Download or read book Nuclear Data for Criticality Safety Current Issues written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Data Needs for Application in Nuclear Criticality Safety Programs written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The National Criticality Data Center written by and published by . This book was released on 1967 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Data Advisory Group Technical Support for the US Nuclear Criticality Safety Program written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Integration of Several Elements of the DOE Nuclear Criticality Safety Program written by and published by . This book was released on 2001 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. Department of Energy established the Nuclear Criticality Safety Program (NCSP) to maintain the infrastructure and expertise in nuclear criticality safety to support line criticality safety programs at various DOE sites. The seven tasks of the NCSP include critical experiments, benchmarking, nuclear data, analytical methods, applicable ranges of bounding curves and data, information preservation and dissemination, and training and qualification. The goals of this program are to improve the knowledge, tools, data, guidance, and information available to the nuclear criticality safety community. In addition various elements of the NCSP are integrated together to provide the nuclear criticality safety community with the most precise nuclear data for criticality safety analyses. This paper describes how several elements of the NCSP were integrated together in the evaluation of the silicon nuclear data. Silicon is frequently encountered in decontamination and decommissioning efforts, process sludge and settling tanks, in situ vitrification, and waste remediation efforts (including waste storage, retrieval, characterization, volume reduction, and stabilization). Silicon was also identified as an important isotope for addressing concerns associated with the storage of spent nuclear fuels in a geologic repository. The inadequacy of the silicon nuclear data in the intermediate energy region mandated that additional neutron capture cross-section measurements had to be performed that encompassed the resolved resonance region. An evaluation was performed that included analysis of the most recent neutron capture and existing transmission cross-section measurements performed at the Oak Ridge Electron Linear Accelerator. Critical experiments were performed at the Institute of Physics and Power Engineering in Obninsk, Russia because of the lack of critical experiment data for analysis of storage of nuclear material in a geologic repository. These critical experiments were evaluated and benchmark models were developed and submitted to the International Criticality Safety Benchmark Evaluation Project for review and publication in the ''International Handbook of Evaluated Criticality Safety Benchmark Experiments''. Sensitivity analyses were performed as a part of the benchmark evaluation to determine the sensitivity of the critical experiments to the various constituents of the assembly. The benchmark models were then used to determine the computed k{sub eff} for various cross section data sets. The variation in the computed k{sub eff} value for the new evaluated data set was then used as an indicator to adjust the negative energy capture widths for the capture cross section data. Furthermore, the changes in k{sub eff} were used as an indicator to the inadequacy of previous measured data in the unresolved resonance region. The result of the efforts of the NCSP provided the most precise set of nuclear data for silicon. The resulting ORNL evaluation produced the most consistent evaluation for silicon. This result could only be achieved through integration of many components of the NCSP.
Download or read book Nuclear Criticality Safety written by Ronald Allen Knief and published by American Nuclear Society. This book was released on 1985 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear criticality safety is the prevention of nuclear chain reactions in fissile materials outside of reactors. This book presents the underlying principles of nuclear criticality safety theory along with descriptions of the principal methods currently used and their in-plant applications. Exercises are provided at the end of each chapter to increase understanding of the text.
Download or read book Recueil factice d articles de presse concernant Gontier written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Criticality Safety Handbook Version 2 written by Nihon Genshiryoku Kenkyūjo. Working Group on Nuclear Criticality Safety Data and published by . This book was released on 2001 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization Strategy Report for the Criticality Safety Issue written by and published by . This book was released on 1997 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-level radioactive waste from nuclear fuels processing is stored in underground waste storage tanks located in the tank farms on the Hanford Site. Waste in tank storage contains low concentrations of fissile isotopes, primarily U-235 and Pu-239. The composition and the distribution of the waste components within the storage environment is highly complex and not subject to easy investigation. An important safety concern is the preclusion of a self-sustaining neutron chain reaction, also known as a nuclear criticality. A thorough technical evaluation of processes, phenomena, and conditions is required to make sure that subcriticality will be ensured for both current and future tank operations. Subcriticality limits must be based on considerations of tank processes and take into account all chemical and geometrical phenomena that are occurring in the tanks. The important chemical and physical phenomena are those capable of influencing the mixing of fissile material and neutron absorbers such that the degree of subcriticality could be adversely impacted. This report describes a logical approach to resolving the criticality safety issues in the Hanford waste tanks. The approach uses a structured logic diagram (SLD) to identify the characterization needed to quantify risk. The scope of this section of the report is limited to those branches of logic needed to quantify the risk associated with a criticality event occurring. The process is linked to a conceptual model that depicts key modes of failure which are linked to the SLD. Data that are needed include adequate knowledge of the chemical and geometric form of the materials of interest. This information is used to determine how much energy the waste would release in the various domains of the tank, the toxicity of the region associated with a criticality event, and the probability of the initiating criticality event.
Download or read book DOE Spent Nuclear Fuel Nuclear Criticality Safety Challenges and Safeguards Initiatives written by and published by . This book was released on 1994 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of nuclear criticality safety is confronted with growing technical challenges and the need for forward-thinking initiatives to address and resolve issues surrounding economic, safe and secure packaging, transport, interim storage, and long-term disposal of spent nuclear fuel. These challenges are reflected in multiparameter problems involving optimization of packaging designs for maximizing the density of material per package while ensuring subcriticality and safety under variable normal and hypothetical transport and storage conditions and for minimizing costs. Historic and recently revealed uncertainties in basic data used for performing nuclear subcriticality evaluations and safety analyses highlight the need to be vigilant in assessing the validity and range of applicability of calculational evaluations that represent extrapolations from ''benchmark'' data. Examples of these uncertainties are provided. Additionally, uncertainties resulting from the safeguarding of various forms of fissionable materials in transit and storage are discussed.
Download or read book Validation of Criticality Safety Calculations with SCALE 6 2 written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: SCALE 6.2 provides numerous updates in nuclear data, nuclear data processing, and computational tools utilized in the criticality safety calculational sequences relative to SCALE 6.1. A new 252-group ENDF/B-VII.0 multigroup neutron library, improved ENDF/B-VII.0 continuous energy data, as well as the previously deployed 238-group ENDF/B-VII.0 neutron library are included in SCALE 6.2 for criticality safety analysis. The performance of all three libraries for keff calculations is examined with a broad sampling of critical experiment models covering a range of fuels and moderators. Critical experiments from the International Handbook of Evaluated Criticality Safety Benchmark Experiments (IHECSBE) that are available in the SCALE Verified, Archived Library of Inputs and Data (VALID) are used in this validation effort. Over 300 cases are used in the validation of KENO V.a, and a more limited set of approximately 50 configurations are used for KENO-VI validation. Additionally, some KENO V.a cases are converted to KENO-VI models so that an equivalent set of experiments can be used to validate both codes. For continuous-energy calculations, SCALE 6.2 provides improved performance relative to SCALE 6.1 in most areas with notable improvements in fuel pin lattice cases, particularly those with mixed oxide fuel. Multigroup calculations with the 252-group library also demonstrate improved performance for fuel lattices, uranium (high and intermediate enrichment) and plutonium metal experiments, and plutonium solution systems. Overall, SCALE 6.2 provides equivalent or smaller biases than SCALE 6.1, and the two versions of KENO provide similar results on the same suite of problems.
Download or read book NUREG CR written by U.S. Nuclear Regulatory Commission and published by . This book was released on 1977 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Criticality Project Plan for the Hanford Site Tank Farms written by and published by . This book was released on 1996 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mission of this project is to provide a defensible technical basis report in support of the Final Safety Analysis Report (FSAR). This technical basis report will also be used to resolve technical issues associated with the nuclear criticality safety issue. The strategy presented in this project plan includes an integrated programmatic and organizational approach. The scope of this project plan includes the provision of a criticality technical basis supporting document (CTBSD) to support the FSAR as well as for resolution of the nuclear criticality safety issue. Specifically, the CTBSD provides the requisite technical analysis to support the FSAR hazard and accident analysis as well as for the determination of the required FSAR limits and controls. The scope of The CTBSD will provide a baseline for understanding waste partitioning and distribution phenomena and mechanistics for current operational activities inclusive of single-shell tanks, double-shell tanks, double-contained receiver tanks, and miscellaneous underground storage tanks. Although the FSAR does not include future operational activities, the waste partitioning and distribution phenomena and mechanistics work scope identified in this project plan provide a sound technical basis as a point of departure to support independent safety analyses for future activities. The CTBSD also provides the technical basis for resolution of the technical issues associated with the nuclear criticality safety issue. In addition to the CTBSD, additional documentation will be required to fully resolve U.S. Department of Energy-Headquarters administrative and programmatic issues. The strategy and activities defined in this project plan provide a CTBSD for the FSAR and for accelerated resolution of the safety issue in FY 1996. On April 30, 1992, a plant review committee reviewed the Final Safety Analysis Reports for the single-shell, double-shell, and aging waste tanks in light of the conclusions of the inadequate waste characterization with respect to fissile material. The review indicated that the conclusion in the FSARS, that a criticality is not credible, cannot be supported for a full range of potential tank constituents. Therefore, a USQ was declared. Development of a credible scenario leading to a criticality proved to be extremely difficult, given the paucity of data on the quantity and distribution of fissile material in the tanks. The objective of this project plan is to develop a strategy and technical approach to provide a CTBSD for the FSAR and for resolution of the nuclear criticality safety issue pertaining to tank farm waste storage and transfer operations. The strategy and technical approach identified in this project plan include definition of administrative and technical tasks. Technical analyses will include mechanistic studies, historical data review, and additional limited neutronics analysis. Completion of these studies will be documented in a CTBSD to support the existing criticality technical basis. The CTBSD will be incorporated in the criticality portion of the FSAR.
Download or read book Nuclear Criticality Safety Data Book written by and published by . This book was released on 2016 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this document is to support the revision of criticality safety process studies (CSPSs) for the Uranium Processing Facility (UPF) at the Y-12 National Security Complex (Y-12). This design analysis and calculation (DAC) document contains development and justification for generic inputs typically used in Nuclear Criticality Safety (NCS) DACs to model both normal and abnormal conditions of processes at UPF to support CSPSs. This will provide consistency between NCS DACs and efficiency in preparation and review of DACs, as frequently used data are provided in one reference source.
Download or read book Nuclear Criticality Safety written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Merger of Nuclear Data with Criticality Safety Calculations written by and published by . This book was released on 1999 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper we report on current activities related to the merger of differential/integral data (especially in the resolved-resonance region) with nuclear criticality safety computations. Techniques are outlined for closer coupling of many processes measurement, data reduction, differential-data analysis, integral-data analysis, generating multigroup cross sections, data-testing, criticality computations which in the past have been treated independently.
Download or read book Nuclear Safety written by and published by . This book was released on 1994 with total page 762 pages. Available in PDF, EPUB and Kindle. Book excerpt:
