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Category :
Languages : en
Pages : 10
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The potential for the contamination of ground water beneath the Nevada Test Site (NTS) by nuclear testing has long been recognized. The United States has conducted underground nuclear weapons testing at NTS since 1957, and a considerable amount of radioactive material has been deposited in the subsurface by this work. As a part of the U.S. Department of Energy Nevada Operations Office's Underground Test Area Operable Unit (UGTA OP), the Lawrence Livermore National Laboratory (LLNL) has compiled an inventory of radionuclides produced by underground LLNL weapons tests from 1957 through 1992. It is well known that some groundwater at NTS has been contaminated by radionuclides from weapons testing. Nearly one-third of the nuclear tests were conducted near or beneath the pre-test static water level (SWL). An important responsibility of the UGTA OP is to assess the migration potential of contaminants beneath the NTS and surrounding lands. Except for tritium (3H), which is capable of migration with water as molecular HTO, the ability of radionuclides to migrate significant distances from their source is presently thought to be very low. However, before this potential for migration can be fully assessed, the quantity of existing contaminants must be carefully estimated. The inventory of the radionuclide source term provides an upper limit on the availability of radionuclides for migration. However, an accurate assessment of risk to the public depends on more than an inventory of radionuclides remaining from underground testing. An estimate of the hydrologic source term consisting of radionuclides dissolved in or transported by ground water must compliment the radionuclide source term.
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Category :
Languages : en
Pages : 10
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The compilation of a radionuclide inventory for long-lived radioactive contaminants residual from nuclear testing provides a partial measure of the radiologic source term at the Nevada Test Site. The radiologic source term also includes potentially mobile short-lived radionuclides excluded from the inventory. The radiologic source term for tritium is known with accuracy and is equivalent to the hydrologic source term within the saturated zone. Definition of the total hydrologic source term for fission and activation products that have high activities for decades following underground testing involves knowledge and assumptions which are presently unavailable. Systematic investigation of the behavior of fission products, activation products and actinides under saturated or Partially saturated conditions is imperative to define a representative total hydrologic source term. This is particularly important given the heterogeneous distribution of radionuclides within testing centers. Data quality objectives which emphasize a combination of measurements and credible estimates of the hydrologic source term are a priority for near-field investigations at the Nevada Test Site.
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Category :
Languages : en
Pages :
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Frenchman Flat is one of several areas of the Nevada Test Site (NTS) used for underground nuclear testing (Figure 1-1). These nuclear tests resulted in groundwater contamination in the vicinity of the underground test areas. As a result, the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (NNSA/NSO) is currently conducting a corrective action investigation (CAI) of the Frenchman Flat underground test areas. Since 1996, the Nevada Division of Environmental Protection (NDEP) has regulated NNSA/NSO corrective actions through the ''Federal Facility Agreement and Consent Order'' ([FFACO], 1996). Appendix VI of the FFACO agreement, ''Corrective Action Strategy'', was revised on December 7, 2000, and describes the processes that will be used to complete corrective actions, including those in the Underground Test Area (UGTA) Project. The individual locations covered by the agreement are known as corrective action sites (CASs), which are grouped into corrective action units (CAUs). The UGTA CASs are grouped geographically into five CAUs: Frenchman Flat, Central Pahute Mesa, Western Pahute Mesa, Yucca Flat/Climax Mine, and Rainier Mesa/Shoshone Mountain (Figure 1-1). These CAUs have distinctly different contaminant source, geologic, and hydrogeologic characteristics related to their location (FFACO, 1996). The Frenchman Flat CAU consists of 10 CASs located in the northern part of Area 5 and the southern part of Area 11 (Figure 1-1). This report documents the evaluation of the information and data available on the unclassified source term and radionuclide contamination for Frenchman Flat, CAU 98. The methodology used to estimate hydrologic source terms (HSTs) for the Frenchman Flat CAU is also documented. The HST of an underground nuclear test is the portion of the total inventory of radionuclides that is released over time into the groundwater following the test. The total residual inventory of radionuclides associated with one or more tests is known as the radiologic source term (RST). The RST is comprised of radionuclides in water, glass, or other phases or mineralogic forms. This evaluation was conducted in support of the development of a CAU contaminant transport model for the Frenchman Flat CAU.
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Category :
Languages : en
Pages : 15
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It has been proposed that unclassified source terms used in the reactive transport modeling investigations at NTS CAUs should be based on yield-weighted source terms calculated using the average source term from Bowen et al. (2001) and the unclassified announced yields reported in DOE/NV-209. This unclassified inventory is likely to be used in unclassified contaminant boundary calculations and is, thus, relevant to compare to the classified inventory. They have examined the classified radionuclide inventory produced by 10 underground nuclear tests conducted in the Frenchman Flat (FF) area of the Nevada Test Site. The goals were to (1) evaluate the variability in classified radiological source terms among the 10 tests and (2) compare that variability and inventory uncertainties to an average unclassified inventory (e.g. Bowen 2001). To evaluate source term variability among the 10 tests, radiological inventories were compared on two relative scales: geometric mean and yield-weighted geometric mean. Furthermore, radiological inventories were either decay corrected to a common date (9/23/1992) or the time zero (t0) of each test. Thus, a total of four data sets were produced. The date of 9/23/1992 was chosen based on the date of the last underground nuclear test at the Nevada Test Site.
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Category :
Languages : en
Pages :
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This report documents the evaluation of the information and data available on the unclassified source term and radionuclide contamination for CAU 97: Yucca Flat/Climax Mine. The total residual inventory of radionuclides associated with one or more tests is known as the radiologic source term (RST). The RST is comprised of radionuclides in water, glass, or other phases or mineralogic forms. The hydrologic source term (HST) of an underground nuclear test is the portion of the total RST that is released into the groundwater over time following the test. In this report, the HST represents radionuclide release some time after the explosion and does not include the rapidly evolving mechanical, thermal, and chemical processes during the explosion. The CAU 97: Yucca Flat/Climax Mine has many more detonations and a wider variety of settings to consider compared to other CAUs. For instance, the source term analysis and evaluation performed for CAUs 101 and 102: Central and Western Pahute Mesa and CAU 98: Frenchman Flat did not consider vadose zone attenuation because many detonations were located near or below the water table. However, the large number of Yucca Flat/Climax Mine tests and the location of many tests above the water table warrant a more robust analysis of the unsaturated zone. The purpose of this report is to develop and document conceptual models of the Yucca Flat/Climax Mine HST for use in implementing source terms for the Yucca Flat/Climax Mine models. This document presents future plans to incorporate the radionuclide attenuation mechanisms due to unsaturated/multiphase flow and transport within the Yucca Flat CAU scale modeling. The important processes that influence radionuclide migration for the unsaturated and saturated tests in alluvial, volcanic, and carbonate settings are identified. Many different flow and transport models developed by Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL), including original modeling of multiphase flow and transport by the Stoller-Navarro Joint Venture (SNJV), are integrated to form a general understanding of how the RST relates to the HST. This report is unlike the Frenchman Flat source term analysis because it does not calculate the HST for each test. Instead, this work only identifies the important processes that must be considered when the CAU-transport modeling is performed.
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Category : Power resources
Languages : en
Pages : 444
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Category : Science
Languages : en
Pages : 796
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Author: National Research Council
Publisher: National Academies Press
ISBN: 0309096731
Category : Technology & Engineering
Languages : en
Pages : 146
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Underground facilities are used extensively by many nations to conceal and protect strategic military functions and weapons' stockpiles. Because of their depth and hardened status, however, many of these strategic hard and deeply buried targets could only be put at risk by conventional or nuclear earth penetrating weapons (EPW). Recently, an engineering feasibility study, the robust nuclear earth penetrator program, was started by DOE and DOD to determine if a more effective EPW could be designed using major components of existing nuclear weapons. This activity has created some controversy about, among other things, the level of collateral damage that would ensue if such a weapon were used. To help clarify this issue, the Congress, in P.L. 107-314, directed the Secretary of Defense to request from the NRC a study of the anticipated health and environmental effects of nuclear earth-penetrators and other weapons and the effect of both conventional and nuclear weapons against the storage of biological and chemical weapons. This report provides the results of those analyses. Based on detailed numerical calculations, the report presents a series of findings comparing the effectiveness and expected collateral damage of nuclear EPW and surface nuclear weapons under a variety of conditions.
Author: Gerald W. Johnson
Publisher:
ISBN:
Category : Nuclear explosions
Languages : en
Pages : 60
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Author: Vitaly Fedchenko
Publisher: Oxford University Press
ISBN: 0198736649
Category : Political Science
Languages : en
Pages : 310
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Book Description
Nuclear material changes its form and properties as it moves through the nuclear fuel cycle, from one facility to another. Each step of the fuel cycle or each use of the material will inevitably leave its mark. The science of determining the history of a sample of nuclear material through the study of these characteristics is known as nuclear forensics. While nuclear forensic analysis has normally been associated with investigations and prosecutions in the contextof trafficking of nuclear materials or nuclear terrorism, it had wider applications in in national security contexts, such as nuclear non-proliferation, disarmament, and arms control. The New Nuclear Forensics is the first book to give a definitive guide to this broader definition of nuclear forensic analysis. This book describes the various methods used in nuclear forensics, giving first a broad introduction to the process followed by details of relevant measurement techniques and procedures. In each case, the advantages and limitations are outlined. To put these methods in context, the book also recounts the history of the discipline anddescribes the diverse contemporary applications of nuclear forensics.
