Download or read book Nuclear Criticality Safety Experiments Calculations and Analyses 1958 to 1982 Summaries written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nuclear Criticality Safety Experiments Calculations and Analyses 1958 to 1982 written by Brian L. Koponen and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nuclear Criticality Safety Experiments Calculations and Analyses 1958 to 1982 Volume 2 Summaries Complilation of Papers from the Transactions of the American Nuclear Society written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This compilation contains 688 complete summaries of papers on nuclear criticality safety as presented at meetings of the American Nuclear Society (ANS). The selected papers contain criticality parameters for fissile materials derived from experiments and calculations, as well as criticality safety analyses for fissile material processing, transport, and storage. The compilation was developed as a component of the Nuclear Criticality Information System (NCIS) now under development at the Lawrence Livermore National Laboratory. The compilation is presented in two volumes: Volume 1 contains a directory to the ANS Transaction volume and page number where each summary was originally published, the author concordance, and the subject concordance derived from the keyphrases in titles. Volume 2 contains-in chronological order-the full-text summaries, reproduced here by permission of the American Nuclear Society from their Transactions, volumes 1-41.

Download or read book Nuclear criticality safety experiments calculations and analyses 1958 to 1999 compilation of papers from the Transactions of the American Nuclear Society written by Brian L. Koponen and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Methodology for Determination of the Upper Safety Limit for Criticality Calculations for Criticality Safety Analyses written by and published by . This book was released on 2001 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report considers the methods for determination of an upper safety limit, and incorporating uncertainty and margin into the safety limit, provides comparisons, and recommends a preferred method for determining the Upper Safety Limit (USL). A USL is developed for CSAS25 from SCALE4.4a. The USL is applicable for the CSAS25 control module from the SCALE 4.4a computer code system for use in evaluating nuclear criticality safety of enriched uranium systems. The benchmark calculation results used for this report are documented in Y/DD-896. The statistical evaluation is documented in CCG-380. The 27-group ENDF/B-IV, 44-group ENDF/B-V, and 238-group ENDF/B-V cross-section libraries were used. Numerical methods for applying margins are described, but the determination of appropriate correlating parameters and values for additional margin, applicable to a particular analysis, must be determined as part of a process analysis. As such, this document does not specify final upper subcritical limits as has been done in the past. No correlation between calculation results and neutron energy causing fission was found for the critical experiment results. Analysts using these results are responsible for exercising sound engineering judgment using strong technical arguments to develop ''a margin in k{sub eff} or other correlating parameter that is sufficiently large to ensure that conditions (calculated by this method to be subcritical by this margin) will actually be subcritical.'' Documentation of area of applicability and determination and justification of the appropriate margin in the analyst's evaluation, in conjunction with this report, will constitute the complete Validation Report in accordance with ANSI/ANS-8.1-1998, Section 4.3.6(4).

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 Analysis of Fundamental NIST Sphere Experiments Related to Criticality Safety written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of neutron transport experiments was performed in 1989 and 1990 at NIST (National Institute of Standards and Technology) using a spherical stainless steel container and fission chambers. These experiments were performed to help understand errors observed in criticality calculations for arrays of individually subcritical components, particularly solution arrays [1-3]. They were supported by the U.S. Department of Energy, Environment and Health, Nuclear Criticality Technology and Safety Project. The intent was to evaluate the possibility that the criticality prediction errors stem from errors in the calculation of neutron leakage from individual components of the array. Thus, the explicit product of the experiments was the measurement of the leakage flux, as characterized by various Cd-shielded and unshielded fission rates. Because the various fission rates have different neutron-energy sensitivities, collectively they give an indication of the energy dependence of the leakage flux. Leakage and moderation were varied systematically through the use of different diameter spheres, with and without water. Some of these experiments with bare fission chambers have been evaluated by the International Criticality Safety Benchmark Evaluation Project (ICSBEP)[4].

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 Application of the SCALE TSUNAMI Tools for the Validation of Criticality Safety Calculations Involving 233U written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Radiochemical Development Facility at Oak Ridge National Laboratory has been storing solid materials containing 233U for decades. Preparations are under way to process these materials into a form that is inherently safe from a nuclear criticality safety perspective. This will be accomplished by down-blending the 233U materials with depleted or natural uranium. At the request of the U.S. Department of Energy, a study has been performed using the SCALE sensitivity and uncertainty analysis tools to demonstrate how these tools could be used to validate nuclear criticality safety calculations of selected process and storage configurations. ISOTEK nuclear criticality safety staff provided four models that are representative of the criticality safety calculations for which validation will be needed. The SCALE TSUNAMI-1D and TSUNAMI-3D sequences were used to generate energy-dependent k{sub eff} sensitivity profiles for each nuclide and reaction present in the four safety analysis models, also referred to as the applications, and in a large set of critical experiments. The SCALE TSUNAMI-IP module was used together with the sensitivity profiles and the cross-section uncertainty data contained in the SCALE covariance data files to propagate the cross-section uncertainties (??/?) to k{sub eff} uncertainties (?k/k) for each application model. The SCALE TSUNAMI-IP module was also used to evaluate the similarity of each of the 672 critical experiments with each application. Results of the uncertainty analysis and similarity assessment are presented in this report. A total of 142 experiments were judged to be similar to application 1, and 68 experiments were judged to be similar to application 2. None of the 672 experiments were judged to be adequately similar to applications 3 and 4. Discussion of the uncertainty analysis and similarity assessment is provided for each of the four applications. Example upper subcritical limits (USLs) were generated for application 1 based on trending of the energy of average lethargy of neutrons causing fission, trending of the TSUNAMI similarity parameters, and use of data adjustment techniques.

Download or read book MCNP written by and published by . This book was released on 1993 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past, criticality safety analyses related to the handling and storage of fissile materials were obtained from critical experiments, nuclear safety guides, and handbooks. As a result of rising costs and time delays associated with critical experiments, most experimental facilities have been closed, triggering an increased reliance on computational methods. With this reliance comes the need and requirement for redundant validation by independent criticality codes. Currently, the KENO Monte Carlo transport code is the most widely used tool for criticality safety calculations. For other transport codes, such as MCNP, to be accepted by the criticality safety community as a redundant validation tool they must be able to reproduce experimental results at least as well as KENO. The Monte Carlo neutron, photon, and electron transport code MCNP, has an extensive list of attractive features, including continuous energy cross sections, generalized 3-D geometry, time dependent transport, criticality k{sub eff} calculations, and comprehensive source and tally capabilities. It is widely used for nuclear criticality analysis, nuclear reactor shielding, oil well logging, and medical dosimetry calculations. This report specifically addresses criticality and benchmarks the KENO 25 problem test set. These sample problems constitute the KENO standard benchmark set and represent a relatively wide variety of criticality problems. The KENO Monte Carlo code was chosen because of its extensive benchmarking against analytical and experimental criticality results. Whereas the uncertainty in experimental parameters generally prohibits code validation to better than about 1% in k{sub eff}, the value of k{sub eff} for criticality is considered unacceptable if it deviates more than a few percent from measurements.

Download or read book Bias and Uncertainty of Critical Experiment Models with CSAS25 from SCALE4 4a for Criticality Safety Analyses On the HP J 5600 CMODB Workstation written by and published by . This book was released on 2001 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report documents establishment of bias, bias trends and uncertainty for validation of the CSAS25 control module from the SCALE 4.4a computer code system for use in evaluating criticality safety of uranium systems. The 27-group ENDF/B-IV, 44-group ENDF/B-V, and 238-group ENDF/B-V cross-section libraries were used. The criticality validation calculations were performed using over 500 benchmark cases from Volumes II and IV of the ''International Handbook of Evaluated Criticality Safety Benchmark Experiments, '' published by the Nuclear Energy Agency Organization for Economic Cooperation and Development (NEA/OECD). Based on statistical analysis of the calculation results, the bias, bias trends and uncertainty of the benchmark calculations have been established for these benchmark experiments. Numerical methods for applying margins are briefly described, but the determination of appropriate correlating parameter and values for additional margin, applicable to a particular analysis, must be determined as part of process analysis. As such, this document does not specify upper subcritical limits as has been done in the past. A follow-on report will be written to assess the methods for determination of an upper safety limit in more detail, provide comparisons, and recommend a preferred method. Analysts using these results are responsible for exercising sound engineering judgment using strong technical arguments to develop a margin in k{sub eff} or other correlating parameter that is sufficiently large to ensure that conditions (calculated by this method to be subcritical by this margin) will actually be subcritical. Documentation of determination and justification of the appropriate margin in the analyst's evaluation, in conjunction with this report, will constitute the complete Validation Report in accordance with ANSI/ANS-8.1-1998, Section 4.3.6(4).

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:

Download or read book Investigations and Recommendations on the Use of Existing Experiments in Criticality Safety Analysis of Nuclear Fuel Cycle Facilities for Weapons Grade Plutonium written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sensitivity and Uncertainty (S/U) methods, recently developed at Oak Ridge National Laboratory (ORNL) have been demonstrated to determine the applicability of critical benchmark experiments to the criticality code validation of design systems. These methods, although still under development, have been recently published in several sources. Development of the techniques used in this report was conducted through joint support from the United States Department of Energy (U.S. DOE) and the Nuclear Regulatory Commission (NRC) to provide a physics-based approach for the establishment of the area of applicability of critical experiments per the requirements of ANSI/ANS-8.1. Use of these methods may allow users to interpolate and extrapolate the traditional area of applicability (AOA) of a given set of critical experiments to include new application areas that may not have been anticipated during the experiment design. The new S/U analytical tools include the SEN1 and SEN3 sensitivity analysis sequences, which will be available with the next release of the Standardized Computer Analyses for Licensing Evaluation (SCALE) code system. These analysis sequences compute the relative change in the system neutron multiplication factor, k{sub eff}, which would be observed for perturbations in the group-wise neutron cross-section data for each reaction of each nuclide in the system. The CANDE code uses sensitivity data determined separately for the design system applications and the individual experiments, along with the cross-section-covariance data, to calculate integral parameters which give a measure of the similarity between a particular design system and an experimental benchmark. A high-valued integral parameter for an experiment application pair indicates that the experiment demonstrates similar properties to the application. Thus, the experiment is applicable for the criticality code validation of the design system. A theoretical basis for the S/U techniques applied in this report is given in Sect. 2. This report pertains to two of the five AOAs identified by the licensee [Duke, Cogema, Stone and Webster (DCS)] for the validation of criticality codes in the design of the Mixed-Oxide Fuel Fabrication Facility (MFFF). The five AOAs are as follows: (1) Pu-nitrate aqueous solutions (homogeneous systems), (2) Mixed-oxide (MOX) pellets, fuel rods and fuel assemblies (heterogeneous systems), (3) PuO2 powders, (4) MOX powders, and (5) Aqueous solutions of Pu compounds (Pu-oxalate solutions). This report addresses a S/U analysis pertaining to AOA 3, PuO2 powders, and AOA 4, MOX powders. AOA 3 and AOA 4 are the subject of this report since the other AOAs (solutions and heterogeneous systems) appear to be well represented in the documented benchmark experiments used in the criticality safety community. Prior to this work, DCS used traditional criticality validation techniques to identify numerous experimental benchmarks that are applicable to AOAs 3 and 4. Traditional techniques for selection of applicable benchmark experiments essentially consist of evaluating the area of applicability for important design parameters (e.g., Pu content or average neutron energy) and ensuring experiments have similar characteristics that bound or nearly bound the range of conditions requiring design analysis. DCS provided ORNL with compositions and dimensions for critical systems used to establish preliminary mass limits for facility powder and fuel pellet handling areas corresponding to AOAs 3 and 4. ORNL has reviewed existing critical experiments to identify those, which, in addition to those provided by DCS, may be applicable to the criticality code validation for AOAs 3 and 4. A S/U analysis was then performed to calculate the integral parameters used to determine the similarity of each critical experiment to each design system provided by DCS. This report contains a review of the S/U theory, a description of the design systems, a brief description of the critical experiments evaluated for applicability, and the results of the S/U analysis determining the applicability of each experiment to each application.

Download or read book Nuclear Criticality Safety written by Berry F. Estes and published by . This book was released on 1980 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Needs for Criticality Safety Purposes written by Nuclear Energy Agency and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Guide to Verification and Validation of the SCALE 4 Criticality Safety Software written by and published by . This book was released on 1996 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: Whenever a decision is made to newly install the SCALE nuclear criticality safety software on a computer system, the user should run a set of verification and validation (V & V) test cases to demonstrate that the software is properly installed and functioning correctly. This report is intended to serve as a guide for this V & V in that it specifies test cases to run and gives expected results. The report describes the V & V that has been performed for the nuclear criticality safety software in a version of SCALE-4. The verification problems specified by the code developers have been run, and the results compare favorably with those in the SCALE 4.2 baseline. The results reported in this document are from the SCALE 4.2P version which was run on an IBM RS/6000 workstation. These results verify that the SCALE-4 nuclear criticality safety software has been correctly installed and is functioning properly. A validation has been performed for KENO V.a utilizing the CSAS25 criticality sequence and the SCALE 27-group cross-section library for 233U, 235U, and 239Pu fissile, systems in a broad range of geometries and fissile fuel forms. The experimental models used for the validation were taken from three previous validations of KENO V.a. A statistical analysis of the calculated results was used to determine the average calculational bias and a subcritical k{sub eff} criteria for each class of systems validated. Included the statistical analysis is a means of estimating the margin of subcriticality in k{sub eff}. This validation demonstrates that KENO V.a and the 27-group library may be used for nuclear criticality safety computations provided the system being analyzed falls within the range of the experiments used in the validation.