Download or read book Criticality Safety Considerations in the Geologic Disposal of Spent Nuclear Fuel Assemblies written by B. F. Gore and published by . This book was released on 1980 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Criticality Safety Considerations in the Geologic Disposal of Spent Nuclear Fuel Assemblies written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Safety and Security of Commercial Spent Nuclear Fuel Storage written by National Research Council and published by National Academies Press. This book was released on 2006-02-19 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: In response to a request from Congress, the Nuclear Regulatory Commission and the Department of Homeland Security sponsored a National Academies study to assess the safety and security risks of spent nuclear fuel stored in cooling pools and dry casks at commercial nuclear power plants. The information provided in this book examines the risks of terrorist attacks using these materials for a radiological dispersal device. Safety and Security of Commercial Spent Nuclear Fuel is an unclassified public summary of a more detailed classified book. The book finds that successful terrorist attacks on spent fuel pools, though difficult, are possible. A propagating fire in a pool could release large amounts of radioactive material, but rearranging spent fuel in the pool during storage and providing emergency water spray systems would reduce the likelihood of a propagating fire even under severe damage conditions. The book suggests that additional studies are needed to better understand these risks. Although dry casks have advantages over cooling pools, pools are necessary at all operating nuclear power plants to store at least the recently discharged fuel. The book explains it would be difficult for terrorists to steal enough spent fuel to construct a significant radiological dispersal device.

Download or read book Criticality Safety Study for the Disposal of Spent Nuclear Fuel in Water Saturated Geologic Repository written by Xudong Liu and published by . This book was released on 2016 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Damaged fuels originated from the accident at the Fukushima-Daiichi Nuclear Power Station, and the spent nuclear fuels from commercial light water reactors (LWRs) in Japan are considered to be disposed of in deep geological repository. For a prospective repository, as part of generic performance assessment, a criticality safety assessment (CSA) should be performed to ensure that the repository system including the engineered barriers and host geological formations remains sub-critical for tens of thousands to millions of years. For various repository concepts, CSA is considered to include three major stages in chronological order: (1) the stage before package failure, (2) the stage after package failure, while fissile nuclides remain within the engineered barrier system (EBS) and in the near-field region, and (3) the stage in which fissile nuclides originated from multiple packages are deposited in far-field host rocks. Defining the model for neutronics calculations plays a central role in CSAs, where conservative assumptions are usually made to cope with various uncertainties and to simplify the model. The aim of this dissertation is to develop neutronics models for different stages in the criticality safety study, and provide basic understandings for the long-term criticality safety for the disposal of spent nuclear fuel in geologic repository. In the near-field analysis, a neutronics model has been developed for a system consisting of a canister containing fuel debris from Fukushima reactors and the surrounding buffer, in a water-saturated deep geological repository. The fuel debris has been modeled as a hexagonal lattice of spherical fuel particles. Following key observations have been concluded from the numerical results: (a) the calculated neutron multiplicity (keff) is sensitively dependent on assumptions related to moderation, (b) the carbon steel canister plays an important role in reducing the potential for criticality, (c) the maximum keff of the canister-buffer system could be achieved after a fraction of fissile nuclides been released from the canister, and (d) under several assumptions, the maximum keff of the canister-buffer system could be principally determined by the dimension and composition of the canister, not by the initial fuel loading. Based on the preliminary results and findings, a parametric study has been made to identify the optimized lattice parameters for criticality. And the critical mass of damaged fuels for a single canister has been calculated. If this critical mass is used as the maximum canister mass loadings, roughly a thousand canisters are needed to contain the damaged fuels from the three damaged cores. For the LWR spent fuels, a parametric study has been performed to examine spent fuels with different designs and burnup histories. The numerical results indicate that, under the conditions assumed, for all UO2 spent fuels and most of the MOX spent fuels, the single canister model will always be subcritical. The far-field study has been focusing on neutronic analysis to examine the criticality conditions for uranium depositions in geological formations which result from geological disposal of damaged fuels from Fukushima reactors. Neutronics models are used to evaluate the keff and critical mass for various combinations of host rock and geometries. The present study has revealed that the planar fracture geometry applied in the previous criticality safety assessment for geological disposal would not necessarily yield conservative results against the homogeneous uranium deposition. It has been found that various far-field critical configurations are conceivable for given conditions of materials and geological formations. Prior to knowing the site location, some important points for selecting a site for criticality safety can be suggested. These include: (a) iron existing in the host rock reduces the likelihood of criticality significantly; (b) low host rock porosity is preferred for criticality safety; (c) the conservatism could change when comparing heterogeneous geometries for different fracture apertures; and (d) the importance of the mass of the deposition increases when it is smaller. As part of the improvement for the models developed in the far-field analysis, preliminary works on uranium depositions in randomly fractured rocks have been presented. The randomly fractured geometry could fundamentally influence the far-field criticality, because the system's keff value sensitively depends on the fracture aperture and the depositions at fracture intersections. No previous work has been made to study the effect of random geometry in the context of the long-term criticality safety in a geologic repository. Different numerical schemes have been developed and compared for the direct sampling of uranium depositions in randomly fractured rocks using MCNP. A general literature review of existing methods for neutron transport problems with random processes has been made. And the analytical Feinberg-Galanin-Horning (FGH) method has been derived and tested for a numerical example.

Download or read book Criticality Safety Issues Associated with the Burial of Highly Enriched Nuclear Fuel in a Geologic Repository written by and published by . This book was released on 1992 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this study is to provide some basic guidance regarding the criticality safety implications associated with long term burial of highly enriched nuclear fuel in a geologic repository. Generic calculations to determine the distance required to neutronically isolate neighboring fissile regions are reported. Two specific fuels are also addressed, Fort Saint Vrain and Shippingport PWR Core-2 Seed-2 (PWR). These fuels are addressed under both dry and flooded conditions. Fort Saint Vrain fuel contains a uranium-graphite fuel matrix, is graphite moderated and has a relatively low 235U loading (∼1 kg per element). PWR contains a uranium-zirconium fuel matrix, is water moderated, zircaloy clad and has a 235U loading of ∼15 kg per cluster. These two fuels are representative of many of the fuels currently stored at the Idaho Chemical Processing Plant (ICPP). The spent fuel storage system under consideration involves filling cylindrical canisters with spent nuclear fuel. These canisters are then to be placed into a geologic repository. Salt and tuff are the two most likely materials in which the canisters will be buried. Canisters will require sufficient material between them to ensure that the overall reactivity stays within acceptable limits. Fuels will also have to be shown to be critically safe under a variety of conditions. These conditions include flooding and the loss of the physical integrity of the fuel.

Download or read book Criticality Safety Issues Associated with the Burial of Highly Enriched Nuclear Fuel in a Geologic Repository written by B. Palmer and published by . This book was released on 1992 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Disposal of Spent Nuclear Fuel written by and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report addresses the topic of the mined geologic disposal of spent nuclear fuel from Pressurized Water Reactors (PWR) and Boiling Water Reactors (BWR). Although some fuel processing options are identified, most of the information in this report relates to the isolation of spent fuel in the form it is removed from the reactor. The characteristics of the waste management system and research which relate to spent fuel isolation are discussed. The differences between spent fuel and processed HLW which impact the waste isolation system are defined and evaluated for the nature and extent of that impact. What is known and what needs to be determined about spent fuel as a waste form to design a viable waste isolation system is presented. Other waste forms and programs such as geologic exploration, site characterization and licensing which are generic to all waste forms are also discussed. R and D is being carried out to establish the technical information to develop the methods used for disposal of spent fuel. All evidence to date indicates that there is no reason, based on safety considerations, that spent fuel should not be disposed of as a waste.

Download or read book Safeguards Issues Relevant to Geologic Disposal of Spent Nuclear Fuels written by and published by . This book was released on 1989 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: In civilian nuclear fuel cycles, the time between removal of spent nuclear fuels from reactors and the final stages of nuclear waste disposal spans several decades. Safeguarding nuclear materials contained in spent fuels during this period varies with (1) storage modes, (2) packaging and transportation requirements, and (3) treatment of spent fuel for consolidation or recovery of fissile elements. This paper considers some possible diversion scenarios of spent nuclear fuels and identifies actions necessary to evaluate the needs of a comprehensive safeguards system to assure both domestic and international safeguards. 4 refs.

Download or read book The Los Alamos Primer written by Robert Serber and published by . This book was released on 2020 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: More than seventy years ago, American forces exploded the first atomic bombs over the Japanese cities of Hiroshima and Nagasaki, causing great physical and human destruction. The young scientists at Los Alamos who developed the bombs, which were nicknamed Little Boy and Fat Man, were introduced to the basic principles and goals of the project in March 1943, at a crash course in new weapons technology. The lecturer was physicist Robert Serber, J. Robert Oppenheimer's protégé, and the scientists learned that their job was to design and build the world's first atomic bombs. Notes on Serber's lectures were gathered into a mimeographed document titled TheLos Alamos Primer, which was supplied to all incoming scientific staff. The Primer remained classified for decades after the war. Published for the first time in 1992, the Primer offers contemporary readers a better understanding of the origins of nuclear weapons. Serber's preface vividly conveys the mingled excitement, uncertainty, and intensity felt by the Manhattan Project scientists. This edition includes an updated introduction by Pulitzer Prize-winning historian Richard Rhodes. A seminal publication on a turning point in human history, The Los Alamos Primer reveals just how much was known and how terrifyingly much was unknown midway through the Manhattan Project. No other seminar anywhere has had greater historical consequences.

Download or read book Disposition of High Level Radioactive Waste Through Geological Isolation written by National Research Council and published by National Academies Press. This book was released on 1999-10-07 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the next several years, decisions are expected to be made in several countries on the further development and implementation of the geological disposition option. The Board on Radioactive Waste Management (BRWM) of the U.S. National Academies believes that informed and reasoned discussion of relevant scientific, engineering and social issues can-and should-play a constructive role in the decision process by providing information to decision makers on relevant technical and policy issues. A BRWM-initiated project including a workshop at Irvine, California on November 4-5, 1999, and subsequent National Academies' report to be published in spring, 2000, are intended to provide such information to national policy makers both in the U.S. and abroad. To inform national policies, it is essential that experts from the physical, geological, and engineering sciences, and experts from the policy and social science communities work together. Some national programs have involved social science and policy experts from the beginning, while other programs have only recently recognized the importance of this collaboration. An important goal of the November workshop is to facilitate dialogue between these communities, as well as to encourage the sharing of experiences from many national programs. The workshop steering committee has prepared this discussion for participants at the workshop. It should elicit critical comments and help identify topics requiring in-depth discussion at the workshop. It is not intended as a statement of findings, conclusions, or recommendations. It is rather intended as a vehicle for stimulating dialogue among the workshop participants. Out of that dialogue will emerge the findings, conclusions, and recommendations of the National Academies' report.

Download or read book Nuclear Criticality Safety Analysis of a Spent Fuel Waste Package in a Tuff Repository written by and published by . This book was released on 1983 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: An assessment has been performed of the criticality potential associated with the disposal of spent fuel in a tuff geology above the water table. Eleven potential configurations were defined which cover a vast range of geometries and conditions from the nominal configuration at emplacement to a hypothetical configuration thousands of years after emplacement in which the structure is gone, the fuel pellets disintegrated and the borehole flooded. Of these eleven configurations, four have been evaluated at this time. The results of this evaluation indicate that even with very conservative assumptions (4.5 w/o fresh fuel), criticality is not a problem for the nominal configuration either dry or fully flooded. In the cases where the condition of the waste package is assumed to have severely deteriorated, over long times, calculations were performed with less conservative assumptions (depleted fuel). An assessment of these calculations indicates that criticality safety could be demonstrated if the depletion of the fissile inventory during fuel irradiation is taken into account. A detailed discussion of the calculations performed is presented in this report. Also included are a description of the configurations which were considered, the analytical methods and models used, and a discussion of additional related work which should be performed. 15 references, 11 figures, 8 tables.

Download or read book Nuclear Criticality Safety Analysis of a Spent Fuel Waste Package in a Tuff Repository written by B. H. Weren and published by . This book was released on 1983 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: An assessment has been performed of the criticality potential associated with the disposal of spent fuel in a tuff geology above the water table. Eleven potential configurations were defined which cover a vast range of geometries and conditions from the nominal configuration at emplacement to a hypothetical configuration thousands of years after emplacement in which the structure is gone, the fuel pellets disintegrated and the borehole flooded. Of these eleven configurations, four have been evaluated at this time. The results of this evaluation indicate that even with very conservative assumptions (4.5 w/o fresh fuel), criticality is not a problem for the nominal configuration either dry or fully flooded. In the cases where the condition of the waste package is assumed to have severely deteriorated, over long times, calculations were performed with less conservative assumptions (depleted fuel). An assessment of these calculations indicates that criticality safety could be demonstrated if the depletion of the fissile inventory during fuel irradiation is taken into account. A detailed discussion of the calculations performed is presented in this report. Also included are a description of the configurations which were considered, the analytical methods and models used, and a discussion of additional related work which should be performed.

Download or read book Advances in High Temperature Gas Cooled Reactor Fuel Technology written by International Atomic Energy Agency and published by . This book was released on 2012-06 with total page 639 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication reports on the results of a coordinated research project on advances in high temperature gas cooled reactor (HTGR) fuel technology and describes the findings of research activities on coated particle developments. These comprise two specific benchmark exercises with the application of HTGR fuel performance and fission product release codes, which helped compare the quality and validity of the computer models against experimental data. The project participants also examined techniques for fuel characterization and advanced quality assessment/quality control. The key exercise included a round-robin experimental study on the measurements of fuel kernel and particle coating properties of recent Korean, South African and US coated particle productions applying the respective qualification measures of each participating Member State. The summary report documents the results and conclusions achieved by the project and underlines the added value to contemporary knowledge on HTGR fuel.

Download or read book Handling and Final Storage of Unreprocessed Spent Nuclear Fuel Technical written by and published by . This book was released on 1978 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Storage of Spent Nuclear Fuel written by International Atomic Energy Agency and published by . This book was released on 2021-04-30 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication is a revision by amendment of IAEA Safety Standards Series No. SSG-15 and provides recommendations and guidance on the storage of spent nuclear fuel. It covers all types of storage facility and all types of spent fuel from nuclear power plants and research reactors. It takes into consideration the longer storage periods beyond the original design lifetime of the storage facility that have become necessary owing to delays in the development of disposal facilities and the reduction in reprocessing activities. It also considers developments associated with nuclear fuel, such as higher enrichment, mixed oxide fuels and higher burnup. Guidance is provided on all stages in the lifetime of a spent fuel storage facility, from planning through siting and design to operation and decommissioning. The revision was undertaken by amending, adding and/or deleting specific paragraphs addressing recommendations and findings from studying the accident at the Fukushima Daiichi nuclear power plant in Japan.

Download or read book Spent Nuclear Fuel as a Waste Form for Geologic Disposal written by and published by . This book was released on 1987 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study assesses the status of knowledge pertinent to evaluating the behavior of spent nuclear fuel as a waste form in geologic disposal systems and provides background information that can be used by the DOE to address the information needs that pertain to compliance with applicable standards and regulations. To achieve this objective, applicable federal regulations were reviewed, expected disposal environments were described, the status of spent-fuel modeling was summarized, and information regarding the characteristics and behavior of spent fuel was compiled. This compiled information was then evaluated from a performance modeling perspective to identify further information needs. A number of recommendations were made concerning information still needed to enhance understanding of spent-fuel behavior as a waste form in geologic repositories. 335 refs., 22 figs., 44 tabs.

Download or read book Assessment of the Impacts of Spent Fuel Disassembly Alternatives on the Nuclear Waste Isolation System Preparing and Packaging Spent Fuel Assemblies for Geologic Disposal written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this report was to evaluate four possible alternative methods of preparing and packaging spent fuel assemblies for geologic disposal against the Reference Process of unmodified spent fuel. The four alternative processes were: (1) End fitting removal, (2) Fission gas venting and resealing, (3) Fuel bundle disassembly and close packing of fuel pins, and (4) Fuel shearing and immobilization. Systems analysis was used to develop a basis of comparison of the alternatives. Conceptual processes and facility layouts were devised for each of the alternatives, based on technology deemed feasible for the purpose. Assessments were made of 15 principal attributes from the technical, operational, safety/risk, and economic considerations related to each of the alternatives, including both the surface packaging and underground repository operations. Specific attributes of the alternative processes were evaluated by assigning a number for each that expressed its merit relative to the corresponding attribute of the Reference Process. Each alternative process was then ranked by summing the numbers for attributes in each of the four assessment areas and collectively. Fuel bundle disassembly and close packing of fuel pins was ranked the preferred method of disposal of spent fuel. 63 references, 46 figures, 46 tables.