29 research outputs found
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ARIES NDA Suite: Fully-integrated and automated nuclear material assay system for measurement of special nuclear materials
The Advanced Retirement and Integrated Extraction System (ARIES) mission the demonstration of advanced technologies for the integrated dismantlement of surplus nuclear weapon components (pits) and the packaging of the recovered plutonium into long-term storage containers. The unclassified plutonium product is suitable for traditional international safeguards, as well as other potential inspection regimes. As indicated in the recent Secretary of Energy`s Record of Decision (ROD), this unclassified excess material is anticipated to be offered for international safeguards under the US Voluntary Offer (INFCIRC/288) performed by the International Atomic Energy Agency (TAEA). The ARIES nondestructive assay (NDA) suite offers state-of-the-art capabilities that provide highly accurate, precise material assay meeting IAEA bias defect measurement levels. Because of these levels of performance, the requirement of destructive analysis is largely removed. The unique combination of automation and high accuracy suggests the possibility of dual-use operator-owned IAEA authenticated instrumentation. Finally, the concept of continuous unattended monitoring for international safeguards applications with the ARIES NDA suite is intriguing and may encourage additional deployments of similar NDA systems internationally or elsewhere within the DOE complex
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SNM measurement uncertainites: potential impacts for materials disposition
A discussion of nuclear material measurement uncertainties and impacts to the Materials Disposition (MD) Program is presented. Many of the options under consideration by the disposition program present new measurement challenges include significant material processing throughputs, a variety of material forms, unique waste streams, and difficult-to-measure matrices. There are also some questions regarding the ability to achieve International Atomic Energy Agency (IAEA) verification requirements and to achieve measurement uncertainties that are small enough to meet the IAEA loss detection goals. We present a detailed formalism for determining the measurement error for nondestructive assay systems applied to the MD Program, which is an essential component for planning the safeguards and security of these systems
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Noble gas atmospheric monitoring at reprocessing facilities
The discovery in Iraq after the Gulf War of the existence of a large clandestine nuclear-weapon program has led to an across-the-board international effort, dubbed Programme 93+2, to improve the effectiveness and efficiency of International Atomic Energy Agency (IAEA) safeguards. One particularly significant potential change is the introduction of environmental monitoring (EM) techniques as an adjunct to traditional safeguards methods. Monitoring of stable noble gas (Kr, Xe) isotopic abundances at reprocessing plant stacks appears to be able to yield information on the burnup and type of the fuel being processed. To estimate the size of these signals, model calculations of the production of stable Kr, Xe nuclides in reactor fuel and the subsequent dilution of these nuclides in the plant stack are carried out for two case studies: reprocessing of PWR fuel with a burnup of 35 GWd/tU, and reprocessing of CAND fuel with a burnup of 1 GWd/tU. For each case, a maximum-likelihood analysis is used to determine the fuel burnup and type from the isotopic data
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Environmental sampling: Issues for the cut-off regime
The fissile material cut-off treaty (FMCT) initiative under the Conference on Disarmament mandate is envisioned to include certain aspects of environmental sampling and monitoring. One of the intents of this treaty is to bring certain non-NPT signatories (e.g., threshold states) under this treaty agreement along with the nuclear weapon states (NWSs). This paper provides a brief overview of some of the relevant issues that may be involved in the implementation and use of environmental monitoring for (1) verification of the cut-off regime declarations, (2) the detection of undeclared activities, and, (3) application in non-routine inspections. The intent is to provide backstopping information important for treaty negotiators. Specific issues addressed within this paper include signature sampling, differences in the proposed detection regime, potential signature integrators, specific examples and spoofing concerns. Many of these issues must be carefully considered and weighed in order to create a credibly verifiable inspection regime. Importantly, the cut-off treaty must enable nondiscriminatory implementation, while carefully assuring that nonproliferation treaty requirements are maintained (i.e., preventing unintentional release of critical weapons design information--potentially through environmental sampling and analysis)
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Nuclear monitoring by nonradioactive noble gas sampling and analysis
This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The perceived importance of measuring the xenon and krypton isotopics of nuclear activities has increased substantially in recent years. We have performed a systems analysis and theoretical simulation of the production, atmospheric dispersion, and isotopic abundances of noble-gas fission products, addressing several questions of interest, including: the relative isotopic variation as a function of nuclear fuel composition, reactor operational history, reactor type, distance from stack, and ambient meteorological conditions. Of particular importance in this analysis was the question of back-calculating process parameters of interest given noble-gas isotopic data. An analysis of the effect of measurement uncertainties was also performed. The results of these analyses indicate that this monitoring concept should be experimentally feasible
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Nonintrusive verification attributes for excess fissile materials
Under US initiatives, over two hundred metric tons of fissile materials have been declared to be excess to national defense needs. These excess materials are in both classified and unclassified forms. The US has expressed the intent to place these materials under international inspections as soon as practicable. To support these commitments, members of the US technical community are examining a variety of nonintrusive approaches (i.e., those that would not reveal classified or sensitive information) for verification of a range of potential declarations for these classified and unclassified materials. The most troublesome and potentially difficult issues involve approaches for international inspection of classified materials. The primary focus of the work to date has been on the measurement of signatures of relevant materials attributes (e.g., element, identification number, isotopic ratios, etc.), especially those related to classified materials and items. The authors are examining potential attributes and related measurement technologies in the context of possible verification approaches. The paper will discuss the current status of these activities, including their development, assessment, and benchmarking status
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High ionization efficiency techniques for CW RIMS
The demand to measure high dynamic range isotope ratios on small samples with RIMS continues to increase. This paper discusses high ionization efficiency methods which can be applied to CW RIMS to potentially achieve several tens of percent ionization efficiencies for certain elements. The primary technique under development to achieve this is an external laser cavity which can generate very high circulating laser powers
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High efficiency resonance ionization mass spectrometric analysis by external laser cavity enhancement techniques
The demand to measure high dynamic range isotope ratios on small samples with resonance ionization mass spectrometry (RIMS) continues to increase. This paper discusses high ionization efficiency methods which can be applied to continuous wave (cw) RIMS to potentially achieve several tens of percent ionization efficiencies for certain elements. The primary technique under development to achieve this is an external laser cavity which can generate very high circulating laser powers. 12 refs., 3 figs
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Comparisons of HELIOS Calculated Isotope Concentrations to Measured Values for Several Reactor Systems
Heavy metal and fission product noble gas concentrations in spent fuel from two different PWR'S were calculated using HELIOS and compared to measured results from the literature. It was found that for the U-235/U-238 and Pu-240/Pu-239 isotopic ratios, the HELIOS calculation agreed to within the experimental uncertainty. For the Xe-131/Xe-134 isotopic ratios, HELIOS tended to overestimate the result by up to 4%. Conversely for the Xe-132/Xe-134 ratios, HELIOS underestimated the result by a slight amount ({approximately}1%). This suggests that either the fission product yields for Xe-131 and Xe-132 should be slightly altered or that the absorption cross-section for Xe-131 should be slightly increased. More analysis is necessary to determine which of these two alternatives is more appropriate. This work has shown that the accuracy of HELIOS (within 2% for heavy metals and within 4% for fission noble gases) is sufficient for most analyses
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Very high resolution saturation spectroscopy of lutetium isotopes via c-w single-frequency laser resonance ionization mass spectrometry
In this paper, we discuss the use of Resonance Ionization Mass Spectrometry (RIMS) to perform isotopically selective saturation spectroscopy of lutetium isotopes. Utilizing this technique, it is shown that accurate measurements of the relative frequencies of hyperfine (HF) components for different isotopes easily can be made without the need for an isotopically enriched sample. The precision with which the HF splitting constants can be determined is estimated to be approx.5 times greater than in previous work