search

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

    2008-01-01

    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

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

    Microsoft Academic Search

    J. L. Bischoff; J. A. Fitzpatrick

    1991-01-01

    U-series dating is a well-established technique for age determination of Late Quaternary carbonates. Materials of sufficient purity for nominal dating, however, are not as common as materials with mechanically inseparable aluminosilicate detritus. Detritus contaminates the sample with extraneous Th. The authors propose that correction for contamination is best accomplished with the isochron technique using total sample dissolution (TSD). Experiments were

  3. Primary U distribution in scleractinian corals and its implications for U series dating

    Microsoft Academic Search

    Laura F. Robinson; Jess F. Adkins; Diego P. Fernandez; Donald S. Burnett; S.-L. Wang; Alexander C. Gagnon; Nir Krakauer

    2006-01-01

    In this study we use microsampling techniques to explore diagenetic processes in carbonates. These processes are important as they can affect the accuracy of U series chronometry. Fission track maps of deep-sea scleractinian corals show a threefold difference between the minimum and maximum [U] in modern corals, which is reduced to a factor of 2 in fossil corals. We use

  4. Carbon Export in Coastal NW Mediterranean Sea: Sediment Trap Records and 234Th:238U Disequilibria Modelling

    NASA Astrophysics Data System (ADS)

    Miquel, J.; Laurent, E. N.; Fowler, S. W.; Cochran, K.

    2001-12-01

    Sediment traps have been widely used over the past 30 years to study the downward flux of particles in various environmental conditions. They are a unique tool to measure particle flux in the water column and for collecting samples to estimate fluxes of a variety of elements and compounds. Also, they permit recording fluxes over long periods of time to observe seasonal and annual changes in sedimentation. It is widely accepted that traps deployed in calm environments or the deep ocean provide a reasonable estimate of in-situ sedimentation. The situation is not always the same when traps are deployed in high energy environments or shallow waters. Trap data obtained under the latter conditions may present hydrodynamic bias. Since the activity of 234Th in the oceans is primarily controlled by production from its soluble parent 238U and losses through radioactive decay plus sorptive removal on sinking particles, the accuracy of trap measurements in shallow waters can be verified by studying the 234Th:238U disequilibria in water. From the 234Th deficiency one can predict the 234Th flux down to the depth of disequilibrium. Given this and 234Th measurement in the traps, one can learn independently if traps are collecting 234Th -bearing particles in a predictable fashion. In a similar way, carbon fluxes can be predicted by using experimentally determined C to Th ratios. During spring, a field intercomparison of the 3 Technicap models of sediment traps was carried out off Monaco. During one month the traps were deployed at 170m depth on 3 independent moorings over a bottom of 370m depth. Currents were also recorded during the entire period of the experiment. In order to relate the measured fluxes to changes in the environment, the water column was sampled weekly for basic physico-chemical parameters such as temperature, salinity, fluorescence, chlorophyll a and particulate organic carbon. Concomitantly, particulate and dissolved 234Th were measured in the water column using in-situ large volume pumps in order to compare 234Th trap-measured fluxes with fluxes predicted based on 234Th-deficiency, and to estimate carbon fluxes from 234Th:238U disequilibria and C/234Th ratios in the sinking particles. Fluxes measured by the 3 sediment traps were in good agreement during most of the sampling period. Only during periods of high sedimentation did the measured fluxes present a high variability between traps but without any consistent differences for any given model. Similar trends were observed for carbon fluxes and, to a lesser extent, for pigment fluxes. 234Th trap-measured fluxes displayed the same time-related pattern but were more variable in-between traps. On a weekly base, 234Th trap-measured fluxes and predicted 234Th fluxes based on 234Th-deficiency presented important discrepancies but, fluxes integrated over the entire experiment were relatively similar. These results suggest that both approaches lead to closer estimates of 234Th and carbon fluxes when periods of a few weeks are taken into consideration.

  5. Modeling of U-series Radionuclide Transport Through Soil at Pena Blanca, Chihuahua, Mexico

    NASA Astrophysics Data System (ADS)

    Pekar, K. E.; Goodell, P. C.; Walton, J. C.; Anthony, E. Y.; Ren, M.

    2007-05-01

    The Nopal I uranium deposit is located at Pena Blanca in Chihuahua, Mexico. Mining of high-grade uranium ore occurred in the early 1980s, with the ore stockpiled nearby. The stockpile was mostly cleared in the 1990s; however, some of the high-grade boulders have remained there, creating localized sources of radioactivity for a period of 25-30 years. This provides a unique opportunity to study radionuclide transport, because the study area did not have any uranium contamination predating the stockpile in the 1980s. One high-grade boulder was selected for study based upon its shape, location, and high activity. The presumed drip-line off of the boulder was marked, samples from the boulder surface were taken, and then the boulder was moved several feet away. Soil samples were taken from directly beneath the boulder, around the drip-line, and down slope. Eight of these samples were collected in a vertical profile directly beneath the boulder. Visible flakes of boulder material were removed from the surficial soil samples, because they would have higher concentrations of U-series radionuclides and cause the activities in the soil samples to be excessively high. The vertical sampling profile used 2-inch thicknesses for each sample. The soil samples were packaged into thin plastic containers to minimize the attenuation and to standardize sample geometry, and then they were analyzed by gamma-ray spectroscopy with a Ge(Li) detector for Th-234, Pa-234, U-234, Th-230, Ra-226, Pb-214, Bi-214, and Pb-210. The raw counts were corrected for self-attenuation and normalized using BL-5, a uranium standard from Beaverlodge, Saskatchewan. BL-5 allowed the counts obtained on the Ge(Li) to be referenced to a known concentration or activity, which was then applied to the soil unknowns for a reliable calculation of their concentrations. Gamma ray spectra of five soil samples from the vertical profile exhibit decreasing activities with increasing depth for the selected radionuclides. Independent multi-element analyses of three samples by ICP-MS show decreasing uranium concentration with depth as well. The transport of the radionuclides is evaluated using STANMOD, a Windows-based software package for evaluating solute transport in porous media using analytical solutions of the advection-dispersion solute transport equation. The package allows various one-dimensional, advection-dispersion parameters to be determined by fitting mathematical solutions of theoretical transport models to observed data. The results are promising for future work on the release rate of radionuclides from the boulder, the dominant mode of transport (e.g., particulate or dissolution), and the movement of radionuclides through porous media. The measured subsurface transport rates provide modelers with a model validation dataset.

  6. Mass spectrometric U-series dating of Laibin hominid site in Guangxi, southern China

    Microsoft Academic Search

    Guanjun Shen; Wei Wang; Hai Cheng; R. Lawrence Edwards

    2007-01-01

    The Laibin hominid represents one of the rare finds of modern Homo sapiens in China, rare for its relative completeness and well-established stratigaphic provenance. This paper presents the results of mass spectrometric U-series dating of intercalated calcite samples from the Laibin site. The capping flowstone and the calcite vein, which sandwich the hominid fossil-containing deposits, date to 38.5±1.0 and 44.0±0.8ka,

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

    PubMed Central

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

    2000-01-01

    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. PMID:10757775

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

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

    PubMed

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

    2013-05-01

    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

  10. Use of U-Series Isotopic Disequilibrium to Investigate the Nature and Distribution of Actively Flowing Fractures

    NASA Astrophysics Data System (ADS)

    Nichols, P. J.; Paces, J. B.; Neymark, L. A.; Rajaram, H.

    2011-12-01

    Groundwater transport of radioisotopes from underground nuclear tests at the Nevada National Security Site (NNSS) is of concern to the U.S. Department of Energy. Extensive testing was conducted near or below the regional water table (saturated zone; SZ) at Pahute Mesa and within the unsaturated (or partially saturated) zone at Rainier Mesa. Groundwater flow in these rocks is believed to occur mainly through a connected network of fractures. To better understand flow in these fractured rocks, we analyzed U-series isotopes (238U-234U-230Th) from drill core samples. In rock isolated from flow over the last million years, isotopes in the 238U decay chain reach a state of radioactive secular equilibrium, where 234U/238U and 230Th/238U activity ratios (AR) = 1.0. More recent water-rock interaction results in mobilization of 234U relative to 238U, and U relative to Th in migrating waters. Rock surfaces that incorporate this U or are leached of 234U and U will show U-series disequilibrium. Isotope data can thus provide time-sensitive information on hydrologic conditions in host rocks without directly observing or measuring flowing water. To investigate NNSS fracture networks, core was selected from confining units (bedded and zeolitized felsic tuffs) and aquifers (felsic welded tuffs and lavas) in five boreholes on Pahute Mesa and two boreholes on Rainier Mesa. Samples include interiors of intact core as well as natural fracture surfaces and brecciated core. Intact core and brecciated samples were crushed and powdered. Fracture surfaces were sampled using dental burs to remove the outer 0.1 to 0.5 mm of fracture surfaces, which may have thin mineral coatings of zeolites, clays, and Mn oxides. Samples were totally digested, spiked with a 236U-229Th tracer, and analyzed by a solid-source TRITON° mass spectrometer equipped with an energy filter and single ion counter. Results show that 8 of 9 intact core samples have 234U/238U AR within ±5% of 1.0, suggesting little or no water-rock interaction over the last several hundred thousand years. In contrast, discrete fracture surfaces (N=37) have 234U/238U AR ranging from 2.09 to 0.34, although the median value is 1.04. About one third of the 28 SZ fracture surfaces have 234U/238U AR within 5% of 1.0. Remaining SZ fractures tend to have 234U/238U > 1.0,indicating that U incorporation from migrating groundwater (234U/238U AR ? 2-4) is an important process. Furthermore, samples with isotopic disequilibrium commonly plot along the equiline (equal 234U/238U and 230Th/238U AR) regardless of sample type or location. This pattern cannot be explained by deposition and closed-system isotope evolution of secondary minerals. Instead, it suggests a quasi-steady-state balance of processes including sorption or leaching of U associated with migrating solutions and in-situ production, decay, and ?-recoil of 230Th and 234U. These data will be used to help constrain numerical models of fracture-matrix interaction and spatial distribution of flowing versus non-flowing fractures.

  11. Comment on Ra-Th disequilibria systematics: Timescale of carbonatite magma formation at Oldoinyo Lengai volcano, Tanzania

    SciTech Connect

    Gittins, J. (Univ. of Toronto, Ontario (Canada))

    1988-04-01

    This paper discusses potential flaws in study by Williams, Gill, and bruland (1986) dealing with the extreme disequilibria between uranium and thorium series nuclides in alkalic carbonatite lava specimens. It discusses the apparent discrepencies between chemical compositions of lava which were reported from the same eruption. Clarification is made on the actual timing of eruptions in this volcanic region and the effects this would have on the petrogenesis interpretation of these rocks.

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

    USGS Publications Warehouse

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

    1991-01-01

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

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

    SciTech Connect

    Bischoff, J.L.; Fitzpatrick, J.A. (Geological Survey, Menlo Park, CA (USA))

    1991-02-01

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

  14. Radioactive Waste Radioactive Waste

    E-print Network

    Slatton, Clint

    #12;Radioactive Waste at UF Bldg 831 392-8400 #12;Radioactive Waste · Program is designed to;Radioactive Waste · Program requires · Generator support · Proper segregation · Packaging · labeling #12;Radioactive Waste · What is radioactive waste? · Anything that · Contains · or is contaminated

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

    SciTech Connect

    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

    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.

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

    USGS Publications Warehouse

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

    2004-01-01

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

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

    USGS Publications Warehouse

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

    2004-01-01

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

  18. Mantle melting in within-plate continental settings: Sr-Nd-Pb and U-series isotope constraints in alkali basalts from the Sicily Channel (Pantelleria and Linosa Islands, Southern Italy)

    NASA Astrophysics Data System (ADS)

    Avanzinelli, Riccardo; Braschi, Eleonora; Marchionni, Sara; Bindi, Luca

    2014-02-01

    The origin of the mantle sources of the Na-alkaline magmas erupted within the continental rift of the Sicily Channel and their melting behaviour are here investigated through the determination of Sr, Nd and Pb isotope ratios and U-series disequilibria on basaltic volcanic rocks from Linosa and Pantelleria. The isotope data, along with trace element ratios are used to assess the possible role of the interaction with the continental crust and/or the Sub-Continental Lithospheric Mantle (SCLM). The data show little variation in Sr and Nd isotopes and a continuous trend toward more radiogenic Pb isotope composition from Linosa to the oldest mafic activity of Pantelleria (i.e. Paleo-Pantelleria), with intermediate values measured in the youngest Pantelleria lavas (Neo-Pantelleria). Pantelleria basalts have ubiquitous 230Th-excess ranging from 7% to 20%. These data suggest the magmas are originated within the asthenospheric mantle, with little or no interaction with either the continental crust or the SCLM. The increasing FOZO-like character of the studied magmas and the variation of some key trace element ratios (e.g. Rb/La) argue for an increasing role of recycled oceanic material in the form of eclogite/pyroxenite dispersed within the mantle sources of these magmas. A completely distinct isotope composition is recorded in Neo-Pantelleria hawaiites from Khartibucale, which show significantly higher 87Sr/86Sr and lower 143Nd/144Nd, 206Pb/204Pb, (238U/232Th) and (230Th/232Th), but comparable (230Th/238U) with respect to all the other rocks studied. These rocks cannot be considered co-genetic with other Pantelleria basalts and are interpreted either as related to interaction with partial melts of the SCLM or to be originated from a mantle source enriched by recycled crustal material (EM-like). 235U-231Pa disequilibria were also measured in one Neo-Pantelleria hawaiite and one Neo-Pantelleria basalt. The coupled (230Th/238U) = 1.20 and (231Pa/235U) = 1.39 of the latter were used to perform quantitative dynamic melting models in order to constrain physical parameters of mantle melting in the Sicily Channel. The combined modelling yielded positive solutions only for high DU/DTh (? 2.5) and low melting rates (? < 1 × 10- 4 kg/m3/a). These data argue against any important role for amphibole in the genesis of these magmas and are consistent with a peridotite source possibly well mixed with recycled components. The modelled values of ? can also be converted into estimates of the upwelling rate of the mantle that are compatible with slow passive upwelling along the Sicily Channel rift.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

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

    USGS Publications Warehouse

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

    2002-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    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.

  2. Copyright 2000 by the Genetics Society of America Linkage Disequilibria and the Site Frequency Spectra in the su(s) and su(wa

    E-print Network

    Keinan, Alon

    Spectra in the su(s) and su(wa ) Regions of the Drosophila melanogaster X Chromosome Charles H. LangleyCopyright © 2000 by the Genetics Society of America Linkage Disequilibria and the Site Frequency decade, surveys of DNA sequence variation in natural populations of several Drosophila species and other

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

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

    SciTech Connect

    Paces, J.B.; Menges, C.M.; Bush, C.A.; Futa, K.; Millard, H.T.; Maat, P.B.; Whitney, J.W. [Geological Survey, Denver, CO (United States); Widmann, B. [Science Applications International Corp., Golden, CO (United States); Wesling, J.R. [Geomatrix Consultants, Inc., San Francisco, CA (United States)

    1994-12-31

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

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

    USGS Publications Warehouse

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

    1991-01-01

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

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

    SciTech Connect

    Schaefer, S.J.; Williams, S.N. (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

    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.

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

    USGS Publications Warehouse

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

    2013-01-01

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

  8. The raised coral reef complex of the Kenyan coast: Tridacna gigas U-series dates and geological implications

    NASA Astrophysics Data System (ADS)

    Accordi, Giovanni; Brilli, Mauro; Carbone, Federico; Voltaggio, Mario

    2010-08-01

    The Kenyan coast is characterized by a raised fossil reef complex cut by a series of morphological terraces. Shallow subtidal coralgal facies containing Tridacna gigas shells are found at different heights along the coast. Alpha-spectrometric U-series methods were applied to 18 T. gigas samples from different locations along this reef complex with an elevation range from 0 to 15 m above present sea level to obtain chronological information. Apparent U-Th ages, based on the assumption of closed system behaviour, correspond to early marine isotope stage (MIS) 5 ( n = 17) and MIS 7 ( n = 1). However, initial 234U/ 238U activity ratios exhibit a wide range, in many cases much greater than present seawater, which is likely to be associated with diagenetic alteration and migration of U-series isotopes. For this reason, we attempted a form of open system isochron dating after separating the Tridacna samples into three different groups on the basis of current elevation and distribution along the coast. An 'isochron' age of 120 ± 4 ka (1 ?) was obtained for the higher elevation group, placed in the terraced central coastal area; another age, statistically undistinguishable from the previous one, of 118 ± 7 ka (1 ?) was obtained for the group confined along the northern coast. These two groups correspond to a transgressive-regressive cycle connected to the maximum sea level highstand during the MIS 5e. A third 'isochron' age of 100 ± 4 ka (1 ?) was obtained for the group confined along the southern coast, encompassing part of the isotopic substages MIS 5c and d. Based on these data, and on the ecology of T. gigas whose optimal present-day depth range can be considered of 3-10 m below sea level, a maximum tectonic coastal uplift rate of between, respectively, 0.12 and 0.18 mm a -1 was calculated for the period since formation of these shells, and then the paleobathymetry of Tridacna facies has been inferred.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  10. High-precision U-series dating of corals from Western Australia and implications for the timing and duration of the Last Interglacial

    Microsoft Academic Search

    C. H. Stirling; T. M. Esat; M. T. McCulloch; K. Lambeck

    1995-01-01

    U-series ages using methods of thermal ionisation mass spectrometry (TIMS) are reported for Last Interglacial fossil reefs along the stable coastal margin of Western Australia. Thorium isotope ratios were measured with superior precision using methods of charge collection. High levels of precision in the measurement of both uranium and thorium isotopes has reduced the age uncertainty due to analytical errors,

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

    NASA Astrophysics Data System (ADS)

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

    2001-12-01

    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.

  12. Artificial Radioactivity

    NASA Astrophysics Data System (ADS)

    Moon, P. B.

    2014-06-01

    1. Introduction; 2. Identification and measurement of radiations and particles; 3. Radioactive processes in which Z changes by ±1; 4. Radioactive processes in which Z does not change; Index of subjects.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  14. Differential incision of the Grand Canyon related to Quaternary faulting---Constraints from U-series and Ar\\/Ar dating

    Microsoft Academic Search

    Joel Pederson; Karl Karlstrom; Warren Sharp; William McIntosh

    2002-01-01

    Incision of the Colorado River in the Grand Canyon, widely thought to have happened between ca. 6 and 1.2 Ma, has continued at variable rates along the canyon over the past ˜500 k.y., based on measurements of bedrock incision combined with U-series and 40Ar\\/39Ar ages. River incision rates downstream of the Toroweap fault in the western Grand Canyon are about

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

    Microsoft Academic Search

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

    2010-01-01

    We present the results of a combined U-series isotope and numerical modeling study of the 1912 Katmai-Novarupta eruption in Alaska. A stratigraphically constrained set of samples have compositions that range from basalt through basaltic andesite, andesite, dacite, and rhyolite. The major and trace element range can be modeled by 80–90% closed-system crystal fractionation over a temperature interval from 1279°C to

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  19. Measurement of radioactivity levels and assessment of radioactivity hazards of soil samples in Karaman, Turkey.

    PubMed

    Agar, O; Boztosun, I; Korkmaz, M E; Özmen, S F

    2014-12-01

    In this study, the levels of the natural and artificial radioactivity in soil samples collected from surrounding of Karaman in Turkey were measured. Activity concentrations of the concerned radionuclides were determined by gamma-ray spectrometry using a high-purity germanium detector with a relative efficiency of 40 % at 1.332 MeV. The results obtained for the (238)U series ((226)Ra, (214)Pb and (214)Bi), (232)Th series ((228)Ac), (40)K and fission product (137)Cs are discussed. To evaluate the radiological hazard of radioactivity in samples, the radium equivalent activity (Raeq), the absorbed dose rate (D), the annual effective dose and the external (Hex) and internal hazard index (Hin) were calculated and presented in comparison with the data collected from different areas in the world and Turkey. PMID:24587487

  20. Properties of Natural Radiation and Radioactivity

    SciTech Connect

    Strom, Daniel J.

    2009-07-13

    Ubiquitous natural sources of radiation and radioactive material (naturally occurring radioactive material, NORM) have exposed humans throughout history. To these natural sources have been added technologically-enhanced naturally occurring radioactive material (TENORM) sources and human-made (anthropogenic) sources. This chapter describes the ubiquitous radiation sources that we call background, including primordial radionuclides such as 40K, 87Rb, the 232Th series, the 238U series, and the 235U series; cosmogenic radionuclides such as 3H and 14C; anthropogenic radionuclides such as 3H, 14C, 137Cs, 90Sr, and 129I; radiation from space; and radiation from technologically-enhanced concentrations of natural radionuclides, particularly the short-lived decay products of 222Rn ("radon") and 220Rn ("thoron") in indoor air. These sources produce radiation doses to people principally via external irradiation or internal irradiation following intakes by inhalation or ingestion. The effective doses from each are given, with a total of 3.11 mSv y-1 (311 mrem y-1) to the average US resident. Over 2.5 million US residents receive over 20 mSv y-1 (2 rem y-1), primarily due to indoor radon. Exposure to radiation from NORM and TENORM produces the largest fraction of ubiquitous background exposure to US residents, on the order of 2.78 mSv (278 mrem) or about 89%. This is roughly 45% of the average annual effective dose to a US resident of 6.2 mSv y-1 (620 mrem y-1) that includes medical (48%), consumer products and air travel (2%), and occupational and industrial (0.1%). Much of this chapter is based on National Council on Radiation Protection and Measurements (NCRP) Report No. 160, "Ionizing Radiation Exposure of the Population of the United States," for which the author chaired the subcommittee that wrote Chapter 3 on "Ubiquitous Background Radiation."

  1. Mantle Heterogeneity and Melting Along a Regional Axial Depth Gradient: Th-U Disequilibria Along the Southeast Indian Ridge

    NASA Astrophysics Data System (ADS)

    Russo, C. J.; Rubin, K. H.; Graham, D. W.

    2004-12-01

    Lateral variation in mantle temperature is generally considered to be the main cause for observed global correlations between regionally averaged mid-ocean ridge basalt (MORB) chemistry and ridge axis depth (Klein and Langmuir, 1987). Axial depth should be shallower above hotter mantle because the underlying mantle crosses its solidus at greater depth compared to cooler regions, and leads to greater crustal production. One expectation of this global model is that melting beneath ridges should involve progressively more (deep) garnet peridotite as ridge depth shallows. A negative correlation between (230Th/238U) and axial depth in a global dataset (largely dominated by eastern Pacific and Atlantic MORB) generally supports this notion, because garnet is known to fractionate Th from U during melting (Bourdon et al., 1996). The extent to which such global variations reflect only variations in melting conditions of passively upwelling mantle versus other conditions related to mantle heterogeneity or actively fed melting anomalies is presently unknown. To further address this question on the regional scale, we have measured Th-U isotopes on 11 basaltic glasses collected along the Southeast Indian Ridge (SEIR) from ˜90° E to ˜117° E. This ˜2600 km section of ridge is characterized by a west to east gradient in axial depth from ˜2300 m to >4500 m, similar to that of the global ridge system away from the influence of hotspots. However, unlike the global (230Th/238U)-axial depth correlation which uses regionally averaged data for ridge segments from a range of spreading rates, the SEIR is spreading at a nearly constant rate of 70-75 mm/yr and is devoid of large transform offsets. These first 11 SEIR glasses were selected to span the geographic range and to be representative of the elemental and isotopic compositions. Th and U concentrations range from 130-940 ppb and 55-267 ppb, respectively, with Th/U values ranging from 2.36 to 3.77. All samples show 230Th excesses, with (230Th/238U) ranging from 1.01 to 1.24. There is no correlation between (230Th/238U) and axial depth, in contrast to the simple prediction from the global scale model. On a (238U/232Th)-(230Th/232Th) equiline diagram the SEIR data form 3 geographical, non-collinear groupings: three basalts from the westernmost portion of our study area have the highest (230Th/232Th) and (238U/232Th), the easternmost basalt has significantly lower values, and basalts from a central region (101° E to 114° E) have intermediate values. The 7 central region basalts form a well-correlated positively sloping (230Th/232Th) vs. (238U/232Th) array which is shallower than the equiline and extends from 7% to 24% 230Th-excess. Overall, (230Th/232Th) shows a strong negative correlation with axial depth and, along with Th/U, correlates well with other isotopic tracers such as 3He/4He and 208Pb/206Pb, which vary systematically along axis. In contrast, (230Th/238U) shows no systematic variations with these isotopic parameters or axial depth. Unlike the global dataset, the Th-U disequilibria in SEIR MORB suggests that, at a regional scale, melting in the Indian Ocean mantle is primarily controlled by variations in mantle composition.

  2. Radioactive fallout and radioactive strontium

    Microsoft Academic Search

    W. F. Libby

    1956-01-01

    The contribution to environmental radioactivity of radioactivity due to fallout following the explosion of nuclear weapons is reviewed. Mechanisms by which ⁹°Sr might be expected to enter the human body are discussed in detail. Data from nuclear weapons tests form the basis for the conclusion that the main part of the radioactivity from high-yield weapons dissipates in the stratosphere, but

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

  4. Mass spectrometric U-series dating of Huanglong Cave in Hubei Province, Central China: evidence for early presence of modern humans in Eastern Asia.

    PubMed

    Shen, Guanjun; Wu, Xianzhu; Wang, Qian; Tu, Hua; Feng, Yue-xing; Zhao, Jian-xin

    2013-08-01

    Most researchers believe that anatomically modern humans (AMH) first appeared in Africa 160-190 ka ago, and would not have reached eastern Asia until ?50 ka ago. However, the credibility of these scenarios might have been compromised by a largely inaccurate and compressed chronological framework previously established for hominin fossils found in China. Recently there has been a growing body of evidence indicating the possible presence of AMH in eastern Asia ca. 100 ka ago or even earlier. Here we report high-precision mass spectrometric U-series dating of intercalated flowstone samples from Huanglong Cave, a recently discovered Late Pleistocene hominin site in northern Hubei Province, central China. Systematic excavations there have led to the in situ discovery of seven hominin teeth and dozens of stone and bone artifacts. The U-series dates on localized thin flowstone formations bracket the hominin specimens between 81 and 101 ka, currently the most narrow time span for all AMH beyond 45 ka in China, if the assignment of the hominin teeth to modern Homo sapiens holds. Alternatively this study provides further evidence for the early presence of an AMH morphology in China, through either independent evolution of local archaic populations or their assimilation with incoming AMH. Along with recent dating results for hominin samples from Homo erectus to AMH, a new extended and continuous timeline for Chinese hominin fossils is taking shape, which warrants a reconstruction of human evolution, especially the origins of modern humans in eastern Asia. PMID:23870460

  5. Radioactivity Environmental Protection Course

    E-print Network

    Ishii, Hitoshi

    D1 D4 D5 D1 Radioactivity Environmental Protection Course Radioactivity Environmental Protection Course Radioactivity Social Recovery Course protect the environment from radioactivity protect human lives from radiation disasters protect the human society from radioactivity Development of Phoenix

  6. Radioactive Iodine

    MedlinePLUS

    ... muscles, and other organs working normally. Why is iodine used in some thyroid gland treatment? Iodine is ... it is concentrated as iodide. What is radioactive iodine (rai)? Iodine, in the form of iodide, is ...

  7. Radioactivity Calculations

    ERIC Educational Resources Information Center

    Onega, Ronald J.

    1969-01-01

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

  8. Simulated Radioactivity

    ERIC Educational Resources Information Center

    Boettler, James L.

    1972-01-01

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

  9. Concentrating Radioactivity

    ERIC Educational Resources Information Center

    Herrmann, Richard A.

    1974-01-01

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

  10. Constraints on crystal storage timescales in mixed magmas: Uranium-series disequilibria in plagioclase from Holocene magmas at Mount Hood, Oregon

    NASA Astrophysics Data System (ADS)

    Eppich, Gary R.; Cooper, Kari M.; Kent, Adam J. R.; Koleszar, Alison

    2012-02-01

    Uranium-series crystal ages, interpreted within a textural and geochemical framework, can provide insight into crystal storage timescales, especially in cases where crystals may derive from multiple sources. We report here 230Th-226Ra model ages of two distinct populations of plagioclase from low silica dacites from Mount Hood, Oregon, a volcano where previous studies show that the compositions of erupted magmas are controlled by magma recharge, mixing, and incorporation of plagioclase derived from mafic and silicic end-member magmas. We have measured trace element concentrations and 238U-230Th-226Ra disequilibria in four plagioclase size fractions from the Timberline (1500 a) and Old Maid (215 a) eruptive sequences. After correction for groundmass and apatite contamination, average 230Th-226Ra model ages of large (> 500 ?m) plagioclase are > 4.5 ka (Timberline) and > 5.5 ka (Old Maid), with ages of cores that are > 10 ka in each case, indicating that plagioclase derived from silicic magmas crystallized thousands of years before eruptions. These model ages are longer than timescales of repose between eruptions, indicating that these crystals resided in the sub-surface over multiple eruptions, likely stored in a silicic crystal mush zone that periodically interacts with mafic recharge magmas, remobilizing a fraction of the large plagioclase crystals during each eruptive event. After correction for large plagioclase contamination, small (< 500 ?m) plagioclase, derived from mafic magmas, have high (226Ra)/Ba relative to equilibrium with liquid proxies (groundmass and mafic inclusion), leading to 230Th-226Ra model ages that are <~3 ka for Old Maid and undefined for Timberline separates. However, the preservation of significant 230Th-226Ra disequilibria require that the majority of crystals in the separate are young (<<10 ka). The high (226Ra)/[Ba] could potentially be explained by rapid crystallization immediately prior to and/or during mixing events, consistent with evidence of rapid crystallization of rims. Rapid crystallization of mafic intrusions may trigger eruption at Mount Hood by producing a partially-crystalline mafic magma capable of mixing with a reheated silicic crystal mush.

  11. Radioactive Wastes

    NSDL National Science Digital Library

    Smith, David

    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.

  12. Radioactive Wastes

    NSDL National Science Digital Library

    David Smith

    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.

  13. Radioactive Waste.

    ERIC Educational Resources Information Center

    Blaylock, B. G.

    1978-01-01

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

  14. Radioactive Decay

    NSDL National Science Digital Library

    Barker, William

    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.

  15. Radioactive Transitions

    NSDL National Science Digital Library

    This resource provides an interactive activity demonstrating how radioactive transitions (photon absorption and stimulated emission) occur in an optical field. Many important phenomena are emergent behaviors of this dynamic model. An interactive diagram is presented allowing students to experiment and watch a simulation of the result.

  16. Radioactive fallout

    Microsoft Academic Search

    Libby

    1955-01-01

    Radioactive fallout from the Nevada tests does not provide a great danger to any inhabitants of the US or to the world in general, for the AEC has not been indiscrete in its testing of nuclear weapons. The data presented to the public in this discussion provides the first reliable and realistic estimate of the hazards associated with nuclear warfare.

  17. Sealed Radioactive Sources

    MedlinePLUS

    ... in which the metal can become contaminated with radioactivity, EPA determined that lost, abandoned, or stolen radioactive ... and Health Administration (OSHA) OSHA regulates exposure to radioactivity in the workplace. Radioactive Source Recovery Efforts This ...

  18. U-series disequilibrium in rear-arc volcanoes from the Northern Volcanic Zone in Ecuador; along-arc variation and implications for petrogenetic processes

    NASA Astrophysics Data System (ADS)

    Garrison, J. M.; Matthews, T. P.; Sims, K. W.; Escobar, R. D.; Yogodzinski, G. M.; Waters, C. L.

    2012-12-01

    Ecuador has been the focus of several studies that document the across-arc geochemical variation in the Northern Volcanic Zone (NVZ), and these studies have been useful in illustrating that from west to east, the lavas are higher in alkali and the fluid mobile elements. Of less focus has been the north to south along-arc variation that is illustrated by volcanoes including Sumaco, Pan de Azucar and El Reventador. Reventador is the northernmost volcano in the rear-arc of the NVZ and has been active since a renewed cycle of activity began in November 2002. Sumaco is located 30 km to the south and has been inactive since at least 1933, although no historic eruptions have been recorded for this volcano. Located between these two volcanoes is the inactive Pan de Azucar volcano, for which there exists no data on the eruptive history. The goal of this research is to document changes in geochemical variation from north to south in the rear-arc of Ecuador and to link this to a petrogenetic process or processes. During a 2010 expedition we collected samples from Sumaco and Reventador Volcanoes, and obtained samples from Pan de Azucar volcano from our colleagues at the IGEPN in Quito. Samples were analyzed for U-series isotopes in addition to major and trace elements. In terms of major and trace elements, El Reventador lavas are weakly alkaline and contain plagioclase, pyroxene and olivine as the major phases, whereas the Sumaco lavas are strongly alkaline and contain titanian augite and hauyne as major phases. The Pan de Azucar samples are compositionally intermediate between the two. Generally speaking, from north to south Ba/Nb decreases from a maximum of 150 at Reventador to 50 at Sumaco, whereas the La/Yb increases from 30 to 50. Other systematic N-S changes include decreasing Ba/Th, which is negatively correlated with Sr concentrations that range from 1000 (Reventador) to 4000 (Sumaco). This is consistent with lower fluid input from N-S that generates smaller degrees of melting. The U-series data give conflicting results, the highest (238U/230Th) values are at Sumaco, and range from 0.87 to 1.7. The majority of samples have 238U excesses of up to 70% with the exception of the most evolved samples, which have 230Th excesses of 15%. The Reventador samples, on the other hand have much lower 238U excesses of up to only 10% and (238U/230Th) values that range from 0.87 - 1.1. Higher 238U excesses are typically thought to reflect higher fluid input, however the trace element data are consistent with higher fluid input at Reventador, not Sumaco. One possible explanation for this is that the 238U excesses at Sumaco are primarily due to differentiation of minerals that sequester Th, perhaps apatite. The (238U/230Th) of the Sumaco lavas is highly correlated differentiation indexes like La/Yb, MgO and P2O5, whereas the Reventador samples show a much weaker correlation. We conclude that there is a systematic trend showing decreasing H2O input from north to south in the rear arc of the NVZ, and that the U-series data reveal differences in differentiation processes.

  19. Radioactive Wastes

    NSDL National Science Digital Library

    Moore, Lang

    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.

  20. 238U-230Th-226Ra disequilibria in plagioclase from recent mixed magmas at Mount Hood: constraints on crystal storage timescales and eruption triggering processes

    NASA Astrophysics Data System (ADS)

    Eppich, G. R.; Cooper, K. M.; Kent, A. J.; Koleszar, A. M.

    2010-12-01

    Uranium-series crystal ages, interpreted within a textural and geochemical framework, can provide insight into crystal storage timescales and eruption triggering processes. Mount Hood is a mixing-driven volcano that consistently erupts magmas of intermediate composition. Mixed magmas incorporate plagioclase derived from mafic and silicic end-member magmas (Kent AJR; Darr C; Koleszar AM; Salisbury MJ; Cooper KM. 2010. Preferential eruption of andesitic magmas through recharge filtering. Nature Geosci.). We measured 238U-230Th-226Ra disequilibria for four plagioclase size fractions, groundmass separates, and mafic inclusions from the Timberline (1500 a) and Old Maid (215 a) eruptive sequences. Measured (230Th)/(238U) was 1.126-1.143 for Timberline plagioclase and 1.127-1.143 for Old Maid plagioclase. Measured (226Ra)/(230Th) was 1.22-1.62 for Timberline plagioclase and 1.27-1.43 for Old Maid plagioclase. Corrections were performed for the presence of groundmass in the >500 µm plagioclase separates, and large plagioclase + groundmass in the <500 µm plagioclase separates. Small (<500 µm) plagioclase, derived from mafic magma, records enriched present-day (226Ra)/Ba relative to equilibrium with liquid proxies (groundmass and mafic inclusions), leading to undefined Ra-Th model ages. However, the measured disequilibria require that the majority of plagioclase in the separate is young (<<10 ka). Large (>500 µm) plagioclase, derived from the silicic mixing end-member, records (238U)/(230Th) disequilibrium and minor (226Ra)/(230Th) disequilibrium. Ra-Th model ages are 5-10 ka. Rims of large plagioclase crystallized within weeks of eruption (Kent et al., 2010), suggesting that the 5-10 ka Ra-Th model ages are averages of young rim growth and old cores, which could be >10 ka. Crystallization timescales of large plagioclase cores are longer than timescales of repose between eruptions, suggesting that the crystals must have been present yet remained untapped during older eruptive sequences. Extended crystal storage timescales can be best explained by storage in a silicic crystal mush, which is periodically tapped by intruding mafic recharge magmas. Only a fraction of large plagioclase crystals are remobilized by each recharge magma. In contrast, the undefined ages of small plagioclase are consistent with rapid crystallization, perhaps within weeks of eruption (similar to large plagioclase rims), resulting in higher Ra/Ba than predicted by partition coefficients. This interpretation is consistent with euhedral, acicular crystal textures and lack of complex zoning observed in small plagioclase. Rapid crystallization may trigger eruption at Mount Hood by concentrating volatiles in the liquid phase. Exsolved volatiles may increase the efficiency of mixing between mafic and silicic magmas, and can explain how two magmas with greatly differently rheological properties mix in the Mount Hood sub-surface.

  1. Cluster Radioactivity

    NASA Astrophysics Data System (ADS)

    Poenaru, Dorin N.; Greiner, Walter

    One of the rare examples of phenomena predicted before experimental discovery, offers the opportunity to introduce fission theory based on the asymmetric two center shell model. The valleys within the potential energy surfaces are due to the shell effects and are clearly showing why cluster radioactivity was mostly detected in parent nuclei leading to a doubly magic lead daughter. Saddle point shapes can be determined by solving an integro-differential equation. Nuclear dynamics allows us to calculate the half-lives. The following cluster decay modes (or heavy particle radioactivities) have been experimentally confirmed: 14C, 20O, 23F, 22,24-26Ne, 28,30Mg, 32,34Si with half-lives in good agreement with predicted values within our analytical superasymmetric fission model. The preformation probability is calculated as the internal barrier penetrability. An universal curve is described and used as an alternative for the estimation of the half-lives. The macroscopic-microscopic method was extended to investigate two-alpha accompanied fission and true ternary fission. The methods developed in nuclear physics are also adapted to study the stability of deposited atomic clusters on the planar surfaces.

  2. RADIOACTIVE LUMINOUS PAINTS

    Microsoft Academic Search

    Wahl

    1961-01-01

    The first 2 parts of this series discuss in a very popular but ; instructive manner the scientific foundations of radioactive luminescence, ; including the history of radioactivity, the structure of the atom, radioactive ; decay and alpha , beta , gamma radiation, natural and artifical ; radioisotopes, light production through radioactivity, and processes involved in ; radioactive luminescence. In

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

    USGS Publications Warehouse

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

    2010-01-01

    We present the results of a combined U-series isotope and numerical modeling study of the 1912 Katmai-Novarupta eruption in Alaska. A stratigraphically constrained set of samples have compositions that range from basalt through basaltic andesite, andesite, dacite, and rhyolite. The major and trace element range can be modeled by 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.

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

    PubMed

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

    2014-10-01

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

  5. Rates of late Quaternary normal faulting in central Tibet from U-series dating of pedogenic carbonate in displaced fluvial gravel deposits

    NASA Astrophysics Data System (ADS)

    Blisniuk, Peter M.; Sharp, Warren D.

    2003-10-01

    Along the main boundary fault of the central Tibetan Shuang Hu graben, two well-preserved fluvial terrace surfaces are vertically offset by ˜1.3 m (terrace I) and ˜14.8 m (terrace II). Using thermal ionization mass spectrometry (TIMS), we have determined 48 230Th- 234U- 238U ages of small (10-40 mg) samples from pedogenic carbonate rinds on clasts in the terrace deposits. Based on textural, microstratigraphic and geochemical criteria, we conclude that the U-series ages of innermost-rind samples provide reliable ages of 16.4±1.9 ka for terrace I, and 233.1±9.3 ka for terrace II. This constrains the average rate of vertical displacement along the normal fault to be 0.079±0.011 mm/yr during the past ˜16 kyr, and 0.064±0.007 mm/yr during the past ˜233 kyr. Combining these results with slip-rate estimates for other normal faults along the graben margins indicates that the cumulative vertical displacement on all normal faults did not exceed ˜0.3 mm/yr during the late Quaternary. This new rate from central Tibet is distinctly lower than the rate of 1.9±0.6 mm/yr inferred for normal faults bounding the Yadong-Gulu graben system in southern Tibet, consistent with more pronounced and common graben development in southern Tibet. We therefore suggest that normal faulting in southern Tibet is largely controlled by local processes, and that the age of its initiation is not a valid proxy for uplift of the Tibetan plateau, as has been widely assumed. Our data also place chronologic constraints on the termination of periglacial conditions in central Tibet during the last three interglaciations. Rind formation appears to have been relatively continuous on clasts in terrace I from ˜16 ka. Clast rinds from terrace II, in contrast, are characterized by three main episodes of rind growth that are widely separated in time. The earliest and least well-preserved episode started at 233.1±9.3 ka, a second episode occurred at 131.8±7.8 ka, and a third episode was approximately coeval with rind formation in terrace I after 16.4±1.9 ka. In each case, the age of onset of carbonate rind accumulation coincides with independently estimated ages of global deglaciation. Accordingly, we conclude that periglacial conditions in the central Tibetan plateau terminated synchronously with early stages of global warming following the last three glacial maxima, and that fluvial aggradation, terrace formation, and pedogenic carbonate accumulation in terrace soils ensued rapidly.

  6. Oxygen isotope heterogeneity and disequilibria of olivine crystals in large volume Holocene basalts from Iceland: Evidence for magmatic digestion and erosion of Pleistocene hyaloclastites

    NASA Astrophysics Data System (ADS)

    Bindeman, Ilya; Gurenko, Andrey; Sigmarsson, Olgeir; Chaussidon, Marc

    2008-09-01

    This work considers petrogenesis of the largest Holocene basaltic fissure eruptions of Iceland, which are also the largest in the world: Laki (1783-84 AD, 15 km 3), Eldgjá (934 AD, 18 km 3), Veidivötn (900, 1480 AD, multiple eruptions, >2 km 3), Núpahraun (ca. 4000 BP, >1 km 3) and Thjórsárhraun (ca 8000 BP, >20 km 3). We present oxygen isotope laser fluorination analyses of 55 individual and bulk olivine crystals, coexisting individual and bulk plagioclase phenocrysts, and their host basaltic glasses with average precision of better than 0.1‰ (1SD). We also report O isotope analyses of cores and rims of 61 olivine crystals by SIMS with average precision on single spots of 0.24‰ (1SD) in 13 samples coupled with electron microprobe data for major and trace elements in these olivines. Within each individual sample, we have found that basaltic glass is relatively homogeneous with respect to oxygen isotopes, plagioclase phenocrysts exhibit crystal to crystal variability, while individual olivines span from the values in equilibrium with the low-? 18O matrix glass to those being three permil higher in ? 18O than the equilibrium. Olivine cores with maximum value of 5.2‰ are found in many of these basalts and suggest that the initial magma was equilibrated with normal-? 18O mantle. No olivines or their intracrystalline domains are found with bulk or spot value higher than those found in MORB olivines. The ? 18O variability of 0.3-3‰ exists for olivine grains from different lavas, and variable core-to-rim oxygen isotopic zoning is present in selected olivine grains. Many olivines in the same sample are not zoned, while a few grains are zoned with respect to oxygen isotopes and exhibit small core-to-core variations in Fe-Mg, Ni, Mn, Ca. Grains that are zoned in both Mg# and ? 18O exhibit positive correlation of these two parameters. Electron microprobe analysis shows that most olivines equilibrated with the transporting melt, and thin Fe-richer rim is present around many grains, regardless of the degree of olivine-melt oxygen isotope disequilibrium. The preservation of isotopic and compositional zoning in selected grains, and subtle to severe ? 18O (melt-olivine) and ? 18O (plagioclase-olivine) disequilibria suggests rather short crystal residence times of years to centuries. Synglacially-altered upper crustal, tufaceous hyaloclastites of Pleistocene age serve as a viable source for low-? 18O values in Holocene basalts through assimilation, mechanical and thermal erosion, and devolatilization of stoped blocks. Cumulates formed in response to cooling during assimilation, and xenocrysts derived from hyaloclastites, contribute to the diverse ? 18O crystalline cargo. The magma plumbing systems under each fissure are likely to include a network of interconnected dikes and sills with high magma flow rates that contribute to the efficacy of magmatic erosion of large quantities (10-60% mass) of hyaloclastites required by isotopic mass balance. Olivine diversity and the pervasive lack of phenocryst-melt oxygen isotopic equilibrium suggest that a common approach of analyzing bulk olivine for oxygen isotopes, as a proxy for the basaltic melt or to infer mantle ? 18O value, needs to proceed with caution. The best approach is to analyze olivine crystals individually and demonstrate their equilibrium with matrix.

  7. Variance components model with disequilibria

    Microsoft Academic Search

    Ao Yuan; Guanjie Chen; Qi Yang; Charles Rotimi; George Bonney

    2006-01-01

    The variance components (VC) model has been popular for genetic analysis. It has received wide applications in a variety of genetic practices, and been extended to various forms for different settings. However, most of the existing VC models are, explicitly or implicitly, under the assumption of the Hardy–Weinberg and\\/or linkage equilibria, which is impractical in some realistic settings since more

  8. Radioactivity in consumer products

    SciTech Connect

    Moghissi, A.A.; Paras, P.; Carter, M.W.; Barker, R.F. (eds.)

    1978-08-01

    Papers presented at the conference dealt with regulations and standards; general and biological risks; radioluminous materials; mining, agricultural, and construction materials containing radioactivity; and various products containing radioactive sources.

  9. Radioactive iodine uptake

    MedlinePLUS

    ... the testing center so that the amount of radioactivity in the thyroid gland can be measured. This ... The amount of radioactivity is very small, and there have been no documented side effects. The amount of iodine used is less than ...

  10. Procedures for radioactive I-131

    SciTech Connect

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

    1988-12-01

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

  11. Radioactive Counting Clocks

    Microsoft Academic Search

    Shankar Radhakrishnan; Amit Lal

    2006-01-01

    We report on a radioactive counting clock (RCC) based on radioactive beta emissions from nickel-63 thin films. We present a theoretical analysis of the clock that uses the radioactive source (physics package) to lock and stabilize the frequency of a voltage-to-frequency converter (local oscillator). We present frequency stability measurements of the RCC over 10 days of clock operation. We analyze

  12. Radioactive Decay 1. Background

    E-print Network

    Elster, Charlotte

    Radioactive Decay 1. Background It is well known that many nuclei are unstable and are transformed into other nuclear species by means of either alpha decay or beta decay. The rate at which those radioactive on the number N of radioactive nuclei in the sample and also on the probability for each nucleus to decay

  13. Radioactive Materials License Commitments

    E-print Network

    Radioactive Materials License Commitments for The University of Texas at Austin May 2009 July 2009 in the use of radioactive materials. In July 1963, the State of Texas granted The University of Texas at Austin a broad radioactive materials license for research, development and instruction. While this means

  14. Radioactive Waste: 1. Radioactive waste from your lab is

    E-print Network

    Jia, Songtao

    Radioactive Waste: 1. Radioactive waste from your lab is collected by the RSO. 2. Dry radioactive waste must be segregated by isotope. 3. Liquid radioactive waste must be separated by isotope. 4. Liquid disposable gloves. 4. Keep the RSO telephone # handy. 5. Label all radioactive vials. 6. Apply common sense

  15. Radioactive Waste Management Basis

    SciTech Connect

    Perkins, B K

    2009-06-03

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

  16. Radioactive Wastes. Revised.

    ERIC Educational Resources Information Center

    Fox, Charles H.

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

  17. Radioactive waste management

    Microsoft Academic Search

    N. Tsoulfanidis; R. G. Cochran

    1991-01-01

    The management of radioactive waste is a very important part of the nuclear industry. The future of the nuclear power industry depends to a large extent on the successful solution of the perceived or real problems associated with the disposal of both low-level waste (LLW) and high-level waste (HLW). All the activities surrounding the management of radioactive waste are reviewed.

  18. Radioactive waste disposal package

    DOEpatents

    Lampe, Robert F. (Bethel Park, PA)

    1986-01-01

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

  19. A Remote Radioactivity Experiment

    ERIC Educational Resources Information Center

    Jona, Kemi; Vondracek, Mark

    2013-01-01

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

  20. Temporary Personal Radioactivity

    ERIC Educational Resources Information Center

    Myers, Fred

    2012-01-01

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

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

    SciTech Connect

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

    1999-12-01

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

  2. Radioactive Iodine Treatment for Hyperthyroidism

    MedlinePLUS

    ... Radioactive Iodine for Hyperthyroidism Share: Fact Sheet Radioactive Iodine for Hyperthyroidism April, 2012 Download PDFs English Zulu ... prepare for RAI or surgery. How does radioactive iodine treatment work? Iodine is important for making thyroid ...

  3. Consumer Products Containing Radioactive Materials

    MedlinePLUS

    ... radioactive material. Many consumer items containing naturally occurring radioactivity can be safely used. This fact sheet describes ... levels of uranium and radium. The amount of radioactivity incorporated into the plants is low and does ...

  4. Understanding radioactive waste

    SciTech Connect

    Murray, R.L.

    1981-12-01

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

  5. Dynamic radioactive particle source

    DOEpatents

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

    2012-06-26

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

  6. Container for radioactive materials

    DOEpatents

    Fields, Stanley R. (Richland, WA)

    1985-01-01

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

  7. Radioactive Decay Calculator

    NSDL National Science Digital Library

    Alan Enns

    This online calculator computes radioactive decay, timed decay, and timed solid disposal for a databank containing 116 isotopes. It also features University of British Columbia disposal limits and a unit converter and date/time calculators. These tools calculate the half-life for selected isotopes; radioactive decay final activity, given the initial activity and decay time; the decay time, given the initial and final activities; and the decay time, given the mass of a solid and the initial activity.

  8. (Revised May 25, 2012) Radioactivity

    E-print Network

    Collins, Gary S.

    (Revised May 25, 2012) Radioactivity GOALS (1) To gain a better understanding of naturally and/or energy in the process. This process is called radioactive decay or, simply, radioactivity be dangerous if the radioactive material is ingested into the body. Beta particles are simply electrons. Gamma

  9. Radioactivity in food crops

    SciTech Connect

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

    1983-05-01

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

  10. 238U-230Th-226Ra disequilibria in dacite and plagioclase from the 2004-2005 eruption of Mount St. Helens: Chapter 36 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Cooper, Kari M.; Donnelly, Carrie T.

    2008-01-01

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

  11. Radioactive mixed waste disposal

    SciTech Connect

    Jasen, W.G.; Erpenbeck, E.G.

    1993-02-01

    Various types of waste have been generated during the 50-year history of the Hanford Site. Regulatory changes in the last 20 years have provided the emphasis for better management of these wastes. Interpretations of the Atomic Energy Act of 1954 (AEA), the Resource Conservation and Recovery Act of 1976 (RCRA), and the Hazardous and Solid Waste Amendments (HSWA) have led to the definition of radioactive mixed wastes (RMW). The radioactive and hazardous properties of these wastes have resulted in the initiation of special projects for the management of these wastes. Other solid wastes at the Hanford Site include low-level wastes, transuranic (TRU), and nonradioactive hazardous wastes. This paper describes a system for the treatment, storage, and disposal (TSD) of solid radioactive waste.

  12. Container for radioactive materials

    DOEpatents

    Fields, S.R.

    1984-05-30

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

  13. Environmental Radioactivity, Temperature, and Precipitation.

    ERIC Educational Resources Information Center

    Riland, Carson A.

    1996-01-01

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

  14. Vacuuming radioactive sludge

    SciTech Connect

    2006-10-16

    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.

  15. New Proton Radioactivity Measurements

    E-print Network

    Edinburgh, University of

    New Proton Radioactivity Measurements Richard J. Irvine Thesis submitted for the degree of Doctor to search for examples of proton emission from ground and low­lying states in odd­Z nuclei at the proton into a double­sided silicon strip detector system, where their subsequent particle decays (proton or alpha) were

  16. Radioactive Decay - An Analog.

    ERIC Educational Resources Information Center

    McGeachy, Frank

    1988-01-01

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

  17. TABLE OF RADIOACTIVE ELEMENTS.

    SciTech Connect

    HOLDEN,N.E.

    2001-06-29

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

  18. Viewer Makes Radioactivity "Visible"

    NASA Technical Reports Server (NTRS)

    Yin, L. I.

    1983-01-01

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

  19. Table of radioactive isotopes

    Microsoft Academic Search

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

    1986-01-01

    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

  20. Radioactivity: A Natural Phenomenon.

    ERIC Educational Resources Information Center

    Ronneau, C.

    1990-01-01

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

  1. Method for calcining radioactive wastes

    DOEpatents

    Bjorklund, William J. (Richland, WA); McElroy, Jack L. (Richland, WA); Mendel, John E. (Kennewick, WA)

    1979-01-01

    This invention relates to a method for the preparation of radioactive wastes in a low leachability form by calcining the radioactive waste on a fluidized bed of glass frit, removing the calcined waste to melter to form a homogeneous melt of the glass and the calcined waste, and then solidifying the melt to encapsulate the radioactive calcine in a glass matrix.

  2. Hazardous and radioactive substances in

    E-print Network

    Hazardous and radioactive substances in danisH Marine Waters Ingela Dahllöf & Jesper H. Andersen University #12;#12;Hazardous and radioactive substances in danisH Marine Waters #12;#12;Hazardous and radioactive substances in danisH Marine Waters Ingela Dahllöf and Jesper H. Andersen Editors Agency

  3. Radioactive Contamination of Danish Territory

    E-print Network

    » & Risø-R-462 Radioactive Contamination of Danish Territory after Core-melt Accidents 1982 Risø National Laboratory, DK-4000 Roskilde, Denmark #12;RIS�-R-462 RADIOACTIVE CONTAMINATION. Heikel Vinther, L. Warming and A. Aarkrog Abstract. An assessment is made of the radioactive

  4. Tracking Radioactive Sources in Commerce

    E-print Network

    Tracking Radioactive Sources in Commerce Deborah Kopsick, U.S. Environmental Protection Agency Schultz, Dudley Pinson; NorthWest Nuclear, LLC Millions of radioactive material packages are shipped each year © In transit, sealed radioactive sources may be vulnerable to loss or theft due to: � Minimal

  5. Radioactive Contamination of Danish Territory

    E-print Network

    Risø-R-462 Radioactive Contamination of Danish Territory after Core-melt Accidents at the Barsebäck;#12;RIS0-R-462 RADIOACTIVE CONTAMINATION OF DANISH TERRITORY AFTER CORE-MELT ACCIDENTS AT THE BARSEBACK. An assessment is made of the radioactive contamination of Danish territory in the event of a core-melt accident

  6. Environmental Radioactivity in the Faroes

    E-print Network

    I Radioactivity in the Faroes in 1979 A. Aarkrog and J. Lippeit Risø National Laboratory, DK-4000 Roskilde, Denmark July 1980 #12;Risø-R-422 ENVIRONMENTAL RADIOACTIVITY IN THE FAROES IN 1979 A. Aarkroo and J. Lippert Abstract. Measurements of fallout radioactivity in the Faroes

  7. Radioactive ion detector

    DOEpatents

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

    1997-08-12

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

  8. Radiations from Radioactive Substances

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

  9. Radioactive ion detector

    DOEpatents

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

    1997-01-01

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

  10. Table of radioactive elements

    SciTech Connect

    Holden, N.E.

    1985-01-01

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

  11. (Immobilization of radioactive wastes)

    Microsoft Academic Search

    Dole

    1986-01-01

    The traveler participated as the co-chairman of the France\\/US Workshop in Cadarache, France, on the immobilization of radioactive wastes in cement-based materials. These meetings and site visits were conducted under the bilateral exchange agreement between the US-DOE and the Commissariate a l'Energie Atomique (CEA-France). Visits in France included the Cadarache, Valduc, Saclay, and Fontenay-aux-Roses Nuclear Research Centers. As a result

  12. Radioactive waste storage issues

    SciTech Connect

    Kunz, D.E.

    1994-08-15

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

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

    SciTech Connect

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

    2003-02-27

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  15. PERSPECTIVE: Fireworks and radioactivity

    NASA Astrophysics Data System (ADS)

    Breitenecker, Katharina

    2009-09-01

    Katharina Breitenecker Fireworks, the one and only amongst all other pyrotechnic applications, have pleased the hearts and minds of billions of people all over the world for almost 1000 years. Even though pyrotechnics were originally developed in order to fulfil the needs of military purposes, fireworks began to form a unique part of the cultural heritage of many countries, presumably starting in ancient China during the Song Dynasty (960-1280 AD). Festivities like New Year's Eve, national holidays or activities like music festivals and parish fairs are crowned by a firework display. Fireworks have traditionally been associated with Independence Day celebrations, like 4 July in the United States, Guy Fawkes' Night (5 November) in Britain, or Bastille Day (14 July) in France. Much of Chinese culture is associated with the use of firecrackers to celebrate the New Year and other important occasions. The fascination of fireworks and firecrackers is due to the brilliant colours and booming noises, which have a universal appeal to our basic senses [1]. The basic components of any traditional civil firework is black powder, a mixture of about 75% potassium nitrate, 15% charcoal, and about 10% sulfur [2]. Without the addition of a colouring agent, the fuel would provide an almost white light. Therefore, several metal salts can be added to cause colourful luminescence upon combustion. In general barium is used to obtain a green coloured flame, strontium for red, copper for blue and sodium for yellow [2, 3]. The use of pyrotechnics has raised issues pertaining to health concerns. The health aspects are not only restricted to injuries by accidental ignition of certain devices. Moreover, several recent works identified fireworks and pyrotechnics as causing environmental pollution, which might result in a potential hazard concerning health aspects. The fundamental problem in this respect is that all chemicals used are dispersed in the environment by combustion. This includes both reaction products and unburnt constituents of a pyrotechnic mixture. One major environmental concern in pyrotechnics focuses on the emission of heavy metals. This is the topic discussed in the article by Georg Steinhauser and Andreas Musilek in this issue [4]. A possible interrelationship between respiratory effects and fireworks emissions of barium-rich aerosols was also raised last year [5]. In recent years the potential hazard of naturally occurring radioactive material has become of importance to the scientific community. Naturally occurring radionuclides can be of terrestrial or cosmological origin. Terrestrial radionuclides were present in the presolar cloud that later contracted in order to build our solar system. These radionuclides—mainly heavy metals—and their non-radioactive isotopes are nowadays fixed in the matrix of the Earth's structure. Usually, their percentage is quite small compared to their respective stable isotopes—though there are exceptions like in the case of radium. The problem with environmental pollution due to naturally occurring radioactive material begins when this material is concentrated due to mining and milling, and later further processed [6]. Environmental pollution due to radioactive material goes back as far as the Copper and Iron Ages, when the first mines were erected in order to mine ores (gold, silver, copper, iron, etc), resulting in naturally occurring radioactive material being set free with other dusts into the atmosphere. So where is the link between pyrotechnics and radioactivity? In this article presented by Georg Steinhauser and Andreas Musilek [4], the pyrotechnic ingredients barium nitrate and strontium nitrate are explored with respect to their chemical similarities to radium. The fundamental question, therefore, was whether radium can be processed together with barium and strontium. If so, the production and ignition of these pyrotechnic ingredients could cause atmospheric pollution with radium aerosols, resulting in potential negative health effects, unless an extensive purification of the ores is

  16. Radioactive waste material disposal

    DOEpatents

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

    1995-01-01

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

  17. Radioactive Decay of Candium

    NSDL National Science Digital Library

    The Science House

    2014-01-28

    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.

  18. Radioactive waste material disposal

    DOEpatents

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

    1995-10-24

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

  19. Radioactive waste processing apparatus

    DOEpatents

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

    1987-01-01

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

  20. Radioactivity in Urals

    NASA Astrophysics Data System (ADS)

    Interest in the problems due to the radioactive contamination of the environment has been frequently stimulated by rumors of an occurrence of severe contamination of lakes and rivers in areas of the Ural Mountains. Occasional evidence appearing in publications and provided by Soviet emigrants has been pieced together and seems to suggest that there is an ideal opportunity for groundwater geochemists and others to evaluate such major radioactivity in the environment. The reasons that such a study probably will not take place is that the contamination may have been caused for the most part by a nuclear explosion in a Soviet weapons plant.F. Parker, an environmental scientist at Vanderbilt University, in a study for the Department of Energy, deduced that a large explosion occurred in 1958 at a nuclear fuels reprocessing plant at Kyshtym in the Ural Mountains, according to a recent report (Science, July 8, 1983). The report refers to the original interpretations of Z. Medvedev, a Soviet geneticist, who concluded that nuclear fallout has contaminated a very extensive area around Kyshtym.

  1. RSSC RADIOACTIVE WASTE DISPOSAL 08/2011 7-1 RADIOACTIVE WASTE DISPOSAL

    E-print Network

    Slatton, Clint

    RSSC RADIOACTIVE WASTE DISPOSAL 08/2011 7-1 CHAPTER 7 RADIOACTIVE WASTE DISPOSAL PAGE I. Radioactive Waste Disposal ............................................................................................ 7-2 II. Radiation Control Technique #2 Instructions for Preparation of Radioactive Waste

  2. CHERNOBYL DATA BASE ENVIRONMENTAL RADIOACTIVITY

    E-print Network

    MAY 1990 THE NORDIC CHERNOBYL DATA BASE ENVIRONMENTAL RADIOACTIVITY MEASUREMENTS Nordic liaison CHERNOBYL DATA BASE ENVIRONMENTAL RADIOACTIVITY MEASUREMENTS Final Report of the NKA Project AKT 242 Edited the members of the working group. Graphic Systems AB, Malmo 1990 #12;111 ABSTRACT. The NORDIC CHERNOBYL DATA

  3. Internal and External Radioactive Backgrounds

    E-print Network

    Chapter 3 Internal and External Radioactive Backgrounds New physics is often discovered by pushing;Chapter 3: Internal and External Radioactive Backgrounds 104 the rate of background. High-energy neutrino to find suitable construction materials. 3.1 External Backgrounds External backgrounds are those in which

  4. Heavy fragment radioactivities

    SciTech Connect

    Price, P.B.

    1987-12-10

    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.

  5. Low Radioactivity in CANDLES

    SciTech Connect

    Kishimoto, T.; Ogawa, I.; Hazama, R.; Yoshida, S.; Umehara, S.; Matsuoka, K.; Sakai, H.; Yokoyama, D.; Mukaida, K.; Ichihara, K.; Tatewaki, Y.; Kishimoto, K.; Hirano, Y.; Yanagisawa, A.; Ajimura, S. [Department of Physics, Osaka University, Toyonaka, Osaka, 560-0043 (Japan)

    2005-09-08

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

  6. Radioactive waste processing apparatus

    DOEpatents

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

    1985-08-30

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

  7. How Does Radioactive Decay Work?

    NSDL National Science Digital Library

    Wenner, Jennifer M.

    This teacher's guide with exercises is intended to help teach the topics of radioactive decay and its use to determine age. It identifies four main concepts that students are likely to struggle with: spontaneity (randomness) of radioactive decay; the importance of isotopes; the concept of half-life; and how to choose which system of isotopes to use to determine age. The guide presents suggestions on how to make these ideas more understandable, and provides three exercises that can be used to demonstrate radioactive decay. Links to additional materials and information are embedded in the resource.

  8. Apparatus for storing radioactive materials

    SciTech Connect

    Ozaki, S.

    1981-02-17

    A method and apparatus for storing radioactive materials, in which a metal halide or a metal carbonyl compound is introduced from a cylinder to the vicinity of a solid material while a gaseous radioactive material provided from a reservoir, ionized and accelerated is being implanted into the solid material, so as to allow the elemental metal to be deposited on the surface of the solid material, thereby detaining the radioactive material in the solid material and newly providing the surface of the solid material with a metal layer for multi-layer implantation.

  9. Star formation and extinct radioactivities

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.

    1984-01-01

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

  10. Radioactive decay data tables

    SciTech Connect

    Kocher, D.C.

    1981-01-01

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

  11. Radioactive Waste Management

    NASA Astrophysics Data System (ADS)

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

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

  12. (Immobilization of radioactive wastes)

    SciTech Connect

    Dole, L.R.

    1986-12-18

    The traveler participated as the co-chairman of the France/US Workshop in Cadarache, France, on the immobilization of radioactive wastes in cement-based materials. These meetings and site visits were conducted under the bilateral exchange agreement between the US-DOE and the Commissariate a l'Energie Atomique (CEA-France). Visits in France included the Cadarache, Valduc, Saclay, and Fontenay-aux-Roses Nuclear Research Centers. As a result of these discussions, an exchange of scientists between Saclay and ORNL was proposed. The traveler continued on to the FRG to visit a hazardous waste site remedial action project in Sprendlingen and the nuclear research and production facilities at the Karlsruhe Kernforschungszentrum (KfK) and the Alkem/Nukem/Transnuklear facilities at Hanau. Visits in the FRG were under the bilateral exchange agreement between the US-DOE and the Bundes Ministerium fur Forschung und Technologie (BMFT). The FRG supplied the traveler data on studies of super-compaction volume reduction efficiencies by KfK and Nukem. Also, Transnuklear is considering contributing two of their larger Konrad-certified packages to the MDU studies at ORNL. 1 tab.

  13. Radioactive waste material melter apparatus

    DOEpatents

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

    1990-01-01

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

  14. Radioactive waste material melter apparatus

    DOEpatents

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

    1990-04-24

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

  15. Radioactivity connected with coal burning.

    PubMed

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

    1985-10-01

    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

  16. Radioactive waste disposal and geology

    Microsoft Academic Search

    K. B. Krauskopf

    1988-01-01

    This book is an excellent, well-presented treatise on the nature and types of radioactive wastes, disposal alternatives and strategies, radionuclide release and disposal models, geologic repositories, natural analogues, subsea-bed options, and low-level wastes. The authors provide national and international perspectives on radioactive waste disposal problems. They carefully dissected each issue, treating its pros and cons equally. Moreover, they is careful

  17. 4. Nuclei and Radioactivity Paradoxes and Puzzles

    E-print Network

    Browder, Tom

    4. Nuclei and Radioactivity Paradoxes and Puzzles 1. This book is radioactive. 2. You are radioactive too, unless you have been dead for a long time. 3. The United States Bureau of Alcohol, Tobacco, and Firearms tests wine, gin, whisky, and vodka for radioactivity. If the product does not have sufficient

  18. Environmental Radioactivity in the North Atlantic Region.

    E-print Network

    Environmental Radioactivity in the North Atlantic Region. The Faroe Islands and Greenland included ENVIRONMENTAL RADIOACTIVITY IN THE NORTH ATLANTIC REGION. THE FAROE ISLANDS AND GREENLAND INCLUDED. 1984 A Radioactivity, Monaco Abstract. Measurements of fallout radioactivity in the North Atlantic region including

  19. A literature Review on Radioactivity Transfer to

    E-print Network

    Ã? *ISE Rise-R-450 A literature Review on Radioactivity Transfer to Plants and Soil Ole John Nielsen ON RADIOACTIVITY TRANSFER TO PLANTS AND SOIL Ole John Nielsen Abstract. The literature on transfer of radioactivity SYMBOLS 99 #12;- 5 - 1. PREFACE The report reviews literature on radioactivity transfer to plants and soil

  20. Storage depot for radioactive material

    DOEpatents

    Szulinski, Milton J. (Richland, WA)

    1983-01-01

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

  1. Radioactive materials in recycled metals.

    PubMed

    Lubenau, J O; Yusko, J G

    1995-04-01

    In recent years, the metal recycling industry has become increasingly aware of an unwanted component in metal scrap--radioactive material. Worldwide, there have been 35 instances where radioactive sources were unintentionally smelted in the course of recycling metal scrap. In some cases contaminated metal consumer products were distributed internationally. In at least one case, serious radiation exposures of workers and the public occurred. Radioactive material appearing in metal scrap includes sources subject to licensing under the Atomic Energy Act and also naturally occurring radioactive material. U.S. mills that have smelted a radioactive source face costs resulting from decontamination, waste disposal, and lost profits that range from 7 to 23 million U.S. dollars for each event. To solve the problem, industry and the government have jointly undertaken initiatives to increase awareness of the problem within the metal recycling industry. Radiation monitoring of recycled metal scrap is being performed increasingly by mills and, to a lesser extent, by scrap processors. The monitoring does not, however, provide 100% protection. Improvements in regulatory oversight by the government could stimulate improved accounting and control of licensed sources. However, additional government effort in this area must be reconciled with competing priorities in radiation safety and budgetary constraints. The threat of radioactive material in recycled metal scrap will continue for the foreseeable future and, thus, poses regulatory policy challenges for both developed and developing nations. PMID:7883556

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

    USGS Publications Warehouse

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

    2007-01-01

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

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

    PubMed

    Evangeliou, Nikolaos; Florou, Heleny; Kritidis, Panayotis

    2012-12-01

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

  4. Radioactivity of sand, groundwater and wild plants in northeast Sinai, Egypt.

    PubMed

    Ramadan, Khaled A; Seddeek, Mostafa K; Nijim, Abdelkareem; Sharshar, Taher; Badran, Hussein M

    2011-12-01

    The radioactivity levels are poorly studied in non-coastal arid regions. For this reason, 38 locations covering an area of about 350 km(2) in northeast Sinai, Egypt, were investigated by ?-ray spectroscopy. Moderately significant correlations among (238)U, (234)Th, and (226)Ra isotopes and low significant correlations between the concentrations of (238)U-series and (232)Th in sand were obtained. No evidence of correlation was found between the concentrations of radioisotopes and pH, grain size, total organic matter content, bicarbonate or calcium carbonate concentrations of the sand samples. The mean values of soil-to-plant transfer factor were 0.15, 0.18, 1.52 and 0.74 for (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. The range of concentrations of (226)Ra,( 232)Th, and (40)K in water samples collected from five wells were<0.4-0.16,<0.4-0.13, and<0.15-1.62 Bq l(-1), respectively. The mean absorbed dose rate in outdoor air at a height of 1 m above the ground surface for the sand samples was 19.4 nGy h(-1). The Ra(eq) activities of the sands are lower than the recommended maximum value of 370 Bq kg(-1) criterion limit for building materials. PMID:22092101

  5. Storage containers for radioactive material

    DOEpatents

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

    1981-01-01

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

  6. Storage containers for radioactive material

    DOEpatents

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

    1980-07-31

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

  7. Induced radioactivity in LDEF components

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

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

    MedlinePLUS

    ... with I-131. Depending on the amount of radioactivity administered during your treatment, your endocrinologist or radiation ... it begins destroying the gland's cells. Although the radioactivity from this treatment remains in the thyroid for ...

  9. The Radioactive Beam Program at Argonne

    E-print Network

    B. B. Back

    2006-06-06

    In this talk I will present selected topics of the ongoing radioactive beam program at Argonne and discuss the capabilities of the CARIBU radioactive ion production facility as well as plans for construction of a novel superconducting solenoid spectrometer.

  10. Undiagnosed Illnesses and Radioactive Warfare

    Microsoft Academic Search

    Asaf Durakoviæ

    The internal contamination with depleted uranium (DU) isotopes was detected in British, Canadian, and United States Gulf War veterans as late as nine years after inhalational exposure to radioactive dust in the Persian Gulf War I. DU iso- topes were also identified in a Canadian veteran's autopsy samples of lung, liver, kidney, and bone. In soil samples from Kosovo, hundreds

  11. OBSERVATION OF RADIOACTIVE AIRBORNE DUSTS

    Microsoft Academic Search

    T. Mamuro; A. Fujita; T. Matsunami; K. Yoshikawa; T. Azuma

    1961-01-01

    Radioactivity measurements on air-borne dusts are reported for the ; period after the beginning of the Russian nuclear explosions in Sept. 1961. The ; debris from nuclear explosions was detected by counting the samples 4 and 10 days ; after sampling. Debris was first detected in Osaka on Sept. 12, and two ; abnormal activity increases were observed on Oct.

  12. Radioactivity in bottled mineral waters

    Microsoft Academic Search

    A Mart??n Sánchez; M. P Rubio Montero; V Gómez Escobar; M Jurado Vargas

    1999-01-01

    Consumption of bottled mineral water is a growing practice and is sometimes a necessity rather than a choice. In this work, a study of the radioactive content of a wide selection of commercial bottled mineral waters for human intake was carried out. The origins of the analyzed waters were very different, coming from various locations in France, Portugal and Spain.

  13. High-Level Radioactive Waste.

    ERIC Educational Resources Information Center

    Hayden, Howard C.

    1995-01-01

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

  14. Nuclear structure from radioactive decay

    NASA Astrophysics Data System (ADS)

    Wood, J. L.

    1990-09-01

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

  15. Radioactivity and the Biology Teacher

    ERIC Educational Resources Information Center

    Hornsey, D. J.

    1974-01-01

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

  16. Method for treating radioactive liquids

    SciTech Connect

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

    1980-11-25

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

  17. Radioactive Waste Management in Korea

    Microsoft Academic Search

    Myung Jae Song

    2004-01-01

    Nuclear Environment Technology Institute (NETEC) of Korea Hydro and Nuclear Power Company, Ltd. (KHNP) is responsible for the management of radioactive waste generated from nuclear power plants and radioisotope (RI) users in Korea. KHNP\\/NETEC is also in charge of establishing efficient spent fuel storage for nuclear power plants. Among the research and development activities of KHNP\\/NETEC to develop advanced technologies

  18. Radioactive Waste Management in Perspective

    Microsoft Academic Search

    Martin A Broderick

    1996-01-01

    This report is clearly written and concise. The report will be of considerable assistance to decision-makers, opinion formers and interested members of the general public. It will form a useful summary for a non-specialist reader who is interested in radioactive waste management practices in the OECD area, and in the current expert consensus on the subject. The explanations of the

  19. Radioactive waste management and disposal

    Microsoft Academic Search

    R. Simon; S. Orlowski

    1980-01-01

    The first European Community conference on Radioactive Waste Management and Disposal was held in Luxembourg, where twenty-five papers were presented by scientists involved in European Community contract studies and by members of the Commission's scientific staff. The following topics were covered: treatment and conditioning technology of solid intermediate level wastes, alpha-contaminated combustible wastes, gaseous wastes, hulls and dissolver residues and

  20. RadioActive101 Practices

    ERIC Educational Resources Information Center

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

    2014-01-01

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

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

    PubMed

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

    2006-09-01

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

  2. Radioactive Material Declaration Form Exhibit to the Radioactive Waste Manual (RWM)

    E-print Network

    Wechsler, Risa H.

    Radioactive Material Declaration Form Exhibit to the Radioactive Waste Manual (RWM) 12/5/2013 (form date) SLAC-I-760-2A08Z-001 (RWM number) Page 1 of 2 RADIOACTIVE MATERIAL DECLARATION FORM For RP use [ ] Radioactive [ ] Toxic [ ] Friable [ ] Non-Friable [ ] None PCB Content: [ ] > 5 ppm [

  3. Calibrator for radioactivity well logging tools

    Microsoft Academic Search

    Waggoner

    1978-01-01

    A radioactivity well logging tool including a gamma radiation detector is field calibrated with the help of a flexible sheet with a radioactive substance dispersed therein, is wrapped about the tool so as to completely surround the detector. The sheet is made of an elastomer such as polyurethane, and the radioactive substance is carnotite. This sheet is placed within a

  4. RADIOACTIVE WASTE MANAGEMENT POLICY IN ROMANIA

    Microsoft Academic Search

    V. Andrei; F. Glodeanu; D. Popescu; I. Rotaru

    2000-01-01

    Radioactive waste management is a key issue of the environmental policy of our company. According to the Romanian Nuclear Act (Law 111\\/1996) and the Law of the Environmental Protection (Law 137\\/1996) the owner is responsible for the management of all radioactive wastes streams at the Nuclear Power Plant, including the technical and cost components. For radioactive waste disposal and plant

  5. Radioactivity in Food and the Environment, 2009

    E-print Network

    RIFE 15 Radioactivity in Food and the Environment, 2009 Northern Ireland Environment Agencywww ENVIRONMENT PROTECTION AGENCY Radioactivity in Food and the Environment, 2009 RIFE ­ 15 October 2010 #12, the Radioactive Substances Unit of SEPA (radiologicalmonitoring@sepa.org.uk) and · in Northern Ireland

  6. Radioactivity in Food and the Environment, 2002

    E-print Network

    Radioactivity in Food and the Environment, 2002 RIFE - 8 2003 #12;1 ENVIRONMENT AGENCY ENVIRONMENT AND HERITAGE SERVICE FOOD STANDARDS AGENCY SCOTTISH ENVIRONMENT PROTECTION AGENCY Radioactivity in Food.surveillance@foodstandards.gsi.gov.uk) · In Scotland, the Radioactive Substances Unit of SEPA (radiologicalmonitoring@sepa.org.uk) and · In Northern

  7. Radioactivity in Food and the Environment, 1997

    E-print Network

    Radioactivity in Food and the Environment, 1997 RIFE - 3 1998 SCOTTISH ENVIRONMENT PROTECTION SCOTTISH ENVIRONMENT PROTECTION AGENCY Radioactivity in Food and the Environment, 1997 September 1998 #12;2 Preface This report presents the results of surveillance programmes for radioactivity carried out

  8. Radioactivity in Food and the Environment, 1996

    E-print Network

    Radioactivity in Food and the Environment, 1996 Ministry of Agriculture, Fisheries and Food RIFE SCOTTISH ENVIRONMENTPROTECTIONAGENCY Radioactivity in Food and the Environment, 1996 September 1997 #12;2 This is the second surveillance report in the series Radioactivity in Food and the Environment. It is published

  9. Environmental Radioactivity in Denmark in 1983

    E-print Network

    Dh?5ooobl Risø-Rr509 Environmental Radioactivity in Denmark in 1983 A. Aarkrog, S. Boelskifte, L, Denmark June 1984 #12;ERRATA to RIS�-R-509 Environmental Radioactivity in Denmark in 1983. p 16 Table 3,4.3., and 4.4.5. show the tritium content in sea water. #12;Risø-R-509 ENVIRONMENTAL RADIOACTIVITY IN DENMARK

  10. Radioactive isotopes in Danish drinking water

    E-print Network

    Radioactive isotopes in Danish drinking water Sven P. Nielsen Risø National Laboratory Working OF INVESTIGATION 11 3 DESCRIPTION OF INVESTIGATION 12 4 RADIOACTIVITY IN DRINKING WATER 13 5 SAMPLING 15 6 ANALYTICAL METHODS 16 6.1 TOTAL ALPHA AND BETA RADIOACTIVITY 16 6.2 URANIUM 17 6.3 RADIUM 17 6.4 RADON 18 7

  11. Radioactivity in Food and the Environment, 1995

    E-print Network

    Radioactivity in Food and the Environment, 1995 Ministry of Agriculture, Fisheries and Food, 1996 RIFE - 1 #12;#12;1 MINISTRY OF AGRICULTURE, FISHERIES AND FOOD Radioactivity in Food information previously issued in the Terrestrial Radioactivity Monitoring Report (TRAMP) and the Aquatic

  12. Riso-R-489LK Environmental Radioactivity

    E-print Network

    E ~ ~, ~ Riso-R-489·LK Environmental Radioactivity in Greenland in 1982 A. Aarkrog, Henning Roskilde, Denmark July 1963 #12;Risø-R-489 ENVIRONMENTAL RADIOACTIVITY IN GREENLAND IN 1982 A. Aarkrog Abstract. Measurements of fallout radioactivity in Greenland in 1982 are reported. Strontium-90 (and Cesium

  13. Environmental Radioactivity in the Faroes in 1982

    E-print Network

    D Radioactivity in the Faroes in 1982 A. Aarkrog, H. Dahlgaard, L. Ha;Risø-R-488 ENVIRONMENTAL RADIOACTIVITY IN THE FAROES IN 1982 A. Aarkrog, H. Dahlgaard, L. Hallstadius radioactivity in the Faroes in 1982 are presented. Strontium-90 (and 137 Cs in most cases) was determined

  14. Radioactivity in Food and the Environment, 2003

    E-print Network

    Radioactivity in Food and the Environment, 2003 RIFE - 9 2004 #12;ISSN 1365-6414 Food Standards RadioactivityinFoodandtheEnvironment,2003 Scottish Environment ProtectionAgency Radioactive Substances Unit FOOD STANDARDS AGENCY SCOTTISH ENVIRONMENT PROTECTION AGENCY Radioactivity in Food and the Environment

  15. Radioactivity in Food and the Environment, 2004

    E-print Network

    Radioactivity in Food and the Environment, 2004 RIFE - 10 2005 #12;Food Standards Agency EmergencyFoodandtheEnvironment,2004 Scottish Environment ProtectionAgency Radioactive Substances Unit Erskine Court The Castle ENVIRONMENT PROTECTION AGENCY Radioactivity in Food and the Environment, 2004 RIFE - 10 October 2005 #12

  16. Radioactivity in Food and the Environment, 1999

    E-print Network

    Radioactivity in Food and the Environment, 1999 RIFE - 5 2000 SCOTTISH ENVIRONMENT PROTECTION AGENCY #12;1 FOOD STANDARDS AGENCY SCOTTISH ENVIRONMENT PROTECTION AGENCY Radioactivity in Food radiological.surveillance@foodstandards.gsi.gov.uk) and the Policy Co-ordination (Radioactive Substances) Group

  17. Ris-R-571(EX) Environmental Radioactivity

    E-print Network

    Risø-R-571(EX) Environmental Radioactivity in the North Atlantic Region Including the Faroe Islands Radioactivity RisoR5; in the North Atlantic Region Including the Faroe Islands and Greenland. 1988 and 1989 A;Abstract Measurements of fallout radioactivity in the North Atlantic region including Faroe Islands

  18. Radioactive Target Detection Using Wireless Sensor Network

    E-print Network

    Zhang, Tonglin

    Chapter 31 Radioactive Target Detection Using Wireless Sensor Network Tonglin Zhang Abstract The detection of radioactive target is becoming more important recently in public safety and national security can simultaneously detect and locate the radioactive target in the area. Our simulation results have

  19. Radioactivity in Food and the Environment, 2005

    E-print Network

    Radioactivity in Food and the Environment, 2005 RIFE - 11 2006 #12;Food Standards Agency EmergencyFoodandtheEnvironment,2005 Scottish Environment Protection Agency Radioactive Substances Unit Erskine Court The Castle ENVIRONMENT PROTECTION AGENCY Radioactivity in Food and the Environment, 2005 RIFE - 11 October 2006 #12

  20. Radioactivity in Food and the Environment, 2006

    E-print Network

    Radioactivity in Food and the Environment, 2006 RIFE - 12 2007 #12;1 ENVIRONMENT AGENCY ENVIRONMENT AND HERITAGE SERVICE FOOD STANDARDS AGENCY SCOTTISH ENVIRONMENT PROTECTION AGENCY Radioactivity in Food.surveillance@ foodstandards.gsi.gov.uk) · In Scotland, the Radioactive Substances Unit of SEPA (radiologicalmonitoring

  1. RADIOACTIVE METALLOFULLERENES: HOT ATOM CHEMISTRY ASPECTS.

    E-print Network

    Titov, Anatoly

    RADIOACTIVE METALLOFULLERENES: HOT ATOM CHEMISTRY ASPECTS. Yu.S.Grushko, M.A. Khodorkovski, V, in radioactive form, endometallofullerenes become the subject of new branch of radiochemistry and materials studies and monitoring of 1 #12;chemical properties of metallofullerenes, in technology of radioactive

  2. Radioactive Materials Manual Scope and Applicability

    E-print Network

    Rhoads, James

    Radioactive Materials Manual Scope and Applicability Procedures and information in this manual apply to all personnel working at or visiting ASU who procure, utilize and/or dispose of radioactive material. Radioactive material covered includes all sealed and unsealed sources. Sealed sources

  3. Radioactivity in Food and the Environment, 1998

    E-print Network

    Radioactivity in Food and the Environment, 1998 RIFE - 4 1999 SCOTTISH ENVIRONMENT PROTECTION SCOTTISH ENVIRONMENT PROTECTION AGENCY Radioactivity in Food and the Environment, 1998 RIFE - 4 September Co-ordination (Radioactive Substances) Group of SEPA for data relating to Scotland (web site www

  4. I>KO>OOOO2& Environmental Radioactivity

    E-print Network

    I>KO>OOOO2& Risø-R-564 IKJJj Environmental Radioactivity in the North Atlantic Region Including;Environmental Radioactivity *** in the North Atlantic Region Including the Faroe Islands and Greenland. 1987 A, Norway ** International Laboratory of Marine Radioactivity, Monaco Risø National Laboratory, DK-4000

  5. Radioactive Waste Management BasisApril 2006

    SciTech Connect

    Perkins, B K

    2011-08-31

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

  6. Public attitudes about radioactive waste

    SciTech Connect

    Bisconti, A.S. [Council for Energy Awareness, Washington, DC (United States)

    1992-12-31

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

  7. Radioactive fuel cell storage rack

    SciTech Connect

    Holtz, M.; Singh, K.P.

    1983-05-03

    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.

  8. Nuclear structure from radioactive decay

    NASA Astrophysics Data System (ADS)

    Wood, J. L.

    1991-09-01

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

  9. Environmental Geochemistry of Radioactive Contamination

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

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

  10. Stratospheric Mixing from Radioactive Fallout

    Microsoft Academic Search

    W. F. Libby; C. E. Palmer

    1960-01-01

    The radioactive fallout during 1959 shows that the Russian October 1958 debris dominated the northern hemisphere and came down with a residence time corresponding to about 8 months. The rest of the world had a steady fallout rate of about .06 mC\\/miS\\/inch of rain throughout the year, whereas values for the northern hemisphere came down to this value in the

  11. Radioactive substances in tap water.

    PubMed

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

    2014-01-01

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

  12. Radioactivity in the Great Lakes.

    PubMed

    Joshi, S R

    1991-03-01

    Studies of radioactivity in the Laurentian Great Lakes are reviewed to evaluate the impact of radionuclide dissemination on the world's foremost freshwater aquatic ecosystem. The status of radiologically-degraded areas is also reported. Significant amounts of radioactivity are stored in the basin, which has numerous nuclear reactors as well as uranium mine waste areas. The prevailing low levels of artificially-produced radionuclides, arising largely from previous fallout inputs, provide very little radiation dose to the area residents consuming lake water. The interlake transport of radionuclides is adequately described by existing models, though some refinement of the source term is needed. Revised estimates of fallout over each lake are given, but no data are available to estimate drainage basin contributions. Only limited information is available on the dispersal of radioactive pollutants. The influence of chemical parameters on radionuclide cycling has been extensively investigated in Lake Michigan and, to a lesser degree, in Lake Ontario. The need for developing a radiological objective for fish becomes apparent from an assessment of the very few data collected thus far on the biological and dosimetric aspects. Several research and monitoring needs are also identified. PMID:2063188

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

    PubMed

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

    2013-06-01

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

  14. Radioactivity

    SciTech Connect

    Baratta, E.J. [Winchester Engineering and Analytical Center, Winchester, MA (United States)

    1997-01-01

    Cesium-134 and -137 in Foods, Gamma-Ray Spectrophotometric Methods. The method entitled {open_quotes}Cs-134 and Cs-137 in Foods, Gamma-Ray Spectrophotometric Method{close_quotes} has been adopted official first action, with minor revisions. Iodine 131: The method {open_quotes}Iodine-131 in Milk, Radiochemical Separation Method{close_quotes} has been accepted by the Committee on Residues and Related Topics and has been recommended to the Methods Committee for adoption first action. Search is continuing for a new Associated Referee. Plutonium-239: The Associate Referee is doing a literature search for a method for the determination of plutonium in foods. When one is selected, she will prepared a protocol for a collaborative study and submit it for approval. Radium-228: Search is ongoing for a new Associate Referee. When one is appointed, a method should be selected and tested. Strontium-89 and -90: The Associate Referee is investigating methods using resin discs and/or resin columns for these radionuclides. These methods are now being used in analyses for strontium-89 and -90 in water. She will now attempt to apply it to milk. If successful, she will prepare a protocol for a collaborative study and submit it for approval. Tritium: Search is continuing for a new Associate Referee for this topic.

  15. Radioactivity

    SciTech Connect

    Baratta, E.J. [Food and Drug Administration, Winchester, MA (United States)

    1996-01-01

    This report of the General Referee was presented at the 109th AOAC International Annual Meeting, September 17-21, 1995 in Nashville, Tennessee. The author reports the standing of the review process for six methods concerned with the analysis of radionuclides in foods or the environment.

  16. Radioactivity

    SciTech Connect

    Baratta, E.J.

    1987-01-01

    This report of the General Referee was presented at the 100th AOAC Annual International Meeting, Sept. 15-18, 1986, at Scottsdale, AZ. The method for determining cesium-137 and iodine-131 in milk and other foods by gamma-ray spectroscopy has been adopted official first action. Results have been received from 5 collaborators. A sixth collaborator was found and is in the process of analyzing the sample. When all results are in, the Associate Referee will perform a statistical analysis of the data. Other topics of interest include; plutonium; radium-228; and strontium-89 and -90. Recommendations are included which were reviewed by the Committee on Residues.

  17. Radioactive Waste Management BasisSept 2001

    SciTech Connect

    Goodwin, S S

    2011-08-31

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

  18. Radioactive waste sampling supports processing

    SciTech Connect

    Nance, T.A.

    1997-03-01

    This article describes several new sampling and deployment devices for remote sampling of stored radioactive waste. The tools were developed to determine the chemical characteristics of waste material prior to taking steps for waste processing. Topics covered include the following: the challenge of the waste tank environment; tool criteria for the design; innovative sampling and deployment devices. The following devices were discussed individually: bottom suction sampling device, floating waste sampling device, sample scoop device, sludge/solids sampling device, wall scrape sampling device, counterweight boom deployment device, remote deployment vehicle, sampling arm deployment device. 3 figs.

  19. Radioactive beam science, past, present and future

    NASA Astrophysics Data System (ADS)

    Tanihata, Isao

    2008-10-01

    Since high-energy radioactive nuclei were used for collision measurements, many discoveries in physics and many inventions in technique of producing and delivering radioactive beam have been made. In this paper, firstly, I briefly review developments in radioactive beam science and then show a close relation between development in technology and physics. Based on such consideration, I discuss the probable best scheme of radioactive ion beam production for studies of r-process that is considered to be one of the most important and exciting subjects for the future.

  20. Radioactive Waste: Resources for Environmental Literacy

    NSDL National Science Digital Library

    Environmental Literacy Council

    2007-05-16

    Since World War II, hundreds of thousands of tons of radioactive materials have been produced in the United States. How we will dispose of nuclear waste is a controversial issue with a large technical component. This book provides a useful resource for enhancing student understanding of the physics of radioactivity as well as the storage and disposal of radioactive waste. It encourages students to discuss these complex environmental issues using arguments based on the science behind issues related to radioactivity, technology, risk assessment, and tradeoffs.

  1. Radioactive material package seal tests

    SciTech Connect

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

    1990-01-01

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

  2. Charge Breeding of Radioactive Ions

    E-print Network

    Wenander, F J C

    2013-01-01

    Charge breeding is a technique to increase the charge state of ions, in many cases radioactive ions. The singly charged radioactive ions, produced in an isotope separator on-line facility, and extracted with a low kinetic energy of some tens of keV, are injected into a charge breeder, where the charge state is increased to Q. The transformed ions are either directed towards a dedicated experiment requiring highly charged ions, or post-accelerated to higher beam energies. In this paper the physics processes involved in the production of highly charged ions will be introduced, and the injection and extraction beam parameters of the charge breeder defined. A description of the three main charge-breeding methods is given, namely: electron stripping in gas jet or foil; external ion injection into an electron-beam ion source/trap (EBIS/T); and external ion injection into an electron cyclotron resonance ion source (ECRIS). In addition, some preparatory devices for charge breeding and practical beam delivery aspects ...

  3. Cosmic radioactivity and INTEGRAL results

    NASA Astrophysics Data System (ADS)

    Diehl, Roland

    2014-05-01

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

  4. Magic radioactivity of 252Cf

    E-print Network

    M. Mirea; D. S. Delion; A. Sandulescu

    2010-03-31

    We show that the sharp maximum corresponding to 107Mo in the fragment distribution of the 252Cf cold fission is actually a Sn-like radioactivity, similar to other decay processes in which magic nuclei are involved, namely alpha-decay and heavy cluster emission, also called Pb-like radioactivity. It turns out that the mass asymmetry degree of freedom has a key role in connecting initial Sn with the final Mo isotopes along the fission path. We suppose the cold rearrangement of nucleons within the framework of the two center shell model, in order to compute the cold valleys in the charge equilibrated fragmentation potential. The fission yields are estimated by using the semiclassical penetration approach. We consider five degrees of freedom, namely the inter-fragment distance, the shapes of fragments, the neck parameter and mass asymmetry. We found an isomeric minimum between the internal and external barriers. It turns out that the inner cold valley of the total potential energy is connected to the double magic isotope 132Sn

  5. Induced radioactivity in LDEF components

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  6. Cosmic radioactivity and INTEGRAL results

    SciTech Connect

    Diehl, Roland [Max Planck Institut für Extraterrestrische Physik, D-85748 Garching, Germany and Excellence Cluster Origin and Evolution of the Universe', D-85748 Garching (Germany)

    2014-05-02

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

  7. Radioactivity in the galactic plane

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

  8. MARSAME Appendix B B. SOURCES OF BACKGROUND RADIOACTIVITY

    E-print Network

    MARSAME Appendix B B. SOURCES OF BACKGROUND RADIOACTIVITY B.1 Introduction Background radioactivity can complicate the disposition decision for M&E. Background radioactivity may be the result of environmental radioactivity, inherent radioactivity, instrument noise, or some combination of the three. Special

  9. Identifying Mixed Chemical and Radioactive Waste Mixed waste is: any waste material containing both radioactive materials

    E-print Network

    Straight, Aaron

    Identifying Mixed Chemical and Radioactive Waste Mixed waste is: any waste material containing both as noted on the list, you do not have a mixed waste and it may be managed as a normal radioactive waste radioactive waste after initially dating the container, the hold for decay time is extended, but you cannot

  10. Natural radioactivity in Italian ceramic tiles

    Microsoft Academic Search

    S. Righi; A. Albertazzi; R. Guerra; M. Jeyapandian; S. Verità

    2009-01-01

    and, therefore, reference is often made to radium instead of uranium (EC, 1999). The knowledge of the natural radioactivity of building materials is important for the determination of population exposure to radiations, as most of the people spend ~80% of their time indoors (UNSCEAR, 1993). High levels of radioactivity in construction materials can increase external and internal indoor exposure. Currently,

  11. HOTSPOT. Gaussian Dispersion Model for Radioactive Materials

    Microsoft Academic Search

    Homann

    1995-01-01

    The HOTSPOT Health Physics codes were created to provide Health Physics personnel with a fast, field-portable calculational tool for evaluating accidents involving radioactive materials. HOTSPOT codes are a first-order approximation of the radiation effects associated with the atmospheric release of radioactive materials. HOTSPOT programs are reasonably accurate for a timely initial assessment. More importantly, HOTSPOT codes produce a consistent output

  12. RECENT RESULTS FROM ALPINE AIR RADIOACTIVITY MEASUREMENTS

    Microsoft Academic Search

    1960-01-01

    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

  13. Overview of Radioactive Waste Disposal at Sea

    Microsoft Academic Search

    Dominique Calmet

    1992-01-01

    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

  14. Proposed goals for radioactive waste management

    Microsoft Academic Search

    W. P. Bishop; D. H. Frazier; I. R. Hoos; P. E. McGrath; D. S. Metlay; W. C. Stoneman; R. A. Watson

    1977-01-01

    Goals are proposed for the national radioactive waste management program to establish a policy basis for the guidance and coordination of the activities of government, business, and academic organizations whose responsibility it will be to manage radioactive wastes. The report is based on findings, interpretations, and analyses of selected primary literature and interviews of personnel concerned with waste management. Public

  15. Elements of a radioactive waste management course

    Microsoft Academic Search

    Fentiman

    1994-01-01

    The demand for scientists, engineers, and technicians with expertise in radioactive waste management is growing rapidly. Many universities, government agencies, and private contractors are developing courses in radioactive waste management. Two such courses have been developed at The Ohio State University. In support of that course development, two surveys were conducted. One survey went to all nuclear engineering programs in

  16. Radioactive waste management: 1963-1984

    Microsoft Academic Search

    B R Hookway

    1984-01-01

    A broad-brush description of radioactive waste management over the past twenty-one years is given. It is set in the context of statutory requirements of the Radioactive Substance Act 1960, which became law in 1983. The Act is looked at critically and an attempt is made to demonstrate that where there were failings in the field of waste management, these were

  17. Pb-Radioactivity in superheavy elements

    E-print Network

    Sushil Kumar

    2011-10-24

    The Pb-radioactivity in the superheavy mass region is studied within the frame work of PCM model,the calculation of Pb-Radioactivity looks favorably for the cluster decay studies in superheavy mass region as in the heavy mass region.

  18. RADIOACTIVE WASTES--ORIGIN, HAZARDS AND TREATMENT

    Microsoft Academic Search

    Kinell

    1962-01-01

    When energy is produced by nuclear fission, radioactive wastes also are ; obtained. These are formed in all steps from the mining of uranium ore to the ; operation of reactors. They also arise from the application of radioactive ; nuclides in industry and research. Due to the action of the radiation on the ; different organs in the human

  19. 49 CFR 172.436 - RADIOACTIVE WHITE-I label.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 2010-10-01 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:...

  20. RADIOACTIVE ELEMENT REMOVAL FROM WATER USING GRAPHENE OXIDE (GO)

    E-print Network

    Concklin, Joshua Paul

    2013-12-19

    radioactive materials from wastewater. For now, this Nano-technological breakthrough of capturing radioactive materials on GO, burning the GO and disposing of the compacted radioactive waste could invigorate the mining business while offering attractive...

  1. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false High-level radioactive waste. 227.30 Section 227.30 Protection... Definitions § 227.30 High-level radioactive waste. High-level radioactive waste means the aqueous waste resulting...

  2. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false High-level radioactive waste. 227.30 Section 227.30 Protection... Definitions § 227.30 High-level radioactive waste. High-level radioactive waste means the aqueous waste resulting...

  3. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 false High-level radioactive waste. 227.30 Section 227.30 Protection... Definitions § 227.30 High-level radioactive waste. High-level radioactive waste means the aqueous waste resulting...

  4. 40 CFR 147.3005 - Radioactive waste injection wells.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Radioactive waste injection wells. 147.3005...Mexico Tribes § 147.3005 Radioactive waste injection wells. Notwithstanding...of wells used to dispose of radioactive waste (as defined in 10 CFR...

  5. 40 CFR 147.3005 - Radioactive waste injection wells.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Radioactive waste injection wells. 147.3005...Mexico Tribes § 147.3005 Radioactive waste injection wells. Notwithstanding...of wells used to dispose of radioactive waste (as defined in 10 CFR...

  6. 40 CFR 147.3005 - Radioactive waste injection wells.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Radioactive waste injection wells. 147.3005...Mexico Tribes § 147.3005 Radioactive waste injection wells. Notwithstanding...of wells used to dispose of radioactive waste (as defined in 10 CFR...

  7. 40 CFR 147.3005 - Radioactive waste injection wells.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Radioactive waste injection wells. 147.3005...Mexico Tribes § 147.3005 Radioactive waste injection wells. Notwithstanding...of wells used to dispose of radioactive waste (as defined in 10 CFR...

  8. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 2014-07-01 false High-level radioactive waste. 227.30 Section 227.30 Protection... Definitions § 227.30 High-level radioactive waste. High-level radioactive waste means the aqueous waste resulting...

  9. 40 CFR 147.3005 - Radioactive waste injection wells.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Radioactive waste injection wells. 147.3005...Mexico Tribes § 147.3005 Radioactive waste injection wells. Notwithstanding...of wells used to dispose of radioactive waste (as defined in 10 CFR...

  10. Rev August 2006 Radiation Safety Manual Section 14 Radioactive Waste

    E-print Network

    Wilcock, William

    Rev August 2006 Radiation Safety Manual Section 14 ­ Radioactive Waste Page 14-1 Section 14 Radioactive Waste Contents A. Proper Collection, Disposal, and Packaging and Putrescible Animal Waste.........................14-8 a. Non-Radioactive Animal Waste

  11. 49 CFR 172.436 - RADIOACTIVE WHITE-I label.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2012-10-01 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:...

  12. 49 CFR 172.436 - RADIOACTIVE WHITE-I label.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2011-10-01 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:...

  13. 49 CFR 172.436 - RADIOACTIVE WHITE-I label.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 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:...

  14. 49 CFR 172.436 - RADIOACTIVE WHITE-I label.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 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:...

  15. 10 CFR 76.83 - Transfer of radioactive material.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...radioactive material. 76.83 Section 76.83 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.83 Transfer of radioactive material. (a) The Corporation may not transfer radioactive...

  16. 10 CFR 76.83 - Transfer of radioactive material.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...radioactive material. 76.83 Section 76.83 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.83 Transfer of radioactive material. (a) The Corporation may not transfer radioactive...

  17. 10 CFR 76.83 - Transfer of radioactive material.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...radioactive material. 76.83 Section 76.83 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.83 Transfer of radioactive material. (a) The Corporation may not transfer radioactive...

  18. 10 CFR 76.83 - Transfer of radioactive material.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...radioactive material. 76.83 Section 76.83 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.83 Transfer of radioactive material. (a) The Corporation may not transfer radioactive...

  19. 10 CFR 76.83 - Transfer of radioactive material.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...radioactive material. 76.83 Section 76.83 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.83 Transfer of radioactive material. (a) The Corporation may not transfer radioactive...

  20. 40 CFR 141.25 - Analytical methods for radioactivity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Analytical methods for radioactivity. 141.25 Section 141.25 ...141.25 Analytical methods for radioactivity. (a) Analysis for the following...determine compliance with § 141.66 (radioactivity) in accordance with the...

  1. 40 CFR 141.25 - Analytical methods for radioactivity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Analytical methods for radioactivity. 141.25 Section 141.25 ...141.25 Analytical methods for radioactivity. (a) Analysis for the following...determine compliance with § 141.66 (radioactivity) in accordance with the...

  2. 40 CFR 141.25 - Analytical methods for radioactivity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Analytical methods for radioactivity. 141.25 Section 141.25 ...141.25 Analytical methods for radioactivity. (a) Analysis for the following...determine compliance with § 141.66 (radioactivity) in accordance with the...

  3. 40 CFR 141.25 - Analytical methods for radioactivity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Analytical methods for radioactivity. 141.25 Section 141.25 ...141.25 Analytical methods for radioactivity. (a) Analysis for the following...determine compliance with § 141.66 (radioactivity) in accordance with the...

  4. Thermal treatment of organic radioactive waste

    SciTech Connect

    Chrubasik, A.; Stich, W. [NUKEM GmbH, Alzenau (Germany)

    1993-12-31

    The organic radioactive waste which is generated in nuclear and isotope facilities (power plants, research centers and other) must be treated in order to achieve a waste form suitable for long term storage and disposal. Therefore the resulting waste treatment products should be stable under influence of temperature, time, radioactivity, chemical and biological activity. Another reason for the treatment of organic waste is the volume reduction with respect to the storage costs. For different kinds of waste, different treatment technologies have been developed and some are now used in industrial scale. The paper gives process descriptions for the treatment of solid organic radioactive waste of low beta/gamma activity and alpha-contaminated solid organic radioactive waste, and the pyrolysis of organic radioactive waste.

  5. Apparatus and method for radioactive waste screening

    DOEpatents

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

    2012-09-04

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

  6. Direct reactions with radioactive beams

    NASA Astrophysics Data System (ADS)

    Bonaccorso, Angela

    2014-07-01

    Since the first measurements in the 80's of total reaction cross sections from radioactive beams up to the most recent and advanced exclusive experiments for dripline unbound nuclei, our understanding of exotic nuclei has greatly evolved. This has been possible through a joint effort in the description of the reaction mechanisms and of the underlying nuclear structure. Most exotic nuclei are weakly bound due to the excess of either neutrons or protons and they breakup easily in peripheral reactions. We will discuss in this paper the mechanism responsible for nuclear and Coulomb breakup. Some open problems will be discussed in detail, such as kinematical effects on core parallel momentum distributions and the possibility and consequences that such cores be themselves weakly bound. A general framework for the reaction theory will be used, based on a time dependent perturbation theory approach. Its eikonal limit will be also mentioned.

  7. Method for immobilizing radioactive iodine

    DOEpatents

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

    1980-01-01

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

  8. Microbiological treatment of radioactive wastes

    SciTech Connect

    Francis, A.J.

    1992-12-31

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

  9. Radioactive wastes management development in Chile

    SciTech Connect

    Mir, S.A.; Cruz, P.F.; Rivera, J.D.; Jorquera, O.H.

    1994-12-31

    A Facility for immobilizing and conditioning of radioactive wastes generated in Chile, has recently started in operation. It is a Radioactive Wastes Treatment Plant, RWTP, whose owner is Comision Chilena de Energia Nuclear, CCHEN. A Storgement Building of Conditioned Wastes accomplishes the facility for medium and low level activity wastes. The Project has been carried with participation of chilean professionals at CCHEN and Technical Assistance of International Atomic Energy Agency, IAEA. Processes developed are volume reduction by compaction; immobilization by cementation and conditioning. Equipment has been selected to process radioactive wastes into a 200 liters drum, in which wastes are definitively conditioned, avoiding exposition and contamination risks. The Plant has capacity to treat low and medium activity radioactive wastes produced in Chile due to Reactor Experimental No. 1 operation, and annex Laboratories in Nuclear Research Centers, as also those produced by users of nuclear techniques in Industries, Hospitals, Research Centers and Universities, in the whole country. With the infrastructure developed in Chile, a centralization of Radioactive Wastes Management activities is achieved. A data base system helps to control and register radioactive wastes arising in Chile. Generation of radioactive wastes in Chile, has found solution for the present production and that of near future.

  10. Natural radioactivity in groundwater--a review.

    PubMed

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

    2011-12-01

    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

  11. A radioactive metal processing industry perspective source.

    PubMed

    Johnson, A

    2006-11-01

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

  12. Influence of radioactivity on surface interaction forces.

    PubMed

    Walker, M E; McFarlane, J; Glasgow, D C; Chung, E; Taboada-Serrano, P; Yiacoumi, S; Tsouris, C

    2010-10-15

    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(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. PMID:20650464

  13. Influence of Radioactivity on Surface Interaction Forces

    SciTech Connect

    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

    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.

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

    NASA Astrophysics Data System (ADS)

    Gelletly, W.

    2001-05-01

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

  15. Radioactive anomaly discrimination from spectral ratios

    DOEpatents

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

    2013-08-20

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

  16. Radioactivities related to coal mining.

    PubMed

    Seddeek, Mostafa K; Sharshar, Taher; Ragab, Hossam S; Badran, Hussein M

    2005-08-01

    Natural radioactivity concentrations due to the coal mining in Gabal El-Maghara, North Sinai, Egypt, were determined using gamma-ray spectroscopy. Coal, water and soil samples were investigated in this study. The (226)Ra, (232)Th and (40)K activity concentrations in coal before extraction were 18.5 +/- 0.5, 29.5 +/- 1.2 and 149.0 +/- 8.4 Bq kg(-1), respectively. These concentrations were reduced to 18-22% after extraction due to the clay removal of the coal ore. The activity contents of the water and soil samples collected from the surrounding area did not show any evidence of enhancement due to the mining activities. Absorbed dose rate and effective dose equivalent in the mine environment were 29.4 nGy h(-1) and 128.0 microSv a(-1), respectively. The measured activity concentrations in the mine environment and the surrounding areas (5 km away from the mine) are similar to that found in other regions in North and South Sinai. Based on the measurements of gamma-ray emitting radionuclides, the mine activity does not lead to any enhancement in the local area nor represents any human risk. PMID:16049576

  17. The Discovery of Artificial Radioactivity

    NASA Astrophysics Data System (ADS)

    Guerra, Francesco; Leone, Matteo; Robotti, Nadia

    2012-03-01

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

  18. Is Radioactive Decay Really Exponential?

    E-print Network

    Philip J. Aston

    2012-04-26

    Radioactive decay of an unstable isotope is widely believed to be exponential. This view is supported by experiments on rapidly decaying isotopes but is more difficult to verify for slowly decaying isotopes. The decay of 14C can be calibrated over a period of 12,550 years by comparing radiocarbon dates with dates obtained from dendrochronology. It is well known that this approach shows that radiocarbon dates of over 3,000 years are in error, which is generally attributed to past variation in atmospheric levels of 14C. We note that predicted atmospheric variation (assuming exponential decay) does not agree with results from modelling, and that theoretical quantum mechanics does not predict exact exponential decay. We give mathematical arguments that non-exponential decay should be expected for slowly decaying isotopes and explore the consequences of non-exponential decay. We propose an experimental test of this prediction of non-exponential decay for 14C. If confirmed, a foundation stone of current dating methods will have been removed, requiring a radical reappraisal both of radioisotope dating methods and of currently predicted dates obtained using these methods.

  19. Current status of radioactive waste disposal

    Microsoft Academic Search

    G. R. Choppin; P. J. Wong

    1996-01-01

    This paper describes the technical issues involved in the development of a feasible solution toward permanent radioactive waste disposal. Recent progress on internationally collaborative research efforts concerning the multibarrier concept, in situ experiments, computer modeling and natural analogues are discussed.

  20. Radioactivity in man: levels, effects and unknowns

    SciTech Connect

    Rundo, J.

    1980-01-01

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

  1. Radioactive Dating: A Method for Geochronology.

    ERIC Educational Resources Information Center

    Rowe, M. W.

    1985-01-01

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

  2. Environmental aspects of commercial radioactive waste management

    SciTech Connect

    Not Available

    1979-05-01

    Environmental effects (including accidents) associated with facility construction, operation, decommissioning, and transportation in the management of commercially generated radioactive waste were analyzed for plants and systems assuming a light water power reactor scenario that produces about 10,000 GWe-yr through the year 2050. The following alternative fuel cycle modes or cases that generate post-fission wastes requiring management were analyzed: a once-through option, a fuel reprocessing option for uranium and plutonium recycle, and a fuel reprocessing option for uranium-only recycle. Volume 1 comprises five chapters: introduction; summary of findings; approach to assessment of environmental effects from radioactive waste management; environmental effects related to radioactive management in a once-through fuel cycle; and environmental effects of radioactive waste management associated with an LWR fuel reprocessing plant. (LK)

  3. Computed tomography of radioactive objects and materials

    NASA Astrophysics Data System (ADS)

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

    1990-12-01

    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.

  4. Issues of natural radioactivity in phosphates

    SciTech Connect

    Schnug, E.; Haneklaus, S. [Institute of Plant Nutrition and Soil Science, Braunschweig (Germany); Schnier, C. [GKSS-Research Centre, Geesthacht (Germany); Scholten, L.C. [KEMA, Arnhem (Netherlands)

    1996-12-31

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

  5. Overflow of Radioactive Water from K Basins

    SciTech Connect

    RITTMANN, P.D.

    1999-10-06

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

  6. 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,...

  7. RADIOACTIVITY STANDARDS DISTRIBUTION PROGRAM, 1978-1979

    EPA Science Inventory

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

  8. Principles for Sampling Airborne Radioactivity from Stacks

    SciTech Connect

    Glissmeyer, John A.

    2010-10-18

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

  9. Vitrification of hazardous and radioactive wastes

    SciTech Connect

    Bickford, D.F.; Schumacher, R.

    1995-12-31

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

  10. Transport of Radioactive Material by Alpha Recoil

    SciTech Connect

    Icenhour, A.S.

    2005-05-19

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

  11. Sorting and disposal of hazardous laboratory Radioactive waste

    E-print Network

    Maoz, Shahar

    Sorting and disposal of hazardous laboratory waste Radioactive waste Solid radioactive waste or in a Perspex box. Liquid radioactive waste collect in a screw-cap plastic bottle, ½ or 1 L size. Place bottles in a tray to avoid spill Final disposal of both solid and radioactive waste into the yellow barrel

  12. RADIOACTIVITY 1997 BNL Site Environmental Report 4 -1

    E-print Network

    RADIOACTIVITY 1997 BNL Site Environmental Report 4 - 1 Chapter 4 RADIOACTIVITY To define radiation by materials such as paper and have a range in air of only an inch or so. Naturally occurring radioactive of a few inches. Naturally occurring radioactive elements such as potassium-40 emit beta radiation. Gamma

  13. Radioactivity and X-rays Applications and health effects

    E-print Network

    Sahay, Sundeep

    Radioactivity and X-rays Applications and health effects by Thormod Henriksen #12;Preface as the release of radioactivity from reactor accidents and fallout from nuclear explosions in the atmosphere ­ 7 Chapter 2. What is radioactivity page 8 ­ 27 Chapter 3. Radioactive decay laws page 28 ­ 35

  14. s.haszeldine@ed.ac.uk Radioactive waste Cumbria 6, 7 Sept 2012 1 Geological disposal of radioactive

    E-print Network

    s.haszeldine@ed.ac.uk Radioactive waste Cumbria 6, 7 Sept 2012 1 Geological disposal of radioactive_and_Copeland.html #12;Nuclear power s.haszeldine@ed.ac.uk Radioactive waste Cumbria 6, 7 Sept 2012 2 First civil nuclear #12;Keeping hot fuel on the surface for 50-150 years s.haszeldine@ed.ac.uk Radioactive waste Cumbria 6

  15. Public involvement in radioactive waste management decisions

    SciTech Connect

    NONE

    1994-04-01

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

  16. CHAPTER 5-RADIOACTIVE WASTE MANAGEMENT

    SciTech Connect

    Marra, J.

    2010-05-05

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

  17. Environmental radioactivity in the Arctic, Antarctic

    SciTech Connect

    Palmer, H.

    1993-12-01

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

  18. Radioactive-ion-beam research at Livermore

    SciTech Connect

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

    1983-06-01

    The availability of radioactive ion beams represents a major advance in the capbaility to attack important problems of basic and applied nuclear physics. For the first time we are able to study nuclear reactions on nuclides outside the valley of stability. These nuclides represent about 80% of particle-stable isotopes. Questions of nuclear reaction mechanisms, nuclear properties of bound and continuum states, and basic symmetries for these unstable nuclides can therefore be answered by direct mesurement rather than by speculation. The applications of radioactive ion beams are widespread and extensive. In astrophysical studies, nuclear reactions of radioactive ion beams are essential to understanding a wide range of problems in energy generation, nucleosynthesis, neutrino effects, and the implications of gamma-ray astrophysical measurements. In material studies, the implantation of radioactive ions has already seen important use. Well defined beams of these ions will greatly increase the specifity and sensititivity of this technology. Radioactive ion beams may also have significant applications in medical diagnostics and therapy. Finally, standard sources of beta and gamma radiation can be prepared with much greater precision than formerly available.

  19. Laser decontamination of the radioactive lightning rods

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  20. Radioactive waste management in a hospital.

    PubMed

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

    2010-01-01

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

  1. Radioactive Waste Management in A Hospital

    PubMed Central

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

    2010-01-01

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

  2. Type A radioactive liquid sample packaging family

    SciTech Connect

    Edwards, W.S.

    1995-11-01

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

  3. Radioactive source security: the cultural challenges.

    PubMed

    Englefield, Chris

    2015-04-01

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

  4. The UK Committee on Radioactive Waste Management.

    PubMed

    Baverstock, Keith; Ball, David J

    2005-09-01

    The UK Committee on Radioactive Waste Management is charged with recommending to Government, by July 2006, options for the long term management of the UK's radioactive waste legacy. These options should inspire public confidence. Now, more than halfway into the time allotted, we, as two former members of the Committee, express our concerns at the wayward approach that has been adopted. The Committee has placed emphasis on gaining public confidence but this has been done at the expense of recruiting the best scientific expertise in the management of radioactive waste, an act which we believe will actually undermine public confidence. Furthermore, given also the immense importance of this decision to public safety, national security and the national interest, we believe urgent steps should be taken to review the Committee's process, its management and its sponsorship. PMID:16286694

  5. Low radioactivity spectral gamma calibration facility

    SciTech Connect

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

    1986-01-01

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

  6. Radioactive tank waste remediation focus area

    SciTech Connect

    NONE

    1996-08-01

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

  7. Wide range radioactive gas concentration detector

    DOEpatents

    Anderson, David F. (Los Alamos, NM)

    1984-01-01

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

  8. Radioactivity and electron acceleration in supernova remnants

    SciTech Connect

    Zirakashvili, V. N. [Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation, 142190 Troitsk, Moscow Region (Russian Federation); Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Aharonian, F. A. [Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

    2011-10-15

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

  9. Influence of Relic Neutrinos on Beta Radioactivity

    E-print Network

    A. G. Parkhomov

    2010-10-08

    Results of calculations of distribution and motion of dark matter are presented. Considering neutrino as one of the components of dark matter and taking into account peculiar features of the interactions of slow neutrinos with matter, allow to make the conclusion that they may have tangible manifestations not only in the depths of the Universe but also on the Earth. Experimental results confirming predicted effects are described, including periodic variations of the beta radioactivity as well as count rate bursts for a beta radioactive source placed at the focal point of a parabolic mirror. Based on the data of astronomical observations, estimates of the mass of the particles influencing on beta radioactivity (about 20 eV) and their flux density (about 10^13 particles/cm^2 s) have been made. The discrepancy between our mass estimate and the 2 eV limit for the neutrino mass, established in the tritium experiments, is discussed.

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

    NASA Astrophysics Data System (ADS)

    Simoncini, Eugenio; Brucato, John Robert

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

  11. Decontamination of protective clothing against radioactive contamination.

    PubMed

    Vošahlíková, I; Otáhal, P

    2014-11-01

    The aim of this study is to describe the experimental results of external surface mechanical decontamination of the studied materials forming selected suits. Seven types of personal protective suits declaring protection against radioactive aerosol contamination in different price ranges were selected for decontamination experiments. The outcome of this study is to compare the efficiency of a double-step decontamination process on various personal protective suits against radioactive contamination. A comparison of the decontamination effectiveness for the same type of suit, but for the different chemical mixtures ((140)La in a water-soluble or in a water-insoluble compound), was performed. PMID:25084793

  12. Microwave processing of radioactive materials-I

    SciTech Connect

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

    1989-01-01

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

  13. Pump station for radioactive waste water

    DOEpatents

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

    2003-11-18

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

  14. Nondestructive measurement of environmental radioactive strontium

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  15. 77 FR 26991 - Low-Level Radioactive Waste Management Issues

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-08

    ...3150-AI92 Low-Level Radioactive Waste Management Issues AGENCY: Nuclear Regulatory...and Low-Level Radioactive Waste Management'' (76 FR 50500; August...Assessment Directorate, Division of Waste Management and Environmental...

  16. 77 FR 10401 - Low-Level Radioactive Waste Management Issues

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-22

    ...NRC-2011-0012] Low-Level Radioactive Waste Management Issues AGENCY: Nuclear Regulatory...assessment as part of its radioactive waste management decision-making. The DOE...Assessment Directorate, Division of Waste Management and Environmental...

  17. 48 CFR 52.223-7 - Notice of radioactive materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...quantity of activity, or the characteristics and composition of the radioactive material from deliveries under this contract...the quantity of activity, characteristics, and composition of the radioactive material have not changed; and...

  18. 48 CFR 52.223-7 - Notice of radioactive materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...quantity of activity, or the characteristics and composition of the radioactive material from deliveries under this contract...the quantity of activity, characteristics, and composition of the radioactive material have not changed; and...

  19. 10 CFR 76.81 - Authorized use of radioactive material.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...radioactive material. 76.81 Section 76.81 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.81 Authorized use of radioactive material. Unless otherwise authorized by law, the...

  20. 10 CFR 76.81 - Authorized use of radioactive material.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...radioactive material. 76.81 Section 76.81 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.81 Authorized use of radioactive material. Unless otherwise authorized by law, the...

  1. 10 CFR 76.81 - Authorized use of radioactive material.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...radioactive material. 76.81 Section 76.81 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.81 Authorized use of radioactive material. Unless otherwise authorized by law, the...

  2. 10 CFR 76.81 - Authorized use of radioactive material.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...radioactive material. 76.81 Section 76.81 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.81 Authorized use of radioactive material. Unless otherwise authorized by law, the...

  3. 10 CFR 76.81 - Authorized use of radioactive material.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...radioactive material. 76.81 Section 76.81 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) CERTIFICATION OF GASEOUS DIFFUSION PLANTS Safety § 76.81 Authorized use of radioactive material. Unless otherwise authorized by law, the...

  4. Canister arrangement for storing radioactive waste

    DOEpatents

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

    1980-04-23

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

  5. Annual Radioactive Waste Tank Inspection Program - 2000

    SciTech Connect

    West, W.R.

    2001-04-17

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

  6. Annual radioactive waste tank inspection program - 1999

    SciTech Connect

    Moore, C.J.

    2000-04-14

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

  7. Radioactive AirBorne Dusts in Japan

    Microsoft Academic Search

    T. Mamuro; A. Fujita; T. Matsunami; K. Yoshikawa; T. Azuma

    1962-01-01

    In order to find the reason for differing radioactivity of rainwater ; samples collected at nearby laboratories at the same time in the fall of l96l, ; autoradiographs were made of the air-borne dusts collected on large filter papers. ; Some of the resulting spots were extremely active, and it is concluded that the ; rainwater discrepancy is due to

  8. 2006 Nature Publishing Group Radioactive 26

    E-print Network

    California at Berkeley, University of

    . Excess 26 Mg found in meteorites shows that the hot disk-accretion phase of the presolar nebula was apparently characterized3,4 by an amount of radioactive 26 Al (relative to the stable 27 Al isotope are indeed distributed throughout the Galaxy, Galactic rotation will cause Doppler shifts of the g-ray line

  9. Risk assessment criteria for radioactive waste disposal

    Microsoft Academic Search

    James O. Corbett

    1988-01-01

    The assessment of radioactive waste disposal options in terms of the annual risk to the critical group can lead to ambiguities, which arise largely in defining what is meant by the critical group. Radically different risk estimates can be obtained, depending on whether statistical averaging is carried out before or after the critical group is located in the time dimension.

  10. A sensitive cloud chamber without radioactive sources

    NASA Astrophysics Data System (ADS)

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

    2012-09-01

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

  11. Residual radioactivity in the Fermilab accelerator enclosures

    Microsoft Academic Search

    J. H. McCrary; H. H. Jr. Casebolt

    1976-01-01

    A self-propelled radiation survey vehicle is used to make periodic measurements of the radiation levels in the various Fermilab accelerator enclosures resulting from residual radioactivity induced by losses from the proton beam. The vehicle is equipped with instrumentation which provides a strip chart record of the radiation intensity as a function of position and the mean radiation intensity of a

  12. Method for decontamination of radioactive metal surfaces

    DOEpatents

    Bray, Lane A. (Richland, WA)

    1996-01-01

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

  13. Hazardous chemical and radioactive wastes at Hanford

    SciTech Connect

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

    1991-07-01

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

  14. Hazardous chemical and radioactive wastes at Hanford

    SciTech Connect

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

    1991-07-01

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

  15. Thyroid Cancer Following Exposure to Radioactive Iodine

    Microsoft Academic Search

    Jacob Robbins; Arthur B. Schneider

    2000-01-01

    Although external radiation is a well-known cause of human thyroid cancer, the risk from exposure of the thyroid gland to internal radiation is not well defined. This is of practical importance because of the extensive use of radioactive iodine in medical practice and the potential for release of iodine radionuclides into the environment. The purpose of this review is to

  16. Canister arrangement for storing radioactive waste

    DOEpatents

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

    1982-01-01

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

  17. The induced radioactivity background in OSSE

    Microsoft Academic Search

    S. J. R. Battersby; J. J. Quenby; C. S. Dyer; P. R. Truscott; N. D. A. Hammond; C. Comber

    1994-01-01

    An updated calculation of the induced radioactivity background is presented, using Monte Carlo radiation transport codes to give isotope production rates in OSSE, and rewritten codes for the determination of decay rates and summation of isotope response functions. OSSE's charged particle monitor rates are now used for trapped proton fluences, and a number of nuclides have been added to the

  18. Physics with energetic radioactive ion beams

    SciTech Connect

    Henning, W.F.

    1996-12-31

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

  19. Method for decontamination of radioactive metal surfaces

    DOEpatents

    Bray, L.A.

    1996-08-13

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

  20. 49 CFR 172.556 - RADIOACTIVE placard.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  1. 49 CFR 172.556 - RADIOACTIVE placard.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  2. 49 CFR 172.556 - RADIOACTIVE placard.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  3. 49 CFR 172.556 - RADIOACTIVE placard.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  4. 49 CFR 172.556 - RADIOACTIVE placard.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  5. Simplifying the Mathematical Treatment of Radioactive Decay

    ERIC Educational Resources Information Center

    Auty, Geoff

    2011-01-01

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

  6. (Low-level radioactive waste management techniques)

    Microsoft Academic Search

    S. D. Van Hoesen; J. M. Kennerly; L. C. Williams; W. N. Lingle; M. S. Peters; G. R. Darnell; Du Pont de Nemours

    1988-01-01

    The US team consisting of representatives of Oak Ridge National Laboratory (ORNL), Savannah River plant (SRP), Idaho National Engineering Laboratory (INEL), and the Department of Energy, Oak Ridge Operations participated in a training program on French low-level radioactive waste (LLW) management techniques. Training in the rigorous waste characterization, acceptance and certification procedures required in France was provided at Agence Nationale

  7. Safe transport of radioactive materials in Egypt

    NASA Astrophysics Data System (ADS)

    El-Shinawy, Rifaat M. K.

    1994-07-01

    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

  8. High-level radioactive wastes. Supplement 1

    SciTech Connect

    McLaren, L.H. (ed.)

    1984-09-01

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

  9. A Sensitive Cloud Chamber without Radioactive Sources

    ERIC Educational Resources Information Center

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

    2012-01-01

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

  10. Chapter 25: Radioactivity, Nuclear Processes, and Applications

    E-print Network

    Hart, Gus

    ? How do the nuclear potential energies compare? How do nuclear forces explain this? Fusion CombiningChapter 25: Radioactivity, Nuclear Processes, and Applications 1 The discovery of nuclear chain · Contains positively charged protons. · Held together by the Nuclear Strong ForceNuclear Strong Force. James

  11. Annual radioactive waste tank inspection program: 1995

    SciTech Connect

    McNatt, F.G. Sr.

    1996-04-01

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

  12. ANNUAL RADIOACTIVE WASTE TANK INSPECTION PROGRAM 2008

    SciTech Connect

    West, B.; Waltz, R.

    2009-06-11

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

  13. Ion beam analysis of radioactive samples

    NASA Astrophysics Data System (ADS)

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

    2009-06-01

    The nuclear microprobe facility of the Pierre 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.

  14. Introduction to naturally occurring radioactive material

    Microsoft Academic Search

    Egidi

    1997-01-01

    Naturally occurring radioactive material (NORM) is everywhere; we are exposed to it every day. It is found in our bodies, the food we eat, the places where we live and work, and in products we use. We are also bathed in a sea of natural radiation coming from the sun and deep space. Living systems have adapted to these levels

  15. Recycling and Reuse of Radioactive Materials

    ERIC Educational Resources Information Center

    O'Dou, Thomas Joseph

    2012-01-01

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

  16. Annual Radioactive Waste Tank Inspection Program - 1998

    SciTech Connect

    McNatt, F.G.

    1999-10-27

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

  17. POLLUTION OF RESERVOIR SURFACES WITH RADIOACTIVE SUBSTANCES

    Microsoft Academic Search

    S. M. Drachev; A. A. Bylinkina

    1960-01-01

    A concentration of radioactive substances was observed on the surface of ; practically clean reservoirs and rivers which are polluted with industrial ; effluents. The concentration was assessed by collection of surface films in the ; reservoirs and investigation of the foam collected in rivers, lakes, and ; reservoirs, The concentration of beta radiating substances in the foam increases ;

  18. Annual radioactive waste tank inspection program - 1992

    SciTech Connect

    McNatt, F.G.

    1992-12-31

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

  19. Safety Aspects in Radioactive Waste Management

    Microsoft Academic Search

    Peter W. Brennecke

    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-

  20. TRESS: A Transportable Radioactive Effluent Solidification System

    SciTech Connect

    Sims, J. [BBN Environmental Management Ltd., Bramhall (United Kingdom). WasteChem Div.; Schneider, K. [NUKEM GmbH, Alzenau (Germany)

    1993-12-31

    This paper describes an attempt to produce a totally new concept for a transportable plant capable of encapsulating radioactive sludges and ion exchange resins, employing recently developed dewatering and mixing techniques. One of the prime aims of the investigation was to produce a plant which could handle both beta/gamma and alpha-bearing materials.

  1. Obtaining and Investigating Unconventional Sources of Radioactivity

    ERIC Educational Resources Information Center

    Lapp, David R.

    2010-01-01

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

  2. 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...

  3. Annual Radioactive Waste Tank Inspection Program 1994

    SciTech Connect

    McNatt, F.G. Sr.

    1995-04-01

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

  4. Radiation Awareness TrainingRadiation Awareness Training Radioactive Material &Radioactive Material &

    E-print Network

    Sherrill, David

    quarterly · Radioactive waste retrieval, storage, disposal · Dosimetry exchange · Leak tests of sealed) · Sealed sources ­ Nickel-63 (Gas chromatograph) ­ Cesium-137 (Liquid Scintillation Counter) ­ Neutron

  5. Radiation safety of sealed radioactive sources.

    PubMed

    Pryor, Kathryn H

    2015-02-01

    Sealed radioactive sources are used in a wide variety of occupational settings and under differing regulatory/licensing structures. The definition of a sealed radioactive source varies between U.S. regulatory authorities and standard-setting organizations. Potential problems with sealed sources cover a range of risks and impacts. The loss of control of high activity sealed sources can result in very high or even fatal doses to members of the public who come in contact with them. Sources that are not adequately sealed and that fail can cause spread of contamination and potential intake of radioactive material. There is also the possibility that sealed sources may be (or threaten to be) used for terrorist purposes and disruptive opportunities. Until fairly recently, generally licensed sealed sources and devices received little, if any, regulatory oversight and were often forgotten, lost or unaccounted for. Nonetheless, generally licensed devices can contain fairly significant quantities of radioactive material, and there is some potential for exposure if a device is treated in a way for which it was never designed. Industrial radiographers use and handle high activity and/or high dose-rate sealed sources in the field with a high degree of independence and minimal regulatory oversight. Failure to follow operational procedures and properly handle radiography sources can and has resulted in serious injuries and death. Industrial radiographers have experienced a disproportionately large fraction of incidents that have resulted in unintended exposure to radiation. Sources do not have to contain significant quantities of radioactive material to cause problems in the event of their failure. A loss of integrity can cause the spread of contamination and potential exposure to workers and members of the public. The National Council on Radiation Protection and Measurements has previously provided recommendations on select aspects of sealed source programs. Future efforts to provide recommendations for sealed source programs are discussed. PMID:25551499

  6. Radioactive Waste Management in Central Asia - 12034

    SciTech Connect

    Zhunussova, Tamara; Sneve, Malgorzata; Liland, Astrid [Norwegian Radiation Protection Authority (Norway)

    2012-07-01

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

  7. 10 CFR 32.72 - Manufacture, preparation, or transfer for commercial distribution of radioactive drugs containing...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...abbreviation; and the quantity of radioactivity at a specified date and time. For...use instrumentation to measure the radioactivity of radioactive drugs. The licensee...measurements and calculations, the amount of radioactivity in dosages of alpha-, beta-,...

  8. 10 CFR 61.41 - Protection of the general population from releases of radioactivity.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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...

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

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...shall be posted at each very high radiation area. (d) Airborne radioactivity area. The words “Caution, Airborne Radioactivity Area” or “Danger, Airborne Radioactivity Area” shall be posted at each airborne radioactivity area....

  10. 10 CFR 32.72 - Manufacture, preparation, or transfer for commercial distribution of radioactive drugs containing...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...abbreviation; and the quantity of radioactivity at a specified date and time. For...use instrumentation to measure the radioactivity of radioactive drugs. The licensee...measurements and calculations, the amount of radioactivity in dosages of alpha-, beta-,...

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

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...shall be posted at each very high radiation area. (d) Airborne radioactivity area. The words “Caution, Airborne Radioactivity Area” or “Danger, Airborne Radioactivity Area” shall be posted at each airborne radioactivity area....

  12. 10 CFR 61.41 - Protection of the general population from releases of radioactivity.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...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...

  13. 10 CFR 32.72 - Manufacture, preparation, or transfer for commercial distribution of radioactive drugs containing...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...abbreviation; and the quantity of radioactivity at a specified date and time. For...use instrumentation to measure the radioactivity of radioactive drugs. The licensee...measurements and calculations, the amount of radioactivity in dosages of alpha-, beta-,...

  14. 10 CFR 32.72 - Manufacture, preparation, or transfer for commercial distribution of radioactive drugs containing...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...abbreviation; and the quantity of radioactivity at a specified date and time. For...use instrumentation to measure the radioactivity of radioactive drugs. The licensee...measurements and calculations, the amount of radioactivity in dosages of alpha-, beta-,...

  15. 10 CFR 835.603 - Radiological areas and radioactive material areas.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...shall be posted at each very high radiation area. (d) Airborne radioactivity area. The words “Caution, Airborne Radioactivity Area” or “Danger, Airborne Radioactivity Area” shall be posted at each airborne radioactivity area....

  16. 10 CFR 32.72 - Manufacture, preparation, or transfer for commercial distribution of radioactive drugs containing...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...abbreviation; and the quantity of radioactivity at a specified date and time. For...use instrumentation to measure the radioactivity of radioactive drugs. The licensee...measurements and calculations, the amount of radioactivity in dosages of alpha-, beta-,...

  17. 10 CFR 835.603 - Radiological areas and radioactive material areas.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...shall be posted at each very high radiation area. (d) Airborne radioactivity area. The words “Caution, Airborne Radioactivity Area” or “Danger, Airborne Radioactivity Area” shall be posted at each airborne radioactivity area....

  18. 10 CFR 61.41 - Protection of the general population from releases of radioactivity.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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...

  19. 10 CFR 61.41 - Protection of the general population from releases of radioactivity.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...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...

  20. 10 CFR 61.41 - Protection of the general population from releases of radioactivity.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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...

  1. 10 CFR 835.603 - Radiological areas and radioactive material areas.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...shall be posted at each very high radiation area. (d) Airborne radioactivity area. The words “Caution, Airborne Radioactivity Area” or “Danger, Airborne Radioactivity Area” shall be posted at each airborne radioactivity area....

  2. MANAGEMENT OF SOLID RADIOACTIVE WASTE Revised August 2008

    E-print Network

    Davidson, Fordyce A.

    k MANAGEMENT OF SOLID RADIOACTIVE WASTE Revised August 2008 Safety Services #12;MANAGEMENT OF SOLID for Appendices 4 and 5 22 Appendix 10 Flow chart of waste-streaming 23 #12;1 MANAGEMENT OF SOLID RADIOACTIVE RADIOACTIVE WASTES Page Minimisation 1 Streaming 2 Procedures 2 Keeping track of the activities placed

  3. Radioactive waste disposal in simulated peat bog repositories

    Microsoft Academic Search

    W. R. Schell; C. D. Massey

    1987-01-01

    The Low Level Radioactive Waste Policy Act of 1980 and the Low Level Radioactive Waste Policy Amendments Act of 1985 have required state governments to be responsible for providing low-level waste (LLW) disposal facilities in their respective areas. Questions are (a) is the technology sufficiently advanced to ensure that radioactive wastes can be stored for 300 to 1000 yr without

  4. 40 CFR 227.30 - High-level radioactive waste.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2011-07-01 true High-level radioactive waste. 227.30 Section 227.30 Protection... Definitions § 227.30 High-level radioactive waste. High-level radioactive waste means the aqueous waste resulting...

  5. 1 INSTRODUCTION In the concept of geological radioactive waste disposal,

    E-print Network

    Boyer, Edmond

    1 INSTRODUCTION In the concept of geological radioactive waste disposal, argillite is being of the radioactive waste disposal, the host rock will be subjected to various thermo-hydro-mechanical loadings, thermal solicitation comes from the heat emitting from the radioactive waste packages. On one hand

  6. ION-EXCHANGE PROCESSES FOR REMOVING RADIOACTIVE CONTAMINATION FROM MILK

    Microsoft Academic Search

    L. E. Edmondson

    1964-01-01

    SUMMARY These studies on removing radioactive contamination from milk were carried on for the purpose of developing a feasible standby process for use in dairy plants in the event that radioactive fallout should reach hazardous levels. Current levels of all the radioactive contaminants are far below what is con- sidered hazardous levels; Iodine-131 is essentially undetectable in all milk supplies.

  7. Ris-R-1549(EN) Thule-2003 -Investigation of Radioactive

    E-print Network

    Risø-R-1549(EN) Thule-2003 - Investigation of Radioactive Contamination Sven P. Nielsen and Per: Thule-2003 ­ Investigation of Radioactive Contamination Department: Radiation Research Risø-R-1549(EN if radioactive particles are resuspended in the air so that they might be inhaled. Risø National Laboratory

  8. Radioactive waste management in developing and newly industrialized countries

    Microsoft Academic Search

    A. S. Paschoa; A. Tranjan Filho

    1995-01-01

    Radioactive wastes are mostly produced in countries with military nuclear programmes. However, non-nuclear weapon countries, with solely commercial nuclear industries, also produce radioactive wastes. Moreover, uranium and thorium mining and milling wastes, as well as other kinds of low-level radioactive wastes like those resulting from radiological accidents, can also be found in developing and newly industrialized countries. The paper discusses

  9. An overview of military radioactive waste management in the UK

    Microsoft Academic Search

    Frederic Dawson

    1997-01-01

    The present and past activities of Ministry of Defence (MOD) have resulted in the production of radioactive waste, particularly from the naval nuclear propulsion programme and the nuclear weapons programme. The MOD manages radioactive waste in accordance with national policy and regulation, making use of disposal options where available. MOD radioactive waste management practices are subject to independent review and

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

    NASA Technical Reports Server (NTRS)

    Sinclair, W. K.

    1967-01-01

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

  11. Collation and presentation of radioactivity trend data from MAFF monitoring

    E-print Network

    Collation and presentation of radioactivity trend data from MAFF monitoring programmes from 1994-1998 2005 #12;Environment Report RL 4/05 Collation and presentation of radioactivity trend data from MAFF of Agriculture, Fisheries and Food operated a nationwide monitoring programme for radioactivity. At that time

  12. B-1 2003 SITE ENVIRONMENTAL REPORT Concepts of Radioactivity

    E-print Network

    Homes, Christopher C.

    B-1 2003 SITE ENVIRONMENTAL REPORT APPENDIX B Concepts of Radioactivity This section introduces some of the basic concepts of radioactivity to provide the general reader with a basic understanding here, inAppendix B, are discussions of the analyses used to quantify radioactive material, the common

  13. Die ^ o o \\3,S* Environmental Radioactivity in

    E-print Network

    Die ^ o o \\3,S* Risø-R-448 Environmental Radioactivity in the Faroes in 1980 A. Aarkrog, J. Lippert ENVIRONMENTAL RADIOACTIVITY IN THE FAROES IN 1980 A. Aarkrog, J. Lippert, and H. Dahlgaard Abstract. Measurements of fallout radioactivity in the Faroes in 1980 are presented. Strontium-90 (and 137cs in most

  14. Radioactive Needlework Reconstruction of needle-positions in radiation treatment

    E-print Network

    Hochstenbach, Michiel

    Radioactive Needlework Reconstruction of needle-positions in radiation treatment Claude Archer1 University, 5: Universiteit Leiden 103 #12;104 Radioactive Needlework Figure 5.1: Position of the device in the desired positions. The radioactive decay of the used iodine or palladium seeds is such that in half a year

  15. RadioActive: Enabling Persistent Mobile Communications for Groups

    E-print Network

    1 RadioActive: Enabling Persistent Mobile Communications for Groups Abstract Current mobile takes the first step in this direction by creating and evaluating an initial design called RadioActive. RadioActive is a technological and interaction design for persistent mobile audio chat spaces. Our work

  16. ^ a Ris-R-622(EN) Environmental Radioactivity

    E-print Network

    ^ a Risø-R-622(EN) Environmental Radioactivity in the North Atlantic Region Includingthe Faroe #12;Environmental Radioactivity ^-^mm in the North Atlantic Region Including the Faroe Islands National Laboratory, Roskilde, Denmark January 1994 #12;Abstract Measurements of fallout radioactivity

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

    Microsoft Academic Search

    Usher

    2007-01-01

    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

  18. s.haszeldine@ed.ac.uk Radioactive waste Cumbria: Maryport, Silloth 21, 22 Nov 2012 1 Geological disposal of radioactive

    E-print Network

    s.haszeldine@ed.ac.uk Radioactive waste Cumbria: Maryport, Silloth 21, 22 Nov 2012 1 Geological disposal of radioactive waste in Cumbria http://www.geos.ed.ac.uk/homes/rsh/MRWS_2012.html Stuart/rsh/ Allerdale_and_Copeland.html #12;Nuclear power s.haszeldine@ed.ac.uk Radioactive waste Cumbria: Maryport

  19. Handbook of high-level radioactive waste transportation

    SciTech Connect

    Sattler, L.R.

    1992-10-01

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

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

    SciTech Connect

    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

    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)

  1. Radioactive hot cell access hole decontamination machine

    DOEpatents

    Simpson, William E. (Richland, WA)

    1982-01-01

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

  2. Radioactive scrap metal decontamination technology assessment report

    SciTech Connect

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

    1996-04-01

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

  3. Various cluster radioactivities above magic nuclei

    E-print Network

    F. R. Xu; J. C. Pei

    2006-03-27

    We present parameter-free tunneling calculations for various cluster radioactivities including the diproton decays of atomic nuclei. An uniform folded cluster potential has been suggested that is based on a self-consistent mean-field model, with the folding factor determined using the quantization conditions of the quasibound cluster state. We have investigated the $\\alpha$-particle and heavier-cluster decays of trans-$^{100}$Sn and trans-$^{208}$Pb nuclei, and the observed diproton emission from the proton drip-line nucleus $^{16}$Ne, showing the overall reasonable descriptions of cluster radioactivities with calculated half-lives agreeing well with experimental data. We have also predicted the properties of yet unobserved cluster decays of the exotic nuclei $^{112,114}$Ba, $^{104}$Te and $^{38}$Ti.

  4. Two-proton radioactivity of 45Fe

    SciTech Connect

    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

    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.

  5. Solar Powered Radioactive Air Monitoring Stations

    SciTech Connect

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

    2013-10-30

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

  6. Comparative alkali washing of simulated radioactive sludge

    SciTech Connect

    Fugate, G.A.; Ensor, D.D. [Tennessee Technological Univ., Cookeville, TN (United States); Egan, B.Z. [Oak Ridge National Lab., TN (United States)

    1996-10-01

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

  7. Airborne radioactivity surveys for phosphate in Florida

    USGS Publications Warehouse

    Moxham, Robert M.

    1953-01-01

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

  8. Proton radioactivity with a Yukawa effective interaction

    E-print Network

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

    2011-04-26

    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.

  9. Airborne radioactivity surveys for phosphate in Florida

    USGS Publications Warehouse

    Moxham, Robert M.

    1954-01-01

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

  10. Detection of radioactive accumulations within an incinerator

    SciTech Connect

    Schoenig, F.C. Jr.; Grossman, L.N.

    1986-03-25

    This patent describes an incinerator for burning combustible material contaminated by radiation. This incinerator has a combustion chamber having containment walls of high density refractory brick provided with at least one window opening through the high density refractory brick containment walls. The window consists of a low density body of ceramic fibers. Any radiation from residual radioactive ash within the incinerator containment and inhibited by the high density refractory brick can penetrate outward through the window of low density fiber to beyond the incinerator containment walls. A radiation detector is mounted outside the incinerator containment walls adjacent to the window of low density ceramic fiber for measuring any radiation passing out from the combustion chamber through the low density window. The amount of retained radioactive ash accumulated in the incinerator combustion chamber is indicated on the detector.

  11. Transport of Carbon Dioxide and Radioactive Waste

    Microsoft Academic Search

    Darío R. Gómez; Michael Tyacke

    \\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

  12. Radioactive contamination of the Yenisei River

    Microsoft Academic Search

    E. G. Tertyshnik

    1995-01-01

    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

  13. Performance assessment of radioactive waste repositories

    Microsoft Academic Search

    J. E. Campbell; R. M. Cranwell

    1988-01-01

    The current plans for permanent disposal of radioactive waste call for its emplacement in deep underground repositories mined from geologically stable rock formations. The U.S. Nuclear Regulatory Commission and U.S. Environmental Protection Agency have established regulations setting repository performance standards for periods of up to 10,000 years after disposal. Compliance with these regulations will be based on a performance assessment

  14. Radioactive beams with the HHIRF accelerators

    Microsoft Academic Search

    D. K. Olsen; G. D. Alton; C. Baktash; H. K. Carter; D. T. Dowling; J. D. Garrett; D. L. Haynes; C. M. Jones; R. C. Juras; I. Y. Lee; M. J. Meigs; G. D. Mills; S. W. Mosko; B. A. Tatum; K. S. Toth

    1991-01-01

    It is pointed out that the two accelerators of the Holifield Heavy Ion Research Facility (HHIRF) provide a unique opportunity to quickly and economically develop an interim proton-rich, medium-intensity, ISOL-type, RIB (radioactive ion beam) facility. This extension of the HHIRF would provide for research and development until the much larger facility can be realized in the late 1990s. Presently, the

  15. Discovery of oxygen radioactivity of atomic nuclei

    Microsoft Academic Search

    R. Bonetti; C. Chiesa; A. Guglielmetti; C. Migliorino; A. Cesana; M. Terrani

    1993-01-01

    By using solid-state nuclear track detectors arranged in 2pi geometry we collected 27 events due to the radioactive decay of 228Th by 20O emission. The partial half-life is (5.29 +\\/- 1.01) × 1020 s and the branching ratio relative to alpha decay is (1.13 +\\/- 0.22) × 10-13. This is the first case of observation of spontaneous emission of oxygen

  16. Progress of radioactive waste management in Korea

    Microsoft Academic Search

    Y. S. Hwang; C. H. Kang; S. G. Kim; H. S. Park

    2003-01-01

    In Korea, sixteen nuclear reactors are in operation and by 2015, there will be a total of twenty-six nuclear reactors. The current generating capacity is 12,990 MWe with a share of 40.7 % of the total production of electricity. This active nuclear program causes an inevitable increase in the build-up of radioactive waste, including spent fuel. Therefore, reliable and effective

  17. Progress of radioactive waste management in Lithuania

    Microsoft Academic Search

    P. Poskas; J. E. Adomaitis; V. Ragaisis; V. Simonis; A. Smaizys; R. Kilda; D. Grigaliuniene

    The only one nuclear power plant in the Republic of Lithuania – Ignalina Nuclear Power Plant contains two RBMK-1500 water-cooled graphite-moderated channel-type power reactors. The first and the second reactors were shut down by the end of 2004 and by the end of 2009, respectively. During operation, the power plant has accumulated large quantities of radioactive waste, including spent nuclear

  18. Electrically Driven Technologies for Radioactive Aerosol Abatement

    SciTech Connect

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

    2003-01-28

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

  19. Novel techniques to search for neutron radioactivity

    E-print Network

    M. Thoennessen; G. Christian; Z. Kohley; T. Baumann; M. Jones; J. K. Smith; J. Snyder; A. Spyrou

    2013-07-08

    Two new methods to observe neutron radioactivity are presented. Both methods rely on the production and decay of the parent nucleus in flight. The relative velocity measured between the neutron and the fragment is sensitive to half-lives between ~1 and ~100 ps for the Decay in Target (DiT) method. The transverse position measurement of the neutron in the Decay in a Magnetic Field (DiMF) method is sensitive to half-lives between 10 ps and 1 ns.

  20. A Simple Example of Radioactive Dating

    ERIC Educational Resources Information Center

    Brown, Todd

    2014-01-01

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

  1. Soils: man-caused radioactivity and radiation forecast

    SciTech Connect

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

    2007-07-01

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

  2. Molecular Optical Imaging with Radioactive Probes

    PubMed Central

    Liu, Hongguang; Ren, Gang; Miao, Zheng; Zhang, Xiaofen; Tang, Xiaodong; Han, Peizhen; Gambhir, Sanjiv S.; Cheng, Zhen

    2010-01-01

    Background Optical imaging (OI) techniques such as bioluminescence and fluorescence imaging have been widely used to track diseases in a non-invasive manner within living subjects. These techniques generally require bioluminescent and fluorescent probes. Here we demonstrate the feasibility of using radioactive probes for in vivo molecular OI. Methodology/Principal Findings By taking the advantages of low energy window of light (1.2–3.1 eV, 400–1000 nm) resulting from radiation, radionuclides that emit charged particles such as ?+ and ?? can be successfully imaged with an OI instrument. In vivo optical images can be obtained for several radioactive probes including 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG), Na18F, Na131I, 90YCl3 and a 90Y labeled peptide that specifically target tumors. Conclusions/Significance These studies demonstrate generalizability of radioactive OI technique. It provides a new molecular imaging strategy and will likely have significant impact on both small animal and clinical imaging. PMID:20208993

  3. Radioactive Waste Burial Grounds. Environmental Information Document

    SciTech Connect

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

    1987-03-01

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

  4. Future radioactive liquid waste streams study

    SciTech Connect

    Rey, A.S.

    1993-11-01

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

  5. Integration of Radioactive Material with Microcalorimeter Detectors

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  6. Sources of Radioactive Isotopes for Dirty Bombs

    NASA Astrophysics Data System (ADS)

    Lubenau, Joel

    2004-05-01

    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.

  7. Economic feasibility of recycling radioactive scrap steel

    SciTech Connect

    Balhiser, B.C.; Rosholt, D.L. [MSE, Inc., Butte, MT (United States); Nichols, F.A. [Manufacturing Sciences Corp., Oak Ridge, TN (United States)

    1995-12-31

    Radioactive scrap metal has traditionally been disposed of by burial in low-level waste repositories, an option that will become increasingly unattractive if burial costs rise as projected. This paper will examine recycling opportunities that may arise from two divergent economic trends: (1) escalating burial costs, and (2) historically flat product costs from state-of-the-art metal recycle operations. Emphasis will be placed on recycling the radioactive scrap steel (RSS) that will arise from D&D of Government and commercial nuclear facilities in the western United States. An effort is underway to compare processes for recycling RSS at least cost to the generator, least impact to the environment, and minimum worker exposure to radionuclide hazards. An experienced industry team with expertise in radioactive metals recycling, commercial steel recycling, and state-of-the-art metal recycle facilities design has been assembled under subcontract for this purpose. Methods for evaluating process options to arrive at an optimized solution will be discussed in the paper. An analysis of burial versus recycle costs for RSS will also be presented.

  8. Geological problems in radioactive waste isolation

    SciTech Connect

    Witherspoon, P.A. (ed.)

    1991-01-01

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

  9. Scrap metals industry perspective on radioactive materials.

    PubMed

    Turner, Ray

    2006-11-01

    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

  10. Radioactive waste management in the former USSR

    SciTech Connect

    Bradley, D.J.

    1992-06-01

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

  11. RESRAD. Site-Specific Residual Radioactivity

    SciTech Connect

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

    1989-06-01

    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.

  12. Radioactive iodine therapy in cats with hyperthyroidism

    SciTech Connect

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

    1984-03-01

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

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

    SciTech Connect

    Fischer, D.K.; Gitt, M.; Williams, G.A.; Branch, S. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Otis, M.D.; McKenzie-Carter, M.A.; Schurman, D.L. (Science Applications International Corp., Idaho Falls, ID (United States))

    1991-07-01

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

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

    SciTech Connect

    Fischer, D.K.; Gitt, M.; Williams, G.A.; Branch, S. [EG and G Idaho, Inc., Idaho Falls, ID (United States); Otis, M.D.; McKenzie-Carter, M.A.; Schurman, D.L. [Science Applications International Corp., Idaho Falls, ID (United States)

    1991-07-01

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

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

    PubMed

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

    2014-12-01

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

  16. Upgrading the Radioactive Waste Management Infrastructure in Azerbaijan

    SciTech Connect

    Huseynov, A. [Baku Radioactive Waste Site IZOTOP, Baku (Azerbaijan); Batyukhnova, O. [State Unitary Enterprise Scientific and Industrial Association Radon, Moscow (Russian Federation); Ojovan, M. [Sheffield Univ., Immobilisation Science Lab. (United Kingdom); Rowat, J. [International Atomic Energy Agency, Dept. of Nuclear Safety and Security, Vienna (Austria)

    2007-07-01

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

  17. Time-dependent radioactivity distribution in MAFF

    NASA Astrophysics Data System (ADS)

    Nebel, F.; Zech, E.; Faestermann, T.; Krücken, R.; Maier-Komor, P.; Assmann, W.; Szerypo, J.; Groß, M.; Kester, O.; Thirolf, P. G.; Grötzschel, R.

    2006-05-01

    The Munich Accelerator for Fission Fragments is planned to be installed at the FRM II in Garching. It will operate a uranium-carbide-loaded graphite matrix as a target for neutron-induced fission. The radioactive reaction fragments leave the ion source as both, atoms and ions. For radiation safety it is imperative to have a basic understanding of the fragment distribution within the beam line. Atoms leaving the graphite matrix will spread like a gas and stick to surfaces depending on their species. A probabilistic Monte-Carlo approach is used to predict the surface coating of internal surfaces of the beam line for all fission nuclides. To decrease calculation time, the problem is reduced to two dimensions with the surface areas being a measure for the probability, that they are hit by a particle. The program is completely time dependent to implement radioactive decay. Ions leaving the fission ion source are transported by electrostatic means towards the mass pre-separator, a low-resolution dipole magnet with a complex slit system in the focal plane. All unwanted ions are stopped at the slits, resulting in a high level of radioactive contamination. While it is advantageous for shielding purposes to have the majority of the contamination in one point, precautions must be taken to ensure that it stays that way. Material corrosion caused by sputtering will release previously implanted radionuclides. To reduce this effect, different methods are under investigation, one of which is changing the slit geometry. The considered designs will be described and experimental results will be shown.

  18. Environmental Assessment Radioactive Source Recovery Program

    SciTech Connect

    NONE

    1995-12-20

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

  19. RECLAMATION OF RADIOACTIVE MATERIAL PACKAGING COMPONENTS

    SciTech Connect

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

    2011-06-06

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

  20. Corrosion resistant storage container for radioactive material

    DOEpatents

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

    1984-08-30

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

  1. System for handling and storing radioactive waste

    DOEpatents

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

    1982-07-19

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

  2. Hanford Site radioactive hazardous materials packaging directory

    SciTech Connect

    McCarthy, T.L.

    1995-12-01

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

  3. Particle beam generator using a radioactive source

    DOEpatents

    Underwood, David G. (Naperville, IL)

    1993-01-01

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

  4. Residual radioactive material guidelines: Methodology and applications

    SciTech Connect

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

    1989-01-01

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

  5. Measurements of natural radioactivity inside dandara temple

    NASA Astrophysics Data System (ADS)

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

    1994-07-01

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

  6. Radioactive waste disposal via electric propulsion

    NASA Technical Reports Server (NTRS)

    Burns, R. E.

    1975-01-01

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

  7. Biosphere modelling for radioactive waste disposal

    SciTech Connect

    Klos, R.A. [Paul Scherrer Institute, Wuerenlingen (Switzerland); Van Dorp, F. [NAGRA, Wettingen (Switzerland)

    1996-12-01

    Swiss radiological protection regulations specify dose and risk limits for radioactive waste disposal. Biosphere modelling is used to estimate doses to inhabitants of the potentially affected region. No time limit is specified and for biosphere modelling in the far future a reference biospheres approach is recommended. Predictions of future exposures are not made, but representative scenarios based on present day analogues are used to show that the potential radionuclide releases would not breach regulatory limits under these reference conditions. Probabilistic modelling may form part of the assessment but is not a formal requirement.

  8. System for handling and storing radioactive waste

    DOEpatents

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

    1984-01-01

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

  9. Heavy particle radioactivities of superheavy nuclei

    E-print Network

    D. N. Poenaru; R. A. Gherghescu; W. Greiner

    2011-08-13

    The concept of heavy particle radioactivity (HPR) is changed to allow emitted particles with Z_e>28 from parents with Z>110 and daughter around 208Pb. Calculations for superheavy (SH) nuclei with Z=104-124 are showing a trend toward shorter half-lives and larger branching ratio relative to alpha decay for heavier SHs. It is possible to find regions in which HPR is stronger than alpha decay. The new mass table AME11 and the theoretical KTUY05 and FRDM95 masses are used to determine the released energy. For 124 we found isotopes with half-lives in the range of ns to ps.

  10. Electronic Denitration Savannah River Site Radioactive Waste

    SciTech Connect

    Hobbs, D.T.

    1995-04-11

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

  11. Economic feasibility of radioactive scrap steel recycling

    SciTech Connect

    Balhiser, R.; Rosholt, D. [MSE, Inc., Butte, MT (United States); Nichols, F. [Manufacturing Sciences Corporation, Woodland, WA (United States)

    1995-12-31

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

  12. Reusing nylon membranes for radioactive hybridizations.

    PubMed

    Thornbury, D W; Farman, M L

    2000-12-01

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

  13. Astrophysics experiments with radioactive beams at ATLAS

    SciTech Connect

    Back, B. B.; Clark, J. A.; Pardo, R. C.; Rehm, K. E., E-mail: rehm@anl.gov; Savard, G. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States)] [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2014-04-15

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

  14. Introduction to naturally occurring radioactive material

    SciTech Connect

    Egidi, P.

    1997-08-01

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

  15. World new facilities for radioactive isotope beams

    NASA Astrophysics Data System (ADS)

    Motobayashi, Tohru

    2014-03-01

    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.

  16. Radioactive nuclides as tracers of environmental processes

    Microsoft Academic Search

    C. Papastefanou

    2006-01-01

    Summary  Relatively short-lived radioactive nuclides of cosmogenic origin, such as7Be (T1\\/2=53.3 d),32P (14.3 d),33P (25.3 d),35S (87.4 d) as well as22Na (2.6 y) have come to be recognized as potential tools to trace environmental processes, such as precipitation, washout\\u000a (precipitation scavenging), resuspension, atmospheric particle deposition and deposition patterns of airborne contaminants,\\u000a aerosol deposition and aerosol trapping by above ground vegetation (air-to-vegetation

  17. Corrosion resistant storage container for radioactive material

    DOEpatents

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

    1990-01-01

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

  18. Proton radioactivity half lives with Skyrme interactions

    E-print Network

    T. R. Routray; Abhishek Mishra; S. K. Tripathy; B. Behera; D. N. Basu

    2012-05-31

    The potential barrier impeding the spontaneous emission of protons in the proton radioactive nuclei is calculated as the sum of nuclear, Coulomb and centrifugal contributions. The nuclear part of the proton-nucleus interaction potential is obtained in the energy density formalism using Skyrme effective interaction that results into a simple algebraic expression. The half-lives of the proton emitters are calculated for the different Skyrme sets within the improved WKB framework. The results are found to be in reasonable agreement with the earlier results obtained for more complicated calculations involving finite range interactions.

  19. Some Perspectives on Future Proton Radioactivity Experiments

    SciTech Connect

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

    2011-11-30

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

  20. Particle beam generator using a radioactive source

    DOEpatents

    Underwood, D.G.

    1993-03-30

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

  1. Hazardous and radioactive waste incineration studies

    SciTech Connect

    Vavruska, J.S.; Stretz, L.A.; Borduin, L.C.

    1981-01-01

    Development and demonstration of a transuranic (TRU) waste volume-reduction process is described. A production-scale controlled air incinerator using commercially available equipment and technology has been modified for solid radioactive waste service. This unit successfully demonstrated the volume reduction of transuranic (TRU) waste with an average TRU content of about 20 nCi/g. The same incinerator and offgas treatment system is being modified further to evaluate the destruction of hazardous liquid wastes such as polychlorinated biphenyls (PCBs) and hazardous solid wastes such as pentachlorophenol (PCP)-treated wood.

  2. Conversion of radioactive tryptophan to indoleacetic acid by plant tissues

    E-print Network

    Dannenburg, Warren Nathaniel

    1957-01-01

    on the chromatograms was accomplished bj the use of ultraviolet light, radioactivity measurements, and color reactions with chemical reagents* Detection by ultra? violet light and by radioactivity are discussed below, while a discussion of the chemical reactions...) and more recently with ultraviolet light using metabolic pro? ducts of naphthalene ($)? It is apparent that this means of quantification can be applied to indole compounds as illustrated in Table k using indoleacetic acid. Radioactivity measurements...

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

    ERIC Educational Resources Information Center

    Klein, Lynda; Kagan, David

    2010-01-01

    The idea of using a dice game to simulate radioactive decay is not new. However, modern pedagogy encourages, if not requires, us to provide multiple representations and visualizations for our students. The advantage of interactive engagement methods also has been made clear. Here we describe a highly visual and interactive use of dice to develop…

  4. Karlsruhe Database for Radioactive Wastes (KADABRA) - Accounting and Management System for Radioactive Waste Treatment - 12275

    SciTech Connect

    Himmerkus, Felix; Rittmeyer, Cornelia [WAK Rueckbau- und Entsorgungs- GmbH, 76339 Eggenstein-Leopoldshafen (Germany)

    2012-07-01

    The data management system KADABRA was designed according to the purposes of the Cen-tral Decontamination Department (HDB) of the Wiederaufarbeitungsanlage Karlsruhe Rueckbau- und Entsorgungs-GmbH (WAK GmbH), which is specialized in the treatment and conditioning of radioactive waste. The layout considers the major treatment processes of the HDB as well as regulatory and legal requirements. KADABRA is designed as an SAG ADABAS application on IBM system Z mainframe. The main function of the system is the data management of all processes related to treatment, transfer and storage of radioactive material within HDB. KADABRA records the relevant data concerning radioactive residues, interim products and waste products as well as the production parameters relevant for final disposal. Analytical data from the laboratory and non destructive assay systems, that describe the chemical and radiological properties of residues, production batches, interim products as well as final waste products, can be linked to the respective dataset for documentation and declaration. The system enables the operator to trace the radioactive material through processing and storage. Information on the actual sta-tus of the material as well as radiological data and storage position can be gained immediately on request. A variety of programs accessed to the database allow the generation of individual reports on periodic or special request. KADABRA offers a high security standard and is constantly adapted to the recent requirements of the organization. (authors)

  5. Journal of Environmental Radioactivity special issue: international topical conference on Po and radioactive Pb isotopes.

    PubMed

    Holm, Elis; Garcia-Tenorio, Rafael

    2011-05-01

    An international conference on polonium (Po) and radioactive isotopes was held in Seville Spain, 26-28 October 2009 at the Centro Nacional de Aceleradores. It was attended by 138 participants from 38 different countries. The sessions covered all aspects on Po and lead (Pb) such as radiochemistry, terrestrial and marine radioecology, kinetics, sedimentation rates, atmospheric tracers, NORM industries and dose assessment. PMID:20889244

  6. Titanate-based adsorbents for radioactive ions entrapment from water.

    PubMed

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

    2013-03-21

    This feature article reviews some titanate-based adsorbents for the removal of radioactive wastes (cations and anions) from water. At the beginning, we discuss the development of the conventional ion-exchangeable titanate powders for the entrapment of radioactive cations, such as crystalline silicotitanate (CST), monosodium titanate (MST), peroxotitanate (PT). Then, we specially emphasize the recent progress in the uptake of radioactive ions by one-dimensional (1D) sodium titanate nanofibers and nanotubes, which includes the synthesis and phase transformation of the 1D nanomaterials, adsorption ability (capacity, selectivity, kinetics, etc.) of radioactive cations and anions, and the structural evolution during the adsorption process. PMID:23412572

  7. Radioactive Ion Beam Production Capabilities At The Holifield Radioactive Ion Beam Facility

    SciTech Connect

    Beene, J. R.; Dowling, D. T.; Gross, C. J.; Juras, R. C.; Liu, Y.; Meigs, M. J.; Mendez, A. J. II; Nazarewicz, W.; Sinclair, J. W.; Stracener, D. W.; Tatum, B. A. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2011-06-01

    The Holifield Radioactive Ion Beam Facility (HRIBF) is a national user facility for research with radioactive ion beams (RIBs) that has been in routine operation since 1996. It is located at Oak Ridge National Laboratory (ORNL) and operated by the ORNL Physics Division. The principal mission of the HRIBF is the production of high quality beams of shortlived radioactive isotopes to support research in nuclear structure physics and nuclear astrophysics. HRIBF is currently unique worldwide in its ability to provide neutron-rich fission fragment beams post-accelerated to energies above the Coulomb barrier for nuclear reactions. HRIBF produces RIBs by the isotope separator on-line (ISOL) technique using a particle accelerator system that consists of the Oak Ridge Isochronous Cyclotron (ORIC) driver accelerator, one of the two Injectors for Radioactive Ion Species (IRIS1 or IRIS2) production systems, and the 25-MV tandem electrostatic accelerator that is used for RIB post-acceleration. ORIC provides a light ion beam (proton, deuteron, or alpha) which is directed onto a thick target mounted in a target-ion source (TIS) assembly located on IRIS1 or IRIS2. Radioactive atoms that diffuse from the target material are ionized, accelerated, mass selected, and transported to the tandem accelerator where they are further accelerated to energies suitable for nuclear physics research. RIBs are transported through a beam line system to various experimental end stations including the Recoil Mass Spectrometer (RMS) for nuclear structure research, and the Daresbury Recoil Separator (DRS) for nuclear astrophysics research. HRIBF also includes two off-line ion source test facilities, one low-power on-line ISOL test facility (OLTF), and one high-power on-line ISOL test facility (HPTL). This paper provides an overview and status update of HRIBF, describes the recently completed $4.7M IRIS2 addition and incorporation of laser systems for beam production and purification, and discusses a proposed replacement of the ORIC driver accelerator.

  8. Laser ion sources for radioactive beams (invited)

    SciTech Connect

    Lecesne, N. [Grand Accelerateur National d'Ions Lourds, BP 55027, 14076 Caen cedex 5 (France)

    2012-02-15

    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.

  9. 2p radioactivity studied by tracking technique

    NASA Astrophysics Data System (ADS)

    Mukha, Ivan

    2010-06-01

    The recent advance in experimental studies of short-lived exotic nuclei beyond the proton drip line is presented. In particular, in-flight decays of proton-unbound nuclei with picosecond lifetimes can be probed by a novel technique which tracks all decay products precisely, and the decay vertices as well as the angular correlations of the fragments are deduced from the measured trajectories. The corresponding pioneering experiment which identified a previously-unknown isotope 19Mg and its two-proton (2p) radioactivity as well as studied the reference 2p decay of the known isotope 16Ne is described. Systematic studies of other 2p precursors beyond the proton drip line are foreseen with this powerful technique whose sensitivity is larger by factor of 30 in comparison with a conventional invariant-mass method. The 2p radioactivity candidates 30Ar, 34Ca and 26S are discussed. Information about the respective one-proton unbound nuclei can be obtained with this technique by evaluating proton-heavy-fragment correlations. Systematic studies of nuclei beyond the proton drip line, e.g., the well-known proton resonances above the ``waiting points'' in the astrophysical rp-process, 69Br and 73Br are feasible.

  10. Resonant laser ionization of radioactive atoms*1

    NASA Astrophysics Data System (ADS)

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

    2003-06-01

    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.

  11. DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

    SciTech Connect

    NA

    2004-11-22

    The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) important to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are in the form of tabulated functions with pH and log (line integral) CO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. The output data from this report are fundamental inputs for Total System Performance Assessment for the License Application (TSPA-LA) to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for all of the actinides. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.

  12. Storage rings for radioactive ion beams

    NASA Astrophysics Data System (ADS)

    Nolden, F.; Dimopoulou, C.; Dolinskii, A.; Steck, M.

    2008-10-01

    Storage rings for radioactive heavy ions can be applied for a wide range of experiments in atomic and nuclear physics. The rare isotope beams are produced in flight via fragmentation or fission of high-intensity primary ions and they circulate in the storage ring at moderately relativistic energies (typically between 0.1 GeV/u up to 1 GeV/u). Due to their production mechanism they are usually highly charged or even fully stripped. The circulating radioactive heavy ion beams can be used to measure nuclear properties such as masses and decay times, which, in turn, can depend strongly on the ionic charge state. The storage rings must have large acceptances and dynamic apertures. The subsequent application of stochastic precooling of the secondary ions which are injected with large transverse and longitudinal emittances, and electron cooling to reach very high phase space densities has turned out to be a helpful tool for experiments with short-lived ions having lifetimes down to a few seconds. Some of these experiments have already been performed at the experimental storage ring ESR at GSI. The storage ring complex of the FAIR project is intended to enhance significantly the range of experimental possibilities. It is planned to extend the scope of experimental possibilities to collisions with electron or antiproton beams.

  13. 2p radioactivity studied by tracking technique

    SciTech Connect

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

    2010-06-01

    The recent advance in experimental studies of short-lived exotic nuclei beyond the proton drip line is presented. In particular, in-flight decays of proton-unbound nuclei with picosecond lifetimes can be probed by a novel technique which tracks all decay products precisely, and the decay vertices as well as the angular correlations of the fragments are deduced from the measured trajectories. The corresponding pioneering experiment which identified a previously-unknown isotope {sup 19}Mg and its two-proton (2p) radioactivity as well as studied the reference 2p decay of the known isotope {sup 16}Ne is described. Systematic studies of other 2p precursors beyond the proton drip line are foreseen with this powerful technique whose sensitivity is larger by factor of 30 in comparison with a conventional invariant-mass method. The 2p radioactivity candidates {sup 30}Ar, {sup 34}Ca and {sup 26}S are discussed. Information about the respective one-proton unbound nuclei can be obtained with this technique by evaluating proton-heavy-fragment correlations. Systematic studies of nuclei beyond the proton drip line, e.g., the well-known proton resonances above the 'waiting points' in the astrophysical rp-process, {sup 69}Br and {sup 73}Br are feasible.

  14. Marie Curie and the Science of Radioactivity

    NSDL National Science Digital Library

    2006-12-07

    This digital exhibit explores the life and accomplishments of Marie Curie, the Nobel-Prize winning physicist who discovered the radioactive elements polonium and radium. The exhibit integrates primary source lab notes, diary and journal entries, and historic photos to give a poignant view of Curie's struggles: growing up in the Russian-controlled Poland of the late 19th Century, being the target of repeated discrimination during her higher education in Paris, working with radioactive materials in substandard lab conditions, dealing with the consuming grief of her husband, Pierre's, accidental death in 1906, and overcoming challenges to win two Nobel Prizes. Editor's Note: It can be difficult for students to appreciate science as a human endeavor. This resource was designed to help learners grasp the hardships and obstacles often faced by pioneering scientists, especially women and minorities. Just as important, it gives them a glimpse at the joys of discovery. For a simulation on the same topic, see Related Materials: PhET Alpha Decay, which contains a very good accompanying lesson plan for high school teachers.

  15. Coulomb excitation of radioactive 20, 21Na

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    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 the Si detector BAMBINO. For 21Na , Coulomb excitation from the 3/2+ ground state to the first excited 5/2+ state was observed, while for 20Na , Coulomb excitation was observed from the 2+ ground state to the first excited 3+ and 4+ states. For both beams, B ( ? L) values were determined using the 2+ rightarrow 0+ de-excitation in 48Ti as a reference. The resulting B( E2) ? value for 21Na is 137±9 e^2fm^4, while the resulting B( ? L) ? values for 20Na are 55±6 e^2fm^4 for the 3+ rightarrow 2+ , 35.7±5.7 e^2 fm^4 for the 4+ rightarrow 2+ , and 0.154±0.030 ?_ N^2 for the 4+ rightarrow 3+ transitions. This analysis significantly improves the measurement of the 21Na B( E2) value, and provides the first experimental determination of B( ? L) values for the proton dripline nucleus 20Na .-1

  16. Radioactivities induced in some LDEF samples

    NASA Technical Reports Server (NTRS)

    Reedy, Robert C.; Moss, Calvin E.; Bobias, S. George; Masarik, Jozef

    1993-01-01

    Radioactivities induced in several Long Duration Exposure Facilities (LDEF) samples were measured by low-level counting at Los Alamos and elsewhere. These radionuclides have activities similar to those observed in meteorites and lunar samples. Some trends were observed in these measurements in terms of profiles in trunnion layers and as a function of radionuclide half-life. Several existing computer codes were used to model the production by the protons trapped in the Earth's radiation belts and by the galactic cosmic rays of some of these radionuclides, Mn-54 and Co-57 in steel, Sc-46 in titanium, and Na-22 in alloys of titanium and aluminum. Production rates were also calculated for radionuclides possibly implanted in LDEF, Be-7, Be-10, and C-14. Enhanced concentrations of induced isotopes in the surfaces of trunnion sections relative to their concentrations in the center are caused by the lower-energy protons in the trapped radiation. Secondary neutrons made by high-energy trapped protons and by galactic cosmic rays produce much of the observed radioactivities, especially deep in an object. Comparisons of the observed to calculated activities of several radionuclides with different half-lives indicate that the flux of trapped protons at LDEF decreased significantly at the end of the mission.

  17. Folding model analysis of alpha radioactivity

    E-print Network

    D. N. Basu

    2003-07-29

    Radioactive decay of nuclei via emission of $\\alpha$ particles has been studied theoretically in the framework of a superasymmetric fission model using the double folding (DF) procedure for obtaining the $\\alpha$-nucleus interaction potential. The DF nuclear potential has been obtained by folding in the density distribution functions of the $\\alpha$ nucleus and the daughter nucleus with a realistic effective interaction. The M3Y effective interaction has been used for calculating the nuclear interaction potential which has been supplemented by a zero-range pseudo-potential for exchange along with the density dependence. The nuclear microscopic $\\alpha$-nucleus potential thus obtained has been used along with the Coulomb interaction potential to calculate the action integral within the WKB approximation. This subsequently yields microscopic calculations for the half lives of $\\alpha$ decays of nuclei. The density dependence and the exchange effects have not been found to be very significant. These calculations provide reasonable estimates for the lifetimes of $\\alpha$ radioactivity of nuclei.

  18. The political science of radioactive waste disposal

    SciTech Connect

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

    1996-06-01

    This paper was first presented at the annual meeting of the HPS in New Orleans in 1984. Twelve years later, the basic lessons learned are still found to be valid. In 1984, the following things were found to be true: A government agency is preferred by the public over a private company to manage radioactive waste. Semantics are important--How you say it is important, but how it is heard is more important. Public information and public relations are very important, but they are the last thing of concern to a scientist. Political constituency is important. Don`t overlook the need for someone to be on your side. Don`t forget that the media is part of the political process-they can make you or break you. Peer technical review is important, but so is citizen review. Sociology is an important issue that scientists and technical people often overlook. In summary, despite the political nature of radioactive waste disposal, it is as true today as it was in 1984 that technical facts must be used to reach sound technical conclusions. Only then, separately and openly, should political factors be considered. So, what can be said today that wasn`t said in 1984? Nothing. {open_quotes}It`s deja vu all over again.{close_quotes}

  19. C-1 1999 SITE ENVIRONMENTAL REPORT APPENDIX C: CONCEPTS OF RADIOACTIVITY

    E-print Network

    C-1 1999 SITE ENVIRONMENTAL REPORT APPENDIX C: CONCEPTS OF RADIOACTIVITY APPENDIX C: Concepts of Radioactivity INTRODUCTION This section introduces some of the basic concepts of radioactivity. It is designed. A discussion of the analyses used to quantify radioactive material, the common sources of radioactivity

  20. B-1 2002 SITE ENVIRONMENTAL REPORT APPENDIX B: CONCEPTS OF RADIOACTIVITY

    E-print Network

    Homes, Christopher C.

    B-1 2002 SITE ENVIRONMENTAL REPORT APPENDIX B: CONCEPTS OF RADIOACTIVITY APPENDIX B Concepts of Radioactivity This section introduces some of the basic concepts of radioactivity. It is designed to provide.Adiscussion of the analyses used to qualitatively quantify radioactive material, the common sources of radioactivity