127,823 research outputs found

    Study of Minor Actinides Transmutation in PWR MOX fuel

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    The management of long-lived radionuclides in spent fuel is a key issue to achieve the closed nuclear fuel cycle and the sustainable development of nuclear energy. Partitioning-Transmutation is supposed to be an efficient method to treat the long-lived radionuclides in spent fuel. Some Minor Actinides (MAs) have very long half-lives among the radionuclides in the spent fuel. Accordingly, the study of MAs transmutation is a significant work for the post-processing of spent fuel. In the present work, the transmutations in Pressurized Water Reactor (PWR) mixed oxide (MOX) fuel are investigated through the Monte Carlo based code RMC. Two kinds of MAs, 237^{237}Np and five MAs (237^{237}Np, 241^{241}Am, 243^{243}Am, 244^{244}Cm and 245^{245}Cm) are incorporated homogeneously into the MOX fuel assembly. The transmutation of MAs is simulated with different initial MOX concentrations. The results indicate an overall nice efficiency of transmutation in both initial MOX concentrations, especially for the two kinds of MAs primarily generated in the UOX fuel, 237^{237}Np and 241^{241}Am. In addition, the inclusion of 237^{237}Np in MOX has no large influence for other MAs, while the transmutation efficiency of 237^{237}Np is excellent. The transmutation of MAs in MOX fuel depletion is expected to be a new, efficient nuclear spent fuel management method for the future nuclear power generation

    Determining Reactor Flux from Xenon-136 and Cesium-135 in Spent Fuel

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    The ability to infer the reactor flux from spent fuel or seized fissile material would enhance the tools of nuclear forensics and nuclear nonproliferation significantly. We show that reactor flux can be inferred from the ratios of xenon-136 to xenon-134 and cesium-135 to cesium-137. If the average flux of a reactor is known, the flux inferred from measurements of spent fuel could help determine whether that spent fuel was loaded as a blanket or close to the mid-plane of the reactor. The cesium ratio also provides information on reactor shutdowns during the irradiation of fuel, which could prove valuable for identifying the reactor in question through comparisons with satellite reactor heat monitoring data. We derive analytic expressions for these correlations and compare them to experimental data and to detailed reactor burn simulations. The enrichment of the original uranium fuel affects the correlations by up to 3 percent, but only at high flux.Comment: 10 pages, 9 figure

    China's Spent Nuclear Fuel Management: Current Practices and Future Strategies

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    Although China’s nuclear power industry is relatively young and the management of its spent nuclear fuel is not yet a concern, China’s commitment to nuclear energy and its rapid pace of development require detailed analyses of its future spent fuel management policies. The purpose of this study is to provide an overview of China’s fuel cycle program and its reprocessing policy, and to suggest strategies for managing its future fuel cycle program. The study is broken into four sections. The first reviews China’s current nuclear fuel cycle program and facilities. The second discusses China’s current spent fuel management methods and the storage capability of China’s 13 operational nuclear power plants. The third estimates China’s total cumulated spent fuel, its required spent fuel storage from present day until 2035, when China expects its first commercialized fast neutron reactors to be operational, and its likely demand for uranium resources. The fourth examines several spent fuel management scenarios for the present period up until 2035; the financial cost and proliferation risk of each scenario is evaluated. The study concludes that China can and should maintain a reprocessing operation to meet its R&D activities before its fast reactor program is further developed

    Nuclear Fuel Cycle: Safe Management of Spent Nuclear Fuel

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    The aim for storage of spent nuclear fuel (SNF) either in wet or in dry storage systems is to ensure general safety objectives are met throughout a desired storage period. Staff at the Savannah River National Laboratory (SRNL), in collaborations with partners at other national laboratories, industry research organizations, and the University of South Carolina (UofSC), have performed materials aging testing and analyses, and have established nuclear materials aging management programs to support extended periods of safe storage of research reactor (RR) SNF and of commercial power reactor (PR) SNF pending ultimate disposal. Several example challenges include susceptibility of aluminum SNF from research reactors to corrosion in poor quality water (wet storage). In dry storage, aluminum SNF can release hydrogen via radiolysis of the hydrated oxides on the aluminum cladding. Austenitic stainless steel canisters used for dry storage are susceptible to chloride-induced stress corrosion cracking (outside-in attack) that threaten the confinement boundary provided by the canister. This paper further describes these challenges, among others, and the formulated solutions to support extended safe storage of SNF

    Novel muon imaging techniques

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    Owing to the high penetrating power of high-energy cosmic ray muons, muon imaging techniques can be used to image large bulky objects, especially objects with heavy shielding. Muon imaging systems work just like CT scanners in the medical imaging field—that is, they can reveal information inside of a target. There are two forms of muon imaging techniques: muon absorption imaging and muon multiple scattering imaging. The former is based on the flux attenuation of muons, and the latter is based on the multiple scattering of muons in matter. The muon absorption imaging technique is capable of imaging very large objects such as volcanoes and large buildings, and also smaller objects like spent fuel casks; the muon multiple scattering imaging technique is best suited to inspect smaller objects such as nuclear waste containers. Muon imaging techniques can be applied in a broad variety of fields, i.e. from measuring the magma thickness of volcanoes to searching for secret cavities in pyramids, and from monitoring the borders of countries checking for special nuclear materials to monitoring the spent fuel casks for nuclear safeguards applications. In this paper, the principles of muon imaging are reviewed. Image reconstruction algorithms such as Filtered Back Projection and Maximum Likelihood Expectation Maximization are discussed. The capability of muon imaging techniques is demonstrated through a Geant4 simulation study for imaging a nuclear spent fuel cask

    Maritime security and nuclear cargoes

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    Civilian nuclear operations entail the transportation of sometimes substantial quantities of radioactive material. These can range from large quantities of weakly radioactive fresh fuel for power reactors, with the corresponding removal of highly radioactive spent fuel and operational wastes, to the shipment of small quantities of radioactive isotopes (“sources”) for medical, industrial or research purposes and their subsequent disposal. In relation to the civilian nuclear fuel cycle, there may also be relatively large quantities of radioactive material produced by “back-end” activities, such as the reprocessing of spent fuel to recover plutonium and then create mixed oxide, or MOX, fuel.1 In between these extremes, there are occasional consignments of fresh and spent fuel to and from research reactors, together with the associated wastes. In many of these cases, circumstances will dictate that consignments are dispatched overland, or by air, but there are some cases where a substantial maritime component is entailed and where there will be particular security and safety concerns that arise from that. Traditionally, the focus of this concern has been on the possibility of accidents, which might result in environmental contamination or human harm, but more recently, and certainly since 11 September 2001, the locus of concern has somewhat shifted to risks that might arise from the activities of non-state armed groups, or terrorists (or even pirates). This is the focus of the present review

    Risk communication between experts and the public: perceptions and intentions

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    This paper develops a conceptual and theoretical analysis of risk communication in cases where experts and the public have widely divergent views of the dimensions of a risk. Applications are chosen from among the risk management problems that are inherent to handling of spent nuclear fuel. One stresses the fact that the conflicting points of views have very different bases. The role of trust is analyzed and, as it is a crucial issue, it becomes much more encompassing than what has usually been assumed. The reasons for this difference can be found in risk perception models applied to survey data concerning risk perception and related attitudes.risk perception; siting; nuclear waste; spent nuclear fuel

    The Classification of Weld Seam Defects for Quantitative Analysis by means of Ultrasonic Testing

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    The paper describes effective quality assessment of spent nuclear fuel storage cask. The ultrasonic testing method is considered. The classification of possible defects with corresponding dimensions limits is proposed. The database of defects of the spent nuclear fuel storage cask was created in compliance with the nuclear energy industry regulatory documents
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