DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Data are summarized on fission-product activity during the period from October 1958 to October 1959. Measurements of airborne activity were made both above and below the tropopause layer. The effects were studied of heavy stratospheric injections from nuclear tests during 1958, after a year free from nuclear tests. lt was estimated that about 40 megatons of total fission energy was released during l958. About 20 megatons were released during the tests in the Arctic during September and October, 1958. The measured abundance of various nuclides indicates that the bulk of the heavy fall-out over Scandinavia was injected during October l958.more » Data are tabulated. (C.H.)« less

STRONTIUM 90: ESTIMATION OF WORLDWIDE DEPOSITION.

PubMed

VOLCHOK, H L

1964-09-25

The relation between the worldwide deposition of strontium-90, as calculated by many investigators over the last decade, and that observed in rainfall in New York City has been relatively constant. On the average, for each millicurie of strontium-90 per square mile deposited in New York City, 0.055 megacurie has been deposited on the earth's total surface. Cumulative deposits of strontium-90 on the earth's surface at various intervals over the last 10 years have been computed from this ratio. From the mean quarterly fraction of the annual strontium-90 fallout in New York City for the last 9 years, the worldwide deposition of this nuclide, equal to 2.48 megacuries, is predicted for 1964.

Fallout Radionuclides as Tracers in Southern Alps Sediment Studies

NASA Astrophysics Data System (ADS)

Carey, A. E.; Karanovic, Z.; Dibb, J. E.

2005-12-01

The primary geologic processes shaping the landscape are physical and chemical weathering and the transport of solids by erosion. As part of our studies on the coupling between physical erosion and chemical weathering, we have determined depositional and erosional processes in New Zealand's tectonically active, rapidly uplifting Southern Alps, specifically focusing on the Hokitika River watershed. The South Island watersheds we are studying are subject to extreme orographic precipitation (as high as 7-12 m annually) and high landslide frequency, but have modest topography due to the rapid erosion. In concert with our studies of chemical weathering and physical erosion, we have used the atmospherically-delivered radionuclides of 7Be, 137Cs and 210Pbexcess to determine the relative magnitude of particle residence time in the high elevation Cropp and Whitcombe subwatersheds and the rates of sedimentation. One- and two-box modeling with 7Be and 210Pbexcess was used to determine soil and sediment residence times. Residence time of fine suspended particles is short and particles can travel the length of the river during a single storm, probably due to the short duration, high-intensity rainfalls which produce rapidly moving, steep flood waves. The readily detected peak of 137Cs activity in Cropp terrace and Hokitika gorge soils yielded sedimentation rates of 0.06-0.12 cm yr-1. At the Cropp terrace, inventory models of 210Pbexcess yield soil accumulation rates significantly less than those determined using the 137Cs activity peak. We attribute the differences to overestimation of 210Pbexcess in surface soils and to contrasting fallout fluxes, geochemical behavior and radionuclide contents of sedimenting materials. Total inventories of 210Pbexcess in soils greatly exceed the expected direct atmospheric deposition, suggesting that lateral transport of this nuclide occurs within the watershed. At the Hokitika gorge, all nuclides studied yielded similar sedimentation rates, confirming the potential of 210Pbexcess for determining sedimentation rates in New Zealand watersheds with very low 137Cs inventories.

Transuranic isotopes and 90Sr in attic dust in the vicinity of two nuclear establishments in northern Germany.

PubMed

Schmitz-Feuerhake, I; Mietelski, J W; Gaca, P

2003-05-01

Attic dust was chosen as the test medium in order to search for traces of man-made bone seeking alpha and beta emitters. The samples were taken from 5 houses in the community of Elbmarsch situated at the river Elbe, adjacent to the Krümmel nuclear power plant and the nuclear research center of Geesthacht. Five houses in other regions of northern Germany were taken as a control. 238Pu, (239,240)Pu, 241Am, and 244Cm were measured by alpha spectrometry after chemical separation. Additionally, 241Pu was measured by liquid scintillation spectrometry, and the fission product 90Sr was measured in a separate investigation. All nuclides except 244Cm showed activities above the detection limit in the Elbmarsch samples and an elevated mean concentration compared to the control. It can be concluded from the activity ratio 241Am/(239,240)Pu that the Elbmarsch contamination cannot be accounted for by the background levels of transuranic nuclides resulting from weapons fallout. The derived release of alpha emitters is assumed to have contributed to the induction of a leukemia cluster in children, which was observed in Elbmarsch between 1990 and 1996.

Simulations of Terrestrial in-situ Cosmogenic-Nuclide Production

NASA Technical Reports Server (NTRS)

Reedy, R. C.; Nishiizumi, K.; Lal, D.; Arnold, J. R.; Englert, P. A. J.; Klein, J.; Middleton, R.; Jull, A. J. T.; Donahue, D. J.

1994-01-01

Targets of silicon and silicon dioxide were irradiated with spallation neutrons to simulate the production of long-lived radionuclides in the surface of the Earth. Gamma-ray spectroscopy was used to measure Be-7 and Na-22, and accelerator mass spectrometry was used to measure Be-10, C-14, and Al-26. The measured ratios of these nuclides are compared with calculated ratios and with ratios from other simulations and agree well with ratios inferred from terrestrial samples.

Simulation of decay processes and radiation transport times in radioactivity measurements

NASA Astrophysics Data System (ADS)

García-Toraño, E.; Peyres, V.; Bé, M.-M.; Dulieu, C.; Lépy, M.-C.; Salvat, F.

2017-04-01

The Fortran subroutine package PENNUC, which simulates random decay pathways of radioactive nuclides, is described. The decay scheme of the active nuclide is obtained from the NUCLEIDE database, whose web application has been complemented with the option of exporting nuclear decay data (possible nuclear transitions, branching ratios, type and energy of emitted particles) in a format that is readable by the simulation subroutines. In the case of beta emitters, the initial energy of the electron or positron is sampled from the theoretical Fermi spectrum. De-excitation of the atomic electron cloud following electron capture and internal conversion is described using transition probabilities from the LLNL Evaluated Atomic Data Library and empirical or calculated energies of released X rays and Auger electrons. The time evolution of radiation showers is determined by considering the lifetimes of nuclear and atomic levels, as well as radiation propagation times. Although PENNUC is designed to operate independently, here it is used in conjunction with the electron-photon transport code PENELOPE, and both together allow the simulation of experiments with radioactive sources in complex material structures consisting of homogeneous bodies limited by quadric surfaces. The reliability of these simulation tools is demonstrated through comparisons of simulated and measured energy spectra from radionuclides with complex multi-gamma spectra, nuclides with metastable levels in their decay pathways, nuclides with two daughters, and beta plus emitters.

Po-210 and Pb-210 as atmospheric tracers and global atmospheric Pb-210 fallout: a review.

PubMed

Baskaran, M

2011-05-01

Over the past ∼ 5 decades, the distribution of (222)Rn and its progenies (mainly (210)Pb, (210)Bi and (210)Po) have provided a wealth of information as tracers to quantify several atmospheric processes that include: i) source tracking and transport time scales of air masses; ii) the stability and vertical movement of air masses iii) removal rate constants and residence times of aerosols; iv) chemical behavior of analog species; and v) washout ratios and deposition velocities of aerosols. Most of these applications require that the sources and sink terms of these nuclides are well characterized. Utility of (210)Pb, (210)Bi and (210)Po as atmospheric tracers requires that data on the (222)Rn emanation rates is well documented. Due to low concentrations of (226)Ra in surface waters, the (222)Rn emanation rates from the continent is about two orders of magnitude higher than that of the ocean. This has led to distinctly higher (210)Pb concentrations in continental air masses compared to oceanic air masses. The highly varying concentrations of (210)Pb in air as well the depositional fluxes have yielded insight on the sources and transit times of aerosols. In an ideal enclosed air mass (closed system with respect to these nuclides), the residence times of aerosols obtained from the activity ratios of (210)Pb/(222)Rn, (210)Bi/(210)Pb, and (210)Po/(210)Pb are expected to agree with each other, but a large number of studies have indicated discordance between the residence times obtained from these three pairs. Recent results from the distribution of these nuclides in size-fractionated aerosols appear to yield consistent residence time in smaller-size aerosols, possibly suggesting that larger size aerosols are derived from resuspended dust. The residence times calculated from the (210)Pb/(222)Rn, (210)Bi/(210)Pb, and (210)Po/(210)Pb activity ratios published from 1970's are compared to those data obtained in size-fractionated aerosols in this decade and possible reasons for the discordance is discussed with some key recommendations for future studies. The existing global atmospheric inventory data of (210)Pb is re-evaluated and a 'global curve' for the depositional fluxes of (210)Pb is established. A current global budget for atmospheric (210)Po and (210)Pb is also established. The relative importance of dry fallout of (210)Po and (210)Pb at different latitudes is evaluated. The global values for the deposition velocities of aerosols using (210)Po and (210)Pb are synthesized. Copyright © 2010 Elsevier Ltd. All rights reserved.

Reconstruction of local fallout composition and gamma-ray exposure in a village contaminated by the first USSR nuclear test in the Semipalatinsk nuclear test site in Kazakhstan.

PubMed

Imanaka, Tetsuji; Yamamoto, Masayoshi; Kawai, Kenta; Sakaguchi, Aya; Hoshi, Masaharu; Chaizhunusova, Nailya; Apsalikov, Kazbek

2010-11-01

After the disintegration of the USSR in end of 1991, it became possible for foreign scientists to visit Kazakhstan, in order to investigate the radiological consequences of nuclear explosions that had been conducted at the Semipalatinsk nuclear test site (SNTS). Since the first visit in 1994, our group has been continuing expeditions for soil sampling at various areas around SNTS. The current level of local fallout at SNTS was studied through γ-spectrometry for (137)Cs as well as α-spectrometry for (239,240)Pu. Average values of soil inventory from wide areas around SNTS were 3,500 and 3,700 Bq m(-2) for (137)Cs and (239,240)Pu, respectively, as of January 1, 2000. The average level of (137)Cs is comparable to that in Japan due to global fallout, while the level of (239,240)Pu is several tens of times larger than that in Japan. Areas of strong contamination were found along the trajectories of radioactive fallout, information on which was declassified after the collapse of the USSR. Our recent efforts of soil sampling were concentrated on the area around the Dolon village heavily affected by the radioactive plume from the first USSR atomic bomb test in 1949 and located 110 km east from ground zero of the explosion. Using soil inventory data, retrospective dosimetry was attempted by reconstructing γ-ray exposure from fission product nuclides deposited on the ground. Adopting representative parameters for the initial (137)Cs deposition (13 kBq m(-2)), the refractory/volatile deposition ratio (3.8) and the plume arrival time after explosion (2.5 h), an absorbed dose in air of 600 mGy was obtained for the 1-year cumulative dose in Dolon village, due to the first bomb test in 1949. Considering possible ranges of the parameters, 350 and 910 mGy were estimated for high and low cases of γ-ray dose in air, respectively. It was encouraging that the deduced value was consistent with other estimations using thermal luminescence and archived monitoring data. The present method can be applied to other settlements affected by local fallout from SNTS.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simpson, H.J.; Trier, R.M.

We have obtained a large set of sediment cores from the Hudson estuary through much of the ambient salinity range. A number of core sections and samples of suspended particles have been analyzed for /sup 137/Cs, /sup 134/Cs and /sup 60/Co by direct gamma counting, and /sup 239/Pu, /sup 240/Pu, and /sup 238/Pu by alpha spectrometry. The distribution of both /sup 137/Cs and /sup 239/Pu, /sup 240/Pu indicates rapid accumulation in marginal cover areas, and especially in the harbor region adjacent to New York City. The distributions of both /sup 137/Cs and /sup 239/Pu, /sup 240/Pu are similar in surfacemore » sediments and with depth in cores, but there are deviations from the fallout ratio due to addition of reactor /sup 137/Cs and loss of /sup 137/Cs from the particle phases at higher salinities. Measureable amounts of reactor-derived /sup 134/Cs and /sup 60/Co are found in nearly all sediment samples containing appreciable /sup 137/Cs, between 15 km upstream of Indian Point and the downstream extent of our sampling, 70 km south of the reactor. Accumulations of /sup 239/Pu, /sup 240/Pu in New York harbor sediments are more than an order of magnitude greater than the fallout delivery rate. The most likely explanation is accumulation of fine particles in the harbor which have been transported from upstream areas of the Hudson. Our evidence so far indicates that Indian Point is probably not a significant source of /sup 239/Pu, /sup 240/Pu or /sup 238/Pu compared with the fallout burden of these nuclides already in the sediments.« less

Sediment transport and Hg recovery in Lavaca Bay, as evaluated from radionuclide and Hg distributions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santschi, P.H.; Allison, M.A.; Asbill, S.

1999-02-01

Mercury was released in the late 1960s from a chloralkali facility managed by ALCOA and deposited into sediments of Lavaca Bay, TX. Sediments have recorded this event as a well-defined subsurface concentration maximum. Radionuclide, mercury, X-radiography, and grain size data from sediment cores taken in 1997 at 15 stations in Lavaca bay were used to assess sediment and Hg movements in the bay. Sediment accumulation rates were calculated from bomb fallout nuclide ({sup 137}Cs, {sup 239,240}Pu) peaks in 1963 and from the steady-state delivery of {sup 210}Pb from the atmosphere. Sedimentation rates are highest at near-shore sites near the ALCOAmore » facility and generally decrease away from shore. Sedimentation rates in some areas are likely influenced by anthropogenic activities such as dredging. Particle reworking, as assessed from {sup 7}Be measurements, is generally restricted to the upper 2--7 cm of sediments. Numerical simulations of Hg profiles using measured sedimentation and mixing parameters indicate that at most sites high remnant mercury concentrations at 15--60 cm depth cannot supply substantial amounts of Hg to surface sediments. Assuming no future Hg supplies, Hg concentrations in surface sediments are predicted to decrease exponentially with a recovery half-time of 4 {+-} 2 years.« less

Radioactivity in books printed in Japan: its source and relation to the year of issue.

PubMed

Kobashi, A

1996-06-01

The radioactivities of the naturally occurring radionuclides (226Ra, 228Ra, 228Th and 40K) and a fallout nuclide (137Cs) in books produced in Japan in the 20th century were measured by gamma-ray spectrometry to obtain information on radiation emitted from books. The respective concentration ranges of 226Ra, 228Ra, 228Th, 40K, and 137Cs were 0.2-6.4, 0.4-11.2, 0.3-11.3, 1-112, and 0-3 Bq kg-1. X-ray diffraction spectra of the papers used in book printing showed that pyrophyllite, talc, kaolinite, and calcium carbonate were contained as fillers. A comparison of the radioactivity contents of the pulp and filler indicated that most of 226Ra, 228Ra, and 228Th in the books was present in the filler whereas 137Cs was in the pulp. The pattern of the concentration of each nuclide vs. the year of issue of the book was investigated. Patterns for the naturally occurring radionuclides were similar and were explained by the kinds of filler used. The pattern for 137Cs differed from the patterns of the naturally occurring radionuclides, having a marked peak in the mid-1960s.

Feasibility study of nuclear transmutation by negative muon capture reaction using the PHITS code

NASA Astrophysics Data System (ADS)

Abe, Shin-ichiro; Sato, Tatsuhiko

2016-06-01

Feasibility of nuclear transmutation of fission products in high-level radioactive waste by negative muon capture reaction is investigated using the Particle and Heave Ion Transport code System (PHITS). It is found that about 80 % of stopped negative muons contribute to transmute target nuclide into stable or short-lived nuclide in the case of 135Cs, which is one of the most important nuclide in the transmutation. The simulation result also indicates that the position of transmutation is controllable by changing the energy of incident negative muon. Based on our simulation, it takes approximately 8.5 × 108years to transmute 500 g of 135Cs by negative muon beam with the highest intensity currently available.

First Volcanological-Probabilistic Pyroclastic Density Current and Fallout Hazard Map for Campi Flegrei and Somma Vesuvius Volcanoes.

NASA Astrophysics Data System (ADS)

Mastrolorenzo, G.; Pappalardo, L.; Troise, C.; Panizza, A.; de Natale, G.

2005-05-01

Integrated volcanological-probabilistic approaches has been used in order to simulate pyroclastic density currents and fallout and produce hazard maps for Campi Flegrei and Somma Vesuvius areas. On the basis of the analyses of all types of pyroclastic flows, surges, secondary pyroclastic density currents and fallout events occurred in the volcanological history of the two volcanic areas and the evaluation of probability for each type of events, matrixs of input parameters for a numerical simulation have been performed. The multi-dimensional input matrixs include the main controlling parameters of the pyroclasts transport and deposition dispersion, as well as the set of possible eruptive vents used in the simulation program. Probabilistic hazard maps provide of each points of campanian area, the yearly probability to be interested by a given event with a given intensity and resulting demage. Probability of a few events in one thousand years are typical of most areas around the volcanoes whitin a range of ca 10 km, including Neaples. Results provide constrains for the emergency plans in Neapolitan area.

Effects of bulk composition on production rates of cosmogenic nuclides in meteorites

NASA Technical Reports Server (NTRS)

Masarik, Jozef; Reedy, Robert C.

1993-01-01

The bulk chemical composition of meteorites has been suggested as a main factor influencing the production of cosmogenic nuclides. Numerical simulations with Los Alamos Monte Carlo production and transport codes were done for Ne-21/Ne-22 ratios and Ar-38 production rates in meteorites with a wide range of compositions. The calculations show that an enhanced flux of low-energy secondary particles in metal-rich phases is the essential key for the explanation of experimentally observed differences in nuclide production processes in various meteorite classes.

Distribution and flux of 238Pu, 239,240Pu, 241Am, 137Cs and 210Pb to high arctic lakes in the Thule district (Greenland).

PubMed

Eriksson, M; Holm, E; Roos, P; Dahlgaard, H

2004-01-01

Environmental samples (soil, sediment and lake water) in the Thule area (NW Greenland) have been studied to assess the contamination of radionuclides originating from a nuclear weapons accident (the Thule accident in 1968). Four lakes were chosen at different distances from the point of impact with the Thule air base community situated in between. The sedimentation rates in the lakes varied from 0.4 mm a(-1) (5 mg cm(-2) a(-1)) to 1.6 mm a(-1) (82 mg cm(-2) a(-1)). With these sedimentation rates, it is not possible to resolve the (239,240)Pu global fallout peak from a possible (239,240)Pu "accident" peak in the sediment depth profiles. However, the (239,240)Pu/(137)Cs and the (238)Pu/(239,240)Pu ratios agreed well with global fallout ratios, indicating that plutonium originating from the accident had not reached these lakes. This also indicates that the Thule air base community has probably only been exposed to radionuclides from the accident to a very limited extent. A limited study showed that (210)Pb could not be used as a normalizing nuclide to explain the transport of transuranic elements from the catchment area to the lake, i.e. (210)Pb has a different transport mechanism from that of the transuranic elements studied in this investigation.

Cryoconites from Alpine glaciers: Radionuclide accumulation and age estimation with Pu and Cs isotopes and 210Pb.

PubMed

Wilflinger, T; Lettner, H; Hubmer, A; Bossew, P; Sattler, B; Slupetzky, H

2018-06-01

Cryoconites ("cold dust", derived from the Greek) are aeolian sediments accumulated on glacier surfaces. In cryoconites from the surface of the Stubacher Sonnblickkees, a temperate Austrian glacier, extremely high activity concentrations of artificial and natural radionuclides were found. Artificial radionuclides stem from two clearly distinguishable sources, global fallout from the nuclear weapons testing era deposited over a period of years until roughly 1966 and the fallout from Chernobyl in 1986, which was essentially deposited as a single input during one week. Anthropogenic radionuclides identified were 137 Cs, 134 Cs, 238 Pu, 239+240 Pu, 90 Sr, 241 Am, 60 Co, 125 Sb, 154 Eu, and 207 Bi. The naturally occurring radionuclides detected were the long-lived radon decay product 210 Pb, the primordial radionuclide 4  K and the cosmogenic 7 Be. Isotopic ratios of 134 Cs/ 137 Cs and 239+240 Pu/ 238 Pu were used to separate the nuclide inventory into the contributions of the two aforementioned sources, which show varying degrees of mixing and provide information on the mixing age of the cryoconites. Since isotopic ratios of Pu often have high uncertainties due to low absolute concentrations, age estimation based on this method can be quite inaccurate. Additional information about the age of cryoconites was obtained through analysis of 210 Pb, which is constantly deposited over time. Copyright © 2017. Published by Elsevier Ltd.

Mapping Nuclear Fallout Using the Weather Research & Forecasting (WRF) Model

DTIC Science & Technology

2012-09-01

relevant modules, originally designed to predict the settling of volcanic ash, such that a stabilized cloud of nuclear particulate is initialized...within the model. This modified code is then executed for various atmospheric test explosions and the results are qualitatively and quantitatively...HYSPLIT Simulation ....................................... 44  Figure 7. WRF Fallout Prediction for Test Shot George, 0.8 R/h at H+1

Reconstruction of doses and deposition in the western trace from the Chernobyl accident.

PubMed

Sikkeland, T; Skuterud, L; Goltsova, N I; Lindmo, T

1997-05-01

A model is presented for the explosive cloud of particulates that produced the western trace of high radioactive ground contamination in the Chernobyl accident on 26 April 1986. The model was developed to reproduce measured dose rates and nuclide contamination and to relate estimated doses to observed changes in: (1) infrared emission from the foliage and (2) morphological and histological structures of individual pines. Dominant factors involved in ground contamination were initial cloud shape, particle size distribution, and rate of particle fallout. At time of formation, the cloud was assumed to be parabolical and to contain a homogeneous distribution of spherically shaped fuel particulates having a log-normal size distribution. The particulates were dispersed by steady winds and diffusion that produced a straight line deposition path. The analysis indicates that two clouds, denoted by Cloud I and Cloud II, were involved. Fallout from the former dominated the far field region and fallout from latter the region near the reactor. At formation they had a full width at half maximum of 1800 m and 500 m, respectively. For wind velocities of 5-10 m s(-1) the particulates' radial distribution at formation had a standard deviation and mode of 1.8 microm and 0.5 microm, respectively. This distribution corresponds to a release of 390 GJ in the runaway explosion. The clouds' height and mass are not uniquely determined but are coupled together. For an initial height of 3,600 m, Cloud I contained about 400 kg fuel. For Cloud II the values were, respectively, 1,500 m and 850 kg. Loss of activities from the clouds is found to be small. Values are obtained for the rate of radionuclide migration from the deposit. Various types of biological damage to pines, as reported in the literature, are shown to be mainly due to ionizing radiation from the deposit by Cloud II. A formula is presented for the particulate size distribution in the trace area.

The {sup 129}Iodine bomb pulse recorded in Mississippi River Delta sediments: Results from isotopes of I, Pu, Cs, Pb, and C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oktay, S.D.; Santschi, P.H.; Moran, J.E.

2000-03-01

Anthropogenic sources from nuclear reprocessing discharges and bomb test fallout have completely overwhelmed the natural signal on the surface of the earth in the last 50 years. However, the transfer functions in and out of environmental compartments are not well known due to temporal variations in the sources of {sup 129}I and to a lack of knowledge regarding the forms of iodine. From a vertical profile of {sup 129}I/{sup 127}I ratios in sediments located in the Mississippi Delta region in approximately 60 meters water depth, the {sup 129}I input function to this region was reconstructed. Dates in the core weremore » assigned based on the plutonium peak at 20 cm depth (assumed to have been deposited in 1963) and the excess {sup 210}Pb profile in the same depth interval, and below that, based on the steadily decreasing {sup 240}Pu/{sup 239}Pu ratios from a ratio of 0.18 at 22 cm to 0.05 at 57 cm depth, the 1953 horizon. Atom ratios of {sup 129}I/{sup 137}I Cs, decay corrected to 1962, the year of maximum radionuclide production, are about 0.3, very close to the production ratios of about 0.2 during atomic bomb tests. This evidence, combined with other observations, strongly suggests that {sup 129}I in Mississippi River Delta sediments originates from atomic bomb fallout eroded from soils of the Mississippi River drainage basin, with little alteration of the isotopic ratios during transport from watershed to coastal deposits. Based on these observations and on laboratory evidence, the authors propose a conceptual model which explains this correspondence and the low {sup 129}I/{sup 127}I ratios. Differences in mobilities of the different chemical forms of {sup 129}I and {sup 127}I, as well as the variances in chemical forms of {sup 129}I from nuclear bomb fallout versus nuclear fuel reprocessing, are proposed to have created such a correspondence between I-isotope ratios and bomb fallout nuclides, without revealing recent inputs from nuclear fuel reprocessing releases to the northern hemisphere observed in watersheds of the USA and Europe.« less

Accelerator experiments on the contribution of secondary particles to the production of cosmogenic nuclides in meteorites

NASA Technical Reports Server (NTRS)

Dragovitsch, P.; Englert, P.

1985-01-01

Through the interaction of galactic cosmic particle radiation (GCR) a wide variety of cosmogenic nuclides is produced in meteorites. They provide historical information about the cosmic radiation and the bombarded meteorites. An important way to understand the production mechanisms of cosmogenic nuclides in meteorites is to gather information about the depth and size dependence of the build-up of Galactic Rays Cosmic-secondary particles within meteorites of different sizes and chemical compositions. Simulation experiments with meteorite models offer an alternative to direct observation providing a data basis to describe the development and action of the secondary cascade induced by the GCR in meteorites.

EML Gamma Spectrometry Data Evaluation Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Decker, Karin M.

2001-01-01

This report presents the results of the analyses for the third EML Gamma Spectrometry Data Evaluation Program (October 1999). This program assists laboratories in providing more accurate gamma spectra analysis results and provides a means for users of gamma data to assess how a laboratory performed on various types of gamma spectrometry analyses. This is accomplished through the use of synthetic gamma spectra. A calibration spectrum, a background spectrum, and three sample spectra are sent to each participant in the spectral file format requested by the laboratory. The calibration spectrum contains nuclides covering the energy range from 59.5 keV tomore » 1836 keV. The participants are told fallout and fission product nuclides could be present. The sample spectra are designed to test the ability of the software and user to properly resolve multiplets and to identify and quantify nuclides in a complicated fission product spectrum. The participants were asked to report values and uncertainties as Becquerel per sample with no decay correction. Thirty-one sets of results were reported from a total of 60 laboratories who received the spectra. Six foreign laboratories participated. The percentage of the results within 1 of the expected value was 68, 33, and 46 for samples 1, 2, and 3, respectively. From all three samples, 18% of the results were more than 3 from the expected value. Eighty-three (12%) values out of a total of 682 expected results were not reported for the three samples. Approximately 30% of these false negatives were due the laboratories not reporting 144Pr in sample 2 which was present at the minimum detectable activity level. There were 53 false positives reported with 25% of these responses due to problems with background subtraction. The results show improvement in the ability of the software or user to resolve peaks separated by 1 keV. Improvement is still needed either in the analysis report produced by the software or in the review of these results by the users.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, David J.; Strom, Daniel J.

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

Extraterrestrial Studies Using Nuclear Interactions

NASA Technical Reports Server (NTRS)

Reedy, Robert C.

2003-01-01

Cosmogenic nuclides were used to study the recent histories of the aubrite Norton County and the pallasite Brenham using calculated production rates. Calculations were done of the rates for making cosmogenic noble-gas isotopes in the Jovian satellite Europa by the interactions of galactic cosmic rays and especially trapped Jovian protons. Cross sections for the production of cosmogenic nuclides were reported and plans made to measure additional cross sections. A new code, MCNPX, was used to numerically simulate the interactions of cosmic rays with matter and the subsequent production of cosmogenic nuclides. A review was written about studies of extraterrestrial matter using cosmogenic radionuclides. Several other projects were done. Results are reviewed here with references to my recent publications for details.

Release of Bacterial Spores from the Inner Walls of a Stainless Steel Cup Subjected to Thermal Stresses and Mechanical Shock

NASA Technical Reports Server (NTRS)

Wolochow, H.; Chatigny, M.; Hebert, J.

1973-01-01

The release and fallout of particulates from surfaces afforded thermal or impact stress is of concern for control of contamination of Mars from planetary landing vehicles. A metal vessel contaminated by aerosols of spores was used as a model system and the fallout of spores as affected by various mechanisms was examined. Thermal stresses simulating those expected on the Mars lander dislodged approximately .01% of the aerosol deposited surface burden as did a landing shock of 8 to 10G deceleration. Spores imprinted by finger or swab contact yielded similar results. In all cases where repeated cycling of temperature, motion, or shock were employed the majority of fallout occurred in the first cycle. Particles released from the surface were predominantly in the size range 1 to 5 microns.

Modelling Deposition and Erosion rates with RadioNuclides (MODERN) - Part 2: A comparison of different models to convert 239+240Pu inventories into soil redistribution rates at unploughed sites.

PubMed

Arata, Laura; Alewell, Christine; Frenkel, Elena; A'Campo-Neuen, Annette; Iurian, Andra-Rada; Ketterer, Michael E; Mabit, Lionel; Meusburger, Katrin

2016-10-01

Sheet erosion is one of the major threats to alpine soils. To quantify its role and impact in the degradation processes of alpine grasslands, the application of Fallout Radionuclides (FRN) showed very promising results. The specific characteristics of plutonium 239 + 240 ( 239+240 Pu), such as the homogeneous fallout distribution, the long half-life and the cost and time effective measurements make this tracer application for investigating soil degradation in Alpine grasslands more suitable than any other FRN (e.g. 137 Cs). However, the conversion of 239+240 Pu inventories into soil erosion rates remains a challenge. Currently available conversion models have been developed mainly for 137 Cs with later adaptation to other FRN (e.g. Excess 210 Pb, and 7 Be), each model being defined for specific land use (ploughed and/or unploughed) and processes (erosion or deposition). As such, they may fail in describing correctly the distribution of Pu isotopes in the soil. A new conversion model, MODERN, with an adaptable algorithm to estimate erosion and deposition rates from any FRN inventory changes was recently proposed (Arata et al., 2016). In this complementary contribution, the authors compare the application of MODERN to other available conversion models. The results show a good agreement between soil redistribution rates obtained from MODERN and from the models currently used by the FRN scientific community (i.e. the Inventory Method). Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Measurement of curium in marine samples

NASA Astrophysics Data System (ADS)

Schneider, D. L.; Livingston, H. D.

1984-06-01

Measurement of environmentally small but detectable amounts of curium requires reliable, accureate, and sensitive analytical methods. The radiochemical separation developed at Woods Hole is briefly reviewed with specific reference to radiochemical interferences in the alpha spectrometric measurement of curium nuclides and to the relative amounts of interferences expected in different oceanic regimes and sample types. Detection limits for 242 Cm and 244 Cm are ultimately limited by their presence in the 243Am used as curium yield monitor. Environmental standard reference materials are evaluated with regard to curium. The marine literature is reviewed and curium measurements are discussed in relation to their source of introduction to the environment. Sources include ocean dumping of low-level radioactive wastes and discharges from nuclear fuel reporcessing activities, In particular, the question of a detectable presence of 244Cm in global fallout from nuclear weapons testing is addressed and shown to be essentially negligible. Analyses of Scottish coastal sedimantes show traces of 242Cm and 244Cm activity which are believed to originate from transport from sources in the Irish Sea.

Assessment of radionuclides in the soil of residential areas of the Chittagong metropolitan city, Bangladesh and evaluation of associated radiological risk

PubMed Central

Rashed-Nizam, Quazi Muhammad; Rahman, Md. Mashiur; Kamal, Masud; Chowdhury, Mantazul Islam

2015-01-01

Soil samples from the three residential hubs of Chittagong city, Bangladesh were analyzed using gamma spectrometry to estimate radiation hazard due to natural radioactive sources and anthropogenic nuclide 137Cs. The activity concentration of 226Ra was found to be in the range 11–25 Bq.kg−1, 232Th in the range 38–59 Bq.kg−1 and 40K in the range 246–414 Bq.kg−1. These results were used to calculate the radiological hazard parameters including Excess of Lifetime Cancer Risk (ELCR). The estimated outdoor gamma exposure rates were 40.6–63.8 nGy.h−1. The radiation hazard index (radium equivalent activity) ranged from 90–140 Bq.kg−1. The average value of the ELCR was found to be 0.21 × 10−3, which is lower than the world average. Sporadic fallout of 137Cs was observed with an average value of 2.0 Bq.kg−1. PMID:25237039

The new conversion model MODERN to derive erosion rates from inventories of fallout radionuclides

NASA Astrophysics Data System (ADS)

Arata, Laura; Meusburger, Katrin; Frenkel, Elena; A'Campo-Neuen, Annette; Iurian, Andra-Rada; Ketterer, Michael E.; Mabit, Lionel; Alewell, Christine

2016-04-01

The measurement of fallout radionuclides (FRNs) has become one of the most commonly used methods to quantify soil erosion and depositional processes. FRNs include anthropogenic radionuclides (e.g. 137Cs, 239+240Pu) released into the atmosphere during nuclear bomb tests and power plant accidents (e.g Chernobyl, Fukushima-Daiichi), as well as natural radiotracers such as 210Pbex and 7Be. FRNs reach the land surface by dry and wet fallouts from the atmosphere. Once deposited, FRNs are tightly adsorbed by fine soil particles and their subsequent redistribution is mostly associated with soil erosion processes. FRNs methods are based on a qualitative comparison: the inventory (total radionuclide activity per unit area) at a given sampling site is compared to that of a so called reference site. The conversion of FRN inventories into soil erosion and deposition rates is done with a variety of models, which suitability is dependent on the selected FRN, soil cultivation (ploughed or unploughed) and movement (erosion or deposition). The authors propose a new conversion model, which can be easily and comprehensively used for different FRNs, land uses and soil redistribution processes. This new model i.e. MODERN (MOdelling Deposition and Erosion rates with RadioNuclides) considers the precise depth distribution of a given FRN at a reference site, and allows adapting it for any specific site conditions. MODERN adaptability and performance has been tested on two published case studies: (i) a 137Cs study in an alpine and unploughed area in the Aosta valley (Italy) and (ii) a 210Pbex study on a ploughed area located in Romania. The results show a good agreement and a significant correlation (r= 0.91, p<0.0001) between the results of MODERN and the published models currently used by the FRN scientific community (i.e. the Profile Distribution Model and the Mass Balance Model). The open access code and the cost free accessibility of MODERN will ensure the promotion of a wider application of FRNs for investigating soil erosion and sedimentation processes.

Modelling the external radiation exposure from the Chernobyl fallout using data from the Swedish municipality measurement system.

PubMed

Jönsson, Mattias; Tondel, Martin; Isaksson, Mats; Finck, Robert; Wålinder, Robert; Mamour, Afrah; Rääf, Christopher

2017-11-01

In connection with the Chernobyl fallout and the subsequent deposition of radionuclides in Sweden, Swedish municipalities launched a measurement program to monitor the external radiation exposure. This program encompasses measurements of the ambient dose equivalent rate 1 m above ground at selected locations, and repeats those measurements at the same locations at 7-month intervals. Measurement data compiled from the seven locations with the highest deposition were combined with data from aerial surveys since May 1986 of ground deposition of 137 Cs, high-resolution gamma spectrometry performed at four locations in May 1986, and measurements from fixed continuous air gamma rate monitoring stations from 28 April to 15 May 1986. Based on these datasets, a model of the time pattern of the external dose rate in terms of ambient dose equivalent rate from the Chernobyl fallout was developed. The decrease in the ambient dose equivalent rate could, on average, be described by a four-component exponential decay function with effective half-times of 6.8 ± 0.3 d, 104 ± 26 d, 1.0 ± 0.02 y and 5.5 ± 0.09 y, respectively. The predominant contributions to the external dose rate in the first month were from short-lived fission products superseded by 134 Cs and then 137 Cs. Integrated over 70 y and using extrapolation of the curve fits, our model predicts that 137 Cs contributes about 60% and 134 Cs contributes about 30% of the external effective dose at these seven locations. The projected time-integrated 70 y external effective dose to an unshielded person from all nuclides per unit total activity deposition of 137 Cs is estimated to be 0.29 ± 0.0.08 mSv/(kBq m -2 ). These results are in agreement with those found in Chernobyl contaminated Russian forest areas, and emphasize the usefulness of maintaining a long-term and regular measurement program in contaminated areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bayesian estimation of a source term of radiation release with approximately known nuclide ratios

NASA Astrophysics Data System (ADS)

Tichý, Ondřej; Šmídl, Václav; Hofman, Radek

2016-04-01

We are concerned with estimation of a source term in case of an accidental release from a known location, e.g. a power plant. Usually, the source term of an accidental release of radiation comprises of a mixture of nuclide. The gamma dose rate measurements do not provide a direct information on the source term composition. However, physical properties of respective nuclide (deposition properties, decay half-life) can be used when uncertain information on nuclide ratios is available, e.g. from known reactor inventory. The proposed method is based on linear inverse model where the observation vector y arise as a linear combination y = Mx of a source-receptor-sensitivity (SRS) matrix M and the source term x. The task is to estimate the unknown source term x. The problem is ill-conditioned and further regularization is needed to obtain a reasonable solution. In this contribution, we assume that nuclide ratios of the release is known with some degree of uncertainty. This knowledge is used to form the prior covariance matrix of the source term x. Due to uncertainty in the ratios the diagonal elements of the covariance matrix are considered to be unknown. Positivity of the source term estimate is guaranteed by using multivariate truncated Gaussian distribution. Following Bayesian approach, we estimate all parameters of the model from the data so that y, M, and known ratios are the only inputs of the method. Since the inference of the model is intractable, we follow the Variational Bayes method yielding an iterative algorithm for estimation of all model parameters. Performance of the method is studied on simulated 6 hour power plant release where 3 nuclide are released and 2 nuclide ratios are approximately known. The comparison with method with unknown nuclide ratios will be given to prove the usefulness of the proposed approach. This research is supported by EEA/Norwegian Financial Mechanism under project MSMT-28477/2014 Source-Term Determination of Radionuclide Releases by Inverse Atmospheric Dispersion Modelling (STRADI).

Iodine-129 in soils from Northern Ukraine and the retrospective dosimetry of the iodine-131 exposure after the Chernobyl accident.

PubMed

Michel, R; Handl, J; Ernst, T; Botsch, W; Szidat, S; Schmidt, A; Jakob, D; Beltz, D; Romantschuk, L D; Synal, H-A; Schnabel, C; López-Gutiérrez, J M

2005-03-20

Forty-eight soil profiles down to a depth of 40 cm were taken in Russia and Ukraine in 1995 and 1997, respectively, in order to investigate the feasibility of retrospective dosimetry of the 131I exposure after the Chernobyl accident via the long-lived 129I. The sampling sites covered areas almost not affected by fallout from the Chernobyl accident such as Moscow/Russia and the Zhitomir district in Ukraine as well as the highly contaminated Korosten and Narodici districts in Ukraine. 129I was analyzed by radiochemical neutron activation analysis (RNAA) and accelerator mass spectrometry (AMS). 127I was measured for some profiles by RNAA or ion chromatography (IC). The results for 127I demonstrated large differences in the capabilities of the soils to store iodine over long time spans. The depth profiles of 129I and of 137Cs showed large differences in the migration behavior between the two nuclides but also for each nuclide among the different sampling sites. Though it cannot be quantified how much 129I and 137Cs was lost out of the soil columns into deeper depths, the inventories in the columns were taken as proxies for the total inventories. For 129I, these inventories were at least three orders of magnitude higher than a pre-nuclear value of 0.084+/-0.017 mBq m(-2) derived from a soil profile taken in 1939 in Lutovinovo/Russia. From the samples from Moscow and Zhitomir, a pre-Chernobyl 129I inventory of (44+/-24) mBq m(-2) was determined, limiting the feasibility of 129I retrospective dosimetry to areas where the 129I inventories exceed 100 mBq m(-2). Higher average 129I inventories in the Korosten and Narodici districts of 130 and 848 mBq m(-2), respectively, allowed determination of the 129I fallout due to the Chernobyl accident. Based on the total 129I inventories and on literature data for the atomic ratio of 129I/131I=13.6+/-2.8 for the Chernobyl emissions and on aggregated dose coefficients for 131I, the thyroid exposure due to 131I after the Chernobyl accident was estimated for the inhabitants of four villages in the Korosten and of three villages in the Narodici districts. The limitations and uncertainties of the 129I retrospective dosimetry are discussed.

Important parameters for smoke plume rise simulation with Daysmoke

Treesearch

L. Liu; G.L. Achtemeier; S.L. Goodrick; W. Jackson

2010-01-01

Daysmoke is a local smoke transport model and has been used to provide smoke plume rise information. It includes a large number of parameters describing the dynamic and stochastic processes of particle upward movement, fallout, fluctuation, and burn emissions. This study identifies the important parameters for Daysmoke simulations of plume rise and seeks to understand...

Dispersal and fallout simulations for urban consequences management (u)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grinstein, Fernando F; Wachtor, Adam J; Nelson, Matt

2010-01-01

Hazardous chemical, biological, or radioactive releases from leaks, spills, fires, or blasts, may occur (intentionally or accidentally) in urban environments during warfare or as part of terrorist attacks on military bases or other facilities. The associated contaminant dispersion is complex and semi-chaotic. Urban predictive simulation capabilities can have direct impact in many threat-reduction areas of interest, including, urban sensor placement and threat analysis, contaminant transport (CT) effects on surrounding civilian population (dosages, evacuation, shelter-in-place), education and training of rescue teams and services. Detailed simulations for the various processes involved are in principle possible, but generally not fast. Predicting urban airflowmore » accompanied by CT presents extremely challenging requirements. Crucial technical issues include, simulating turbulent fluid and particulate transport, initial and boundary condition modeling incorporating a consistent stratified urban boundary layer with realistic wind fluctuations, and post-processing of the simulation results for practical consequences management. Relevant fluid dynamic processes to be simulated include, detailed energetic and contaminant sources, complex building vortex shedding and flows in recirculation zones, and modeling of particle distributions, including particulate fallout, as well as deposition, re-suspension and evaporation. Other issues include, modeling building damage effects due to eventual blasts, addressing appropriate regional and atmospheric data reduction.« less

New technologies to improve the monitoring of tephra fallouts from Etna: the collaborative system Tefranet

NASA Astrophysics Data System (ADS)

Andronico, Daniele; Ferrari, Ferruccio; Merenda, Riccardo; Reitano, Danilo; Scollo, Simona; Cristaldi, Antonio; Lodato, Luigi; Mangiagli, Salvatore

2016-04-01

During early December 2015, Mt. Etna (Italy) produced 4 paroxysmal events from the Voragine crater in just 3 days. This activity caused ash and lapilli fallout over a wide area extending from the volcanic slopes up to ~100 km from the volcano, affecting numerous villages and the cities of Messina and Reggio Calabria. Monitoring this kind of volcanic activity in order to know the dispersal of tephra fallout in quasi-real time can prove challenging, especially when several paroxysmal events follow each other as during these latest eruptions in December. To tackle similar recurring periods of frequent activity, which have occurred a number of times at Etna over recent years, we devised a collaborative system named Tefranet. The system is easy to use but at the same time designed to rapidly retrieve useful georeferenced information on tephra fallouts from Etna's explosive activity. Tefranet includes a mobile application and a web site, with particular attention to an administration backend tool, making owners of smartphones or other mobile devices participants. The system aims to involve citizens living not only in eastern Sicily (i.e. the area most affected by fallout based on the prevailing winds blowing on Etna), but also those resident at some distance, in areas potentially covered by tephra (more than 60-80 km from the volcano) and that are difficult to reach before the original amounts of tephra on the ground may become altered by anthropic (e.g. car traffic) and atmospheric (wind and rain) factors. The Tefranet community will be informed by the INGV specialists via mobile device in case explosive activity resumes, with users able to visualize all the tephra signals on a map in real time. All kinds of information concerning start/end of the tephra fallout, estimation of the clast dimensions, thickness of the deposit, level of tephra cover on the ground, will be welcomed, especially if accompanied by photos of the deposit and of the eruption plume. Here, we present a simulation of a real eruption case in order to show the potential of the system on improving the mapping of the fallout deposits, reducing the time needed to collect tephra samples and extending the sampling area, and finally helping effectively the study of fallout deposits and explosive eruptions also for research purposes.

Modeling the Dispersal and Deposition of Radionuclides: Lessons from Chernobyl.

ERIC Educational Resources Information Center

ApSimon, H. M.; And Others

1988-01-01

Described are theoretical models that simulate the dispersion of radionuclides on local and global scales following the accident at the Chernobyl nuclear power plant. Discusses the application of these results to nuclear weapons fallout. (CW)

ATTENUATION OF SIMULATED FALLOUT RADIATION BY THE ROOF OF A CONCRETE BLOCKHOUSE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmoke, M.A.; Rexroad, R.E.

1961-08-01

An experiment was carried out to verify theoretical calculations of the effect of roof thickness on the radiation level inside a concrete blockhouse from a plane of gamma radiation on the roof. (auth)

Radiological and hyperfine characterization of soils from the Northeastern region of the Province of Buenos Aires, Argentina

NASA Astrophysics Data System (ADS)

Montes, M. L.; Mercader, R. C.; Taylor, M. A.; Runco, J.; Imbellone, P.; Rivas, P. C.; Desimoni, J.

2011-11-01

The activity concentrations of both natural (238U and 232Th chains and 40K) and anthropogenic (137Cs) radionuclides down along the soil profile have been determined in soil samples collected from inland and coastal areas of the La Plata River, located in the Northeastern region of the Province of Buenos Aires, Argentina. These studies were complemented with 57Fe Mössbauer spectroscopy characterization, pH, texture and organic carbon content measurements. From Mössbauer results, the sample compositions differ from one area to the other. Spectra from both soil samples are dominated by the Fe3+ paramagnetic signal. For soil samples from the coastal area, the α-Fe2O3 contribution is lower, Fe3O4 was not detected, and the relative areas of each spectral contribution are nearly constant with depth. For samples from the inland area, the Fe3+ paramagnetic fraction increases up to 82%, mainly at the expense of the magnetically ordered phase. The main observed activity originates from the decay of 40K (540-750 Bq/kg), followed by 238U (60-92 Bq/kg) and 232Th (37-46 Bq/kg) chains. The activity of 235U was in all the cases lower than the detection limit (LD = 0.02 Bq/kg). The only determined anthropogenic nuclide was 137Cs, arising from the fallout of the Southern Hemisphere nuclear weapon tests. Three of the observed differences in the depth distributions can be described by the dispersion-convection model. A correlation between the natural nuclide activities and the Mössbauer relative fractions was found, whereas no correlation was found between the 137Cs profile and the relative fraction of Fe3O4 or with other iron species.

THE BIOLOGICAL AND GEOGRAPHICAL DISTRIBUTION IN THE IRISH SEA OF RADIOACTIVE EFFLUENT FROM WINDSCALE WORKS 1959 TO 1960

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mauchline, J.

1963-01-01

Investigations to determine the fate of the radioactive effluent which is discharged from Windscale Works into the northeastern Irish Sea were made. The ash contents of 17 species of seaweeds and 67 species of invertebrates common in the sea area were determined. Levels of radioactivity originating from k/sup 40/ and other naturally occurring radioisotopes were investigated and are discussed. A few measurements of nuclides in the sea areas distant from Sellafield were made to assess the contribution to the Irish Sea of nuclides from fallout sources. The levels of BETA activity in the samples of marine organisms decreased by amore » factor of 20 in the first 20 miles of distance north or south from Sellafield. No significant build-up of effluent material has taken place in tlie vicinity of Sellafield during the past 7 years, nor is there evidence of a build- up in any other area. No organisms were found to concentrate fission products by factors greater than those previously known. Typical concentration factors for ruthenium, cerium, and zirconium in seaweeds and invertebrates were of the order of 1000. Values for cesium were about 100 and for strontium less than 40. For fish, the concentration factors tended to be somewhat lower, especially for ruthenium and strontium. Marked differences were found between species and this enables a number of species to be selected for possible use as biological indicators. Of the seaweeds, Laminaria spp: Corallina officinalis, and Ceramium rubrum are suitable. Among the animals the most convenient are the polychaete worms, Balanus porcatus (barnacle), Littorina littorea (winkle), and Crangon vuigaris (shrimp). (auth)« less

Depth distributions of uranium-236 and cesium-137 in the Japan/East Sea; toward the potential use as a new oceanic circulation tracer

NASA Astrophysics Data System (ADS)

Sakaguchi, A.; Kadokura, A.; Steier, P.; Takahashi, Y.; Shizuma, K.; Yamamoto, M.

2012-04-01

137Cs (T1/2=30.2 y) has been spread all over the world as a fission product of atmospheric nuclear weapons tests in the 1960s. This nuclide has been used as a powerful tool for oceanography due to the well-defined origin and conservative behaviour in water . However, the number of atoms has decayed already to one thirds compared with its initial levels, and it will become more difficult to measure. In this situation, we focus on 236U (T1/2=2.342-107 y) as a candidate for a new isotopic tracer for oceanography. The detection of 236U in the environment has become possible only recently, by the development of measuring techniques with high sensitivity based on AMS. Our group showed that global fallout from bomb tests contains 236U, which might be produced as nuclear reactions of 235U(n,γ) and/or 238U(n,3n). So 236U has been therefore globally distributed in the surface environment. Thus, 236U has a similar potential as a tracer for environmental dynamics as 137Cs, especially for oceanography. In this study, a comprehensive attempt was made to measure the concentration of 236U in marine samples such as water, suspended solid and bottom sediments to clarify the environmental behaviour of this isotope. Furthermore, the discussion of the circulation of deep and bottom water in "Miniature Ocean", the Japan Sea, has been attempted. Bottom sediments (4 sites) and seawater samples (7 sites) were collected from the Japan Sea. The sediment core was cut into 1 cm segments from the surface to 5 cm in depth within a few hours after the sampling. About 20 L of seawater samples were collected from some depths in each site, and immediately after the sampling, the water was filtered with 0.45 μm pore-size membrane-filters. After the appropriate pre-treatment for each sample, uranium isotope and 137Cs were measured with AMS and Ge-detector, respectively. 236U was successfully detected for all seawater samples, and 236U/238U atom ratios in seawater were in the range of (0.19-1.75)-10-9. The dissolved 236U concentration showed a subsurface maximum and decreased steeply with depth. The minimum value was found at a depth of 2500 m and bottom (about 3000 m in depth) in the northern and the southern areas, respectively. These profiles are markedly different from that of natural 238U which is nearly constant over the depth, suggesting that 236U has not yet reached steady state. For the SS sample, 236U could not be detected in significant levels. The total 236U inventory of the water column was estimated at 1012-1013 atom/m2. This value is nearly the same as the global fallout level (17.8-1012 atom/m2). 236U was also found in the bottom sediments, and the inventory was about 1/40 compared with that in water column. All above characters are comparable with 137Cs which is anthropogenic conservative nuclide in ocean. Actually, the diffusion coefficients for both nuclides show the nearly same value. The detail discussion including the circulation of deep-water in the Japan Sea will be given in our presentation.

Proceedings of a Workshop on Cosmogenic Nuclide Production Rates

NASA Technical Reports Server (NTRS)

Englert, Peter A. J. (Editor); Reedy, Robert C. (Editor); Michel, Rolf (Editor)

1989-01-01

Abstracts of reports from the proceedings are presented. The presentations were divided into discussion topics. The following general topic areas were used: (1) measured cosmogenic noble gas and radionuclide production rates in meteorite and planetary surface samples; (2) cross-section measurements and simulation experiments; and (3) interpretation of sample studies and simulation experiments.

Meteorological modeling of arrival and deposition of fallout at intermediate distances downwind of the Nevada Test Site.

PubMed

Cederwall, R T; Peterson, K R

1990-11-01

A three-dimensional atmospheric transport and diffusion model is used to calculate the arrival and deposition of fallout from 13 selected nuclear tests at the Nevada Test Site (NTS) in the 1950s. Results are used to extend NTS fallout patterns to intermediate downwind distances (300 to 1200 km). The radioactive cloud is represented in the model by a population of Lagrangian marker particles, with concentrations calculated on an Eulerian grid. Use of marker particles, with fall velocities dependent on particle size, provides a realistic simulation of fallout as the debris cloud travels downwind. The three-dimensional wind field is derived from observed data, adjusted for mass consistency. Terrain is represented in the grid, which extends up to 1200 km downwind of NTS and has 32-km horizontal resolution and 1-km vertical resolution. Ground deposition is calculated by a deposition-velocity approach. Source terms and relationships between deposition and exposure rate are based on work by Hicks. Uncertainty in particle size and vertical distributions within the debris cloud (and stem) allow for some model "tuning" to better match measured ground-deposition values. Particle trajectories representing different sizes and starting heights above ground zero are used to guide source specification. An hourly time history of the modeled fallout pattern as the debris cloud moves downwind provides estimates of fallout arrival times. Results for event HARRY illustrate the methodology. The composite deposition pattern for all 13 tests is characterized by two lobes extending out to the north-northeast and east-northeast, respectively, at intermediate distances from NTS. Arrival estimates, along with modeled deposition values, augment measured deposition data in the development of data bases at the county level; these data bases are used for estimating radiation exposure at intermediate distances downwind of NTS. Results from a study of event TRINITY are also presented.

Particle mixing processes of Chernobyl fallout in deep Norwegian Sea sediments: Evidence for seasonal effects

NASA Astrophysics Data System (ADS)

Balzer, W.

1996-09-01

A 1430 m deep station in the Norwegian Sea (Voering Plateau) was occupied five times between May 1986 and February 1987 to investigate the seasonal variation in sediment mixing rates. Cherbnbyl-derived radiocesium, identified by its high proportion of short-lived 134Cs, was used as a tracer for mixing. Most of the nuclide input arrived at the sediment within a narrow time span in June/early July during the beginning of the seasonal biogenic sedimentation pulse. Measured 137Cs profiles in the sediment over time were compared with modelled distributions calculated with a finite difference scheme. The input function of radiocesium to the sea floor was evaluated from the increase of the total inventory with time. Time-invariant mixing coefficients did not provide reasonable fits to either summer or winter distributions. The best fit was obtained with a rate of mixing proportional to the radiocesium input flux, with an average enhancement factor of 6.6 during the two summer months. It appears that the benthic macrofauna are more active during the food supply season and rapidly ingest/bury freshly sedimented materials.

Joseph Rotblat: influences, scientific achievements and legacy

NASA Astrophysics Data System (ADS)

Underwood, Martin

2008-11-01

Joseph Rotblat was one of the most distinguished nuclear physicists and peace campaigners of the post Second World War period. His peace activities rank alongside those of Albert Einstein and Bertrand Russell; he won the Nobel Peace Prize, jointly with the Pugwash movement, that he helped found. However, he made significant contributions to science, and in particular to the medical applications of accelerators, radiation and radio-nuclides. In this article his early work and influences in Poland are described. He then joined James Chadwick at Liverpool University and began work on the cyclotron recently constructed there. Rotblat then, together with Chadwick, joined the Manhattan Project. This experience was to shape his life. He stayed at Los Alamos for less than a year before walking out. He was suspected of being a spy. Rotblat then became Professor of Physics at St Bartholomew's Medical College and pioneered the use of a 15 MeV linear accelerator in treatment and research. He made fundamental contributions to understanding the effects of the fallout from nuclear bomb tests. He also, together with Patricia Lindop, made important contributions to understanding the biological effects of radiation.

Ash fallout scenarios at Vesuvius: Numerical simulations and implications for hazard assessment

NASA Astrophysics Data System (ADS)

Macedonio, G.; Costa, A.; Folch, A.

2008-12-01

Volcanic ash fallout subsequent to a possible renewal of the Vesuvius activity represents a serious threat to the highly urbanized area around the volcano. In order to assess the relative hazard we consider three different possible scenarios such as those following Plinian, Sub-Plinian, and violent Strombolian eruptions. Reference eruptions for each scenario are similar to the 79 AD (Pompeii), the 1631 AD (or 472 AD) and the 1944 AD Vesuvius events, respectively. Fallout deposits for the first two scenarios are modeled using HAZMAP, a model based on a semi-analytical solution of the 2D advection-diffusion-sedimentation equation. In contrast, fallout following a violent Strombolian event is modeled by means of FALL3D, a numerical model based on the solution of the full 3D advection-diffusion-sedimentation equation which is valid also within the atmospheric boundary layer. Inputs for models are total erupted mass, eruption column height, bulk grain-size, bulk component distribution, and a statistical set of wind profiles obtained by the NCEP/NCAR re-analysis. We computed ground load probability maps for different ash loadings. In the case of a Sub-Plinian scenario, the most representative tephra loading maps in 16 cardinal directions were also calculated. The probability maps obtained for the different scenarios are aimed to give support to the risk mitigation strategies.

N values estimation based on photon flux simulation with Geant4 toolkit.

PubMed

Sun, Z J; Danjaji, M; Kim, Y

2018-06-01

N values are routinely introduced in photon activation analysis (PAA) as the ratio of special activities of product nuclides to compare the relative intensities of different reaction channels. They determine the individual activities of each radioisotope and the total activity of the sample, which are the primary concerns of radiation safety. Traditionally, N values are calculated from the gamma spectroscopy in real measurements by normalizing the activities of individual nuclides to the reference reaction [ 58 Ni(γ, n) 57 Ni] of the nickel monitor simultaneously irradiated in photon activation. Is it possible to use photon flux simulated by Monte Carlo software to calculate N values even before the actual irradiation starts? This study has applied Geant4 toolkit, a popular platform of simulating the passage of particles through matter, to generate photon flux in the samples. Assisted with photonuclear cross section from IAEA database, it is feasible to predict N values in different experimental setups for simulated target material. We have validated of this method and its consistency with Geant4. Results also show that N values are highly correlated with the beam parameters of incoming electrons and the setup of the electron-photon converter. Copyright © 2018 Elsevier Ltd. All rights reserved.

Modelling the diffusive transport and remobilisation of 137Cs in sediments: The effects of sorption kinetics and reversibility

NASA Astrophysics Data System (ADS)

Smith, J. T.; Comans, R. N. J.

1996-03-01

In determining the mobility of ions in sediments it is important to take account of the solid phase sorption and speciation. Measurements were made of activity depth profiles of 137Cs from fallout from Nuclear Weapons Testing and from the Chernobyl accident in two lake sediments. The fraction of 137Cs in the aqueous, exchangeably sorbed and "fixed" phases was determined at each depth interval. A model was developed to simulate the transport of 137Cs in these sediments, taking account of changes in sorption properties as the concentration of the competing ammonium ion changes with depth, as well as transfers of activity to less-exchangeable sites on the solids. The model simulations give reasonable agreement with experimental data, and the fitted rate constant for slow transfers to less-exchangeable sites ( T1/2 = 50-125 d) is in agreement with independent measurements. The modelling gave evidence for a reverse reaction from less-exchangeable to exchangeable sites with a half-life of order 10 y. Model results were compared with those generated by a physical mixing model and the standard molecular diffusion model assuming equilibrium sorption to the solid phase. Estimates were made of the remobilisation of Chernobyl 137Cs from these sediments to the water column: predicted rates vary from around 3% of the inventory per year 2 years after the fallout event to 0.04% per year 30 years after the fallout.

A methodological approach to a realistic evaluation of skin absorbed doses during manipulation of radioactive sources by means of GAMOS Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Italiano, Antonio; Amato, Ernesto; Auditore, Lucrezia; Baldari, Sergio

2018-05-01

The accurate evaluation of the radiation burden associated with radiation absorbed doses to the skin of the extremities during the manipulation of radioactive sources is a critical issue in operational radiological protection, deserving the most accurate calculation approaches available. Monte Carlo simulation of the radiation transport and interaction is the gold standard for the calculation of dose distributions in complex geometries and in presence of extended spectra of multi-radiation sources. We propose the use of Monte Carlo simulations in GAMOS, in order to accurately estimate the dose to the extremities during manipulation of radioactive sources. We report the results of these simulations for 90Y, 131I, 18F and 111In nuclides in water solutions enclosed in glass or plastic receptacles, such as vials or syringes. Skin equivalent doses at 70 μm of depth and dose-depth profiles are reported for different configurations, highlighting the importance of adopting a realistic geometrical configuration in order to get accurate dosimetric estimations. Due to the easiness of implementation of GAMOS simulations, case-specific geometries and nuclides can be adopted and results can be obtained in less than about ten minutes of computation time with a common workstation.

Comparison of simulations with PHITS and HIBRAC with experimental data in the context of particle therapy monitoring

PubMed Central

Rohling, Heide; Sihver, Lembit; Priegnitz, Marlen; Enghardt, Wolfgang; Fiedler, Fine

2014-01-01

Therapeutic irradiation with protons and ions is advantageous over radiotherapy with photons due to its favorable dose deposition. Additionally, ion beams provide a higher relative biological effectiveness than photons. For this reason, an improved treatment of deep-seated tumors is achieved and normal tissue is spared. However, small deviations from the treatment plan can have a large impact on the dose distribution. Therefore, a monitoring is required to assure the quality of the treatment. Particle therapy positron emission tomography (PT-PET) is the only clinically proven method which provides a non-invasive monitoring of dose delivery. It makes use of the β+-activity produced by nuclear fragmentation during irradiation. In order to evaluate these PT-PET measurements, simulations of the β+-activity are necessary. Therefore, it is essential to know the yields of the β+-emitting nuclides at every position of the beam path as exact as possible. We evaluated the three-dimensional Monte-Carlo simulation tool PHITS (version 2.30) [ 1] and the 1D deterministic simulation tool HIBRAC [ 2] with respect to the production of β+-emitting nuclides. The yields of the most important β+-emitting nuclides for carbon, lithium, helium and proton beams have been calculated. The results were then compared with experimental data obtained at GSI Helmholtzzentrum für Schwerionenforschung Darmstadt, Germany. GEANT4 simulations provide an additional benchmark [ 3]. For PHITS, the impact of different nuclear reaction models, total cross-section models and evaporation models on the β+-emitter production has been studied. In general, PHITS underestimates the yields of positron-emitters and cannot compete with GEANT4 so far. The β+-emitters calculated with an extended HIBRAC code were in good agreement with the experimental data for carbon and proton beams and comparable to the GEANT4 results, see [ 4] and Fig. 1. Considering the simulation results and its speed compared with three-dimensional Monte-Carlo tools, HIBRAC is a good candidate for the implementation in clinical routine PT-PET. Fig 1.Depth-dependent yields of the production of 11C and 15O during proton irradiation of a PMMA target with 140 MeV [ 4].

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jaffke, Patrick John

This acts as a short note on the effects of varying the value of the endpoints of the thermal, epithermal, and fast flux groups. As expected, varying these endpoints can alter the value of the cross-section for a given nuclide. This effect is quantified in this note for an important nuclide in reactor simulations, 238U. Uranium-238 is responsible for the production of Plutonium in most reactors, making it critical to understand all of the 238U capture modes leading to Plutonium. We explicitly quantify the reaction rates for 238U that are altered when we use a given research reactor fluxmore » and vary the endpoint definitions of said flux as well as the reactor position.« less

A MODEL BUILDING CODE ARTICLE ON FALLOUT SHELTERS WITH RECOMMENDATIONS FOR INCLUSION OF REQUIREMENTS FOR FALLOUT SHELTER CONSTRUCTION IN FOUR NATIONAL MODEL BUILDING CODES.

ERIC Educational Resources Information Center

American Inst. of Architects, Washington, DC.

A MODEL BUILDING CODE FOR FALLOUT SHELTERS WAS DRAWN UP FOR INCLUSION IN FOUR NATIONAL MODEL BUILDING CODES. DISCUSSION IS GIVEN OF FALLOUT SHELTERS WITH RESPECT TO--(1) NUCLEAR RADIATION, (2) NATIONAL POLICIES, AND (3) COMMUNITY PLANNING. FALLOUT SHELTER REQUIREMENTS FOR SHIELDING, SPACE, VENTILATION, CONSTRUCTION, AND SERVICES SUCH AS ELECTRICAL…

Algorithm improvement program nuclide identification algorithm scoring criteria and scoring application.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Enghauser, Michael

2016-02-01

The goal of the Domestic Nuclear Detection Office (DNDO) Algorithm Improvement Program (AIP) is to facilitate gamma-radiation detector nuclide identification algorithm development, improvement, and validation. Accordingly, scoring criteria have been developed to objectively assess the performance of nuclide identification algorithms. In addition, a Microsoft Excel spreadsheet application for automated nuclide identification scoring has been developed. This report provides an overview of the equations, nuclide weighting factors, nuclide equivalencies, and configuration weighting factors used by the application for scoring nuclide identification algorithm performance. Furthermore, this report presents a general overview of the nuclide identification algorithm scoring application including illustrative examples.

Fallout: The experiences of a medical team in the care of a Marshallese population accidently exposed to fallout radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conard, R.A.

1992-09-01

This report presents an historical account of the experiences of the Brookhaven Medical Team in the examination and treatment of the Marshallese people following their accidental exposure to radioactive fallout in 1954. This is the first time that a population has been heavily exposed to radioactive fallout, and even though this was a tragic mishap, the medical findings have provided valuable information for other accidents involving fallout such as the recent reactor accident at Chernobyl. Noteworthy has been the unexpected importance of radioactive iodine in the fallout in producing thyroid abnormalities.

Fallout: The experiences of a medical team in the care of a Marshallese population accidentally exposed to fallout radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conard, R.A.

1991-12-31

This report presents an historical account of the experiences of the Brookhaven Medical team in the examination and treatment of the Marshallese people following their accidental exposure to radioactive fallout in 1954. This is the first time that a population has been heavily exposed to radioactive fallout, and even though this was a tragic mishap, the medical findings have provided valuable information for other accidents involving fallout such as the recent reactor accident at Chernobyl. Particularly important has been the unexpected importance of radioactive iodine in the fallout in producing thyroid abnormalities.

Fallout: The experiences of a medical team in the care of a Marshallese population accidentally exposed to fallout radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conard, R.A.

1991-01-01

This report presents an historical account of the experiences of the Brookhaven Medical team in the examination and treatment of the Marshallese people following their accidental exposure to radioactive fallout in 1954. This is the first time that a population has been heavily exposed to radioactive fallout, and even though this was a tragic mishap, the medical findings have provided valuable information for other accidents involving fallout such as the recent reactor accident at Chernobyl. Particularly important has been the unexpected importance of radioactive iodine in the fallout in producing thyroid abnormalities.

Viscous Particle Breakup within a Cooling Nuclear Fireball

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilkinson, J. T.; Knight, K. B.; Dai, Z.

2016-10-04

Following the surface detonation of a nuclear weapon, the Earth’s crust and immediate surroundings are drawn into the fireball and form melts. Fallout is formed as these melts incorporate radioactive material from the bomb vapor and cool rapidly. The resultant fallout plume and dispersion of radioactive contamination is a function of several factors including weather patterns and fallout particle shapes and size distributions. Accurate modeling of the size distributions of fallout forms an important data point for dispersion codes that calculate the aerial distribution of fallout. While morphological evidence for aggregation of molten droplets is well documented in fallout glassmore » populations, the breakup of these molten droplets has not been similarly studied. This study documents evidence that quenched fallout populations preserve evidence of molten breakup mechanisms.« less

Algorithm Improvement Program Nuclide Identification Algorithm Scoring Criteria And Scoring Application - DNDO.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Enghauser, Michael

2015-02-01

The goal of the Domestic Nuclear Detection Office (DNDO) Algorithm Improvement Program (AIP) is to facilitate gamma-radiation detector nuclide identification algorithm development, improvement, and validation. Accordingly, scoring criteria have been developed to objectively assess the performance of nuclide identification algorithms. In addition, a Microsoft Excel spreadsheet application for automated nuclide identification scoring has been developed. This report provides an overview of the equations, nuclide weighting factors, nuclide equivalencies, and configuration weighting factors used by the application for scoring nuclide identification algorithm performance. Furthermore, this report presents a general overview of the nuclide identification algorithm scoring application including illustrative examples.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simpson, H.J.; Williams, S.C.

We have obtained a large set of cores from the Hudson Estuary covering nearly all of the ambient salinity range. A number of core sections have been analyzed for /sup 137/Cs, /sup 134/Cs, /sup 60/Co and /sup 40/K by direct gamma counting and for /sup 239/,/sup 240/Pu and /sup 238/Pu by alpha-spectrometry. Rapid accumulation, up to 20 cm/year, of sediments containing /sup 239/,/sup 240/Pu, /sup 137/Cs, /sup 134/Cs and /sup 60/Co occurs in New York Harbor. Marginal coves upstream from the harbor also serve as depositional environments. The ratio of sediment /sup 239,240/Pu to /sup 137/Cs is higher than themore » fallout ratio in the seaward end of New York Harbor, despite the presence of a significant component of reactor /sup 137/Cs in the sediments, but lower than the range of ratios observed by others for nearshore environments with low sediment deposition rates. A substantial portion of gamma emitting fission product and activation nuclides released from the Indian Point nuclear facility have accumulated in New York Harbor, more than 60 km downstream from the release area. We have not yet established whether local transuranic releases to the Hudson have occurred.« less

Neutron Capture and the Antineutrino Yield from Nuclear Reactors.

PubMed

Huber, Patrick; Jaffke, Patrick

2016-03-25

We identify a new, flux-dependent correction to the antineutrino spectrum as produced in nuclear reactors. The abundance of certain nuclides, whose decay chains produce antineutrinos above the threshold for inverse beta decay, has a nonlinear dependence on the neutron flux, unlike the vast majority of antineutrino producing nuclides, whose decay rate is directly related to the fission rate. We have identified four of these so-called nonlinear nuclides and determined that they result in an antineutrino excess at low energies below 3.2 MeV, dependent on the reactor thermal neutron flux. We develop an analytic model for the size of the correction and compare it to the results of detailed reactor simulations for various real existing reactors, spanning 3 orders of magnitude in neutron flux. In a typical pressurized water reactor the resulting correction can reach ∼0.9% of the low energy flux which is comparable in size to other, known low-energy corrections from spent nuclear fuel and the nonequilibrium correction. For naval reactors the nonlinear correction may reach the 5% level by the end of cycle.

Nuclide Guide and International Chart of Nuclides - 2008

NASA Astrophysics Data System (ADS)

Golashvili, T.

2009-08-01

New versions of Nuclide Guide and Chart of the Nuclides were developed as a result of Russian-Chinese collaboration. The Nuclide Guide contains the basic information on more than 3000 radioactive and stable nuclides. The characteristics of isomers with half-lives more than 1 ms are included. For each nuclide spin, parity, mass of nuclide, magnetic moment (if available), mass excess, half-life or abundance, decay modes, branching ratios, emitted particles, energies of most intense gamma-rays and their intensities, decay energies and mean values of radiation energy per decay are given. For stable and natural long-lived nuclides cross-sections of thermal neutron induced activation are indicated. The information presented in the Guide was compiled from 5 sources: 1) ENSDF-2008, 2) atomic mass evaluation-2005 by Audi and Wapstra, 3) interactive data bases at web-sites , , 4) original evaluations of authors, 5) recent publications. The International Chart ot Nuclides was developed on the basis of information presented in Nuclide Guide.

Natural radionuclide and plutonium content in Black Sea bottom sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strezov, A.; Stoilova, T.; Yordanova, I.

1996-01-01

The content of uranium, thorium, radium, lead, polonium, and plutonium in bottom sediments and algae from two locations at the Bulgarian Black Sea coast have been determined. Some parent:progeny ratios for evaluation of the geochemical behavior of the nuclides have been estimated as well. The extractable and total uranium and thorium are determined by two separate radiochemical procedures to differentiate the more soluble chemical forms of the elements and to estimate the potential hazard for the biosphere and for humans. No distinct seasonal variation as well as no significant change in total and extractable uranium (also for {sup 226}Ra) contentmore » is observed. The same is valid for extractable thorium while the total thorium content in the first two seasons is slightly higher. Our data show that {sup 210}Po content is accumulated more in the sediments than {sup 210}Pb, and the evaluated disequilibria suggest that the two radionuclides belong to more recent sediment layers deposited in the slime samples compared to the silt ones for the different seasons. The obtained values for plutonium are in the lower limits of the data cited in literature, which is quite clear as there are no plutonium discharge facilities at the Bulgarian Black Sea coast. The obtained values for the activity ratio {sup 238}Pu: {sup 239+240}Pu are higher for Bjala sediments compared to those of Kaliakra. The ratio values are out of the variation range for the global contamination with weapon tests fallout plutonium which is probably due to Chernobyl accident contribution. The dependence of natural radionuclide content on the sediment type as well as the variation of nuclide accumulation for two types of algae in two sampling locations for five consecutive seasons is evaluated. No serious contamination with natural radionuclides in the algae is observed. 38 refs., 6 figs., 7 tabs.« less

Shielding and activity estimator for template-based nuclide identification methods

DOEpatents

Nelson, Karl Einar

2013-04-09

According to one embodiment, a method for estimating an activity of one or more radio-nuclides includes receiving one or more templates, the one or more templates corresponding to one or more radio-nuclides which contribute to a probable solution, receiving one or more weighting factors, each weighting factor representing a contribution of one radio-nuclide to the probable solution, computing an effective areal density for each of the one more radio-nuclides, computing an effective atomic number (Z) for each of the one more radio-nuclides, computing an effective metric for each of the one or more radio-nuclides, and computing an estimated activity for each of the one or more radio-nuclides. In other embodiments, computer program products, systems, and other methods are presented for estimating an activity of one or more radio-nuclides.

Naples between two fires: eruptive scenarios for the next eruptions by an integrated volcanological-probabilistic approach.

NASA Astrophysics Data System (ADS)

Mastrolorenzo, G.; Pappalardo, L.; de Natale, G.; Troise, C.; Rossano, S.; Panizza, A.

2009-04-01

Probabilistic approaches based on available volcanological data from real eruptions of Campi Flegrei and Somma-Vesuvius, are assembled in a comprehensive assessment of volcanic hazards at the Neapolitan area. This allows to compare the volcanic hazards related to the different types of events, which can be used for evaluating the conditional probability of flows and falls hazard in case of a volcanic crisis. Hazard maps are presented, based on a rather complete set of numerical simulations, produced using field and laboratory data as input parameters relative to a large range (VEI 1 to 5) of fallout and pyroclastic-flow events and their relative occurrence. The results allow us to quantitatively evaluate and compare the hazard related to pyroclastic fallout and density currents (PDCs) at the Neapolitan volcanoes and their surroundings, including the city of Naples. Due to its position between the two volcanic areas, the city of Naples is particularly exposed to volcanic risk from VEI>2 eruptions, as recorded in the local volcanic succession. Because dominant wind directions, the area of Naples is particularly prone to fallout hazard from Campi Flegrei caldera eruptions in the VEI range 2-5. The hazard from PDCs decreases roughly radially with distance from the eruptive vents and is strongly controlled by the topographic heights. Campi Flegrei eruptions are particularly hazardous for Naples, although the Camaldoli and Posillipo hills produce an effective barrier to propagation to the very central part of Naples. PDCs from Vesuvius eruptions with VEI>4 can cover the city of Naples, whereas even VEI>3 eruptions have a moderate fallout hazard there.

Radiation Doses to Members of the U.S. Population from Ubiquitous Radionuclides in the Body: Part 3, Results, Variability, and Uncertainty

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, David J.; Strom, Daniel J.

This paper is part three of a three-part series investigating annual effective doses to residents of the United States from intakes of ubiquitous radionuclides, including radionuclides occurring naturally, radionuclides whose concentrations are technologically enhanced, and anthropogenic radionuclides. The radionuclides of interest are the 238U series (14 nuclides), the actinium series (headed by 235U; 11 nuclides), and the 232Th series (11 nuclides); primordial radionuclides 87Rb and 40K; cosmogenic and fallout radionuclides 14C and 3H; and purely anthropogenic radionuclides 137Cs-137mBa, 129I and 90Sr-90Y. This series of papers explicitly excludes intakes from inhaling 222Rn, 220Rn, and their short-lived decay products; it also excludesmore » intakes of radionuclides in occupational and medical settings. Part one reviewed, summarized, characterized, and grouped all published and some unpublished data for U.S. residents on ubiquitous radionuclide concentrations in tissues and organs. Part two described the methods used to organize the data collected in part one and segregate it into the ages and genders defined by the study, imputed missing values from the existing data, apportioned activity in bone, and imputed activity in hollow organ contents and the remainder of the body. This paper estimates equivalent doses to target tissues from source regions and maps target tissues to lists of tissues with International Commission on Radiation Protection (ICRP) tissue-weighting factors or to surrogate tissue regions when there is no direct match. Effective doses, using ICRP tissue-weighting factors recommended in 1977, 1990, and 2007, are then calculated, and an upper bound of variability of the effective dose is estimated by calculating the average coefficients of variation (CV), assuming all variance is due to variability. Most of the data were for adult males, whose average annual effective dose is estimated to be 337 μSv (CV = 0.65, geometric mean = 283 μSv, geometric standard deviation sG = 1.81) using 2007 ICRP tissue-weighting factors. This result is between the National Council on Radiation Protection & Measurements’ 1987 estimate of 390 μSv (using 1977 wTs) and its 2009 estimate of 285 μSv (using 2007 wTs) and is higher than the United Nations Scientific Committee on the Effects of Atomic Radiation’s 2000 estimate of 310 μSv (using 1990 wTs). The methods and software developed for this project are sufficiently detailed and sufficiently general to be usable with autopsy data from any or all countries.« less

Manufacture and Testing of an Activation Foil Package for Use in AFIDS

DTIC Science & Technology

2005-03-01

Miller. Nuclides and Isotopes , 16th ed. Lockheed Martin, 2002. 4. Broadhead, Bryan. Sr. Development Staff, Reactor and Fuel Cycle Analysis ...alternative, the concept of using liquid nitrous oxide inside a reactor to simulate large volumes of air was investigated. Simulation using the...weapon. We analyzed whether N2O could replicate large volumes of air in neutron transport experiments since one cubic centimeter of liquid N2O

Personal and Family Survival. Civil Defense Adult Education Course Student Manual.

ERIC Educational Resources Information Center

Office of Civil Defense (DOD), Washington, DC.

A manual providing general orientation on the subject of United States civil defense is presented. It can serve as a home reference and as a tool for an adult education class. The nine chapters are: U.S. Civil Defense, Modern Weapons and Radioactive Fallout, Public Fallout Shelters, Fallout Shelter Occupancy, Fallout Protection at Home, Community…

2017 update of the discoveries of nuclides

NASA Astrophysics Data System (ADS)

Thoennessen, M.

The 2017 update of the discovery of nuclide project is presented. 34 new nuclides were observed for the first time in 2017. However, the assignment of six previously identified nuclides had to be retracted.

Using Principal Component Analysis to Improve Fallout Characterization

DTIC Science & Technology

2017-03-23

between actinide location and elemental composition in fallout from historic atmospheric nuclear weapons testing. Fifty spherical fallout samples were...mathematical approach to solving the complex system of elemental variables while establishing correlations to actinide incorporation within the fallout...1. The double hump curve for uranium-235 showing the effective fission yield by mass number for thermal neutrons. Reproduced with permission from

Planning Guidance for Response to a Nuclear Detonation

DTIC Science & Technology

2009-01-16

Radiation and Fallout One of the primary outputs from a nuclear explosion is radiation . Intense... on the jet streams and have a low-level global impact. Radiation Injuries and Fallout Health Impacts A nuclear explosion will produce dangerous... radiation dose rates based on the quantity of visible fallout. Therefore, visible fallout may possibly be used as an indicator of a direct radiation

Cancer mortality in residents of the terrain-shielded area exposed to fallout from the Nagasaki atomic bombing

PubMed Central

Mine, Mariko; Kondo, Hisayoshi; Matsuda, Naoki; Shibata, Yoshisada; Takamura, Noboru

2018-01-01

Abstract The health effects of radiation exposure from the atomic bomb fallout remain unclear. The objective of the present study is to elucidate the association between low-dose radiation exposure from the atomic bomb fallout and cancer mortality among Nagasaki atomic bomb survivors. Of 77 884 members in the Nagasaki University Atomic Bomb Survivors Cohort, 610 residents in the terrain-shielded area with fallout were selected for this analysis; 1443 residents in the terrain-shielded area without fallout were selected as a control group; and 3194 residents in the direct exposure area were also selected for study. Fifty-two deaths due to cancer in the terrain-shielded fallout area were observed during the follow-up period from 1 January 1970 to 31 December 2012. The hazard ratio for cancer mortality in the terrain-shielded fallout area was 0.90 (95% confidence interval: 0.65–1.24). No increase in the risk of cancer mortality was observed, probably because the dose of the radiation exposure was low for residents in the terrain-shielded fallout areas of the Nagasaki atomic bomb, and also because the number of study subjects was small. PMID:29036510

Fallout risk following a major nuclear attack on the United States.

PubMed

Harvey, T F; Shapiro, C S; Wittler, R F

1992-01-01

Fallout distributions are calculated for nuclear attacks on the contiguous United States. Four attack scenarios are treated, including counterforce and counterforce-countervalue attacks, for meteorological conditions associated with a typical day in summer and one in winter. The countervalue attacks contain mostly airbursts. To determine fallout effects, the population surviving the prompt effects is first calculated. For the prompt effects, a "conflagration-type" model is used. The counterforce attack produces about 8 million prompt deaths, and the counterforce-countervalue case projects 98 million prompt deaths. Partial relocation before attack to low-risk fallout areas at least 15 km from potential strategic targets would result in a decrease in projections of deaths by tens of millions. For fallout risk calculations, only the dose received in the first 48 h (the early or local fallout) is considered. Populations are assumed to be sheltered, with a shelter protection factor profile that varies for a large urban area, a small urban area, or a rural area. With these profiles, without relocation, the fallout fatalities for all four attack scenarios are calculated to be less than one million people. This can be compared to fallout fatalities of about 10 million for a hypothetical unsheltered "phantom" population.

Factors influencing in situ gamma-ray measurements

NASA Astrophysics Data System (ADS)

Loonstra, E. H.; van Egmond, F. M.

2009-04-01

Introduction In situ passive gamma-ray sensors are very well suitable for mapping physical soil properties. In order to make a qualitative sound soil map, high quality input parameters for calibration are required. This paper will focus on the factors that affect the output of in situ passive gamma-ray sensors, the primary source, soil, not taken into account. Factors The gamma-ray spectrum contains information of naturally occurring nuclides 40K, 238U and 232Th and man-made nuclides like 137Cs, as well as the total count rate. Factors that influence the concentration of these nuclides and the count rate can be classified in 3 categories. These are sensor design, environmental conditions and operational circumstances. Sensor design The main elements of an in situ gamma-ray sensor that influence the outcome and quality of the output are the crystal and the spectrum analysis method. Material and size of the crystal determine the energy resolution. Though widely used, NaI crystals are not the most efficient capturer of gamma radiation. Alternatives are BGO and CsI. BGO has a low peak resolution, which prohibits use in cases where man-made nuclides are subject of interest. The material is expensive and prone to temperature instability. CsI is robust compared to NaI and BGO. The density of CsI is higher than NaI, yielding better efficiency, especially for smaller crystal sizes. More volume results in higher energy efficiency. The reduction of the measured spectral information into concentration of radionuclides is mostly done using the Windows analysis method. In Windows, the activities of the nuclides are found by summing the intensities of the spectrum found in a certain interval surrounding a peak. A major flaw of the Windows method is the limited amount of spectral information that is incorporated into the analysis. Another weakness is the inherent use of ‘stripping factors' to account for contributions of radiation from nuclide A into the peak of nuclide B. This can be overcome using Full Spectrum Analysis (FSA). This method incorporates virtually all data present in the measured gamma spectrum. In FSA, a Chi-squared algorithm is used to fit a set of "Standard Spectra" to the measured spectrum. The uncertainty in the FSA method is at least a factor 2 lower compared to the Windows method. Environmental conditions Environmental conditions can influence the signal output and therefore the quality. In general, the density of the medium through which gamma-radiation travels determines the interaction of the radiation with matter and thus affects the sensor readings. Excluding soil as being the source; water is the most important external factor in this respect. The amount of water in soil will affect the signal. In general, energy loss occurs as water content in soil increases. As a result, the nuclide concentrations will be lower. Monte Carlo simulations show a difference of 16% in nuclide concentration for completely dry and fully saturated sandy soils. Another water related issue is rainfall. With rain radon gas, a product of 238U, will precipitate. This causes spectral noise effects. Snow and fog have the same effect to a minor degree. Another aspect is the openness of soil. From experience we know that the concentration of 40K differs if soil is tilled. Finally, on earth there is always radioactive noise present from the galaxy. The "Standard Spectra" used in the FSA method can take noise and geometric effects into account. Operational circumstances During a survey an operator should be aware of the effects of driving speed and measurement height. In general, a larger crystal has better energy efficiency and is therefore more suitable for high speed. E.g. a 70 x 150 mm CsI crystal provides qualitative satisfactory output for soil mapping up to 10 km/hr. Sample locations, however, are best measured during a longer period (3 to 5 minutes). The measurement height affects the measurement resolution; the lower the sensor, the smaller the measured area. In addition, Monte Carlo simulations show that the mass of the survey vehicle has to be taken into account. A large tractor e.g. can lead to spectral shape disruptions of 5 to 10%. Conclusion Several factors can effect the measured concentrations of radioactive nuclides. Potential users should take mentioned factors into account in respect to their needs when building and applying gamma-ray sensors. For purposes of soil mapping the use of FSA method is preferred, as it incorporates several disturbing factors. This allows the user to create a consistent dataset which will lead to a better understanding of the relation between nuclide concentrations and physical soil properties.

Measurement and simulation of the cross sections for nuclide production in {sup nat}W and {sup 181}Ta targets irradiated with 0.04- to 2.6-GeV protons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Titarenko, Yu. E., E-mail: Yury.Titarenko@itep.ru; Batyaev, V. F.; Titarenko, A. Yu.

The cross sections for nuclide production in thin {sup nat}Wand {sup 181}Ta targets irradiated by 0.04-2.6-GeV protons have been measured by direct {gamma} spectrometry using two {gamma} spectrometers with the resolutions of 1.8 and 1.7 keV in the {sup 60}Co 1332-keV {gamma} line. As a result, 1895 yields of radioactive residual product nuclei have been obtained. The {sup 27}Al(p, x){sup 22}Na reaction has been used as a monitor reaction. The experimental data have been compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations.

Measurement and simulation of the cross sections for nuclide production in {sup 93}Nb and {sup nat}Ni targets irradiated with 0.04- to 2.6-GeV protons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Titarenko, Yu. E., E-mail: Yury.Titarenko@itep.ru; Batyaev, V. F.; Titarenko, A. Yu.

The cross sections for nuclide production in thin {sup 93}Nb and {sup nat}Ni targets irradiated by 0.04- to 2.6-GeV protons have been measured by direct {gamma} spectrometry using two {gamma} spectrometers with the resolutions of 1.8 and 1.7 keV in the {sup 60}Co 1332-keV {gamma} line. As a result, 1112 yields of radioactive residual nuclei have been obtained. The {sup 27}Al(p, x){sup 22}Na reaction has been used as a monitor reaction. The experimental data have been compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations.

Measurement and simulation of the cross sections for nuclide production in {sup 56}Fe and {sup nat}Cr targets irradiated with 0.04- to 2.6-GeV protons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Titarenko, Yu. E., E-mail: Yury.Titarenko@itep.ru; Batyaev, V. F.; Titarenko, A. Yu.

The cross sections for nuclide production in thin {sup 56}Fe and {sup nat}Cr targets irradiated by 0.04-2.6-GeV protons are measured by direct {gamma} spectrometry using two {gamma} spectrometers with the resolutions of 1.8 and 1.7 keV for the {sup 60}Co 1332-keV {gamma} line. As a result, 649 yields of radioactive residual product nuclei have been obtained. The {sup 27}Al(p, x){sup 22}Na reaction has been used as a monitor reaction. The experimental data are compared with the MCNPX (BERTINI, ISABEL), CEM03.02, INCL4.2, INCL4.5, PHITS, and CASCADE07 calculations.

Forbush decreases geomagnetic and atmospheric effects cosmogenic nuclides

NASA Technical Reports Server (NTRS)

Flueckiger, E. O.

1986-01-01

An overview and synthesis is given of recent developments that have occurred in the areas of Forbush decreases, geomagnetic and atmospheric effects, and cosmogenic nuclides. Experimental evidence has been found for substantial differences in the effects of the various types of interplanetary perturbations on cosmic rays, and for a dependence of these effects on the three-dimensional configuration of the interplanetary medium. In order to fully understand and to be able to simulate the solar cosmic ray particle access to the polar regions of the earth we need accurate models of the magnetospheric magnetic field. These models must include all major magnetospheric current systems (in particular the field aligned currents), and they should represent magnetically quiet time periods as well as different levels of geomagnetic activity. In the evolution of magnetospheric magnetic field models, cosmic ray and magnetospheric physicists should work closely together since cosmic ray measurements are a powerful additional tool in the study of the perturbed magnetosphere. In the field of cosmogenic nuclides, finally, exciting new results and developments follow in rapid succession. Thanks to new techniques and new isotopes the analysis of cosmic ray history has entered into a new dimension.

Estimating Fallout Building Attributes from Architectural Features and Global Earthquake Model (GEM) Building Descriptions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dillon, Michael B.; Kane, Staci R.

A nuclear explosion has the potential to injure or kill tens to hundreds of thousands (or more) of people through exposure to fallout (external gamma) radiation. Existing buildings can protect their occupants (reducing fallout radiation exposures) by placing material and distance between fallout particles and individuals indoors. Prior efforts have determined an initial set of building attributes suitable to reasonably assess a given building’s protection against fallout radiation. The current work provides methods to determine the quantitative values for these attributes from (a) common architectural features and data and (b) buildings described using the Global Earthquake Model (GEM) taxonomy. Thesemore » methods will be used to improve estimates of fallout protection for operational US Department of Defense (DoD) and US Department of Energy (DOE) consequence assessment models.« less

Cancer mortality in residents of the terrain-shielded area exposed to fallout from the Nagasaki atomic bombing.

PubMed

Yokota, Kenichi; Mine, Mariko; Kondo, Hisayoshi; Matsuda, Naoki; Shibata, Yoshisada; Takamura, Noboru

2018-01-01

The health effects of radiation exposure from the atomic bomb fallout remain unclear. The objective of the present study is to elucidate the association between low-dose radiation exposure from the atomic bomb fallout and cancer mortality among Nagasaki atomic bomb survivors. Of 77 884 members in the Nagasaki University Atomic Bomb Survivors Cohort, 610 residents in the terrain-shielded area with fallout were selected for this analysis; 1443 residents in the terrain-shielded area without fallout were selected as a control group; and 3194 residents in the direct exposure area were also selected for study. Fifty-two deaths due to cancer in the terrain-shielded fallout area were observed during the follow-up period from 1 January 1970 to 31 December 2012. The hazard ratio for cancer mortality in the terrain-shielded fallout area was 0.90 (95% confidence interval: 0.65-1.24). No increase in the risk of cancer mortality was observed, probably because the dose of the radiation exposure was low for residents in the terrain-shielded fallout areas of the Nagasaki atomic bomb, and also because the number of study subjects was small. © The Author 2017. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Fallout risk following a major nuclear attack on the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harvey, T.F.; Shapiro, C.S.; Wittler, R.F.

Fallout distributions are calculated for nuclear attacks on the contiguous United States. Four attack scenarios are treated, including counterforce and counterforce-countervalue attacks, for meteorological conditions associated with a typical day in summer and one in winter. The countervalue attacks contain mostly airbursts. To determine fallout effects, the population surviving the prompt effects is first calculated. For the prompt effects, a 'conflagration-type' model is used. The counterforce attack produces about 8 million prompt deaths, and the counterforce-countervalue case projects 98 million prompt deaths. Partial relocation before attack to low-risk fallout areas at least 15 km from potential strategic targets would resultmore » in a decrease in projections of deaths by tens of millions. For fallout risk calculations, only the dose received in the first 48 h (the early or local fallout) is considered. Populations are assumed to be sheltered, with a shelter protection factor profile that varies for a large urban area, a small urban area, or a rural area. With these profiles, without relocation, the fallout fatalities for all four attack scenarios are calculated to be less than one million people. This can be compared to fallout fatalities of about 10 million for a hypothetical unsheltered 'phantom' population.« less

239Pu fallout across continental Australia: Implications on 239Pu use as a soil tracer.

PubMed

Lal, R; Fifield, L K; Tims, S G; Wasson, R J

2017-11-01

At present there is a need for the development of new radioisotopes for soil erosion and sediment tracing especially as fallout 137 Cs levels become depleted. Recent studies have shown that 239 Pu can be a useful new soil erosion and sediment radioisotope tracer. 239 Pu was released in the major atmospheric nuclear weapons tests of 1950's and 1960's. However 239 Pu has a half-life of 24110 years and more than 99% of this isotope is still present in the environment today. In contrast 137 Cs with a half-life of 30.07 year has decayed to <35% of initially deposited activities and this isotope will become increasingly difficult to measure in the coming decades especially in the southern hemisphere, which received only about a third of the total global fallout from the atmospheric tests (UNSCEAR, 2000). In this study an assessment of the 239 Pu fallout in Australia was carried out from comparison of measured 239 Pu inventories with expected 239 Pu inventories from fallout models. 239 Pu inventories were also compared with rainfall and measured 240 Pu/ 239 Pu ratios across Australia. 239 Pu fallout inventories ranged from 430 to 1461 μB/cm 2 . Central Australia, with fallout 107% in excess of expected values, seems to be strongly impacted by local fallout deposition. In comparison other sites typically show 5-40% variation between expected and measured fallout values. The fallout inventories were found to weakly correlate (using power functions, y = ax b ) with rainfall with r 2  = 0.50 across the southern catchments (25-40°S latitude band). Across the northern catchments (10-25°S latitude band) fallout showed greater variability with rainfall with r 2  = 0.24. Central Australia and Alice Springs which seem to be strongly impacted by local fallout are excluded from the rainfall correlation data (with these sites included r 2  = 0.08 and r 2  < 0.01 respectively). 240 Pu/ 239 Pu atom ratios range from 0.045 to 0.197, with averages of 0.139(0.017), 0.111(0.052) and 0.160(0.027) in the 10-20°S, 20-30°S and 30-40°S latitude bands respectively. The 240 Pu/ 239 Pu atom ratios in Central Australia (0.069) likely represent fallout from the Australian tests which also have low 240 Pu/ 239 Pu atom ratios i.e., Maralinga (0.113) and Montebello (0.045). The average ratios in the 20-30°S and 30-40° bands are closer to the global average (0.139 and 0.177 respectively when not including the close-in fallout data from the nuclear test sites) if the Australian test sites and Central Australian sites are neglected as they clearly represent the effects of close in fallout. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simplified data assimilation for simulating wet deposition distribution of radioactive materials in FDNPP accident

NASA Astrophysics Data System (ADS)

Saya, A.; Yoshikane, T.; Chang, E. C.; Yoshimura, K.

2015-12-01

Due to the massive earthquakes and tsunami on March 11th 2011 in Eastern Japan, Fukushima Daiichi Nuclear Power Plant (FDNPP) was severely damaged. Radioactive materials were released and spread out by atmospheric advection-diffusion. Especially on March 21 - 23th when precipitation was observed, "hotspot" where the high concentration was detected locally. This area was formed in the metropolitan area in Kanto region. Thus, pollution at water treatment plants because of the deposition became a concern. Therefore, the reliable information of the hotspot is expected. Currently, atmospheric transport simulations by numerical models are developed for reproduction of the distribution. However, there are some uncertainties in the simulations. In the case of hotspot, accuracy of simulated precipitation have to be well considered because the hotspot seemed to be formed by wet deposition. We modified the stable isotope mode of Regional Spectral Model (IsoRSM) to enable to simulate the transport of the radioactive tracers, namely 131I and 137Cs, by including the dry and wet deposition processes. As the simplified data assimilation, simulated precipitation was replaced with Radar-AMeDAS precipitation data (RAP). RAP was assimilated in the post-process, after running simulations, to redistribute wet deposition of 137Cs. The ratio of 137Cs deposited from the cumulative vertical column with precipitation in the domain was not changed, however its pattern was redistributed corresponding with RAP and simulated concentration. As a result, the redistributed wet deposition was within factor 10 to 2 compared with the fallout data in Kanto region, and further data assimilation would be contributed. In addition, we found that due to the arrival time of the plume in the morning on 21st and the border time of daily observation data of fallout, validation result might be worse even though hourly distributions are well simulated.

Comparing Time-Dependent Geomagnetic and Atmospheric Effects on Cosmogenic Nuclide Production Rate Scaling

NASA Astrophysics Data System (ADS)

Lifton, N. A.

2014-12-01

A recently published cosmogenic nuclide production rate scaling model based on analytical fits to Monte Carlo simulations of atmospheric cosmic ray flux spectra (both of which agree well with measured spectra) (Lifton et al., 2014, Earth Planet. Sci. Lett. 386, 149-160: termed the LSD model) provides two main advantages over previous scaling models: identification and quantification of potential sources of bias in the earlier models, and the ability to generate nuclide-specific scaling factors easily for a wide range of input parameters. The new model also provides a flexible framework for exploring the implications of advances in model inputs. In this work, the scaling implications of two recent time-dependent spherical harmonic geomagnetic models spanning the Holocene will be explored. Korte and Constable (2011, Phys. Earth Planet. Int. 188, 247-259) and Korte et al. (2011, Earth Planet. Sci. Lett. 312, 497-505) recently updated earlier spherical harmonic paleomagnetic models used by Lifton et al. (2014) with paleomagnetic measurements from sediment cores in addition to archeomagnetic and volcanic data. These updated models offer improved accuracy over the previous versions, in part to due to increased temporal and spatial data coverage. With the new models as input, trajectory-traced estimates of effective vertical cutoff rigidity (RC- the standard method for ordering cosmic ray data) yield significantly different time-integrated scaling predictions when compared to the earlier models. These results will be compared to scaling predictions using another recent time-dependent spherical harmonic model of the Holocene geomagnetic field by Pavón-Carrasco et al. (2014, Earth Planet. Sci. Lett. 388, 98-109), based solely on archeomagnetic and volcanic paleomagnetic data, but extending to 14 ka. In addition, the potential effects of time-dependent atmospheric models on LSD scaling predictions will be presented. Given the typical dominance of altitudinal over latitudinal scaling effects on cosmogenic nuclide production, incorporating transient global simulations of atmospheric structure (e.g., Liu et al., 2009, Science 325, 310-314) into scaling frameworks may contribute to improved understanding of long-term production rate variations.

Uncertainties in the production of p nuclides in thermonuclear supernovae determined by Monte Carlo variations

NASA Astrophysics Data System (ADS)

Nishimura, N.; Rauscher, T.; Hirschi, R.; Murphy, A. St J.; Cescutti, G.; Travaglio, C.

2018-03-01

Thermonuclear supernovae originating from the explosion of a white dwarf accreting mass from a companion star have been suggested as a site for the production of p nuclides. Such nuclei are produced during the explosion, in layers enriched with seed nuclei coming from prior strong s processing. These seeds are transformed into proton-richer isotopes mainly by photodisintegration reactions. Several thousand trajectories from a 2D explosion model were used in a Monte Carlo approach. Temperature-dependent uncertainties were assigned individually to thousands of rates varied simultaneously in post-processing in an extended nuclear reaction network. The uncertainties in the final nuclear abundances originating from uncertainties in the astrophysical reaction rates were determined. In addition to the 35 classical p nuclides, abundance uncertainties were also determined for the radioactive nuclides 92Nb, 97, 98Tc, 146Sm, and for the abundance ratios Y(92Mo)/Y(94Mo), Y(92Nb)/Y(92Mo), Y(97Tc)/Y(98Ru), Y(98Tc)/Y(98Ru), and Y(146Sm)/Y(144Sm), important for Galactic Chemical Evolution studies. Uncertainties found were generally lower than a factor of 2, although most nucleosynthesis flows mainly involve predicted rates with larger uncertainties. The main contribution to the total uncertainties comes from a group of trajectories with high peak density originating from the interior of the exploding white dwarf. The distinction between low-density and high-density trajectories allows more general conclusions to be drawn, also applicable to other simulations of white dwarf explosions.

Development of a methodology to evaluate material accountability in pyroprocess

NASA Astrophysics Data System (ADS)

Woo, Seungmin

This study investigates the effect of the non-uniform nuclide composition in spent fuel on material accountancy in the pyroprocess. High-fidelity depletion simulations are performed using the Monte Carlo code SERPENT in order to determine nuclide composition as a function of axial and radial position within fuel rods and assemblies, and burnup. For improved accuracy, the simulations use short burnups step (25 days or less), Xe-equilibrium treatment (to avoid oscillations over burnup steps), axial moderator temperature distribution, and 30 axial meshes. Analytical solutions of the simplified depletion equations are built to understand the axial non-uniformity of nuclide composition in spent fuel. The cosine shape of axial neutron flux distribution dominates the axial non-uniformity of the nuclide composition. Combined cross sections and time also generate axial non-uniformity, as the exponential term in the analytical solution consists of the neutron flux, cross section and time. The axial concentration distribution for a nuclide having the small cross section gets steeper than that for another nuclide having the great cross section because the axial flux is weighted by the cross section in the exponential term in the analytical solution. Similarly, the non-uniformity becomes flatter as increasing burnup, because the time term in the exponential increases. Based on the developed numerical recipes and decoupling of the results between the axial distributions and the predetermined representative radial distributions by matching the axial height, the axial and radial composition distributions for representative spent nuclear fuel assemblies, the Type-0, -1, and -2 assemblies after 1, 2, and 3 depletion cycles, is obtained. These data are appropriately modified to depict processing for materials in the head-end process of pyroprocess that is chopping, voloxidation and granulation. The expectation and standard deviation of the Pu-to-244Cm-ratio by the single granule sampling calculated by the central limit theorem and the Geary-Hinkley transformation. Then, the uncertainty propagation through the key-pyroprocess is conducted to analyze the Material Unaccounted For (MUF), which is a random variable defined as a receipt minus a shipment of a process, in the system. The random variable, LOPu, is defined for evaluating the non-detection probability at each Key Measurement Point (KMP) as the original Pu mass minus the Pu mass after a missing scenario. A number of assemblies for the LOPu to be 8 kg is considered in this calculation. The probability of detection for the 8 kg LOPu is evaluated with respect the size of granule and powder using the event tree analysis and the hypothesis testing method. We can observe there are possible cases showing the probability of detection for the 8 kg LOPu less than 95%. In order to enhance the detection rate, a new Material Balance Area (MBA) model is defined for the key-pyroprocess. The probabilities of detection for all spent fuel types based on the new MBA model are greater than 99%. Furthermore, it is observed that the probability of detection significantly increases by increasing granule sample sizes to evaluate the Pu-to-244Cm-ratio before the key-pyroprocess. Based on these observations, even though the Pu material accountability in pyroprocess is affected by the non-uniformity of nuclide composition when the Pu-to-244Cm-ratio method is being applied, that is surmounted by decreasing the uncertainty of measured ratio by increasing sample sizes and modifying the MBAs and KMPs. (Abstract shortened by ProQuest.).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soti, Zsolt; Magill, Joseph; Pfennig, Gerda

Following the success of the 8. Edition of the Karlsruhe Nuclide Chart 2012, a new edition is planned for 2015. Since the 2012 edition, more than 100 nuclides have been discovered and about 1400 nuclides have been updated. In summary, the new 9. edition contains decay and radiation data on approximately 3230 ground state nuclides and 740 isomers from 118 chemical elements. The accompanying booklet provides a detailed explanation of the nuclide box structure used in the Chart. An expanded section contains many additional nuclide decay schemes to aid the user to interpret the highly condensed information in the nuclidemore » boxes. The booklet contains - in addition to the latest values of the physical constants and physical properties - a periodic table of the elements, tables of new and updated nuclides, and a difference chart showing the main changes in the Chart graphically. (authors)« less

Cosmic-Ray Nucleosynthesis of p-nuclei: Yields and Routes

NASA Astrophysics Data System (ADS)

Kusakabe, Motohiko; Mathews, Grant J.

2018-02-01

We investigate the cosmic-ray nucleosynthesis (CRN) of proton-rich stable nuclides (p-nuclides). We calculate the cosmic-ray (CR) energy spectra of heavy nuclides with mass number A=[74,209], taking into account the detailed nuclear spallation, decay, energy loss, and escape from the Galaxy during the CR propagation. We adopt the latest semiempirical formula SPACS for the spallation cross sections and the latest data on nuclear decay. Effective electron-capture decay rates are calculated using the proper cross sections for recombination and ionization in the whole CR energy region. Calculated CR spectral shapes vary for different nuclides. Abundances of proton-rich unstable nuclides increase in CRs with increasing energy relative to those of other nuclides. Yields of the primary and secondary spallation processes and differential yields from respective seed nuclides are calculated. We find that the CR energy region of ≤slant { \\mathcal O }(100) MeV/nucleon predominantly contributes to the total yields. The atomic cross sections in the low-energy range adopted in this study are then necessary. Effects of CRN on the Galactic chemical evolution of p-nuclides are calculated. Important seed nuclides are identified for respective p-nuclides. The contribution of CRN is significant for 180m Ta, accounting for about 20% of the solar abundance. About 87% of the 180m Ta CRN yield can be attributed to the primary process. The most important production routes are reactions of 181Ta, 180Hf, and 182W. CRN yields of other p-nuclides are typically about { \\mathcal O }(10‑4–10‑2) of solar abundances.

The status of the AMS system at MALT in its 20th year

NASA Astrophysics Data System (ADS)

Matsuzaki, Hiroyuki; Nakano, Chuichiro; Tsuchiya, Yoko S.; Ito, Seiji; Morita, Akira; Kusuno, Haruka; Miyake, Yasuto; Honda, Maki; Bautista VII, Angel T.; Kawamoto, Marina; Tokuyama, Hironori

2015-10-01

MALT (Micro Analysis Laboratory, Tandem accelerator, The University of Tokyo) was designed for a 'highly sensitive and precise elemental and isotopic microanalysis system' using an ion-beam generated by a Pelletron™ 5UD tandem accelerator. Currently, a multi-nuclide AMS (10Be, 14C, 26Al, 36Cl, 129I) system is available and shows good performance in both precision and sensitivity, and the accelerator serves for PIXE, NRA, ERDA/RBS measurements as well. The total operation time of the accelerator has been over 95,000 hours since the start of MALT, 20 years ago. After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, many projects related to 129I have been conducted. The retrospective reconstruction of the 131I distribution at the accident from 129I is one of the most important missions for dose evaluation of the residents. The accident-derived 129I is also quite useful as a tracer for the general iodine dynamics in the environment. As a new tool for environmental assessment related to nuclear activity, including the global fallout from past atmospheric nuclear bomb testing, effects from the spent fuel reprocessing plant, and nuclear accidents such as Chernobyl and FDNPP, a 236U-AMS system is now under development.

Restoration of water environment contaminated by radioactive cesium released from Fukushima Daiichi NPP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeshita, K.; Takahashi, H.; Jinbo, Y.

2013-07-01

In the Fukushima Daiichi NPP Accident, large amounts of volatile radioactive nuclides, such as {sup 131}I, {sup 134}Cs and {sup 137}Cs, were released to the atmosphere and huge areas surrounding the nuclear site were contaminated by the radioactive fallout. In this study, a combined process with a hydrothermal process and a coagulation settling process was proposed for the separation of radioactive Cs from contaminated soil and sewage sludge. The coagulation settling operation uses Prussian Blue (Ferric ferrocyanide) and an inorganic coagulant. The recovery of Cs from sewage sludge sampled at Fukushima city (100.000 Bq/kg) and soil at a nearby villagemore » (55.000 Bq/kg), was tested. About 96% of Cs in the sewage sludge was removed successfully by combining simple hydrothermal decomposition and coagulation settling. However, Cs in the soil was not removed sufficiently by the combined process (Cs removal is only 56%). The hydrothermal decomposition with blasting was carried out. The Cs removal from the soil was increased to 85%. When these operations were repeated twice, the Cs recovery was over 90%. The combined process with hydrothermal blasting and coagulation settling is applicable to the removal of Cs from highly contaminated soil.« less

Coupling the Near and Far Field Models for Performance Assessment of Repositories for Spent Nuclear Fuel

NASA Astrophysics Data System (ADS)

Liu, L.; Neretnieks, I.

2006-12-01

ABSTRACT In our conceptualisation, water flows in channels in fractures in fractured rocks such as granites. In the Swedish concept for a repository for spent nuclear fuel the canisters containing the spent fuel are embedded in a buffer in holes below the floor of tunnels. The deposition holes can be intersected by fractures with channels with flowing water. The flow in individual channels is determined by the transmissivity properties of the network of the channels. The flowrate around a deposition hole and in the excavation damaged zone around the tunnels will control the rate of mass transfer of corrosive agents and of escaping nuclides. We call the carrying capacity of the solutes an equivalent flowrate. An escaping nuclide will reach the flowing water in the channel and be transported further into the channel network, mixing with water from other channels at some channel intersections and dividing into several channels at other intersection. In order to follow a nuclide from any leaking canister to the effluent points at the ground surface we have integrated our channel network model CHAN3D with our near field mass transfer model NUCTRAN. The NUCTRAN code, based on a compartment model can calculate the release of nuclides from a defective canister through different pathways into the near field of a repository from the local flowrates in the channels near the deposition hole obtained from CHAN3D. The network model CHAN3D uses observed transmissivity distributions and flowing fracture frequencies in boreholes to set up the 3-dimensional network of stochastic fractures. Deterministic fracture zones are described as such with their hydraulic, properties, sizes, locations and extensions. When available, information on fracture length distributions e.g. power law distributions and correlations between sizes and transmissivities are included in the network model. Once flowrates in all channels in the network have been calculated all equivalent flowrates for all canister positions can be calculated. The rate of transport of corrosive agents to and the releases of nuclides from any damaged canister are then calculated. For any given canister location the channel network model is then used to calculate the paths of the nuclides from the canister through the network by particle tracking. A large number of particles are released one by one from the canister and followed from one channel intersection to the next. A mixing rule is used at an intersection to decide which exit the particle takes. We mostly assume full mixing at intersections. The residence time and the ratio of flow wetted surface to flowrate along every path the particles traverse is summed. This information is sufficient to determine the residence time distribution (RTD) of the nuclides along that path also when they are subject to retardation by surface sorption and matrix diffusion. Actually this information is also sufficient to determine the RTD of arbitrary length decay chains subject to some minor (unimportant) simplifying assumptions. In this paper, we discuss in detail the coupling concept of how to integrate the near and far field models, together with the method of how to include transmissive fractures following a power law length distribution and fracture zones into CHAN3D in order to significantly decrease the computer time without loss of important features of the far field. The simulation results regarding a hypothetical repository located at the Forsmark area, Sweden, are also presented and discussed. Our study suggests that the integrated model can be used as an efficient tool to simulate the release of nuclides, including decay chains, from a repository and the transport to recipients.

Inferring the chemical form of 137Cs deposited by the Fukushima Dai-ichi Nuclear Power Plant accident by measuring (137)Cs incorporated into needle leaves and male cones of Japanese cedar trees.

PubMed

Kanasashi, Tsutomu; Takenaka, Chisato; Sugiura, Yuki

2016-05-15

We hypothesized that the water-soluble (ionic) and water-insoluble (stable) radiocesium from the initial fallout of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident was distributed in various proportions in the surrounding areas and that this distribution was reflected in the trees that suffered deposition from the initial fallout. This study attempted to evaluate local variations in the chemical form of (137)Cs derived from the initial fallout of the FDNPP accident and whether its chemical form affected the radiocesium concentration in the tissues currently growing in trees, even after the initial fallout ceased. For these estimations, the ratio between the (137)Cs concentration in Cryptomeria japonica needle leaves in the tree crown, which existed before the FDNPP accident and subsequently directly exposed to the initial fallout ((137)Cs pre-accident N), and the amount of (137)Cs in the initial fallout itself ((137)Cs fallout) was determined ((137)Cs pre-accident N/(137)Cs fallout) at 66 sites. In addition, the (137)Cs ratios between the male cones produced in 2012 ((137)Cs male cone) and needle leaves that had elongated in the spring of 2011 ((137)Cs 2011N) was determined at 82 sites ((137)Cs male cone/(137) Cs 2011N). Most of the sites with lower (137)Cs pre-accident N /(137)Cs fallout ratios were distributed in eastern Fukushima, relatively close to the Pacific Ocean coastline. Lower (137)Cs pre-accident N/(137)Cs fallout and higher (137)Cs malecone/(137)Cs 2011N were found to be associated with higher proportions of (137)Cs in ionic forms. These observations are consistent with the hypothesis, and likely reflect regional variations in the chemical form of the deposited radiocesium. Copyright © 2016 Elsevier B.V. All rights reserved.

Monitoring distant fallout: the role of the Atomic Energy Commission Health and Safety Laboratory during the Pacific tests, with special attention to the events following BRAVO.

PubMed

Eisenbud, M

1997-07-01

The fallout from test BRAVO in March 1954 has had scientific, political, and social implications that have continued for more than 40 years. The test resulted in serious injury to the people of the Marshall Islands and 23 men on a nearby Japanese fishing boat. Prior to BRAVO there was insufficient appreciation of the dangers of fallout to people living downwind from surface or near-surface explosions of megaton weapons. In the absence of sufficient preplanning for fallout monitoring beyond the test-sites of earlier smaller yield tests, and as a result of the concern of the photographic film manufacturers, the Atomic Energy Commission Health and Safety Laboratory, now the Department of Energy Environmental Measurements Laboratory, was requested to develop a program of fallout surveillance. Beginning with Operation IVY in 1952, these surveys included aerial monitoring of the islands of the mid and western Pacific, as well as establishment of fallout monitoring stations in the United States and abroad. The first evidence of the post-BRAVO fallout was detected by a Atomic Energy Commission Health and Safety Laboratory instrument installed on the atoll of Rongerik, where 28 military personnel were stationed. The results of radiation surveys conducted immediately after BRAVO, as well as the reports of medical investigations, radioecological studies, and dose reconstruction that have been conducted by many laboratories over the years have been available from the beginning in unclassified form. However, from the time of the fallout, and continuing to the present, there have been many unanswered questions about what happened during the hours immediately after the fallout was reported. No formal investigation of the circumstances of the fallout was ever conducted, and there were serious misrepresentations of the facts in the official statements made at the time.

When the dust settles: stable xenon isotope constraints on the formation of nuclear fallout.

PubMed

Cassata, W S; Prussin, S G; Knight, K B; Hutcheon, I D; Isselhardt, B H; Renne, P R

2014-11-01

Nuclear weapons represent one of the most immediate threats of mass destruction. In the event that a procured or developed nuclear weapon is detonated in a populated metropolitan area, timely and accurate nuclear forensic analysis and fallout modeling would be needed to support attribution efforts and hazard assessments. Here we demonstrate that fissiogenic xenon isotopes retained in radioactive fallout generated by a nuclear explosion provide unique constraints on (1) the timescale of fallout formation, (2) chemical fractionation that occurs when fission products and nuclear fuel are incorporated into fallout, and (3) the speciation of fission products in the fireball. Our data suggest that, in near surface nuclear tests, the presence of a significant quantity of metal in a device assembly, combined with a short time allowed for mixing with the ambient atmosphere (seconds), may prevent complete oxidation of fission products prior to their incorporation into fallout. Xenon isotopes thus provide a window into the chemical composition of the fireball in the seconds that follow a nuclear explosion, thereby improving our understanding of the physical and thermo-chemical conditions under which fallout forms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Search for unbound nuclides and beam/fragment optics with the MoNA/LISA segmented target at NSCL

NASA Astrophysics Data System (ADS)

Gueye, Paul; Frank, Nathan; Thoennessen, Michael; Redpath, Thomas; MoNA Collaboration

2017-09-01

A multi-layered Si/Be segmented target consisting of three 700 mg/cm2 thick Be9 slabs and four 140 microns Si detectors was used by the MoNA Collaboration at the National Superconducting Cyclotron Laboratory of Michigan State University to study the O26 lifetime. This target provides unprecedented information on the incident beams and fragments (energy loss and position), thus allowing for better determination of the incident and outgoing energies and momenta of the detected particles compare to previous experiments conducted at this facility. With the availability of a newly developed Geant4 Monte Carlo simulation of the full N2 vault, we will present and discuss the performances of this target. Search for unbound nuclides and beam/fragment optics with the MoNA/LISA segmented target at NSCL.

Fallout from Nuclear Tests.

ERIC Educational Resources Information Center

Comar, C. L.

This booklet, in the series "Understanding the Atom," summarizes the important findings on radioactive fallout for which there is substantial scientific agreement, indicates the areas of disagreement, and lists some answered questions. Sources of fallout, its local and worldwide effects (including movement in the atmosphers), the…

Fallout sup 131 I in western Nevada cattle thyroid glands: 1962-early 1969

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blincoe, C.; Bohman, V.R.

1991-10-01

There has been continuing interest in historical fallout data. The authors have previously published data concerning the concentrations of fallout radioactive {sup 131}I in the thyroid glands of cattle from the Nevada Test Site and from commercial slaughter cattle. These data showed that bovine thyroid {sup 131}I was an effective monitor of both local and worldwide fresh nuclear fallout. This paper extends the data on commercial slaughter cattle from western Nevada through early 1969.

Implications of Atmospheric Test Fallout Data for Nuclear Winter.

NASA Astrophysics Data System (ADS)

Baker, George Harold, III

1987-09-01

Atmospheric test fallout data have been used to determine admissable dust particle size distributions for nuclear winter studies. The research was originally motivated by extreme differences noted in the magnitude and longevity of dust effects predicted by particle size distributions routinely used in fallout predictions versus those used for nuclear winter studies. Three different sets of historical data have been analyzed: (1) Stratospheric burden of Strontium -90 and Tungsten-185, 1954-1967 (92 contributing events); (2) Continental U.S. Strontium-90 fallout through 1958 (75 contributing events); (3) Local Fallout from selected Nevada tests (16 events). The contribution of dust to possible long term climate effects following a nuclear exchange depends strongly on the particle size distribution. The distribution affects both the atmospheric residence time and optical depth. One dimensional models of stratospheric/tropospheric fallout removal were developed and used to identify optimum particle distributions. Results indicate that particle distributions which properly predict bulk stratospheric activity transfer tend to be somewhat smaller than number size distributions used in initial nuclear winter studies. In addition, both ^{90}Sr and ^ {185}W fallout behavior is better predicted by the lognormal distribution function than the prevalent power law hybrid function. It is shown that the power law behavior of particle samples may well be an aberration of gravitational cloud stratification. Results support the possible existence of two independent particle size distributions in clouds generated by surface or near surface bursts. One distribution governs late time stratospheric fallout, the other governs early time fallout. A bimodal lognormal distribution is proposed to describe the cloud particle population. The distribution predicts higher initial sunlight attenuation and lower late time attenuation than the power law hybrid function used in initial nuclear winter studies.

A simplified 137Cs transport model for estimating erosion rates in undisturbed soil.

PubMed

Zhang, Xinbao; Long, Yi; He, Xiubin; Fu, Jiexiong; Zhang, Yunqi

2008-08-01

(137)Cs is an artificial radionuclide with a half-life of 30.12 years which released into the environment as a result of atmospheric testing of thermo-nuclear weapons primarily during the period of 1950s-1970s with the maximum rate of (137)Cs fallout from atmosphere in 1963. (137)Cs fallout is strongly and rapidly adsorbed by fine particles in the surface horizons of the soil, when it falls down on the ground mostly with precipitation. Its subsequent redistribution is associated with movements of the soil or sediment particles. The (137)Cs nuclide tracing technique has been used for assessment of soil losses for both undisturbed and cultivated soils. For undisturbed soils, a simple profile-shape model was developed in 1990 to describe the (137)Cs depth distribution in profile, where the maximum (137)Cs occurs in the surface horizon and it exponentially decreases with depth. The model implied that the total (137)Cs fallout amount deposited on the earth surface in 1963 and the (137)Cs profile shape has not changed with time. The model has been widely used for assessment of soil losses on undisturbed land. However, temporal variations of (137)Cs depth distribution in undisturbed soils after its deposition on the ground due to downward transport processes are not considered in the previous simple profile-shape model. Thus, the soil losses are overestimated by the model. On the base of the erosion assessment model developed by Walling, D.E., He, Q. [1999. Improved models for estimating soil erosion rates from cesium-137 measurements. Journal of Environmental Quality 28, 611-622], we discuss the (137)Cs transport process in the eroded soil profile and make some simplification to the model, develop a method to estimate the soil erosion rate more expediently. To compare the soil erosion rates calculated by the simple profile-shape model and the simple transport model, the soil losses related to different (137)Cs loss proportions of the reference inventory at the Kaixian site of the Three Gorge Region, China are estimated by the two models. The over-estimation of the soil loss by using the previous simple profile-shape model obviously increases with the time period from the sampling year to the year of 1963 and (137)Cs loss proportion of the reference inventory. As to 20-80% of (137)Cs loss proportions of the reference inventory at the Kaixian site in 2004, the annual soil loss depths estimated by the new simplified transport process model are only 57.90-56.24% of the values estimated by the previous model.

ATTENUATION OF COBALT-60 RADIATION FROM A SOURCE DISTRIBUTED AROUND A CONCRETE BLOCKHOUSE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Batter, J.F.; Starbird, A.W.

1961-06-15

Two radiation-shielding experiments were performed upon a simple blockhouse structure. The blockhouse was exposed to a simulated fallout field, and the radiation penetrating the structure was measured. The radiation field was produced by circulating a sealed cobalt-60 source through polyethylene tubing predistributed over an octant centered on the test building. Experimental details are described and results tabulated. (auth)

Laboratory Study of Airborne Fallout Particles and Their Time Distribution.

ERIC Educational Resources Information Center

Smith, H. A., Jr.; And Others

1979-01-01

Samples of filtered airborne particulate, collected daily for the first month after the September 18, 1977 Chinese nuclear detonation, showed fourteen fission products. Fluctuations in the daily fallout activity levels suggested a global fallout orbit time of approximately twenty days. (Author/BB)

Radioactive fallout projections and arms control agreements: INF (Intermediate-range Nuclear Forces) and START (Strategic Arms Reduction Treaty)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shapiro, C.S.

1988-02-01

Projections of levels of radioactive fallout from a nuclear war are sensitive to assumptions about the structure of the nuclear stockpiles as well as the assumed scenarios for a nuclear war. Recent arms control proposals would change these parameters. This paper examines the implications of the proposed (Intermediate-range Nuclear Forces) INF treaty and (Strategic Arms Reduction Treaty) START on fallout projections from a major nuclear war. We conclude that the INF reductions are likely to have negligible effects on estimates of global and local fallout, whereas the START reductions could result in reductions in estimates of local fallout that rangemore » from significant to dramatic, depending upon the nature of the reduced strategic forces. Should a major war occur, projections of total fatalities from direct effects of blast, thermal radiation, a nd fallout, and the phenomenon known as nuclear winter, would not be significantly affected by INF and START initiatives as now drafted. 14 refs.« less

Comparison of actinide production in traveling wave and pressurized water reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osborne, A.G.; Smith, T.A.; Deinert, M.R.

The geopolitical problems associated with civilian nuclear energy production arise in part from the accumulation of transuranics in spent nuclear fuel. A traveling wave reactor is a type of breed-burn reactor that could, if feasible, reduce the overall production of transuranics. In one possible configuration, a cylinder of natural or depleted uranium would be subjected to a fast neutron flux at one end. The neutrons would transmute the uranium, producing plutonium and higher actinides. Under the right conditions, the reactor could become critical, at which point a self-stabilizing fission wave would form and propagate down the length of the reactormore » cylinder. The neutrons from the fission wave would burn the fissile nuclides and transmute uranium ahead of the wave to produce additional fuel. Fission waves in uranium are driven largely by the production and fission of {sup 239}Pu. Simulations have shown that the fuel burnup can reach values greater than 400 MWd/kgIHM, before fission products poison the reaction. In this work we compare the production of plutonium and minor actinides produced in a fission wave to that of a UOX fueled light water reactor, both on an energy normalized basis. The nuclide concentrations in the spent traveling wave reactor fuel are computed using a one-group diffusion model and are verified using Monte Carlo simulations. In the case of the pressurized water reactor, a multi-group collision probability model is used to generate the nuclide quantities. We find that the traveling wave reactor produces about 0.187 g/MWd/kgIHM of transuranics compared to 0.413 g/MWd/kgIHM for a pressurized water reactor running fuel enriched to 4.95 % and burned to 50 MWd/kgIHM. (authors)« less

Dual-core mass-balance approach for evaluating mercury and210Pb atmospheric fallout and focusing to lakes

USGS Publications Warehouse

Van Metre, P.C.; Fuller, C.C.

2009-01-01

Determining atmospheric deposition rates of mercury and other contaminants using lake sediment cores requires a quantitative understanding of sediment focusing. Here we present a novel approach that solves mass-balance equations for two cores algebraically to estimate contaminant contributions to sediment from direct atmospheric fallout and from watershed and in-lake focusing. The model is applied to excess 210Pb and Hg in cores from Hobbs Lake, a high-altitude lake in Wyoming. Model results for excess 210Pb are consistent with estimates of fallout and focusing factors computed using excess 210Pb burdens in lake cores and soil cores from the watershed and model results for Hg fallout are consistent with fallout estimated using the soil-core-based 210Pb focusing factors. The lake cores indicate small increases in mercury deposition beginning in the late 1800s and large increases after 1940, with the maximum at the tops of the cores of 16-20 ??g/m 2year. These results suggest that global Hg emissions and possibly regional emissions in the western United States are affecting the north-central Rocky Mountains. Hg fallout estimates are generally consistent with fallout reported from an ice core from the nearby Upper Fremont Glacier, but with several notable differences. The model might not work for lakes with complex geometries and multiple sediment inputs, but for lakes with simple geometries, like Hobbs, it can provide a quantitative approach for evaluating sediment focusing and estimating contaminant fallout.

A New Approach for the Determination of Dose Rate and Radioactivity for Detected Gamma Nuclides Using an Environmental Radiation Monitor Based on an NaI(Tl) Detector.

PubMed

Ji, Young-Yong; Kim, Chang-Jong; Lim, Kyo-Sun; Lee, Wanno; Chang, Hyon-Sock; Chung, Kun Ho

2017-10-01

To expand the application of dose rate spectroscopy to the environment, the method using an environmental radiation monitor (ERM) based on a 3' × 3' NaI(Tl) detector was used to perform real-time monitoring of the dose rate and radioactivity for detected gamma nuclides in the ground around an ERM. Full-energy absorption peaks in the energy spectrum for dose rate were first identified to calculate the individual dose rates of Bi, Ac, Tl, and K distributed in the ground through interference correction because of the finite energy resolution of the NaI(Tl) detector used in an ERM. The radioactivity of the four natural radionuclides was then calculated from the in situ calibration factor-that is, the dose rate per unit curie-of the used ERM for the geometry of the ground in infinite half-space, which was theoretically estimated by Monte Carlo simulation. By an intercomparison using a portable HPGe and samples taken from the ground around an ERM, this method to calculate the dose rate and radioactivity of four nuclides using an ERM was experimentally verified and finally applied to remotely monitor them in real-time in the area in which the ERM had been installed.

Federal Guidance Report No. 6: Revised Fallout Estimates for 1964-1965 and Verification of the 1963 Predictions

EPA Pesticide Factsheets

The purposes of this report is to compare, make more precise estimates about the predictions made as to the levels of fallout, and evaluate the validity of the prediction procedures when they are applied to a changing fallout situation.

DUAL USE OF SCHOOL FALLOUT SHELTER SPACE.

ERIC Educational Resources Information Center

SAYERS, JOHN

THIS REPORT DISCUSSES CONSIDERATIONS IN THE USE OF FALLOUT SHELTER SPACE FOR NORMAL SCHOOL ACTIVITIES, INCLUDING THE REQUIREMENTS FOR FALLOUT SHELTERS AND PROBLEMS RELATED TO WINDOWLESS ROOMS. THE PRESENT LACK OF INFORMATION ABOUT PSYCHOLOGICAL PROBLEMS RELATED TO WINDOWLESS ROOMS IS MENTIONED. THE BEST USES FOR WINDOWLESS SPACE ARE NOTED--(1)…

Federal Guidance Report No. 4: Estimates and Evaluation of Fallout in the United States from Nuclear Weapons Testing Conducted Through 1962

EPA Pesticide Factsheets

This Federal Radiation Council report includes a full study and analysis of fallout expected in 1963 from nuclear testing that occurred in the past. This report covers fallout expected from Soviet and United States tests through 1962.

Redistribution of fallout radionuclides in Enewetak Atoll lagoon sediments by callianassid bioturbation.

PubMed

McMurtry, G M; Schneider, R C; Colin, P L; Buddemeier, R W; Suchanek, T H

The lagoon sediments of Enewetak Atoll in the Marshall Islands contain a large selection of fallout radionuclides as a result of 43 nuclear weapon tests conducted there between 1948 and 1958. Studies of the burial of fallout radionuclides have been conducted on the islands and in several of the large craters, but studies of their vertical distribution have been limited to about the upper 20 cm of the lagoon sediments. We have found elevated fallout radionuclide concentrations buried more deeply in the lagoon sediments and evidence of burrowing into the sediment by several species of callianassid ghost shrimp (Crustacea: Thalassinidea) which has displaced highly radioactive sediment. The burrowing activities of callianassids, which are ubiquitous on the lagoon floor, facilitate radionuclide redistribution and complicate the fallout radionuclide inventory of the lagoon.

The scheme for evaluation of isotopic composition of fast reactor core in closed nuclear fuel cycle

NASA Astrophysics Data System (ADS)

Saldikov, I. S.; Ternovykh, M. Yu; Fomichenko, P. A.; Gerasimov, A. S.

2017-01-01

The PRORYV (i.e. «Breakthrough» in Russian) project is currently under development. Within the framework of this project, fast reactors BN-1200 and BREST-OD-300 should be built to, inter alia, demonstrate possibility of the closed nuclear fuel cycle technologies with plutonium as a main source of power. Russia has a large inventory of plutonium which was accumulated in the result of reprocessing of spent fuel of thermal power reactors and conversion of nuclear weapons. This kind of plutonium will be used for development of initial fuel assemblies for fast reactors. To solve the closed nuclear fuel modeling tasks REPRORYV code was developed. It simulates the mass flow for nuclides in the closed fuel cycle. This paper presents the results of modeling of a closed nuclear fuel cycle, nuclide flows considering the influence of the uncertainty on the outcome of neutron-physical characteristics of the reactor.

Plutonium segregation in glassy aerodynamic fallout from a nuclear weapon test

DOE PAGES

Holliday, K. S.; Dierken, J. M.; Monroe, M. L.; ...

2017-01-11

Our study combines electron microscopy equipped with energy dispersive spectroscopy to probe major element composition and autoradiography to map plutonium in order to examine the spatial relationships between plutonium and fallout composition in aerodynamic glassy fallout from a nuclear weapon test. We interrogated a sample set of 48 individual fallout specimens in order to reveal that the significant chemical heterogeneity of this sample set could be described compositionally with a relatively small number of compositional endmembers. Furthermore, high concentrations of plutonium were never associated with several endmember compositions and concentrated with the so-called mafic glass endmember. Our result suggests thatmore » it is the physical characteristics of the compositional endmembers and not the chemical characteristics of the individual component elements that govern the un-burnt plutonium distribution with respect to major element composition in fallout.« less

Building Protection Against External Ionizing Fallout Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dillon, Michael B.; Homann, Steven G.

A nuclear explosion has the potential to injure or kill tens to hundreds of thousands of people through exposure to fallout (external gamma) radiation. Existing buildings can protect their occupants (reducing external radiation exposures) by placing material and distance between fallout particles and indoor individuals. This protection is not well captured in current fallout risk assessment models and so the US Department of Defense is implementing the Regional Shelter Analysis methodology to improve the ability of the Hazard Prediction and Assessment Capability (HPAC) model to account for building protection. This report supports the HPAC improvement effort by identifying a setmore » of building attributes (next page) that, when collectively specified, are sufficient to calculate reasonably accurate, i.e., within a factor of 2, fallout shelter quality estimates for many individual buildings. The set of building attributes were determined by first identifying the key physics controlling building protection from fallout radiation and then assessing which building attributes are relevant to the identified physics. This approach was evaluated by developing a screening model (PFscreen) based on the identified physics and comparing the screening model results against the set of existing independent experimental, theoretical, and modeled building protection estimates. In the interests of transparency, we have developed a benchmark dataset containing (a) most of the relevant primary experimental data published by prior generations of fallout protection scientists as well as (b) the screening model results.« less

Vertical migration of plutonium-239 + -240, americium-241 and caesium-137 fallout in a forest soil under spruce.

PubMed

Bunzl, K; Kracke, W; Schimmack, W

1992-03-01

The vertical activity distributions of fallout 238Pu, 239+240Pu, 241Am, 134Cs and 137Cs in a forest soil (Hapludult) were determined at several locations in a spruce stand separately according to their origin (global fallout or Chernobyl fallout). To determine the rate of migration of these radionuclides in each soil horizon, the observed depth profiles of the radionuclides were evaluated with a compartment model. In the top organic horizons (LOf1 and Of2), the migration rates for all radionuclides from both sources were above 0.5 cm per year. In the Oh horizon the migration rates observed for global fallout Pu, Am and Cs were similar (0.2-0.4 cm per year). Compared with Pu, however, the mobility of Am is slightly, but statistically significantly, enhanced. The highest rate in this layer was found for Chernobyl-derived radiocaesium (2 cm per year). In the layers of the mineral horizon (depth 0-2, 2-5 and 5-10 cm) the observed migration rates were very similar for global fallout Pu (0.08-0.7 cm per year) and Am (0.1-2 cm per year). In comparison, the migration rate of global fallout radiocaesium was about half in each layer. The highest rate was observed again for Chernobyl-derived radiocaesium (0.5-3 cm per year).

VERA Core Simulator methodology for pressurized water reactor cycle depletion

DOE PAGES

Kochunas, Brendan; Collins, Benjamin; Stimpson, Shane; ...

2017-01-12

This paper describes the methodology developed and implemented in the Virtual Environment for Reactor Applications Core Simulator (VERA-CS) to perform high-fidelity, pressurized water reactor (PWR), multicycle, core physics calculations. Depletion of the core with pin-resolved power and nuclide detail is a significant advance in the state of the art for reactor analysis, providing the level of detail necessary to address the problems of the U.S. Department of Energy Nuclear Reactor Simulation Hub, the Consortium for Advanced Simulation of Light Water Reactors (CASL). VERA-CS has three main components: the neutronics solver MPACT, the thermal-hydraulic (T-H) solver COBRA-TF (CTF), and the nuclidemore » transmutation solver ORIGEN. This paper focuses on MPACT and provides an overview of the resonance self-shielding methods, macroscopic-cross-section calculation, two-dimensional/one-dimensional (2-D/1-D) transport, nuclide depletion, T-H feedback, and other supporting methods representing a minimal set of the capabilities needed to simulate high-fidelity models of a commercial nuclear reactor. Results are presented from the simulation of a model of the first cycle of Watts Bar Unit 1. The simulation is within 16 parts per million boron (ppmB) reactivity for all state points compared to cycle measurements, with an average reactivity bias of <5 ppmB for the entire cycle. Comparisons to cycle 1 flux map data are also provided, and the average 2-D root-mean-square (rms) error during cycle 1 is 1.07%. To demonstrate the multicycle capability, a state point at beginning of cycle (BOC) 2 was also simulated and compared to plant data. The comparison of the cycle 2 BOC state has a reactivity difference of +3 ppmB from measurement, and the 2-D rms of the comparison in the flux maps is 1.77%. Lastly, these results provide confidence in VERA-CS’s capability to perform high-fidelity calculations for practical PWR reactor problems.« less

Cesium-137 Fallout in Indiana Soil

ERIC Educational Resources Information Center

Whitman, Richard T.

2017-01-01

Atomic weapons testing during the Cold War and accidents at nuclear power plants have resulted in the release of radioactive fallout over great distances. Little is known about levels of fallout deposited in Indiana. The reported study sampled soil in all 92 Indiana counties to determine the present level of cesium-137 from the 2 to 12 centimeter…

The grain size dependency of vesicular particle shapes strongly affects the drag of particles. First results from microtomography investigations of Campi Flegrei fallout deposits

NASA Astrophysics Data System (ADS)

Mele, Daniela; Dioguardi, Fabio

2018-03-01

Acknowledging the grain size dependency of shape is important in volcanology, in particular when dealing with tephra produced and emplaced during and after explosive volcanic eruptions. A systematic measurement of the tridimensional shape of vesicular pyroclasts of Campi Flegrei fallout deposits (Agnano-Monte Spina, Astroni 6 and Averno 2 eruptions) varying in size from 8.00 to 0.016 mm has been carried out by means of X-Ray Microtomography. Data show that particle shape changes with size, especially for juvenile vesicular clasts, since it is dependent on the distribution and size of vesicles that contour the external clast outline. Two drag laws that include sphericity in the formula were used for estimating the dependency of settling velocity on shape. Results demonstrate that it is not appropriate to assume a size-independent shape for vesicular particles, in contrast with the approach commonly employed when simulating the ash dispersion in the atmosphere.

Analysis of actinides in an ombrotrophic peat core - evidence of post-depositional migration of fallout radionuclides

NASA Astrophysics Data System (ADS)

Quinto, Francesca; Hrnecek, Erich; Krachler, Michael; Shotyk, William; Steier, Peter; Winkler, Stephan R.

2013-04-01

Plutonium (239Pu, 240Pu, 241Pu, 242Pu) and uranium (236U, 238U) isotopes were analyzed in an ombrotrophic peat core from the Black Forest, Germany, representing the last 80 years of atmospheric deposition. The reliable determination of these isotopes at ultra-trace levels was possible using ultra-clean laboratory procedures and accelerator mass spectrometry. The 240Pu/239Pu isotopic ratios are constant along the core with a mean value of 0.19 ±0.02 (N = 32). This result is consistent with the acknowledged average 240Pu/239Pu isotopic ratio from global fallout in the Northern Hemisphere. The global fallout origin of Pu is confirmed by the corresponding 241Pu/239Pu (0.0012 ±0.0005) and 242Pu/239Pu (0.004 ± 0.001) isotopic ratios. The identification of the Pu isotopic composition characteristic for global fallout in peat layers pre-dating the period of atmospheric atom bomb testing (AD 1956 - AD 1980) is a clear evidence of the migration of Pu downwards the peat profile. The maximum of global fallout derived 236U is detected in correspondence to the age/depth layer of maximum stratospheric fallout (AD 1963). This finding demonstrates that the 236U bomb peak can be successfully used as an independent chronological marker complementing the 210Pb dating of peat cores. The profiles of the global fallout derived 236U and 239Pu are compared with those of 137Cs and 241Am. As typical of ombrothrophic peat, the temporal fallout pattern of 137Cs is poorly retained. Similarly like for Pu, post-depositional migration of 241Am in peat layers preceding the era of atmospheric nuclear tests is observed.

RESULTS OF COMPUTATIONS MADE FOR DASA-USNRDL FALLOUT SYMPOSIUM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Read, R.; Wagner, L.; Moorehead, E.

1962-11-01

The regression techniques introduced by the Civil Defense Research Project for estimating fallout particle deposition coordinates, their standard ellipses, and isointensity contours have been applied to some of the homework problems assigned for the DASA-USNRDL Fallout Symposium. The results are reported and the estimates are contrasted with estimates based on the assumption that winds are invariant with time. (auth).

Equipment Level Fallout Radiation Effects Approach

DTIC Science & Technology

1989-02-10

Electromagnetic Pulse (EMP) mitigation Program to evaluate and, where possible, mitigate the effects of the nuclear attack. Fallout radiation has been identified as an environment which may effect the performance of the regional and national telecommunication system. This report presents the investigations in the network level fallout radiation methodology used to determine the effects of this environment. Alternative techniques are presented to improve the

The influence of a fire-induced convection column on radiological fallout patterns

Treesearch

A. Broido; A.W. McMasters

1959-01-01

Since no nuclear devices have been detonated by the United States under conditions leading to both mass fires and radiological fallout, a theoretical and small-scale experimental study was undertaken to see if fire-induced convection columns could significantly affect fallout patterns. Experiments were conducted in a 6- by 6-foot low-velocity wind tunnel using full-...

Linus Pauling and the scientific debate over fallout hazards.

PubMed

Jolly, J Christopher

2002-12-01

From 1954 to 1963, numerous scientists engaged in a public debate over the possible hazards from radioactive fallout from nuclear weapons testing. Nobel laureate Linus Pauling, a California Institute of Technology chemist, was one of the most prominent. His scientific papers relating to the fallout debate reveal many of the scientific, social and political issues involved in the controversy. Although the public controversy ended after the signing of the 1963 Limited Test Ban Treaty, many of the scientific questions about the possible hazards of low-level radiation remain under debate within the scientific community. Moreover, the fallout debate was a prototype of current controversies over environmental and public-health hazards.

Review of current nuclear fallout codes.

PubMed

Auxier, Jerrad P; Auxier, John D; Hall, Howard L

2017-05-01

The importance of developing a robust nuclear forensics program to combat the illicit use of nuclear material that may be used as an improvised nuclear device is widely accepted. In order to decrease the threat to public safety and improve governmental response, government agencies have developed fallout-analysis codes to predict the fallout particle size, dose, and dispersion and dispersion following a detonation. This paper will review the different codes that have been developed for predicting fallout from both chemical and nuclear weapons. This will decrease the response time required for the government to respond to the event. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Cesium-137 Fallout in Indiana Soil

NASA Astrophysics Data System (ADS)

Whitman, Richard T.

Atomic weapons testing during the Cold War and accidents at nuclear power plants have resulted in the release of radioactive fallout over great distances. Little is known about levels of fallout deposited in Indiana. The reported study sampled soil in all 92 Indiana counties to determine the present level of cesium-137 from the 2 to 12 centimeter depth from previous nuclear tests and other nuclear releases. A total of 67 samples were collected from forested areas and 25 from grasslands, both undisturbed since 1940, along with four controls from crawl spaces. Greater Cs-137 retention occurred in the forested areas at approximately a 2:1 ratio. Other parameters investigated included soil clay content, rate of rainfall, and soil pH. Each variable was examined for possible statistical correlation with Cs-137 retention. Both clay content and combined clay content/rainfall were significantly (p < 0.05) correlated with soil Cs-137 levels. The four controls showed very low values of Cs-137 indicating the movement of sub-micron sized fallout into areas considered safe from fallout. The Cs-137 data from this study will serve as a reliable baseline of Cs-137 levels in the event of a future release of fallout.

Regional Shelter Analysis Methodology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dillon, Michael B.; Dennison, Deborah; Kane, Jave

2015-08-01

The fallout from a nuclear explosion has the potential to injure or kill 100,000 or more people through exposure to external gamma (fallout) radiation. Existing buildings can reduce radiation exposure by placing material between fallout particles and exposed people. Lawrence Livermore National Laboratory was tasked with developing an operationally feasible methodology that could improve fallout casualty estimates. The methodology, called a Regional Shelter Analysis, combines the fallout protection that existing buildings provide civilian populations with the distribution of people in various locations. The Regional Shelter Analysis method allows the consideration of (a) multiple building types and locations within buildings, (b)more » country specific estimates, (c) population posture (e.g., unwarned vs. minimally warned), and (d) the time of day (e.g., night vs. day). The protection estimates can be combined with fallout predictions (or measurements) to (a) provide a more accurate assessment of exposure and injury and (b) evaluate the effectiveness of various casualty mitigation strategies. This report describes the Regional Shelter Analysis methodology, highlights key operational aspects (including demonstrating that the methodology is compatible with current tools), illustrates how to implement the methodology, and provides suggestions for future work.« less

Alimentary Tract Absorption (f1 Values) for Radionuclides in Local and Regional Fallout from Nuclear Tests

PubMed Central

Ibrahim, Shawki; Simon, Steven L; Bouville, André; Melo, Dunstana; Beck, Harold

2009-01-01

This paper presents gastrointestinal absorption fractions (f1 values) for estimating internal doses from local and regional fallout radionuclides due to nuclear tests. The choice of f1 values are based on specific circumstances of weapons test conditions and a review of reported f1 values for elements in different physical and chemical states. Special attention is given to fallout from nuclear tests conducted at the Marshall Islands. We make a distinction between the f1 values for intakes of radioactive materials immediately after deposition (acute intakes) and intakes that occur in the course of months and years after deposition, following incorporation into terrestrial and aquatic foodstuffs (chronic intakes). Multiple f1 values for different circumstances where persons are exposed to radioactive fallout (e.g. local vs. regional fallout and coral vs. continental tests) are presented when supportive information is available. In some cases, our selected f1 values are similar to those adopted by the ICRP (e.g. iodine and most actinides). However, f1 values for cesium and strontium derived from urine bioassay data of the Marshallese population are notably lower than the generic f1 values recommended by ICRP, particularly for acute intakes from local fallout (0.4 and 0.05 for Cs and Sr, respectively. The f1 values presented here form the first complete set of values relevant to realistic dose assessments for exposure to local or regional radioactive fallout. PMID:20622554

Alimentary tract absorption (f1 values) for radionuclides in local and regional fallout from nuclear tests.

PubMed

Ibrahim, Shawki A; Simon, Steven L; Bouville, André; Melo, Dunstana; Beck, Harold L

2010-08-01

This paper presents gastrointestinal absorption fractions (f1 values) for estimating internal doses from local and regional fallout radionuclides due to nuclear tests. The choice of f1 values are based on specific circumstances of weapons test conditions and a review of reported f1 values for elements in different physical and chemical states. Special attention is given to fallout from nuclear tests conducted at the Marshall Islands. We make a distinction between the f1 values for intakes of radioactive materials immediately after deposition (acute intakes) and intakes that occur in the course of months and years after deposition, following incorporation into terrestrial and aquatic foodstuffs (chronic intakes). Multiple f1 values for different circumstances where persons are exposed to radioactive fallout (e.g., local vs. regional fallout and coral vs. continental tests) are presented when supportive information is available. In some cases, our selected f1 values are similar to those adopted by the International Commission on Radiological Protection (ICRP) (e.g., iodine and most actinides). However, f1 values for cesium and strontium derived from urine bioassay data of the Marshallese population are notably lower than the generic f1 values recommended by ICRP, particularly for acute intakes from local fallout (0.4 and 0.05 for Cs and Sr, respectively). The f1 values presented here form the first complete set of values relevant to realistic dose assessments for exposure to local or regional radioactive fallout.

Nuclear Data Sheets for A = 79

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Balraj

2016-07-15

Nuclear spectroscopic information for known nuclides of mass number 79 (Ni,Cu,Zn,Ga,Ge,As,Se,Br,Kr,Rb, Sr,Y,Zr) has been evaluated and presented together with adopted energies, Jπ, and decay modes of levels in these nuclei. No data are yet available for excited states in {sup 79}Ni, {sup 79}Cu and {sup 79}Zr. The half–life of {sup 79}Se, a nuclide of importance in reactor–irradiated fuel composition has been measured by several independent groups and reported in a number of publications after 1995, and seems to be converging to a narrow margin of experimental values. These measurements were likely prompted by a recommendation made in the 1993 updatemore » of A = 79 nuclides (1993Si28), that since a 1949PaZZ report, there had been no measurement until 1993, and that based on simulation studies by 1993HeZW, the value listed in 1949PaZZ, and cited in all data tables and charts for 44 years, was quite likely in error, being too low by a factor of 10. According to conclusions in recent papers such as 2014Do20, there is still room for improvement in the measurement of this half–life, and further experiments are expected. This evaluation supersedes earlier Nuclear Data Sheets for A = 79 (2002Si13,1993Si28, 1982Si21,1975Ur03).« less

Total Cross Sections as a Surrogate for Neutron Capture: An Opportunity to Accurately Constrain (n,γ) Cross Sections for Nuclides Beyond the Reach of Direct Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koehler, Paul E.

2014-03-05

There are many (n,γ) cross sections of great interest to radiochemical diagnostics and to nuclear astrophysics which are beyond the reach of current measurement techniques, and likely to remain so for the foreseeable future. In contrast, total neutron cross sections currently are feasible for many of these nuclides and provide almost all the information needed to accurately calculate the (n,γ) cross sections via the nuclear statistical model (NSM). I demonstrate this for the case of 151Sm; NSM calculations constrained using average resonance parameters obtained from total cross section measurements made in 1975, are in excellent agreement with recent 151Sm (n,γ)more » measurements across a wide range of energy. Furthermore, I demonstrate through simulations that total cross section measurements can be made at the Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos Neutron Science Center for samples as small as 10μg. Samples of this size should be attainable for many nuclides of interest. Finally, I estimate that over half of the radionuclides identified ~20 years ago as having (n,γ) cross sections of importance to s-process nucleosynthesis studies (24/43) and radiochemical diagnostics (11/19), almost none of which have been measured, can be constrained using this technique.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kochunas, Brendan; Collins, Benjamin; Stimpson, Shane

This paper describes the methodology developed and implemented in the Virtual Environment for Reactor Applications Core Simulator (VERA-CS) to perform high-fidelity, pressurized water reactor (PWR), multicycle, core physics calculations. Depletion of the core with pin-resolved power and nuclide detail is a significant advance in the state of the art for reactor analysis, providing the level of detail necessary to address the problems of the U.S. Department of Energy Nuclear Reactor Simulation Hub, the Consortium for Advanced Simulation of Light Water Reactors (CASL). VERA-CS has three main components: the neutronics solver MPACT, the thermal-hydraulic (T-H) solver COBRA-TF (CTF), and the nuclidemore » transmutation solver ORIGEN. This paper focuses on MPACT and provides an overview of the resonance self-shielding methods, macroscopic-cross-section calculation, two-dimensional/one-dimensional (2-D/1-D) transport, nuclide depletion, T-H feedback, and other supporting methods representing a minimal set of the capabilities needed to simulate high-fidelity models of a commercial nuclear reactor. Results are presented from the simulation of a model of the first cycle of Watts Bar Unit 1. The simulation is within 16 parts per million boron (ppmB) reactivity for all state points compared to cycle measurements, with an average reactivity bias of <5 ppmB for the entire cycle. Comparisons to cycle 1 flux map data are also provided, and the average 2-D root-mean-square (rms) error during cycle 1 is 1.07%. To demonstrate the multicycle capability, a state point at beginning of cycle (BOC) 2 was also simulated and compared to plant data. The comparison of the cycle 2 BOC state has a reactivity difference of +3 ppmB from measurement, and the 2-D rms of the comparison in the flux maps is 1.77%. Lastly, these results provide confidence in VERA-CS’s capability to perform high-fidelity calculations for practical PWR reactor problems.« less

Amchitka Island, Alaska, special sampling project 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

U.S. Department of Energy, Nevada Operations Office

2000-06-28

This 1997 special sampling project represents a special radiobiological sampling effort to augment the 1996 Long-Term Hydrological Monitoring Program (LTHMP) for Amchitka Island in Alaska. Lying in the western portion of the Aleutian Islands arc, near the International Date Line, Amchitka Island is one of the southernmost islands of the Rat Island Chain. Between 1965 and 1971, the U.S. Atomic Energy Commission conducted three underground nuclear tests on Amchitka Island. In 1996, Greenpeace collected biota samples and speculated that several long-lived, man-made radionuclides detected (i.e., americium-241, plutonium-239 and -240, beryllium-7, and cesium-137) leaked into the surface environment from underground cavitiesmore » created during the testing. The nuclides of interest are detected at extremely low concentrations throughout the environment. The objectives of this special sampling project were to scientifically refute the Greenpeace conclusions that the underground cavities were leaking contaminants to the surface. This was achieved by first confirming the presence of these radionuclides in the Amchitka Island surface environment and, second, if the radionuclides were present, determining if the source is the underground cavity or worldwide fallout. This special sampling and analysis determined that the only nonfallout-related radionuclide detected was a low level of tritium from the Long Shot test, which had been previously documented. The tritium contamination is monitored and continues a decreasing trend due to radioactive decay and dilution.« less

The coprecipitation of Pu and other radionuclides with CaCO[sub 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meece, D.E.; Benninger, L.K.

1993-04-01

The record of fallout plutonium concentrations in annual bands of corals is strikingly similar to the record of atmospheric deposition of [sup 90]Sr. This similarity implies that corals may incorporate Pu from seawater with a constant partition coefficient (constant discrimination). To investigate physicochemical aspects of Pu incorporation, the following have been coprecipitated with CaCO[sub 3] (calcite and aragonite): oxidized and reduced Pu; americium, thorium, and uranium as analogs to Pu oxidation states (III, IV, VI), respectively; and [sup 210]Pb as a particle-reactive nuclide which may be incorporated by corals with constant discrimination. Americium, thorium, and lead adsorb onto both calcitemore » and aragonite, with more than 99% of the recovered activity found associated with the solids. Uranium exhibits a behavior consistent with lattice substitution. Partition coefficients for U in aragonite range from 1.8 to 9.8 and vary inversely with pH and/or rate of precipitation. The partition coefficient for U in calcite is less than 0.2 and may be as low as 0.046. Reduced Pu sorbs with 3 to 4% remaining in solution. Oxidized Pu may both sorb and coprecipitate. The coral record for Pb and U results primarily from biological, rather than physicochemical, effects; it is likely that the PU coral record also reflects biological discrimination. 50 refs., 4 figs., 5 tabs.« less

The radioactivity of seasonal dust storms in the Middle East: the May 2012 case study in Jordan.

PubMed

Hamadneh, Hamed S; Ababneh, Zaid Q; Hamasha, Khadeejeh M; Ababneh, Anas M

2015-02-01

Dust storms in the Middle East are common during spring. Some of these storms are massive and carry a large amount of dust from faraway regions, which pose health and pollution risks. The huge dust storm event occurred in early May, 2012 was investigated for its radioactive content using gamma ray spectroscopy. Dust samples were collected from Northern Jordan and it was found that the storm carried a large amount of both artificial and natural radioactivity. The average activity concentration of fallout (137)Cs was 17.0 Bq/kg which is larger than that found in soil (2.3 Bq/kg), and this enrichment is attributed to particle size effects. (7)Be which is of atmospheric origin and has a relatively short half-life, was detected in dust with relatively large activity concentrations, as it would be expected, with an average of 2860 Bq/kg, but it was not detected in soil. Despite the large activity concentration of (7)Be, dose assessment showed that it does not contribute significantly to the effective dose through inhalation. The concentrations of the primodial nuclides (40)K, (232)Th and (238)U were 547, 30.0 and 49.3 Bq/kg, respectively. With the exception of (40)K, these were comparable to what was found in soil. Copyright © 2014 Elsevier Ltd. All rights reserved.

Planning Guidance for Response to a Nuclear Detonation

DTIC Science & Technology

2009-01-16

Radiation and Fallout One of the primary outputs from a nuclear explosion is radiation . Intense radiation is...dose rates based on the quantity of visible fallout. Therefore, visible fallout may possibly be used as an indicator of a direct radiation hazard...to survivors and response workers.15 The National Council on Radiation Protection and Measurements (NCRP) has recommended 10 R/hour (R/hour) as a

Designing Shelter in New Buildings. A Manual for Architects on the Preliminary Designing of Shielding from Fallout Gamma Radiation in Normally Functioning Spaces in New Buildings.

ERIC Educational Resources Information Center

Knott, Albert

Analysis of radiation fallout prevention factors in new construction is presented with emphasis on architectural shielding principles. Numerous diagrams and charts illustrate--(1) radiation and fallout properties, (2) building protection principles, (3) details and planning suggestions, and (4) tabular data interpretation. A series of charts is…

Distribution, Characteristics, and Biotic Availability of Fallout, Operation Plumbbob

DTIC Science & Technology

1957-10-01

hours. Balloon mounted detonations produced fallout debris of higher water and acid solubility than did tower mounted detonations. The percentage of Sr89...of these radLoelements in fallout debris from balloon detonations than from tower detonations. The amounts of water- soluble Ba140 and Sr89, 90...99 5.3.1 Magnetic Properties ........................ 99 5.3.2 Solubility .............................. 100 5.3.2.1

Acidification of lakes in Canada by acid precipitation and the resulting effects on fishes

Treesearch

Richard J. Beamish

1976-01-01

There are several areas in Canada that could receive acidic fallout. Only in the area that produces Canada's largest single source of sulfur oxides has there been appreciable research. In the Sudbury region of Ontario, Canada, fallout of sulfur oxides has been shown to be responsible for damage to vegetation, lakes and fishes. The acidic fallout has been shown to...

Alpha-emitting nuclides in the marine environment

NASA Astrophysics Data System (ADS)

Pentreath, R. J.

1984-06-01

The occurrence of alpha-emitting nuclides and their daughter products in the marine environment continues to be a subject of study for many reasons. Those nuclides which occur naturally, in the uranium, thorium and actinium series, are of interest because of their value in determining the rates of geological and geochemical processes in the oceans. Studies of them address such problems as the determination of rates of transfer of particulate matter, deposition rates, bioturbation rates, and so on. Two of the natural alpha-series nuclides in which a different interest has been expressed are 210Po and 226Ra, because their concentrations in marine organisms are such that they contribute to a significant fraction of the background dose rates sustained both by the organisms themselves and by consumers of marine fish and shellfish. To this pool of naturally-occurring nuclides, human activities have added the transuranium nuclides, both from the atmospheric testing of nuclear devices and from the authorized discharges of radioactive wastes into coastal waters and the deep sea. Studies have therefore been made to understand the chemistry of these radionuclides in sea water, their association with sedimentary materials, and their accumulation by marine organisms, the last of these being of particular interest because the transuranics are essentially "novel" elements to the marine fauna and flora. The need to predict the long-term behaviour of these nuclides has, in turn, stimulated research on those naturally-occurring nuclides which may behave in a similar manner.

Tephra Fallout Hazard Assessment for VEI5 Plinian Eruption at Kuju Volcano, Japan, Using TEPHRA2

NASA Astrophysics Data System (ADS)

Tsuji, Tomohiro; Ikeda, Michiharu; Kishimoto, Hiroshi; Fujita, Koji; Nishizaka, Naoki; Onishi, Kozo

2017-06-01

Tephra fallout has a potential impact on engineered structures and systems at nuclear power plants. We provide the first report estimating potential accumulations of tephra fallout as big as VEI5 eruption from Kuju Volcano and calculated hazard curves at the Ikata Power Plant, using the TEPHRA2 computer program. We reconstructed the eruptive parameters of Kj-P1 tephra fallout deposit based on geological survey and literature review. A series of parameter studies were carried out to determine the best values of empirical parameters, such as diffusion coefficient and the fall time threshold. Based on such a reconstruction, we represent probabilistic analyses which assess the variation in meteorological condition, using wind profiles extracted from a 22 year long wind dataset. The obtained hazard curves and probability maps of tephra fallout associated to a Plinian eruption were used to discuss the exceeding probability at the site and the implications of such a severe eruption scenario.

Inventory simulation tools: Separating nuclide contributions to radiological quantities

NASA Astrophysics Data System (ADS)

Gilbert, Mark R.; Fleming, Michael; Sublet, Jean-Christophe

2017-09-01

The activation response of a material is a primary factor considered when evaluating its suitability for a nuclear application. Various radiological quantities, such as total (becquerel) activity, decay heat, and γ dose, can be readily predicted via inventory simulations, which numerically evolve in time the composition of a material under exposure to neutron irradiation. However, the resulting data sets can be very complex, often necessarily resulting in an over-simplification of the results - most commonly by just considering total response metrics. A number of different techniques for disseminating more completely the vast amount of data output from, in particular, the FISPACT-II inventory code system, including importance diagrams, nuclide maps, and primary knock-on atom (PKA) spectra, have been developed and used in scoping studies to produce database reports for the periodic table of elements. This paper introduces the latest addition to this arsenal - standardised and automated plotting of the time evolution in a radiological quantity for a given material separated by contributions from dominant radionuclides. Examples for relevant materials under predicted fusion reactor conditions, and for bench-marking studies against decay-heat measurements, demonstrate the usefulness and power of these radionuclide-separated activation plots. Note to the reader: the pdf file has been changed on September 22, 2017.

DELFIC: Department of Defense Fallout Prediction System. Volume I - Fundamentals

DTIC Science & Technology

1979-12-31

102 H2590D. DTIC•;. 17.) 1 i{1•ELECT ’ Prepared for " JAUG 2 ? 1980 Director DEFENSE NUCLEAR AGENCY B Wai’hington, D. C. 20305 808 1O8x Destroy this...2 1. INTRODUCTION AND OVERVIEW -- --- - -------------- - --- ---- 7 2. INITIALIZATION AND CLOUD RISE...61 6 1. INTRODUCTION AND OVERVIEW DELFIC (DEfense Land Fallout Interpretative Code) is intended for re- search in local nuclear fallout

Fallout Protection in School Construction. Proceedings, Association of School Business Officials of the United States and Canada (49th, Denver, Colorado, November 3-8, 1963).

ERIC Educational Resources Information Center

Roembke, James E.

Discussion of the effects of nuclear weapons and consequent radiation fallout precedes justification of the need for fallout shelters. Competition for the design of an elementary school with a population of 300-500 and an emergency population of 600-1000 is then described. Criteria and requirements are detailed. The winning entries illustrate…

New isotopic evidence of lead contamination in wheat grain from atmospheric fallout.

PubMed

Yang, Jun; Chen, Tongbin; Lei, Mei; Zhou, Xiaoyong; Huang, Qifei; Ma, Chuang; Gu, Runyao; Guo, Guanghui

2015-10-01

Crops could accumulate trace metals by soil-root transfer and foliar uptake from atmospheric fallout, and an accurate assessment of pollution sources is a prerequisite for preventing heavy metal pollution in agricultural products. In this study, we examined Pb isotope rates to trace the sources of Pb in wheat grain grown in suburbs. Results showed that, even in zones with scarcely any air pollution spots, atmospheric fallout was still a considerable source of Pb accumulation in wheat. The concentration of Pb in wheat grain has poor correlation with that in farm soil. The Pb concentration in wheat grains with dust in bran coat was significantly higher than that in wheat grains, which indicates that Pb may accumulate by foliar uptake. The Pb isotope rate has obvious differences between the soil and atmospheric fallout, and scatter ratio is significantly closer between the wheat grain and atmospheric fallout. Atmospheric fallout is a more significant source of Pb concentration in wheat grains than in soil. As far as we know, this is the first study on the main sources of lead in grain crop (wheat) samples with isotope. This study aims to improve our understanding of the translocation of foliar-absorbed metals to nonexposed parts of plants.

Fallout Deposition in the Marshall Islands from Bikini and Enewetak Nuclear Weapons Tests

PubMed Central

Beck, Harold L.; Bouville, André; Moroz, Brian E.; Simon, Steven L.

2009-01-01

Deposition densities (Bq m-2) of all important dose-contributing radionuclides occurring in nuclear weapons testing fallout from tests conducted at Bikini and Enewetak Atolls (1946-1958) have been estimated on a test-specific basis for all the 31 atolls and separate reef islands of the Marshall Islands. A complete review of various historical and contemporary data, as well as meteorological analysis, was used to make judgments regarding which tests deposited fallout in the Marshall Islands and to estimate fallout deposition density. Our analysis suggested that only 20 of the 66 nuclear tests conducted in or near the Marshall Islands resulted in substantial fallout deposition on any of the 25 inhabited atolls. This analysis was confirmed by the fact that the sum of our estimates of 137Cs deposition from these 20 tests at each atoll is in good agreement with the total 137Cs deposited as estimated from contemporary soil sample analyses. The monitoring data and meteorological analyses were used to quantitatively estimate the deposition density of 63 activation and fission products for each nuclear test, plus the cumulative deposition of 239+240Pu at each atoll. Estimates of the degree of fractionation of fallout from each test at each atoll, as well as of the fallout transit times from the test sites to the atolls were used in this analysis. The estimates of radionuclide deposition density, fractionation, and transit times reported here are the most complete available anywhere and are suitable for estimations of both external and internal dose to representative persons as described in companion papers. PMID:20622548

Fallout deposition in the Marshall Islands from Bikini and Enewetak nuclear weapons tests.

PubMed

Beck, Harold L; Bouville, André; Moroz, Brian E; Simon, Steven L

2010-08-01

Deposition densities (Bq m(-2)) of all important dose-contributing radionuclides occurring in nuclear weapons testing fallout from tests conducted at Bikini and Enewetak Atolls (1946-1958) have been estimated on a test-specific basis for 32 atolls and separate reef islands of the Marshall Islands. A complete review of various historical and contemporary data, as well as meteorological analysis, was used to make judgments regarding which tests deposited fallout in the Marshall Islands and to estimate fallout deposition density. Our analysis suggested that only 20 of the 66 nuclear tests conducted in or near the Marshall Islands resulted in substantial fallout deposition on any of the 23 inhabited atolls. This analysis was confirmed by the fact that the sum of our estimates of 137Cs deposition from these 20 tests at each atoll is in good agreement with the total 137Cs deposited as estimated from contemporary soil sample analyses. The monitoring data and meteorological analyses were used to quantitatively estimate the deposition density of 63 activation and fission products for each nuclear test, plus the cumulative deposition of 239+240Pu at each atoll. Estimates of the degree of fractionation of fallout from each test at each atoll, as well as of the fallout transit times from the test sites to the atolls were used in this analysis. The estimates of radionuclide deposition density, fractionation, and transit times reported here are the most complete available anywhere and are suitable for estimations of both external and internal dose to representative persons as described in companion papers.

The application of retrospective luminescence dosimetry in areas affected by fallout from the semipalatinsk nuclear test site: an evaluation of potential.

PubMed

Bailiff, I K; Stepanenko, V F; Göksu, H Y; Jungner, H; Balmukhanov, S B; Balmukhanov, T S; Khamidova, L G; Kisilev, V I; Kolyado, I B; Kolizshenkov, T V; Shoikhet, Y N; Tsyb, A F

2004-12-01

Luminescence retrospective dosimetry techniques have been applied with ceramic bricks to determine the cumulative external gamma dose due to fallout, primarily from the 1949 test, in populated regions lying NE of the Semipalatinsk Nuclear Test Site in Altai, Russia, and the Semipalatinsk region, Kazakhstan. As part of a pilot study, nine settlements were examined, three within the regions of highest predicted dose (Dolon in Kazakshstan; Laptev Log and Leshoz Topolinskiy in Russia) and the remainder of lower predicted dose (Akkol, Bolshaya Vladimrovka, Kanonerka, and Izvestka in Kazakshstan; Rubtsovsk and Kuria in Russia) within the lateral regions of the fallout trace due to the 1949 test. The settlement of Kainar, mainly affected by the 24 September 1951 nuclear test, was also examined. The bricks from this region were found to be generally suitable for use with the luminescence method. Estimates of cumulative absorbed dose in air due to fallout for Dolon and Kanonerka in Kazakshstan and Leshoz Topolinskiy were 475 +/- 110 mGy, 240 +/- 60 mGy, and 230 +/- 70 mGy, respectively. The result obtained in Dolon village is in agreement with published calculated estimates of dose normalized to Cs concentration in soil. At all the other locations (except Kainar) the experimental values of cumulative absorbed dose obtained indicated no significant dose due to fallout that could be detected within a margin of about 25 mGy. The results demonstrate the potential suitability of the luminescence method to map variations in cumulative dose within the relatively narrow corridor of fallout distribution from the 1949 test. Such work is needed to provide the basis for accurate dose reconstruction in settlements since the predominance of short-lived radionuclides in the fallout and a high degree of heterogeneity in the distribution of fallout are problematic for the application of conventional dosimetry techniques.

Computer program FPIP-REV calculates fission product inventory for U-235 fission

NASA Technical Reports Server (NTRS)

Brown, W. S.; Call, D. W.

1967-01-01

Computer program calculates fission product inventories and source strengths associated with the operation of U-235 fueled nuclear power reactor. It utilizes a fission-product nuclide library of 254 nuclides, and calculates the time dependent behavior of the fission product nuclides formed by fissioning of U-235.

A new nuclide transport model in soil in the GENII-LIN health physics code

NASA Astrophysics Data System (ADS)

Teodori, F.

2017-11-01

The nuclide soil transfer model, originally included in the GENII-LIN software system, was intended for residual contamination from long term activities and from waste form degradation. Short life nuclides were supposed absent or at equilibrium with long life parents. Here we present an enhanced soil transport model, where short life nuclide contributions are correctly accounted. This improvement extends the code capabilities to handle incidental release of contaminant to soil, by evaluating exposure since the very beginning of the contamination event, before the radioactive decay chain equilibrium is reached.

Civil Defense Home Shelters: a Viable Defense Strategy for the 1990s

DTIC Science & Technology

1990-09-01

NUDET, ground-transmitted shock often arrives first. The exact circumstances depend 16 upon a complex mixture of seismic velocities of the soil and...settle out. This late-arriving fallout represents a very minor hazard to human health, because the radiation dose rate from fallout decays quickly...Barrier Shielding and Geometry Shielding (5:49) 34 Home Fallout Shelters A shelter should provide a place of safety from natural or man-made hazards

Surficial Studies of Mars Using Cosmogenic Nuclides

NASA Technical Reports Server (NTRS)

Nishiizumi, K.

2001-01-01

Cosmogenic nuclides (CNs) are produced by cosmic-ray nuclear interactions with target nuclei in rocks, soils, ice, and the atmosphere. Cosmogenic nuclides have been widely used for investigation of solar system matter for several decades. Stable nuclides, such as He-3, Ne-21, and Ar-38, are built up over time as the surface is exposed to cosmic rays. The concentrations of cosmogenic radionuclides, such as Be-10, Al-26, and C-14 also build up with exposure time but reach saturation values after several half-lives. Especially since the development of accelerator mass spectrometry (AMS), CNs in terrestrial samples have been routinely used for geomorphic studies such as glaciation, surface erosion, and tectonics, and studies of atmospheric and ocean circulation. Cosmogenic nuclides on Mars will be able to answer questions of exposure ages, erosion rates, tectonic events, and deposition rates of sediments and/or volatiles. The concentrations of cosmogenic stable nuclides give the integrated exposure time of the rock/mineral, and the activities of radionuclides give recent records for times back as long as a few half-lives.

Reconstruction and analysis of cesium-137 fallout deposition patterns in the Marshall Islands

NASA Astrophysics Data System (ADS)

Whitcomb, Robert Cleckley, Jr.

Estimates of 137Cs deposition due to fallout originating from nuclear weapons testing in the Marshall Islands have been made for several locations in the Marshall Islands. These retrospective estimates were based primarily on historical exposure rate and gummed film measurements. The methods used to reconstruct these deposition estimates are specific for six of the Pacific tests. These methods are also similar to those used in the National Cancer Institute study for reconstructing 131I deposition from the Nevada Test Site. Reconstructed cumulative deposition estimates are validated against contemporary measurements of 137Cs concentration in soil. This validation work also includes an accounting for estimated global fallout contributions. These validations show that the overall geometric bias in predicted-to-observed (P/O) ratios is 1.0 (indicating excellent agreement). The 5th and 95th percentile range of this distribution is 0.35--2.95. The P/O ratios for estimates using historical gummed film measurements tend to slightly over-predict more than estimates using exposure rate measurements. The methods produce reasonable estimates of deposition confirming that radioactive fallout occurred at atolls further south of the four northern atolls recognized by the Department of Energy as being affected by fallout. The deposition estimate methods, supported by the very good agreement between estimates and measurements, suggest that these methods can be used for other weapons testing fallout radionuclides with confidence.

Medical examination of Rongelap people six months after exposure to fallout

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bond, V.P.; Conard, R.A.; Robertson, J.S.

1955-04-01

Follow-up medical examinations were made of the Marshallese inhabitants of Rongelap Atoll 6 months after they had been exposed to atomic bomb fallout radiation during the Operation CASTLE test series in March, 1954. During the early acute period following exposure, these people had shown systemic effects and marked hematological changes resulting from penetrating gamma radiation; extensive superficial skin lesions and epilation associated principally with beta and soft gamma radiation from fallout material deposited on uncovered skin areas; and minimal internal contamination with fission products, resulting principally from ingestion of fallout material. At the time of the 6-month resurvey the individuals,more » in general, appeared healthy and normally active, and no deaths had occurred in the interim period. Chest X-rays of all individuals revealed no abnormalities ascribable to the fallout radiation. Analysis of hematological data obtained failed to demonstrate a significant effect of measles on the peripheral blood count. Neutrophile, lymphocyte, and platelet counts were not significantly different from counts taken on the 74th post-exposure day, and none of these values had returned to control levels.« less

Preliminary evaluation of crisis-relocation fallout-shelter options. Volume 2. Detailed analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santini, D.J.; Clinch, J.M.; Davis, F.H.

1982-12-01

This report presents a preliminary, detailed evaluation of various shelter options for use if the President orders crisis relocation of the US urban population because of strong expectation of a nuclear war. The availability of livable shelter space at 40 ft/sup 2/ per person (congregate-care space) by state is evaluated. Options are evaluated for construction of fallout shelters allowing 10 ft/sup 2/ per person - such shelters are designed to provide 100% survival at projected levels of radioactive fallout. The FEMA concept of upgrading existing buildings to act as fallout shelters can, in principle, provide adequate shelter throughout most ofmore » the US. Exceptions are noted and remedies proposed. In terms of upgrading existing buildings to fallout shelter status, great benefits are possible by turning away from a standard national approach and adopting a more site-specific approach. Existing FEMA research provides a solid foundation for successful crisis relocation planning, but the program can be refined by making suitable modifications in its locational, engineering, and institutionally specific elements.« less

Tracing Fallout Radionuclide Behavior During Atmospheric Deposition and Pedogenesis

NASA Astrophysics Data System (ADS)

Landis, J. D.

2017-12-01

Short-lived fallout radionuclides 7Be (54 day half-life) and 210Pbexcess (22.3 year half-life) inform problems in geomorphology covering timespans of days to decades. Linking these radionuclides together is a powerful strategy, since the ratio 7Be:210Pb can control for changes in the activity of each, provided that the tracers have similar behavior through relevant chemical and physical processes such as interception, sorption, dilution, transport, etc. To investigate the extent to which 7Be and 210Pbxs share a common behavior, I measured these radionuclides in atmospheric deposition, vegetation, and stable soil, sediment and peat profiles. Bulk deposition of 7Be and 210Pb was measured in weekly intervals for 6 years of continuous record. Samples of red oak leaves (Quercus rubra) were collected regularly over 4 years at a site co-located with precipitation collection. Soil pits were sampled by high resolution methods at regional, undisturbed sites. In all samples 7Be, 210Pb, and other nuclides were measured by high-precision gamma spectrometry. Depositional fluxes of 7Be and 210Pb were highly correlated, with 7Be:210Pb converging to the long-term mean activity ratio of ca. 10.5 over intervals of 7 to 14 days. Red oak foliage accumulated 7Be and 210Pb at a linear rate during both growth and senescence, and appeared to maintain a dynamic equilibrium with atmospheric deposition. Canopies of both forest and grass intercepted on the order of 50% of deposition; the remainder reached underlying soil, where 7Be activity showed an exponential decline due to rapid hydrologic penetration of soil surface. Features of 210Pbxs soil profiles, including a subsurface maximum, reflect the same penetration pattern integrated over decades of deposition. Application of the Linked Radionuclide aCcumulation (LRC) model demonstrated that 210Pb moves through soil, peat and fluvial sediment profiles at rates on the order of 1 mm per year, similar to other atmospherically-derived metals including Hg and 241Am. These observations suggest that the fates of 7Be, 210Pb and other atmospherically-derived metals are strongly linked by shared physical processes. An understanding of 7Be and 210Pb during deposition and pedogenesis can provide insights into the use of these and other tracers (e.g., 10Be) in studies of exposure age and erosion.

Operation REDWING. Project 2.64. Fallout Location and Delineation by Aerial Surveys.

DTIC Science & Technology

Fallout, *Gamma rays, *Radioactive contamination, Ocean environments, Nuclear explosion testing, Surveys, Sampling, Airborne, Surface burst, Sea water, Dose rate, Ocean surface, Coral reefs, Marshall Islands

Haz-Map Glossary

MedlinePlus

... lung. Radiation Accident Large-scale accidents from atomic bomb testing fallout released iodine-131 and strontium-90. ... lung. Radiation Accident Large-scale accidents from atomic bomb testing fallout released iodine-131 and strontium-90. ...

Strontium-90 deposition in New York City.

PubMed

Volchok, H L

1967-06-16

Measurements of strontium-90 deposited in New York City over the past 12 years make for broader understanding of the fallout phenomenon. The data indicate a stratospheric half-residence time of 8 to 10 months. The seasonal oscillation of strontium-90 fallout is very symmetrical and consistent from year to year and completely independent of the timing and magnitude of nuclear tests. The predicted fallout of strontium-90 in 1970 is less than 1 percent of that during the peak year 1963.

ANTS (FORMICA RUFA) AS POSSIBLE INDICATORS FOR RADIOACTIVE FALLOUT (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chauvin, R.; Courtois, G.; Anguenot, F.

1963-01-01

A measurement of the radioactivity of anthills was made, and the results lead to the conclusion that the radioactivity is found in the ants and not in the anthills themselves. An examination of the gamma spectrum shows an apparent period of 38 days. It is suggested that the ants fix the fallout by a mechanism in direct connection with their habit of sampling the sugar excretion of tree aphis. The impontance of ants as fallout detectors cannot be evaluated as yet. (J.S.R.)

Nuclear Data Sheets for A=159

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reich C. W.; Reich,C.W.

2012-01-01

The experimental results from the various reaction and radioactive decay studies leading to nuclides in the A = 159 mass chain have been reviewed. Nuclides ranging from Pm (Z = 61) through Os (Z = 74) are included. These data are summarized and presented, together with adopted level schemes and properties. This work supersedes the previous evaluation of the data on these nuclides (2003He11).

State of volcanic ash dispersion prediction

NASA Astrophysics Data System (ADS)

Eliasson, Jonas; Palsson, Thorgeir; Weber, Konradin

2017-04-01

The Eyjafjallajokull 2010 and Grimsvotn 2011 eruptions created great problems for commercial aviation in Western Europe and in the North Atlantic region. Comparison of satellite images of the visible and predicted ash clouds showed the VAAC prediction to be much larger than the actual ash clouds. No official explanation of this discrepancy exists apart from the definition of the ash cloud boundary. Papers on simulation of the Eyjafjallajökull ash cloud in peer reviewed journals, typically attempted to simulate the VAAC predictions rather than focusing on the satellite pictures. Sporadic measurements made in-situ showed much lower ash concentrations over Europe than the predicted values. Two of the weak points in ash cloud prediction have been studied in airborne measurements of volcanic ash by the Universities in Kyoto Japan, Iceland and Düsseldorf Germany of eruptions in Sakurajima, Japan. It turns out that gravitational deformation of the plume and a streak fallout process make estimated ash content of clouds larger than the actual, both features are not included in the simulation model. Tropospheric plumes tend to ride in stable inversions this causes gravitational flattening (pancaking) of the volcanic plume, while diffusion in the mixing layer is insignificant. New rules from ICAO, effective from November 2014, reiterate that jetliners should avoid visible ash, this makes information on visible ash important. A procedure developed by JMÁs Tokyo VAAC uses satellite images of visible ash to correct the prediction. This and the fact that meteorological data necessary to model gravitational dispersion and streak fallout do not exist in the international database available to the VAAĆs. This shows that close monitoring by airborne measurements and satellite and other photographic surveillance is necessary.

7 CFR 760.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Control Act (15 U.S.C. 2602). (h) Nuclear Radiation or Fallout means contamination from nuclear radiation... nuclear radiation or fallout in such whole milk by tests made by a public agency or under a testing...

7 CFR 760.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Control Act (15 U.S.C. 2602). (h) Nuclear Radiation or Fallout means contamination from nuclear radiation... nuclear radiation or fallout in such whole milk by tests made by a public agency or under a testing...

7 CFR 760.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Control Act (15 U.S.C. 2602). (h) Nuclear Radiation or Fallout means contamination from nuclear radiation... nuclear radiation or fallout in such whole milk by tests made by a public agency or under a testing...

7 CFR 760.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Control Act (15 U.S.C. 2602). (h) Nuclear Radiation or Fallout means contamination from nuclear radiation... nuclear radiation or fallout in such whole milk by tests made by a public agency or under a testing...

137Cs in soil and fallout around Zagreb (Croatia) at the time of the Fukushima accident.

PubMed

Šoštarić, Marko; Petrinec, Branko; Babić, Dinko

2013-12-01

This paper addresses the noticeable increase of 137Cs activity concentrations in soil and fallout in the area surrounding Zagreb (Croatia) that occurred at the time of the 2011 Fukushima accident. This topic is important for public health as 137Cs is highly toxic due to its long half-life of radioactive decay and chemical similarity to potassium. 137Cs concentrations in fallout were much greater than in soil, but remained present longer in the latter. While being detectable in our measurements, 137Cs did not spread through the food chain in amounts exceeding the maximum allowed level of radioactive food contamination. However, more thorough and consistent measurements need to be done in order to establish the precise activity trends of 137Cs in Zagreb soil and fallout.

Attraction of Hawaiian seabirds to lights: conservation efforts and effects of moon phase

USGS Publications Warehouse

Telfer, T.C.; Sincock, J.L.; Byrd, G.V.; Reed, J.R.

1987-01-01

Increased urban lighting on Kauai Island, Hawaii, has resulted in new problems for threatened and endangered procellariiform birds. Between 1978 and 1985,11,767 Kewell's shearwaters, 38 dark-rumped petrels, and 8 band-rumped storm petrels were attracted to bright urban lights, struck unseen objects, and fell to the ground. A salvage effort involving public cooperation and government-run 'aid stations' has returned 90% of these birds to the wild. Nightly fallout of seabirds was significantly reduced during the full moon, but fallout increased as the new moon approached. The heaviest fallout occurred in urban coastal areas, particularly at river mouths. More than 97% of the fallout involved fledgling birds apparently leaving their mountain nesting grounds for the first time. Less than 1%of these birds were recovered again on subsequent nights.

Spatial and temporal distribution of Pu in the Northwest Pacific Ocean using modern coral archives.

PubMed

Lindahl, Patric; Andersen, Morten B; Keith-Roach, Miranda; Worsfold, Paul; Hyeong, Kiseong; Choi, Min-Seok; Lee, Sang-Hoon

2012-04-01

Historical (239)Pu activity concentrations and (240)Pu/(239)Pu atom ratios were determined in skeletons of dated modern corals collected from three locations (Chuuk Lagoon, Ishigaki Island and Iki Island) to identify spatial and temporal variations in Pu inputs to the Northwest Pacific Ocean. The main Pu source in the Northwest Pacific is fallout from atmospheric nuclear weapons testing which consists of global fallout and close-in fallout from the former US Pacific Proving Grounds (PPG) in the Marshall Islands. PPG close-in fallout dominated the Pu input in the 1950s, as was observed with higher (240)Pu/(239)Pu atom ratios (>0.30) at the Ishigaki site. Specific fallout Pu contamination from the Nagasaki atomic bomb and the Ivy Mike thermonuclear detonation at the PPG were identified at Ishigaki Island from the (240)Pu/(239)Pu atom ratios of 0.07 and 0.46, respectively. During the 1960s and 1970s, global fallout was the major Pu source to the Northwest Pacific with over 60% contribution to the total Pu. After the cessation of the atmospheric nuclear tests, the PPG again dominated the Pu input due to the continuous transport of remobilised Pu from the Marshall Islands along the North Equatorial Current and the subsequent Kuroshio Current. The Pu contributions from the PPG in recent coral bands (1984 onwards) varied over time with average estimated PPG contributions between 54% and 72% depending on location. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cosmogenic nuclide budgeting of floodplain sediment transfer

NASA Astrophysics Data System (ADS)

Wittmann, H.; von Blanckenburg, F.

2009-08-01

Cosmogenic nuclides produced in quartz may either decay or accumulate while sediment is moved through a river basin. A change in nuclide concentration resulting from storage in a floodplain is potentially important in large drainage basins in which sediment is prone to repeated burial and remobilization as a river migrates through its floodplain. We have modeled depth- and time-dependent cosmogenic nuclide concentration changes for 10Be, 26Al, and 14C during sediment storage and mixing in various active floodplain settings ranging from confined, shallow rivers with small floodplains to foreland-basin scale floodplains traversed by deep rivers. Floodplain storage time, estimated from channel migration rates, ranges from 0.4 kyr for the Beni River basin (Bolivia) to 7 kyr for the Amazon River basin, while floodplain storage depth, estimated from channel depth, ranges from 1 to 25 m. For all modeled active floodplain settings, the long-lived nuclides 10Be and 26Al show neither significant increase in nuclide concentration from irradiation nor decrease from decay. We predict a hypothetical response time after which changes in 10Be or 26Al concentrations become analytically resolvable. This interval ranges from 0.07 to 2 Myr and exceeds in all cases the typical residence time of sediment in a floodplain. Due to the much shorter half life of 14C, nuclide concentrations modeled for the in situ-produced variety of this nuclide are, however, sensitive to floodplain storage on residence times of < 20 kyr. The cosmogenic nuclide composition of old deposits in currently inactive floodplains that have been isolated for periods of millions of years from the river that once deposited them is predicted to either increase or decrease in 10Be and 26Al concentration, depending on the depositional depth. These conditions can be evaluated using the 26Al/ 10Be ratio that readily discloses the depth and duration of storage. We illustrate these models with examples from the Amazon basin. As predicted, modern bedload collected from an Amazon tributary, the Bolivian Beni River, shows no systematic change in nuclide concentration as sediment is moved through 500 km of floodplain by river meandering. In contrast, in the central Amazon floodplain currently untouched by the modern river system, low 26Al/ 10Be ratios account for minimum burial depths of 5 to 10 m for a duration of > 5 Myr. The important result of this analysis is that in all likely cases of active floodplains, cosmogenic 10Be and 26Al concentrations remain virtually unchanged over the interval sediment usually spends in the basin. Thus, spatially-averaged denudation rates of the sediment-producing area can be inferred throughout the entire basin, provided that nuclide production rates are scaled for the altitudes of the sediment-producing area only, because floodplain storage does not modify nuclide concentrations introduced from the sediment source area.

A multi-layered active target for the study of neutron-unbound nuclides at NSCL

NASA Astrophysics Data System (ADS)

Freeman, Jessica; Gueye, Paul; Redpath, Thomas; MoNA Collaboration

2017-01-01

The characteristics of neutron-unbound nuclides were investigated using a multi-layered Si/Be active target designed for use with the MoNA/LISA setup at the National Superconducting Cyclotron (NSCL). The setup consists of the MoNA/LISA arrays (for neutron detection) and a superconducting sweeper magnet (for charged separation) to identify products following the decay of neutron unbound states. The segmented target consisted of three 700 mg/cm2 beryllium targets and four 0.14 mm thick 62x62 mm2 silicon detectors. As a commissioning experiment for the target the decay of two-neutron unbound 26O populated in a one-proton removal reaction from a radioactive 27F beam was performed. The 27F secondary radioactive beam from the NSCL's Coupled Cyclotron Facility was produced from the fragmentation of a 140 MeV/u 48Ca beam incident on a thick beryllium target and then cleanly selected by the A1900 fragment separator. The energy loss and position spectra of the incoming beam and reaction products were used to calibrate the Silicon detectors to within 1.5% in both energy and position. A dedicated Geant4 model of the target was developed to simulate the energy loss within the target. A description of the experimental setup, simulation work, and energy and position calibration will be presented. DoE/NNSA - DE-NA0000979.

Update and evaluation of decay data for spent nuclear fuel analyses

NASA Astrophysics Data System (ADS)

Simeonov, Teodosi; Wemple, Charles

2017-09-01

Studsvik's approach to spent nuclear fuel analyses combines isotopic concentrations and multi-group cross-sections, calculated by the CASMO5 or HELIOS2 lattice transport codes, with core irradiation history data from the SIMULATE5 reactor core simulator and tabulated isotopic decay data. These data sources are used and processed by the code SNF to predict spent nuclear fuel characteristics. Recent advances in the generation procedure for the SNF decay data are presented. The SNF decay data includes basic data, such as decay constants, atomic masses and nuclide transmutation chains; radiation emission spectra for photons from radioactive decay, alpha-n reactions, bremsstrahlung, and spontaneous fission, electrons and alpha particles from radioactive decay, and neutrons from radioactive decay, spontaneous fission, and alpha-n reactions; decay heat production; and electro-atomic interaction data for bremsstrahlung production. These data are compiled from fundamental (ENDF, ENSDF, TENDL) and processed (ESTAR) sources for nearly 3700 nuclides. A rigorous evaluation procedure of internal consistency checks and comparisons to measurements and benchmarks, and code-to-code verifications is performed at the individual isotope level and using integral characteristics on a fuel assembly level (e.g., decay heat, radioactivity, neutron and gamma sources). Significant challenges are presented by the scope and complexity of the data processing, a dearth of relevant detailed measurements, and reliance on theoretical models for some data.

Nuclear Data Sheets for A = 68

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCutchan, E. A.

2012-07-01

The experimental results from the various reaction and radioactive decay studies leading to nuclides in the A = 68 mass chain have been reviewed. Nuclides ranging from Cr (Z = 24) to Br (Z = 35) are included. For these nuclei, level and decay schemes, as well as tables of nuclear properties, are given. This work supersedes the previous evaluation of the data on these nuclides (2002Bu29).

Plutonium Isotopes in the Terrestrial Environment at the Savannah River Site, USA. A Long-Term Study

DOE PAGES

Armstrong, Christopher R.; Nuessle, Patterson R.; Brant, Heather A.; ...

2015-01-16

This work presents the findings of a long term plutonium study at Savannah River Site (SRS) conducted between 2003 and 2013. Terrestrial environmental samples were obtained at Savannah River National Laboratory (SRNL) in A-area. Plutonium content and isotopic abundances were measured over this time period by alpha spectrometry and three stage thermal ionization mass spectrometry (3STIMS). Here we detail the complete sample collection, radiochemical separation, and measurement procedure specifically targeted to trace plutonium in bulk environmental samples. Total plutonium activities were determined to be not significantly above atmospheric global fallout. However, the 238Pu/ 239+240Pu activity ratios attributed to SRS aremore » above atmospheric global fallout ranges. The 240Pu/ 239Pu atom ratios are reasonably consistent from year to year and are lower than fallout, while the 242Pu/ 239Pu atom ratios are higher than fallout values. Overall, the plutonium signatures obtained in this study reflect a mixture of weapons-grade, higher burn-up, and fallout material. This study provides a blue print for long term low level monitoring of plutonium in the environment.« less

Extension of 239+240Pu sediment geochronology to coarse-grained marine sediments

USGS Publications Warehouse

Kuehl, Steven A.; Ketterer, Michael E.; Miselis, Jennifer L.

2012-01-01

Sediment geochronology of coastal sedimentary environments dominated by sand has been extremely limited because concentrations of natural and bomb-fallout radionuclides are often below the limit of measurement using standard techniques. ICP-MS analyses of 239+240Pu from two sites representative of traditionally challenging (i.e., low concentration) environments provide a "proof of concept" and demonstrate a new application for bomb-fallout radiotracers in the study of sandy shelf-seabed dynamics. A kasten core from the New Zealand shelf in the Southern Hemisphere (low fallout), and a vibracore from the sandy nearshore of North Carolina (low particle surface area) both reveal measurable 239+240Pu activities at depth. In the case of the New Zealand site, independently verified steady-state sedimentation results in a 239+240Pu profile that mimics the expected atmospheric fallout. The depth profile of 239+240Pu in the North Carolina core is more uniform, indicating significant sediment resuspension, which would be expected in this energetic nearshore environment. This study, for the first time, demonstrates the utility of 239+240Pu in the study of sandy environments, significantly extending the application of bomb-fallout isotopes to coarse-grained sediments, which compose the majority of nearshore regions.

Probabilistic tephra hazard maps for the Neapolitan area: Quantitative volcanological study of Campi Flegrei eruptions

NASA Astrophysics Data System (ADS)

Mastrolorenzo, G.; Pappalardo, L.; Troise, C.; Panizza, A.; de Natale, G.

2008-07-01

Tephra fall is a relevant hazard of Campi Flegrei caldera (Southern Italy), due to the high vulnerability of Naples metropolitan area to such an event. Here, tephra derive from magmatic as well as phreatomagmatic activity. On the basis of both new and literature data on known, past eruptions (Volcanic Explosivity Index (VEI), grain size parameters, velocity at the vent, column heights and erupted mass), and factors controlling tephra dispersion (wind velocity and direction), 2D numerical simulations of fallout dispersion and deposition have been performed for a large number of case events. A bayesian inversion has been applied to retrieve the best values of critical parameters (e.g., vertical mass distribution, diffusion coefficients, velocity at the vent), not directly inferable by volcanological study. Simulations are run in parallel on multiple processors to allow a fully probabilistic analysis, on a very large catalogue preserving the statistical proprieties of past eruptive history. Using simulation results, hazard maps have been computed for different scenarios: upper limit scenario (worst-expected scenario), eruption-range scenario, and whole-eruption scenario. Results indicate that although high hazard characterizes the Campi Flegrei caldera, the territory to the east of the caldera center, including the whole district of Naples, is exposed to high hazard values due to the dominant westerly winds. Consistently with the stratigraphic evidence of nature of past eruptions, our numerical simulations reveal that even in the case of a subplinian eruption (VEI = 3), Naples is exposed to tephra fall thicknesses of some decimeters, thereby exceeding the critical limit for roof collapse. Because of the total number of people living in Campi Flegrei and the city of Naples (ca. two million of inhabitants), the tephra fallout risk related to a plinian eruption of Campi Flegrei largely matches or exceeds the risk related to a similar eruption at Vesuvius.

Evaluation of the radioactive contamination in fungi genus Boletus in the region of Europe and Yunnan Province in China.

PubMed

Falandysz, Jerzy; Zalewska, Tamara; Krasińska, Grażyna; Apanel, Anna; Wang, Yuanzhong; Pankavec, Sviatlana

2015-10-01

Numerous species of wild-grown mushrooms are among the most vulnerable organisms for contamination with radiocesium released from a radioactive fallout. A comparison was made on radiocesium as well as the natural gamma ray-emitting radionuclide ((40)K) activity concentrations in the fruiting bodies of several valued edible Boletus mushrooms collected from the region of Europe and Yunnan Province in China. Data available for the first time for Boletus edulis collected in Yunnan, China, showed a very weak contamination with (137)Cs. Radiocesium concentration activity of B. edulis samples that were collected between 2011 and 2014 in Yunnan ranged from 5.2 ± 1.7 to 10 ± 1 Bq kg(-1) dry matter for caps and from 4.7 ± 1.3 to 5.5 ± 1.0 Bq kg(-1) dry matter for stipes. The mushrooms Boletus badius, B. edulis, Boletus impolitus, Boletus luridus, Boletus pinophilus, and Boletus reticulatus collected from the European locations between 1995 and 2010 showed two to four orders of magnitude greater radioactivity from (137)Cs compared to B. edulis from Yunnan. The nuclide (40)K in B. badius was equally distributed between the caps and stipes, while for B. edulis, B. impolitus, B. luridus, B. pinophilus, and B. reticulatus, the caps were richer, and for each mushroom, activity concentration seemed to be more or less species-specific.

Chlorine-36 in Water, Snow, and Mid-Latitude Glacial Ice of North America: Meteoric and Weapons-Tests Production in the Vicinity of the Idaho National Engineering and Environmental Laboratory, Idaho

DOE Office of Scientific and Technical Information (OSTI.GOV)

L. DeWayne; J. R. Green; S. Vogt, P. Sharma

1999-01-01

Measurements of chlorine-36 (36Cl) were made for 64 water, snow, and glacial-ice and -runoff samples to determine the meteoric and weapons-tests-produced concentrations and fluxes of this radionuclide at mid-latitudes in North America. The results will facilitate the use of 36Cl as a hydrogeologic tracer at the Idaho National Engineering and Environmental Laboratory (INEEL). This information was used to estimate meteoric and weapons-tests contributions of this nuclide to environmental inventories at and near the INEEL. The data presented in this report suggest a meteoric source 36Cl for environmental samples collected in southeastern Idaho and western Wyoming if the concentration is lessmore » than 1 x 10 7 atoms/L. Additionally, concentrations in water, snow, or glacial ice between 1 x 10 7 and 1 x 10 8 atoms/L may be indicative of a weapons-tests component from peak 36Cl production in the late 1950s. Chlorine-36 concentrations between 1 x 10 8 and 1 x 10 9 atoms/L may be representative of re-suspension of weapons-tests fallout airborne disposal of 36Cl from the INTEC, or evapotranspiration. It was concluded from the water, snow, and glacial data presented here that concentrations of 36Cl measured in environmental samples at the INEEL larger than 1 x 10 9 atoms/L can be attributed to waste-disposal practices.« less

Radioecologycal study of {sup 239/240}Pu in Bangka Island and Muria Peninsula: Determination of {sup 239/240}Pu in marine sediment and seawater as part of baseline data collecting for sitting of candidates of first Indonesia NPP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suseno, Heny, E-mail: henis@batan.go.id; Wisnubroto, Djarot S.

Radioisotope Pu-239/240 are alpha emitting nuclides important indicators of radioactive contamination of the marine environment. Global fallout is the main source of plutonium in the marine environment. There are very limited study on {sup 239/240}Pu in Indonesia coastal environments. The data of this radioisotopes is needed for baseline data of nuclear power plant (NPP) site candidates both in Bangka Island and Muria Peninsula. Bottom sediments play an important role in radioecological studies of the marine environment because a large proportion of radioactive substances entering the sea is adsorbed over time onto suspended particulate matter and deposited in sediments. Plutonium ismore » particle reactive and deposited in marine sediment. Radioisotope {sup 239/240}Pu was determinated by alpha spectrometry after radiochemical procedure that was performed in both water and marine sediment from Bangka Island and Muria Peninsula. The sediment baseline of concentration {sup 239/240}Pu in Bangka Island and Muria Peninsula were range from 0.013 to 0.021 Bq.kg{sup −1} and 0.018 to 0.024 Bq.kg{sup −1} respectively. The water baseline concentration this isotope were range from 2.73 to 4.05 mBq.m{sup −3} and 2.98 to 4.50 mBq.m{sup −3}.« less

Radiochemical techniques for determining some naturally occurring radionuclides in marine environmental materials

NASA Astrophysics Data System (ADS)

Baker, C. W.

1984-06-01

The determination of some of the naturally-occurring, alpha-emitting radionuclides in marine environmental materials, is of interest for several reasons. Radium and radon nuclides are potentially useful as oceanographic tracers. Lead and thorium nuclides may be used to study sedimentation rates, mixing processes and bioturbation in sediments. Radium and polonium nuclides are incorporated into food chains and the data may provide a perspective against which to assess the significance, for marine organisms, of exposure to radiation in a marine radioactive waste disposal situation. This paper discusses the manner in which samples are taken, and the radiochemical methods which have been employed to measure the nuclides, together with some data produced.

Development of Advanced Nuclide Separation and Recovery Methods using Ion-Exchanhge Techniques in Nuclear Backend

NASA Astrophysics Data System (ADS)

Miura, Hitoshi

The development of compact separation and recovery methods using selective ion-exchange techniques is very important for the reprocessing and high-level liquid wastes (HLLWs) treatment in the nuclear backend field. The selective nuclide separation techniques are effective for the volume reduction of wastes and the utilization of valuable nuclides, and expected for the construction of advanced nuclear fuel cycle system and the rationalization of waste treatment. In order to accomplish the selective nuclide separation, the design and synthesis of novel adsorbents are essential for the development of compact and precise separation processes. The present paper deals with the preparation of highly functional and selective hybrid microcapsules enclosing nano-adsorbents in the alginate gel polymer matrices by sol-gel methods, their characterization and the clarification of selective adsorption properties by batch and column methods. The selective separation of Cs, Pd and Re in real HLLW was further accomplished by using novel microcapsules, and an advanced nuclide separation system was proposed by the combination of selective processes using microcapsules.

Deposition of atmospheric heavy metals to the Greenland ice sheet from the 1783-1784 volcanic eruption of Laki, Iceland

NASA Astrophysics Data System (ADS)

Hong, Sungmin; Candelone, Jean-Pierre; Boutron, Claude F.

1996-11-01

In order to assess better the influence of major volcanic events on the large scale atmospheric cycles of heavy metals, Greenland ice dated from the time of the fallouts from the great 1783-1784 eruption of Laki volcano in Iceland has been analysed for Pb, Cd, Cu, Zn and sulphate. The concentrations of the four heavy metals investigated are found to be greatly enhanced in the ice layers which correspond to the fallouts from the eruption, confirming that such events do modify the atmospheric cycles of heavy metals. Cumulative fallout of heavy metals to the whole Greenland ice cap from the 1783-1784 Laki eruption ranges from 1 t for Pb and Cd to 40 t for Zn. For Cd, Cu and Zn, it represents a few percent of the cumulative anthropogenic fallout to the ice cap from the Industrial Revolution to the present.

Nuclear Data Sheets for A = 34

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nica N.; Nica,N.; Singh,B.

2012-07-01

Nuclear spectroscopic information for experimentally investigated nuclides of mass 34 (Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K, Ca) has been evaluated. The principal sources of the Adopted Levels presented for nuclides close to the stability line are Endt's evaluations (1990En08, 1978En02). The data sets for reactions and decays, including all available gamma-ray data, are based mostly on the original literature. There are no data available for the excited states in {sup 34}Ne and {sup 34}Na. The existence of the {sup 34}K and {sup 34}Ca nuclides has been searched and reported in a secondary publication but no evidencemore » was found for their detection. Both nuclides are possible candidates for one or two-proton emission. Only upper limits of half-lives have been proposed based on expected cross sections. Decay schemes for the {beta} decays of {sup 34}Ne, {sup 34}Na, {sup 34}Mg, and {sup 34}Si are not known. Very little information is available for {beta}-delayed neutron decays of {sup 35}Na, {sup 35}Mg and {sup 35}Si which lead to population of levels in A = 34 nuclides. Neutron-rich nuclides in this mass region are relevant to 'island of inversion'.« less

Development of observed precipitation and meteorological database to understand the wet deposition and dispersion processes in March 2011

NASA Astrophysics Data System (ADS)

Yatagai, Akiyo; Watanabe, Akira; Ishihara, Masahito; Ishihara, Hirohiko; Takara, Kaoru

2014-05-01

The transport and diffusion of the radioactive pollutants from the Fukushima-Daiichi NPP inthe atmosphere caused a disaster for residents in and around Fukushima. Studies have sought to understand the transport, diffusion, and deposition process, and to understand the movement of radioactive pollutants through the soil, vegetation, rivers, and groundwater. However, a detailed simulation and understanding of the distribution of radioactive compounds depend on a simulation of precipitation and on the information on the timing of the emission of these radioactive pollutants from the NPP. Further, precipitation type and its amount affect the various transport process of the radioactive nuclides. Hence, this study first examine the qualitative precipitation pattern and timing in March 2011 using X-band radar data from Fukushima University and three dimensional C-band radar data network of Japan Meteorological Agency. Second, by collecting rain-gauge network and other surface meteorological data, we estimate quantitative precipitation and its type (rain/snow) according to the same method used to create APHRODITE daily grid precipitation (Yatagai et al., 2012) and judge of rain/snow (Yasutomi et al., 2011). For example, the data clarified that snowfall was observed on the night of Mar 15 into the morning of Mar 16 throughout Fukushima prefecture. This had an important effect on the radioactive contamination pattern in Fukushima prefecture. The precipitation pattern itself does not show one-on-one correspondence with the contamination pattern. While the pollutants transported northeast of the NPP and through north Kanto (about 200 km southwest of Fukushima and, 100 km north of Tokyo) went to the northeast, the timing of the precipitation causing the fallout, i.e., wet-deposition, is important. Although the hourly Radar-AMeDAS 1-km-mesh precipitation data of JMA are available publically, it does not represent the precipitation pattern in Nakadori, in central Fukushima prefecture. Hence, we used 10-minute interval X-band radar, located in north Nakadori to determine the start and detailed horizontal pattern (120-m mesh) of the precipitation. The developed precipitation and other meteorological dataset will be released to the project Fukushima-IRIS site (http://firis.dpri.kyoto-u.ac.jp, or linked from http://center.stelab.nagoya-u.ac.jp/member/akiyoyatagai/). The project aims to make a database to understand the initial meteorological condition. Various useful sites with meteorological data and other physical information on March 2011 have already linked at the site. This project is being supported by the Disaster Prevention Research Institute, Kyoto University.

Neogene basin infilling from cosmogenic nuclides (10Be and 21Ne) in Atacama, Chile

NASA Astrophysics Data System (ADS)

Sanchez, Caroline; Regard, Vincent; Carretier, Sébastien; Riquelme, Rodrigo; Blard, Pierre-Henri; Campos, Eduardo; Brichau, Stéphanie; Lupker, Marteen; Hérail, Gérard

2017-04-01

In the hyperarid Atacama Desert, northern Chile, Neogene sediments host copper rich layers (exotic supergene mineralization). Current mines are excavated into relatively thin (<200-300 m) Neogene basins whose infilling chronology is poorly constrained. We took advantage of one of these mining pits, and sampled for 10Be and 21Ne cosmogenic nuclide dosing. These cosmogenic nuclides help constraining the infilling chronology. Indeed, basin sediments were deposited with a cosmogenic nuclide content acquired on hillslopes. Then within the basin, cosmogenic nuclide concentrations evolved through the competing production (quickly decreasing with depth) and disintegration (not for 21Ne). Sampling depths are at ˜100 m and at ˜50 m below the desert surface. First, 21Ne gives lower boundaries for upstream erosion rates or local sedimentation rate. These bounds are between 2 and 10 m/Ma, which is quite important for the area. The ratio between the two cosmogenic nuclides indicate a maximum burial age of 12 Ma (minimal erosion rate of 15 m/Ma) and is surprisingly similar from bottom to top, indicating a probable rapid infilling. We finally processed a Monte-Carlo inversion. This inversion helps taking into account the post-deposition muonic production of cosmogenic nuclides. Inversion results is dependent on the muonic production scheme. Interestingly, the similarity in concentrations from bottom to top pleads for quite low production at depth. Our data finally indicates a quick infilling between 12.5 and 10 Ma BP accounting for ˜100 m of deposition (minimum sedimentation rate of 40 m/Ma).

Dynamic Monitoring of Cleanroom Fallout Using an Air Particle Counter

NASA Technical Reports Server (NTRS)

Perry, Radford

2011-01-01

The particle fallout limitations and periodic allocations for the James Webb Space Telescope are very stringent. Standard prediction methods are complicated by non-linearity and monitoring methods that are insufficiently responsive. A method for dynamically predicting the particle fallout in a cleanroom using air particle counter data was determined by numerical correlation. This method provides a simple linear correlation to both time and air quality, which can be monitored in real time. The summation of effects provides the program better understanding of the cleanliness and assists in the planning of future activities. Definition of fallout rates within a cleanroom during assembly and integration of contamination-sensitive hardware, such as the James Webb Space Telescope, is essential for budgeting purposes. Balancing the activity levels for assembly and test with the particle accumulation rate is paramount. The current approach to predicting particle fallout in a cleanroom assumes a constant air quality based on the rated class of a cleanroom, with adjustments for projected work or exposure times. Actual cleanroom class can also depend on the number of personnel present and the type of activities. A linear correlation of air quality and normalized particle fallout was determined numerically. An air particle counter (standard cleanroom equipment) can be used to monitor the air quality on a real-time basis and determine the "class" of the cleanroom (per FED-STD-209 or ISO-14644). The correlation function provides an area coverage coefficient per class-hour of exposure. The prediction of particle accumulations provides scheduling inputs for activity levels and cleanroom class requirements.

A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

DOE PAGES

Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.; ...

2016-12-15

Reprocessed earth material is a glassy nuclear fallout debris from near-surface nuclear tests. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. Our study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclearmore » test (“trinitite”) and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. Furthermore, the volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.« less

Fukushima-derived radiocesium fallout in Hawaiian soils.

PubMed

McKenzie, Trista; Dulai, Henrietta

2017-12-01

Several reactors at the Fukushima Dai-ichi Nuclear Power Plant suffered damage on March 11, 2011, resulting in the release of radiocesium ( 134 Cs and 137 Cs), as well as other radionuclides, into the atmosphere. A week later, these isotopes were detected in aerosols over the state of Hawai'i and in milk samples analyzed on the island of Hawai'i. This study estimated the magnitude of cesium deposition in soil, collected in 2015-2016, resulting from atmospheric fallout. It also examined the patterns of cesium wet deposition with precipitation observed on O'ahu and the island of Hawai'i following the disaster. Fukushima-derived fallout was differentiated from historic nuclear weapons testing fallout by the presence of 134 Cs and the assumption that the 134 Cs to 137 Cs ratio was 1:1. Detectable, Fukushima-derived 134 Cs inventories ranged from 30 to 630 Bq m -2 and 137 Cs inventories ranged from 20 to 2200 Bq m -2 . Fukushima-derived cesium inventories in soils were related to precipitation gradients, particularly in areas where rainfall exceeded 200 mm between March 19 and April 4, 2011. This research confirmed and quantified the presence of Fukushima-derived fallout in the state of Hawai'i in amounts higher than predicted by models and observed in the United States mainland, however the activities detected were an order of magnitude lower than fallout associated with historic sources such as the nuclear weapons testing in the Pacific. In addition, this study showed that areas of highest cesium deposition do not overlap with densely populated or agriculturally used areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

NASA Astrophysics Data System (ADS)

Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.; Zimmer, Mindy M.; Pollington, Anthony D.; Rector, Kirk D.

2017-01-01

Glassy nuclear fallout debris from near-surface nuclear tests is fundamentally reprocessed earth material. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. This study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclear test ("trinitite") and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. The volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.

Problem on estimation of the content of 131I in milk in the ``iodine'' period of the Chernobyl accident

NASA Astrophysics Data System (ADS)

Khrushchinskii, A. A.; Kuten', S. A.; Budevich, N. M.; Minenko, V. F.; Zhukova, O. M.; Luk'yanov, N. K.

2007-11-01

Measurements of the beta-activity of milk, serving as the main source of information on the radioactive contamination of the environment by the iodine isotope 131I, carried out on a DP-100 radiometer in the early post-Chernobyl period (1986) in Belarus, have been mathematically simulated. The results obtained allow the conclusion that the indicated measurements should be analyzed again with consideration for all of the nuclides present in milk.

Quantitative analysis of soil chromatography. I. Water and radionuclide transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reeves, M.; Francis, C.W.; Duguid, J.O.

Soil chromatography has been used successfully to evaluate relative mobilities of pesticides and nuclides in soils. Its major advantage over the commonly used suspension technique is that it more accurately simulates field conditions. Under such conditions the number of potential exchange sites is limited both by the structure of the soil matrix and by the manner in which the carrier fluid moves through this structure. The major limitation of the chromatographic method, however, has been its qualitative nature. This document represents an effort to counter this objection. A theoretical basis is specified for the transport both of the carrier elutingmore » fluid and of the dissolved constituent. A computer program based on this theory is developed which optimizes the fit of theoretical data to experimental data by automatically adjusting the transport parameters, one of which is the distribution coefficient k/sub d/. This analysis procedure thus constitutes an integral part of the soil chromatographic method, by means of which mobilities of nuclides and other dissolved constituents in soils may be quantified.« less

Nuclear Data Sheets for A = 161

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reich C. W.; Reich C.W.

2011-10-01

The experimental results from the various reaction and radioactive decay studies leading to nuclides in the A = 161 mass chain have been reviewed. Nuclides ranging from Sm (Z = 62) through Os (Z = 76) are included, with Os being a new entry based on a recently reported study. These data are summarized and presented, together with adopted level schemes and properties. This work supersedes the previous evaluation (2000Re14) of the data on these nuclides.

SUBGR: A Program to Generate Subgroup Data for the Subgroup Resonance Self-Shielding Calculation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Kang Seog

2016-06-06

The Subgroup Data Generation (SUBGR) program generates subgroup data, including levels and weights from the resonance self-shielded cross section table as a function of background cross section. Depending on the nuclide and the energy range, these subgroup data can be generated by (a) narrow resonance approximation, (b) pointwise flux calculations for homogeneous media; and (c) pointwise flux calculations for heterogeneous lattice cells. The latter two options are performed by the AMPX module IRFFACTOR. These subgroup data are to be used in the Consortium for Advanced Simulation of Light Water Reactors (CASL) neutronic simulator MPACT, for which the primary resonance self-shieldingmore » method is the subgroup method.« less

Simulation of Fast Neutronics in an Accelerator-Driven Sub-Critical Core

NASA Astrophysics Data System (ADS)

Gwyn Rosaire, C.; Sattarov, Akhdiyor; McIntyre, Peter; Tsvetkov, Pavel

2011-10-01

Accelerator-driven subcritical fission in a molten salt core (ADSMS) is being developed as a technology for green nuclear power. ADSMS burns its fertile fuel to completion, it cannot melt down, and it destroys long-lived minor actinides. The ADSMS core consists of a vessel filled with a molten salt eutectic of UCl3 and NaCl. The fast neutronics of ADSMS makes possible two unique benefits: isobreeding, a steady-state equilibrium in which ^238U is bred to ^239Pu and the ^239Pu fissions, and destruction of minor actinides, in which fission of the intermediary nuclides dominates of breeding. Results of simulations of the fast neutronics in the ADSMS core will be presented.

OPERATION CASTLE - Project 4.1 Addendum. Report of the Scientific Director, Exposure of Marshall Islanders and American Military Personnel to Fallout. Extracted Version,

DTIC Science & Technology

Fallout, *Radiation injuries, Exposure(General), Radioactive materials, Nuclear explosion testing, Bikini Atoll, Indigenous population, Marshall ... Islands , Military forces(United States), Villages, Decontamination, Lesions, Therapy, Hematology, Dosimetry

FUNCTION GENERATOR FOR ANALOGUE COMPUTERS

DOEpatents

Skramstad, H.K.; Wright, J.H.; Taback, L.

1961-12-12

An improved analogue computer is designed which can be used to determine the final ground position of radioactive fallout particles in an atomic cloud. The computer determines the fallout pattern on the basis of known wind velocity and direction at various altitudes, and intensity of radioactivity in the mushroom cloud as a function of particle size and initial height in the cloud. The output is then displayed on a cathode-ray tube so that the average or total luminance of the tube screen at any point represents the intensity of radioactive fallout at the geographical location represented by that point. (AEC)

Analysis of Operation Dominic II SMALL BOY radiological and meteorological data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quinn, V.E., Kennedy, N.C.; Steadman, C.R.

1984-08-01

This report describes the Weather Service Nuclear Support Office (WSNSO) analyses of the radiological and meteorological data collected for the Operation Dominic II nuclear test SMALL BOY. Inconsistencies in the radiological data and their resolution are discussed. The methods of estimating fallout-arrival times are discussed. The meteorological situation on D-day and a few days following are described. A comparison of the fallout patterns resulting from these analyses and earlier (1966) analyses is presented. The radiological data used to derive the fallout pattern in this report are tabulated in an appendix. 11 references, 20 figures.

DELFIC: Department of Defense Fallout Prediction System. Volume II. User’s Manual

DTIC Science & Technology

1979-12-31

code, and it strives to include as much of the physics of fallout transport and activity calculation, without resorting to short cuts, as is...fission may be specified. Induced activity in soil material in the fallout and in 2 3BU may be accounted for. Physical and mathematical bases for...900o) *GTo 1.) GO TO 150 ATMR 140 ALT(13=-i003. ATAR 14± GO TO 20O ATNR ±42 15C WRITE(IRISE)ATMSU8 ATMR ±43 160 IGG=IGO+i ATMR 144 C ATMR 145 C CO THE

Analysis of Operation TEAPOT nuclear test BEE radiological and meteorological data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quinn, V.E.

This report describes the Weather Service Nuclear Support Office (WSNSO) analyses of the radiological and meteorological data collected for the BEE nuclear test of Operation TEAPOT. Inconsistencies in the radiological data and their resolution are discussed. The methods of normalizing the radiological data to a standard time and estimating fallout-arrival times are presented. The meteorological situations on event day and the following day are described. A comparison of the WSNSO fallout analysis with an analysis performed in the 1950's is presented. The radiological data used to derive the WSNSO fallout pattern are tabulated in an appendix.

Dispersal, deposition and collective doses after the Chernobyl disaster.

PubMed

Fairlie, Ian

2007-01-01

This article discusses the dispersal, deposition and collective doses of the radioactive fallout from the Chernobyl accident. It explains that, although Belarus, Ukraine and Russia were heavily contaminated by the Chernobyl fallout, more than half of the fallout was deposited outside these countries, particularly in Western Europe. Indeed, about 40 per cent of the surface area of Europe was contaminated. Collective doses are predicted to result in 30,000 to 60,000 excess cancer deaths throughout the northern hemisphere, mostly in western Europe. The article also estimates that the caesium-137 source term was about a third higher than official figures.

Strontium-90 Fallout: Comparison of Rates over Ocean and Land.

PubMed

Volchok, H L; Broecker, W S; Rocco, G G

1966-04-29

Measurements of strontium-90 in waters residing on the Bahama Banks for periods between 12 and 180 days suggest that fallout rates onto these waters are substantially the same as the average rates at all fallout collection stations between 20 degrees and 30 degrees north latitude. If the amount of preciptation on the Bahama Banks is reasonably representative of the oceanic areas in this latitude band, our results support the conclusion that the amount of strontium-90 deposited per unit area of ocean surface is within a factor of 2 of that on land.

The origin of a coarse lithic breccia in the 34 ka caldera-forming Sounkyo eruption, Taisetsu volcano group, central Hokkaido, Japan

NASA Astrophysics Data System (ADS)

Yasuda, Y.; Suzuki-Kamata, K.

2018-05-01

The 34 ka Sounkyo eruption produced 7.6 km3 of tephra ( 5 km3 DRE) as fallout, ignimbrite, and lithic breccia units, forming a small, 2-km-diameter summit caldera in the Taisetsu volcano group, Japan. The Sounkyo eruption products are made up of five eruptive units (SK-A to -E) in proximal regions, corresponding to the distal deposits, a 1- to 2-m-thick pumice fallout and the Px-type ignimbrite up to 220 m thick. The eruption began with a fallout phase, producing unstable low eruption columns during the earlier phase to form a <7-m-thick succession of well-stratified fallouts (SK-A1 and the lower part of the distal fallout). The eruption column reached up to 25 km high (subplinian to plinian) and became more stable at the late of the phase, producing a < 60-m-thick, pumice-dominated fallout (SK-A2 and the upper part of the distal fallout). The second phase, the climax of the Sounkyo eruption, produced a widespread, valley-filling ignimbrite in both proximal and distal regions (SK-B and the Px-type ignimbrite). At the end of the climactic phase, the waning of the eruption led to extensive failure of the walls of the shallow conduit, generating a dense, lithic-rich, low-mobile pyroclastic density current (PDC) to form a >27-m-thick, unstratified and ungraded, coarse lithic breccia (SK-C). The failure in turn choked the conduit, and then the eruption stopped. After a short eruptive hiatus, the eruption resumed with a short-lived fall phase, establishing an eruption column up to 16 km high and producing a <6-m-thick scoria fallout (SK-D). Finally, the eruption ended with the generation of PDCs by eruption column collapse to form a 5- to 15-m-thick ignimbrite in the proximal area (SK-E). Volume relationships between the caldera, ejected magma, and ejected lithic fragments suggest that the caldera was not essentially formed by caldera collapse but, instead, by vent widening as a consequence of explosive erosion and failure of the shallow conduit. The dominance of shallow-origin volcanic rocks in the lithic fraction throughout the Sounkyo eruption products implies the development of a flaring funnel-shaped vent. Hence, the occurrence of lithic breccias within small caldera-forming eruption products does not necessarily reflect either the existence or the timing of caldera collapse, as commonly assumed in literature. Lithic breccias commonly overlie climactic ignimbrite/fallout deposits in small caldera-forming eruptions, and an alternative explanation is that this reflects the collapse of the shallow conduit after an eruption climax, whose walls had been highly fractured and had become unstable owing to progressive erosion.

Cosmogenic Nuclides 10Be-21Ne Burial Dating of Middle Miocene Sedimentary Formation of the Hongliu Valley in Southern Ningxia Basin: A Case of Isotopic Geochronology Study for the Cenozoic Sedimentary Strata

NASA Astrophysics Data System (ADS)

Ma, Y.; Zhang, H.; Wang, W.; Wu, Y.; Pang, J.; Zheng, D.; Li, D.

2015-12-01

Chronology studies for the Cenozoic sedimentary strata based on the magnetostratigraphy cannot afford the unique chronological sequences in the absence of absolute ages from biostratigraphy or volcanic ash chronology. In situ-produced cosmogenic nuclides provide a powerful tool for the sediment dating based on the time-dependent concentration ratio of two nuclides, which are produced in the same mineral but with different half-lives. Thereinto, 10Be-26Al is the most widely used nuclide pairs, of which the available dating range spans the Plio-Pleistocene. But the coupling of 10Be with the stable nuclide 21Ne would significantly improve the burial dating range up to the middle Miocene, which is promising in revolutionizing the chronology study for the Late Cenozoic terrestrial sedimentary sequences. We have applied 10Be-21Ne pair for dating the middle Miocene sediments of the Hongliu Valley in southern Ningxia basin. Two major features of the sediments are involved in our study: (1) sediments originated from the steady erosion of the source area, and (2) the burial depth of our sample after deposition is time dependent due to the gradual accumulation of sediments into basin. The post-burial nuclide production is estimated to be less than 3%, including the contribution by muon interactions, of the total nuclide concentrations measured in our sample. Our 10Be-21Ne analysis demonstrates the age of the burial sample is 12.4(+0.6/-0.4) Ma, and the erosion rate at the source area is 0.26±0.01 cm ka-1. The sample's burial age is consistent with the age constraint set by the Hongliugou Formation (16.7-5.4 Ma) which we collected the sample in. Vertebrate fossils of Platybelodon tongxinensis with an age between 12 and 15 Ma exhumated along with our sample further verifies the reliability of our dating results for the middle Miocene sediments.This study has shown the improved age range of cosmogenic-nuclide burial dating method by incorporating the stable nuclide 21Ne, and has established the feasibility of 10Be-21Ne pair in chronology studies for the Cenozoic sedimentary strata.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holden, N.E., E-mail: holden@bnl.gov

Isotopes and nuclides are important in our everyday life. The general public and most students are never exposed to the concepts of stable and radioactive isotopes/nuclides. The National Nuclear Data Center (NNDC) is involved in an international project to develop a Periodic Table of the Isotopes for the educational community to illustrate the importance of isotopes and nuclides in understanding the world around us. This effort should aid teachers in introducing these concepts to students from the high school to the graduate school level.

WebCN: A web-based computation tool for in situ-produced cosmogenic nuclides

NASA Astrophysics Data System (ADS)

Ma, Xiuzeng; Li, Yingkui; Bourgeois, Mike; Caffee, Marc; Elmore, David; Granger, Darryl; Muzikar, Paul; Smith, Preston

2007-06-01

Cosmogenic nuclide techniques are increasingly being utilized in geoscience research. For this it is critical to establish an effective, easily accessible and well defined tool for cosmogenic nuclide computations. We have been developing a web-based tool (WebCN) to calculate surface exposure ages and erosion rates based on the nuclide concentrations measured by the accelerator mass spectrometry. WebCN for 10Be and 26Al has been finished and published at http://www.physics.purdue.edu/primelab/for_users/rockage.html. WebCN for 36Cl is under construction. WebCN is designed as a three-tier client/server model and uses the open source PostgreSQL for the database management and PHP for the interface design and calculations. On the client side, an internet browser and Microsoft Access are used as application interfaces to access the system. Open Database Connectivity is used to link PostgreSQL and Microsoft Access. WebCN accounts for both spatial and temporal distributions of the cosmic ray flux to calculate the production rates of in situ-produced cosmogenic nuclides at the Earth's surface.

Diffusive mass transport in agglomerated glassy fallout from a near-surface nuclear test

NASA Astrophysics Data System (ADS)

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; Knight, Kim B.; Isselhardt, Brett H.; Matzel, Jennifer E.

2018-02-01

Aerodynamically-shaped glassy fallout is formed when vapor phase constituents from the nuclear device are incorporated into molten carriers (i.e. fallout precursor materials derived from soil or other near-field environmental debris). The effects of speciation and diffusive transport of condensing constituents are not well defined in models of fallout formation. Previously we reported observations of diffuse micrometer scale layers enriched in Na, Fe, Ca, and 235U, and depleted in Al and Ti, at the interfaces of agglomerated fallout objects. Here, we derive the timescales of uranium mass transport in such fallout as it cools from 2500 K to 1500 K by applying a 1-dimensional planar diffusion model to the observed 235U/30Si variation at the interfaces. By modeling the thermal transport between the fireball and the carrier materials, the time of mass transport is calculated to be <0.6 s, <1 s, <2 s, and <3.5 s for fireball yields of 0.1 kt, 1 kt, 10 kt, and 100 kt respectively. Based on the calculated times of mass transport, a maximum temperature of deposition of uranium onto the carrier material of ∼2200 K is inferred (1σ uncertainty of ∼200 K). We also determine that the occurrence of micrometer scale layers of material enriched in relatively volatile Na-species as well as more refractory Ca-species provides evidence for an oxygen-rich fireball based on the vapor pressure of the two species under oxidizing conditions. These results represent the first application of diffusion-based modeling to derive material transport, thermal environments, and oxidation-speciation in near-surface nuclear detonation environments.

The radiological exposure of man from radioactivity in the Baltic Sea.

PubMed

Nielsen, S P; Bengtson, P; Bojanowsky, R; Hagel, P; Herrmann, J; Ilus, E; Jakobson, E; Motiejunas, S; Panteleev, Y; Skujina, A; Suplinska, M

1999-09-30

A radiological assessment has been carried out considering discharges of radioactivity to the Baltic Sea marine environment since 1950. The sources of radioactivity that have been evaluated are atmospheric nuclear-weapons fallout, fallout from the Chernobyl accident in 1986, discharges of radionuclides from Sellafield and La Hague transported into the Baltic Sea, and discharges of radionuclides from nuclear installations located in the Baltic Sea area. Dose rates from man-made radioactivity to individual members of the public (critical groups) have been calculated based on annual intake of seafood and beach occupancy time. The dose rates to individuals from the regions of the Bothnian Sea and Gulf of Finland are predicted to be larger than from any other area in the Baltic Sea due to the pattern of Chernobyl fallout. The dose rates are predicted to have peaked in 1986 at a value of 0.2 mSv year-1. Collective committed doses to members of the public have been calculated based on fishery statistics and predicted concentrations of radionuclides in biota and coastal sediments. The total collective dose from man-made radioactivity in the Baltic Sea is estimated at 2600 manSv, of which approximately two-thirds originate from Chernobyl fallout, approximately one-quarter from atmospheric nuclear-weapons fallout, approximately 8% from European reprocessing facilities, and approximately 0.04% from nuclear installations bordering the Baltic Sea area. An assessment of small-scale dumping of low-level radioactive waste in the Baltic Sea in the 1960s by Sweden and the Soviet Union has showed that doses to man from these activities are negligible. Dose rates and doses from natural radioactivity dominate except for the year 1986 where dose rates to individuals from Chernobyl fallout in some regions of the Baltic Sea approached those from natural radioactivity.

Diffusive mass transport in agglomerated glassy fallout from a near-surface nuclear test

DOE PAGES

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; ...

2017-12-15

Aerodynamically-shaped glassy fallout is formed when vapor phase constituents from the nuclear device are incorporated into molten carriers (i.e. fallout precursor materials derived from soil or other near-field environmental debris). The effects of speciation and diffusive transport of condensing constituents are not well defined in models of fallout formation. Previously we reported observations of diffuse micrometer scale layers enriched in Na, Fe, Ca, and 235U, and depleted in Al and Ti, at the interfaces of agglomerated fallout objects. Here in this paper, we derive the timescales of uranium mass transport in such fallout as it cools from 2500 K tomore » 1500 K by applying a 1-dimensional planar diffusion model to the observed 235U/ 30Si variation at the interfaces. By modeling the thermal transport between the fireball and the carrier materials, the time of mass transport is calculated to be <0.6 s, <1 s, <2 s, and <3.5 s for fireball yields of 0.1 kt, 1 kt, 10 kt, and 100 kt respectively. Based on the calculated times of mass transport, a maximum temperature of deposition of uranium onto the carrier material of ~2200 K is inferred (1σ uncertainty of ~200 K). We also determine that the occurrence of micrometer scale layers of material enriched in relatively volatile Na-species as well as more refractory Ca-species provides evidence for an oxygen-rich fireball based on the vapor pressure of the two species under oxidizing conditions. These results represent the first application of diffusion-based modeling to derive material transport, thermal environments, and oxidation-speciation in near-surface nuclear detonation environments.« less

Diffusive mass transport in agglomerated glassy fallout from a near-surface nuclear test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.

Aerodynamically-shaped glassy fallout is formed when vapor phase constituents from the nuclear device are incorporated into molten carriers (i.e. fallout precursor materials derived from soil or other near-field environmental debris). The effects of speciation and diffusive transport of condensing constituents are not well defined in models of fallout formation. Previously we reported observations of diffuse micrometer scale layers enriched in Na, Fe, Ca, and 235U, and depleted in Al and Ti, at the interfaces of agglomerated fallout objects. Here in this paper, we derive the timescales of uranium mass transport in such fallout as it cools from 2500 K tomore » 1500 K by applying a 1-dimensional planar diffusion model to the observed 235U/ 30Si variation at the interfaces. By modeling the thermal transport between the fireball and the carrier materials, the time of mass transport is calculated to be <0.6 s, <1 s, <2 s, and <3.5 s for fireball yields of 0.1 kt, 1 kt, 10 kt, and 100 kt respectively. Based on the calculated times of mass transport, a maximum temperature of deposition of uranium onto the carrier material of ~2200 K is inferred (1σ uncertainty of ~200 K). We also determine that the occurrence of micrometer scale layers of material enriched in relatively volatile Na-species as well as more refractory Ca-species provides evidence for an oxygen-rich fireball based on the vapor pressure of the two species under oxidizing conditions. These results represent the first application of diffusion-based modeling to derive material transport, thermal environments, and oxidation-speciation in near-surface nuclear detonation environments.« less

Fabrication of simulated DUPIC fuel

NASA Astrophysics Data System (ADS)

Kang, Kweon Ho; Song, Ki Chan; Park, Hee Sung; Moon, Je Sun; Yang, Myung Seung

2000-12-01

Simulated DUPIC fuel provides a convenient way to investigate the DUPIC fuel properties and behavior such as thermal conductivity, thermal expansion, fission gas release, leaching, and so on without the complications of handling radioactive materials. Several pellets simulating the composition and microstructure of DUPIC fuel are fabricated by resintering the powder, which was treated through OREOX process of simulated spent PWR fuel pellets, which had been prepared from a mixture of UO2 and stable forms of constituent nuclides. The key issues for producing simulated pellets that replicate the phases and microstructure of irradiated fuel are to achieve a submicrometre dispersion during mixing and diffusional homogeneity during sintering. This study describes the powder treatment, OREOX, compaction and sintering to fabricate simulated DUPIC fuel using the simulated spent PWR fuel. The homogeneity of additives in the powder was observed after attrition milling. The microstructure of the simulated spent PWR fuel agrees well with the other studies. The leading structural features observed are as follows: rare earth and other oxides dissolved in the UO2 matrix, small metallic precipitates distributed throughout the matrix, and a perovskite phase finely dispersed on grain boundaries.

Cosmogenic-nuclide production by primary cosmic-ray protons

NASA Technical Reports Server (NTRS)

Reedy, R. C.

1985-01-01

The production rates of cosmogenic nuclides were calculated for the primary protons in the galactic and solar cosmic rays. At 1 AU, the long-term average fluxes of solar protons usually produce many more atoms of cosmogenic nuclide than the primary protons in the galactic cosmic rays (GCR). Because the particle fluxes inside meteorites and other large objects in space include many secondary neutrons, the production rates and ratios inside large objects are often very different from those by just the primary GCR protons. It is possible to determine if a small object, was small in space or broken from a meteorite. Because heliospherical modulation and other interactions change the GCR particle spectrum, the production of cosmogenic nuclides by the GCR particles outside the heliosphere will be different from that by modulated GCR primaries.

Kinetics analysis and quantitative calculations for the successive radioactive decay process

NASA Astrophysics Data System (ADS)

Zhou, Zhiping; Yan, Deyue; Zhao, Yuliang; Chai, Zhifang

2015-01-01

The general radioactive decay kinetics equations with branching were developed and the analytical solutions were derived by Laplace transform method. The time dependence of all the nuclide concentrations can be easily obtained by applying the equations to any known radioactive decay series. Taking the example of thorium radioactive decay series, the concentration evolution over time of various nuclide members in the family has been given by the quantitative numerical calculations with a computer. The method can be applied to the quantitative prediction and analysis for the daughter nuclides in the successive decay with branching of the complicated radioactive processes, such as the natural radioactive decay series, nuclear reactor, nuclear waste disposal, nuclear spallation, synthesis and identification of superheavy nuclides, radioactive ion beam physics and chemistry, etc.

Predicted spatio-temporal dynamics of radiocesium deposited onto forests following the Fukushima nuclear accident

PubMed Central

Hashimoto, Shoji; Matsuura, Toshiya; Nanko, Kazuki; Linkov, Igor; Shaw, George; Kaneko, Shinji

2013-01-01

The majority of the area contaminated by the Fukushima Dai-ichi nuclear power plant accident is covered by forest. To facilitate effective countermeasure strategies to mitigate forest contamination, we simulated the spatio-temporal dynamics of radiocesium deposited into Japanese forest ecosystems in 2011 using a model that was developed after the Chernobyl accident in 1986. The simulation revealed that the radiocesium inventories in tree and soil surface organic layer components drop rapidly during the first two years after the fallout. Over a period of one to two years, the radiocesium is predicted to move from the tree and surface organic soil to the mineral soil, which eventually becomes the largest radiocesium reservoir within forest ecosystems. Although the uncertainty of our simulations should be considered, the results provide a basis for understanding and anticipating the future dynamics of radiocesium in Japanese forests following the Fukushima accident. PMID:23995073

40 CFR 129.104 - Benzidine.

Code of Federal Regulations, 2010 CFR

2010-07-01

... subject to contamination solely by fallout from air emissions of benzidine; or to stormwater runoff that... other discharges from areas subject to contamination solely by fallout from air emissions of benzidine... other areas subject to direct contamination by benzidine or benzidine-containing product as a result of...

Doses from external irradiation to Marshall Islanders from Bikini and Enewetak nuclear weapons tests.

PubMed

Bouville, André; Beck, Harold L; Simon, Steven L

2010-08-01

Annual doses from external irradiation resulting from exposure to fallout from the 65 atmospheric nuclear weapons tests conducted in the Marshall Islands at Bikini and Enewetak between 1946 and 1958 have been estimated for the first time for Marshallese living on all inhabited atolls. All tests that deposited fallout on any of the 23 inhabited atolls or separate reef islands have been considered. The methodology used to estimate the radiation doses at the inhabited atolls is based on test- and location-specific radiation survey data, deposition density estimates of 137Cs, and fallout times-of-arrival provided in a companion paper (Beck et al.), combined with information on the radionuclide composition of the fallout at various times after each test. These estimates of doses from external irradiation have been combined with corresponding estimates of doses from internal irradiation, given in a companion paper (Simon et al.), to assess the cancer risks among the Marshallese population (Land et al.) resulting from exposure to radiation from the nuclear weapons tests.

Health effects from fallout.

PubMed

Gilbert, Ethel S; Land, Charles E; Simon, Steven L

2002-05-01

This paper primarily discusses health effects that have resulted from exposures received as a result of above-ground nuclear tests, with emphasis on thyroid disease from exposure to 131I and leukemia and solid cancers from low dose rate external and internal exposure. Results of epidemiological studies of fallout exposures in the Marshall Islands and from the Nevada Test Site are summarized, and studies of persons with exposures similar to those from fallout are briefly reviewed (including patients exposed to 131I for medical reasons and workers exposed externally at low doses and low dose rates). Promising new studies of populations exposed in countries of the former Soviet Union are also discussed and include persons living near the Semipalatinsk Test Site in Kazakhstan, persons exposed as a result of the Chernobyl accident, and persons exposed as a result of operations of the Mayak Nuclear Plant in the Russian Federation. Very preliminary estimates of cancer risks from fallout doses received by the United States population are presented.

Comments on Strontium-90 in Surface Air in Relation to Stratospheric Fallout.

NASA Astrophysics Data System (ADS)

Rangarajan, C.; Eapen, C. D.

1984-08-01

The time variation of the spring peak of stratospheric fallout is examined with surface air data of Cs-137 concentrations from about 30 stations in the zone 9 to 75°N and 80°W to 115°E. This study is likely to be more realistic than one derived from data confined to a particular meridian, such as the United States 80th meridian fallout sampling network. It is seen from an examination of the data that the spring peak of stratospheric fallout is progressively delayed with increasing latitude from 9 to 50°N. At latitudes beyond 50°N, no clear trend can be postulated due to limited data. The reason for this progressive delay in the appearance of the spring peak is likely to be due to changes in the circulation pattern, rather than variations in precipitation scavenging, as regions with different distributions of rainfall have the same progressive delay in the spring peak.

Web-Enabled Optoelectronic Particle-Fallout Monitor

NASA Technical Reports Server (NTRS)

Lineberger, Lewis P.

2008-01-01

A Web-enabled optoelectronic particle- fallout monitor has been developed as a prototype of future such instruments that (l) would be installed in multiple locations for which assurance of cleanliness is required and (2) could be interrogated and controlled in nearly real time by multiple remote users. Like prior particle-fallout monitors, this instrument provides a measure of particles that accumulate on a surface as an indication of the quantity of airborne particulate contaminants. The design of this instrument reflects requirements to: Reduce the cost and complexity of its optoelectronic sensory subsystem relative to those of prior optoelectronic particle fallout monitors while maintaining or improving capabilities; Use existing network and office computers for distributed display and control; Derive electric power for the instrument from a computer network, a wall outlet, or a battery; Provide for Web-based retrieval and analysis of measurement data and of a file containing such ancillary data as a log of command attempts at remote units; and Use the User Datagram Protocol (UDP) for maximum performance and minimal network overhead.

Pu isotopes in soils collected downwind from Lop Nor: regional fallout vs. global fallout.

PubMed

Bu, Wenting; Ni, Youyi; Guo, Qiuju; Zheng, Jian; Uchida, Shigeo

2015-07-17

For the first time, soil core samples from the Jiuquan region have been analyzed for Pu isotopes for radioactive source identification and radiological assessment. The Jiuquan region is in downwind from the Lop Nor Chinese nuclear test (CNT) site. The high Pu inventories (13 to 546 Bq/m(2)) in most of the sampling locations revealed that this region was heterogeneously contaminated by the regional fallout Pu from the CNTs. The contributions of the CNTs to the total Pu in soils were estimated to be more than 40% in most cases. The (240)Pu/(239)Pu atom ratios in the soils ranged from 0.059 to 0.186 with an inventory-weighted average of 0.158, slightly lower than that of global fallout. This atom ratio could be considered as a mixed fingerprint of Pu from the CNTs. In addition, Pu in soils of Jiuquan region had a faster downward migration rate compared with other investigated places in China.

Pu isotopes in soils collected downwind from Lop Nor: regional fallout vs. global fallout

PubMed Central

Bu, Wenting; Ni, Youyi; Guo, Qiuju; Zheng, Jian; Uchida, Shigeo

2015-01-01

For the first time, soil core samples from the Jiuquan region have been analyzed for Pu isotopes for radioactive source identification and radiological assessment. The Jiuquan region is in downwind from the Lop Nor Chinese nuclear test (CNT) site. The high Pu inventories (13 to 546 Bq/m2) in most of the sampling locations revealed that this region was heterogeneously contaminated by the regional fallout Pu from the CNTs. The contributions of the CNTs to the total Pu in soils were estimated to be more than 40% in most cases. The 240Pu/239Pu atom ratios in the soils ranged from 0.059 to 0.186 with an inventory-weighted average of 0.158, slightly lower than that of global fallout. This atom ratio could be considered as a mixed fingerprint of Pu from the CNTs. In addition, Pu in soils of Jiuquan region had a faster downward migration rate compared with other investigated places in China. PMID:26184740

Natural Environmental Hazards Reflected in High-Altitude Patagonian Lake Sediments (lake Caviahue, Argentina)

NASA Astrophysics Data System (ADS)

Müller, Anne; Scharf, Burkhard; von Tümpling, Wolf; Pirrung, Michael

2009-03-01

Two 6-m long sediment cores drilled in the two basins of Lake Caviahue give new evidence of the impact of natural hazards such as ash fallouts linked to nearby volcanic eruptions in the ecologically sensitive environment of the high-altitude region of the Argentinan Patagonian Andes. The two cores show distinct signals of changes in autochthonous productivity and terrigenous input into the lake from ash fallout as well as from river load and shore erosion. Multiproxy records of the sediments indicate whether these changes can be related to volcanic activity. High values of magnetic susceptibility in the cores reflect periods of basaltic ash fallouts during eruptions of the nearby Copahue Volcano. The southern basin is located in the prevalent direction of ash fallouts and has been affected by these volcanic inputs more intensely than the northern basin of the lake. In contrast, sedimentation and authochthonous productivity in the northern basin are strongly affected by fluvial inputs such as suspended river load and acidic stream waters.

Natural Environmental Hazards Reflected in High-Altitude Patagonian Lake Sediments (Lake Caviahue, Argentina)

NASA Astrophysics Data System (ADS)

Mueller, A.; Pirrung, M.; Scharf, B.; von Tuempling, W.

2007-05-01

Two 6-m long sediment cores drilled in the two basins of Lake Caviahue give new evidence of the impact of natural hazards such as ash fallouts linked to nearby volcanic eruptions in the ecologically sensitive environment of the high-altitude region of the Argentinan Patagonian Andes. The two cores show distinct signals of changes in autochthonous productivity and terrigenous input into the lake from ash fallout, river load and shore erosion. Multiproxy records of the sediments indicate whether these changes can be related to volcanic activity. High values of magnetic susceptibility in the cores reflect periods of basaltic ash fallouts during eruptions of the nearby Copahue volcano. The southern basin is located in the prevalent direction of ash fallouts and has been affected by these volcanic inputs more intensely than the northern basin of the lake. In contrast, sedimentation and authochthonous productivity in the northern basin are strongly affected by fluvial inputs such as suspended river load and acidic stream waters.

Correction

NASA Astrophysics Data System (ADS)

1996-04-01

Fallout of volcanic ash to the deep South China Sea induced by the 1991 eruption of Mount Pinatubo (Philippines): Correction Geology, v. 23, p. 885 888 (October 1995) On p. 885, the last sentence of the Introduction should be: Here we report the first in situ record of a submarine fallout of volcanic ash following one of the largest magnitude subaerial eruptions of this century, the June 15, 1991, paroxysmal explosion of Mount Pinatubo (lat 15.148, long 120.358) in the Philippines. The first sentence under the head SUBMARINE FALLOUT MONITORING AND COMPOSITION should be: Fallout of Pinatubo tephra was recorded by fully automated collection devices (sediment traps) moored in 1190 and 3730 m water depth at 14.608N, 115.108E (Fig. 1). On p. 886, center column, the second sentence under the head LINKS TO SUBAERIAL ASH-PLUME MOVEMENT should be: Ash was ejected to a maximum altitude of 35 40 km, and at about14:20 the cloud spread out laterally into a giant umbrella region between 25 and 30 km altitude.

Key Response Planning Factors for the Aftermath of Nuclear Terrorism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buddemeier, B R; Dillon, M B

Despite hundreds of above-ground nuclear tests and data gathered from Hiroshima and Nagasaki, the effects of a ground-level, low-yield nuclear detonation in a modern urban environment are still the subject of considerable scientific debate. Extensive review of nuclear weapon effects studies and discussions with nuclear weapon effects experts from various federal agencies, national laboratories, and technical organizations have identified key issues and bounded some of the unknowns required to support response planning for a low-yield, ground-level nuclear detonation in a modern U.S. city. This study, which is focused primarily upon the hazards posed by radioactive fallout, used detailed fallout predictionsmore » from the advanced suite of three-dimensional (3-D) meteorology and plume/fallout models developed at Lawrence Livermore National Laboratory (LLNL), including extensive global Key Response Planning Factors for the Aftermath of Nuclear Terrorism geographical and real-time meteorological databases to support model calculations. This 3-D modeling system provides detailed simulations that account for complex meteorology and terrain effects. The results of initial modeling and analysis were presented to federal, state, and local working groups to obtain critical, broad-based review and feedback on strategy and messaging. This effort involved a diverse set of communities, including New York City, National Capitol Regions, Charlotte, Houston, Portland, and Los Angeles. The largest potential for reducing casualties during the post-detonation response phase comes from reducing exposure to fallout radiation. This can be accomplished through early, adequate sheltering followed by informed, delayed evacuation.B The response challenges to a nuclear detonation must be solved through multiple approaches of public education, planning, and rapid response actions. Because the successful response will require extensive coordination of a large number of organizations, supplemented by appropriate responses by local responders and the general population within the hazard zones, regional planning is essential to success. The remainder of this Executive Summary provides summary guidance for response planning in three areas: (1) Public Protection Strategy details the importance of early, adequate shelter followed by informed evacuation. (2) Responder Priorities identify how to protect response personnel, perform regional situational assessment, and support public safety. (3) Key Planning Considerations refute common myths and provide important information on planning how to respond in the aftermath of nuclear terrorism.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holden, N. E.

We found that isotopes and nuclides are important in our everyday life. The general public and most students are never exposed to the concepts of stable and radioactive isotopes/nuclides. The National Nuclear Data Center (NNDC) is involved in an international project to develop a Periodic Table of the Isotopes for the educational community to illustrate the importance of isotopes and nuclides in understanding the world around us. Our effort should aid teachers in introducing these concepts to students from the high school to the graduate school level.

Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.

In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamicmore » fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device ( 235U/ 238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO 2 is found to be relatively invariable across the samples and interfaces (~3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a continuous condensation process may also be occurring. Lastly, these fallout formation processes deviate from historical models of fallout formation, and have not been previously recognized in the literature.« less

Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

NASA Astrophysics Data System (ADS)

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; Knight, Kim B.; Isselhardt, Brett H.; Matzel, Jennifer E.; Weber, Peter K.; Prussin, Stan G.; Hutcheon, Ian D.

2017-03-01

In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamic fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device (235U/238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO2 is found to be relatively invariable across the samples and interfaces (∼3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a continuous condensation process may also be occurring. These fallout formation processes deviate from historical models of fallout formation, and have not been previously recognized in the literature.

Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

DOE PAGES

Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; ...

2016-10-29

In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamicmore » fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device ( 235U/ 238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO 2 is found to be relatively invariable across the samples and interfaces (~3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a continuous condensation process may also be occurring. Lastly, these fallout formation processes deviate from historical models of fallout formation, and have not been previously recognized in the literature.« less

The early thermal evolution of Mars

NASA Astrophysics Data System (ADS)

Bhatia, G. K.; Sahijpal, S.

2016-01-01

Hf-W isotopic systematics of Martian meteorites have provided evidence for the early accretion and rapid core formation of Mars. We present the results of numerical simulations performed to study the early thermal evolution and planetary scale differentiation of Mars. The simulations are confined to the initial 50 Myr (Ma) of the formation of solar system. The accretion energy produced during the growth of Mars and the decay energy due to the short-lived radio-nuclides 26Al, 60Fe, and the long-lived nuclides, 40K, 235U, 238U, and 232Th are incorporated as the heat sources for the thermal evolution of Mars. During the core-mantle differentiation of Mars, the molten metallic blobs were numerically moved using Stoke's law toward the center with descent velocity that depends on the local acceleration due to gravity. Apart from the accretion and the radioactive heat energies, the gravitational energy produced during the differentiation of Mars and the associated heat transfer is also parametrically incorporated in the present work to make an assessment of its contribution to the early thermal evolution of Mars. We conclude that the accretion energy alone cannot produce widespread melting and differentiation of Mars even with an efficient consumption of the accretion energy. This makes 26Al the prime source for the heating and planetary scale differentiation of Mars. We demonstrate a rapid accretion and core-mantle differentiation of Mars within the initial ~1.5 Myr. This is consistent with the chronological records of Martian meteorites.

Soil redistribution model for undisturbed and cultivated sites based on Chernobyl-derived cesium-137 fallout.

PubMed

Hrachowitz, Markus; Maringer, Franz-Josef; Steineder, Christian; Gerzabek, Martin H

2005-01-01

Measurements of 137Cs fallout have been used in combination with a range of conversion models for the investigation of soil relocation mechanisms and sediment budgets in many countries for more than 20 yr. The objective of this paper is to develop a conversion model for quantifying soil redistribution, based on Chernobyl-derived 137Cs. The model is applicable on uncultivated as well as on cultivated sites, taking into account temporal changes in the 137Cs depth distribution pattern as well as tillage-induced 137Cs dilution effects. The main idea of the new model is the combination of a modified exponential model describing uncultivated soil with a Chapman distribution based model describing cultivated soil. The compound model subsequently allows a dynamic description of the Chernobyl derived 137Cs situation in the soil and its change, specifically migration and soil transport processes over the course of time. Using the suggested model at the sampling site in Pettenbach, in the Austrian province of Oberösterreich 137Cs depth distributions were simulated with a correlation coefficient of 0.97 compared with the measured 137Cs depth profile. The simulated rates of soil distribution at different positions at the sampling site were found to be between 27 and 60 Mg ha(-1) yr(-1). It was shown that the model can be used to describe the temporal changes of 137Cs depth distributions in cultivated as well as uncultivated soils. Additionally, the model allows to quantify soil redistribution in good correspondence with already existing models.

40 CFR 129.102 - Endrin.

Code of Federal Regulations, 2010 CFR

2010-07-01

... or other discharges from areas subject to contamination solely by fallout from air emissions of... from areas subject to contamination solely by fallout from air emissions of endrin; or to storm-water... contamination by endrin as a result of the manufacturing process, including but not limited to: (1) Stormwater...

40 CFR 129.103 - Toxaphene.

Code of Federal Regulations, 2010 CFR

2010-07-01

... contamination solely by fallout from air emissions of toxaphene; or to stormwater runoff that exceeds that from... contamination solely by fallout from air emissions of toxaphene; or to stormwater runoff that exceeds that from... and other areas which are subject to direct contamination by toxaphene as a result of the...

An application of excess lead-210 analysis for the study of fine sediment connectivity in a Mediterranean mountain basin with badlands, the Vallcebre research catchments

NASA Astrophysics Data System (ADS)

Moreno de las Heras, Mariano; Gallart, Francesc; Latron, Jérôme; Martínez-Carreras, Núria; Ferrer, Laura; Estrany, Joan

2017-04-01

Analysis of sediment dynamics in Mediterranean environments is fundamental to basin management, particularly for mountain catchments with badlands, which affect water bodies and freshwater ecosystems. Connectivity has emerged in Environmental and Earth Sciences as an evolution of the sediment delivery concept, providing a useful framework for understanding how sediments are transferred between geomorphic zones of the catchment. This study explores the feasibility of excess lead-210 (210Pbex) to analyse sediment connectivity in a 4-km2 Mediterranean mountain basin with badlands (the Vallcebre research catchments, Eastern Pyrenees) by applying simple 210Pbex mass-balance models for hypothesis generation and experimental testing in the field. Badland surfaces in the basin are weathered by freezing during the winter and are further eroded in summer by the effect of high-intensity storms. The eroded sediments may remain deposited within the catchment streams from months to years. Application of 210Pbex balance models in our basin proposes: (i) a saw-tooth seasonal pattern of badland surface 210Pbex activities (increasing from October to May, and depleted in summer) and (ii) a downstream increase in sediment activity due to fallout lead-210 accumulation in streambed sediment deposits. Both deposited and suspended sediments collected at the Vallcebre catchments showed, in general, low sediment 210Pbex concentrations, illustrating their fresh-rock origin at the badland sites, but also hampering the understanding of sediment 210Pbex patterns due to high measurement uncertainty (particularly for sediments with d50>20µm) and to strong dependence on sediment sampling methodology. Suspended sediment 210Pbex activity reproduced the simulated seasonal activity patterns for the badland surfaces. Contrary to the in-stream transit increases of sediment 210Pbex activity that were predicted by our model simulations, fallout lead-210 concentrations in the suspended sediments decreased towards the basin outlet, suggesting that fine sediment flushing by flooding prevented 210Pbex accumulation in the coarser streambed sediment deposits. These results indicate a high fine-sediment connectivity between the badlands, streams and basin outlet of the Vallcebre catchments, as well as the sequestration and fast transmission of fallout lead-210 by the finest and most dynamic fraction of sediments.

VERA Core Simulator Methodology for PWR Cycle Depletion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kochunas, Brendan; Collins, Benjamin S; Jabaay, Daniel

2015-01-01

This paper describes the methodology developed and implemented in MPACT for performing high-fidelity pressurized water reactor (PWR) multi-cycle core physics calculations. MPACT is being developed primarily for application within the Consortium for the Advanced Simulation of Light Water Reactors (CASL) as one of the main components of the VERA Core Simulator, the others being COBRA-TF and ORIGEN. The methods summarized in this paper include a methodology for performing resonance self-shielding and computing macroscopic cross sections, 2-D/1-D transport, nuclide depletion, thermal-hydraulic feedback, and other supporting methods. These methods represent a minimal set needed to simulate high-fidelity models of a realistic nuclearmore » reactor. Results demonstrating this are presented from the simulation of a realistic model of the first cycle of Watts Bar Unit 1. The simulation, which approximates the cycle operation, is observed to be within 50 ppm boron (ppmB) reactivity for all simulated points in the cycle and approximately 15 ppmB for a consistent statepoint. The verification and validation of the PWR cycle depletion capability in MPACT is the focus of two companion papers.« less

Soft-Rotator Coupled Channels Global Optical Potential for A=24-122 Mass Region Nuclides up to 200-MeV Incident Nucleon Energies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soukhovitski, Efrem Sh.; Chiba, Satoshi; Lee, Jeong-Yeon

2005-05-24

A coupled-channels optical model with a coupling scheme based on nuclear wave functions of the soft-rotator model was applied to analyze experimental nucleon-nucleus interaction data for even-even nuclides with mass number A=24-122. We found that all the available data (total cross sections, angular distributions of elastically and inelastically scattered nucleons, and reaction cross sections) for these nuclides can be described to a good accuracy using an optical potential having smooth dependencies of potential values, radii, and diffuseness on the mass number. The individual properties of the target nuclides are accounted for by individuality of the nuclear Hamiltonian parameters, adjusted tomore » reproduce the low-lying collective level structure, Fermi energies, and deformation parameters.« less

Development and Application of a Model of Fallout Shelter Stay Times.

DTIC Science & Technology

1978-12-29

post-attack environment is a disaster, and that human response to a nuclear disaster is an extropolation of human response to natural disasters...Soviet reaction to a nuclear disaster . This technique is not limited to fallout shelter studies. If an appropriate data base exists, subjects such as

40 CFR 129.101 - DDT, DDD and DDE.

Code of Federal Regulations, 2010 CFR

2010-07-01

... stormwater runoff or other discharges from areas subject to contamination solely by fallout from air... other discharges from areas subject to contamination solely by fallout from air emissions of DDT; or to... subject to direct contamination by DDT as a result of the manufacturing process, including but not limited...

Personal and Family Survival. Civil Defense Adult Education; Teacher's Manual.

ERIC Educational Resources Information Center

Office of Civil Defense (DOD), Washington, DC.

A manual intended as an instructor's aid in presenting a Civil Defense Adult Education Course is presented. It contains 10 lesson plans: Course Introduction, Modern Weapons and Radioactive Fallout (Effects), Modern Weapons and Radioactive Fallout (Protection), National Civil Defense Program, National Shelter Program (Community Shelters), National…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van der Stricht, E.; Vaninbroukx, R.; De Visscher, M.

The results of measurements of fall-out at Mol and in the Belgian Congo are given for July to December 1959. The air activity, total fall-out, and determinations of Sr/sup 9//sup 0/, Sr/sup 8//sup 9/, and Cs/sup 1//sup 3//sup 7/ are tabulated. Meteorological data are also given. (J.S.R.)

Impact of Nuclear Data Uncertainties on Calculated Spent Fuel Nuclide Inventories and Advanced NDA Instrument Response

DOE PAGES

Hu, Jianwei; Gauld, Ian C.

2014-12-01

The U.S. Department of Energy’s Next Generation Safeguards Initiative Spent Fuel (NGSI-SF) project is nearing the final phase of developing several advanced nondestructive assay (NDA) instruments designed to measure spent nuclear fuel assemblies for the purpose of improving nuclear safeguards. Current efforts are focusing on calibrating several of these instruments with spent fuel assemblies at two international spent fuel facilities. Modelling and simulation is expected to play an important role in predicting nuclide compositions, neutron and gamma source terms, and instrument responses in order to inform the instrument calibration procedures. As part of NGSI-SF project, this work was carried outmore » to assess the impacts of uncertainties in the nuclear data used in the calculations of spent fuel content, radiation emissions and instrument responses. Nuclear data is an essential part of nuclear fuel burnup and decay codes and nuclear transport codes. Such codes are routinely used for analysis of spent fuel and NDA safeguards instruments. Hence, the uncertainties existing in the nuclear data used in these codes affect the accuracies of such analysis. In addition, nuclear data uncertainties represent the limiting (smallest) uncertainties that can be expected from nuclear code predictions, and therefore define the highest attainable accuracy of the NDA instrument. This work studies the impacts of nuclear data uncertainties on calculated spent fuel nuclide inventories and the associated NDA instrument response. Recently developed methods within the SCALE code system are applied in this study. The Californium Interrogation with Prompt Neutron instrument was selected to illustrate the impact of these uncertainties on NDA instrument response.« less

Impact of Nuclear Data Uncertainties on Calculated Spent Fuel Nuclide Inventories and Advanced NDA Instrument Response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Jianwei; Gauld, Ian C.

The U.S. Department of Energy’s Next Generation Safeguards Initiative Spent Fuel (NGSI-SF) project is nearing the final phase of developing several advanced nondestructive assay (NDA) instruments designed to measure spent nuclear fuel assemblies for the purpose of improving nuclear safeguards. Current efforts are focusing on calibrating several of these instruments with spent fuel assemblies at two international spent fuel facilities. Modelling and simulation is expected to play an important role in predicting nuclide compositions, neutron and gamma source terms, and instrument responses in order to inform the instrument calibration procedures. As part of NGSI-SF project, this work was carried outmore » to assess the impacts of uncertainties in the nuclear data used in the calculations of spent fuel content, radiation emissions and instrument responses. Nuclear data is an essential part of nuclear fuel burnup and decay codes and nuclear transport codes. Such codes are routinely used for analysis of spent fuel and NDA safeguards instruments. Hence, the uncertainties existing in the nuclear data used in these codes affect the accuracies of such analysis. In addition, nuclear data uncertainties represent the limiting (smallest) uncertainties that can be expected from nuclear code predictions, and therefore define the highest attainable accuracy of the NDA instrument. This work studies the impacts of nuclear data uncertainties on calculated spent fuel nuclide inventories and the associated NDA instrument response. Recently developed methods within the SCALE code system are applied in this study. The Californium Interrogation with Prompt Neutron instrument was selected to illustrate the impact of these uncertainties on NDA instrument response.« less

Cosmogenic nuclide production rates as a function of latitude and altitude calculated via a physics based model and excitation functions

NASA Astrophysics Data System (ADS)

Argento, D.; Reedy, R. C.; Stone, J. O.

2012-12-01

Cosmogenic nuclides have been used to develop a set of tools critical to the quantification of a wide range of geomorphic and climatic processes and events (Dunai 2010). Having reliable absolute measurement methods has had great impact on research constraining ice age extents as well as providing important climatic data via well constrained erosion rates, etc. Continuing to improve CN methods is critical for these sciences. While significant progress has been made in the last two decades to reduce uncertainties (Dunai 2010; Gosse & Phillips 2001), numerous aspects still need to be refined in order to achieve the analytic resolution desired by glaciologists and geomorphologists. In order to investigate the finer details of the radiation responsible for cosmogenic nuclide production, we have developed a physics based model which models the radiation cascade of primary and secondary cosmic-rays through the atmosphere. In this study, a Monte Carlo method radiation transport code, MCNPX, is used to model the galactic cosmic-ray (GCR) radiation impinging on the upper atmosphere. Beginning with a spectrum of high energy protons and alpha particles at the top of the atmosphere, the code tracks the primary and resulting secondary particles through a model of the Earth's atmosphere and into the lithosphere. Folding the neutron and proton flux results with energy dependent cross sections for nuclide production provides production rates for key cosmogenic nuclides (Argento et al. 2012, in press; Reedy 2012, in press). Our initial study for high latitude shows that nuclides scale at different rates for each nuclide (Argento 2012, in press). Furthermore, the attenuation length for each of these nuclide production rates increases with altitude, and again, they increase at different rates. This has the consequence of changing the production rate ratio as a function of altitude. The earth's geomagnetic field differentially filters low energy cosmic-rays by deflecting them away. This effect is strongest at the equator. This filtering reduces the total number of particles, and also biases the spectrum towards the higher energies. This effect is known to generally increase the attenuation length of production with altitude at the same time reducing the overall production rate. Our model now extends from high latitude to the equator. We expect the production rates, attenuation lengths and production ratios to also be functions of latitude. Our radiation model results are being analyzed and nuclide production rate results will be presented at the conference.

Shift Verification and Validation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pandya, Tara M.; Evans, Thomas M.; Davidson, Gregory G

2016-09-07

This documentation outlines the verification and validation of Shift for the Consortium for Advanced Simulation of Light Water Reactors (CASL). Five main types of problems were used for validation: small criticality benchmark problems; full-core reactor benchmarks for light water reactors; fixed-source coupled neutron-photon dosimetry benchmarks; depletion/burnup benchmarks; and full-core reactor performance benchmarks. We compared Shift results to measured data and other simulated Monte Carlo radiation transport code results, and found very good agreement in a variety of comparison measures. These include prediction of critical eigenvalue, radial and axial pin power distributions, rod worth, leakage spectra, and nuclide inventories over amore » burn cycle. Based on this validation of Shift, we are confident in Shift to provide reference results for CASL benchmarking.« less

Cosmogenic Nuclides Study of Large Iron Meteorites

NASA Astrophysics Data System (ADS)

Hutzler, A.; Smith, T.; Rochette, P.; Bourles, D. L.; Leya, I.; Gattacceca, J.

2014-09-01

Six large iron meteorites were selected (Saint-Aubin, Mont-Dieu, Caille, Morasko, Agoudal, and Gebel Kamil). We measured stable and radiogenic cosmogenic nuclides, to study pre-atmospheric size, cosmic-ray exposure ages and terrestrial ages.

Understanding Contamination; Twenty Years of Simulating Radiological Contamination

DOE Office of Scientific and Technical Information (OSTI.GOV)

Emily Snyder; John Drake; Ryan James

A wide variety of simulated contamination methods have been developed by researchers to reproducibly test radiological decontamination methods. Some twenty years ago a method of non-radioactive contamination simulation was proposed at the Idaho National Laboratory (INL) that mimicked the character of radioactive cesium and zirconium contamination on stainless steel. It involved baking the contamination into the surface of the stainless steel in order to 'fix' it into a tenacious, tightly bound oxide layer. This type of contamination was particularly applicable to nuclear processing facilities (and nuclear reactors) where oxide growth and exchange of radioactive materials within the oxide layer becamemore » the predominant model for material/contaminant interaction. Additional simulation methods and their empirically derived basis (from a nuclear fuel reprocessing facility) are discussed. In the last ten years the INL, working with the Defense Advanced Research Projects Agency (DARPA) and the National Homeland Security Research Center (NHSRC), has continued to develop contamination simulation methodologies. The most notable of these newer methodologies was developed to compare the efficacy of different decontamination technologies against radiological dispersal device (RDD, 'dirty bomb') type of contamination. There are many different scenarios for how RDD contamination may be spread, but the most commonly used one at the INL involves the dispersal of an aqueous solution containing radioactive Cs-137. This method was chosen during the DARPA projects and has continued through the NHSRC series of decontamination trials and also gives a tenacious 'fixed' contamination. Much has been learned about the interaction of cesium contamination with building materials, particularly concrete, throughout these tests. The effects of porosity, cation-exchange capacity of the material and the amount of dirt and debris on the surface are very important factors. The interaction of the contaminant/substrate with the particular decontamination technology is also very important. Results of decontamination testing from hundreds of contaminated coupons have lead to certain conclusions about the contamination and the type of decontamination methods being deployed. A recent addition to the DARPA initiated methodology simulates the deposition of nuclear fallout. This contamination differs from previous tests in that it has been developed and validated purely to simulate a 'loose' type of contamination. This may represent the first time that a radiologically contaminated 'fallout' stimulant has been developed to reproducibly test decontamination methods. While no contaminant/methodology may serve as a complete example of all aspects that could be seen in the field, the study of this family of simulation methods provides insight into the nature of radiological contamination.« less

Reprocessing system with nuclide separation based on chromatography in hydrochloric acid solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Tatsuya; Tachibana, Yu; Koyama, Shi-ichi

2013-07-01

We have proposed the reprocessing system with nuclide separation processes based on the chromatographic technique in the hydrochloric acid solution system. Our proposed system consists of the dissolution process, the reprocessing process, the minor actinide separation process, and nuclide separation processes. In the reprocessing and separation processes, the pyridine resin is used as a main separation media. It was confirmed that the dissolution in the hydrochloric acid solution is easily achieved by the plasma voloxidation and by the addition of oxygen peroxide into the hydrochloric acid solution.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chadwick, M. B.; Capote, R.; Trkov, A.

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies - 16O, 56Fe, 235;8U and 239Pu - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality.

Fallout from the Chernobyl nuclear disaster and congenital malformations in Europe.

PubMed

Hoffmann, W

2001-01-01

Investigators estimate that the population exposure that resulted from the Chernobyl fallout is in the range of natural background radiation for most European countries. Given current radiobiologic knowledge, health effects-if any-would not be measurable with epidemiologic tools. In several independent reports, however, researchers have described isolated peaks in the prevalence of congenital malformations in the cohort conceived immediately after onset of the fallout. The consistency of the time pattern and the specific types of malformation raise concern about their significance. In this study, the author summarizes findings from Turkey, Belarus, Croatia, Finland, Germany, and other countries, and implications for radiation protection and public health issues are discussed.

A survey of radioactive fallout data in Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

DePhillips, M.P.

1995-10-23

Considerable attention has been directed by the scientific community to assessing the levels and fate of radionuclides in Arctic ecosystems. The following text and tables present available data and discussion of radionuclide fallout in Alaska. A literature search of 23 on-line databases (Table 1) using Alaska, Strontium (Sr), Cesium (Cs), Plutonium (Pu) and Radionuclide as constraint terms responded with 177 possible citations. After eliminating duplicate citations, 31 articles were available: 17 were relevant to the subject matter; the remainder addressed geologic issues. All of the cited literature addressed {sup 137}Cs, {sup 90}Sr and {sup 239,240}Pu as a result of radionuclidemore » fallout from nuclear testing or accidental release.« less

Distribution of neptunium and plutonium in New Mexico lichen samples ( Usnea arizonica) contaminated by atmospheric fallout

DOE PAGES

Oldham, Jr., Warren J.; Hanson, Susan K.; Lavelle, Kevin B.; ...

2015-08-30

In this study, the concentrations of 237Np, 239Pu and 240Pu were determined in lichen samples ( Usnea arizonica) that were collected from ten locations in New Mexico between 2011 and 2013 using isotope dilution inductively-coupled plasma mass spectrometry (ID-ICP-MS). The observed isotopic ratios for 237Np/ 239Pu and 240Pu/ 239Pu indicate trace contamination from global and regional fallout (e.g. Trinity test and atmospheric testing at the Nevada Test Site). The fact that actinide contamination is detected in recent lichen collections suggests continuous re-suspension of fallout radionuclides even 50 years after ratification of the Limited Test Ban Treaty.

Inter-laboratory comparisons of short-lived gamma-emitting radionuclides in nuclear reactor water.

PubMed

Klemola, S K

2008-01-01

Inter-laboratory comparisons of gamma-emitting nuclides in nuclear power plant coolant water have been carried out in Finland since 1994. The reactor water samples are taken and prepared by one of the two nuclear power plants and delivered to the participants. Since all the participants get their sample within just a few hours it has been possible to analyse and compare results of nuclides with half-lives shorter than 1h. The total number of short-lived nuclides is 26. All the main nuclides are regularly identified and the activities have been obtained with reasonable accuracy throughout the years. The overall deviation of the results has decreased in 13 years. The effects of true coincidence summing and discrepancies in nuclear data have been identified as potential sources of remaining discrepancies. All the participants have found this type of comparison very useful.

Cesium 137-Its applications for understanding soil redistribution and deposition patterns on the landscape

USDA-ARS?s Scientific Manuscript database

In the 1960s research began on the application of fallout radionuclides to determine sediment deposition and soil redistribution rates and patterns in agricultural and natural ecosystems. This research was based on the use of fallout 137Cesium (137Cs) from nuclear weapon tests deposited worldwide d...

How to Make the 20-cent Fallout Meter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meade, Roger Allen; Rodriguez, Serena R.; Alvarez, Luis

Nobel Prize winner Luis Alvarez published an article on how to build a homemade fallout meter in the November 12, 1961, issue of the Sunday supplement This Week Magazine. A yellowed copy of the article was recently found in the files of the Radiochemistry Group, C-NR, and is reproduced below in its original form.

7 CFR 760.7 - Other requirements for affected farmers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... residue of a pesticide, a chemical, or a toxic substance or was contaminated by nuclear radiation or... by nuclear radiation or fallout. (3) The contamination of his milk was not otherwise his fault. (c..., chemicals, or toxic substances or contamination from nuclear radiation or fallout from his milk as soon as...

7 CFR 760.7 - Other requirements for affected farmers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... residue of a pesticide, a chemical, or a toxic substance or was contaminated by nuclear radiation or... by nuclear radiation or fallout. (3) The contamination of his milk was not otherwise his fault. (c..., chemicals, or toxic substances or contamination from nuclear radiation or fallout from his milk as soon as...

7 CFR 760.7 - Other requirements for affected farmers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... residue of a pesticide, a chemical, or a toxic substance or was contaminated by nuclear radiation or... by nuclear radiation or fallout. (3) The contamination of his milk was not otherwise his fault. (c..., chemicals, or toxic substances or contamination from nuclear radiation or fallout from his milk as soon as...

7 CFR 760.7 - Other requirements for affected farmers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... residue of a pesticide, a chemical, or a toxic substance or was contaminated by nuclear radiation or... by nuclear radiation or fallout. (3) The contamination of his milk was not otherwise his fault. (c..., chemicals, or toxic substances or contamination from nuclear radiation or fallout from his milk as soon as...

7 CFR 760.7 - Other requirements for affected farmers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... residue of a pesticide, a chemical, or a toxic substance or was contaminated by nuclear radiation or... by nuclear radiation or fallout. (3) The contamination of his milk was not otherwise his fault. (c..., chemicals, or toxic substances or contamination from nuclear radiation or fallout from his milk as soon as...

Tracking Radionuclide Fractionation in the First Atomic Explosion Using Stable Elements

DOE PAGES

Bonamici, Chloë E.; Hervig, Richard L.; Kinman, William S.

2017-08-25

Compositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. By using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclidesmore » generated during the explosion. Stable-element proxies show that radionuclides from the Trinity device were chemically, but not isotopically, fractionated by condensation. Moreover, stable-element proxies delineate chemical fractionation trends that can be used to connect present-day fallout composition to past fireball composition. Stable-element proxies therefore offer a novel approach for elucidating the phenomenology of the nuclear fireball as it relates to the formation of debris and the fixation of device materials within debris.« less

Reconstruction and analysis of 137Cs fallout deposition patterns in the Marshall Islands.

PubMed

Whitcomb, Robert C

2002-03-01

Estimates of 137Cs deposition caused by fallout originating from nuclear weapons testing in the Marshall Islands have been estimated for several locations in the Marshall Islands. These retrospective estimates are based primarily on historical exposure rate and gummed film measurements. The methods used to reconstruct these deposition estimates are similar to those used in the National Cancer Institute study for reconstructing 131I deposition from the Nevada Test Site. Reconstructed cumulative deposition estimates are validated against contemporary measurements of 137Cs concentration in soil with account taken for estimated global fallout contributions. These validations show that the overall geometric bias in predicted-to-observed (P:O) ratios is 1.0 (indicating excellent agreement). The 5th to 95th percentile range of this distribution is 0.35-2.95. The P:O ratios for estimates using historical gummed film measurements tend to slightly overpredict more than estimates using exposure rate measurements. The deposition estimate methods, supported by the agreement between estimates and measurements, suggest that these methods can be used with confidence for other weapons testing fallout radionuclides.

Tracking Radionuclide Fractionation in the First Atomic Explosion Using Stable Elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonamici, Chloë E.; Hervig, Richard L.; Kinman, William S.

Compositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. By using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclidesmore » generated during the explosion. Stable-element proxies show that radionuclides from the Trinity device were chemically, but not isotopically, fractionated by condensation. Moreover, stable-element proxies delineate chemical fractionation trends that can be used to connect present-day fallout composition to past fireball composition. Stable-element proxies therefore offer a novel approach for elucidating the phenomenology of the nuclear fireball as it relates to the formation of debris and the fixation of device materials within debris.« less

Tracking Radionuclide Fractionation in the First Atomic Explosion Using Stable Elements.

PubMed

Bonamici, Chloë E; Hervig, Richard L; Kinman, William S

2017-09-19

Compositional analysis of postdetonation fallout is a tool for forensic identification of nuclear devices. However, the relationship between device composition and fallout composition is difficult to interpret because of the complex combination of physical mixing, nuclear reactions, and chemical fractionations that occur in the chaotic nuclear fireball. Using a combination of in situ microanalytical techniques (electron microprobe analysis and secondary ion mass spectrometry), we show that some heavy stable elements (Rb, Sr, Zr, Ba, Cs, Ba, La, Ce, Nd, Sm, Dy, Lu, U, Th) in glassy fallout from the first nuclear test, Trinity, are reliable chemical proxies for radionuclides generated during the explosion. Stable-element proxies show that radionuclides from the Trinity device were chemically, but not isotopically, fractionated by condensation. Furthermore, stable-element proxies delineate chemical fractionation trends that can be used to connect present-day fallout composition to past fireball composition. Stable-element proxies therefore offer a novel approach for elucidating the phenomenology of the nuclear fireball as it relates to the formation of debris and the fixation of device materials within debris.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonamici, Chloë E.; Kinman, William S.; Fournelle, John H.

Reprocessed earth material is a glassy nuclear fallout debris from near-surface nuclear tests. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. Our study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclearmore » test (“trinitite”) and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. Furthermore, the volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionally with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.« less

Limits of fetal thyroid risk from radioiodine exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lloyd, R.D.; Tripp, D.A.; Kerber, R.A.

1996-04-01

An incident in which a young women became pregnant soon after being treated with 444 MBq {sup 131}I for Graves disease prompted us to search local records for the occurrence of thyroid abnormalities among people exposed in utero to fallout radioiodine. The data base from the Utah Fallout Study indicated that there had been 480 cohort subjects for whom dose to thyroid from fallout radioiodine had been calculated and who could have received any thyroid dose before birth (2473 subjects had been re-examined in 1985-86 of the 4818 examined in 1965-70). Of these 480 subjects in this category, 403 ofmore » them could be located in the 1980`s and were examined for abnormalities. Although nodules, thyroiditis, hypothyroidism and goiter were seen among the 375 persons with in utero thyroid doses from fallout radioiodine below 0.42 Gy, no thyroid abnormalities of any kind occurred in the 4 persons with in utero thyroid doses of 0.5 to 2.6 Gy. In addition, no neoplasia was found in any of the 403 subjects examined about 3 decades after in utero fallout exposure. These limited data do not indicate that the fetal thyroid is more sensitive than the postnatal thyroid by more than about a factor of about 4 when thyroid dose is considered and by not much more than unity when the comparison is based on dose equivalent (x-ray vs. radioiodine). 21 refs., 1 tab.« less

Sources of plutonium to the tropical Northwest Pacific Ocean (1943-1999) identified using a natural coral archive

NASA Astrophysics Data System (ADS)

Lindahl, Patric; Asami, Ryuji; Iryu, Yasufumi; Worsfold, Paul; Keith-Roach, Miranda; Choi, Min-Seok

2011-03-01

The Pu isotopes, 239Pu and 240Pu, were determined in annually-banded skeletons of an accurately dated (1943-1999) modern coral ( Porites lobata) from Guam Island to identify historical Pu sources to the tropical Northwest Pacific Ocean. Activity concentrations of 239+240Pu and 240Pu/ 239Pu atom ratios were determined in the dated coral bands using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). Close-in fallout from the former US Pacific Proving Grounds (PPG) in the Marshall Islands and global fallout were identified as the two main sources. The Guam site was dominated by PPG close-in fallout in the 1950s, with an average 240Pu/ 239Pu atom ratio of 0.315 ± 0.005. In addition, a higher 240Pu/ 239Pu atom ratio (0.456 ± 0.020) was observed that could be attributed to fallout from the "Ivy Mike" thermonuclear detonation in 1952. The atom ratio decreased in the 1960s and 1970s due to increase in the global fallout with a low 240Pu/ 239Pu atom ratio (˜0.18). Recent coral bands (1981-1999) are dominated by the transport of remobilised Pu, with high 240Pu/ 239Pu atom ratios, from the Marshall Islands to Guam Island along the North Equatorial Current (NEC). This remobilised Pu was estimated to comprise 69% of the total Pu in the recent coral bands, although its contribution was variable over time.

The distribution of meteoric Cl-36 in precipitation across Europe in spring 2007

NASA Astrophysics Data System (ADS)

Johnston, Vanessa E.; McDermott, Frank

2008-10-01

The cosmogenic isotope 36Cl is a valuable tool for understanding many Earth system processes, but an improved knowledge of its spatial distribution at the Earth's surface is critical for several applications. Meteoric 36Cl fallout reflects complex interactions between atmospheric production, transport, and deposition processes, and predictive models require experimental validation. This study investigates, for the first time in a systematic way, the spatial distribution of meteoric 36Cl on a continental scale within the European landmass using precipitation samples collected during spring 2007. 36Cl/Cl ratios increase with distance inland and the new data exhibit a strong exponential relationship with δ18O values of precipitation ( RS = - 0.75), yielding a useful predictive framework for future studies. Precipitation events in central European regions are characterised by high 36Cl/Cl ratios, with a maximum measured in Lyon, France of 746 (± 134) × 10 - 15 . The new data confirm models for the dependence of 36Cl fallout on latitude, with the highest mean springtime fallout (53.6 atoms m - 2 s - 1 ) occurring in the 40-50°N latitudinal band, with sharp decreases in fallout in high latitude regions and more gradual decreases towards the lower latitudes. The 36Cl bomb pulse, introduced by thermonuclear weapon testing, predominantly in the 1950's, has persisted in the environment for c. 50 years, but the new data indicate that 36Cl fallout has now essentially returned to natural, pre-bomb values.

Fallout volume and litter type affect 137Cs concentration difference in litter between forest and stream environments.

PubMed

Sakai, Masaru; Gomi, Takashi; Negishi, Junjiro N

2016-11-01

It is important to understand the changes in the 137 Cs concentration in litter through leaching when considering that 137 Cs is transferred from basal food resources to animals in forested streams. We found that the difference of 137 Cs activity concentration in litter between forest and stream was associated with both litter type and 137 Cs fallout volume around Fukushima, Japan. The 137 Cs activity concentrations in the litter of evergreen conifers tended to be greater than those in the litter of broad-leaved deciduous trees because of the absence of deciduous leaves during the fallout period in March 2011. Moreover, 137 Cs activity concentrations in forest litter were greater with respect to the 137 Cs fallout volume. The 137 Cs activity concentrations in stream litter were much lower than those in forest litter when those in forest litter were higher. The 137 Cs leaching patterns indicated that the differences in 137 Cs activity concentration between forest and stream litter could change with changes in both fallout volume and litter type. Because litter is an important basal food resource in the food webs of both forests and streams, the 137 Cs concentration gradient reflects to possible 137 Cs transfer from lower to higher trophic animals. Our findings will improve our understanding of the spatial heterogeneity and variability of 137 Cs concentrations in animals resident to the contaminated landscape. Copyright © 2016 Elsevier Ltd. All rights reserved.

An experiment on radioactive equilibrium and its modelling using the ‘radioactive dice’ approach

NASA Astrophysics Data System (ADS)

Santostasi, Davide; Malgieri, Massimiliano; Montagna, Paolo; Vitulo, Paolo

2017-07-01

In this article we describe an educational activity on radioactive equilibrium we performed with secondary school students (17-18 years old) in the context of a vocational guidance stage for talented students at the Department of Physics of the University of Pavia. Radioactive equilibrium is investigated experimentally by having students measure the activity of 214Bi from two different samples, obtained using different preparation procedures from an uraniferous rock. Students are guided in understanding the mathematical structure of radioactive equilibrium through a modelling activity in two parts. Before the lab measurements, a dice game, which extends the traditional ‘radioactive dice’ activity to the case of a chain of two decaying nuclides, is performed by students divided into small groups. At the end of the laboratory work, students design and run a simple spreadsheet simulation modelling the same basic radioactive chain with user defined decay constants. By setting the constants to realistic values corresponding to nuclides of the uranium decay chain, students can deepen their understanding of the meaning of the experimental data, and also explore the difference between cases of non-equilibrium, transient and secular equilibrium.

[Separation of the effects of transmutation and radiation after incorporation of radionuclides into DNA (author's transl)].

PubMed

Hamann, H J; Irskens, M

1975-01-01

Among the various methods for studying the relative effects of transmutation and radiation of incorporated nuclides, simulation of beta radiation by external gamma exposure is of practical importance. Self-irradiation and mutual irradiation of the labeled cells cannot be neglected in any case. Furthermore, additional hypothetical and experimental problems may arise from using either external beta radiation or different isotopes of an element. By means of external gamma irradiation on the other hand, this being equivalent to the internal beta radiation from a microdosimetrical point of view, the radiation effect of the nuclide alone can be observed without any modification of other experimental parameters. To determine such equivalent gamma radiation for labeled cell nuclei of Vicia faba roots, the authors applied the Monte Carlo Method to the beta spectra of 32-P, 3-H, 14-C and 131-J, to the energy-dependent LET and to different cell diameters. The existence of secondary particle equilibrium inside the nuclei during gamma exposure was assumed. For certain radionuclides and cell sizes it is possible to calculate gamma spectra which induce energy spectra in the nuclei similar to those caused by the beta particles originating in the nuclear DNA.

Resolving global versus local/regional Pu sources in the environment using sector ICP-MS

USGS Publications Warehouse

Ketterer, M.E.; Hafer, K.M.; Link, C.L.; Kolwaite, D.; Wilson, Jim; Mietelski, J.W.

2004-01-01

Sector inductively coupled plasma mass spectrometry is a versatile method for the determination of plutonium activities and isotopic compositions in samples containing this element at fallout levels. Typical detection limits for 239+240Pu are 0.1, 0.02 and 0.002 Bq kg -1Pu for samples sizes of 0.5 g, 3 g, and 50 g of soil, respectively. The application of sector ICP-MS-based Pu determinations is demonstrated in studies in sediment chronology, soil Pu inventory and depth distribution, and the provenance of global fallout versus local or regional Pu sources. A sediment core collected from Sloans Lake (Denver, Colorado, USA) exhibits very similar 137Cs and 239+240Pu activity profiles; 240Pu/239Pu atom ratios indicate possible small influences from the Nevada Test Site and/or the Rocky Flats Environmental Technology Site. An undisturbed soil profile from Lockett Meadow (Flagstaff, Arizona, USA) exhibits an exponential decrease in 239+240Pu activity versus depth; 240Pu/239Pu in the top 3 cm is slightly lower than the global fallout range of 0.180 ?? 0.014 due to possible regional influence of Nevada Test Site fallout. The 239??240Pu inventory at Lockett Meadow is 56 ?? 4 Bq m-2, consistent with Northern Hemisphere mid-latitude fallout. Archived NdF3 sources, prepared from Polish soils, demonstrate that substantial 239+240Pu from the 1986 Chernobyl disaster has been deposited in north eastern regions of Poland; compared to global fallout, Chernobyl Pu exhibits higher abundances of 240Pu and 241Pu. The ratios 240Pu/239pu and 241Pu/239Pu co-vary and range from 0.186-0.348 and 0.0029-0.0412, respectively, in forest soils (241Pu/239Pu = 0.2407??[240Pu/239Pu] - 0.0413; r2 = 0.9924). ?? The Royal Society of Chemistry 2004.

Neogene Fallout Tuffs from the Yellowstone Hotspot in the Columbia Plateau Region, Oregon, Washington and Idaho, USA

PubMed Central

Nash, Barbara P.; Perkins, Michael E.

2012-01-01

Sedimentary sequences in the Columbia Plateau region of the Pacific Northwest ranging in age from 16–4 Ma contain fallout tuffs whose origins lie in volcanic centers of the Yellowstone hotspot in northwestern Nevada, eastern Oregon and the Snake River Plain in Idaho. Silicic volcanism began in the region contemporaneously with early eruptions of the Columbia River Basalt Group (CRBG), and the abundance of widespread fallout tuffs provides the opportunity to establish a tephrostratigrahic framework for the region. Sedimentary basins with volcaniclastic deposits also contain diverse assemblages of fauna and flora that were preserved during the Mid-Miocene Climatic Optimum, including Sucker Creek, Mascall, Latah, Virgin Valley and Trout Creek. Correlation of ashfall units establish that the lower Bully Creek Formation in eastern Oregon is contemporaneous with the Virgin Valley Formation, the Sucker Creek Formation, Oregon and Idaho, Trout Creek Formation, Oregon, and the Latah Formation in the Clearwater Embayment in Washington and Idaho. In addition, it can be established that the Trout Creek flora are younger than the Mascall and Latah flora. A tentative correlation of a fallout tuff from the Clarkia fossil beds, Idaho, with a pumice bed in the Bully Creek Formation places the remarkably well preserved Clarkia flora assemblage between the Mascall and Trout Creek flora. Large-volume supereruptions that originated between 11.8 and 10.1 Ma from the Bruneau-Jarbidge and Twin Falls volcanic centers of the Yellowstone hotspot in the central Snake River Plain deposited voluminous fallout tuffs in the Ellensberg Formation which forms sedimentary interbeds in the CRBG. These occurrences extend the known distribution of these fallout tuffs 500 km to the northwest of their source in the Snake River Plain. Heretofore, the distal products of these large eruptions had only been recognized to the east of their sources in the High Plains of Nebraska and Kansas. PMID:23071494

Neogene fallout tuffs from the Yellowstone hotspot in the Columbia Plateau region, Oregon, Washington and Idaho, USA.

PubMed

Nash, Barbara P; Perkins, Michael E

2012-01-01

Sedimentary sequences in the Columbia Plateau region of the Pacific Northwest ranging in age from 16-4 Ma contain fallout tuffs whose origins lie in volcanic centers of the Yellowstone hotspot in northwestern Nevada, eastern Oregon and the Snake River Plain in Idaho. Silicic volcanism began in the region contemporaneously with early eruptions of the Columbia River Basalt Group (CRBG), and the abundance of widespread fallout tuffs provides the opportunity to establish a tephrostratigrahic framework for the region. Sedimentary basins with volcaniclastic deposits also contain diverse assemblages of fauna and flora that were preserved during the Mid-Miocene Climatic Optimum, including Sucker Creek, Mascall, Latah, Virgin Valley and Trout Creek. Correlation of ashfall units establish that the lower Bully Creek Formation in eastern Oregon is contemporaneous with the Virgin Valley Formation, the Sucker Creek Formation, Oregon and Idaho, Trout Creek Formation, Oregon, and the Latah Formation in the Clearwater Embayment in Washington and Idaho. In addition, it can be established that the Trout Creek flora are younger than the Mascall and Latah flora. A tentative correlation of a fallout tuff from the Clarkia fossil beds, Idaho, with a pumice bed in the Bully Creek Formation places the remarkably well preserved Clarkia flora assemblage between the Mascall and Trout Creek flora. Large-volume supereruptions that originated between 11.8 and 10.1 Ma from the Bruneau-Jarbidge and Twin Falls volcanic centers of the Yellowstone hotspot in the central Snake River Plain deposited voluminous fallout tuffs in the Ellensberg Formation which forms sedimentary interbeds in the CRBG. These occurrences extend the known distribution of these fallout tuffs 500 km to the northwest of their source in the Snake River Plain. Heretofore, the distal products of these large eruptions had only been recognized to the east of their sources in the High Plains of Nebraska and Kansas.

Methods of increasing the performance of radionuclide generators used in nuclear medicine: daughter nuclide build-up optimisation, elution-purification-concentration integration, and effective control of radionuclidic purity.

PubMed

Le, Van So; Do, Zoe Phuc-Hien; Le, Minh Khoi; Le, Vicki; Le, Natalie Nha-Truc

2014-06-10

Methods of increasing the performance of radionuclide generators used in nuclear medicine radiotherapy and SPECT/PET imaging were developed and detailed for 99Mo/99mTc and 68Ge/68Ga radionuclide generators as the cases. Optimisation methods of the daughter nuclide build-up versus stand-by time and/or specific activity using mean progress functions were developed for increasing the performance of radionuclide generators. As a result of this optimisation, the separation of the daughter nuclide from its parent one should be performed at a defined optimal time to avoid the deterioration in specific activity of the daughter nuclide and wasting stand-by time of the generator, while the daughter nuclide yield is maintained to a reasonably high extent. A new characteristic parameter of the formation-decay kinetics of parent/daughter nuclide system was found and effectively used in the practice of the generator production and utilisation. A method of "early elution schedule" was also developed for increasing the daughter nuclide production yield and specific radioactivity, thus saving the cost of the generator and improving the quality of the daughter radionuclide solution. These newly developed optimisation methods in combination with an integrated elution-purification-concentration system of radionuclide generators recently developed is the most suitable way to operate the generator effectively on the basis of economic use and improvement of purposely suitable quality and specific activity of the produced daughter radionuclides. All these features benefit the economic use of the generator, the improved quality of labelling/scan, and the lowered cost of nuclear medicine procedure. Besides, a new method of quality control protocol set-up for post-delivery test of radionuclidic purity has been developed based on the relationship between gamma ray spectrometric detection limit, required limit of impure radionuclide activity and its measurement certainty with respect to optimising decay/measurement time and product sample activity used for QC quality control. The optimisation ensures a certainty of measurement of the specific impure radionuclide and avoids wasting the useful amount of valuable purified/concentrated daughter nuclide product. This process is important for the spectrometric measurement of very low activity of impure radionuclide contamination in the radioisotope products of much higher activity used in medical imaging and targeted radiotherapy.

[Comparative analysis of the radionuclide composition in fallout after the Chernobyl and the Fukushima accidents].

PubMed

Kotenko, K V; Shinkarev, S M; Abramov, Iu V; Granovskaia, E O; Iatsenko, V N; Gavrilin, Iu I; Margulis, U Ia; Garetskaia, O S; Imanaka, T; Khoshi, M

2012-01-01

The nuclear accident occurred at Fukushima Dai-ichi Nuclear Power Plant (NPP) (March 11, 2011) similarly to the accident at the Chernobyl NPP (April 26, 1986) is related to the level 7 of the INES. It is of interest to make an analysis of the radionuclide composition of the fallout following the both accidents. The results of the spectrometric measurements were used in that comparative analysis. Two areas following the Chernobyl accident were considered: (1) the near zone of the fallout - the Belarusian part of the central spot extended up to 60 km around the Chernobyl NPS and (2) the far zone of the fallout--the "Gomel-Mogilev" spot centered 200 km to the north-northeast of the damaged reactor. In the case of Fukushima accident the near zone up to about 60 km considered. The comparative analysis has been done with respect to refractory radionuclides (95Zr, 95Nb, 141Ce, 144Ce), as well as to the intermediate and volatile radionuclides 103Ru, 106Ru, 131I, 134Cs, 137Cs, 140La, 140Ba and the results of such a comparison have been discussed. With respect to exposure to the public the most important radionuclides are 131I and 137Cs. For the both accidents the ratios of 131I/137Cs in the considered soil samples are in the similar ranges: (3-50) for the Chernobyl samples and (5-70) for the Fukushima samples. Similarly to the Chernobyl accident a clear tendency that the ratio of 131I/137Cs in the fallout decreases with the increase of the ground deposition density of 137Cs within the trace related to a radioactive cloud has been identified for the Fukushima accident. It looks like this is a universal tendency for the ratio of 131I/137Cs versus the 137Cs ground deposition density in the fallout along the trace of a radioactive cloud as a result of a heavy accident at the NPP with radionuclides releases into the environment. This tendency is important for an objective reconstruction of 131I fallout based on the results of 137Cs measurements of soil samples carried out at late dates after the Fukushima accident.

Tracking Radioactive Fallout from the Fukushima Dai-ichi Accident in Arctic Snow

NASA Astrophysics Data System (ADS)

Osterberg, E. C.; Thompson, J.; Landis, J.; Albert, M. R.; Campbell, S. W.; Hawley, R. L.; Virginia, R. A.

2011-12-01

The March 11, 2011 magnitude 9.0 Tohoku, Japan earthquake produced a tsunami that inundated the Fukushima Dai-ichi nuclear power plant and led to the accidental release of radioactive 131I, 132Te, 134Cs, and 137Cs to the atmosphere. The Japanese Nuclear Safety Commission estimates that 12,000 TBq of 137Cs were released to the atmosphere during the incident, which represents ~14% of the total estimated 137Cs emission from the Chernobyl disaster in April 1986. Measurements of airborne radiation collected at the Fukushima plant illustrate that >50% of the total emitted radiation was released on March 15 and 16 associated with explosions and fires at reactor units 1, 2, and 4, and 70% was emitted in the first 5 days of the event. The source of the radiation is thus well constrained in time and space, providing an opportunity to better understand long-range atmospheric transport processes from Asia to the Arctic, while also assessing the magnitude of the fallout in the Arctic. Here we describe the 137Cs and 134Cs fallout flux near Thule, Greenland (1700 m a.s.l.), at Summit (3200 m a.s.l.), Greenland, and within Denali National Park, Alaska (2400-3900 m a.s.l.) based on series of large-volume (5-15 l) snow pit samples collected in June and July, 2011. In addition to assessing the spatial variability of Fukushima fallout in the Arctic, the elevation range of samples allows for an analysis of any vertical heterogeneity in fallout transport and deposition. Major ion concentrations and stable water isotope ratios are used to confirm the seasonal timing of the Fukushima fallout horizon in the snowpack. Radiocesium was concentrated and isolated from the snow pit meltwater using the well-established ammonium phosphomolybdate (AMP) adsorption method, and 134Cs and 137Cs concentrations were measured using gamma spectrometry with a Canberra 3523 well-type intrinsic Ge-detector at the Dartmouth College Short-Lived Isotope Laboratory. NOAA HYPLIT atmospheric forward-trajectory model results are integrated with the radiocesium flux measurements and emission estimates to investigate long-range atmospheric transport paths and mechanisms. Furthermore, we evaluate the potential to use the Fukushima fallout horizon as an absolute time marker in future Arctic ice core studies.

²³⁹Pu and ²⁴⁰Pu inventories and ²⁴⁰Pu/²³⁹Pu atom ratios in the equatorial Pacific Ocean water column.

PubMed

Yamada, Masatoshi; Zheng, Jian

2012-07-15

The (239+240)Pu concentrations and (240)Pu/(239)Pu atom ratios were determined by alpha spectrometry and inductively coupled plasma mass spectrometry for seawater samples from two stations, one at the equator and the other in the equatorial South Pacific. To better understand the fate of Pu isotopes, this study dealt with the contribution of the close-in fallout Pu from the Pacific Proving Grounds (PPG) in water columns of the Pacific Ocean. The (239)Pu, (240)Pu and (239+240)Pu inventories over the depth interval 0-3000 m at the equator station were 10.4, 8.9 and 19.3 Bq m(-2), respectively. Further, no noticeable difference was observed in (239)Pu, (240)Pu and (239+240)Pu inventories over the depth interval 0-3000 m between the two stations. The total (239+240)Pu inventories were significantly higher than the expected cumulative deposition density of global fallout. Water column (239+240)Pu inventories measured in this study were lower than those reported for comparable stations in the Geochemical Ocean Sections Study, indicating that these inventories have been decreasing at average rates of 0.89 ± 0.07 and 0.16 ± 0.07 Bq m(-2)yr(-1) at the equator and equatorial South Pacific stations, respectively, from 1973 to 1990. The obtained (240)Pu/(239)Pu atom ratios were higher than the mean global fallout ratio of 0.18. These high atom ratios proved the existence of close-in tropospheric fallout Pu from the PPG in the Marshall Islands. The (239+240)Pu inventories originating from the close-in fallout in the entire water column were estimated to be 11.1 Bq m(-2) at the equator station and 7.1 Bq m(-2) at the equatorial South Pacific Ocean station, and the relative percentages of close-in fallout Pu were 40% at the former and 34% at the latter. A significant amount of close-in fallout Pu originating from the PPG has been transported to deep layers below the 1000 m depth in the equatorial Pacific Ocean. Copyright © 2012 Elsevier B.V. All rights reserved.

The basal fallout and surge deposits of the mafic ignimbrite-forming Villa Senni Eruption Unit, (Colli Albani volcano, Italy)

NASA Astrophysics Data System (ADS)

Vinkler, A.; Ort, M. H.; Giordano, G.

2009-12-01

The Villa Senni Eruption Unit (350ka) represents the youngest large caldera-forming eruption of the Colli Albani volcano near Rome (Italy). The Colli Albani magma is marked by very undersaturated chemistry (tephritic to K-foiditic) and low viscosity. The total volume of the Villa Senni Eruption Unit is estimated at > 50 km3 and 30 km3 DRE (Watkins et al., 2002). The unit includes a sequence of a basal fallout/surge deposit, two main ignimbrites emplaced during the same eruptive event, a series of breccia deposits positioned between the two ignimbrites, and a rarely preserved final fallout. The basal surge and fallout sequence may help answer questions regarding the beginning of a large mafic ignimbrite eruption. The entire surge and fallout deposit is 190 cm thick at the caldera wall, consisting of 19 individual, parallel to faintly cross-stratified layers. The deposit distally thins to 25 cm at 18 km east of the caldera and to 2.5 cm at 21 km NW of the caldera. The eruption started with fine ash surges showing cross-stratification at proximal locations and being vesicular distally. The deposit consists mainly of juvenile clasts, which are angular, poorly vesicular, and rich in leucite microlites (~80 µm). Clasts around 100-150 μm show signs of magma-water interaction: quench fracturing: conchoidal and step fractures, smooth surfaces, adhering clasts and melt film. These features are present in several thin alternating surge and fall sequences at the base of the deposit. The lithic clasts in these first deposits are concentrated in layers, indicating pulsatory behavior of the eruption. Upward, the deposit consists of thicker, coarse ash to lapilli fallout layers from more sustained columns. The juvenile clasts in these deposits are more irregular, with higher vesicularity (but less than 50%) and smaller leucite microlites (~60 μm). The uppermost part of the basal fallout/surge deposit shows features transitional to the first large ignimbrite: fallout deposits alternate with poorly sorted flow units, with an increase in free leucite crystals and lithic content, with more abundant deep lithic clasts and a further leucite microlite size decrease (~20 μm) , which could indicate an accelerating magma in the conduit. We think that external factors, such as magma-water interaction and consequent gas explosions, triggered the highly explosive Villa Senni Eruption. Low vesicularity of the early juvenile clasts suggests the magma was relatively low in volatiles at the outset and did not start as a gas-driven eruption. Later in the eruption, the high ascent rate and fast decompression of the magma sustained a large explosive eruption.

Short term soil erosion dynamics in alpine grasslands - Results from a Fallout Radionuclide repeated-sampling approach

NASA Astrophysics Data System (ADS)

Arata, Laura; Meusburger, Katrin; Zehringer, Markus; Ketterer, Michael E.; Mabit, Lionel; Alewell, Christine

2016-04-01

Improper land management and climate change has resulted in accelerated soil erosion rates in Alpine grasslands. To efficiently mitigate and control soil erosion and reduce its environmental impact in Alpine grasslands, reliable and validated methods for comprehensive data generation on its magnitude and spatial extent are mandatory. The use of conventional techniques (e.g. sediment traps, erosion pins or rainfall simulations) may be hindered by the extreme topographic and climatic conditions of the Alps. However, the application of the Fallout Radionuclides (FRNs) as soil tracers has already showed promising results in these specific agro-ecosystems. Once deposited on the ground, FRNs strongly bind to fine particles at the surface soil and move across the landscape primarily through physical processes. As such, they provide an effective track of soil and sediment redistribution. So far, applications of FRN in the Alps include 137Cs (half-life: 30.2 years) and 239+240Pu (239Pu [half-life = 24110 years] and 240Pu [half-life = 6561 years]). To investigate short term (4-5 years) erosion dynamics in the Swiss Alps, the authors applied a FRNs repeated sampling approach. Two study areas in the central Swiss Alps have been investigated: the Urseren Valley (Canton Uri), where significant land use changes occurred in the last centuries, and the Piora Valley (Canton Ticino), where land use change plays a minor role. Soil samples have been collected at potentially erosive sites along the valleys over a period of 4-5 years and measured for 137Cs and 239+240Pu activity. The inventory change between the sampling years indicates high erosion and deposition dynamics at both valleys. High spatial variability of 137Cs activities at all sites has been observed, reflecting the heterogeneous distribution of 137Cs fallout after the Chernobyl power plant accident in 1986. Finally, a new modelling technique to convert the inventory changes to quantitative estimates of soil erosion has been tested.

Mass Transport of Condensed Species in Aerodynamic Fallout Glass from a Near-Surface Nuclear Test

NASA Astrophysics Data System (ADS)

Weisz, David Gabriel

In a near-surface nuclear explosion, vaporized device materials are incorporated into molten soil and other carrier materials, forming glassy fallout upon quenching. Mechanisms by which device materials mix with carrier materials have been proposed, however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. A surface deposition layer was observed preserved at interfaces where two aerodynamic fallout glasses agglomerated and fused. Eleven such boundaries were studied using spatially resolved analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nano-scale secondary ion mass spectrometry (NanoSIMS), we identified higher concentrations of uranium from the device in 7 of the interface layers, as well as isotopic enrichment (>75% 235U) in 9 of the interface layers. Major element analysis of the interfaces revealed the deposition layer to be chemically enriched in Fe-, Ca- and Na-bearing species and depleted in Ti- and Al-bearing species. The concentration profiles of the enriched species at the interface are characteristic of diffusion. Three of the uranium concentration profiles were fit with a modified Gaussian function, representative of 1-D diffusion from a planar source, to determine time and temperature parameters of mass transport. By using a historical model of fireball temperature to simulate the cooling rate at the interface, the temperature of deposition was estimated to be 2200 K, with 1? uncertainties in excess of 140 K. The presence of Na-species in the layers at this estimated temperature of deposition is indicative of an oxygen rich fireball. The notable depletion of Al-species, a refractory oxide that is highly abundant in the soil, together with the enrichment of Ca-, Fe-, and 235U-species, suggests an anthropogenic source of the enriched species, together with a continuous chemical fractionation process as these species condensed.

Apparatus and method for quantitatively evaluating total fissile and total fertile nuclide content in samples

DOEpatents

Caldwell, John T.; Kunz, Walter E.; Cates, Michael R.; Franks, Larry A.

1985-01-01

Simultaneous photon and neutron interrogation of samples for the quantitative determination of total fissile nuclide and total fertile nuclide material present is made possible by the use of an electron accelerator. Prompt and delayed neutrons produced from resulting induced fissions are counted using a single detection system and allow the resolution of the contributions from each interrogating flux leading in turn to the quantitative determination sought. Detection limits for .sup.239 Pu are estimated to be about 3 mg using prompt fission neutrons and about 6 mg using delayed neutrons.

Apparatus and method for quantitatively evaluating total fissile and total fertile nuclide content in samples. [Patent application

DOEpatents

Caldwell, J.T.; Kunz, W.E.; Cates, M.R.; Franks, L.A.

1982-07-07

Simultaneous photon and neutron interrogation of samples for the quantitative determination of total fissile nuclide and total fertile nuclide material present is made possible by the use of an electron accelerator. Prompt and delayed neutrons produced from resulting induced fission are counted using a single detection system and allow the resolution of the contributions from each interrogating flux leading in turn to the quantitative determination sought. Detection limits for /sup 239/Pu are estimated to be about 3 mg using prompt fission neutrons and about 6 mg using delayed neutrons.

Detailed deposition density maps constructed by large-scale soil sampling for gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accident.

PubMed

Saito, Kimiaki; Tanihata, Isao; Fujiwara, Mamoru; Saito, Takashi; Shimoura, Susumu; Otsuka, Takaharu; Onda, Yuichi; Hoshi, Masaharu; Ikeuchi, Yoshihiro; Takahashi, Fumiaki; Kinouchi, Nobuyuki; Saegusa, Jun; Seki, Akiyuki; Takemiya, Hiroshi; Shibata, Tokushi

2015-01-01

Soil deposition density maps of gamma-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant (NPP) accident were constructed on the basis of results from large-scale soil sampling. In total 10,915 soil samples were collected at 2168 locations. Gamma rays emitted from the samples were measured by Ge detectors and analyzed using a reliable unified method. The determined radioactivity was corrected to that of June 14, 2011 by considering the intrinsic decay constant of each nuclide. Finally the deposition maps were created for (134)Cs, (137)Cs, (131)I, (129m)Te and (110m)Ag. The radioactivity ratio of (134)Cs-(137)Cs was almost constant at 0.91 regardless of the locations of soil sampling. The radioactivity ratios of (131)I and (129m)Te-(137)Cs were relatively high in the regions south of the Fukushima NPP site. Effective doses for 50 y after the accident were evaluated for external and inhalation exposures due to the observed radioactive nuclides. The radiation doses from radioactive cesium were found to be much higher than those from the other radioactive nuclides. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Fallout Radioactivity and Epiphytes.

Treesearch

H. T. Odum; George Ann Briscoe; C. B. Briscoe

1970-01-01

After relatively high levels of fallout retention were dicovered in the epiphytic mossy forest of the Luquillo Mountains durin 1962, a survey of the distribution of radioactivity in the rain forest system was made with beta counting of 1500 samples supplemented with gamma spectra. High levels, up to 4138 counts per minute per gram, were found mainly in or on green...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klement, A.W. Jr. ed.

Thirty papers are presented reviewing AEC research projects related to fall-out from weapons tests. Reviews of specific related programs by representatives from Canada and the UK are also included. The scope of the conference includes characteristics of fall-out, atmospheric factors affecting deposition, distribution in the environment, and distribution in the food chain and man. Separate abstracts have been prepared for each paper. (C.H.)

Nuclear Warfare Water Contamination.

DTIC Science & Technology

1982-05-01

obscured the important relationship between radionuclide ground concentrations and fallout dose rate contours by focusing too much attention on the...19 ) Radiological water contamination by nonpoint sources has received little, if any, attention in the current literature on the environmental... attention . Nevertheless, the environmental contamination of water supplies by fallout has been noted as a source of background radiation (20 ) and a possible

The Radioactive Contamination of Food Following Nuclear Attack

PubMed Central

Massey, E. E.

1967-01-01

The relative radiation hazards from early and delayed fallout following a nuclear attack have been reviewed. It is indicated that the hazard to life from whole-body gamma irradiation from early fallout far outweighs the hazard from radioactive contamination of food. Nevertheless, because of the possible effects of iodine-131, the consumption by infants of fresh milk from animals which have ingested contaminated fodder should be avoided if possible during the first few weeks after attack. During the same period, water from covered supplies should be used in preference to that from open reservoirs. It is more important, however, to alleviate hunger and thirst in both man and animal than to prevent the temporary ingestion of food which may be contaminated by fallout. PMID:6071130

MEASUREMENT OF THE ARTIFICIAL RADIOACTIVITY OF THE AIR AND OF FALL-OUT (in Italian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amadesi, P.; Cervellati, A.; Melandri, C.

1959-01-01

The results of the measurement of the artificial radioactivity of the air and of fall-out made in Italy from June 1958 to February 1959 are reported. The measurement stations were located at Bologna, Milan, Genoa, Trieste, Naples, Resina, and Bari. The techniques for collecting the samples and measuring their activity are described. Histograms of the activity obtained at the various stations are given. The meteorological factors affecting the activity and the correlation with nuclear explosions are discussed. The methods used to separate Ba/sup 137/, Sr/sup 90/, and Sr/sup 89/ in the fall-out samples are given. The gamma spectra obtained aremore » discussed. (J.S.R.)« less

Fallout traces of the Fukushima NPP accident in southern West Siberia (Novosibirsk, Russia).

PubMed

Melgunov, M S; Pokhilenko, N P; Strakhovenko, V D; Sukhorukov, F V; Chuguevskii, A V

2012-05-01

The fallout of artificially produced radioactive isotopes has been recorded at a site in southern West Siberia (54°50'43.6″ N, 083°06'22.4″ E, Novosibirsk, Russia). The highest activities of (131)I, (134)Cs, and (136)Cs were found in fresh snow precipitated on 02 April 2011, at 0.83, 0.092, and 0.002 Bq L(-1) of meltwater, respectively. The (131)I/(134)Cs ratio decreased from 9.0 on 02 April to 1.2 on 27 April, which is consistent with the radioactive decay of (131)I. This fallout can only have originated from the accidental emission of Fukushima Nuclear Power Plant, Japan, in March 2011.

Simulation of Martian dust accumulation on surfaces

NASA Technical Reports Server (NTRS)

Perez-Davis, Marla E.; Gaier, James R.; Kress, Robert; Grimalda, Justus

1990-01-01

Future NASA space missions include the possibility of manned landings and exploration of Mars. Environmental and operational constraints unique to Mars must be considered when selecting and designing the power system to be used on the Mars surface. A technique is described which was developed to simulate the deposition of dust on surfaces. Three kinds of dust materials were studied: aluminum oxide, basalt, and iron oxide. The apparatus was designed using the Stokes and Stokes-Cunningham law for particle fallout, with additional consideration given to particle size and shape. Characterization of the resulting dust films on silicon dioxide, polytetrafluoroethylene, indium tin oxide, diamondlike carbon, and other surfaces are discussed based on optical transmittance measurements. The results of these experiments will guide future studies which will consider processes to remove the dust from surfaces under Martian environmental conditions.

Production and Testing of the VITAMIN-B7 Fine-Group and BUGLE-B7 Broad-Group Coupled Neutron/Gamma Cross-Section Libraries Derived from ENDF/B-VII.0 Nuclear Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Risner, J. M.; Wiarda, D.; Dunn, M. E.

2011-09-30

New coupled neutron-gamma cross-section libraries have been developed for use in light water reactor (LWR) shielding applications, including pressure vessel dosimetry calculations. The libraries, which were generated using Evaluated Nuclear Data File/B Version VII Release 0 (ENDF/B-VII.0), use the same fine-group and broad-group energy structures as the VITAMIN-B6 and BUGLE-96 libraries. The processing methodology used to generate both libraries is based on the methods used to develop VITAMIN-B6 and BUGLE-96 and is consistent with ANSI/ANS 6.1.2. The ENDF data were first processed into the fine-group pseudo-problem-independent VITAMIN-B7 library and then collapsed into the broad-group BUGLE-B7 library. The VITAMIN-B7 library containsmore » data for 391 nuclides. This represents a significant increase compared to the VITAMIN-B6 library, which contained data for 120 nuclides. The BUGLE-B7 library contains data for the same nuclides as BUGLE-96, and maintains the same numeric IDs for those nuclides. The broad-group data includes nuclides which are infinitely dilute and group collapsed using a concrete weighting spectrum, as well as nuclides which are self-shielded and group collapsed using weighting spectra representative of important regions of LWRs. The verification and validation of the new libraries includes a set of critical benchmark experiments, a set of regression tests that are used to evaluate multigroup crosssection libraries in the SCALE code system, and three pressure vessel dosimetry benchmarks. Results of these tests confirm that the new libraries are appropriate for use in LWR shielding analyses and meet the requirements of Regulatory Guide 1.190.« less

Behavior of cesium in municipal solid waste incineration.

PubMed

Oshita, Kazuyuki; Aoki, Hiroshi; Fukutani, Satoshi; Shiota, Kenji; Fujimori, Takashi; Takaoka, Masaki

2015-05-01

As a result of the Fukushima Daiichi Nuclear Power Plant accident on March 11, 2011 in Japan radioactive nuclides, primarily (134)Cs and (137)Cs were released, contaminating municipal solid waste and sewage sludge in the area. Although stabilizing the waste and reducing its volume is an important issue differing from Chernobyl nuclear power plant accident, secondary emission of radioactive nuclides as a result of any intermediate remediation process is of concern. Unfortunately, there is little research on the behavior of radioactive nuclides during waste treatment. This study focuses on waste incineration in an effort to clarify the behavior of radioactive nuclides, specifically, refuse-derived fuel (RDF) with added (133)Cs (stable nuclide) or (134)Cs (radioactive nuclide) was incinerated in laboratory- and pilot-scale experiments. Next, thermogravimetric (TG) and differential thermal analysis (DTA) of stable Cs compounds, as well as an X-ray absorption fine structure (XAFS) analysis of Cs concentrated in the ashes were performed to validate the behavior and chemical forms of Cs during the combustion. Our results showed that at higher temperatures and at larger equivalence ratios, (133)Cs was distributed to the bottom ash at lower concentration, and the influence of the equivalence ratio was more significant at lower temperatures. (134)Cs behaved in a similar fashion as (133)Cs. We found through TG-DTA and XAFS analysis that a portion of Cs in RDF vaporizes and is transferred to fly ash where it exists as CsCl in the MSW incinerator. We conclude that Cs-contaminated municipal solid wastes could be incinerated at high temperatures resulting in a small amount of fly ash with a high concentration of radioactive Cs, and a bottom ash with low concentrations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Principles of Product Quality Control of German Radioactive Waste Forms from the Reprocessing of Spent Fuel: Vitrification, Compaction and Numerical Simulation - 12529

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tietze-Jaensch, Holger; Schneider, Stephan; Aksyutina, Yuliya

2012-07-01

The German product quality control is inter alia responsible for control of two radioactive waste forms of heat generating waste: a) homogeneous vitrified HLW and b) heterogeneous compacted hulls, end-pieces and technological metallic waste. In either case, significantly different metrology is employed at the site of the conditioning plant for the obligatory nuclide inventory declaration. To facilitate an independent evaluation and checking of the accompanying documentation numerical simulations are carried out. The physical and chemical properties of radioactive waste residues are used to assess the data consistency and uncertainty margins, as well as to predict the long-term behavior of themore » radioactive waste. This is relevant for repository acceptance and safety considerations. Our new numerical approach follows a bottom-up simulation starting from the burn-up behavior of the fuel elements in the reactor core. The output of these burn-up calculations is then coupled with a program that simulates the material separation in the subsequent dissolution and extraction processes normalized to the mass balance. Follow-up simulations of the separated reprocessing lines of a) the vitrification of highly-active liquid and b) the compaction of residual intermediate-active metallic hulls remaining after fuel pellets dissolution, end-pieces and technological waste, allows calculating expectation values for the various repository relevant properties of either waste stream. The principles of the German product quality control of radioactive waste residues from the spent fuel reprocessing have been introduced and explained. Namely, heat generating homogeneous vitrified HLW and heterogeneous compacted metallic MLW have been discussed. The advantages of a complementary numerical property simulation have been made clear and examples of benefits are presented. We have compiled a new program suite to calculate the physical and radio-chemical properties of common nuclear waste residues. The immediate benefit is the independent assessment of radio-active inventory declarations and much facilitated product quality control of waste residues that need to be returned to Germany and submitted to a German HLW-repository requirements. Wherever possible, internationally accepted standard programs are used and embedded. The innovative coupling of burn-up calculations (SCALE) with neutron and gamma transport codes (MCPN-X) allows an application in the world of virtual waste properties. If-then-else scenarios of hypothetical waste material compositions and distributions provide valuable information of long term nuclide property propagation under repository conditions over a very long time span. Benchmarking the program with real residue data demonstrates the power and remarkable accuracy of this numerical approach, boosting the reliability of the confidence aforementioned numerous applications, namely the proof tool set for on-the-spot production quality checking and data evaluation and independent verification. Moreover, using the numerical bottom-up approach helps to avoid the accumulation of fake activities that may gradually build up in a repository from the so-called conservative or penalizing nuclide inventory declarations. The radioactive waste properties and the hydrolytic and chemical stability can be predicted. The interaction with invasive chemicals can be assessed and propagation scenarios can be developed from reliable and sound data and HLW properties. Hence, the appropriate design of a future HLW repository can be based upon predictable and quality assured waste characteristics. (authors)« less

Analysis of fission and activation radionuclides produced by a uranium-fueled nuclear detonation and identification of the top dose-producing radionuclides.

PubMed

Kraus, Terry; Foster, Kevin

2014-08-01

The radiological assessment of the nuclear fallout (i.e., fission and neutron-activation radionuclides) from a nuclear detonation is complicated by the large number of fallout radionuclides. This paper provides the initial isotopic source term inventory of the fallout from a uranium-fueled nuclear detonation and identifies the significant and insignificant radiological dose producing radionuclides over 11 dose integration time periods (time phases) of interest. A primary goal of this work is to produce a set of consistent, time phase-dependent lists of the top dose-producing radionuclides that can be used to prepare radiological assessment calculations and data products (e.g., maps of areas that exceed protective action guidelines) in support of public and worker protection decisions. The ranked lists of top dose-producing radionuclides enable assessors to perform atmospheric dispersion modeling and radiological dose assessment modeling more quickly by using relatively short lists of radionuclides without significantly compromising the accuracy of the modeling and the dose projections. This paper also provides a superset-list of the top dose-producing fallout radionuclides from a uranium-fueled nuclear detonation that can be used to perform radiological assessments over any desired time phase. Furthermore, this paper provides information that may be useful to monitoring and sampling and laboratory analysis personnel to help understand which radionuclides are of primary concern. Finally, this paper may be useful to public protection decision makers because it shows the importance of quickly initiating public protection actions to minimize the radiological dose from fallout.

(236)U and (239,)(240)Pu ratios from soils around an Australian nuclear weapons test site.

PubMed

Tims, S G; Froehlich, M B; Fifield, L K; Wallner, A; De Cesare, M

2016-01-01

The isotopes (236)U, (239)Pu and (240)Pu are present in surface soils as a result of global fallout from nuclear weapons tests carried out in the 1950's and 1960's. These isotopes potentially constitute artificial tracers of recent soil erosion and sediment movement. Only Accelerator Mass Spectrometry has the requisite sensitivity to measure all three isotopes at these environmental levels. Coupled with its relatively high throughput capabilities, this makes it feasible to conduct studies of erosion across the geographical extent of the Australian continent. In the Australian context, however, global fallout is not the only source of these isotopes. As part of its weapons development program the United Kingdom carried out a series of atmospheric and surface nuclear weapons tests at Maralinga, South Australia in 1956 and 1957. The tests have made a significant contribution to the Pu isotopic abundances present in the region around Maralinga and out to distances ∼1000 km, and impact on the assessment techniques used in the soil and sediment tracer studies. Quantification of the relative fallout contribution derived from detonations at Maralinga is complicated owing to significant contamination around the test site from numerous nuclear weapons safety trials that were also carried out around the site. We show that (236)U can provide new information on the component of the fallout that is derived from the local nuclear weapons tests, and highlight the potential of (236)U as a new fallout tracer. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

[The biological effects of a nuclear explosion. Introduction of a new system on a colorimetric scale (black, grey, red, orange, yellow and white zone) to estimate the effects of fall-out on civilian populations].

PubMed

Nacci, G

2002-08-01

Following September 11 the eventuality of terrorist attacks using bags containing nuclear devices is considered possible in western cities like New York, London, Paris, Rome, Berlin, Moscow etc. However, with a modern Civil Defence programme the effects of a catastrophe of this nature can be partially limited, at least as far as Fall-out is concerned. The present paper explains the medical reasons for building anti-fall-out shelters for the larger part of western populations: from the USA to Russia. The paper also sets out a new method for classifying levels of radioactive Fall-out based on a scale of colours (black, grey, red, orange, yellow and white) whatever kind of radioactivity is involved (total gamma levels, Cesium 137 levels, Strontium 90 levels). The arrival times for fall-out in each area of the scale are fixed, whatever the energy of the explosion and the speed of the wind might be. The radioactive decay in each area of the scale, from the time of arrival of the fall-out is described with precision. Also described are the acute radiation syndrome, tumours, miscarriages and genetic diseases. A nomogram is attached for civil defence purposes showing the leeward extension of these areas, easily measurable in just a few minutes, if four parameters are known: ground zero (locality) of the explosion, the energy of the explosion, the direction of the wind and the speed of the wind.

Development and Validation of a New Fallout Transport Method Using Variable Spectral Winds

NASA Astrophysics Data System (ADS)

Hopkins, Arthur Thomas

A new method has been developed to incorporate variable winds into fallout transport calculations. The method uses spectral coefficients derived by the National Meteorological Center. Wind vector components are computed with the coefficients along the trajectories of falling particles. Spectral winds are used in the two-step method to compute dose rate on the ground, downwind of a nuclear cloud. First, the hotline is located by computing trajectories of particles from an initial, stabilized cloud, through spectral winds, to the ground. The connection of particle landing points is the hotline. Second, dose rate on and around the hotline is computed by analytically smearing the falling cloud's activity along the ground. The feasibility of using specgtral winds for fallout particle transport was validated by computing Mount St. Helens ashfall locations and comparing calculations to fallout data. In addition, an ashfall equation was derived for computing volcanic ash mass/area on the ground. Ashfall data and the ashfall equation were used to back-calculate an aggregated particle size distribution for the Mount St. Helens eruption cloud. Further validation was performed by comparing computed and actual trajectories of a high explosive dust cloud (DIRECT COURSE). Using an error propagation formula, it was determined that uncertainties in spectral wind components produce less than four percent of the total dose rate variance. In summary, this research demonstrated the feasibility of using spectral coefficients for fallout transport calculations, developed a two-step smearing model to treat variable winds, and showed that uncertainties in spectral winds do not contribute significantly to the error in computed dose rate.

Mid-Pleistocene cosmogenic minimum-age limits for pre-Wisconsinan glacial surfaces in southwestern Minnesota and southern Baffin Island: A multiple nuclide approach

USGS Publications Warehouse

Bierman, P.R.; Marsella, K.A.; Patterson, Chris; Davis, P.T.; Caffee, M.

1999-01-01

Paired 10Be and 26Al analyses (n = 14) indicate that pre-Wisconsinan, glaciated bedrock surfaces near the northern (Baffin Island) and southern (Minnesota) paleo-margins of the Laurentide Ice Sheet have long and complex histories of cosmic-ray exposure, including significant periods of partial or complete shielding from cosmic rays. Using the ratio, 26Al/10Be, we calculate that striated outcrops of Sioux Quartzite in southwestern Minnesota (southern margin) were last overrun by ice at least 500,000 years ago. Weathered bedrock tors on the once-glaciated uplands of Baffin Island (northern margin) are eroding no faster than 1.1 m Myr-1, the equivalent of at least 450,000 years of surface and near-surface exposure. Our data demonstrate that exposure ages and erosion rates calculated from single nuclides can underestimate surface stability dramatically because any intermittent burial, and the resultant lowering of nuclide production rates and nuclide abundances, will remain undetected.

VRF ("Visual RobFit") — nuclear spectral analysis with non-linear full-spectrum nuclide shape fitting

NASA Astrophysics Data System (ADS)

Lasche, George; Coldwell, Robert; Metzger, Robert

2017-09-01

A new application (known as "VRF", or "Visual RobFit") for analysis of high-resolution gamma-ray spectra has been developed using non-linear fitting techniques to fit full-spectrum nuclide shapes. In contrast to conventional methods based on the results of an initial peak-search, the VRF analysis method forms, at each of many automated iterations, a spectrum-wide shape for each nuclide and, also at each iteration, it adjusts the activities of each nuclide, as well as user-enabled parameters of energy calibration, attenuation by up to three intervening or self-absorbing materials, peak width as a function of energy, full-energy peak efficiency, and coincidence summing until no better fit to the data can be obtained. This approach, which employs a new and significantly advanced underlying fitting engine especially adapted to nuclear spectra, allows identification of minor peaks that are masked by larger, overlapping peaks that would not otherwise be possible. The application and method are briefly described and two examples are presented.

Approach for validating actinide and fission product compositions for burnup credit criticality safety analyses

DOE PAGES

Radulescu, Georgeta; Gauld, Ian C.; Ilas, Germina; ...

2014-11-01

This paper describes a depletion code validation approach for criticality safety analysis using burnup credit for actinide and fission product nuclides in spent nuclear fuel (SNF) compositions. The technical basis for determining the uncertainties in the calculated nuclide concentrations is comparison of calculations to available measurements obtained from destructive radiochemical assay of SNF samples. Probability distributions developed for the uncertainties in the calculated nuclide concentrations were applied to the SNF compositions of a criticality safety analysis model by the use of a Monte Carlo uncertainty sampling method to determine bias and bias uncertainty in effective neutron multiplication factor. Application ofmore » the Monte Carlo uncertainty sampling approach is demonstrated for representative criticality safety analysis models of pressurized water reactor spent fuel pool storage racks and transportation packages using burnup-dependent nuclide concentrations calculated with SCALE 6.1 and the ENDF/B-VII nuclear data. Furthermore, the validation approach and results support a recent revision of the U.S. Nuclear Regulatory Commission Interim Staff Guidance 8.« less

FIIDOS--A Computer Code for the Computation of Fallout Inhalation and Ingestion Dose to Organs Computer User’s Guide (Revision 4)

DTIC Science & Technology

2007-05-01

35 5 Actinide product radionuclides... actinides , and fission products in fallout. Doses from low-linear energy transfer (LET) radiation (beta particles and gamma rays) are reported separately...assumptions about the critical parameters used in calculating internal doses – resuspension factor, breathing rate, fractionation, and scenario elements – to

The nature of rockfall as the basis for a new fallout area design criteria for 0.25:1 slopes.

DOT National Transportation Integrated Search

1994-09-01

The data gathered from rolling nearly 2800 rocks off several 0.25H:1V slopes into three differently shaped ditches (flat, 6H:1V and 4H:1V) was used to develop 12 design charts for rock fallout areas. The data were analyzed using simple statistical an...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lloyd, R.D.; Gren, D.C.; Simon, S.L.

External gamma-ray exposures from fallout originating at the Nevada Test Site (NTS) have been assigned to 6,507 individual subjects (1,177 leukemia cases and 5,330 control subjects) who died as Utah residents between 1952 and 1981. Leukemia cases were identified, confirmed, and classified by cell type from the Utah Cancer Registry, Utah State vital records, and medical records. Residential histories were obtained from the Deceased Membership File (DMF) of the Church of Jesus Christ of Latter-day Saints (LDS), supplemented by information from the LDS Church Census Records that were taken in 1950, 1955, and 1960-62. Control subjects were selected randomly withinmore » age strata from the DMF and were frequency-matched to the cases by age at death and for sex. Individual radiation exposures were assigned as a function of residence location and time interval for each residence during the fallout period (1951-1958) using geographic exposure data taken from the literature. Temporal distribution of exposure for subjects who resided in more than one locality or who were born or died during the fallout period was determined from data of other investigators. Calculated gamma-ray exposures for each place of residence were summed for each subject to yield the exposure to fallout from the NTS.« less

Radioecological indexes of fallout measurements from the Fukushima nuclear accident

NASA Astrophysics Data System (ADS)

Manolopoulou, Metaxia; Stoulos, Stylianos; Ioannidou, Alexandra; Vagena, Eleni

2014-05-01

Fallout from the Fukushima nuclear accident has been monitored for about 1 month in Thessaloniki, Northern Greece. Three different radionuclides, one short-lived, one relatively long-lived and one long- lived fission product were identified in air, grass and milk samples. The 131I, 137Cs and 134Cs activity concentrations in air reached 497, 145 and 126 μBqm-3, respectively on 4 April, 2011. These radionuclides are of particular concern regarding their transfer from the environment to population through the ingestion pathways for the assessment of the Fukushima accident consequences. Radioecological indexes (eco-indexes) of fallout measurements in the air-grass-cow-milk-man pathway for 131I were determined, as they are related to radiological impact of the Fukushima derived radionuclides on the public and environment.

Long-Term Consequences of Radioactive Fallout From Conflicts Involving Nuclear Explosions

NASA Astrophysics Data System (ADS)

Simon, S. L.; Bouville, A.

2006-12-01

This presentation will summarize past exposures of the public to radioactive fallout from nuclear testing and extrapolate to the possible fallout-related consequences from detonation of multiple warheads that might accompany international conflicts. Long-term consequences could be of three distinct types: (1) the abandonment of living areas that might be heavily contaminated; (2) the necessity to curtail use of particular agricultural products and foods, and (3) life-shortening due to increased rates of cancer and possibly some non-cancer diseases among the exposed populations. While the actual health and economic impact on the surviving public after such conflicts could vary tremendously depending on the number and sizes of explosions (fission yields), height of detonations, and the public's proximity to explosion sites, it is clear that multiple detonations would disperse radioactive products over large geographic areas. Our understanding of radioactive fallout is based on studies carried out for more than five decades on weapons testing fallout that originated from sites worldwide including Nevada, the Soviet Union, four locations in the Pacific, and elsewhere. Those studies have led to an understanding of the composition of radioactive fallout, of its radioactive qualities, and of its capacity to contaminate ground and agricultural products, as well as dwellings and workplaces located from a few km to tens of thousands of km from the explosion site. Though the most severe individual health consequences from exposure to fallout would most likely develop relatively close to the detonation sites (within a few hundred km), wide geographic distribution of fallout, well beyond the borders of the nations involved in the conflict, would affect much larger populations and would likely cause elevated cancer rates and cancer-related deaths among them for many decades following. While acute radiation symptoms (and even death) can result from very high short-term exposures (on the order of a few thousand times the annual dose from natural background radiation), the increase in the long-term rate of cancer development as a result of lower, chronic exposures due to the contamination of the habitat and of the dietary foodstuffs, will pose very difficult scientific, economic, political, and societal problems. Most areas close to sites of detonation (i.e., within about 1000 km) would be primarily impacted by radionuclides with shorter half-lives (i.e., less than 2 months), e.g., Zirconium-95, Niobium-95, Iodine-131, Iodine-132, Iodine-133, Barium-140, Lanthanum-140, and Strontium-89. Conversely, most areas at further distances would be primarily impacted by radionuclides with longer half-lives, e.g., Strontium-90 and Cesium-137 (each with half-lives of 30 years). Contaminating radionuclides with very long half-lives, e.g., Plutonium-239, which has a half-life of 24,000 years, will almost never limit habitation despite widespread fear of them.

Evaluation and Parameter Analysis of Burn up Calculations for the Assessment of Radioactive Waste - 13187

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fast, Ivan; Aksyutina, Yuliya; Tietze-Jaensch, Holger

2013-07-01

Burn up calculations facilitate a determination of the composition and nuclear inventory of spent nuclear fuel, if operational history is known. In case this information is not available, the total nuclear inventory can be determined by means of destructive or, even on industrial scale, nondestructive measurement methods. For non-destructive measurements however only a few easy-to-measure, so-called key nuclides, are determined due to their characteristic gamma lines or neutron emission. From these measured activities the fuel burn up and cooling time are derived to facilitate the numerical inventory determination of spent fuel elements. Most regulatory bodies require an independent assessment ofmore » nuclear waste properties and their documentation. Prominent part of this assessment is a consistency check of inventory declaration. The waste packages often contain wastes from different types of spent fuels of different history and information about the secondary reactor parameters may not be available. In this case the so-called characteristic fuel burn up and cooling time are determined. These values are obtained from a correlations involving key-nuclides with a certain bandwidth, thus with upper and lower limits. The bandwidth is strongly dependent on secondary reactor parameter such as initial enrichment, temperature and density of the fuel and moderator, hence the reactor type, fuel element geometry and plant operation history. The purpose of our investigation is to look into the scaling and correlation limitations, to define and verify the range of validity and to scrutinize the dependencies and propagation of uncertainties that affect the waste inventory declarations and their independent verification. This is accomplished by numerical assessment and simulation of waste production using well accepted codes SCALE 6.0 and 6.1 to simulate the cooling time and burn up of a spent fuel element. The simulations are benchmarked against spent fuel from the real reactor Obrigheim in Germany for which sufficiently precise experimental reference data are available. (authors)« less

Measurement of beta-plus emitters by gamma-ray spectrometry.

PubMed

Lépy, Marie-Christine; Cassette, Philippe; Ferreux, Laurent

2010-01-01

The activity measurement of beta-plus emitters by gamma-ray spectrometry is studied. Experimental measurements are performed with (22)Na, (65)Zn and (64)Cu with sources included in a lead container. For these nuclides, the activity can be derived both from one photon emission peak and from the 511 keV annihilation peak, including annihilation in-flight correction and geometry correction computed by Monte Carlo simulation. The activity values obtained using the two types of peaks show satisfying agreement. The extension of the method to volume sources is discussed. Copyright 2009 Elsevier Ltd. All rights reserved.

Status of the PHOENIX electron cyclotron resonance charge breeder at ISOLDE, CERN.

PubMed

Barton, Charles; Cederkall, Joakim; Delahaye, Pierre; Kester, Oliver; Lamy, Thierry; Marie-Jeanne, Mélanie

2008-02-01

We report here on the last progresses made with the PHOENIX electron cyclotron resonance charge breeder test bench at ISOLDE. Recently, an experiment was performed to test the trapping of (61)Fe daughter nuclides from the decay of (61)Mn nuclides. Preliminary results are given.

VULNERABILITY OF HEADWATER CATCHMENT RESOURCES TO INCIDENCES OF 210PB EXCESS AND 137CS RADIONUCLIDE FALLOUT

EPA Science Inventory

Recent identification of elevated excess ²¹⁰Pb (≤302.6 mBq L^-1) and ¹³⁷Cs (≤ 111.3 mBq L^-1) activity in drinking water wells up to 20 m depth indicates some transport of airborne radionuclide fallout beyond soils in the Shaker Village c...

USSR and Eastern Europe Scientific Abstracts Geophysics, Astronomy and Space No. 404

DTIC Science & Technology

1977-09-01

atmospheric circulation. A reliable linear correlation was established between the monthly fallout activity of 10^Ru + -^Rh and monthly precipitation and...therefore the washing out of this radionuclide from tropospheric air by precipitation is more important for its fallout. [153] ANALYTICAL...development of some methods for predicting definite weather phenomena (such as precipitation ), taking into account the evolution of the

Description of and link to the I-131 dose/risk calculator

Cancer.gov

This calculator estimates radiation dose received by the thyroid from radionuclides in fallout from nuclear tests conducted at the Nevada Test Site (NTS) and sites outside of the United States (global fallout); estimates risk of developing thyroid cancer from that exposure; and provides an estimate of probability of causation, sometimes called assigned share (PC/AS), for individuals who have been diagnosed with thyroid cancer.

Plutonium as a chronomarker in Australian and New Zealand sediments: a comparison with (137)Cs.

PubMed

Hancock, G J; Leslie, C; Everett, S E; Tims, S G; Brunskill, G J; Haese, R

2011-10-01

The construction of high resolution chronologies of sediment profiles corresponding to the last 50-100 years usually entails the measurement of fallout radionuclides (210)Pb and (137)Cs. The anthropogenic radionuclide, (137)Cs, originating from atmospheric nuclear weapons testing can provide an important "first appearance" horizon of known age (1954-1955), providing much-needed validation for the sometimes uncertain interpretations associated with (210)Pb geochronology. However, while (137)Cs usually provides a strong signal in sediment in the northern hemisphere, total fallout of (137)Cs in the southern hemisphere was only 25% that of the north and the low activities of (137)Cs seen in Australian and New Zealand sediments can make its horizon of first appearance somewhat arguable. Low (137)Cs fallout also limited the size of the 1963-1964 fallout peak, a peak that is usually seen in northern hemisphere sediment profiles but is often difficult to discern south of the equator. This paper shows examples of the use of nuclear weapons fallout Pu as a chronomarker in sediment cores from Australia (3 sites) and New Zealand (1 site). The Pu profiles of five cores are examined and compared with the corresponding (137)Cs profiles and (210)Pb geochronologies. We find that Pu has significant advantages over (137)Cs, including greater measurement sensitivity using alpha spectrometry and mass spectrometric techniques compared to (137)Cs measurements by gamma spectrometry. Moreover, Pu provides additional chronomarkers associated with changes in the Pu isotopic composition of fallout during the 1950s and 1960s. In particular, the (238)Pu/(239+240)Pu activity ratio shows distinct shifts in the early 1950s and the mid to late 1960s, providing important known-age horizons in southern hemisphere sediments. For estuarine and near-shore sediments Pu sometimes has another significant advantage over (137)Cs due to its enrichment in bottom sediment relative to (137)Cs resulting from the more efficient scavenging of dissolved Pu in seawater by sediment particles. Copyright © 2009 Elsevier Ltd. All rights reserved.

Distribution of oceanic 137Cs from the Fukushima Dai-ichi Nuclear Power Plant simulated numerically by a regional ocean model.

PubMed

Tsumune, Daisuke; Tsubono, Takaki; Aoyama, Michio; Hirose, Katsumi

2012-09-01

Radioactive materials were released to the environment from the Fukushima Dai-ichi Nuclear Power Plant as a result of the reactor accident after the Tohoku earthquake and tsunami of 11 March 2011. The measured (137)Cs concentration in a seawater sample near the Fukushima Dai-ichi Nuclear Power Plant site reached 68 kBq L(-1) (6.8 × 10(4)Bq L(-1)) on 6 April. The two major likely pathways from the accident site to the ocean existed: direct release of high radioactive liquid wastes to the ocean and the deposition of airborne radioactivity to the ocean surface. By analysis of the (131)I/(137)Cs activity ratio, we determined that direct release from the site contributed more to the measured (137)Cs concentration than atmospheric deposition did. We then used a regional ocean model to simulate the (137)Cs concentrations resulting from the direct release to the ocean off Fukushima and found that from March 26 to the end of May the total amount of (137)Cs directly released was 3.5 ± 0.7 PBq ((3.5 ± 0.7) × 10(15)Bq). The simulated temporal change in (137)Cs concentrations near the Fukushima Daini Nuclear Power Plant site agreed well with observations. Our simulation results showed that (1) the released (137)Cs advected southward along the coast during the simulation period; (2) the eastward-flowing Kuroshio and its extension transported (137)C during May 2011; and (3) (137)Cs concentrations decreased to less than 10 BqL(-1) by the end of May 2011 in the whole simulation domain as a result of oceanic advection and diffusion. We compared the total amount and concentration of (137)Cs released from the Fukushima Dai-ichi reactors to the ocean with the (137)Cs released to the ocean by global fallout. Even though the measured (137)Cs concentration from the Fukushima accident was the highest recorded, the total released amount of (137)Cs was not very large. Therefore, the effect of (137)Cs released from the Fukushima Dai-ichi reactors on concentration in the whole North Pacific was smaller than that of past release events such as global fallout, and the amount of (137)Cs expected to reach other oceanic basins is negligible comparing with the past radioactive input. Copyright © 2011 Elsevier Ltd. All rights reserved.

Does the Fukushima NPP disaster affect the caesium activity of North Atlantic Ocean fish?

NASA Astrophysics Data System (ADS)

Kanisch, G.; Aust, M.-O.

2013-08-01

Fillet samples of marine fish collected from the East/West Greenland currents (GC) and from the Baltic Sea (BS) have been investigated by gamma-ray spectrometry within the regular German monitoring programme. In samples of the second half of 2011, 134Cs traces have been detected that are suggested to originate from the Fukushima fallout that was deposited in March/April 2011 over the northern North Atlantic and accumulated by fish. The radionuclide 134Cs (half-life 2 yr) was indeed detected with quite small activities at about 0.0036 Bq kg-1 w.w. Existing box models describing the transport of Cs within seawater boxes of the northeast Atlantic allowed for estimation of 134Cs contributions from other sources, i.e. from the Chernobyl fallout and from discharges by the two major European nuclear reprocessing plants; both were negligible around Greenland, while for the Chernobyl fallout a small 134Cs background contribution to BS fish was estimated. Model results confirmed the level of 134C measured in BS fish and showed its maximum to have occurred in winter 2011/2012 followed by a continuous decrease. It was also determined that 134Cs activity, but not that of 134Cs, showed a significant negative correlation with sampling depth (150-400 m) of GC fish; this strengthens our Fukushima fallout assumption. As a result, the Fukushima fallout in these sea areas only marginally enhanced (GC: 4%; BS: 0.1%) pre-Fukushima levels of individual dose rates received by human fish consumers; the addition was around 0.001 μSv following the consumption of 10 kg of fish per year, which is not expected to cause concern according to present guidelines for radiation protection.

Does the Fukushima NPP disaster affect the caesium activity of North Atlantic Ocean fish?

NASA Astrophysics Data System (ADS)

Kanisch, G.; Aust, M.-O.

2013-03-01

Fillet samples of marine fish collected from the East/West Greenland current (GC) and from the Baltic Sea (BS), have been investigated by gamma-ray spectrometry within the regular German monitoring program. In samples of the second half of 2011 134Cs traces have been detected, suggested to originate from the Fukushima fallout being deposited in March/April 2011 over the northern North Atlantic and accumulated by fish. The radionuclide 134Cs (half-live 2 yr) was indeed detected with quite small activities at about 0.0036 Bq kg-1 w.w. Existing box-models describing the transport of Cs within seawater boxes of the NE Atlantic allowed estimating that 134Cs contributions from other sources, i.e. from the Chernobyl fallout and from discharges by the two major European nuclear reprocessing plants, both were negligible around Greenland, while for the Chernobyl fallout a small 134Cs background contribution to BS fish was estimated. Model results confirmed the level of 134Cs measured in BS fish and showed its maximum to have occurred in winter 2011/2012 followed by a continuous decrease. It was also determined that 134Cs activity, but not that of 134Cs, showed a significant negative correlation with sampling depth (150-400 m) of GC fish; this strengthens our Fukushima fallout assumption. As a result, the Fukushima fallout in these sea areas only marginally enhanced (GC: 4%; BS: 0.1%) pre-Fukushima levels of individual dose rates received by human fish consumers; the addition was around 0.001 μSv following the consumption of 10 kg fish per year, which is not expected to cause concern according to present guidelines for radiation protection.

Nuclear cartography: patterns in binding energies and subatomic structure

NASA Astrophysics Data System (ADS)

Simpson, E. C.; Shelley, M.

2017-11-01

Nuclear masses and binding energies are some of the first nuclear properties met in high school physics, and can be used to introduce radioactive decays, fusion, and fission. With relatively little extension, they can also illustrate fundamental concepts in nuclear physics, such as shell structure and pairing, and to discuss how the elements around us were formed in stars. One way of visualising these nuclear properties is through the nuclide chart, which maps all nuclides as a function of their proton and neutron numbers. Here we use the nuclide chart to illustrate various aspects of nuclear physics, and present 3D visualisations of it produced as part of the binding blocks project.

The behavior of U- and Th-series nuclides in the estuarine environment

USGS Publications Warehouse

Swarzenski, P.W.; Porcelli, D.; Andersson, P.S.; Smoak, J.M.

2003-01-01

Rivers carry the products of continental weathering, and continuously supply the oceans with a broad range of chemical constituents. This erosional signature is, however, uniquely moderated by biogeochemical processing within estuaries. Estuaries are commonly described as complex filters at land-sea margins, where significant transformations can occur due to strong physico-chemical gradients. These changes differ for different classes of elements, and can vary widely depending on the geographic location. U- and Th-series nuclides include a range of elements with vastly different characteristics and behaviors within such environments, and the isotopic systematics provide methods for investigating the transport of these nuclides and other analog species across estuaries and into the coastal ocean.

7Be and hydrological model for more efficient implementation of erosion control measure

NASA Astrophysics Data System (ADS)

Al-Barri, Bashar; Bode, Samuel; Blake, William; Ryken, Nick; Cornelis, Wim; Boeckx, Pascal

2014-05-01

Increased concern about the on-site and off-site impacts of soil erosion in agricultural and forested areas has endorsed interest in innovative methods to assess in an unbiased way spatial and temporal soil erosion rates and redistribution patterns. Hence, interest in precisely estimating the magnitude of the problem and therefore applying erosion control measures (ECM) more efficiently. The latest generation of physically-based hydrological models, which fully couple overland flow and subsurface flow in three dimensions, permit implementing ECM in small and large scales more effectively if coupled with a sediment transport algorithm. While many studies focused on integrating empirical or numerical models based on traditional erosion budget measurements into 3D hydrological models, few studies evaluated the efficiency of ECM on watershed scale and very little attention is given to the potentials of environmental Fallout Radio-Nuclides (FRNs) in such applications. The use of FRN tracer 7Be in soil erosion/deposition research proved to overcome many (if not all) of the problems associated with the conventional approaches providing reliable data for efficient land use management. This poster will underline the pros and cones of using conventional methods and 7Be tracers to evaluate the efficiency of coconuts dams installed as ECM in experimental field in Belgium. It will also outline the potentials of 7Be in providing valuable inputs for evolving the numerical sediment transport algorithm needed for the hydrological model on field scale leading to assess the possibility of using this short-lived tracer as a validation tool for the upgraded hydrological model on watershed scale in further steps. Keywords: FRN, erosion control measures, hydrological modes

Radionuclides deposition and fine sediment transport in a forested watershed, central Japan

NASA Astrophysics Data System (ADS)

Nam, S.; Gomi, T.; Kato, H.; Tesfaye, T.; Onda, Y.

2011-12-01

We investigated radionuclides deposition and fine sediment transport in a 13 ha headwater watershed, Tochigi prefecture, located in 98.94 km north of Tokyo. The study site was within Karasawa experimental forest, Tokyo University of Agriculture and Technology. We conducted fingerprinting approach, based on the activities of fallout radionuclides, including caesium-134 (Cs-134) caesium-137 (Cs-137) and excess lead-210 (Pb-210ex). For indentifying specific sources of fine sediment, we sampled tree, soil on forested floor, soil on logging road surface, stream bed and stream banks. We investigated the radionuclides (i.e., as Cs-134, Cs-137 and Pb-210ex) deposition on tree after accident of nuclear power plants on March 11, 2011. We sampled fruits, leaves, branches, stems, barks on Japanese cedar (Sugi) and Japanese cypress (Hinoki). To analyze the samples, gammaray spectrometry was performed at a laboratory at the University of Tsukuba (Tsukuba City, Japan) using n-type coaxial low-energy HPGe gamma detectors (EGC-200-R and EGC25-195-R of EURYSIS Co., Lingolsheim, France) coupled with a multichannel analyzer. We also collected soil samples under the forest canopy in various soil depths from 2, 5, 10, 20, 30 cm along transect of hillslopes. Samples at forest road were collected road segments crossing on the middle section of monitoring watersheds. Fine sediment transport in the streams were collected at the outlet of 13 ha watersheds using integrated suspended sediment samplers. This study indicates the some portion of radio nuclide potentially remained on the tree surface. Part of the deposited radionuclides attached to soil particles and transported to the streams. Most of the fine sediment can be transported on road surface and/or near stream side (riparian zones).

Programmed gradient descent biosorption of strontium ions by Saccaromyces cerevisiae and ashing analysis: A decrement solution for nuclide and heavy metal disposal.

PubMed

Liu, Mingxue; Dong, Faqin; Zhang, Wei; Nie, Xiaoqin; Sun, Shiyong; Wei, Hongfu; Luo, Lang; Xiang, Sha; Zhang, Gege

2016-08-15

One of the waste disposal principles is decrement. The programmed gradient descent biosorption of strontium ions by Saccaromyces cerevisiae regarding bioremoval and ashing process for decrement were studied in present research. The results indicated that S. cerevisiae cells showed valid biosorption for strontium ions with greater than 90% bioremoval efficiency for high concentration strontium ions under batch culture conditions. The S. cerevisiae cells bioaccumulated approximately 10% of strontium ions in the cytoplasm besides adsorbing 90% strontium ions on cell wall. The programmed gradient descent biosorption presented good performance with a nearly 100% bioremoval ratio for low concentration strontium ions after 3 cycles. The ashing process resulted in a huge volume and weight reduction ratio as well as enrichment for strontium in the ash. XRD results showed that SrSO4 existed in ash. Simulated experiments proved that sulfate could adjust the precipitation of strontium ions. Finally, we proposed a technological flow process that combined the programmed gradient descent biosorption and ashing, which could yield great decrement and allow the supernatant to meet discharge standard. This technological flow process may be beneficial for nuclides and heavy metal disposal treatment in many fields. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of the Molecular Adsorber Coating Technology on the Ionospheric Connection Explorer Program

NASA Technical Reports Server (NTRS)

Abraham, Nithin S.; Hasegawa, Mark M.; Secunda, Mark S.

2016-01-01

The Molecular Adsorber Coating (MAC) is a zeolite based highly porous coating technology that was developed by NASA Goddard Space Flight Center (GSFC) to capture outgassed contaminants, such as plastics, adhesives, lubricants, silicones, epoxies, potting compounds, and other similar materials. This paper describes the use of the MAC technology to address molecular contamination concerns on NASAs Ionospheric Connection Explorer (ICON) program led by the University of California (UC) Berkeleys Space Sciences Laboratory. The sprayable paint technology was applied onto plates that were installed within the instrument cavity of ICONs Far Ultraviolet Imaging Spectrograph (FUV). However, due to the instruments particulate sensitivity, the coating surface was vibrationally cleaned through simulated acoustics to reduce the risk of particle fall-out contamination. This paper summarizes the coating application efforts on the FUV adsorber plates, the simulated laboratory acoustic level cleaning test methods, particulation characteristics, and future plans for the MAC technology.

Application of the Molecular Adsorber Coating technology on the Ionospheric Connection Explorer program

NASA Astrophysics Data System (ADS)

Abraham, Nithin S.; Hasegawa, Mark M.; Secunda, Mark S.

2016-09-01

The Molecular Adsorber Coating (MAC) is a zeolite based highly porous coating technology that was developed by NASA Goddard Space Flight Center (GSFC) to capture outgassed contaminants, such as plastics, adhesives, lubricants, silicones, epoxies, potting compounds, and other similar materials. This paper describes the use of the MAC technology to address molecular contamination concerns on NASA's Ionospheric Connection Explorer (ICON) program led by the University of California (UC) Berkeley's Space Sciences Laboratory. The sprayable paint technology was applied onto plates that were installed within the instrument cavity of ICON's Far Ultraviolet Imaging Spectrograph (FUV). However, due to the instrument's particulate sensitivity, the coating surface was vibrationally cleaned through simulated acoustics to reduce the risk of particle fall-out contamination. This paper summarizes the coating application efforts on the FUV adsorber plates, the simulated laboratory acoustic level cleaning test methods, particulation characteristics, and future plans for the MAC technology.

Reactor-released radionuclides in Susquehanna River sediments

USGS Publications Warehouse

Olsen, C.R.; Larsen, I.L.; Cutshall, N.H.; Donoghue, J.F.; Bricker, O.P.; Simpson, H.J.

1981-01-01

Three Mile Island (TMI) and Peach Bottom (PB) reactors have introduced 137Cs, 134Cs, 60Co, 58Co and several other anthropogenic radionuclides into the lower Susquehanna River. Here we present the release history for these nuclides (Table 1) and radionuclide concentration data (Table 2) for sediment samples collected in the river and upper portions of the Chesapeake Bay (Fig. 1) within a few months after the 28 March 1979 loss-of-coolant-water problem at TMI. Although we found no evidence for nuclides characteristic of a ruptured fuel element, we did find nuclides characteristic of routine operations. Despite the TMI incident, more than 95% of the total 134Cs input to the Susquehanna has been a result of controlled low-level releases from the PB site. 134Cs activity released into the river is effectively trapped by sediments with the major zones of reactor-nuclide accumulation behind Conowingo Dam and in the upper portions of Chesapeake Bay. The reported distributions document the fate of reactor-released radionuclides and their extent of environmental contamination in the Susquehanna-Upper Chesapeake Bay System. ?? 1981 Nature Publishing Group.

A Dynamic Approach to Monitoring Particle Fallout in a Cleanroom Environment

NASA Technical Reports Server (NTRS)

Perry, Radford L., III

2010-01-01

This slide presentation discusses a mathematical model to monitor particle fallout in a cleanroom. "Cleanliness levels" do not lead to increases with regards to cleanroom type or time because the levels are not linear. Activity level, impacts the cleanroom class. The numerical method presented leads to a simple Class-hour formulation, that allows for dynamic monitoring of the particle using a standard air particle counter.

Photographs and Pamphlet about Nuclear Fallout. The Constitution Community: Postwar United States (1945 to Early 1970s).

ERIC Educational Resources Information Center

Lawlor, John M., Jr.

In August 1945, the United States unleashed an atomic weapon against the Japanese at Hiroshima and Nagasaki and brought an end to World War II. These bombs killed in two ways -- by the blast's magnitude and resulting firestorm, and by nuclear fallout. After the Soviet Union exploded its first atom bomb in 1949, the Cold War waged between the two…

Impact Analysis of Age on Fallout Fatality Estimations for IND Scenarios

DTIC Science & Technology

2017-11-30

management of the acute radiation syndrome : recommendations of the Strategic National Stockpile Radiation Working Group. Ann Intern Med 140: 1037-51...dependent radiation dose response for acute effects was evaluated in detail. The analysis included data from animal studies, radiation oncology, and other...probability of 60-day mortality (assuming no treatment) for acute radiation exposure. This model has been adapted to account for protracted fallout

External radiation in Dolon village due to local fallout from the first USSR atomic bomb test in 1949.

PubMed

Imanaka, Tetsuji; Fukutani, Satoshi; Yamamoto, Masayoshi; Sakaguchi, Aya; Hoshi, Masaharu

2006-02-01

Dolon village, located about 60 km from the border of the Semipalatinsk Nuclear Test Site, is known to be heavily contaminated by local fallout from the first USSR atomic bomb test in 1949. External radiation in Dolon was evaluated based on recent 137Cs data in soil and calculation of temporal change in the fission product composition. After fitting a log-normal distribution to the soil data, a 137Cs deposition of 32 kBq m-2, which corresponds to the 90th-percentile of the distribution, was tentatively chosen as a value to evaluate the radiation situation in 1949. Our calculation indicated that more than 95% of the cumulative dose for 50 y had been delivered within 1 y after the deposition. The resulting cumulative dose for 1 y after the deposition, normalized to the initial contamination containing 1 kBq m-2 of 137Cs, was 15.6 mGy, assuming a fallout arrival time of 3 h and a medium level of fractionation. Finally, 0.50 Gy of absorbed dose in air was derived as our tentative estimate for 1-year cumulative external dose in Dolon due to local fallout from the first USSR test in 1949.

ESR dosimetry study of population in the vicinity of the Semipalatinsk Nuclear Test Site

PubMed Central

Zhumadilov, Kassym; Ivannikov, Alexander; Stepanenko, Valeriy; Zharlyganova, Dinara; Toyoda, Shin; Zhumadilov, Zhaxybay; Hoshi, Masaharu

2013-01-01

A tooth enamel electron spin resonance (ESR) dosimetry study was carried out with the purpose of obtaining the individual absorbed radiation doses of population from settlements in the Semipalatinsk region of Kazakhstan, which was exposed to radioactive fallout traces from nuclear explosions in the Semipalatinsk Nuclear Test Site and Lop Nor test base, China. Most of the settlements are located near the central axis of radioactive fallout trace from the most contaminating surface nuclear test, which was conducted on 29 August 1949, with the maximum detected excess dose being 430 ± 93 mGy. A maximum dose of 268 ± 79 mGy was determined from the settlements located close to radioactive fallout trace resulting from surface nuclear tests on 24 August 1956 (Ust-Kamenogorsk, Znamenka, Shemonaikha, Glubokoe, Tavriya and Gagarino). An accidental dose of 56 ± 42 mGy was found in Kurchatov city residents located close to fallout trace after the nuclear test on 7 August 1962. This method was applied to human tooth enamel to obtain individual absorbed doses of residents of the Makanchi, Urdzhar and Taskesken settlements located near the Kazakhstan–Chinese border due to the influence of nuclear tests (1964–1981) at Lop Nor. The highest dose was 123 ± 32 mGy. PMID:23404205

ESR dosimetry study of population in the vicinity of the Semipalatinsk Nuclear Test Site.

PubMed

Zhumadilov, Kassym; Ivannikov, Alexander; Stepanenko, Valeriy; Zharlyganova, Dinara; Toyoda, Shin; Zhumadilov, Zhaxybay; Hoshi, Masaharu

2013-07-01

A tooth enamel electron spin resonance (ESR) dosimetry study was carried out with the purpose of obtaining the individual absorbed radiation doses of population from settlements in the Semipalatinsk region of Kazakhstan, which was exposed to radioactive fallout traces from nuclear explosions in the Semipalatinsk Nuclear Test Site and Lop Nor test base, China. Most of the settlements are located near the central axis of radioactive fallout trace from the most contaminating surface nuclear test, which was conducted on 29 August 1949, with the maximum detected excess dose being 430 ± 93 mGy. A maximum dose of 268 ± 79 mGy was determined from the settlements located close to radioactive fallout trace resulting from surface nuclear tests on 24 August 1956 (Ust-Kamenogorsk, Znamenka, Shemonaikha, Glubokoe, Tavriya and Gagarino). An accidental dose of 56 ± 42 mGy was found in Kurchatov city residents located close to fallout trace after the nuclear test on 7 August 1962. This method was applied to human tooth enamel to obtain individual absorbed doses of residents of the Makanchi, Urdzhar and Taskesken settlements located near the Kazakhstan-Chinese border due to the influence of nuclear tests (1964-1981) at Lop Nor. The highest dose was 123 ± 32 mGy.

Synthetic fibers in atmospheric fallout: A source of microplastics in the environment?

PubMed

Dris, Rachid; Gasperi, Johnny; Saad, Mohamed; Mirande, Cécile; Tassin, Bruno

2016-03-15

Sources, pathways and reservoirs of microplastics, plastic particles smaller than 5mm, remain poorly documented in an urban context. While some studies pointed out wastewater treatment plants as a potential pathway of microplastics, none have focused on the atmospheric compartment. In this work, the atmospheric fallout of microplastics was investigated in two different urban and sub-urban sites. Microplastics were collected continuously with a stainless steel funnel. Samples were then filtered and observed with a stereomicroscope. Fibers accounted for almost all the microplastics collected. An atmospheric fallout between 2 and 355 particles/m(2)/day was highlighted. Registered fluxes were systematically higher at the urban than at the sub-urban site. Chemical characterization allowed to estimate at 29% the proportion of these fibers being all synthetic (made with petrochemicals), or a mixture of natural and synthetic material. Extrapolation using weight and volume estimates of the collected fibers, allowed a rough estimation showing that between 3 and 10 tons of fibers are deposited by atmospheric fallout at the scale of the Parisian agglomeration every year (2500 km(2)). These results could serve the scientific community working on the different sources of microplastic in both continental and marine environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Coagulation behavior of humic acid in aqueous solutions containing Cs+, Sr2+ and Eu3+: DLS, EEM and MD simulations.

PubMed

Tan, Liqiang; Tan, Xiaoli; Mei, Huiyang; Ai, Yuejie; Sun, Lu; Zhao, Guixia; Hayat, Tasawar; Alsaedi, Ahmed; Chen, Changlun; Wang, Xiangke

2018-05-01

The coagulation behaviors of humic acid (HA) with Cs + (10-500 mM), Sr 2+ (0.8-10.0 mM) and Eu 3+ (0.01-1.0 mM) at different pH values (2.8, 7.1 and 10.0) were acquired through a dynamic light scattering (DLS) technique combined with spectroscopic analysis and molecular dynamic (MD) simulations. The coagulation rate and the average hydrodynamic diameter () increased significantly as the concentration of nuclides increased. could be scaled to time t as ∝ t a at higher Sr 2+ concentrations, which shows that HA coagulation is consistent with the diffusion-limited colloid aggregation (DLCA) model. Trivalent Eu 3+ induced HA coagulation at a much lower concentration than bivalent Sr 2+ and monovalent Cs + . The coagulation value ratio of Sr 2+ and Eu 3+ to Cs + is almost proportional to Z -6 , indicating that the HA coagulation process is generally consistent with the Schulze-Hardy rule. Spectroscopic analysis indicated that the complexation between nuclides and carboxylic/phenolic groups of HA molecules played important roles in the coagulation of HA. MD modelling suggested that Sr 2+ and Eu 3+ ions increased the coagulation process through the formation of intra- or inter-molecular bridges between negatively charged HA molecules, whereas for Cs + , no inter-molecular bridges were formed. This work offers new insight into the interactions between HA and radionuclides and provides a prediction for the roles of HA in the transportation and elimination of radionuclides in severely polluted environments. Copyright © 2018 Elsevier Ltd. All rights reserved.

Including Deposition Rate in Models of Cosmogenic Nuclide Accumulation in Fluvial Sediments to Improve Terrace Abandonment Ages

NASA Astrophysics Data System (ADS)

Norton, K. P.; Wang, N.; Van Dissen, R. J.; Little, T.

2017-12-01

Fluvial sediments are archives of the erosional, transport, and depositional processes occurring in the catchment. Terraces become robust markers for geomorphic analysis if their time of abandonment can be determined. Methods such as OSL can determine burial ages for fine grained sediments within the terrace fill but may not be directly related to the terrace abandonment age. Cosmogenic nuclides can be used to determine exposure ages for geologically young terraces but the surface being dated may have been subsequently eroded and the material itself may have been deposited with an inherited nuclide concentration. To deal with this problem, many researchers collect multiple samples with depth to model the depth-dependent nuclide concentration to help constrain inheritance and post-depositional erosion. It is often, however, assumed that the entire sediment pile accumulated instantaneously. In this submission, we present the results of a depth profile model that incorporates sediment accumulation rate to improve terrace age estimates. We test this model on fault-offset river terraces near Kaikoura, New Zealand. We measured depth profiles of OSL ages and cosmogenic nuclide concentrations of two late Quaternary terraces that are offset by up to 800 m across the Kekerengu Fault. OSL ages and dated tephras in the overlying loess provide minimum age constraints for both terraces while OSL ages of fine-grained sediments within the fill provide depositional ages. The predicted sedimentation rates for the terraces are as high as 0.5m/yr, consistent with geologically instantaneous deposition. Modelled abandonment ages from cosmogenic nuclides for the terraces are consistent with OSL and tephra constraints at 9.7 +/- 3.8 ka and 30.4 +/- 2.1 ka, respectively. These terrace abandonment ages yield dextral slip rates of 18.5-20.5 mm/yr and 25-28 mm/yr, respectively, consistent with the rapid slip rate on the adjacent Hope Fault.

Nuclear Data Sheets for A = 84

NASA Astrophysics Data System (ADS)

Abriola, Daniel; Bostan, Melih; Erturk, Sefa; Fadil, Manssour; Galan, Monica; Juutinen, Sakari; Kibédi, Tibor; Kondev, Filip; Luca, Aurelian; Negret, Alexandru; Nica, Ninel; Pfeiffer, Bernd; Singh, Balraj; Sonzogni, Alejandro; Timar, Janos; Tuli, Jagdish; Venkova, Tsanka; Zuber, Kazimierz

2009-11-01

The evaluated spectroscopic data are presented for 12 known nuclides of mass 84 (Ga, Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo). Except for the stable nuclides 84Sr and 84Kr, extensive new data are available for all the other nuclides since the 1997 evaluation by J.K. Tuli (1997Tu02) of A = 84 nuclides. Many precise Penning-trap mass measurements since AME-2003 for A = 84 nuclides (2009Re03,2008Ha23,2008We10,2007Ke09,2006Ka48,2006De36,2006Ri15) have resulted in improved Q values and separation energies. However, many deficiencies still remain. Some examples are given below. Excited-state data for 84Ga and 84As are nonexistent, and those for 84Ge are scarce. The radioactive decay schemes of 84Ga, 84Ge, 84Se, 84Y (39.5 min), 84Y (4.6 s), 84Zr and 84Nb suffer from incompleteness and that for 84Mo decay is not known at all. The energy ordering of the two activities (39.5 min and and 4.6 s) of 84Y is not well established, although, high-spin with tentative spin-parity of (6+) is adopted here as the ground state of 84Y based on weak arguments. From a conference report published in 2000, it is clear that extensive experiments were done to investigate decays of 84Zr and 84Y, but details of these studies never appeared in literature and none were made available to the evaluators when requested from original authors. This evaluation was carried out as part of ENSDF workshop for Nuclear Structure and Decay Data Evaluators, organized and hosted by the "Horia Hulubei" National Institute for Physics and Nuclear Engineering, Bucharest, Romania during March 30, 2009 - April 3, 2009. Names of the evaluators principally responsible for evaluation of individual nuclides are given under the respective Adopted data sets.

Cosmogenic nuclide production within the atmosphere and long period comets

NASA Astrophysics Data System (ADS)

Overholt, Andrew C.

The Earth is constantly bombarded by cosmic rays. These high energy particles collide with target nuclei, producing a shower of secondary particles. These secondaries contribute significantly to the radiation background at sea level and in the atmosphere, as well as producing rare cosmogenic nuclides. This contribution is variable over long time scales as astrophysical events change the cosmic ray flux incident on the Earth. Our work re-examines a previously proposed climate effect of increased cosmic ray flux due to galactic location. Although our work does not support this effect, cosmic ray secondaries remain a threat to terrestrial biota. We calculate the cosmogenic neutron flux within the atmosphere as a function of primary spectrum. This work is pivotal in determining the radiation dose due to any arbitrary astrophysical event where the primary spectrum is known. Additionally, this work can be used to determine the cosmogenic nuclide production from such an event. These neutrons are the fundamental source of cosmogenic nuclides within our atmosphere and extraterrestrial matter. We explore the idea that excursions in 14C and 10Be abundances in the atmosphere may arise from direct deposition by long-period comet impacts, and those in 26Al from any bolide. We find that the amount of nuclide mass on large long-period comets entering the Earth's atmosphere may be sufficient for creating anomalies in the records of 14C and 10Be from past impacts. In particular, the estimated mass of the proposed Younger Dryas comet is consistent with its having deposited sufficient isotopes to account for recorded nuclide increases at that time. The 26Al/10Be ratio is much larger in extraterrestrial objects than in the atmosphere, and so, we note that measuring this ratio in ice cores is a suitable further test for the Younger Dryas impact hypothesis. This portion of our work may be used to find possible impact events in the geologic record as well as determination of a large bolide impact rate.

Long-term Glacial History of the West Antarctic Ice Sheet from Cosmogenic Nuclides in a Subglacial Bedrock Core

NASA Astrophysics Data System (ADS)

Spector, P. E.; Stone, J.; Hillebrand, T.; Gombiner, J. H.

2017-12-01

To investigate the response of the West Antarctic Ice Sheet (WAIS) to climatic conditions warmer than present, we are analyzing cosmogenic nuclides in a bedrock core from beneath 150 m of ice at a site near the Pirrit Hills. Our aim is to determine whether the WAIS has thinned in the past, exposing bedrock at this site, and if so, when. This will help to determine the vulnerability of the ice sheet to future warming, and identify climatic thresholds capable of inducing WAIS collapse. We selected a site where the ice-sheet surface lies at 1300 m, approximately halfway from the ice-sheet divide to the grounding line. We expect ice thickness at the site to reflect WAIS dynamics, rather than local meteorology or topography. Ice flow speeds are moderate and ice above the core site is thin enough to remain cold-based, limiting the possibility of subglacial erosion which would compromise the cosmogenic nuclide record. We targeted a subglacial ridge adjacent to an exposed granite nunatak. This lithology provides minerals suitable for analysis of multiple cosmogenic nuclides with different half-lives. Although we aimed to collect two cores from different depths to compare exposure histories, hydrofracture of the basal ice prevented us from reaching the bed at the first drill site. The second hole produced 5.5 m of discontinuous ice core above 8 m of bedrock core. Initial analyses of quartz from the bedrock show low levels of Be-10. Further analyses of Be-10, Al-26, Cl-36 and Ne-21 from the full length of the core will be required to determine whether this is because the surface has never been exposed, or because the cosmogenic nuclide profile has been truncated by glacial erosion. We will present comprehensive cosmogenic nuclide data, and discuss implications for WAIS deglaciation history, at the meeting. Supported by US National Science Foundation awards ANT-1142162 and PLR-1341728.

Nuclear Data Sheets for A=85

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Balraj; Chen, Jun

2014-02-01

Evaluated experimental data are presented for 13 known nuclides of mass 85 (Zn, Ga, Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo). Since the previous 1990 evaluation of A=85, {sup 85}Zn, {sup 85}Ga, {sup 85}Ge and {sup 85}nuclides are newly added here. Excited state data for {sup 85}Se, {sup 85}Zr have become available from radioactive decay and in–beam γ–ray studies. New and improved high–spin data are available for {sup 85}Br, {sup 85}Kr, {sup 85}Rb, {sup 85}Y, {sup 85}Nb and {sup 85}Mo. New direct and precise measurement of atomic masses of {sup 85}Ge, {sup 85}As, {sup 85}Se, {supmore » 85}Br, {sup 85}Rb, {sup 85}Zr, {sup 85}Nb and {sup 85}Mo have greatly improved the landscape of β decay–Q values and separation energies in this mass region. In spite of extensive experimental work on the isobaric nuclei of this mass chain several deficiencies remain. No excited states are known in {sup 85}Zn, {sup 85}Ga, {sup 85}As. Only a few excited state are assigned in {sup 85}Ge from {sup 85}Ga β– decay. From radioactivity studies, the decay schemes of {sup 85}Zn and {sup 85}Mo are not known, and those for {sup 85}Ga, {sup 85}Ge, {sup 85}As and 10.9–s isomer of {sup 85}Zr are incomplete. Level lifetimes are not known for excited states in {sup 85}Se, {sup 85}Br, {sup 85}Nb and {sup 85}Mo. The {sup 85}Tc nuclide has not been detected in fragmentation experiments at GANIL, alluding to its unbound nature for proton emission. The {sup 85}Kr, {sup 85}Rb, {sup 85}Sr, and {sup 85}Y nuclides remain the most extensively studied from many different reactions and decays. The evaluation of A=85 nuclides has been done after a span of 23 years, thus includes an extensive amount of new data for almost each nuclide. This work supersedes the data for A=85 nuclides presented in earlier full NDS publication by J. Tepel in 1980Te04 and a later one published in an update mode by H. Sievers in 1991Si01.« less

Iso standardization of theoretical activity evaluation method for low and intermediate level activated waste generated at nuclear power plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Makoto Kashiwagi; Garamszeghy, Mike; Lantes, Bertrand

Disposal of low-and intermediate-level activated waste generated at nuclear power plants is being planned or carried out in many countries. The radioactivity concentrations and/or total quantities of long-lived, difficult-to-measure nuclides (DTM nuclides), such as C-14, Ni-63, Nb-94, α emitting nuclides etc., are often restricted by the safety case for a final repository as determined by each country's safety regulations, and these concentrations or amounts are required to be known and declared. With respect to waste contaminated by contact with process water, the Scaling Factor method (SF method), which is empirically based on sampling and analysis data, has been applied asmore » an important method for determining concentrations of DTM nuclides. This method was standardized by the International Organization for Standardization (ISO) and published in 2007 as ISO21238 'Scaling factor method to determine the radioactivity of low and intermediate-level radioactive waste packages generated at nuclear power plants' [1]. However, for activated metal waste with comparatively high concentrations of radioactivity, such as may be found in reactor control rods and internal structures, direct sampling and radiochemical analysis methods to evaluate the DTM nuclides are limited by access to the material and potentially high personnel radiation exposure. In this case, theoretical calculation methods in combination with empirical methods based on remote radiation surveys need to be used to best advantage for determining the disposal inventory of DTM nuclides while minimizing exposure to radiation workers. Pursuant to this objective a standard for the theoretical evaluation of the radioactivity concentration of DTM nuclides in activated waste, is in process through ISO TC85/SC5 (ISO Technical Committee 85: Nuclear energy, nuclear technologies, and radiological protection; Subcommittee 5: Nuclear fuel cycle). The project team for this ISO standard was formed in 2011 and is composed of experts from 11 countries. The project team has been conducting technical discussions on theoretical methods for determining concentrations of radioactivity, and has developed the draft International Standard of ISO16966 'Theoretical activation calculation method to evaluate the radioactivity of activated waste generated at nuclear reactors' [2]. This paper describes the international standardization process developed by the ISO project team, and outlines the following two theoretical activity evaluation methods:? Point method? Range method. (authors)« less

A Physical Model of Cosmogenic Nuclide Production in Stony and Iron Meteoroids on the Basis of Simulation Experiments

NASA Astrophysics Data System (ADS)

Leya, I.; Lange, H.-J.; Michel, R.; Meltzow, B.; Herpers, U.; Busemann, H.; Wieler, R.; Dittrich-Hannen, B.; Suter, M.; Kubik, P. W.

1995-09-01

By extending and improving earlier model calculations [1-4] of cosmogenic nuclide production by GCR particles in extraterrestrial matter, we can now present a physical model without free parameters for a consistent description of GCR production rates in stony and iron meteoroids. The model takes explicitely into account p and n-induced reactions. GCR 4He particles are considered only approximately. It is based on depth-size and bulk-chemistry-dependent spectra of primary and secondary protons and of secondary neutrons calculated by HET and MORSE codes within the HERMES code system [5] and on the cross sections of the underlying reactions. Comprehensive and reliable sets of proton cross sections from thresholds up to 2.6 GeV exist now for many cosmogenic nuclides (see [6] for a review). For n-induced reactions the situation is not so good. Only a few data at low energies and practically no data at higher energies exist. GCR production of cosmogenic nuclides in stony meteoroids is already dominated by neutron-induced reactions for most meteoroid radii. In iron meteoroids neutrons are even more important because of the high mass numbers of the bulk and of consequently higher multiplicities for production of secondary neutrons. In order to overcome this problem, the necessary excitation functions of neutron-induced reactions were determined from experimental thick-target production rates by least-squares unfolding procedures using the code STAYS'L [7]. The data were produced in laboratory experiments under completely controlled conditions [8-11]. The unfolding procedure starts from guess functions (from threshold up to 900 MeV) based on all available experimental neutron cross sections and on theoretical ones calculated by the AREL [12] code which is a relativistic version of the hybrid model of pre-equilibrium reactions [13]. With the new neutron cross sections it is possible to describe simultanously all data from the simulation experiments with an accuracy of better than 10 % and to calculate consistent cosmogenic nuclide production rates in stony and iron meteoroids. The new model calculations are so far valid for 10Be, 26Al, 36Cl, 41Ca, 53Mn as well as He, Ne and Ar isotopes. The new theoretical production rates are compared with measured depth profiles in stony and iron meteorites and will be discussed with respect to primary GCR spectra and preatmospheric radii and exposure histories of stony and iron meteoroids. Acknowledgement: This work was partially supported by the Deutsche Forschungsgemeinschaft and the Swiss National Science Foundation. References: [1] Michel R. et al. (1991) Meteoritics, 26, 221-242. [2] Michel R. et al. (1995) Planet. Space Sci., in press. [3] Bhandari N. et al. (1993) GCA, 57, 2361-2375. [4] Herpers U. et al. (1995) Planet. Space Sci., in press. [5] Cloth P. et al. (1988) JUEL-2203. [6] Michel R. (1994) in Nuclear Data for Science and Technology (J. K. Dickens, ed.), 337-343, Am. Nucl. Soc., La Grange Park. [7] Perrey F. G. (1977) Code STAYS'L, NEA Data Bank, OECD Paris. [8] Michel R. et al. (1986) Nucl. Instr. Meth. Phys. Res., B16, 61-82. [9] Michel R. et al. (1989) Nucl. Instr. Meth. Phys. Res., B42, 76-100. [10] Michel R. et al. (1993) J. Radioanal. Nucl. Chem., 169, 13-25. [11] Michel R. et al. (1994) in Nuclear Data for Science and Technology (J. K. Dickens, ed.), 377-379, Am. Nucl. Soc., La Grange Park. [12] Blann M. (1994) Code AREL, personal communication to R. Michel. [13] Blann M. (1972) Phys. Rev. Lett., 27, 337-340.

Sources and transport of anthropogenic radionuclides in the Ob River system, Siberia

NASA Astrophysics Data System (ADS)

Cochran, J. Kirk; Moran, S. Bradley; Fisher, Nicholas S.; Beasley, Thomas M.; Kelley, James M.

2000-06-01

The potential sources of anthropogenic radionuclides to the Ob River system of western Siberia include global stratospheric fallout, tropospheric fallout from atomic weapons tests and releases from production and reprocessing facilities. Samples of water, suspended and bottom sediments collected in 1994 and 1995 have been used to characterize the sources and transport of 137Cs, Pu isotopes, 237Np and 129I through the system. For the radionuclides that associate with particles, isotope ratios provide clues to their sources, providing any geochemical fractionation can be taken into account. Activity ratios of 239,240Pu/ 137Cs in suspended sediments are lower than the global fallout ratio in the Irtysh River before its confluence with the Ob, comparable to fallout in the central reach of the Ob, and greater than the fallout values in the lower Ob and in the Taz River. This pattern mirrors the downriver decrease in dissolved organic carbon (DOC) concentrations. Laboratory adsorption experiments with Ob River sediment and water show that Kd values for Am (and presumably other actinides) are depressed by two orders of magnitude in the presence of Ob DOC concentrations, relative to values measured in DOC-free Ob water. Iodine and cesium Kd values show little or no (less than a factor of 2) dependence on DOC. Mixing plots using plutonium isotope ratios (atom ratios) show that Pu in suspended sediments of the Ob is a mixture of stratospheric global fallout at northern latitudes, tropospheric fallout from the former Soviet Union test site at Semipalatinsk and reprocessing of spent fuel at Tomsk-7. Plutonium from Semipalatinsk is evident in the Irtysh River above its confluence with the Tobal. Suspended sediment samples taken in the Ob above its confluence with the Irtysh indicate the presence of Pu derived from the Tomsk-7 reprocessing facilities. A mixing plot constructed using 237Np/ 239Pu vs. 240Pu/ 239Pu shows similar mixtures of stratospheric and tropospheric fallout, with the likely addition of inputs from reprocessing facilities and reactor operations. As with Pu/Cs ratios, Np/Pu ratios could be modified by differential geochemical behaviors of Np and Pu. Dissolved 129I only weakly interacts with particles in the Ob; size-fractionated sampling shows that the colloidal 129I fraction (defined as 1 kDa-0.2 μm) contains generally <5% relative to that passing a 0.2 μm filter. Iodine-129 concentrations decrease from 8.3×10 9 to 0.65×10 9 atoms l -1 through the Ob system toward the Kara Sea, with highest values in the Tobal River and lowest in the Taz River. The likely source of the elevated 129I in the Tobal is release from the production-reprocessing facilities at Mayak, and decreases downriver are predominantly due to dilution as the various tributaries with low 129I join the system. Fluxes of 129I to the lower Ob at Salekhard are <1% of the releases of this radionuclide from the nuclear fuel reprocessing facilities at Sellafield, UK and La Hague, France.

Skin dose from radionuclide contamination on clothing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, D.C.; Hussein, E.M.A.; Yuen, P.S.

1997-06-01

Skin dose due to radio nuclide contamination on clothing is calculated by Monte Carlo simulation of electron and photon radiation transport. Contamination due to a hot particle on some selected clothing geometries of cotton garment is simulated. The effect of backscattering in the surrounding air is taken into account. For each combination of source-clothing geometry, the dose distribution function in the skin, including the dose at tissue depths of 7 mg cm{sup -2} and 1,000 Mg cm{sup -2}, is calculated by simulating monoenergetic photon and electron sources. Skin dose due to contamination by a radionuclide is then determined by propermore » weighting of & monoenergetic dose distribution functions. The results are compared with the VARSKIN point-kernel code for some radionuclides, indicating that the latter code tends to under-estimate the dose for gamma and high energy beta sources while it overestimates skin dose for low energy beta sources. 13 refs., 4 figs., 2 tabs.« less

Observations of Fallout from the Fukushima Reactor Accident in San Francisco Bay Area Rainwater

PubMed Central

Norman, Eric B.; Angell, Christopher T.; Chodash, Perry A.

2011-01-01

We have observed fallout from the recent Fukushima Dai-ichi reactor accident in samples of rainwater collected in the San Francisco Bay area. Gamma ray spectra measured from these samples show clear evidence of fission products – 131,132I, 132Te, and 134,137Cs. The activity levels we have measured for these isotopes are very low and pose no health risk to the public. PMID:21957447

Military Knowledge Handbook for Commanders (Selected Section)

DTIC Science & Technology

1988-03-28

8217 Accession For NTIS GRA&I DTIC TAB 0l Unannoun ed 0] ju,.it . " t ation Distri’muti on/ Availabilit %Codes Dist cSpeial GRAPHICS DISCLAIMER...cloud layers, the energy of ray radiation on the ground will increase due to reflection effect of the cloud layers. Water surface, ice, accumulated... water flow can direct the radioactive fallout into defense works and water sources to worsen contaminations; radioactive fallout can easily be retained in

Characteristic of microplastics in the atmospheric fallout from Dongguan city, China: preliminary research and first evidence.

PubMed

Cai, Liqi; Wang, Jundong; Peng, Jinping; Tan, Zhi; Zhan, Zhiwei; Tan, Xiangling; Chen, Qiuqiang

2017-11-01

Microplastic pollution has exhibited a global distribution, including seas, lakes, rivers, and terrestrial environment in recent years. However, little attention was paid on the atmospheric environment, though the fact that plastic debris can escape as wind-blown debris was previously reported. Thus, characteristics of microplastics in the atmospheric fallout from Dongguan city were preliminarily studied. Microplastics of three different polymers, i.e., PE, PP, and PS, were identified. Diverse shapes of microplastics including fiber, foam, fragment, and film were found, and fiber was the dominant shape of the microplastics. SEM images illustrated that adhering particles, grooves, pits, fractures, and flakes were the common patterns of degradation. The concentrations of non-fibrous microplastics and fibers ranged from 175 to 313 particles/m 2 /day in the atmospheric fallout. Thus, dust emission and deposition between atmosphere, land surface, and aquatic environment were associated with the transportation of microplastics.

Fallout of Debris from Tornadic Thunderstorms: A Historical Perspective and Two Examples from VORTEX.

NASA Astrophysics Data System (ADS)

Snow, John T.; Wyatt, Amy Lee; McCarthy, Ann K.; Bishop, Eric K.

1995-10-01

Preliminary results of an investigation of debris lofted by tornadoes, its long-distance transport by thunderstorms, and its subsequent fallout are reported. The authors begin with a review of historical accounts, including the unique study of the 1984 Barneveld, Wisconsin, tornado by Anderson, which shows that long-distance transport and fallout of debris have occurred and that distances involved have been significant. The authors then report first-hand evidence of these phenomena in two events with F2 tornadoes: the Tuskahoma, Oklahorna, tornado of 25 April 1994 and the Gainesville, Texas, tornadoes of 26 April 1994. In both cases, traceable material in the form of canceled checks, bills-of-sale, invoices, and legal documents were reported to the authors, who were able to locate the source locations for several of these items. The authors close with some conjectures on the implications of these first findings.

Extended Monitoring of Radioactive Fallout from the Fukushima Reactor Incident in a Variety of Media

NASA Astrophysics Data System (ADS)

Thomas, Keenan; Norman, Eric; Smith, Al; Angell, Christopher; Chodash, Perry; Lo, Boris; Hurley, Donna; Chan, Yuen-Dat

2013-04-01

We have observed fallout from the Fukushima Dai-ichi reactor accident in March of 2011 in samples of rainwater and a variety of air filters collected in the San Francisco Bay area and Northern California. Gamma ray spectra measured from the rain samples showed clear evidence of fission products - 131,132I, 132Te, and 134,137Cs. The activity levels measured for these isotopes were very low and posed no health risk to the public or environment. Additional testing was performed upon these rainwater samples in 2012 to also investigate the presence of 90Sr-which was not detected and a detection limit was determined. Also presented will be a separate set of gamma ray measurements of Fukushima fallout that has been tracked on a variety of media-rainwater, air filters, and automobile filters; throughout 2011 and 2012.

Ambient airborne solids concentrations including volcanic ash at Hanford, Washington sampling sites subsequent to the Mount St. Helens eruption

NASA Technical Reports Server (NTRS)

Sehmel, G. A.

1982-01-01

Airborne solids concentrations were measured on a near daily basis at two Hanford, Washington sites after the eruption of Mount St. Helens on May 18, 1980. These sites are about 211 km east of Mount St. Helens. Collected airborne solids included resuspended volcanic ash plus normal ambient solids. Average airborne solids concentrations were greater at the Hanford meteorological station sampling site which is 24 km northwest of the Horn Rapids dam sampling site. These increased concentrations reflect the sampling site proximity to greater ash fallout depths. Both sites are in low ash fallout areas although the Hanford meteorological station site is closer to the greater ash fallout areas. Airborne solids concentrations were decreased by rain, but airborne solids concentrations rapidly increased as surfaces dried. Airborne concentrations tended to become nearly the same at both sampling sites only for July 12 and 13.

Radionuclides in tea and their behaviour in the brewing process.

PubMed

Zehringer, Markus; Kammerer, Franziska; Wagmann, Michael

2018-06-08

Tea plantations may be strongly affected by radioactive fallout. Tea plantations on the Turkish coast of the Black Sea were heavily contaminated by the fallout from the reactor fire at the Chernobyl nuclear power plant in 1986. Two years later, the contamination level was reduced by about 90%. When tea is brewed, the original contamination in the tea leaves is more or less leached into the tea water. While most of the radiocaesium (60-80%) is washed out by brewing, most of the radiostrontium remains in the leaves (70-80%). In food laws, a dilution factor of 40-50 is considered for tea brewing. Most laws only define limit values for radiocaesium. Radiostrontium is not specially regulated, even though its dose coefficients for ingestion are higher than the corresponding coefficients for radiocaesium. Radiostrontium in tea occurs primarily from global fallout (bomb tests from 1945-1965). Copyright © 2018. Published by Elsevier Ltd.

Fukushima Nuclear Accident Recorded in Tibetan Plateau Snow Pits

PubMed Central

Wang, Ninglian; Wu, Xiaobo; Kehrwald, Natalie; Li, Zhen; Li, Quanlian; Jiang, Xi; Pu, Jianchen

2015-01-01

The β radioactivity of snow-pit samples collected in the spring of 2011 on four Tibetan Plateau glaciers demonstrate a remarkable peak in each snow pit profile, with peaks about ten to tens of times higher than background levels. The timing of these peaks suggests that the high radioactivity resulted from the Fukushima nuclear accident that occurred on March 11, 2011 in eastern Japan. Fallout monitoring studies demonstrate that this radioactive material was transported by the westerlies across the middle latitudes of the Northern Hemisphere. The depth of the peak β radioactivity in each snow pit compared with observational precipitation records, suggests that the radioactive fallout reached the Tibetan Plateau and was deposited on glacier surfaces in late March 2011, or approximately 20 days after the nuclear accident. The radioactive fallout existed in the atmosphere over the Tibetan Plateau for about one month. PMID:25658094

Is there a role for nonsedating antihistamines in motion sickness? Fallout from space research may soon benefit your patients

NASA Technical Reports Server (NTRS)

Kohl, R. L.

1991-01-01

The rotating chair test, a novel research technique for simulating motion sickness, is used to study the effect of nonsedating oral antihistamines in preventing or forestalling motion sickness. After receiving terfenadine, astemizole, doxepin, or placebo, four groups of male volunteers were rotated at accelerating speed, and they made head movements out of the axis of rotation until they perceived that vomiting would occur if additional head movements were made. Those pretreated with doxepin or terfenadine experienced a statistically significant prophylactic effect, as measured by increased tolerance to Coriolis stimulation. This suggests that selective peripheral H1 antihistamine action may protect against motion sickness.

The CIELO collaboration: Progress in international evaluations of neutron reactions on Oxygen, Iron, Uranium and Plutonium

DOE PAGES

Chadwick, M. B.; Capote, R.; Trkov, A.; ...

2017-01-01

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies - 16O, 56Fe, 235;8U and 239Pu - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality.

The CIELO collaboration: Progress in international evaluations of neutron reactions on Oxygen, Iron, Uranium and Plutonium

NASA Astrophysics Data System (ADS)

Chadwick, M. B.; Capote, R.; Trkov, A.; Kahler, A. C.; Herman, M. W.; Brown, D. A.; Hale, G. M.; Pigni, M.; Dunn, M.; Leal, L.; Plompen, A.; Schillebeeck, P.; Hambsch, F.-J.; Kawano, T.; Talou, P.; Jandel, M.; Mosby, S.; Lestone, J.; Neudecker, D.; Rising, M.; Paris, M.; Nobre, G. P. A.; Arcilla, R.; Kopecky, S.; Giorginis, G.; Cabellos, O.; Hill, I.; Dupont, E.; Danon, Y.; Jing, Q.; Zhigang, G.; Tingjin, L.; Hanlin, L.; Xichao, R.; Haicheng, W.; Sin, M.; Bauge, E.; Romain, P.; Morillon, B.; Noguere, G.; Jacqmin, R.; Bouland, O.; De Saint Jean, C.; Pronyaev, V. G.; Ignatyuk, A.; Yokoyama, K.; Ishikawa, M.; Fukahori, T.; Iwamoto, N.; Iwamoto, O.; Kuneada, S.; Lubitz, C. R.; Palmiotti, G.; Salvatores, M.; Kodeli, I.; Kiedrowski, B.; Roubtsov, D.; Thompson, I.; Quaglioni, S.; Kim, H. I.; Lee, Y. O.; Koning, A. J.; Carlson, A.; Fischer, U.; Sirakov, I.

2017-09-01

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies - 16O, 56Fe, 235,8U and 239Pu - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality.

Methods of measuring radioactivity in the environment

NASA Astrophysics Data System (ADS)

Isaksson, Mats

In this thesis a variety of sampling methods have been utilised to assess the amount of deposited activity, mainly of 137Cs, from the Chernobyl accident and from the nuclear weapons tests. Starting with the Chernobyl accident in 1986 sampling of air and rain was used to determine the composition and amount of radioactive debris from this accident, brought to southern Sweden by the weather systems. The resulting deposition and its removal from urban areas was than studied through measurements on sewage sludge and water. The main part of the thesis considers methods of determining the amount of radiocaesium in the ground through soil sampling. In connection with soil sampling a method of optimising the sampling procedure has been developed and tested in the areas of Sweden which have a comparatively high amount of 137Cs from the Chernobyl accident. This method was then used in a survey of the activity in soil in Lund and Skane, divided between nuclear weapons fallout and fallout from the Chernobyl accident. By comparing the results from this survey with deposition calculated from precipitation measurements it was found possible to predict the deposition pattern over Skane for both nuclear weapons fallout and fallout from the Chernobyl accident. In addition, the vertical distribution of 137Cs has been modelled and the temporal variation of the depth distribution has been described.

Impact of Tumor Localization and Method of Preoperative Biopsy on Sentinel Lymph Node Mapping After Periareolar Nuclide Injection.

PubMed

Krammer, Julia; Dutschke, Anja; Kaiser, Clemens G; Schnitzer, Andreas; Gerhardt, Axel; Radosa, Julia C; Brade, Joachim; Schoenberg, Stefan O; Wasser, Klaus

2016-01-01

To evaluate whether tumor localization and method of preoperative biopsy affect sentinel lymph node (SLN) detection after periareolar nuclide injection in breast cancer patients. 767 breast cancer patients were retrospectively included. For lymphscintigraphy periareolar nuclide injection was performed and the SLN was located by gamma camera. Patient and tumor characteristics were correlated to the success rate of SLN mapping. SLN marking failed in 9/61 (14.7%) patients with prior vacuum-assisted biopsy and 80/706 (11.3%) patients with prior core needle biopsy. Individually evaluated, biopsy method (p = 0.4) and tumor localization (p = 0.9) did not significantly affect the SLN detection rate. Patients with a vacuum-assisted biopsy of a tumor in the upper outer quadrant had a higher odds ratio of failing in SLN mapping (OR 3.8, p = 0.09) compared to core needle biopsy in the same localization (OR 0.9, p = 0.5). Tumor localization and preoperative biopsy method do not significantly impact SLN mapping with periareolar nuclide injection. However, the failure risk tends to rise if vacuum-assisted biopsy of a tumor in the upper outer quadrant is performed.

Derivation of the Korean radwaste scaling factor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwang Yong Jee; Hong Joo Ahn; Se Chul Sohn

2007-07-01

The concentrations of several radionuclides in low and intermediate level radioactive waste (LILW) drums have to be determined before shipping to disposal facilities. A notice, by the Ministry of Science and Technology (MOST) of the Korean Government, related to the disposal of LILW drums came into effect at the beginning of 2005, with regards to a radionuclide regulation inside a waste drum. MOST allows for an indirect radionuclide assay using a scaling factor to measure the inventories due to the difficulty of nondestructively measuring the essential {alpha} and {beta}-emitting nuclides inside a drum. That is, a scaling factor calculated throughmore » a correlation of the {alpha} or {beta}-emitting nuclide (DTM, Difficult-To-Measure) with a {gamma}-emitting nuclide (ETM, Easy-To-Measure) which has systematically similar properties with DTM nuclides. In this study, radioactive wastes, such as spent resin and dry active waste which were generated at different sites of a PWR and a site of a PHWR type Korean NPP, were partially sampled and analyzed for regulated radionuclides by using radiochemical methods. According to a reactor type and a waste form, the analysis results of each radionuclide were classified. Korean radwaste scaling factor was derived from database of radionuclide concentrations. (authors)« less

Cosmogenic nuclides in the Martian surface: Constraints for sample recovery and transport

NASA Technical Reports Server (NTRS)

Englert, Peter A. J.

1988-01-01

Stable and radioactive cosmogenic nuclides and radiation damage effects such as cosmic ray tracks can provide information on the surface history of Mars. A recent overview on developments in cosmogenic nuclide research for historical studies of predominantly extraterrestrial materials was published previously. The information content of cosmogenic nuclides and radiation damage effects produced in the Martian surface is based on the different ways of interaction of the primary galactic and solar cosmic radiation (GCR, SCR) and the secondary particle cascade. Generally the kind and extent of interactions as seen in the products depend on the following factors: (1) composition, energy and intensity of the primary SCR and GCR; (2) composition, energy and intensity of the GCR-induced cascade of secondary particles; (3) the target geometry, i.e., the spatial parameters of Martian surface features with respect to the primary radiation source; (4) the target chemistry, i.e., the chemical composition of the Martian surface at the sampling location down to the minor element level or lower; and (5) duration of the exposure. These factors are not independent of each other and have a major influence on sample taking strategies and techniques.

Advection of Microphysical Scalars in Terminal Area Simulation System (TASS)

NASA Technical Reports Server (NTRS)

Ahmad, Nashat N.; Proctor, Fred H.

2011-01-01

The Terminal Area Simulation System (TASS) is a large eddy scale atmospheric flow model with extensive turbulence and microphysics packages. It has been applied successfully in the past to a diverse set of problems ranging from prediction of severe convective events (Proctor et al. 2002), tracking storms and for simulating weapons effects such as the dispersion and fallout of fission debris (Bacon and Sarma 1991), etc. More recently, TASS has been used for predicting the transport and decay of wake vortices behind aircraft (Proctor 2009). An essential part of the TASS model is its comprehensive microphysics package, which relies on the accurate computation of microphysical scalar transport. This paper describes an evaluation of the Leonard scheme implemented in the TASS model for transporting microphysical scalars. The scheme is validated against benchmark cases with exact solutions and compared with two other schemes - a Monotone Upstream-centered Scheme for Conservation Laws (MUSCL)-type scheme after van Leer and LeVeque's high-resolution wave propagation method. Finally, a comparison between the schemes is made against an incident of severe tornadic super-cell convection near Del City, Oklahoma.

The exposure history of Jilin and production rates of cosmogenic nuclides

NASA Technical Reports Server (NTRS)

Heusser, G.

1986-01-01

Jilin, the largest known story meteorite, is a very suitable object for studying the systematics of cosmic ray produced nuclides in stony meteorites. Its well established two stage exposure history even permits to gain information about two different irradiation geometries (2pi and 4pi). All stable and long-lived cosmogenic nuclides measured in Jilin so far correlate well with each other. An example is shown where the Al-26 activities are plotted vs. the spallogenic Ne-21 concentration. These records of cosmic-ray interaction in Jilin can be used both to determine the history of the target and to study the nature of production rate profiles. This is unavoidably a bootstrap process, involving studying one with assumption about the other. Production rate equations are presented and discussed.

First chemical separation and identification of Seaborgium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tuerler, A.; Eichler, B.; Jost, D.T.

1997-12-31

The chemical properties of element 106 (Seaborgium, Sg) were successfully studied using the On-line Gas Chromatography Apparatus (OLGA III). After chemical separation of Sg in the form of volatile oxichlorides the nuclides {sup 265}Sg and {sup 266}Sg were unambiguously identified and their half-lives were determined for the first time. The Sg nuclides were produced from the {sup 248}Cm({sup 22}Ne, 4,5n){sup 266,265}Sg reaction at the GSI Darmstadt UNILAC accelerator. Simultaneously, short-lived W nuclides were produced from a small admixture of {sup 152}Gd to the Cm target material. As predicted by relativistic calculations and by extrapolations of chemical properties, it was demonstratedmore » that Sg oxichlorides are indeed less volatile than their lighter homologue W- and Mo-oxichlorides.« less

Spectral identification of a 90Sr source in the presence of masking nuclides using Maximum-Likelihood deconvolution

NASA Astrophysics Data System (ADS)

Neuer, Marcus J.

2013-11-01

A technique for the spectral identification of strontium-90 is shown, utilising a Maximum-Likelihood deconvolution. Different deconvolution approaches are discussed and summarised. Based on the intensity distribution of the beta emission and Geant4 simulations, a combined response matrix is derived, tailored to the β- detection process in sodium iodide detectors. It includes scattering effects and attenuation by applying a base material decomposition extracted from Geant4 simulations with a CAD model for a realistic detector system. Inversion results of measurements show the agreement between deconvolution and reconstruction. A detailed investigation with additional masking sources like 40K, 226Ra and 131I shows that a contamination of strontium can be found in the presence of these nuisance sources. Identification algorithms for strontium are presented based on the derived technique. For the implementation of blind identification, an exemplary masking ratio is calculated.

Assessing the long-term probabilistic volcanic hazard for tephra fallout in Reykjavik, Iceland: a preliminary multi-source analysis

NASA Astrophysics Data System (ADS)

Tonini, Roberto; Barsotti, Sara; Sandri, Laura; Tumi Guðmundsson, Magnús

2015-04-01

Icelandic volcanism is largely dominated by basaltic magma. Nevertheless the presence of glaciers over many Icelandic volcanic systems results in frequent phreatomagmatic eruptions and associated tephra production, making explosive eruptions the most common type of volcanic activity. Jökulhlaups are commonly considered as major volcanic hazard in Iceland for their high frequency and potentially very devastating local impact. Tephra fallout is also frequent and can impact larger areas. It is driven by the wind direction that can change with both altitude and season, making impossible to predict a priori where the tephra will be deposited during the next eruptions. Most of the volcanic activity in Iceland occurs in the central eastern part, over 100 km to the east of the main population centre around the capital Reykjavík. Therefore, the hazard from tephra fallout in Reykjavík is expected to be smaller than for communities settled near the main volcanic systems. However, within the framework of quantitative hazard and risk analyses, less frequent and/or less intense phenomena should not be neglected, since their risk evaluation depends on the effects suffered by the selected target. This is particularly true if the target is highly vulnerable, as large urban areas or important infrastructures. In this work we present the preliminary analysis aiming to perform a Probabilistic Volcanic Hazard Assessment (PVHA) for tephra fallout focused on the target area which includes the municipality of Reykjavík and the Keflavík international airport. This approach reverts the more common perspective where the hazard analysis is focused on the source (the volcanic system) and it follows a multi-source approach: indeed, the idea is to quantify, homogeneously, the hazard due to the main hazardous volcanoes that could pose a tephra fallout threat for the municipality of Reykjavík and the Keflavík airport. PVHA for each volcanic system is calculated independently and the results from all the PVHAs can be combined at the end. This will allow to: 1) possibly add the contribution of new volcanic systems, 2) compare and hierarchically rank the tephra fallout risk among both all the considered volcanoes and, possibly, other kinds of risk, and 3) quantitatively assess the overall tephra fallout hazard over the target area. As practical application, we selected a first subset consisting of the five most hazardous volcanic systems for tephra fallout that could affect the selected target area. These are the ones with the highest number of eruptions in the last 1100 years (Katla, Hekla, Grímsvötn) and the ones located closest to the target area (Reykjanes and Snæfellsjökull). PVHA is computed using the PyBetVH tool (an improvement of the Bayesian Event Tree for Volcanic Hazard -BET_VH- model) and tephra dispersal is modelled by means of VOL-CALPUFF numerical code. Katla volcanic system is used as pilot case study because of its eruptive history and behaviour are well known and documented. We found that some considerations and results derived from the study of Katla could be general and applied to the other considered volcanoes and, more in general, to other Icelandic volcanic systems. The work was financially supported by the European Science Foundation (ESF), in the framework of the Research Networking Programme MeMoVolc.

Characterizing fallout material using Cs and Pu atom ratios in environmental samples from the FDNPP fallout zone

NASA Astrophysics Data System (ADS)

Richards, David; Dunne, James; Martin, Peter; Scott, Tom; Yamashiki, Yosuke; Coath, Chris; Chen, Hart

2017-04-01

Here we report the use of combined of Cs and Pu isotope measurements to investigate the extensive plumes of radioactive fallout from the disaster at Fukishima Daiichi nuclear power plant (FNDPP) in March 2011. Among the aims of our study are improved assessment of the physico-chemical nature and changing distribution of land-based fallout. 135Cs/137Cs and 134Cs/137Cs atom ratios are indicative of conditions that relate to the nuclear fission reactions responsible for producing the respective radiocaesium isotopes, and offer much more in terms of forensic and chronological analysis than monitoring 137Cs alone. We briefly present methods to quantify the atom ratios of Cs and Pu isotopes in soil, lichen and moss samples from FDNPP catchment using mass spectrometry (ThermoTRITON for Cs and ThermoNEPTUNE for Pu). High precision data from Fukushima are presented (e.g decay corrected 135Cs/137Cs atom ratio = 0.384 ± 0.001 (n = 5) for roadside dust from Iitate region), and these are in agreement with prelimary estimates by others. We also confirm results for IAEA-330, a spinach sample collected from Polesskoe, Ukraine and subject to contamination from the Chernobyl accident. In addition to Cs isotopes, we adopt Pu isotopes to add a further dimension to the forensic analysis. We discuss the corrections required for background levels prior to the disaster, possibility for multiple components of fallout and complicating factors associated with remobilisation during the clean-up operation. In parallel with this work on digests and leaches from bulk environmental samples, we are refining methods for particle identification, isolation and characterisation using a complementary sequence of cutting-edge materials and manipulation techniques, including combined electron microscopy, focused ion beam techniques (Dualbeam), nano/micro manipulators and nano-scale imaging x-ray photoelectron spectroscopy (NanoESCA) and microCT.

An estimate by two methods of thyroid absorbed doses due to BRAVO fallout in several Northern Marshall Islands.

PubMed

Musolino, S V; Greenhouse, N A; Hull, A P

1997-10-01

Estimates of the thyroid absorbed doses due to fallout originating from the 1 March 1954 BRAVO thermonuclear test on Bikini Atoll have been made for several inhabited locations in the Northern Marshall Islands. Rongelap, Utirik, Rongerik and Ailinginae Atolls were also inhabited on 1 March 1954, where retrospective thyroid absorbed doses have previously been reconstructed. The current estimates are based primarily on external exposure data, which were recorded shortly after each nuclear test in the Castle Series, and secondarily on soil concentrations of 137Cs in samples collected in 1978 and 1988, along with aerial monitoring done in 1978. The external exposures and 137Cs soil concentrations were representative of the atmospheric transport and deposition patterns of the entire Castle Series tests and show that the BRAVO test was the major contributor to fallout exposure during the Castle series and other test series which were carried out in the Marshall Islands. These data have been used as surrogates for fission product radioiodines and telluriums in order to estimate the range of thyroid absorbed doses that may have occurred throughout the Marshall Islands. Dosimetry based on these two sets of estimates agreed within a factor of 4 at the locations where BRAVO was the dominant contributor to the total exposure and deposition. Both methods indicate that thyroid absorbed doses in the range of 1 Gy (100 rad) may have been incurred in some of the northern locations, whereas the doses at southern locations did not significantly exceed levels comparable to those from worldwide fallout. The results of these estimates indicate that a systematic medical survey for thyroid disease should be conducted, and that a more definitive dose reconstruction should be made for all the populated atolls and islands in the Northern Marshall Islands beyond Rongelap, Utirik, Rongerik and Ailinginae, which were significantly contaminated by BRAVO fallout.

Fallout radionuclide-based techniques for assessing the impact of soil conservation measures on erosion control and soil quality: an overview of the main lessons learnt under an FAO/IAEA Coordinated Research Project.

PubMed

Dercon, G; Mabit, L; Hancock, G; Nguyen, M L; Dornhofer, P; Bacchi, O O S; Benmansour, M; Bernard, C; Froehlich, W; Golosov, V N; Haciyakupoglu, S; Hai, P S; Klik, A; Li, Y; Lobb, D A; Onda, Y; Popa, N; Rafiq, M; Ritchie, J C; Schuller, P; Shakhashiro, A; Wallbrink, P; Walling, D E; Zapata, F; Zhang, X

2012-05-01

This paper summarizes key findings and identifies the main lessons learnt from a 5-year (2002-2008) coordinated research project (CRP) on "Assessing the effectiveness of soil conservation measures for sustainable watershed management and crop production using fallout radionuclides" (D1.50.08), organized and funded by the International Atomic Energy Agency through the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. The project brought together nineteen participants, from Australia, Austria, Brazil, Canada, Chile, China, Japan, Morocco, Pakistan, Poland, Romania, Russian Federation, Turkey, United Kingdom, United States of America and Vietnam, involved in the use of nuclear techniques and, more particularly, fallout radionuclides (FRN) to assess the relative impacts of different soil conservation measures on soil erosion and land productivity. The overall objective of the CRP was to develop improved land use and management strategies for sustainable watershed management through effective soil erosion control practices, by the use of ¹³⁷Cs (half-life of 30.2 years), ²¹⁰Pb(ex) (half-life of 22.3 years) and ⁷Be (half-life of 53.4 days) for measuring soil erosion over several spatial and temporal scales. The environmental conditions under which the different research teams applied the tools based on the use of fallout radionuclides varied considerably--a variety of climates, soils, topographies and land uses. Nevertheless, the achievements of the CRP, as reflected in this overview paper, demonstrate that fallout radionuclide-based techniques are powerful tools to assess soil erosion/deposition at several spatial and temporal scales in a wide range of environments, and offer potential to monitor soil quality. The success of the CRP has stimulated an interest in many IAEA Member States in the use of these methodologies to identify factors and practices that can enhance sustainable agriculture and minimize land degradation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Long-range volcanic ash transport and fallout during the 2008 eruption of Chaiten volcano, Chile

NASA Astrophysics Data System (ADS)

Durant, A. J.; Prata, A. J.; Villarosa, G.; Rose, W. I.; Delmelle, P.; Viramonte, J.

2012-04-01

The May 2008 eruption of Chaitén volcano, Chile, provided a rare opportunity to measure the long-range transport of volcanic emissions and characteristics of a widely-dispersed terrestrial ash deposit. Airborne ash mass, quantified using thermal infrared satellite remote sensing, ranged between 0.2-0.4 Tg during the period 3-7 May 2008. A high level of spatiotemporal correspondence was observed between cloud trajectories and changes in surface reflectivity, which was inferred to indicate ash deposition. The evolution of the deposit was mapped for the first time using satellite-based observations of surface reflectivity. The distal (>80 km) ash deposit was poorly sorted and fine grained, and mean particle size varied very little beyond a distance >300 km. There were 3 consistent particle size subpopulations in fallout at distances >300 km which suggests that aggregation influenced particle settling. Discrete temporal sampling and characterisation of fallout demonstrated contributions from specific eruptive phases. Some evidence for winnowing was identified through comparison of samples collected at the time of deposition to bulk samples collected months after deposition. X-Ray Photoelectron Spectroscopy (XPS) analyses revealed surface enrichments in Ca, Na and Fe and the presence of coatings of mixed Ca-, Na- and Fe-rich salts on ash particles prior to deposition. XPS analyses revealed strong surface Fe enrichments (in contrast to the results from bulk leachate analyses), which indicates that surface analysis techniques should be applied to investigate potential influences on ocean productivity in response to volcanic ash fallout over oceans. Low S:Cl ratios in leachates indicate that the eruption had a low S content, and high Cl:F ratios imply gas-ash interaction within a Cl-rich environment. We estimate that ash fallout had potential to scavenge ~42 % of total S released into the atmosphere prior to deposition.

Transfer factors and effective half-lives of (134)Cs and (137)Cs in different environmental sample types obtained from Northern Finland: case Fukushima accident.

PubMed

Koivurova, Matias; Leppänen, Ari-Pekka; Kallio, Antti

2015-08-01

The Fukushima NPP accident caused a small but detectable cesium fallout in northern Finland, of the order of 1 Bq/m(2). This fallout transferred further to soil, water, flora and fauna. By using modern HPGe detector systems traces of (134)Cs from the Fukushima fallout were observed in various samples of biota. In northern Finland different types of environmental samples such as reindeer meat, berries, fish, lichens and wolf were collected during 2011-2013. The observed (134)Cs concentrations varied from 0.1 Bq/kg to a few Bq/kg. By using the known (134)Cs/(137)Cs ratio observed in Fukushima fallout the increase of the Fukushima accident to the (137)Cs concentrations was found to vary from 0.06 % to 6.9 % depending on the sample type. The aggregated transfer factors (Tag) and effective half-lives (Teff) for (134)Cs and (137)Cs were also determined and then compared with known values found from earlier studies which are calculated based on the fallout from the Chernobyl accident. Generally, the Tag and Teff values determined in this study were found to agree with the values found in the earlier studies. The Teff values were sample-type specific and were found to vary from 0.91 to 2.1 years for (134)Cs and the estimates for (137)Cs ranged between 1.6 and 19 years. Interestingly, the ground lichens had the longest Teff whereas the beard lichen had the shortest. In fauna, highest Tag values were determined for wolf meat ranging between 1.0 and 2.2 m(2)/kg. In flora, the highest Tag values were determined for beard lichens, ranging from 1.9 m(2)/kg to 3.5 m(2)/kg. Copyright © 2015 Elsevier Ltd. All rights reserved.

Stratigraphy, paleoenvironment and emplacement mechanisms of the Koko fissure craters, O'ahu, Hawai'i

NASA Astrophysics Data System (ADS)

Skilling, I. P.; Bluth, J.; Simoneau, E.

2011-12-01

The Koko fissure craters are aligned and nested basanitic tuff cones and rings at the SE corner of O'ahu, Hawai'i. There are no published studies of their stratigraphy, emplacement mechanisms or depositional paleoenvironments. This study focuses on a tuff cone complex (Koko Crater) and a younger adjacent nested tuff ring (Hanauma Bay). A detailed stratigraphy with logged sections for both Koko Crater and the Hanauma Bay craters are presented and discussed. Koko Crater is dominated by wet fallout deposits on steep proximal slopes, commonly resedimented by hot (vesiculated) and cold (unvesiculated) debris flows, slumps and slides, but with an increasing percentage of wet (low temperature) low concentration PDC deposits preserved in the shallowly-dipping flanking apron deposits, and in the uppermost proximal deposits. At least two earlier cone or ring rims are preserved along its southern margin. The deposits of Hanauma Bay overlie the Koko deposits and are dominated by a mix of wet low concentration PDC, wet fallout and synchronous PDC, and fallout deposits in proximal settings, and by low concentration, probably drier, PDC deposits in more distal settings. The Hanauma Bay rings were emplaced before the Koko Crater tephra was consolidated, as steep-sided rills incised into Koko tephra are locally filled with tephra of mixed Koko and Hanauma sources. The onset of Hanauma Bay eruptions is marked by a horizon that is very rich in rounded coral sand clasts. Discontinuous horizons and lenses of coral block fallout are also very common in the Hanauma tephra. Coral sand is absent and coral blocks are much rarer in the Koko tephra. These observations, and probably also the dominance of wet fallout at Koko, imply that Koko was erupted in deeper water than the nearshore coral beach environment of the Hanauma rings. A faster rate of water recharge into the conduit in deeper open water is probably the most important factor in the generation of a cone rather than a ring at this locality.

A Top-Down Pathway to Secondary Eyewall Formation in Simulated Tropical Cyclones

NASA Astrophysics Data System (ADS)

Tyner, Bryce; Zhu, Ping; Zhang, Jun A.; Gopalakrishnan, Sundararaman; Marks, Frank; Tallapragada, Vijay

2018-01-01

Idealized and real-case simulations conducted using the Hurricane Weather Research and Forecasting (HWRF) model demonstrate a "top-down" pathway to secondary eyewall formation (SEF) for tropical cyclones (TCs). For the real-case simulations of Hurricane Rita (2005) and Hurricane Edouard (2014), a comparison to observations reveals the timing and overall characteristics of the simulated SEF appear realistic. An important control of the top-down pathway to SEF is the amount and radial-height distribution of hydrometeors at outer radii. Examination into the simulated hydrometeor particle fall speed distribution reveals that the HWRF operational microphysics scheme is not producing the lightest hydrometeors, which are likely present in observed TCs and are most conducive to being advected from the primary eyewall to the outer rainband region of the TC. Triggering of SEF begins with the fallout of hydrometeors at the outer radii from the TC primary eyewall, where penetrative downdrafts resulting from evaporative cooling of precipitation promote the development of local convection. As the convection-induced radial convergence that is initially located in the midtroposphere extends downward into the boundary layer, it results in the eruption of high entropy air out of the boundary layer. This leads to the rapid development of rainband convection and subsequent SEF via a positive feedback among precipitation, convection, and boundary layer processes.

Scaling in situ cosmogenic nuclide production rates using analytical approximations to atmospheric cosmic-ray fluxes

NASA Astrophysics Data System (ADS)

Lifton, Nathaniel; Sato, Tatsuhiko; Dunai, Tibor J.

2014-01-01

Several models have been proposed for scaling in situ cosmogenic nuclide production rates from the relatively few sites where they have been measured to other sites of interest. Two main types of models are recognized: (1) those based on data from nuclear disintegrations in photographic emulsions combined with various neutron detectors, and (2) those based largely on neutron monitor data. However, stubborn discrepancies between these model types have led to frequent confusion when calculating surface exposure ages from production rates derived from the models. To help resolve these discrepancies and identify the sources of potential biases in each model, we have developed a new scaling model based on analytical approximations to modeled fluxes of the main atmospheric cosmic-ray particles responsible for in situ cosmogenic nuclide production. Both the analytical formulations and the Monte Carlo model fluxes on which they are based agree well with measured atmospheric fluxes of neutrons, protons, and muons, indicating they can serve as a robust estimate of the atmospheric cosmic-ray flux based on first principles. We are also using updated records for quantifying temporal and spatial variability in geomagnetic and solar modulation effects on the fluxes. A key advantage of this new model (herein termed LSD) over previous Monte Carlo models of cosmogenic nuclide production is that it allows for faster estimation of scaling factors based on time-varying geomagnetic and solar inputs. Comparing scaling predictions derived from the LSD model with those of previously published models suggest potential sources of bias in the latter can be largely attributed to two factors: different energy responses of the secondary neutron detectors used in developing the models, and different geomagnetic parameterizations. Given that the LSD model generates flux spectra for each cosmic-ray particle of interest, it is also relatively straightforward to generate nuclide-specific scaling factors based on recently updated neutron and proton excitation functions (probability of nuclide production in a given nuclear reaction as a function of energy) for commonly measured in situ cosmogenic nuclides. Such scaling factors reflect the influence of the energy distribution of the flux folded with the relevant excitation functions. Resulting scaling factors indicate 3He shows the strongest positive deviation from the flux-based scaling, while 14C exhibits a negative deviation. These results are consistent with a recent Monte Carlo-based study using a different cosmic-ray physics code package but the same excitation functions.

A Comparison in the Accuracy of Mapping Nuclear Fallout Patterns Using HPAC, HYSPLIT, DELFIC FPT and an AFIT FORTRAN95 Fallout Deposition ode

DTIC Science & Technology

2011-03-01

Capability (HPAC), HPAC 4.04 On-Line Help. Alexandria VA , April 2005. 13. Draxler, Roland R. and G.D. Hess. Description of the HYSPLIT_4 Modeling...Effects of Nuclear Weapons. Alexandria, VA : The United States Department of Defense and the United States Department of Energy, 1977. 18...77: 437-431 (3 March 1996). 25. Moroz , Brian E., Harold L. Beck, Andre Bouville, and Steven L. Simon. “Predictions of Dispersion and Deposition

Lichens as bioindicators of aerial fallout of heavy metals in Zaria, Nigeria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kapu, M.M.; Ipaye, M.M.; Ega, R.A.I.

1991-09-01

Lichens and other epiphytic cryptogams possess efficient ion-exchange mechanisms which enable many species to accumulate airborne metals and which probably contribute to their tolerating metals at concentrations high enough to cause death to other plant species. A direct relationship between the distribution pattern of lichens and the trace metal content of the surrounding air has been demonstrated. The present study used lichens to assess the aerial fallout of heavy metals from traffic in Zaria, northern Nigeria.

Neutron Scattering Reference

Science.gov Websites

Conversion Factors Periodic Table of the Elements Chart of the Nuclides Map of the Nuclides Computer Index of (Atominstitut der Österreichischen Universitäten) Neutron Activation Table of Elements Neutron Scattering at neutronsources.org. The information contained here in the Neutron Scattering Web has been

Nuclear Data Sheets for A=189

DOE PAGES

Johnson, T. D.; Singh, Balraj

2017-04-26

Evaluated experimental data are presented for 13 known mass 189 nuclides (Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po). Since the 2003Wu02 publication, structure and decay data from 25 new and primary publications have been incorporated in the current work, while adding a new 189Hf nuclide. New data have been added for all nuclides except 189Au and 189Hg. Moreover, several previous datasets were modified for β-decay Q values and conversion coefficients even when no new publications appeared since 2003Wu02. In spite of large amounts of data available for A=189 nuclides, several deficiencies remain, which aremore » pointed out below in the hope that further experimental work may improve our knowledge of structure of these nuclides. For 189Hf and 189Ta, ground-state half-lives, and their decay schemes are unknown. An isomer in 189Ta has recently been established but its decay characteristics are unknown, even though several gamma rays were connected with its decay. No excited states are known in 189W and only one in 189Po. The decay scheme of 189W is known poorly with most gamma rays left as unassigned. The decay schemes of 189Au and 189Pb g.s. suffer from incompleteness, while those for the g.s. and isomer of 189Tl are almost absent. The decay schemes of g.s. and isomer of 189Hg are very complex as apparent from the study by 1996Wo04. Evaluators feel that these two decay schemes could be improved with modern gamma-ray detector arrays. While several isomers are known in many of the A=189 nuclides, there is in general lack of information of level half-lives, thus limiting the knowledge of transition probabilities. High-spin structures, including SD bands in 189Hg and 189Tl, are known in 189Re, 189Ir, 189Pt, 189Au, 189Hg, 189Tl, 189Pb and 189Bi. Single-particle transfer data are available for 189Re, 189Os, and 189Pt; and two-neutron transfer data for 189Ir.« less

Nuclear Data Sheets for A=189

NASA Astrophysics Data System (ADS)

Johnson, T. D.; Singh, Balraj

2017-05-01

Evaluated experimental data are presented for 13 known mass 189 nuclides (Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po). Since the 2003Wu02 publication, structure and decay data from 25 new and primary publications have been incorporated in the current work, while adding a new 189Hf nuclide. New data have been added for all nuclides except 189Au and 189Hg. Moreover, several previous datasets were modified for β-decay Q values and conversion coefficients even when no new publications appeared since 2003Wu02. In spite of large amounts of data available for A=189 nuclides, several deficiencies remain, which are pointed out below in the hope that further experimental work may improve our knowledge of structure of these nuclides. For 189Hf and 189Ta, ground-state half-lives, and their decay schemes are unknown. An isomer in 189Ta has recently been established but its decay characteristics are unknown, even though several gamma rays were connected with its decay. No excited states are known in 189W and only one in 189Po. The decay scheme of 189W is known poorly with most gamma rays left as unassigned. The decay schemes of 189Au and 189Pb g.s. suffer from incompleteness, while those for the g.s. and isomer of 189Tl are almost absent. The decay schemes of g.s. and isomer of 189Hg are very complex as apparent from the study by 1996Wo04. Evaluators feel that these two decay schemes could be improved with modern gamma-ray detector arrays. While several isomers are known in many of the A=189 nuclides, there is in general lack of information of level half-lives, thus limiting the knowledge of transition probabilities. High-spin structures, including SD bands in 189Hg and 189Tl, are known in 189Re, 189Ir, 189Pt, 189Au, 189Hg, 189Tl, 189Pb and 189Bi. Single-particle transfer data are available for 189Re, 189Os, and 189Pt; and two-neutron transfer data for 189Ir.

Nuclear Data Sheets for A=189

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, T. D.; Singh, Balraj

Evaluated experimental data are presented for 13 known mass 189 nuclides (Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po). Since the 2003Wu02 publication, structure and decay data from 25 new and primary publications have been incorporated in the current work, while adding a new 189Hf nuclide. New data have been added for all nuclides except 189Au and 189Hg. Moreover, several previous datasets were modified for β-decay Q values and conversion coefficients even when no new publications appeared since 2003Wu02. In spite of large amounts of data available for A=189 nuclides, several deficiencies remain, which aremore » pointed out below in the hope that further experimental work may improve our knowledge of structure of these nuclides. For 189Hf and 189Ta, ground-state half-lives, and their decay schemes are unknown. An isomer in 189Ta has recently been established but its decay characteristics are unknown, even though several gamma rays were connected with its decay. No excited states are known in 189W and only one in 189Po. The decay scheme of 189W is known poorly with most gamma rays left as unassigned. The decay schemes of 189Au and 189Pb g.s. suffer from incompleteness, while those for the g.s. and isomer of 189Tl are almost absent. The decay schemes of g.s. and isomer of 189Hg are very complex as apparent from the study by 1996Wo04. Evaluators feel that these two decay schemes could be improved with modern gamma-ray detector arrays. While several isomers are known in many of the A=189 nuclides, there is in general lack of information of level half-lives, thus limiting the knowledge of transition probabilities. High-spin structures, including SD bands in 189Hg and 189Tl, are known in 189Re, 189Ir, 189Pt, 189Au, 189Hg, 189Tl, 189Pb and 189Bi. Single-particle transfer data are available for 189Re, 189Os, and 189Pt; and two-neutron transfer data for 189Ir.« less

Nuclear Data Sheets for A = 84

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abriola, Daniel; Bostan, Melih; Erturk, Sefa

The evaluated spectroscopic data are presented for 12 known nuclides of mass 84 (Ga, Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo). Except for the stable nuclides {sup 84}Sr and {sup 84}Kr, extensive new data are available for all the other nuclides since the 1997 evaluation by J.K. Tuli (1997Tu02) of A = 84 nuclides. Many precise Penning-trap mass measurements since AME-2003 for A = 84 nuclides (2009Re03,2008Ha23,2008We10,2007Ke09,2006Ka48,2006De36,2006Ri15) have resulted in improved Q values and separation energies. However, many deficiencies still remain. Some examples are given below. Excited-state data for {sup 84}Ga and {sup 84}As are nonexistent,more » and those for {sup 84}Ge are scarce. The radioactive decay schemes of {sup 84}Ga, {sup 84}Ge, {sup 84}Se, {sup 84}Y (39.5 min), {sup 84}Y (4.6 s), {sup 84}Zr and {sup 84}Nb suffer from incompleteness and that for {sup 84}Mo decay is not known at all. The energy ordering of the two activities (39.5 min and and 4.6 s) of {sup 84}Y is not well established, although, high-spin with tentative spin-parity of (6+) is adopted here as the ground state of {sup 84}Y based on weak arguments. From a conference report published in 2000, it is clear that extensive experiments were done to investigate decays of {sup 84}Zr and {sup 84}Y, but details of these studies never appeared in literature and none were made available to the evaluators when requested from original authors. This evaluation was carried out as part of ENSDF workshop for Nuclear Structure and Decay Data Evaluators, organized and hosted by the 'Horia Hulubei' National Institute for Physics and Nuclear Engineering, Bucharest, Romania during March 30, 2009 - April 3, 2009. Names of the evaluators principally responsible for evaluation of individual nuclides are given under the respective Adopted data sets.« less

Nuclear Data Sheets A = 84

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abriola, D.; Sonzogni, A.; Bostan,M. Erturk,S.

The evaluated spectroscopic data are presented for 12 known nuclides of mass 84 (Ga, Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo). Except for the stable nuclides {sup 84}Sr and {sup 84}Kr, extensive new data are available for all the other nuclides since the 1997 evaluation by J.K. Tuli (1997Tu02) of A = 84 nuclides. Many precise Penning-trap mass measurements since AME-2003 for A = 84 nuclides (2009Re03,2008Ha23,2008We10,2007Ke09,2006Ka48,2006De36,2006Ri15) have resulted in improved Q values and separation energies. However, many deficiencies still remain. Some examples are given below. Excited-state data for {sup 84}Ga and {sup 84}As are nonexistent,more » and those for {sup 84}Ge are scarce. The radioactive decay schemes of {sup 84}Ga, {sup 84}Ge, {sup 84}Se, {sup 84}Y (39.5 min), {sup 84}Y (4.6 s), {sup 84}Zr and {sup 84}Nb suffer from incompleteness and that for {sup 84}Mo decay is not known at all. The energy ordering of the two activities (39.5 min and and 4.6 s) of {sup 84}Y is not well established, although, high-spin with tentative spin-parity of (6+) is adopted here as the ground state of {sup 84}Y based on weak arguments. From a conference report published in 2000, it is clear that extensive experiments were done to investigate decays of {sup 84}Zr and {sup 84}Y, but details of these studies never appeared in literature and none were made available to the evaluators when requested from original authors. This evaluation was carried out as part of ENSDF workshop for Nuclear Structure and Decay Data Evaluators, organized and hosted by the 'Horia Hulubei' National Institute for Physics and Nuclear Engineering, Bucharest, Romania during March 30, 2009 - April 3, 2009. Names of the evaluators principally responsible for evaluation of individual nuclides are given under the respective Adopted data sets.« less

Nuclear data sheets for A=84.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abriola, D.; Bostan, M.; Erturk, S.

The evaluated spectroscopic data are presented for 12 known nuclides of mass 84 (Ga, Ge, As, Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo). Except for the stable nuclides {sup 84}Sr and {sup 84}Kr, extensive new data are available for all the other nuclides since the 1997 evaluation by J.K. Tuli (1997Tu02) of A = 84 nuclides. Many precise Penning-trap mass measurements since AME-2003 for A = 84 nuclides (2009Re03,2008Ha23,2008We10,2007Ke09,2006Ka48,2006De36,2006Ri15) have resulted in improved Q values and separation energies. However, many deficiencies still remain. Some examples are given below. Excited-state data for {sup 84}Ga and {sup 84}As are nonexistent,more » and those for {sup 84}Ge are scarce. The radioactive decay schemes of {sup 84}Ga, {sup 84}Ge, {sup 84}Se, {sup 84}Y (39.5 min), {sup 84}Y (4.6 s), {sup 84}Zr and {sup 84}Nb suffer from incompleteness and that for {sup 84}Mo decay is not known at all. The energy ordering of the two activities (39.5 min and 4.6 s) of {sup 84}Y is not well established, although, high-spin with tentative spin-parity of (6+) is adopted here as the ground state of {sup 84}Y based on weak arguments. From a conference report published in 2000, it is clear that extensive experiments were done to investigate decays of {sup 84}Zr and {sup 84}Y, but details of these studies never appeared in literature and none were made available to the evaluators when requested from original authors. This evaluation was carried out as part of ENSDF workshop for Nuclear Structure and Decay Data Evaluators, organized and hosted by the 'Horia Hulubei' National Institute for Physics and Nuclear Engineering, Bucharest, Romania during March 30, 2009 - April 3, 2009. Names of the evaluators principally responsible for evaluation of individual nuclides are given under the respective Adopted data sets.« less

Decay heat power of spent nuclear fuel of power reactors with high burnup at long-term storage

NASA Astrophysics Data System (ADS)

Ternovykh, Mikhail; Tikhomirov, Georgy; Saldikov, Ivan; Gerasimov, Alexander

2017-09-01

Decay heat power of actinides and fission products from spent nuclear fuel of power VVER-1000 type reactors at long-term storage is calculated. Two modes of storage are considered: mode in which single portion of actinides or fission products is loaded in storage facility, and mode in which actinides or fission products from spent fuel of one VVER reactor are added every year in storage facility during 30 years and then accumulated nuclides are stored without addition new nuclides. Two values of fuel burnup 40 and 70 MW·d/kg are considered for the mode of storage of single fuel unloading. For the mode of accumulation of spent fuel with subsequent storage, one value of burnup of 70 MW·d/kg is considered. Very long time of storage 105 years accepted in calculations allows to simulate final geological disposal of radioactive wastes. Heat power of fission products decreases quickly after 50-100 years of storage. The power of actinides decreases very slow. In passing from 40 to 70 MW·d/kg, power of actinides increases due to accumulation of higher fraction of 244Cm. These data are important in the back end of fuel cycle when improved cooling system of the storage facility will be required along with stronger radiation protection during storage, transportation and processing.

APSTNG: neutron interrogation for detection of explosives, drugs, and nuclear and chemical warfare materials

NASA Astrophysics Data System (ADS)

Rhodes, Edgar A.; Peters, Charles W.

1993-02-01

A recently developed neutron diagnostic probe system has the potential to satisfy a significant number of van-mobile and fixed-portal requirements for nondestructive detection, including monitoring of contraband explosives, drugs, and weapon materials, and treaty verification of sealed munitions. The probe is based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14- MeV neutrons generated from the deuterium-tritium reaction and that detects the alpha-particle associated with each neutron. Gamma-ray spectra of resulting neutron reactions identify nuclides associated with all major chemicals in explosives, drugs, and chemical warfare agents, as well as many pollutants and fissile and fertile special nuclear material. Flight times determined from detection times of the gamma-rays and alpha-particles yield a separate coarse tomographic image of each identified nuclide. The APSTNG also forms the basis for a compact fast-neutron transmission imaging system that can be used along with or instead of the emission imaging system. Proof-of-concept experiments have been performed under laboratory conditions for simulated nuclear and chemical warfare munitions and for explosives and drugs. The small and relatively inexpensive APSTNG exhibits high reliability and can be quickly replaced. Surveillance systems based on APSTNG technology can avoid the large physical size, high capital and operating expenses, and reliability problems associated with complex accelerators.

Age-erosion constraints on an Early Pleistocene paleosol in Yukon, Canada, with profiles of 10Be and 26Al: Evidence for a significant loess cover effect on cosmogenic nuclide production rates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hidy, Alan J.; Gosse, John C.; Sanborn, Paul

We report that Wounded Moose type paleosols developed on remnant deposits of Late Pliocene to Early Pleistocene [pre-Reid] Cordilleran Ice Sheet [CIS] glaciations in central Yukon, Canada. It is an important regional soil-geomorphic marker at the boundary between early CIS advances and the non-glaciated regions of Yukon and Alaska. Yet, at present, its age is poorly constrained between the Reid [0.2 Ma] and earliest [2.84 Ma] CIS advances. Here, we apply depth profiles of in situ-produced cosmogenic 26Al and 10Be to obtain both a minimum exposure age [1.12 +0.44/ -0.36 Ma, 2σ] and maximum erosion rate [1.1 +0.9/ -0.5 mmore » Myr -1] for the Wounded Moose paleosol. Here, our results show that this soil formed under exceptionally stable conditions [max erosion rate similar to polar bedrock erosion rates] and that it pre-dates the emergence of the 100 ka [eccentricity] climate cycle. Contrasting our results from single- and joint-nuclide depth profile models reveals a significant discrepancy between calculated and effective 10Be and 26Al production rates [40–65% of expected values]. We interpret this discrepancy as the result of intermittent loess cover—with a time-averaged depth between 60 and 110 cm—which significantly reduced apparent exposure ages obtained from the single–nuclide model. The observation of such a significant loess-cover effect on cosmogenic nuclide production has implications for exposure dating in glacial and periglacial environments; a multi-nuclide sampling strategy is required to quantify this effect.« less

Age-erosion constraints on an Early Pleistocene paleosol in Yukon, Canada, with profiles of 10Be and 26Al: Evidence for a significant loess cover effect on cosmogenic nuclide production rates

DOE PAGES

Hidy, Alan J.; Gosse, John C.; Sanborn, Paul; ...

2018-02-16

We report that Wounded Moose type paleosols developed on remnant deposits of Late Pliocene to Early Pleistocene [pre-Reid] Cordilleran Ice Sheet [CIS] glaciations in central Yukon, Canada. It is an important regional soil-geomorphic marker at the boundary between early CIS advances and the non-glaciated regions of Yukon and Alaska. Yet, at present, its age is poorly constrained between the Reid [0.2 Ma] and earliest [2.84 Ma] CIS advances. Here, we apply depth profiles of in situ-produced cosmogenic 26Al and 10Be to obtain both a minimum exposure age [1.12 +0.44/ -0.36 Ma, 2σ] and maximum erosion rate [1.1 +0.9/ -0.5 mmore » Myr -1] for the Wounded Moose paleosol. Here, our results show that this soil formed under exceptionally stable conditions [max erosion rate similar to polar bedrock erosion rates] and that it pre-dates the emergence of the 100 ka [eccentricity] climate cycle. Contrasting our results from single- and joint-nuclide depth profile models reveals a significant discrepancy between calculated and effective 10Be and 26Al production rates [40–65% of expected values]. We interpret this discrepancy as the result of intermittent loess cover—with a time-averaged depth between 60 and 110 cm—which significantly reduced apparent exposure ages obtained from the single–nuclide model. The observation of such a significant loess-cover effect on cosmogenic nuclide production has implications for exposure dating in glacial and periglacial environments; a multi-nuclide sampling strategy is required to quantify this effect.« less

Isotopic Pu, Am and Cm signatures in environmental samples contaminated by the Fukushima Dai-ichi Nuclear Power Plant accident.

PubMed

Yamamoto, M; Sakaguchi, A; Ochiai, S; Takada, T; Hamataka, K; Murakami, T; Nagao, S

2014-06-01

Dust samples from the sides of roads (black substances) have been collected together with litter and soil samples at more than 100 sites contaminated heavily in the 20-km exclusion zones around Fukushima Dai-ichi Nuclear Power Plant (FDNPP) (Minamisoma City, and Namie, Futaba and Okuma Towns), in Iitate Village located from 25 to 45 km northwest of the plant and in southern areas from the plant. Isotopes of Pu, Am and Cm have been measured in the samples to evaluate their total releases into the environment from the FDNPP and to get the isotopic compositions among these nuclides. For black substances and litter samples, in addition to Pu isotopes, (241)Am, (242)Cm and (243,244)Cm were determined for most of samples examined, while for soil samples, only Pu isotopes were determined. The results provided a coherent data set on (239,240)Pu inventories and isotopic composition among these transuranic nuclides. When these activity ratios were compared with those for fuel core inventories in the FDNPP accident estimated by a group at JAEA, except (239,240)Pu/(137)Cs activity ratios, fairly good agreements were found, indicating that transuranic nuclides, probably in the forms of fine particles, were released into the environment without their large fractionations. The obtained data may lead to more accurate information about the on-site situation (e.g., burn-up, conditions of fuel during the release phase, etc.), which would be difficult to get otherwise, and more detailed information on the dispersion and deposition processes of transuranic nuclides and the behavior of these nuclides in the environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fallout 137Cs in reindeer herders in Arctic Norway.

PubMed

Skuterud, Lavrans; Thørring, Håvard

2015-03-03

Reindeer herders in the Arctic were among the most heavily exposed populations to the global fallout from nuclear weapons testing in the 1950s and 1960s, due to high transfer of radionuclides in the lichens-reindeer-human food chain. Annual studies of (137)Cs in reindeer herders in Kautokeino, Norway, were initiated in 1965 to monitor radiation doses and follow environmental (137)Cs behavior. The (137)Cs concentrations declined from the peak in 1965 with effective half-times of 6-8 years, only interrupted by a temporary doubling in levels from 1986 to 1987 due to the Chernobyl fallout. During the period of 1950-2010 an average herder received an integrated effective dose from incorporated (137)Cs of about 18 mSv. This dose represents an insignificant increase in the risk for developing cancer. Health studies even show a significantly lower cancer incidence among Sámis and reindeer herders in northern Norway compared to other populations in the same area.

A two step method to treat variable winds in fallout smearing codes. Master's thesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hopkins, A.T.

1982-03-01

A method was developed to treat non-constant winds in fallout smearing codes. The method consists of two steps: (1) location of the curved hotline (2) determination of the off-hotline activity. To locate the curved hotline, the method begins with an initial cloud of 20 discretely-sized pancake clouds, located at altitudes determined by weapon yield. Next, the particles are tracked through a 300 layer atmosphere, translating with different winds in each layer. The connection of the 20 particles' impact points is the fallout hotline. The hotline location was found to be independent of the assumed particle size distribution in the stabilizedmore » cloud. The off-hotline activity distribution is represented as a two-dimensional gaussian function, centered on the curved hotline. Hotline locator model results were compared to numerical calculations of hypothetical 100 kt burst and to the actual hotline produced by the Castle-Bravo 15 Mt nuclear test.« less

Concentration of (137)Cs in soil across Nebraska.

PubMed

Weesner, Alexandra Palensky; Fairchild, Robert W

2008-06-01

Atmospheric nuclear weapons testing from 1945 through 1980 produced radioactive fallout that was transported by stratospheric winds and deposited unevenly around the world. The accident at Chernobyl in 1986 also contributed to the fallout in some locations. The (137)Cs activity concentration from fallout has been measured as a function of depth in soil samples from five different locations across Nebraska. Soil samples 2-cm thick down to a depth of 30 cm were collected in Brown, Dawes, Lancaster, Red Willow, and Thurston Counties. Samples taken from each of the sites were dried, sieved, and counted using an HPGe gamma spectroscopy system to measure the activity concentration of (137)Cs at each depth in the soil. Activity concentrations as high as 216 Bq kg(-1) were measured in the samples. Dry soil bulk densities were calculated for each site based on soil type and used to calculate the area density of deposition. Area deposition densities up to 13,100 Bq m(-2) were measured, consistent with published estimates.

Nuclear Data Sheets for A = 222

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, S.; Tuli, J.; Jain,A.K.

The ENSDF evaluation for A=222 mass chain (1996El01) has been updated on the basis of the experimental results, since September 1995 (literature cutoff date in 1996El01), from various reaction and decay studies for all nuclides in A=222 mass chain (Z=84 to 92). A new nuclide ({sup 222}Po) has since been observed. In addition, new measurements have been reported in Rn, Th and Ra nuclides. The results obtained from various theoretical studies are given as comments. The updated level and decay schemes, and experimental decay and reaction data on which they are based, are summarized and presented for all the nuclidesmore » with mass number A=222. The adopted values of level energies, level spins and parities are given, and {gamma}-ray energies, intensities, as well as other nuclear properties are presented.« less

Solubility testing of actinides on breathing-zone and area air samples

NASA Astrophysics Data System (ADS)

Metzger, Robert Lawrence

The solubility of inhaled radionuclides in the human lung is an important characteristic of the compounds needed to perform internal dosimetry assessments for exposed workers. A solubility testing method for uranium and several common actinides has been developed with sufficient sensitivity to allow profiles to be determined from routine breathing zone and area air samples in the workplace. Air samples are covered with a clean filter to form a filter-sample-filter sandwich which is immersed in an extracellular lung serum simulant solution. The sample is moved to a fresh beaker of the lung fluid simulant each day for one week, and then weekly until the end of the 28 day test period. The soak solutions are wet ashed with nitric acid and hydrogen peroxide to destroy the organic components of the lung simulant solution prior to extraction of the nuclides of interest directly into an extractive scintillator for subsequent counting on a Photon-Electron Rejecting Alpha Liquid Scintillation (PERALSsp°ler ) spectrometer. Solvent extraction methods utilizing the extractive scintillators have been developed for the isotopes of uranium, plutonium, and curium. The procedures normally produce an isotopic recovery greater than 95% and have been used to develop solubility profiles from air samples with 40 pCi or less of Usb3Osb8. This makes it possible to characterize solubility profiles in every section of operating facilities where airborne nuclides are found using common breathing zone air samples. The new method was evaluated by analyzing uranium compounds from two uranium mills whose product had been previously analyzed by in vitro solubility testing in the laboratory and in vivo solubility testing in rodents. The new technique compared well with the in vivo rodent solubility profiles. The method was then used to evaluate the solubility profiles in all process sections of an operating in situ uranium plant using breathing zone and area air samples collected during routine plant operations. The solubility profiles developed from this work showed excellent agreement with the results of the worker urine bioassay program at the plant and identified a significant error in existing internal dose assessments at this facility.

Assessment of the trend of degradation of arable soils on the basis of data on the rate of stratozem development obtained with the use of 137Cs as a chronomarker

NASA Astrophysics Data System (ADS)

Golosov, V. N.; Ivanova, N. N.; Gusarov, A. V.; Sharifullin, A. G.

2017-10-01

A new approach for determining the trend of changes in the rate of degradation of arable soils is suggested. It is based on the assessment of volumes of soil material eroded from arable fields and accumulated on the bottoms of first-order valleys during two time intervals: 1954(1963)-1986 and 1986-2015. For dating of this material, 137Cs of global fallout and Chernobyl fallout are used. This approach in combination with a detailed morphometric characterization of the valley bottoms, the pathways of sediment transport from the fields, and the morphology and composition of the sediments accumulated on the bottoms makes it possible to give reliable estimates of the volumes of soil loss from tilled slopes. The benchmarks of 1963 and 1986 are related to maximum 137Cs fallout during nuclear bomb testing and immediately after the Chernobyl accident. As an example, the rates of formation of stratozems (stratified aggraded soils formed due to accumulation of eroded sediments) within the first-order catchment of the Veduga River basin (Voronezh oblast, Russia) are analyzed. The results of the study indicate that the mean annual rate of soil loss from arable fields of the catchment in 1986-2015 was at least two times lower than that in the preceding period from 1954 (the beginning of the global fallout) to 1986 (the Chernobyl accident).

The effect of wind and eruption source parameter variations on tephra fallout hazard assessment: an example from Vesuvio (Italy)

NASA Astrophysics Data System (ADS)

Macedonio, Giovanni; Costa, Antonio; Scollo, Simona; Neri, Augusto

2015-04-01

Uncertainty in the tephra fallout hazard assessment may depend on different meteorological datasets and eruptive source parameters used in the modelling. We present a statistical study to analyze this uncertainty in the case of a sub-Plinian eruption of Vesuvius of VEI = 4, column height of 18 km and total erupted mass of 5 × 1011 kg. The hazard assessment for tephra fallout is performed using the advection-diffusion model Hazmap. Firstly, we analyze statistically different meteorological datasets: i) from the daily atmospheric soundings of the stations located in Brindisi (Italy) between 1962 and 1976 and between 1996 and 2012, and in Pratica di Mare (Rome, Italy) between 1996 and 2012; ii) from numerical weather prediction models of the National Oceanic and Atmospheric Administration and of the European Centre for Medium-Range Weather Forecasts. Furthermore, we modify the total mass, the total grain-size distribution, the eruption column height, and the diffusion coefficient. Then, we quantify the impact that different datasets and model input parameters have on the probability maps. Results shows that the parameter that mostly affects the tephra fallout probability maps, keeping constant the total mass, is the particle terminal settling velocity, which is a function of the total grain-size distribution, particle density and shape. Differently, the evaluation of the hazard assessment weakly depends on the use of different meteorological datasets, column height and diffusion coefficient.

Sources of the transuranic elements plutonium and neptunium in arctic marine sediments.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooper, L. W.; Kelley, J. M.; Bond, L. A.

2000-01-01

We report here thermal ionization mass spectrometry measurements of {sup 239}Pu, {sup 240}Pu, {sup 241}Pu, {sup 242}Pu, and {sup 237}Np isolated from oceanic, estuarine, and riverine sediments from the Arctic Ocean Basin. {sup 238}Pu/{sup 239+240}Pu activity ratios are also reported for alpha spectrometric analyses undertaken on a subset of these samples. Our results indicate that the Pu in sediments on the Alaskan shelf and slope, as well as that in the deep basins (Amerasian and Eurasian) of the Arctic Ocean, has its origin in stratospheric and tropospheric fallout. Sediments from the Ob and Yenisei Rivers show isotopic Pu signatures thatmore » are distinctly different from those of northern-hemisphere stratospheric fallout and indicate the presence of weapons-grade Pu originating from nuclear fuel reprocessing wastes generated at Russian facilities within these river catchments. Consequently, sediments of the Eurasian Arctic Ocean, particularly those in the Barents and Kara Seas, probably contain a mixture of Pu from stratospheric fallout, tropospheric fallout, and fuel-reprocessing wastes of riverine origin. In particular, the {sup 241}Pu/{sup 239}Pu ratios observed in these sediments are inconsistent with significant contributions of Pu to the arctic sediments studied from western European reprocessing facilities, principally Sellafield in the UK. Several other potential sources of Pu to arctic sediments can also be excluded as significant based upon the transuranic isotope ratios presented.« less

Migration of fallout radiocaesium in a grassland soil from 1986 to 2001. Part I: activity-depth profiles of (134)Cs and (137)Cs.

PubMed

Schimmack, W; Schultz, W

2006-09-15

The temporal changes of the vertical distribution of (134)Cs (deposited by the Chernobyl fallout in 1986) and (137)Cs (deposited by the Chernobyl and the global fallout) in the soil were investigated at an undisturbed Bavarian grassland site in Germany. At ten sampling dates between 1986 and 2001, the activity density of (134)Cs and (137)Cs was determined in various soil layers down to 80 cm depth. In 2001, the small-scale spatial variability of the radiocaesium activity was determined by sampling five plots within 10 m(2) (coefficient of variation about 20% for the upper soil layers). Between 1987 and 1990, substantial changes of the activity-depth profiles were observed. The percentage depth distributions of (134)Cs and (137)Cs were rather similar. The 50%-depth of the accumulated activity increased from 2.4 cm in 1988 to 5.3 cm in 2001 for (134)Cs and from 2.7 to 5.8 cm for (137)Cs. This indicates that at the study site the migration data of Chernobyl-derived (137)Cs can be estimated by those of total (137)Cs. In the second part of this study, the activity-depth profiles will be evaluated by the convection-dispersion model [Schimmack, W, Feria Márquez, F. Migration of fallout radiocaesium in a grassland soil from 1986 to 2001. Part II: Evaluation of the activity-depth profiles by transport models. Sci Total Environ 2006-this issue].

Fukushima fallout at Milano, Italy.

PubMed

Ioannidou, Alexandra; Manenti, Simone; Gini, Luigi; Groppi, Flavia

2012-12-01

The radionuclides (131)I, (137)Cs and (134)Cs were observed in the Milano region (45°) of Italy early after the nuclear accident in Fukushima, Japan. Increased atmospheric radioactivity was observed on an air filter taken on 30 March 2011, while the maximum activity of 467 μBq m(-3) for (131)I was recorded at April 3-4, 2011. The first evidence of Fukushima fallout was confirmed with (131)I and (137)Cs measured in precipitation at two sampling sites at Milano on 28 March, 2011, with the concentrations of (131)I and (137)Cs in the rainwater equal to 0.89 Bq L(-1) and 0.12 Bq L(-1), respectively. A sample of dry deposition that was collected 9 days after the first rainfall event of 27-28 March, 2011 showed that the dry deposition was more effective in the case of (137)Cs than it was for (131)I, probably because iodine was mainly in gaseous form whereas caesium was rapidly bound to aerosols and thus highly subject to dry deposition. The relatively high observed values of (137)Cs in grass, soil and fresh goat and cow milk samples were probably from Chernobyl fallout and global fallout from past nuclear tests rather than from the Fukushima accident. Finally, a dose assessment for the region of investigation showed clearly that the detected activities in all environmental samples were very far below levels of concern. Copyright © 2012 Elsevier Ltd. All rights reserved.

Nuclear Data Sheets for A=150

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basu, S.K.; Sonzogni, A.A.

The experimental results from the various reaction and decay studies leading to nuclides in the A=150 mass chain have been reviewed. These data are summarized and presented, together with the adopted level schemes and properties, for the nuclides from Cs(Z=55) through Lu(Z=71). This evaluation replaces the previous evaluation by E. der Mateosian and J. K. Tuli (1995De28), which appeared in Nuclear Data Sheets 75, 827 (1995)

Nuclear Data Sheets for A=150

NASA Astrophysics Data System (ADS)

Basu, S. K.; Sonzogni, A. A.

2013-04-01

The experimental results from the various reaction and decay studies leading to nuclides in the A=150 mass chain have been reviewed. These data are summarized and presented, together with the adopted level schemes and properties, for the nuclides from Cs(Z=55) through Lu(Z=71). This evaluation replaces the previous evaluation by E. der Mateosian and J. K. Tuli (1995De28), which appeared in Nuclear Data Sheets 75, 827 (1995).

Sensitivity Analysis of Nuclide Importance to One-Group Neutron Cross Sections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sekimoto, Hiroshi; Nemoto, Atsushi; Yoshimura, Yoshikane

The importance of nuclides is useful when investigating nuclide characteristics in a given neutron spectrum. However, it is derived using one-group microscopic cross sections, which may contain large errors or uncertainties. The sensitivity coefficient shows the effect of these errors or uncertainties on the importance.The equations for calculating sensitivity coefficients of importance to one-group nuclear constants are derived using the perturbation method. Numerical values are also evaluated for some important cases for fast and thermal reactor systems.Many characteristics of the sensitivity coefficients are derived from the derived equations and numerical results. The matrix of sensitivity coefficients seems diagonally dominant. However,more » it is not always satisfied in a detailed structure. The detailed structure of the matrix and the characteristics of coefficients are given.By using the obtained sensitivity coefficients, some demonstration calculations have been performed. The effects of error and uncertainty of nuclear data and of the change of one-group cross-section input caused by fuel design changes through the neutron spectrum are investigated. These calculations show that the sensitivity coefficient is useful when evaluating error or uncertainty of nuclide importance caused by the cross-section data error or uncertainty and when checking effectiveness of fuel cell or core design change for improving neutron economy.« less

PROJECTED LIFETIME CANCER RISKS FROM EXPOSURE TO REGIONAL RADIOACTIVE FALLOUT IN THE MARSHALL ISLANDS

PubMed Central

Land, Charles E.; Bouville, Andre; Apostoaei, Iulian; Simon, Steven L.

2013-01-01

Radioactive fallout from nuclear test detonations during 1946–1958 at Bikini and Enewetak atolls in the Marshall Islands (MI) exposed populations living elsewhere in the archipelago. A comprehensive analysis, presented in seven companion papers, has produced estimates of tissue-specific radiation absorbed dose to MI residents at all historically inhabited atolls from internal (ingested) and external radioactive components of fallout, by calendar year, and by age of the population at time of exposure. The present report deals, for the first time, with the implications of these doses on cancer risk among exposed members of the MI population. Radiation doses differed by geographic location and year of birth, and radiation-related cancer risk depends upon age at exposure and age at observation for risk. Using dose-response models based on committee reports published by the National Research Council and the National Institutes of Health, we project that, during the lifetimes of members of the MI population potentially exposed to ionizing radiation from weapons test fallout deposited during the testing period (1948–1958) and from residual radioactive sources during the subsequent 12 years (1959–1970), perhaps 1.6% (with 90% uncertainty range 0.4% and 3.4%) of all cancers might be attributable to fallout-related radiation exposures. The projected proportion of cancers attributable to radiation from fallout from all nuclear tests conducted in the Marshall Islands is 55% (28%–69%) among 82 persons exposed in 1954 on Rongelap and Ailinginae, 10% (2%–22%) for 157 persons exposed on Utrik, and 2% (0.5%–5%) and 1% (0.2%–2%), respectively, for the much larger populations exposed in mid-latitude locations including Kwajalein and in southern locations including Majuro. By cancer type, point estimates of attributable risk varied by location, between 12% and 95% for thyroid cancer, between 2% and 78% for leukemia, and between 1% and 55% for all cancers combined. The largest projected risks pertain to the Rongelap Island community and the lowest risks pertain to the populations resident on the southern-most atolls. While the projected cancer risks are smaller than those estimated by the National Cancer Institute in simplistic analyses conducted in 2004, these estimates of cancer risk are the best available as they are based on the most detailed dose reconstruction to date and comprehensively include populations at all locations and dose contributions from all nuclear tests. PMID:20622551

Projected lifetime cancer risks from exposure to regional radioactive fallout in the Marshall Islands.

PubMed

Land, Charles E; Bouville, André; Apostoaei, Iulian; Simon, Steven L

2010-08-01

Radioactive fallout from nuclear test detonations during 1946-1958 at Bikini and Enewetak Atolls in the Marshall Islands (MI) exposed populations living elsewhere in the MI archipelago. A comprehensive analysis, presented in seven companion papers, has produced estimates of tissue-specific radiation absorbed dose to MI residents at all historically inhabited atolls from internal (ingested) and external irradiation resulting from exposure to radioactive fallout, by calendar year, and by age of the population at time of exposure. The present report deals, for the first time, with the implications of these doses for cancer risk among exposed members of the MI population. Radiation doses differed by geographic location and year of birth, and radiation-related cancer risk depends upon age at exposure and age at observation for risk. Using dose-response models based on committee reports published by the National Research Council and the National Institutes of Health, we project that, during the lifetimes of members of the MI population potentially exposed to ionizing radiation from weapons test fallout deposited during the testing period (1948-1958) and from residual radioactive sources during the subsequent 12 y (1959-1970), perhaps 1.6% (with 90% uncertainty range 0.4% to 3.4%) of all cancers might be attributable to fallout-related radiation exposures. By sub-population, the projected proportion of cancers attributable to radiation from fallout from all nuclear tests conducted in the Marshall Islands is 55% (28% to 69%) among 82 persons exposed in 1954 on Rongelap and Ailinginae, 10% (2.4% to 22%) for 157 persons exposed on Utrik, and 2.2% (0.5% to 4.8%) and 0.8% (0.2% to 1.8%), respectively, for the much larger populations exposed in mid-latitude locations including Kwajalein and in southern locations including Majuro. By cancer type, point estimates of attributable risk varied, by location, between 12% and 95% for thyroid cancer, between 2% and 78% for leukemia, and between 0.8% and 55% for all cancers combined. The largest projected risks pertain to the Rongelap Island community and the lowest risks pertain to the populations resident on the southern-most atolls. While the projected cancer risks are smaller than those estimated by the National Cancer Institute in a more simplistic analysis conducted in 2004, these estimates of cancer risk are the best available as they are based on the most detailed dose reconstruction to date and comprehensively include populations at all locations and dose contributions from all nuclear tests.

The Tephra Layer From the Plinian Eruption in ™r‘faj”kull 1362, Southeast Iceland

NASA Astrophysics Data System (ADS)

Selbekk, R. S.

2002-12-01

Pyroclastic fallout from the 1362 eruption of ™r‘faj”kull forms one of the volcanic marker horizons of the North Atlantic. This contribution reports the mineralogical and geochemical characteristics of the ™r‘faj”kull 1362 fallout and its grain-size distribution. A non-rifting 120 km long volcanic lineament some 50 km east of the Eastern Rift-Zone of Iceland is defined by transitional and alkalic volcanic rocks resting unconformably on late Tertiary strata. ™r‘faj”kull which forms the southern termination of this off-rift liniment is an ice-covered stratovolcano (2200 masl) composed mostly of subglacially formed hyaloclastite ranging from basalts to rhyolites. The two historical (1100 yrs) eruptions of ™r‘faj”kull include a small explosive eruption in 1727 and a large devastating Plinian eruption associated with major lahars and a caldera collapse in 1362. Between 1 and 2 km3 dense rock equivalent or 5-10 km3 of rhyolitic pumice was erupted and the fallout was mainly towards ESE. Tentative modelling of the PT-conditions of the magma formation, based on glass/mineral equilibria, indicates that the source was a near-eutectic melt in equilibrium with fayalite, hedenbergite, oligoclase and hematite at some 0.2 GPa pressure. A profile through the fallout was sampled at elevation of about 1100 masl on the SE flank of the volcano. A deposit of 1.8 m thickness was collected in 14 units for examination of composition, mineralogy and grain-size distribution during the eruption. In the profile the fallout is fine grained vesicular glass (1-3% minerals, 3% lithic fragments) with bubble wall thickness in the low micron range. The high and even vesiculation of the glass indicates fast magma ascent and explains the extreme mechanical fragmentation within the eruptive column, yielding between 50 and 80 wt% of less than 0.25 mm grain size. A reconstruction of the Plinian phase, based on grain-size analysis and abundance of lithic fragments, reveals that the eruption proceeded in three successive phases. An initial explosion produced phreatomagmatic debris associated with up to 35% of lithic fragments. In distal facies of the fallout, the initial phase is recognised as pale brownish base of the otherwise white glassy layer. The material ejection proceeded in two largely similar phases. These phases are separated only by a transition in grain size distribution indicating a temporary lowering in the effusion rate.

In-vitro analysis of the dissolution kinetics and systemic availability of plutonium ingested in the form of 'hot' particles from the Semipalatinsk NTS.

PubMed

Conway, M; León Vintró, L; Mitchell, P I; García-Tenorio, R; Jimenez-Ramos, M C; Burkitbayev, M; Priest, N D

2009-05-01

In-vitro leaching of radioactive 'hot' particles isolated from soils sampled at the Semipalatinsk Nuclear Test Site has been carried out in order to evaluate the fraction of plutonium activity released into simulated human stomach and small intestine fluids during digestion. Characterisation of the particles (10-100 Bq(239,240)Pu) and investigation of their dissolution kinetics in simulated fluids has been accomplished using a combination of high-resolution alpha-spectrometry, gamma-spectrometry and liquid scintillation counting. The results of these analyses indicate that plutonium transfer across the human gut following the ingestion of 'hot' particles can be up to two orders of magnitude lower than that expected for plutonium in a more soluble form, and show that for areas affected by local fallout, use of published ingestion dose coefficients, together with bulk radionuclide concentrations in soil, may lead to a considerable overestimation of systemic uptake via the ingestion pathway.

Non-Destructive Analysis of Natural Uranium Pellet

NASA Astrophysics Data System (ADS)

Wigley, Samantha; Glennon, Kevin; Kitcher, Evans; Folden, Cody

2017-09-01

As part of ongoing nuclear forensics research, samples of natUO2 have been irradiated in a thermal neutron spectrum at the University of Missouri Research Reactor (MURR) with the goal of simulating a pressurized heavy water reactor. Non-destructive gamma ray analysis has been performed on the samples to assay various nuclides in order to determine the burnup and time since irradiation. The quantity of 137Cs was used to determine the burnup directly, and a maximum likelihood method has been used to estimate both the burnup and the time since irradiation. This poster will discuss the most recent results of these analyses. National Science Foundation (PHY-1659847), Department of Energy (DE-FG02-93ER40773).

ASSESSING INTERNAL CONTAMINATION AFTER THE DETONATION OF A RADIOLOGICAL DISPERSION DEVICE USING A 2×2-INCH SODIUM IODIDE DETECTOR

PubMed Central

Dewji, S.; Hertel, N.; Ansari, A.

2017-01-01

The detonation of a radiological dispersion device may result in a situation where individuals inhale radioactive materials and require rapid assessment of internal contamination. The feasibility of using a 2×2-inch sodium-iodide detector to determine the committed effective dose to an individual following acute inhalation of gamma-emitting radionuclides was investigated. Experimental configurations of point sources with a polymethyl methacrylate slab phantom were used to validate Monte Carlo simulations. The validated detector model was used to simulate the responses for four detector positions on six different anthropomorphic phantoms. The nuclides examined included 241Am, 60Co, 137Cs, 131I and 192Ir. Biokinetic modelling was employed to determine the distributed activity in the body as a function of post-inhalation time. The simulation and biokinetic data were used to determine time-dependent count-rate values at optimal detector locations on the body for each radionuclide corresponding to a target committed effective dose (E50) value of 250 mSv. PMID:23436621

Compilation of Local Fallout Data from Test Detonations 1945-1962 Extracted from DASA 1251. Volume I. Continental U.S. Tests

DTIC Science & Technology

1979-05-01

fallout patterns by "dot-dash" lines. The time lines are intended to give only a rough average arrival time in hours as estimated from the wind reports and...by interpolation between the H-lI and H+11 hour values. 4. The surface air pressure was 13.10 psi, the temperature -2.O°C and the relative humidity...surface air pressure was 13.04 psi, the temperature -2.8 0 C, and the relative humidity 87%. 17 i’ 17 I

Operation Hardtack. Project 2.8. Fallout Measurements by Aircraft and Rocket Sampling,

DTIC Science & Technology

1985-09-01

EXTRICTED WVE O OPERATION HARDTACK-PROJECT 2.8 Fallout Measurements by Aircraft and Rocket Sampling S. L. Whitcher L R. Bunney R. R. Soule U.S. Naval...Aircraft and Rocket Sampling , Extracted Version 12. PERSONAL AUTHOR(S) Whitcher, S.L.; Bunney, L.R.; Soule , R.R.; and daRoza, R.A. 13a. TYPE OF REPORT 13b...ROCKET SAMPLING S. L. Whitcher L.R. Bunney Rt. R. Soule , Project Officer U.S. Nav2l Radiological Defense Laboratory San Francisco 24, California R.A

Contamination by I-131 from Fall-out. Report No. 75; CONTAMINACION POR I$sup 131$ DEBIDA AL FALL-OUT. INFORME NO. 75

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benninson, D.; Ramos, E.

1962-01-01

The mean levels of I/sup 131/ in the milk of Buenos Aires from the last of April to the last of July 1962 were determined, and the significance of the results was discussed. The results showed that from May 16 to the first days of July there was a detectable iodine activity in the milk. An estimation was made of the thyroid dose received at different ages from the milk contamination. (J.S.R.)

Twenty-year review of medical findings in a Marshallese population accidentally exposed to radioactive fallout

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conard, R.A.

1975-01-01

A summary is presented of results of medical examinations of inhabitants of the Marshall Islands during the 20-year period following the exposure of Rongelap people to radioactive fallout in 1954. The initial effect observed was $beta$ burns of the skin of some individuals. Few significant findings were observed during the subsequent 9-year period, although an increase in miscarriages and stillbirths among the exposed women was noted. In 1963 some thyroid abnormalities and growth retardation of some children were noted. (177 references). (CH)

Operation CASTLE. Project 2.7. Distribution of Radioactive Fallout by Survey and Analyses of Sea Water

DTIC Science & Technology

1981-04-01

approximately 5,000 square miles can bo covered by contamination at levels that would be hazardous to human life if the fallout had been deposited on a...shots over larger areas was necessary. On Shot 5 alternative methods were attempted. The Division of Biology and Medicine (DBM) of the Atomic...tvoluotion.nott, howtvtf, thai it it •mall Pont« «ithin Larga Cirelt-Com^iM ovtroll ml- Inity tf Mark II «htn uud «uk mtr^ad in « atar which it cantam

Rapid Debris Analysis Project Task 3 Final Report - Sensitivity of Fallout to Source Parameters, Near-Detonation Environment Material Properties, Topography, and Meteorology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldstein, Peter

2014-01-24

This report describes the sensitivity of predicted nuclear fallout to a variety of model input parameters, including yield, height of burst, particle and activity size distribution parameters, wind speed, wind direction, topography, and precipitation. We investigate sensitivity over a wide but plausible range of model input parameters. In addition, we investigate a specific example with a relatively narrow range to illustrate the potential for evaluating uncertainties in predictions when there are more precise constraints on model parameters.

Surface Exposure Geochronology Using Cosmogenic Nuclides: Applications in Antarctic Glacial Geology

DTIC Science & Technology

1994-02-01

Department of Marine Chemistry and Geochemistry Dist Special Dean of Graduate Studies I I I SURFACE EXPOSURE GEOCHRONOLOGY USING COSMOGENIC NUCLIDES... studies of Sirius Group tills. Comparison of measured 10Be concentrations in Sirius Group deposits with those predicted with a model of the effects of...that this deposit does not, 1 as previous studies suggested, represent a single ice advance in response to lowered sea level at the last glacial

Radio-nuclide mixture identification using medium energy resolution detectors

DOEpatents

Nelson, Karl Einar

2013-09-17

According to one embodiment, a method for identifying radio-nuclides includes receiving spectral data, extracting a feature set from the spectral data comparable to a plurality of templates in a template library, and using a branch and bound method to determine a probable template match based on the feature set and templates in the template library. In another embodiment, a device for identifying unknown radio-nuclides includes a processor, a multi-channel analyzer, and a memory operatively coupled to the processor, the memory having computer readable code stored thereon. The computer readable code is configured, when executed by the processor, to receive spectral data, to extract a feature set from the spectral data comparable to a plurality of templates in a template library, and to use a branch and bound method to determine a probable template match based on the feature set and templates in the template library.

Multilayer Network Analysis of Nuclear Reactions

NASA Astrophysics Data System (ADS)

Zhu, Liang; Ma, Yu-Gang; Chen, Qu; Han, Ding-Ding

2016-08-01

The nuclear reaction network is usually studied via precise calculation of differential equation sets, and much research interest has been focused on the characteristics of nuclides, such as half-life and size limit. In this paper, however, we adopt the methods from both multilayer and reaction networks, and obtain a distinctive view by mapping all the nuclear reactions in JINA REACLIB database into a directed network with 4 layers: neutron, proton, 4He and the remainder. The layer names correspond to reaction types decided by the currency particles consumed. This combined approach reveals that, in the remainder layer, the β-stability has high correlation with node degree difference and overlapping coefficient. Moreover, when reaction rates are considered as node strength, we find that, at lower temperatures, nuclide half-life scales reciprocally with its out-strength. The connection between physical properties and topological characteristics may help to explore the boundary of the nuclide chart.

Rapid sequential determination of Pu, 90Sr and 241Am nuclides in environmental samples using an anion exchange and Sr-Spec resins.

PubMed

Lee, M H; Ahn, H J; Park, J H; Park, Y J; Song, K

2011-02-01

This paper presents a quantitative and rapid method of sequential separation of Pu, (90)Sr and (241)Am nuclides in environmental soil samples with an anion exchange resin and Sr Spec resin. After the sample solution was passed through an anion exchange column connected to a Sr Spec column, Pu isotopes were purified from the anion exchange column. Strontium-90 was separated from other interfering elements by the Sr Spec column. Americium-241 was purified from lanthanides by the anion exchange resin after oxalate co-precipitation. Measurement of Pu and Am isotopes was carried out using an α-spectrometer. Strontium-90 was measured by a low-level liquid scintillation counter. The radiochemical procedure of Pu, (90)Sr and (241)Am nuclides investigated in this study validated by application to IAEA reference materials and environmental soil samples. Copyright © 2010 Elsevier Ltd. All rights reserved.

Induction of osteosarcoma and acute myeloid leukaemia in CBA/H mice by the alpha-emitting nuclides, uranium-233, plutonium-239 and amercium-241.

PubMed

Ellender, M; Harrison, J D; Pottinger, H; Thomas, J M

2001-01-01

To compare tumour induction in CBA/H mice, principally osteosarcoma and acute myeloid leukaemia, resulting from exposure to the alpha-emitting nuclides, uranium-233, plutonium-239 and americium-241, and to relate differences between the three nuclides to the pattern of dose delivery within tissues. Each nuclide was administered intraperitoneally in citrate solution to three groups of adult male CBA/H mice at levels of activity which gave estimated life-time average skeletal doses of about 0.25-0.3 Gy, 0.5-1 Gy and 1-2 Gy. Animals were carefully monitored and sacrificed as soon as they showed signs of ill health; tumours were identified by standard histopathological techniques. Statistical modelling by Cox regression showed that, considering all three nuclides together, there was a highly significant increase in risk of death from osteosarcoma or myeloid leukaemia with increasing dose rate. For osteosarcoma, the effect was significantly greater for 239Pu than 241Am, while separate analysis for 233U showed no significant increase with increasing dose rate. For example, the increase in relative risk of death from osteosarcoma for an increase in life-time average dose rate to bone of 1 mGyd(-1) was 4.2 (2.7-6.5) for 239Pu, 2.3 (1.4-3.4) for 241Am and 1.1 (0.4-3.1) for 233U. For myeloid leukaemia, there was no significant difference between 239Pu and 241Am in the effect of dose rate. The increase in relative risk from myeloid leukaemia for an increase in average dose rate of 1 mGyd(-1) was 1.8 (1.1-2.8) for 239Pu, 2.0 (1.4-2.9) for 241Am and 1.5 (0.8-2.7) for 233U. Significant increases in renal and hepatic carcinomas were also recorded in animals exposed to 233U and 241Am, respectively. Studies of the distribution of the nuclides within the skeleton, published separately, have shown differences in their retention in individual bones and within bone. The proportions of decays occurring near to endosteal bone surfaces and throughout bone marrow were in the order: 239Pu> 241Am>233U. For osteosarcoma, the relative effectiveness of the nuclides in terms of average bone dose, in the order 239Pu>241Am>233U, is consistent with the proportion of dose delivered near to endosteal surfaces. For myeloid leukaemia, the greater effectiveness of 239Pu and 241Am than 233U is consistent with their accumulation in marrow.

Development of the MCNPX depletion capability: A Monte Carlo linked depletion method that automates the coupling between MCNPX and CINDER90 for high fidelity burnup calculations

NASA Astrophysics Data System (ADS)

Fensin, Michael Lorne

Monte Carlo-linked depletion methods have gained recent interest due to the ability to more accurately model complex 3-dimesional geometries and better track the evolution of temporal nuclide inventory by simulating the actual physical process utilizing continuous energy coefficients. The integration of CINDER90 into the MCNPX Monte Carlo radiation transport code provides a high-fidelity completely self-contained Monte-Carlo-linked depletion capability in a well established, widely accepted Monte Carlo radiation transport code that is compatible with most nuclear criticality (KCODE) particle tracking features in MCNPX. MCNPX depletion tracks all necessary reaction rates and follows as many isotopes as cross section data permits in order to achieve a highly accurate temporal nuclide inventory solution. This work chronicles relevant nuclear history, surveys current methodologies of depletion theory, details the methodology in applied MCNPX and provides benchmark results for three independent OECD/NEA benchmarks. Relevant nuclear history, from the Oklo reactor two billion years ago to the current major United States nuclear fuel cycle development programs, is addressed in order to supply the motivation for the development of this technology. A survey of current reaction rate and temporal nuclide inventory techniques is then provided to offer justification for the depletion strategy applied within MCNPX. The MCNPX depletion strategy is then dissected and each code feature is detailed chronicling the methodology development from the original linking of MONTEBURNS and MCNP to the most recent public release of the integrated capability (MCNPX 2.6.F). Calculation results of the OECD/NEA Phase IB benchmark, H. B. Robinson benchmark and OECD/NEA Phase IVB are then provided. The acceptable results of these calculations offer sufficient confidence in the predictive capability of the MCNPX depletion method. This capability sets up a significant foundation, in a well established and supported radiation transport code, for further development of a Monte Carlo-linked depletion methodology which is essential to the future development of advanced reactor technologies that exceed the limitations of current deterministic based methods.

Investigating the Usefulness of Cosmogenic in situ 14C for the Dating of Alluvial Fan Surfaces

NASA Astrophysics Data System (ADS)

Goehring, B. M.; Blisniuk, K.; Moon, S.

2017-12-01

Accurate and unambiguous constraints on the age of alluvial fan surfaces remain one of the ultimate achievements for the application of cosmogenic nuclides exposure dating. Information on the age of a fan is not only useful for understanding the rate of sediment transfer from adjacent hillslopes, but also the displacement of an alluvial fan surface and their incised channels represent one of the clearest markers of long-term (102 - 104 years) slip along faults in many regions. Common nuclides such as 10Be, 26Al, and 36Cl, which are often applied to dating alluvial fans, are hampered by inheritance due to their long half-life as nuclides accumulate during exhumation and transport. Here, we present results from a systematic study investigating the usefulness of the cosmogenic nuclide carbon-14 (14C) from the Ash Wash Fan of the Anza Borrego Desert, California, which is well-dated with both 10Be of amalgamated boulder surfaces and U-series ages from pedogenic carbonates. We sampled individual boulders from multiple fan channel bars, rather than an amalgamation of many boulders from a single fan channel bar. Our new14C results yield a median ± half-interquartile age of 4.7 ± 0.8 ka (n = 4, 1 outlier removed). These results are in excellent agreement with the existing U-series and new p-IR-IRSL chronology (5.2 ± 0.3 ka and 5.5 ± 0.8 ka, respectively), but slightly younger than the previously published 10Be amalgamation date of 7.0 ± 1.0 ka. In contrast, 10Be exposure dates of the same boulder in our study yield a median ± half-interquartile age of 10.9 ± 2.6 ka, which we interpret to be the result of insufficient burial time during transport and/or erosion of the boulder to remove accumulated 10Be. Our results suggest that 14C may be a viable chronometer of alluvial fan surfaces less than ca. 25 ka. Finally, inspired by approaches in the burial dating community, we will also explore the possibility of a paired nuclide isochron approach. Measured 14C and 10Be concentrations display a strong correlation (r2 = 0.9), suggesting there may be gains to be made using a paired nuclide approach; we will explore this relationship further in the presentation.

Role of Core-collapse Supernovae in Explaining Solar System Abundances of p Nuclides

NASA Astrophysics Data System (ADS)

Travaglio, C.; Rauscher, T.; Heger, A.; Pignatari, M.; West, C.

2018-02-01

The production of the heavy stable proton-rich isotopes between 74Se and 196Hg—the p nuclides—is due to the contribution from different nucleosynthesis processes, activated in different types of stars. Whereas these processes have been subject to various studies, their relative contributions to Galactic chemical evolution (GCE) are still a matter of debate. Here we investigate for the first time the nucleosynthesis of p nuclides in GCE by including metallicity and progenitor mass-dependent yields of core-collapse supernovae (ccSNe) into a chemical evolution model. We used a grid of metallicities and progenitor masses from two different sets of stellar yields and followed the contribution of ccSNe to the Galactic abundances as a function of time. In combination with previous studies on p-nucleus production in thermonuclear supernovae (SNIa), and using the same GCE description, this allows us to compare the respective roles of SNeIa and ccSNe in the production of p-nuclei in the Galaxy. The γ process in ccSN is very efficient for a wide range of progenitor masses (13 M ⊙–25 M ⊙) at solar metallicity. Since it is a secondary process with its efficiency depending on the initial abundance of heavy elements, its contribution is strongly reduced below solar metallicity. This makes it challenging to explain the inventory of the p nuclides in the solar system by the contribution from ccSNe alone. In particular, we find that ccSNe contribute less than 10% of the solar p nuclide abundances, with only a few exceptions. Due to the uncertain contribution from other nucleosynthesis sites in ccSNe, such as neutrino winds or α-rich freeze out, we conclude that the light p-nuclides 74Se, 78Kr, 84Sr, and 92Mo may either still be completely or only partially produced in ccSNe. The γ-process accounts for up to twice the relative solar abundances for 74Se in one set of stellar models and 196Hg in the other set. The solar abundance of the heaviest p nucleus 196Hg is reproduced within uncertainties in one set of our models due to photodisintegration of the Pb isotopes 208,207,206Pb. For all other p nuclides, abundances as low as 2% of the solar level were obtained.

Establishment of the low-level radwaste classification using the dose-to-curie technique at the Lan-Yu Temporary Storage Site, Taiwan

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, J.Y.; Lang, T.C.; Wei, H.J.

2007-07-01

The Fuel Cycle and Materials Administration (FCMA) in Taiwan announced a Supplementary Regulation for Classification of Low Radioactive Wastes, as well as the Regulation for Disposing of Low Radioactive Wastes and its Facility Safety Management in July 17, 1997, and September 10, 2003, respectively. The latter regulation states that in the future, before delivering low-level radioactive waste to a final land disposal site, each waste drum must specify the nuclide activity and be classified as class A, B, C or greater than C. The nuclide activity data for approximately 100,000 drums of low-level radwaste at the Lan-Yu temporary storage sitemore » accumulated in 1982-1995, therefore, must be established according to the above regulations. The original waste database at the Lan-Yu site indicates that the data were absent for about 9% and 72% of Co-60 and Cs-137 key nuclide activities, respectively. One of the principal tasks in this project was to perform whole drum gamma radioactivity analysis and contact dose rate counting to establish the relationship of dose-to-curie (D-to-C) of specific waste stream to derive gamma radioactivity of counting drums for 2 trenches repackaged at the Lan-Yu site. Utilizing regression function of Microsoft Excel and collected gamma data, a dose-to-curie relationship for the whole-drum radwaste is estimated in this study. Based on the relationship between radioactivity of various nuclides and the surface dose rate, an empirical function of the dose rate (Dose) associated with product of nuclide activity (Curie) and energy (Energy), CE is set up. Statistical data demonstrated that 838 whole drums were counted employing D-to-C approach to classify other 3,279 drums, and only the contact dose rate was detected for roughly 75% of the drums to estimate gamma radioactivity of whole drums, which can save considerable cost, time, and manpower. The 4,508 drums were classified as A and 7 drums as C after repackaging was complete. The estimation of D-to-C relationship was near 80% in those sorted drums. This methodology can provide a simple, easy and cost-effective way for inferring gamma nuclide activity. (authors)« less

On water in volcanic clouds

NASA Astrophysics Data System (ADS)

Durant, Adam J.

2007-12-01

Volcanic clouds and tephra fallout present a hazard to aviation, human and animal health (direct inhalation or ingestion, contamination of water supplies), and infrastructure (building collapse, burial of roads and railways, agriculture, abrasive and chemical effects on machinery). Understanding sedimentation processes is a fundamental component in the prediction of volcanic cloud lifetime and fallout at the ground, essential in the mitigation of these hazards. The majority of classical volcanic ash transport and dispersion models (VATDM) are based solely on fluid dynamics. The non-agreement between VATDM and observed regional-scale tephra deposit characteristics is especially obvious at large distances from the source volcano. In meteorology, the processes of hydrometeor nucleation, growth and collection have been long-established as playing a central role in sedimentation and precipitation. Taking this as motivation, the hypothesis that hydrometeor formation drives sedimentation from volcanic clouds was tested. The research objectives of this dissertation are: (1) To determine the effectiveness of tephra particles in the catalysis of the liquid water to ice phase transformation, with application to ice hydrometeor formation in volcanic clouds. (2) To determine the sedimentological characteristics of distal (100s km) tephra fallout from recent volcanic clouds. (3) To assess particle fallout rates from recent volcanic clouds in the context of observed deposit characteristics. (4) To assess the implications of hydrometeor formation on the enhancement of volcanic sedimentation and the potential for cloud destabilization from volcanic hydrometeor sublimation. Dissertation Overview. The following chapters present the analysis, results and conclusions of heterogeneous ice nucleation experiments and sedimentological characterization of several recent tephra deposits. The dissertation is organized in three chapters, each prepared in journal article format. In Chapter 1, single ash particle freezing experiments were carried out to investigate the effect of ash particle composition and surface area on water drop freezing temperature. In Chapter 2, the tephra deposit from the 18 May 1980 eruption of Mount St. Helens, USA, was reanalyzed using laser diffraction particle size analysis and hydrometeor-induced sedimentation mechanisms are considered. In Chapter 3, fallout from the 18 August 1992 and 16--17 September 1992 eruptions of Mount Spurr, USA, was analyzed and particle sedimentation and cloud microphysics were modeled to assess the potential for cloud destabilization from hydrometeor sublimation.

Simulating the Transfer of Strontium-90 from Soil to Leafy Vegetables by Using Strontium-88.

PubMed

Kuke, Ding; Shujuan, Liu; Yingxue, He; Dong, Yan; Fengshou, Zhang; Shuifeng, Wang; Jinghua, Guo; Wei, Zhang; Xin, Wang; Xiaoyan, Jiang

The transfer, from soil to Chinese cabbage and spinach, of radioactive strontium-90 released as a result of accidents in nuclear power stations was studied using a stable isotope of strontium, namely nuclide strontium-88 ( 88 Sr). The study led to an experimental model for assessing the hazard of radionuclide strontium-90 ( 90 Sr) entering the food chain and for predicting the risk to food safety. Chinese cabbage and spinach were grown in pots in a greenhouse and irrigated with deionized water containing known quantities of strontium. Based on the strontium content of that water, the plants were divided into five groups (treatments) and strontium content of the soil, and 30-day-old plants were determined by inductively coupled plasma atomic emission spectroscopy instrument (ICP-AES). Data on the strontium content of soil and plants enabled the development of a model using MATLAB, a mathematical software package, which included curve fitting and problem solving using regression equations and differential equations. Although strontium curves for leaves, stems, and roots of Chinese cabbage were not exactly the same, all showed a non-linear increase when compared with the increase in the content of strontium in soil. Strontium curves for leaves, stems, and roots of spinach were very similar and showed an initial increase followed by a decrease. Strontium concentrations in both Chinese cabbage and spinach were initially related to the concentrations of sodium and sulfur, the next two relevant nuclides being calcium and magnesium. The relationship between calcium and strontium in Chinese cabbage was different from that in spinach. By using 88 Sr to simulate the transfer of radionuclide 90 Sr from soil to a crop, the relevant data required to deal with accidental release of strontium can be obtained using a fitting curve and regression equations, thereby providing some experimental basis for evaluating the potential hazards posed by such accidents to the food chain.

Arrival of the Fukushima radioactivity plume in North American continental waters

PubMed Central

Smith, John N.; Brown, Robin M.; Williams, William J.; Robert, Marie; Nelson, Richard; Moran, S. Bradley

2015-01-01

The large discharge of radioactivity into the northwest Pacific Ocean from the 2011 Fukushima Dai-ichi nuclear reactor accident has generated considerable concern about the spread of this material across the ocean to North America. We report here the first systematic study to our knowledge of the transport of the Fukushima marine radioactivity signal to the eastern North Pacific. Time series measurements of 134Cs and 137Cs in seawater revealed the initial arrival of the Fukushima signal by ocean current transport at a location 1,500 km west of British Columbia, Canada, in June 2012, about 1.3 y after the accident. By June 2013, the Fukushima signal had spread onto the Canadian continental shelf, and by February 2014, it had increased to a value of 2 Bq/m3 throughout the upper 150 m of the water column, resulting in an overall doubling of the fallout background from atmospheric nuclear weapons tests. Ocean circulation model estimates that are in reasonable agreement with our measured values indicate that future total levels of 137Cs (Fukushima-derived plus fallout 137Cs) off the North American coast will likely attain maximum values in the 3–5 Bq/m3 range by 2015–2016 before declining to levels closer to the fallout background of about 1 Bq/m3 by 2021. The increase in 137Cs levels in the eastern North Pacific from Fukushima inputs will probably return eastern North Pacific concentrations to the fallout levels that prevailed during the 1980s but does not represent a threat to human health or the environment. PMID:25548181

European roe deer antlers as an environmental archive for fallout (236)U and (239)Pu.

PubMed

Froehlich, M B; Steier, P; Wallner, G; Fifield, L K

2016-01-01

Anthropogenic (236)U and (239)Pu were measured in European roe deer antlers hunted between 1955 and 1977 which covers and extends beyond the period of intensive nuclear weapons testing (1954-1962). The antlers were hunting trophies, and hence the hunting area, the year of shooting and the approximate age of each animal is given. Uranium and plutonium are known to deposit in skeletal tissue. Since antler histology is similar to bone, both elements were expected in antlers. Furthermore, roe deer shed their antlers annually, and hence antlers may provide a time-resolved environmental archive for fallout radionuclides. The radiochemical procedure is based on a Pu separation step by anion exchange (Dowex 1 × 8) and a subsequent U purification by extraction chromatography using UTEVA(®). The samples were measured by Accelerator Mass Spectrometry at the VERA facility (University of Vienna). In addition to the (236)U and (239)Pu concentrations, the (240)Pu/(239)Pu isotopic ratios were determined with a mean value of 0.172 ± 0.023 which is in agreement with the ratio of global fallout (∼0.18). Rather high (236)U/(238)U ratios of the order of 10(-6) were observed. These measured ratios, where the (236)U arises only from global fallout, have implications for the use of the (236)U/(238)U ratio as a fingerprint for nuclear accidents or releases from nuclear facilities. Our investigations have shown the potential to use antlers as a temporally resolved archive for the uptake of actinides from the environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fukushima-derived fission nuclides monitored around Taiwan: Free tropospheric versus boundary layer transport

NASA Astrophysics Data System (ADS)

Huh, Chih-An; Hsu, Shih-Chieh; Lin, Chuan-Yao

2012-02-01

The 2011 Fukushima nuclear accident in Japan was the worst nuclear disaster following the 1986 Chernobyl accident. Fission products (nuclides) released from the Fukushima plant site since March 12, 2011 had been detected around the northern hemisphere in about two weeks and also in the southern hemisphere about one month later. We report here detailed time series of radioiodine and radiocesium isotopes monitored in a regional network around Taiwan, including one high-mountain and three ground-level sites. Our results show several pulses of emission from a sequence of accidents in the Fukushima facility, with the more volatile 131I released preferentially over 134Cs and 137Cs at the beginning. In the middle of the time series, there was a pronounced peak of radiocesium observed in northern Taiwan, with activity concentrations of 134Cs and 137Cs far exceeding that of 131I during that episode. From the first arrival time of these fission nuclides and their spatial and temporal variations at our sampling sites and elsewhere, we suggest that Fukushima-derived radioactive nuclides were transported to Taiwan and its vicinity via two pathways at different altitudes. One was transported in the free troposphere by the prevailing westerly winds around the globe; the other was transported in the planetary boundary layer by the northeast monsoon wind directly toward Taiwan.

The NUBASE2016 evaluation of nuclear properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Audi, G.; Kondev, F. G.; Wang, Meng

This paper presents the NUBASE2016 evaluation that contains the recommended values for nuclear and decay properties of 3437 nuclides in their ground and excited isomeric (T1/2≥100 ns) states. All nuclides for which any experimental information is known were considered. NUBASE2016 covers all data published by October 2016 in primary (journal articles) and secondary (mainly laboratory reports and conference proceedings) references, together with the corresponding bibliographical information. During the development of NUBASE2016, the data available in the “Evaluated Nuclear Structure Data File” (ENSDF) database were consulted and critically assessed for their validity and completeness. Furthermore, a large amount of new datamore » and some older experimental results that were missing from ENSDF were compiled, evaluated and included in NUBASE2016. The atomic mass values were taken from the “Atomic Mass Evaluation” (AME2016, second and third parts of the present issue). In cases where no experimental data were available for a particular nuclide, trends in the behavior of specific properties in neighboring nuclides (TNN) were examined. This approach allowed to estimate values for a range of properties that are labeled in NUBASE2016 as “non-experimental” (flagged “#”). Evaluation procedures and policies used during the development of this database are presented, together with a detailed table of recommended values and their uncertainties. AMDC: http://amdc.impcas.ac.cn/« less

Assessment of resuspended matter and redistribution of macronutrient elements produced by boat disturbance in a eutrophic lagoon.

PubMed

Lenzi, Mauro; Finoia, Maria Grazia; Gennaro, Paola; Mercatali, Isabel; Persia, Emma; Solari, Jacopo; Porrello, Salvatore

2013-07-15

Harvesting of macroalgae by specially equipped boats in a shallow eutrophic lagoon produces evident sediment resuspension. To outline the environmental effects of this disturbance, we examined the quantity of fall-out and the distances travelled by sediment and macronutrients from the source of boat disturbance. Resuspended sediment fall-out (RSFO) was trapped at different distances from the boat path to determine total dry weight, total nitrogen (TN), total carbon (TC), total organic carbon (TOC), total sulphur (TS) and total phosphorus (TP). The data was analysed by principal components analysis (PCA) and linear discriminant analysis (LDA) on PCA factors. Fall-out of C, N, S and P from the plume of resuspended sediment indicated significant re-arrangement of these nutrients: RSFO dry weight and S content decreased with distance from the boat path, whereas TP increased and was the variable responsible for most discrimination at 100 m. The mass of resuspended matter was relatively large, indicating that the boats considerably reshuffle lagoon sediment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dynamics of melt generation beneath mid-ocean ridge axes: Theoretical analysis based on 238- 230Th- 226Ra and 235U- 231Pa disequilibria

NASA Astrophysics Data System (ADS)

Qin, Zhenwei

1993-04-01

Although slow melting favors the generation of basaltic melt from a mantle matrix with large radioactive disequilibrium between two actinide nuclides ( MCKENZIE, 1985a), it results in long residence time in a magma chamber, during which the disequilibrium may be removed. An equilibrium melting model modified after MCKENZIE (1985a) is presented here which suggests that, for a given actinide parent-daughter pair, there exists a specific melting rate at which disequilibrium between these two nuclides reaches its maximum. This melting rate depends on the decay constant of the daughter nuclide concerned and the magma chamber volume scaled to that of its source. For a given scaled chamber size, large radioactive disequilibrium between two actinide nuclides in basalts will be observed if the melting rate is such that the residence time of the magma in the chamber is comparable to the mean life of the daughter nuclide. With a chamber size 1% in volume of the melting source, the melting rates at which maximum disequilibrium in basalts is obtained are 10 -7, 2 × 10 -7 and 3 × 10 -6y-1, respectively, for 238U- 230Th, 235U- 231Pa and 230Th- 226Ra. This implies that, while large disequilibrium between 238U- 230Th and between 235U- 231Pa may occur together, large 230Th- 226Ra disequilibrium will not coexist with large 238U- 230Th disequilibrium, consistent with some observations. The active mantle melting zone which supplies melt to a ridge axis is inferred to be only about 10 km thick and 50 km wide. The fraction of melt present in such a mantle source at any time is about 0.01 and 0.04, respectively, if melting rate is 10 -7 and 10 -6 y -1. The corresponding residence time of the residual melt in the matrix is 10 5 and 4 × 10 4y.

Dust and chemical erosion biases in cosmogenic nuclide studies: A factor-of-ten problem that could mask strong climatic effects on landscape evolution

NASA Astrophysics Data System (ADS)

Riebe, C. S.; Arvin, L.; Ferrier, K.; Aciego, S.

2017-12-01

Cosmogenic nuclides have been widely used to quantify erosion in mountain ranges around the world, creating a global database of erosion rates from climatically and lithologically diverse sites, and providing vital clues about how mountain landscape evolution is coupled to Earth's carbon cycle and thus global climate change over geologic timescales. Despite this wealth of data, few studies have observed the widely expected strong control of erosion rates by climatic factors such as precipitation and temperature. Here we show that cosmogenic nuclide studies are prone to biases due to dust deposition and chemical erosion, which together can obscure strong relationships between climate and erosion rates. Erosion rates of sites exposed to intense chemical weathering can be underestimated by two-fold due to chemical enrichment of the cosmogenic target mineral quartz — a result of its high chemical erosion resistance, which increases its residence time and thus reduces its apparent erosion rate compared to other soil minerals. Meanwhile, erosion rates of sites with rapid dust deposition can be overestimated by more than ten-fold, due to dust's contributions to soil mass and target mineral abundance. Compilations of dust fluxes and cosmogenic nuclide data suggest that steep climatic trends in erosion rates, ranging from slow erosion rates in dry settings to twenty-fold faster erosion rates in wet settings, could be largely masked by the combined effects of dust deposition and chemical erosion. We argue that these effects need to be quantified in many cosmogenic nuclide studies of erosion rates. Doing so will require dust input rates; soil depth and density; quartz-enrichment ratios in both saprolite relative to bedrock and soil relative to saprolite; and quartz concentrations in deposited dust. Failure to quantify these crucial parameters can lead to misinterpretation of the strength — and even the sign — of feedbacks between climate and erosion rates in mountain landscapes.

Timing of Expansions of the Quelccaya Ice Cap, Peru, and Implications for Cosmogenic Nuclide Production Rate Calibration

NASA Astrophysics Data System (ADS)

Lowell, T. V.; Kelly, M. A.; Applegate, P. J.; Smith, C. A.; Phillips, F. M.; Hudson, A. M.

2010-12-01

We calibrate the production rate of the cosmogenic nuclide beryllium-10 (10Be) at a low-latitude, high-elevation site, using nuclide concentrations measured in moraine boulders and an independent chronology determined with bracketing radiocarbon dates. The measurement of terrestrial cosmogenic nuclide (TCN) concentrations in earth surface materials has been an important development for understanding a host of earth surface processes. Uncertainty in cosmogenic nuclide production rates has hampered application of this method. Here, we contribute to the estimation of 10Be production rates by reporting both preliminary 10Be concentrations and independent radiocarbon dates from a low latitude, high elevation site. Our study site in the southeastern Peruvian Andes (~13.9°S, 70.9°W, 4850 m asl) is centered on a moraine set, known as the Huancané II moraines, that represents a ~4 km expansion of Quelccaya Ice Cap during late glacial time. At this location, organic material situated both stratigraphically below and above moraines in two adjacent valleys provide material for radiocarbon dating. Based on geomorphic arguments, we correlate results from the two valleys. The timing of ice cap margin advance is bracketed by 13 radiocarbon ages on organic material within the outermost Huancané II moraines that range from 13.6 to 12.5 ka. Two stratigraphic sections upvalley from the moraines yield 6 radiocarbon ages from 11.3 to 12.4 ka, indicating the time of retreat . We computed the probability density function that lies between these two sets of dates, and assign an age of 12.4 ka (+/-???) for the formation of the Huancané II moraines. Calculating beryllium-10 exposure dates from the measured concentrations yield exposure dates that significantly underestimate the independently determined age of the moraine (~8-30%), if existing production rate estimates are used. We suggest that the radiocarbon age for the moraines can be used as a robust independent calibration for 10Be production rates at this site.

Advances in associated-particle neutron probe diagnostics for substance detection

NASA Astrophysics Data System (ADS)

Rhodes, Edgar A.; Dickerman, Charles E.; Frey, Manfred

1995-09-01

The development and investigation of a small associated-particle sealed-tube neutron generator (APSTNG) shows potential to allow the associated-particle diagnostic method to be moved out of the laboratory into field applications. The APSTNG interrogates the inspected object with 14-MeV neutrons generated from the deuterium-tritium reaction and detects the alpha-particle associated with each neutron inside a cone encompassing the region of interest. Gamma-ray spectra of resulting neutron reactions identify many nuclides. Flight-times determined from detection times of the gamma-rays and alpha-particles can yield a separate course tomographic image of each identified nuclide, from a single orientation. Chemical substances are identified by comparing relative spectral line intensities with ratios of elements in reference compounds. The high-energy neutrons and gamma-rays penetrate large objects and dense materials. Generally, no collimators or radiation shielding are needed. Proof-of-concept laboratory experiments have been successfully performed for simulated nuclear, chemical warfare, and conventional munitions. Most recently, inspection applications have been investigated for radioactive waste characterization, presence of cocaine in propane tanks, and uranium and plutonium smuggling. Based on lessons learned with the present APSTNG system, an advanced APSTNG tube (along with improved high voltage supply and control units) is being designed and fabricated that will be transportable and rugged, yield a substantial neutron output increase, and provide sufficiently improved lifetime to allow operation at more than an order of magnitude increase in neutron flux.

Survival of the relocated population of the U. S. after a nuclear attack. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haaland, C.M.; Chester, C.V.; Wigner, E.P.

1976-06-01

The feasibility of continued survival after a hypothetical nuclear attack is evaluated for people relocated from high-risk areas during the crisis period before the attack. The attack consists of 6559 MT, of which 5951 MT are ground bursts on military, industrial, and urban targets. Relocated people are assumed to be adequately protected from fallout radiation by shelters of various kinds. The major problems in the postattack situation will be the control of exposure to fallout radiation, and prevention of severe food shortages to several tens of millions of people.

Radioactive fallout reconstruction from contemporary measurements of reservoir sediments.

PubMed

Krey, P W; Heit, M; Miller, K M

1990-11-01

The temporal history of atmospheric deposition to a watershed area can be preserved in the sediment of a lake or reservoir that is supplied by the watershed. The 137Cs and isotopic Pu concentrations with depth were determined in the sediments of two reservoirs, Enterprise and Deer Creek, which are located in widely separated regions of the state of Utah. Our data not only reconstruct the history of the total radioactive fallout in the area, but also permit estimating the contributions from global sources and from the Nevada Test Site detonations in the 1950s.

Nuclear Reactor Accident Fallout Artifacts: Unusual Black Spots on Digital Radiographs.

PubMed

Kashimura, Yasuhiro; Chida, Koichi

2015-12-01

The Fukushima nuclear power plant accident resulted in the discharge of radioactive particulate material into the atmosphere. Consequently, several hospitals in Japan have observed black spots on x-ray computed radiography (CR) images caused by particulate radioactive fallout. These black spots have no effect on human health. To reduce the influence of black spots on CR images, we need to erase latent images on imaging plates (IPs) immediately before clinical use and read the IPs soon after the x-ray examination. Alternatively, the contaminated felt of a cassette can be cleaned or exchanged, if possible.

Ash aggregation during the 11 February 2010 partial dome collapse of the Soufrière Hills Volcano, Montserrat

NASA Astrophysics Data System (ADS)

Burns, F. A.; Bonadonna, C.; Pioli, L.; Cole, P. D.; Stinton, A.

2017-04-01

On 11 February 2010, Soufrière Hills Volcano, Montserrat, underwent a partial dome collapse ( 50 × 106 m3) and a short-lived Vulcanian explosion towards the end. Three main pyroclastic units were identified N and NE of the volcano: dome-collapse pyroclastic density current (PDC) deposits, fountain-collapse PDC deposits formed by the Vulcanian explosion, and tephra-fallout deposits associated with elutriation from the dome-collapse and fountain-collapse PDCs (i.e. co-PDC fallout deposit). The fallout associated with the Vulcanian explosion was mostly dispersed E and SE by high altitude winds. All units N and NE of the volcano contain variable amounts and types of particle aggregates, although the co-PDC fallout deposit is associated with the largest abundance (i.e. up to 24 wt%). The size of aggregates found in the co-PDC fallout deposit increases with distance from the volcano and proximity to the sea, reaching a maximum diameter of 12 mm about 500 m from the coast. The internal grain size of all aggregates have nearly identical distributions (with Mdϕ ≈ 4-5), with particles in the size categories > 3 ϕ (i.e. < 250 μm) being distributed in similar proportions within the aggregates but in different proportions within distinct internal layers. In fact, most aggregates are characterized by a coarse grained central core occupying the main part of the aggregate, coated by a thin layer of finer ash (single-layer aggregates), while others have one or two additional layers accreted over the core (multiple-layer aggregates). Calculated aggregate porosity and settling velocity vary between 0.3 and 0.5 and 11-21 m s- 1, respectively. The aggregate size shows a clear correlation with both the core size and the size of the largest particles found in the core. The large abundance of aggregates in the co-PDC fallout deposits suggests that the buoyant plumes elutriated above PDCs represent an optimal environment for the formation (particle collision) and development (aggregate layering) of particle aggregates. However, specific conditions are required, including i) a large availability of water (in this case provided by the steam plumes associated with the entrance of PDCs into the ocean), ii) presence of plume regions with different grain-size features (i.e. both median size and sorting) that allows for the development of multiple layers, iii) strong turbulence that permits both particle collision and the transition of the aggregates through different plume regions, iv) presence of hot regions (e.g. PDCs) that promote aggregate preservation (in this case also facilitated by the presence of sea salt).

ENDF/B-IV fission-product files: summary of major nuclide data

DOE Office of Scientific and Technical Information (OSTI.GOV)

England, T.R.; Schenter, R.E.

1975-09-01

The major fission-product parameters [sigma/sub th/, RI, tau/sub 1/2/, E- bar/sub $beta$/, E-bar/sub $gamma$/, E-bar/sub $alpha$/, decay and (n,$gamma$) branching, Q, and AWR] abstracted from ENDF/B-IV files for 824 nuclides are summarized. These data are most often requested by users concerned with reactor design, reactor safety, dose, and other sundry studies. The few known file errors are corrected to date. Tabular data are listed by increasing mass number. (auth)

Nuclear Data Sheets for A = 142

NASA Astrophysics Data System (ADS)

Johnson, T. D.; Symochko, D.; Fadil, M.; Tuli, J. K.

2011-08-01

The 2000 Nuclear Data Sheets for A=142 by J. K. Tuli, with literature cutoff date of February 4, 2000, has been revised. The evaluated experimental data are presented for 16 known nuclides of mass 142 (Ba, Ce, Cs, Dy, Eu, Gd, Ho, I, La, Nd, Pm, Pr, Sm, Tb, Te, Xe). Comparing to the previous evaluation (2000Tu01) significant changes were done to the level schemes of Gd, Cs, Ce and Nd. For all nuclides, the more recent Q values have been added.

Nuclear Data Sheets for A-142

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, T.D.; Johnson,T.D.; Symochko,D.

The 2000 Nuclear Data Sheets for A = 142 by J. K. Tuli, with literature cutoff date of February 4, 2000, has been revised. The evaluated experimental data are presented for 16 known nuclides of mass 142 (Ba, Ce, Cs, Dy, Eu, Gd, Ho, I, La, Nd, Pm, Pr, Sm, Tb, Te, Xe). Comparing to the previous evaluation (2000Tu01) significant changes were done to the level schemes of Gd, Cs, Ce and Nd. For all nuclides, the more recent Q values have been added.

Proton induced activity in graphite - comparison between measurement and simulation

NASA Astrophysics Data System (ADS)

Kiselev, Daniela; Bergmann, Ryan; Schumann, Dorothea; Talanov, Vadim; Wohlmuther, Michael

2018-06-01

The Paul Scherrer Institut (PSI) operates the Meson production target stations E and M with 590 MeV protons at currents of up to 2.4 mA. Both targets consist of polycrystalline graphite and rotate with 1 Hz due to the high power deposition (40 kW at 2 mA) in Target E. The graphite wheel is regularly exchanged and disposed as radioactive waste after a maximum of 3 to 4 years in operation, which corresponds to about 30 to 40 Ah of proton fluence. For disposal, the nuclide inventory of the long-lived isotopes (T1/2 > 60 d) has to be calculated and reported to the authorities. Measurements of gamma emitters, as well as 3H, 10Be and 14C, were carried out using different techniques. The measured specific activities are compared to Monte Carlo particle transport simulations performed with MCNPX2.7.0 using the BERTINI-DRESNER-RAL (default model in MCNPX2.7.0) and INCL4.6/ABLA07 as nuclear reaction models.

Real time wide area radiation surveillance system (REWARD) based on 3d silicon and (CD,ZN)Te for neutron and gamma-ray detection

NASA Astrophysics Data System (ADS)

Disch, C.

2014-09-01

Mobile surveillance systems are used to find lost radioactive sources and possible nuclear threats in urban areas. The REWARD collaboration [1] aims to develop such a complete radiation monitoring system that can be installed in mobile or stationary setups across a wide area. The scenarios include nuclear terrorism threats, lost radioactive sources, radioactive contamination and nuclear accidents. This paper will show the performance capabilities of the REWARD system in different scnarios. The results include both Monte Carlo simulations as well as neutron and gamma-ray detection performances in terms of efficiency and nuclide identification. The outcomes of several radiation mapping survey with the entire REWARD system will also be presented.

Concentrations of plutonium and americium in plankton from the western Mediterranean Sea.

PubMed

Sanchez-Cabeza, Joan-Albert; Merino, Juan; Masqué, Pere; Mitchell, Peter I; Vintró, L León; Schell, William R; Cross, Lluïsa; Calbet, Albert

2003-07-20

Understanding the transfer of radionuclides through the food chain leading to man and in particular, the uptake of transuranic nuclides by plankton, is basic to assess the potential radiological risk of the consumption of marine products by man. The main sources of transuranic elements in the Mediterranean Sea in the past were global fallout and the Palomares accident, although at present smaller amounts are released from nuclear establishments in the northwestern region. Plankton from the western Mediterranean Sea was collected and analyzed for plutonium and americium in order to study their biological uptake. The microplankton fractions accounted for approximately 50% of the total plutonium contents in particulate form. At Garrucha (Palomares area), microplankton showed much higher 239,240 Pu activity, indicating the contamination with plutonium from the bottom sediments. Concentration factors were within the range of the values recommended by the International Atomic Energy Agency. Continental shelf mesoplankton was observed to efficiently concentrate transuranics. In open seawaters, concentrations were much lower. We speculate that sediments might play a role in the transfer of transuranics to mesoplankton in coastal waters, although we cannot discard that the difference in species composition may also play a role. In Palomares, both 239,240 Pu and 241Am showed activities five times higher than the mean values observed in continental shelf mesoplankton. As the plutonium isotopic ratios in the contaminated sample were similar to those found in material related to the accident, the contamination was attributed to bomb debris from the Palomares accident. Concentration factors in mesoplankton were also in relatively good agreement with the ranges recommended by IAEA. In the Palomares station the highest concentration factor was observed in the sample that showed predominance of the dynoflagellate Ceratium spp. Mean values of the enrichment factors showed, on average, discrimination rather than enrichment in the primary producer trophic chain.

Background radiation and individual dosimetry in the costal area of Tamil Nadu, India.

PubMed

Matsuda, Naoki; Brahmanandhan, G M; Yoshida, Masahiro; Takamura, Noboru; Suyama, Akihiko; Koguchi, Yasuhiro; Juto, Norimichi; Raj, Y Lenin; Winsley, Godwin; Selvasekarapandian, S

2011-07-01

South coast of India is known as the high-level background radiation area (HBRA) mainly due to beach sands that contain natural radionuclides as components of the mineral monazite. The rich deposit of monazite is unevenly distributed along the coastal belt of Tamil Nadu and Kerala. An HBRA site that laid in 2×7 m along the sea was found in the beach of Chinnavillai, Tamil Nadu, where the maximum ambient dose equivalent reached as high as 162.7 mSv y(-1). From the sands collected at the HBRA spot, the high-purity germanium semi-conductor detector identified six nuclides of thorium series, four nuclides of uranium series and two nuclides belonging to actinium series. The highest radioactivity observed was 43.7 Bq g(-1) of Th-228. The individual dose of five inhabitants in Chinnavillai, as measured by the radiophotoluminescence glass dosimetry system, demonstrated the average dose of 7.17 mSv y(-1) ranging from 2.79 to 14.17 mSv y(-1).

ESTIMATION OF EFFECTIVE DOSE FROM EXTERNAL EXPOSURE DUE TO SHORT-LIVED NUCLIDES IN THE PREFECTURES SURROUNDING FUKUSHIMA.

PubMed

Miyatake, Hirokazu; Yoshizawa, Nobuaki; Suzuki, Gen

2018-05-11

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted in a release of radionuclides into the environment. Since the accident, measurements of radiation in the environment such as air dose rate and deposition density of radionuclides have been performed by various organizations and universities. In particular, Japan Atomic Energy Agency (JAEA) has been performing observations of air dose rate using a car-borne survey system continuously over widespread areas. Based on the data measured by JAEA, we estimated effective dose from external exposure in the prefectures surrounding Fukushima. Since car-borne survey started a few months after the accident, the main contribution to measured data comes from 137Cs and 134Cs whose half-lives are relatively long. Using air dose rate of 137Cs and 134Cs and the ratio of deposition density of short-lived nuclides to that of 137Cs and 134Cs, we also estimated contributions to the effective dose from other short-lived nuclides.

Tricuspid regurgitation by radionuclide angiography and contrast right ventriculography: a preliminary observation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lumia, F.J.; Patil, A.; Germon, P.A.

In a retrospective study correlating the degree of tricuspid regurgitation seen on first-pass radionuclide angiography with that seen on contrast right ventriculography in 51 patients, ten had no tricuspid regurgitation by contrast ventriculography, whereas by radionuclide angiography nine had no regurgitation and one had minimal regurgitation. Of eight patients with minimal tricuspid regurgitation by contrast ventriculography, five had minimal regurgitation by nuclide angiography and three had no regurgitation. Of the 11 patients with mild to moderate tricuspid regurgitation by contrast studies, ten had mild to moderate regurgitation and one had severe regurgitation by nuclide angiography. Of 22 patients with moderatemore » to severe tricuspid regurgitation by contrast studies, 15 had moderate to severe regurgitation and seven had mild to moderate regurgitation by nuclear angiography. In this preliminary study comparing radionuclide angiography with contrast right ventriculography, there were three false-negative and one false-positive nuclide angiograms, giving a sensitivity of 93% and a specificity of 90%.« less

Studies on cosmogenic nuclides in meteorites with regard to an application as potential depth indicators

NASA Technical Reports Server (NTRS)

Sarafin, R.; Herpers, U.; Englert, P.; Wieler, R.; Signer, P.; Bonani, G.; Hofmann, H. J.; Morenzoni, E.; Nessi, M.; Suter, M.

1986-01-01

Measurements of stable and radioactive spallation products in meteorites allow to investigate their histories, especially with respect to the exposure to galactic cosmic ray particles and the pre-atmospheric size of the object. While the concentrations of spallation products lead to the determination of exposure and terrestrial ages, production rate ratios are characteristic for the location of the sample in the meteorite. So, one of the aims of this investigation on meteorites is to obtain depth indicators from suitable pairs of cosmogenic nuclides. Because of the different depth profiles for nuclide productions it is necessary to determine the concentrations of a larger number of spallation products in aliquots of a single small sample. Such same sample measurements of Be-10 and light noble gases were performed on 15 ordinary chondrites (7 H- and 8 L-chondrites. Be-10 was determined by accelerator mass spectrometry and the noble gases were measured by static mass spectrometry. The results are summarized and discussed.

Effects of fluvial processes in different order river valleys on redistribution and storage of particle-bound radioactive caesium-137 in area of significant Chernobyl fallout and impact on linked rivers with lower contamination levels

NASA Astrophysics Data System (ADS)

Belyaev, Vladimir; Golosov, Valentin; Shamshurina, Evgeniya; Ivanov, Maxim; Ivanova, Nadezhda; Bezukhov, Dmitry; Onda, Yuichi; Wakiyama, Yoshifumi; Evrard, Olivier

2015-04-01

Detailed investigations of the post-fallout fate of radionuclide contamination represent an important task in terms of environmental quality assessment. In addition, particle-bound radionuclides such as the most widespread anthropogenic isotope caesium-137 can be used as tracers for quantitative assessment of different sediment redistribution processes. In landscapes of humid plains with agriculture-dominated land use the post-fallout redistribution of caesium-137 is primarily associated with fluvial activity of various scales in cascade systems starting from soil erosion on cultivated hillslopes through gully and small dry valley network into different order perennial streams and rivers. Our investigations in the so-called Plavsk hotspot (area of very high Chernobyl caesium-137 contamination within the Plava River basin, Tula Region, Central European Russia) has been continuing for more than 15 years by now, while the time passed since the Chernobyl disaster and associated radioactive fallout (1986) is almost 29 years. Detailed information on the fluvial sediment and associated caesium-137 redistribution has been obtained for case study sites of different size from individual cultivated slopes and small catchments of different size (2-180 km2) to the entire Plava River basin scale (1856 km2). It has been shown that most of the contaminated sediment over the time passed since the fallout has remained stored within the small dry valleys of the 1-4 Hortonian order and local reservoirs (>70%), while only about 5% reached the 5-6 order valleys (main tributaries of the Plava River) and storage of the Plava floodplain itself represents as low as 0.3% of the basin-scale total sediment production from eroded cultivated hillslopes. Nevertheless, it has been shown that contaminated sediment yield from the Plava River basin exerts significant influence on less polluted downstream-linked river system. Recent progress of the investigations involved sampling of 7 detailed depth-incremental floodplain sediment sections along the Upa River valley, which is the receiving river for the Plava and is characterized by generally much lower caesium-137 contamination within other parts of its basin. One of the sampled sections was located several kilometers upstream from the Plava River mouth and the other 6 - at different distances downstream starting from about 2 km to about 40 km. In this case we can assume the Plava River mouth to be the point-source of sediment-associated radioactive contamination additional to the initial fallout. It has been found that while at the nearest point downstream the floodplain sediment contamination by caesium-137 is about 2 order of magnitude higher, than upstream, it decreases quickly along the Upa River valley two about 3 times higher than upstream at the most remote downstream point. Importantly, the decrease is not represented by gradual and uniform curve. In contrast, it is interrupted by local increase caused by smaller tributary from relatively high contamination area. It is believed that the obtained information on decadal-scale sediment and associated post-fallout caesium-137 redistribution through the fluvial network, patterns of sinks and rate of contamination propagation into the less polluted downstream-linked river basin can be used for testing and improving the predictive models being developed for applications in other contaminated areas such as river basins around the Fukushima Daiichi nuclear power plant, providing that differences in landscape settings, hydrological regime and land use patterns are taken into account.

Detection of fallout 241Am in U.S. Atlantic salt marsh soils

NASA Astrophysics Data System (ADS)

Boyd, B. M.; Sommerfield, C. K.

2017-09-01

We report the presence of the fallout radionuclide 241Am (t1/2 = 433 years) in salt marsh soils from two U.S. Atlantic estuaries and discuss its utility as a particle tracer and geochronometer. This work is motivated by the knowledge that 137Cs, the most widely used geochronometer in environmental studies, will decay to extinction during the next century. At the same time, levels of 241Am, produced by radioactive decay of fallout 241Pu, will continue to increase on Earth's surface as they have since the height of atmospheric nuclear weapons testing in the 1960s. Measurements of 241Am in soils at eighteen salt marsh locations were made by non-destructive gamma spectrometry and compared to activities of 137Cs in the same samples. Results indicate that decay of fallout 241Pu can explain the presence of 241Am in the soils, and that the activities are sufficiently high to provide meaningful chronological information with acceptable confidence limits. We achieved a detection limit of 0.28-1.47 Bq kg-1 using low-energy, planar germanium detectors and 11-55 g powderized samples. Activities of 241Am (0.08-6.44 Bq kg-1) were similar in mineral- and organic-rich marsh soils indicating that soil composition does not appear to influence the initial capture of 241Pu and retention of its 241Am progeny. Given its high affinity for fine particles, long half-life, and ease of measurement by non-destructive gamma spectrometry, 241Am has potential to serve as an alternative to 137Cs geochronometry in salt marshes and perhaps other estuarine and coastal environments.

Sedimentary record of plutonium in the North Yellow Sea and the response to catchment environmental changes of inflow rivers.

PubMed

Xu, Yihong; Pan, Shaoming; Gao, Jianhua; Hou, Xiaolin; Ma, Yongfu; Hao, Yongpei

2018-09-01

Plutonium (Pu) isotopes were first determined in surface and core sediment samples collected from the northern North Yellow Sea (NYS) to elucidate their source terms and deposition process as well as the response to catchment environmental changes of inflow rivers. 240 Pu/ 239 Pu atom ratios in all sediments showed the typical global fallout value of ∼0.18 without any influences from the nuclear weapons tests conducted recently in the North Korea or early in the Pacific Proving Ground. The large variation of 239+240 Pu activities (0.022-0.515 mBq/g) observed in surface sediments should be mainly attributed to the re-suspension and transportation of fine sediments influenced by the Liaonan Costal Current. Based on the two 239+249 Pu depth profiles with easily observed onset fallout levels (1952) and global fallout peaks (1963), 239+240 Pu served as a valid time mark in the coastal sedimentary system. Riverine input Pu contributed only 15-27% to the total global fallout inventory (92.5-108.8 Bq/m 2 ) in the northern NYS, much lower than that in the Yangtze River estuary (77-80%), indicating a better soil conservation in the northeast China due to higher forest coverage compared to the Yangtze River's drainage basin. The increase of riverine input Pu after 1980s reflected the more intense soil erosion degree caused by the land use and cover change due to the increment of human activities in the northeast China at the same period. Our results demonstrated that plutonium is a good indicator for studying sedimentary process and its response to the environment in the coastal area. Copyright © 2018 Elsevier Ltd. All rights reserved.

Marine radioactivity in the Arctic: a retrospect of environmental studies in Greenland waters with emphasis on transport of 90Sr and 137Cs with the East Greenland Current.

PubMed

Aarkrog, A; Dahlgaard, H; Nielsen, S P

1999-09-30

The waters around Greenland have received radioactive contamination from three major sources: Global fallout, discharges from the nuclear fuel reprocessing plant Sellafield in the UK, and the Chernobyl accident in the Former Soviet Union (FSU). The global fallout peaked in the early 1960s. The radiologically most important radionuclides from this source are 90Sr and 137Cs. The input of global fallout to arctic waters was direct deposition from the atmosphere and indirect delivery through river run off and advection from the Atlantic Ocean via the north-east Atlantic current system. The waterborne discharges from Sellafield which were at their peak between 1974 and 1981 contributed primarily 137Cs, although some 90Sr was also discharged. The Chernobyl accident in 1986 was characterised by its substantial atmospheric release of radiocaesium (134Cs and 137Cs). Other sources may, however, also have contributed to the radioactivity in the Greenland waters. Examples include La Hague, France, and radioactive discharges to the great Siberian rivers (Ob, Yenisey and Lena) from nuclear activities in the Former Soviet Union or the local fallout from the Novaya Zemlya nuclear weapons test site. Dumping of nuclear waste in the Kara and Barents Seas may be another, although minor source. From measurements in Greenland waters carried out since 1962 the transport of radionuclides with the East Greenland Current is calculated and compared with the estimated inputs of 90Sr and 137Cs to the Arctic Ocean. This study focus on 90Sr and 137Cs because the longest time series are available for these two radionuclides.

The long-term decrease of 90Sr availability in the environment and its transfer to man after a nuclear fallout.

PubMed

Mück, K; Sinojmeri, M; Whilidal, H; Steger, F

2001-01-01

Due to its long physical half-life, and the fact that its long-term mobility in the environment as well as its radiotoxicity is higher than that of 137Cs, the long-term bio-availability of 90Sr in the environment is of importance with regard to the long-term population exposure after fallout from nuclear weapons detonations or a severe reactor accident. It will also substantially influence the time-span required until re-utilisation of highly contaminated territory is possible again. An assessment of the long-term decrease of the activity concentration in all foodstuffs relevant for internal exposure after severe 90Sr fallout was performed. The observed effective half-lives were approximately 1.8-2.1 years in the first 2-3 years after the end of fallout and 8-10 years in the following three decades. This is equivalent to a biological half-life of about 13.2 years and results in a total 50 year dose of 6.2 times the first year exposure. Due to this decline in 90Sr-availability, the average annual activity intake of 90Sr in Austria has decreased from 840 Bq at the climax of the nuclear weapons tests to about 42 Bq in 1997 for adults, and from 500 Bq to about 35 Bq for 1 year old infants. This is equivalent to a 90Sr ingestion dose of 1.2 microSv for adults and 2.5 microSv for 1 year old infants in 1997 or less than 0.4% of the ingestion dose by natural radionuclides in the diet.

Radioactive contamination processes during 14-21 March after the Fukushima accident: What does atmospheric electric field measurements tell us?

NASA Astrophysics Data System (ADS)

Takeda, M.; Yamauchi, M.; Makino, M.; Owada, T.; Miyagi, I.

2012-04-01

Ionizing radiation from the radioactive material is known to increase atmospheric electric conductivity, and hence to decrease vertical downward atmospheric DC electric field at ground level, or potential gradient (PG). In the past, the drop of PG has been observed after rain-induced radioactive fallout (wet contamination) after nuclear tests or after the Chernobyl disaster. After the nuclear accident Fukushima Dai-ichi nuclear power plant (FNPP) that started 11 March 2011, the PG also at Kakioka, 150 km southwest from the FNPP, also dropped a by one order of magnitude. Unlike the past examples, the PG drop was two-stepped on 14 March and 20 March. Both correspond to two largest southward release of radioactive material according to the data from the radiation dose rate measurement network. We compare the Kakioka's PG data with the radiation dose rate data at different places to examine the fallout processes of both on 14 March and on 20 March. The former turned out to be dry contamination by surface wind, leaving a substantial amount of fallout floating near the ground. The latter turned out to be wet contamination by rain after transport by relatively low-altitude wind, and the majority of the fallout settled to the ground at this time. It is recommended that all nuclear power plant to have a network of PG observation surrounding the plant. Takeda, et al. (2011): Initial effect of the Fukushima accident on atmospheric electricity, Geophys. Res. Lett., 38, L15811, doi:10.1029/2011GL048511. Yamauchi, et al. (2012): Settlement process of radioactive dust to the ground inferred from the atmospheric electric field measurement, Ann. Geophys., 30, 49-56, doi:10.5194/angeo-30-49-2012.

Lessons learnt from a factory fire with asbestos-containing fallout.

PubMed

Bridgman, S A

1999-06-01

Fallout containing asbestos from a factory fire at Tranmere, Wirral, England, landed on a highly populated urban area with an estimated 16000 people living in the area worst affected, which included a shipbuilding community. There was considerable public concern over the health impact of the acute environmental incident, and great media interest. A descriptive study was carried out of the acute environmental incident and its management, and the difficulties encountered. Practical lessons learnt include need for: increased fire-fighter awareness of potential adverse health effects from asbestos in the structure of buildings; early involvement of both Local Authority environmental health and National Health Service public health departments; creation of a systematic local database of potential environmental health hazards in the structure of buildings as well as their contents; 24 hour on-call arrangements with laboratories expert in analyses of fire fallout; rapid quantitative analyses of multiple environmental samples; district written policy on handling asbestos incidents; systematic assessment of fright and media factors in public impact of an incident; dedicated public help-lines open long hours; consistent evidence-based public messages from all those communicating with the public; measurement of asbestos levels in the street and homes for public reassurance; local and health authorities' subscription to an environmental incident support service; formation of an acute environmental incident team to jointly manage and publicly report on airborne acute environmental incidents; clear government definition of responsibilities of different agencies. This paper provides a description of important lessons learnt during an acute environmental incident with asbestos-containing fallout. It will be helpful to those involved in the practical planning for and management of future incidents.

Use of anthropogenic radioisotopes to estimate rates of soil redistribution by wind II: The potential for future use of 239+240Pu

NASA Astrophysics Data System (ADS)

Van Pelt, R. Scott; Ketterer, Michael E.

2013-06-01

In the previous paper, the use of soilborne 137Cs from atmospheric fallout to estimate rates of soil redistribution, particularly by wind, was reviewed. This method relies on the assumption that the source of 137Cs in the soil profile is from atmospheric fallout following the period of atmospheric weapons testing so that the temporal and, to a certain extent, the spatial patterns of 137Cs deposition are known. One of the major limitations occurs when local or regional sources of 137Cs contamination mask the pulse from global fallout, making temporal estimates of redistribution difficult or impossible. Like 137Cs, Pu exhibits strong affinity for binding to soil particle surfaces, and therefore, re-distribution of Pu inventory indicates inferred soil re-distribution. Compared to 137Cs, 239Pu and 240Pu offer several important advantages: (a) the two major Pu isotopes have much longer half-lives than 137Cs and (b) the ratio 240Pu/239Pu is used to examine whether the Pu is from stratospheric fallout. In this paper, we review the literature concerning Pu in soil and of current attempts to use this tracer to estimate rates of soil redistribution. We also present preliminary, unpublished data from a pilot study designed to test whether or not 239+240Pu can be used to estimate rates of soil redistribution by wind. Based on similarities of profile distribution and relative inventories between 137Cs measurements and 239+240Pu measurements of split samples from a series of fields with documented wind erosion histories, we conclude that 239+240Pu may well be the anthropogenic radioisotope of choice for future soil redistribution investigations.

The removal of particle-reactive radionuclides in shallow water: Bottom scavenging versus particle settling of iodine-131 and beryllium-7.

PubMed

Montenero, Michael P; Dilbone, Elizabeth K; Waples, James T

2017-10-01

In pelagic waters, the removal of particle-reactive radionuclides is controlled by nuclide sorption to particles and subsequent settling by gravity. However, in shallow nearshore waters, the dominant mechanism of nuclide scavenging is not so clear. Understanding how particle-reactive radionuclides are scavenged from the water column is critical if these tracers are to be used as proxies of particle flux in shallow aquatic systems. In this study, we present evidence that the removal of particle-reactive radionuclides in nearshore and turbulent waters is primarily controlled by bottom scavenging. Specifically, we measured both water column and bottom sediment activities of sewage-sourced iodine-131 ( 131 I, t ½ = 8.02 days) and atmospherically-sourced beryllium-7 ( 7 Be, t ½ = 53.3 days) in a semi-enclosed harbor. We show that the water column 7 Be/ 131 I flux ratio that is required to sustain observed harbor bottom inventories of both nuclides is incongruent with 7 Be/ 131 I activity ratios on water column particles, and (2) 131 I and 7 Be derived mass fluxes of particulate matter to the harbor bottom are in concordance with each other and independently made estimates of river sediment loading to the harbor only when bottom scavenging of both particle-bound and dissolved (<0.7 μm) nuclide fractions are considered. Copyright © 2017 Elsevier Ltd. All rights reserved.

The NUBASE2016 evaluation of nuclear properties

NASA Astrophysics Data System (ADS)

Audi, G.; Kondev, F. G.; Wang, Meng; Huang, W. J.; Naimi, S.

2017-03-01

This paper presents the NUBASE2016 evaluation that contains the recommended values for nuclear and decay properties of 3437 nuclides in their ground and excited isomeric (T1/2 >= 100 ns) states. All nuclides for which any experimental information is known were considered. NUBASE2016 covers all data published by October 2016 in primary (journal articles) and secondary (mainly laboratory reports and conference proceedings) references, together with the corresponding bibliographical information. During the development of NUBASE2016, the data available in the 'Evaluated Nuclear Structure Data File' (ENSDF) database were consulted and critically assessed for their validity and completeness. Furthermore, a large amount of new data and some older experimental results that were missing from ENSDF were compiled, evaluated and included in NUBASE2016. The atomic mass values were taken from the 'Atomic Mass Evaluation' (AME2016, second and third parts of the present issue). In cases where no experimental data were available for a particular nuclide, trends in the behavior of specific properties in neighboring nuclides (TNN) were examined. This approach allowed to estimate values for a range of properties that are labeled in NUBASE2016 as 'non-experimental' (flagged '#'). Evaluation procedures and policies used during the development of this database are presented, together with a detailed table of recommended values and their uncertainties. AMDC: http://amdc.impcas.ac.cn/ Contents The NUBASE2016 evaluation of nuclear propertiesAcrobat PDF (1.1 MB) Table I. The NUBASE2016 table of nuclear and decay propertiesAcrobat PDF (706 KB)

Development and assessment of a simple ecological model (TRIPS) for forests contaminated by radiocesium fallout.

PubMed

Thiry, Yves; Albrecht, Achim; Tanaka, Taku

2018-10-01

The management of vast forested zones contaminated by radiocesium (rCs) following the Chernobyl and Fukushima fallout is of great social and economic concern in affected areas and requires appropriate dynamic models as predictive or questioning tools. Generally, the existing radio-ecological models need less fragmented data and more ecological realism in their quantitative description of the rCs cycling processes. The model TRIPS ("Transfer of Radionuclide In Perennial vegetation Systems") developed in this study privileged an integrated approach which makes the best use of mass balance studies and available explicit experimental data for Scots pine stands. A main challenge was the differentiation and calibration of foliar absorption as well as root uptake in order to well represent the rCs biocycling. The general dynamics of rCs partitioning was simulated with a relatively good precision against an independent series of observed values. In our scenario the rCs biological cycling enters a steady-state about 15 years after the atmospheric deposits. At that time, the simulations showed an equivalent contribution of foliage and root uptake to the tree contamination. But the root uptake seems not sufficient to compensate the activity decline in the tree. The initial foliar uptake and subsequent internal transfers were confirmed to have a great possible impact on the phasing of tree contamination. An extra finding concerns the roots system acting as a buffer in the early period. The TRIPS model is particularly useful in cases where site-specific integrated datasets are available, but it could also be used with adequate caution to generic sites. This development paves the way for simplification or integration of new modules, as well as for a larger number of other applications for the Chernobyl or Fukushima forests once the appropriate data become available. According to the sensitivity analysis that involves in particular reliable estimates of net foliar uptake as well as root uptake not disconnected from rCs exchange reactions in soil. Copyright © 2018 Elsevier Ltd. All rights reserved.

Simulating CRN derived erosion rates in a transient Andean catchment using the TTLEM model

NASA Astrophysics Data System (ADS)

Campforts, Benjamin; Vanacker, Veerle; Herman, Frédéric; Schwanghart, Wolfgang; Tenrorio Poma, Gustavo; Govers, Gerard

2017-04-01

Assessing the impact of mountain building and erosion on the earth surface is key to reconstruct and predict terrestrial landscape evolution. Landscape evolution models (LEMs) are an essential tool in this research effort as they allow to integrate our growing understanding of physical processes governing erosion and transport of mass across the surface. The recent development of several LEMs opens up new areas of research in landscape evolution. Here, we want to seize this opportunity by answering a fundamental research question: does a model designed to simulate landscape evolution over geological timescales allows to simulate spatially varying erosion rates at a millennial timescale? We selected the highly transient Paute catchment in the Southeastern Ecuadorian Andes as a study area. We found that our model (TTLEM) is capable to better explain the spatial patterns of ca. 30 Cosmogenic Radio Nuclide (CRN) derived catchment wide erosion rates in comparison to a classical, statistical approach. Thus, the use of process-based landscape evolution models may not only be of great help to understand long-term landscape evolution but also in understanding spatial and temporal variations in sediment fluxes at the millennial time scale.

Toxoplasma antibodies and retinochoroiditis in the Marshall Islands and their association with exposure to radioactive fallout

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, W.H.; Kindermann, W.R.; Walls, K.W.

1987-03-01

Nearly universal serologic evidence of Toxoplasma gondii infection was found to have occurred by adulthood in 517 Marshallese tested in 1981-1982. The prevalence and incidence of retinal lesions compatible with toxoplasmosis were 3.9% and 273 cases/year/100,000 seropositive persons, respectively, thus indicating a significant public health problem. Seronegativity was significantly more common in a subgroup of Marshallese that had received 110-190 rads of total-body gamma radiation as a consequence of accidental exposure to radioactive fallout in 1954. Despite this finding there was no evidence of an increase in clinically significant lesions in exposed persons.

Rad Resilient City: a preparedness checklist to save lives following a nuclear detonation.

PubMed

Schoch-Spana, Monica

2013-11-01

The Rad Resilient City Checklist is a local planning tool that can help save tens of thousands of lives following a nuclear detonation. If prevention of nuclear terrorism fails, then reducing exposure to radioactive fallout is the intervention that can save the most lives following a nuclear detonation. Yet, most Americans are not familiar with correct safety measures against fallout, and many believe that nothing can be done to reduce the suffering and death inflicted by a nuclear attack. Moreover, cities have no checklist on how to prepare the emergency management infrastructure and the larger population for this hazard, despite hundreds of pages of useful guidance from the federal government and radiation professional organizations. The Rad Resilient City Checklist reverses this situation by converting the latest federal guidance and technical reports into clear, actionable steps for communities to take to protect their residents from exposure to radioactive fallout. The checklist reflects the shared judgment of the Nuclear Resilience Expert Advisory Group, a national panel led by the Center for Biosecurity and comprised of government decision makers, scientific experts, emergency responders, and leaders from business, volunteer, and community sectors.

RADIOACTIVE CONTAMINATION OF FOOD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Setter, L.R.

The environment and, consequently, food contains measurable amounts of radionuclides arising primarily from the distribution of nuclear bomb debris over the entire earth's surface. This radioactivity is in addition to natural radioactivity which exists in thc environment. A wealth of information has been gathered on the artificial radioactivity in air, water, vegetation, and soil; on physical and chemical mechanisms of radioaetive movement in the biosphere; and on the biologic behavior of radionuclide uptake by animals and human beings and their distribution in excretions and secretions. Collection of additional information under more carefully designed and executed studies is under way. Theremore » remains the task of marshalling and reviewing the data obtained during active fall-out up to the summer of 1959. With later information collected during a period of substantially no fall-out, the interpretation of these data hopefully will indicate the relative magnitude of physical, chemical, and biologic factors influencing levels in plants and animals, provide a means of predicting future levels, and, most important, permit some evaluation of the effects of nuclear radiation from ingestion of contaminated food as a part of the total effects from fall-out and from natural radioactivity. (auth)« less

Fallout, radiation doses near Dounreay, and childhood leukaemia.

PubMed Central

Darby, S C; Doll, R

1987-01-01

Possible explanations for the recently reported increased incidence of childhood leukaemia around Dounreay were examined in the light of changes in the national incidence of leukaemia that occurred during the period of exposure to fallout from international testing of nuclear weapons in the atmosphere. It was concluded that the increase could not be accounted for by an underestimate of the risk of leukaemia per unit dose of radiation at low doses and low dose rates, nor by an underestimate of the relative biological efficiency of high as compared with low linear energy transfer radiation. One possible explanation was underestimation of doses to the red bone marrow due to the discharges at Dounreay relative to the dose from fallout, though investigation of ways in which this might have occurred did not suggest anything definite. Other possible explanations included a misconception of the site of origin of childhood leukaemia, outbreaks of an infectious disease, and exposure to some other, unidentified environmental agent. These findings weigh heavily against the hypothesis that the recent increase in childhood leukaemia near Dounreay might be accounted for by radioactive discharges from nuclear plants, unless the doses to the stem cells from which childhood leukaemia originates have been grossly underestimated. PMID:3103820

Ultrasound-Detected Thyroid Nodule Prevalence and Radiation Dose from Fallout

PubMed Central

Land, C. E.; Zhumadilov, Z.; Gusev, B. I.; Hartshorne, M. H.; Wiest, P. W.; Woodward, P. W.; Crooks, L. A.; Luckyanov, N. K.; Fillmore, C. M.; Carr, Z.; Abisheva, G.; Beck, H. L.; Bouville, A.; Langer, J.; Weinstock, R.; Gordeev, K. I.; Shinkarev, S.; Simon, S. L.

2014-01-01

Settlements near the Semipalatinsk Test Site (SNTS) in northeastern Kazakhstan were exposed to radioactive fallout during 1949–1962. Thyroid disease prevalence among 2994 residents of eight villages was ascertained by ultrasound screening. Malignancy was determined by cytopathology. Individual thyroid doses from external and internal radiation sources were reconstructed from fallout deposition patterns, residential histories and diet, including childhood milk consumption. Point estimates of individual external and internal dose averaged 0.04 Gy (range 0–0.65) and 0.31 Gy (0–9.6), respectively, with a Pearson correlation coefficient of 0.46. Ultrasound-detected thyroid nodule prevalence was 18% and 39% among males and females, respectively. It was significantly and independently associated with both external and internal dose, the main study finding. The estimated relative biological effectiveness of internal compared to external radiation dose was 0.33, with 95% confidence bounds of 0.09–3.11. Prevalence of papillary cancer was 0.9% and was not significantly associated with radiation dose. In terms of excess relative risk per unit dose, our dose–response findings for nodule prevalence are comparable to those from populations exposed to medical X rays and to acute radiation from the Hiroshima and Nagasaki atomic bombings. PMID:18363427

Synimpact-postimpact transition inside Chesapeake Bay crater

USGS Publications Warehouse

Poag, Claude (Wylie)

2002-01-01

The transition from synimpact to postimpact sedimentation inside Chesapeake Bay impact crater began with accumulation of fallout debris, the final synimpact deposit. Evi dence of a synimpact fallout layer at this site comes from the presence of unusual, millimeter- scale, pyrite microstructures at the top of the Exmore crater-fill breccia. The porous geometry of the pyrite microstructures indicates that they originally were part of a more extensive pyrite lattice that encompassed a layer of millimeter-scale glass microspherules—fallout melt particles produced by the bolide impact. Above this microspherule layer is the initial postimpact deposit, a laminated clay-silt-sand unit, 19 cm thick. This laminated unit is a dead zone, which contains abundant stratigraphically mixed and diagenetically altered or impact-altered microfossils (foraminifera, calcareous nannofossils, dinoflagellates, ostracodes), but no evidence of indigenous biota. By extrapolation of sediment- accumulation rates, I estimate that conditions unfavorable to microbiota persisted for as little as <1 k.y. to 10 k.y. after the bolide impact. Subsequently, an abrupt improvement of the late Eocene paleoenvironment allowed species-rich assemblages of foraminifera, ostracodes, dinoflagellates, radiolarians, and calcareous nannoplankton to quickly reoccupy the crater basin, as documented in the first sample of the Chickahominy Formation above the dead zone.

Synimpact-postimpact transition inside Chesapeake Bay crater

USGS Publications Warehouse

Poag, C.W.

2002-01-01

The transition from synimpact to postimpact sedimentation inside Chesapeake Bay impact crater began with accumulation of fallout debris, the final synimpact deposit. Evidence of a synimpact fallout layer at this site comes from the presence of unusual, millimeter-scale, pyrite microstructures at the top of the Exmore crater-fill breccia. The porous geometry of the pyrite microstructures indicates that they originally were part of a more extensive pyrite lattice that encompassed a layer of millimeter-scale glass microspherules-fallout melt particles produced by the bolide impact. Above this microspherule layer is the initial postimpact deposit, a laminated clay-silt-sand unit, 19 cm thick. This laminated unit is a dead zone, which contains abundant stratigraphically mixed and diagenetically altered or impact-altered microfossils (foraminifera, calcareous nannofossils, dinoflagellates, ostracodes), but no evidence of indigenous biota. By extrapolation of sediment-accumulation rates, I estimate that conditions unfavorable to microbiota persisted for as little as <1 k.y. to 10 k.y. after the bolide impact. Subsequently, an abrupt improvement of the late Eocene paleoenvironment allowed species-rich assemblages of foraminifera, ostracodes, dinoflagellates, radiolarians, and calcareous nannoplankton to quickly reoccupy the crater basin, as documented in the first sample of the Chickahominy Formation above the dead zone.

Contribution of Hanford liquid effluents to strontium-90 levels in offsite soils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jaquish, R.E.

1993-08-01

Strontium-90 is a major constituent of liquid effluents entering the Columbia River at the 100-N Area. The Columbia River also contains {sup 90}Sr from world-wide fallout that enters the Columbia River upstream of Hanford. Irrigation water pumped from the Columbia River can deposit {sup 90}Sr on soil where it can be taken up by farm crops. Fallout has also deposited {sup 90}Sr directly on soil by atmospheric deposition. A review of the sources of {sup 90}Sr in soil in the vicinity of Hanford indicates that about 2% can be attributed to Hanford liquid effluents. PNL measurements of {sup 90}Sr inmore » soil at a background location agree with predicted levels of fallout made by the Federal Radiation Council in 1964. Alfalfa is routinely monitored for {sup 90}Sr and is of special interest since it has concentrations higher than other farm crops. The concentrations of {sup 90}Sr in alfalfa measured in the Hanford vicinity are in the range one would expect, based on measured soil concentrations and using uptake factors from an earlier {sup 90}Sr uptake study at Hanford.« less

An evaluation of the Kearny Fallout Meter (KFM), a radiation detector constructed from commonly available household materials.

PubMed

McDonald, J T; West, W G; Kearfott, K J

2004-11-01

A radiation detector constructed of common household materials was developed at Oak Ridge National Laboratory (ORNL) by Cresson H. Kearny and has been referred to as the Kearny Fallout Meter (KFM). Developed during the height of the Cold War, the KFM was intended to place a radiation meter capable of measuring fallout from nuclear weapons in the hands of every U.S. citizen. Instructions for the construction of the meter, as well as information about radiation health effects, were developed in the form of multi-page newspaper insert. Subsequently, the sensitivity of the meter was refined by a high school teacher, Dr. Paul S. Lombardi, for use in demonstrations about radiation. The meter is currently being marketed for survivalists in light of potential radiation terrorist concerns. The KFM and Lombardi's variation of it are constructed and evaluated for this work. Calibrated tests of the response and variations in response are reported. A critique of the multi-page manual is made. In addition, the suitability of using such a detector, in terms of actual ease of construction and practical sensitivity, is discussed for its use in demonstrations and introductory classes on nuclear topics.

On the distribution and inventories of radionuclides in dated sediments around the Swedish coast.

PubMed

Olszewski, Grzegorz; Andersson, Pål; Lindahl, Patric; Eriksson, Mats

2018-06-01

The activity concentrations and distribution of 137 Cs, 238 Pu, 239+240 Pu, 241 Am, and 210 Pb was determined by the analysis of six sediment cores from the Baltic Sea and Kattegat. The chronology of the sediment cores has been used to evaluate the origin and time trend of the radionuclide sources in these sediments. The sediment cores were dated with a 210 Pb model and the results were validated with fallout peaks, assumed to originate from the global nuclear weapons testing and the Chernobyl accident. Source identification, using the isotopic and radionuclide activity ratios, showed that the Chernobyl accident is the main source of 137 Cs in the Baltic Sea; for 239+240 Pu and 241 Am the dominant source was shown to be fallout from nuclear weapons tests. For 238 Pu and 241 Am the Chernobyl accident had a significant impact on the direct fallout into the Baltic Proper, with up to a 65% contribution in the sediment slices dated to 1986. In these sediment slices the maximum activity ratios of 238 Pu/ 239+240 Pu and 241 Am/ 239+240 Pu were 0.314 ± 0.008 and 1.29 ± 0.06, respectively. The ratios clearly deviate from the corresponding ratios for global nuclear weapons fallout (around 0.028 and 0.54, respectively). Calculated inventories were 63-175 Bq·m -2 for 239+240 Pu, 2.8-7.8 for 238 Pu Bq·m -2 and 0.92-44.4 kBq·m -2 for 137 Cs. Different fallout patterns for 137 Cs and plutonium isotopes from the Chernobyl accident were confirmed through depth profiles analyses. The maximum inventory of 137 Cs was observed in the Bothnian Sea, while Chernobyl-derived plutonium was found to be mostly present in Northern Baltic Proper. The radionuclides distribution in the depth profiles shows how contaminated water affects the sediment as it passes sampling stations according to the current circulation pattern in the Baltic Sea. Additionally, the effect of increased activity concentrations from of river discharges in the most contaminated area in the Bothnian Sea was observed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Estimate of tephra accumulation probabilities for the U.S. Department of Energy's Hanford Site, Washington

USGS Publications Warehouse

Hoblitt, Richard P.; Scott, William E.

2011-01-01

In response to a request from the U.S. Department of Energy, we estimate the thickness of tephra accumulation that has an annual probability of 1 in 10,000 of being equaled or exceeded at the Hanford Site in south-central Washington State, where a project to build the Tank Waste Treatment and Immobilization Plant is underway. We follow the methodology of a 1987 probabilistic assessment of tephra accumulation in the Pacific Northwest. For a given thickness of tephra, we calculate the product of three probabilities: (1) the annual probability of an eruption producing 0.1 km3 (bulk volume) or more of tephra, (2) the probability that the wind will be blowing toward the Hanford Site, and (3) the probability that tephra accumulations will equal or exceed the given thickness at a given distance. Mount St. Helens, which lies about 200 km upwind from the Hanford Site, has been the most prolific source of tephra fallout among Cascade volcanoes in the recent geologic past and its annual eruption probability based on this record (0.008) dominates assessment of future tephra falls at the site. The probability that the prevailing wind blows toward Hanford from Mount St. Helens is 0.180. We estimate exceedance probabilities of various thicknesses of tephra fallout from an analysis of 14 eruptions of the size expectable from Mount St. Helens and for which we have measurements of tephra fallout at 200 km. The result is that the estimated thickness of tephra accumulation that has an annual probability of 1 in 10,000 of being equaled or exceeded is about 10 centimeters. It is likely that this thickness is a maximum estimate because we used conservative estimates of eruption and wind probabilities and because the 14 deposits we used probably provide an over-estimate. The use of deposits in this analysis that were mostly compacted by the time they were studied and measured implies that the bulk density of the tephra fallout we consider here is in the range of 1,000-1,250 kg/m3. The load of 10 cm of such tephra fallout on a flat surface would therefore be in the range of 100-125 kg/m2; addition of water from rainfall or snowmelt would provide additional load.

Plutonium activities and 240Pu/ 239Pu atom ratios in sediment cores from the east China sea and Okinawa Trough: Sources and inventories

NASA Astrophysics Data System (ADS)

Wang, Zhong-liang; Yamada, Masatoshi

2005-05-01

Plutonium concentrations and 240Pu/ 239Pu atom ratios in the East China Sea and Okinawa Trough sediment cores were determined by isotope dilution inductively coupled plasma mass spectrometry after separation using ion-exchange chromatography. The results showed that 240Pu/ 239Pu atom ratios in the East China Sea and Okinawa Trough sediments, ranging from 0.21 to 0.33, were much higher than the reported value of global fallout (0.18). The highest 240Pu/ 239Pu ratios (0.32-0.33) were observed in the deepest Okinawa Trough sediment samples. These ratios suggested the US nuclear weapons tests in the early 1950s at the Pacific Proving Grounds in the Marshall Islands were a major source of plutonium in the East China Sea and Okinawa Trough sediments, in addition to the global fallout source. It was proposed that close-in fallout plutonium was delivered from the Pacific Proving Grounds test sites via early direct tropospheric fallout and transportation by the North Pacific Equatorial Circulation system and Kuroshio Current into the Okinawa Trough and East China Sea. The total 239 + 240 Pu inventories in the cores were about 150-200% of that expected from direct global fallout; about 46-67% of the total inventories were delivered from the Pacific Proving Grounds. Much higher 239 + 240 Pu inventories were observed in the East China Sea sediments than in sediments of the Okinawa Trough, because in the open oceans, part of the 239 + 240 Pu was still retained in the water column, and continued Pu scavenging was higher over the margin than the trough. According to the vertical distributions of 239 + 240 Pu activities and 240Pu/ 239Pu atom ratios in these cores, it was concluded that sediment mixing was the dominant process in controlling profiles of plutonium in this area. Faster mixing in the coastal samples has homogenized the entire 240Pu/ 239Pu ratio record today; slightly slower mixing and less scavenging in the Okinawa Trough have left the surface sediment ratios closer to the modern North Pacific water end member and higher ratios (0.30-0.34) at the bottom of the cores.

Can 239 + 240Pu replace 137Cs as an erosion tracer in agricultural landscapes contaminated with Chernobyl fallout?

PubMed

Schimmack, W; Auerswald, K; Bunzl, K

2001-01-01

Erosion studies often use 137Cs from the global fallout (main period: 1953-1964) as a tracer in the soil. In many European countries, where 137Cs was deposited in considerable amounts also by the Chernobyl fallout in 1986, the global fallout fraction (GF-Cs) has to be separated from the Chernobyl fraction by means of the isotope 134Cs. In a few years, this will no longer be possible due to the short half-life of 134Cs (2 yr). Because GF-Cs in the soil can then no longer be determined, the potential of using 239 + 240Pu as a tracer is evaluated. This radionuclide originates in most European countries essentially only from the global fallout. The activities and spatial distributions of Pu and GF-Cs were compared in the soil of a steep field (inclination about 20%, area ca. 3 ha, main soil type Dystric Eutrochrept), sampled at 48 nodes of a 25 x 25 m2 grid. The reference values were determined at 12 points adjacent to the field. Their validity was assured by an inventory study of radiocaesium in a 70 ha area surrounding the field sampling 275 nodes of a 50 x 50 m2 grid. In the field studied, the activity concentrations of GF-Cs and Pu in the Ap horizon were not correlated (Spearman correlation coefficient R = 0.20, p > 0.05), and the activity balance of Pu differed from that of GF-Cs. Whereas no net loss of GF-Cs from the field was observed as compared to the reference site, Pu was more mobile with an average loss of ca. 11% per unit area. In addition, the spatial pattern of GF-Cs and Pu in the field differed significantly. The reason may be that due to their different associations with soil constituents, Pu and Cs represent different fractions of the soil, exhibiting different properties with respect to erosion/deposition processes. This indicates that both radionuclides or one of them may not be appropriate to quantity past erosion. When tracer losses are used to calibrate or verify erosion prediction models, systematic deviations may not only stem from model shortcomings but also from tracer technique.

On-the-fly Doppler broadening of unresolved resonance region cross sections

DOE PAGES

Walsh, Jonathan A.; Forget, Benoit; Smith, Kord S.; ...

2017-07-29

In this paper, two methods for computing temperature-dependent unresolved resonance region cross sections on-the-fly within continuous-energy Monte Carlo neutron transport simulations are presented. The first method calculates Doppler broadened cross sections directly from zero-temperature average resonance parameters. In a simulation, at each event that requires cross section values, a realization of unresolved resonance parameters is generated about the desired energy and temperature-dependent single-level Breit-Wigner resonance cross sections are computed directly via the analytical Ψ-x Doppler integrals. The second method relies on the generation of equiprobable cross section magnitude bands on an energy-temperature mesh. Within a simulation, the bands are sampledmore » and interpolated in energy and temperature to obtain cross section values on-the-fly. Both of the methods, as well as their underlying calculation procedures, are verified numerically in extensive code-to-code comparisons. Energy-dependent pointwise cross sections calculated with the newly-implemented procedures are shown to be in excellent agreement with those calculated by a widely-used nuclear data processing code. Relative differences at or below 0.1% are observed. Integral criticality benchmark results computed with the proposed methods are shown to reproduce those computed with a state-of-the-art processed nuclear data library very well. In simulations of fast spectrum systems which are highly-sensitive to the representation of cross section data in the unresolved region, k-eigenvalue and neutron flux spectra differences of <10 pcm and <1.0% are observed, respectively. The direct method is demonstrated to be well-suited to the calculation of reference solutions — against which results obtained with a discretized representation may be assessed — as a result of its treatment of the energy, temperature, and cross section magnitude variables as continuous. Also, because there is no pre-processed data to store (only temperature-independent average resonance parameters) the direct method is very memory-efficient. Typically, only a few kB of memory are needed to store all required unresolved region data for a single nuclide. However, depending on the details of a particular simulation, performing URR cross section calculations on-the-fly can significantly increase simulation times. Alternatively, the method of interpolating equiprobable probability bands is demonstrated to produce results that are as accurate as the direct reference solutions, to within arbitrary precision, with high computational efficiency in terms of memory requirements and simulation time. Analyses of a fast spectrum system show that interpolation on a coarse energy-temperature mesh can be used to reproduce reference k-eigenvalue results obtained with cross sections calculated continuously in energy and directly at an exact temperature to within <10 pcm. Probability band data on a mesh encompassing the range of temperatures relevant to reactor analysis usually require around 100 kB of memory per nuclide. Finally, relative to the case in which probability table data generated at a single, desired temperature are used, minor increases in simulation times are observed when probability band interpolation is employed.« less

Assessment of dry and wet atmospheric deposits of radioactive aerosols: application to Fukushima radiocaesium fallout.

PubMed

Gonze, Marc-André; Renaud, Philippe; Korsakissok, Irène; Kato, Hiroaki; Hinton, Thomas G; Mourlon, Christophe; Simon-Cornu, Marie

2014-10-07

The Fukushima Dai-ichi nuclear accident led to massive atmospheric deposition of radioactive substances onto the land surfaces. The spatial distribution of deposits has been estimated by Japanese authorities for gamma-emitting radionuclides through either airborne monitoring surveys (since April 2011) or in situ gamma-ray spectrometry of bare soil areas (since summer 2011). We demonstrate that significant differences exist between the two surveys for radiocaesium isotopes and that these differences can be related to dry deposits through the use of physically based relationships involving aerosol deposition velocities. The methodology, which has been applied to cesium-134 and cesium-137 deposits within 80-km of the nuclear site, provides reasonable spatial estimations of dry and wet deposits that are discussed and compared to atmospheric numerical simulations from the Japanese Atomic Energy Agency and the French Institute of Radioprotection and Nuclear Safety. As a complementary approach to numerical simulations, this field-based analysis has the possibility to contribute information that can be applied to the understanding and assessment of dose impacts to human populations and the environment around Fukushima.

Nuclear Data Sheets for A=37

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cameron J.; Nica N.; Cameron,J.

2012-02-01

Nuclear spectroscopic information for experimentally investigated nuclides of mass 37 (Na, Mg, Al, Si, P, S, Cl, Ar, K, Ca) has been evaluated. The principal sources of the 'adopted levels' presented for nuclides close to the stability line are Endt's evaluations (1990En08, 1978En02). The data sets for reactions and decays, including all available gamma-ray data, are based mostly on the original literature. There are no data available for the excited states in {sup 37}Na, {sup 37}Mg, {sup 37}Al; and for {sup 37}Si, only one excited state is known.

Dependence of nuclear quadrupole resonance transitions on the electric field gradient asymmetry parameter for nuclides with half-integer spins

DOE PAGES

Cho, Herman

2016-02-28

Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with I = 3/2,5/2,7/2, and 9/2. These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Furthermore, applications of NQR methods to studies of electronic structure in heavy element systems are proposed.

Evaluated nuclear structure data file

NASA Astrophysics Data System (ADS)

Tuli, J. K.

1996-02-01

The Evaluated Nuclear Structure Data File (ENSDF) contains the evaluated nuclear properties of all known nuclides, as derived both from nuclear reaction and radioactive decay measurements. All experimental data are evaluated to create the adopted properties for each nuclide. ENSDF, together with other numeric and bibliographic files, can be accessed on-line through the INTERNET or modem, and some of the databases are also available on the World Wide Web. The structure and the scope of ENSDF are presented along with the on-line access system of the National Nuclear Data Center at Brookhaven National Laboratory.

Evaluated nuclear structure data file

NASA Astrophysics Data System (ADS)

Tuli, J. K.

The Evaluated Nuclear Structure Data File (ENSDF) contains the evaluated nuclear properties of all known nuclides. These properties are derived both from nuclear reaction and radioactive decay measurements. All experimental data are evaluated to create the adopted properties for each nuclide. ENSDF, together with other numeric and biographic files, can be accessed on-line through the INTERNET or modem. Some of the databases are also available on the World Wide Web. The structure and the scope of ENSDF are presented along with the on-line access system of the National Nuclear Data Center at Brookhaven National Laboratory.

Cosmogenic radionuclides

NASA Astrophysics Data System (ADS)

Cosmic rays interact with the earth's atmosphere and surface to produce the “cosmogenic” nuclides. In many instances the radioactive ones are readily distinguished from the anthropogenic and meteoritic backgrounds. Measurements of these cosmogenic radionuclides (RCN) can contribute to the solution of a variety of geophysical problems [Lai and Peters, 1967]. Recent progress in this area was discussed at a symposium entitled Application of Cosmic-Ray-Produced Nuclides in Geophysics held May 30, 1983, at the AGU Spring Meeting in Baltimore (see Eos, May 3, 1983, pp. 282-284, for the abstracts). We summarize here the symposium presentations.

Interactive Chart of Nuclides

Science.gov Websites

Chart of Nuclides Click on a nucleus for information Color code Half-life Decay Mode Qβ- QEC QÎ Radiation Help - Glossary This site is better seen using the latest version of internet browsers. Database ²+ Sn Sp Qα S2n S2p Q2β- Q2EC QECp Qβ-n BE/A (BE-LDM Fit)/A E1st ex. st. E2+ E3- E4+ E4+/E2+ β2 B(E2

Evaluation of Ruthenium Capture Methods for Tritium Pretreatment Off-Gas Streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spencer, Barry B.; Jubin, Robert Thomas; Bruffey, Stephanie H.

2017-07-01

In the reprocessing of used nuclear fuel, radioactive elements are released into various plant off-gas streams. While much research and development has focused on the abatement of the volatile nuclides 3H, 14C, 85Kr, and 129I, the potential release of semivolatile isotopes that could also report to the off-gas streams in a reprocessing facility has been examined. Ruthenium (as 106Ru) has been identified as one of the semivolatile nuclides requiring the greatest degree of abatement prior to discharging the plant off-gas to the environment.

Instrumental activation analysis of coal and fly ash with thermal and epithermal neutrons and short-lived nuclides

USGS Publications Warehouse

Steinnes, E.; Rowe, J.J.

1976-01-01

Instrumental neutron activation analysis is applied to the determination of about 25 elements in coals and fly ash by means of nuclides with half-lives of less than 48 h ; thermal and epithermal irradiations are used. The results indicate that epithermal activation is preferable for twelve of the elements (Ga, As, Br, Sr, In, Cs, Ba, La, Sm, Ho, W and U). Data for SRM 1632 (coal) and SRM 1633 (fly ash) compare favorably with the results obtained by other investigators. ?? 1976.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rick Demmer; John Drake; Ryan James, PhD

Over the last 50 years, the study of radiological contamination and decontamination has expanded significantly. This paper addresses the mechanisms of radiological contamination that have been reported and then discusses which methods have recently been used during performance testing of several different decontamination technologies. About twenty years ago the Idaho Nuclear Technology Engineering Center (INTEC) at the INL began a search for decontamination processes which could minimize secondary waste. In order to test the effectiveness of these decontamination technologies, a new simulated contamination, termed SIMCON, was developed. SIMCON was designed to replicate the types of contamination found on stainless steel,more » spent fuel processing equipment. Ten years later, the INL began research into methods for simulating urban contamination resulting from a radiological dispersal device (RDD). This work was sponsored by the Defense Advanced Research Projects Agency (DARPA) and included the initial development an aqueous application of contaminant to substrate. Since 2007, research sponsored by the US Environmental Protection Agency (EPA) has advanced that effort and led to the development of a contamination method that simulates particulate fallout from an Improvised Nuclear Device (IND). The IND method diverges from previous efforts to create tenacious contamination by simulating a reproducible “loose” contamination. Examining these different types of contamination (and subsequent decontamination processes), which have included several different radionuclides and substrates, sheds light on contamination processes that occur throughout the nuclear industry and in the urban environment.« less

Early precambrian asteroid impact-triggered tsunami: excavated seabed, debris flows, exotic boulders, and turbulence features associated with 3.47-2.47 Ga-old asteroid impact fallout units, Pilbara Craton, Western Australia.

PubMed

Glikson, Andrew Y

2004-01-01

Pioneering studies of Precambrian impact fallout units and associated tsunami deposits in the Hamersley Basin, Pilbara Craton, Western Australia, by B.M. Simonson and S.W. Hassler, document a range of tsunami deposits associated with impact fallout units whose impact connection is identified by associated microtektites and microkrystites (condensation spherules). The impact connection of these particles is demonstrated by iridium anomalies, unique platinum group elements patterns, and Ni-rich mineral phases. Densely packed tsunami-transported fragments and boulders overlie microkrystite units of the >2629 +/- 5 Ma top Jeerinah Impact Layer (JIL). Tsunami events closely follow spherule settling associated with the 2561 +/- 8 Ma Spherule Marker Bed SMB-1 and SMB-2 impact events, Bee Gorge Member, Wittenoom Formation. The two impact cycles are separated by a stratigraphically consistent silicified black siltstone, representing a "Quiet Interval." The SMB turbidites display turbulence eddies, climbing ripples, conglomerate pockets, slumps, and waterlogged sediment deformation features. Consequences of tsunami in the probably contemporaneous Carawine Dolomite (Pb-Pb carbonate ages of approximately 2.56-2.54 Ga), eastern Hamersley Basin, include sub-autochthonous below-wave base excavation and megabrecciation of sea floor substrata, resulting in a unique 10-30-m-thick spherule-bearing megabreccia marker mapped over a nearly 100-km north-south strike distance in the east Hamersley Basin. The field relations suggest a pretsunami settling of the bulk of the spherules. Tsunami wave effects include: (1). dispersal of the spherule-rich soft upper sea floor sediments as a subaqueous mud cloud and (2). excavation of consolidated substrata below the soft sediment zone. Excavation and megabrecciation included injection of liquefied spherule-bearing microbreccia into dilated fractures in the disrupted underlying carbonates. Near-perfect preservation of the spherules within the basal microbreccia veins suggests tsunami-induced hydraulic pressures locally exceeded lithostatic pressure. Late-stage settling of spherule-bearing mud clouds in the wake of the tsunami is represented by an abundance of spherules in the uppermost microbreccia zones of the megabreccia pile. From the deep below-wave base facies of the Carawine Dolomite, tsunami wave amplitudes may have exceeded 200 m depth. The approximately 2.47-2.50 Ga DGS4 (S4 Macroband, Dales Gorge Member, Brockman Iron Formation) fallout units include exotic chert and carbonate boulders transported by tsunami following settling of a 10-20-cm-thick microkrystite and microtektite-rich unit. Seismic perturbations preceding deposition of the JIL and SMB fallout units are marked by rip-up clasts. The geochemistry of microkrystites and microtektites suggests impact fallout originated from impacts in simatic/oceanic crustal regions, although tsunami waves may have originated from seismically reactivated faults and plate margins located at distance from the impact craters.

Do cosmogenic nuclides (10Be, 14C , 21Ne, 26Al) track late Quaternary climate changes on the Altiplano?

NASA Astrophysics Data System (ADS)

Hippe, K.; Kober, F.; Zeilinger, G.; Ivy-Ochs, S.; Kubik, P.; Maden, C.; Wieler, R.

2010-12-01

The high Altiplano plateau is the most prominent element of the Central Andes, separating the Andean Cordilleras between 15° to 22° S. It represents a tectonically quiet, intramontane basin with arid to semi-arid climate, low relief and internal drainage. Throughout the late Quaternary regional climate on the Altiplano repeatedly changed between wet and dry conditions [1]. The influence of climate on the plateau evolution during the Pleistocene/Holocene is unclear, however, as data on erosion processes and rates on the Altiplano are sparse. Here, we present a multiple-nuclide study investigating surface denudation at the eastern Altiplano of Bolivia (16°-17° S) on millennial and longer timescales. The aim is a better understanding of the complex feedback between climate, tectonics and geomorphology on the topographic evolution of the Andes. Catchment-wide denudation (CWD) rates are provided for a 150 km NW-SE transect along the Altiplano edge based on the analyses of cosmogenic 10Be, 26Al, 21Ne and in-situ 14C in river-borne sediment. Single nuclide CWD rates obtained for 10Be, 26Al and 21Ne are similar for all three nuclides and on the order of 3-37 mm/ka. Thus, the calculated denudation rates provide an averaged denudation history dating back at least to the middle Pleistocene. Denudation rates correlate positively with the mean basin hillslope, which is mainly controlled by basin lithology. For most catchments both, the 26Al/10Be ratios and the 21Ne/10Be ratios indicate a complex erosion/exposure history with probably several periods of sediment storage and burial/shielding totalling ~0.5 - 1.2 Ma. Local geomorphology featuring low slopes and low relief, small terraces and local floodplains also suggests that sediment transport might have been periodically ineffective. Concentrations of in-situ produced short-lived 14C are significantly lower than expected from the concentrations of the long-lived and stable cosmogenic nuclides. This would indicate a 30-40 fold increase in denudation rates since ~3000 years, which appears rather unlikely. Hence, the measured in-situ 14C concentrations may actually reflect sediment storage. Partial sediment shielding at ~80-150 cm depth is plausible from field evidence. Due to the fast decay of 14C, such shielding would result in a drop of the 14C concentration from saturation to the measured values already after several 1000 years. Nevertheless, other explanations as incomplete sediment mixing also have to be taken into account. Interestingly, our CWD long-term data agree well with short-term sediment yield data from the Altiplano (5.6-48 mm/ka) [2]. This suggests an overall uniformity in erosional processes and rates throughout the late Quaternary. The agreement between single nuclide denudation rates, despite the complex storage history, also argues for rather long-term steady-state conditions and highlights the insensitivity of long-lived cosmogenic nuclides to low amplitude, short-term variations in climate. References: [1] Plazcek et al. (2006), GSA Bulletin 118, 515-532, [2] Guyot et al. (1992), Lake Titicaca 113-119.

Constraining Quaternary ice covers and erosion rates using cosmogenic 26Al/10Be nuclide concentrations

NASA Astrophysics Data System (ADS)

Knudsen, Mads Faurschou; Egholm, David Lundbek

2018-02-01

Paired cosmogenic nuclides are often used to constrain the exposure/burial history of landforms repeatedly covered by ice during the Quaternary, including tors, high-elevation surfaces, and steep alpine summits in the circum-Arctic regions. The approach generally exploits the different production rates and half-lives of 10Be and 26Al to infer past exposure/burial histories. However, the two-stage minimum-limiting exposure and burial model regularly used to interpret the nuclides ignores the effect of variable erosion rates, which potentially may bias the interpretation. In this study, we use a Monte Carlo model approach to investigate systematically how the exposure/burial and erosion history, including variable erosion and the timing of erosion events, influence concentrations of 10Be and 26Al. The results show that low 26Al/10Be ratios are not uniquely associated with prolonged burial under ice, but may as well reflect ice covers that were limited to the coldest part of the late Pleistocene combined with recent exhumation of the sample, e.g. due to glacial plucking during the last glacial period. As an example, we simulate published 26Al/10Be data from Svalbard and show that it is possible that the steep alpine summits experienced ice-free conditions during large parts of the late Pleistocene and varying amounts of glacial erosion. This scenario, which contrasts with the original interpretation of more-or-less continuous burial under non-erosive ice over the last ∼1 Myr, thus challenge the conventional interpretation of such data. On the other hand, high 26Al/10Be ratios do not necessarily reflect limited burial under ice, which is the common interpretation of high ratios. In fact, high 26Al/10Be ratios may also reflect extensive burial under ice, combined with a change from burial under erosive ice, which brought the sample close to the surface, to burial under non-erosive ice at some point during the mid-Pleistocene. Importantly, by allowing for variable erosion rates, the model results may reconcile spatially varying 26Al/10Be data from bedrock surfaces preserved over multiple glacial cycles, suggesting that samples from the same high-elevation surface or neighbouring alpine summits may have experienced similar long-term burial under ice, but varying amounts of glacial erosion.

Beam-on imaging of short-lived positron emitters during proton therapy

NASA Astrophysics Data System (ADS)

Buitenhuis, H. J. T.; Diblen, F.; Brzezinski, K. W.; Brandenburg, S.; Dendooven, P.

2017-06-01

In vivo dose delivery verification in proton therapy can be performed by positron emission tomography (PET) of the positron-emitting nuclei produced by the proton beam in the patient. A PET scanner installed in the treatment position of a proton therapy facility that takes data with the beam on will see very short-lived nuclides as well as longer-lived nuclides. The most important short-lived nuclide for proton therapy is 12N (Dendooven et al 2015 Phys. Med. Biol. 60 8923-47), which has a half-life of 11 ms. The results of a proof-of-principle experiment of beam-on PET imaging of short-lived 12N nuclei are presented. The Philips Digital Photon Counting Module TEK PET system was used, which is based on LYSO scintillators mounted on digital SiPM photosensors. A 90 MeV proton beam from the cyclotron at KVI-CART was used to investigate the energy and time spectra of PET coincidences during beam-on. Events coinciding with proton bunches, such as prompt gamma rays, were removed from the data via an anti-coincidence filter with the cyclotron RF. The resulting energy spectrum allowed good identification of the 511 keV PET counts during beam-on. A method was developed to subtract the long-lived background from the 12N image by introducing a beam-off period into the cyclotron beam time structure. We measured 2D images and 1D profiles of the 12N distribution. A range shift of 5 mm was measured as 6  ±  3 mm using the 12N profile. A larger, more efficient, PET system with a higher data throughput capability will allow beam-on 12N PET imaging of single spots in the distal layer of an irradiation with an increased signal-to-background ratio and thus better accuracy. A simulation shows that a large dual panel scanner, which images a single spot directly after it is delivered, can measure a 5 mm range shift with millimeter accuracy: 5.5  ±  1.1 mm for 1  ×  108 protons and 5.2  ±  0.5 mm for 5  ×  108 protons. This makes fast and accurate feedback on the dose delivery during treatment possible.

Notre Dame Nuclear Database: A New Chart of Nuclides

NASA Astrophysics Data System (ADS)

Lee, Kevin; Khouw, Timothy; Fasano, Patrick; Mumpower, Matthew; Aprahamian, Ani

2014-09-01

Nuclear data is critical to research fields from medicine to astrophysics. We are creating a database, the Notre Dame Nuclear Database, which can store theoretical and experimental datasets. We place emphasis on storing metadata and user interaction with the database. Users are able to search in addition to the specific nuclear datum, the author(s), the facility where the measurements were made, the institution of the facility, and device or method/technique used. We also allow users to interact with the database by providing online search, an interactive nuclide chart, and a command line interface. The nuclide chart is a more descriptive version of the periodic table that can be used to visualize nuclear properties such as half-lives and mass. We achieve this by using D3 (Data Driven Documents), HTML, and CSS3 to plot the nuclides and color them accordingly. Search capabilities can be applied dynamically to the chart by using Python to communicate with MySQL, allowing for customization. Users can save the customized chart they create to any image format. These features provide a unique approach for researchers to interface with nuclear data. We report on the current progress of this project and will present a working demo that highlights each aspect of the aforementioned features. This is the first time that all available technologies are put to use to make nuclear data more accessible than ever before in a manner that is much easier and fully detailed. This is a first and we will make it available as open source ware.

Associated-particle sealed-tube neutron probe for nonintrusive inspection

NASA Astrophysics Data System (ADS)

Rhodes, E.; Dickerman, C. E.

1997-02-01

The development and investigation of a small associated-particle sealed-tube neutron generator (APSTNG) show potential for the associated-particle method to move out of the laboratory into field applications. This paper is a review of ANL investigations of this technology. Alpha particles associated with 14-MeV neutrons generated from the D-T reaction travel in the opposite direction and are detected inside the sealed tube. Gamma-ray spectra of resulting neutron reactions in the inspected volume encompassed by the alpha-detector solid angle identify many nuclides. Flight-times determined from detection times of the gamma rays and alpha particles separate the prompt and delayed gamma-rays and can yield a separate coarse tomographic image of each identified nuclide, from a single orientation without collimation. A continuous ion beam allows data acquisition by relatively low-bandwidth electronics. When a compact sealed-tube neutron generator is used, a relatively small and easily maintainable inspection system can be developed, that is rugged enough to be transportable. Proof-of-concept laboratory experiments have been performed for simulated explosives, drugs, special nuclear materials, and chemical warfare agents. Efficient collection of maximum information from each detected neutron with low background rates can allow a much lower source intensity than pulsed accelerator methods and yield a preference for an APSTNG system, when it can provide adequate usable source intensity. Based on lessons learned with the present system, an advanced APSTNG system is being designed and built that will be transportable and yield substantial increases in neutron output and target lifetime.

ActiWiz 3 – an overview of the latest developments and their application

NASA Astrophysics Data System (ADS)

Vincke, H.; Theis, C.

2018-06-01

In 2011 the ActiWiz code was developed at CERN in order to optimize the choice of materials for accelerator equipment from a radiological point of view. Since then the code has been extended to allow for calculating complete nuclide inventories and provide evaluations with respect to radiotoxicity, inhalation doses, etc. Until now the software included only pre-defined radiation environments for CERN’s high-energy proton accelerators which were based on FLUKA Monte Carlo calculations. Eventually the decision was taken to invest into a major revamping of the code. Starting with version 3 the software is not limited anymore to pre-defined radiation fields but within a few seconds it can also treat arbitrary environments of which fluence spectra are available. This has become possible due to the use of ~100 CPU years’ worth of FLUKA Monte Carlo simulations as well as the JEFF cross-section library for neutrons < 20 MeV. Eventually the latest code version allowed for the efficient inclusion of 42 additional radiation environments of the LHC experiments as well as considerably more flexibility in view of characterizing also waste from CERN’s Large Electron Positron collider (LEP). New fully integrated analysis functionalities like automatic evaluation of difficult-to-measure nuclides, rapid assessment of the temporal evolution of quantities like radiotoxicity or dose-rates, etc. make the software a powerful tool for characterization complementary to general purpose MC codes like FLUKA. In this paper an overview of the capabilities will be given using recent examples from the domain of waste characterization as well as operational radiation protection.

Modeling estimates of the effect of acid rain on background radiation dose.

PubMed Central

Sheppard, S C; Sheppard, M I

1988-01-01

Acid rain causes accelerated mobilization of many materials in soils. Natural and anthropogenic radionuclides, especially 226Ra and 137Cs, are among these materials. Okamoto is apparently the only researcher to date who has attempted to quantify the effect of acid rain on the "background" radiation dose to man. He estimated an increase in dose by a factor of 1.3 following a decrease in soil pH of 1 unit. We reviewed literature that described the effects of changes in pH on mobility and plant uptake of Ra and Cs. Generally, a decrease in soil pH by 1 unit will increase mobility and plant uptake by factors of 2 to 7. Thus, Okamoto's dose estimate may be too low. We applied several simulation models to confirm Okamoto's ideas, with most emphasis on an atmospherically driven soil model that predicts water and nuclide flow through a soil profile. We modeled a typical, acid-rain sensitive soil using meteorological data from Geraldton, Ontario. The results, within the range of effects on the soil expected from acidification, showed essentially direct proportionality between the mobility of the nuclides and dose. This supports some of the assumptions invoked by Okamoto. We conclude that a decrease in pH of 1 unit may increase the mobility of Ra and Cs by a factor of 2 or more. Our models predict that this will lead to similar increases in plant uptake and radiological dose to man. Although health effects following such a small increase in dose have not been statistically demonstrated, any increase in dose is probably undesirable. PMID:3203639

Modelling the relationship between zooplankton biomass and environmental variations in the distribution of 210Po during a one year cycle in northwestern Mediterranean coastal waters.

PubMed

Färber Lorda, Jaime; Tateda, Yutaka; Fowler, Scott W

2017-08-01

To clarify the relationship between zooplankton biomass and the environmental kinetics of the natural radionuclide 210 Po during a one-year period (October 1995 to November 1996) in northwestern Mediterranean coastal waters, a modelling analysis was applied. Using 210 Po concentrations in seawater and zooplankton, the 210 Po uptake rate constant from food for zooplankton was evaluated using a biokinetics calculation involving the uptake and the excretion rate constants between seawater and zooplankton. Using the transfer constants obtained, the 210 Po concentrations in zooplankton were reconstructed and validated by observed concentrations. The simulation results were in good agreement with the measured 210 Po concentrations in zooplankton. Assuming that 210 Po fecal excretion represents the majority of the excretion of 210 Po from zooplankton, the fecal matter associated 210 Po vertical flux was calculated, and compared with the observed vertical fluxes of 210 Po measured in sediment traps. The modelling evaluation showed that fecal pellet vertical transport could not fully explain the observed sinking fluxes of particulate organic matter at 150 m depth, suggesting that other sinking biodetrital aggregates are also important components of the plankton-derived vertical flux of 210 Po. The relationship between 210 Po concentration in seawater and that in rain and dry fallout and their potential effect on 210 Po concentrations in zooplankton at this location were also examined. A similar, but diphased trend between 210 Po in zooplankton and 210 Po in rain and dry fallout deposition rate was demonstrated. 210 Po concentrations in the dissolved phase of seawater tended to diminish as mean daily rainfall increased suggesting that rain inputs serve as a 210 Po dilution mechanism in seawater at this location. Copyright © 2016 Elsevier Ltd. All rights reserved.

CIELO Collaboration Summary Results: International Evaluations of Neutron Reactions on Uranium, Plutonium, Iron, Oxygen and Hydrogen

DOE PAGES

Chadwick, M. B.; Capote, R.; Trkov, A.; ...

2018-03-07

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies - 235,238U, 239Pu, 56Fe, 16O and 1H - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality. This report summarizes our results on cross sectionsmore » and preliminary work on covariances, and outlines plans for the next phase of this collaboration.« less