Download or read book New Possibilities of Calculating Independent Fission Product Yields written by V. Valenta and published by . This book was released on 1977 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Treatment of Fission Yield Effects and Method Development for Improved Reactor Depletion Calculations written by Kern, Kilian and published by KIT Scientific Publishing. This book was released on 2019-03-01 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of Inconsistent ENDF B VII 1 Independent and Cumulative Fission Product Yields with Proposed Revisions written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A recent implementation of ENDF/B-VII. independent fission product yields and nuclear decay data identified inconsistencies in the data caused by the use of updated nuclear scheme in the decay sub-library that is not reflected in legacy fission product yield data. Recent changes in the decay data sub-library, particularly the delayed neutron branching fractions, result in calculated fission product concentrations that are incompatible with the cumulative fission yields in the library, and also with experimental measurements. A comprehensive set of independent fission product yields was generated for thermal and fission spectrum neutron induced fission for 235,238U and 239,241Pu in order to provide a preliminary assessment of the updated fission product yield data consistency. These updated independent fission product yields were utilized in the ORIGEN code to evaluate the calculated fission product inventories with experimentally measured inventories, with particular attention given to the noble gases. An important outcome of this work is the development of fission product yield covariance data necessary for fission product uncertainty quantification. The evaluation methodology combines a sequential Bayesian method to guarantee consistency between independent and cumulative yields along with the physical constraints on the independent yields. This work was motivated to improve the performance of the ENDF/B-VII. 1 library in the case of stable and long-lived cumulative yields due to the inconsistency of ENDF/B-VII. 1 fission p;roduct yield and decay data sub-libraries. The revised fission product yields and the new covariance data are proposed as a revision to the fission yield data currently in ENDF/B-VII. 1.
Download or read book Distribution of Independent Fission product Yields to Isomeric States written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A simple one-parameter model is presented for calculating the distribution of independent yield strength between ground and isomeric states of primary fission products formed by neutron-induced fission of actinide nuclei. Yield branching ratios are calculated as a function of neutron energy (thermal, fast, and 14-MeV) for 144 nuclides having isomeric states with T12 greater than or equal to 0.1 s. The results are proposed for use in the ENDF/B-V yield files.
Download or read book A New Evaluation of Fission Product Yields and the Production of Independent and Cumulative Yields written by M. R. James and published by . This book was released on 1991 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Evaluation of Fission Product Yields and the Production of a New Library Ukfy2 of Independent and Cumulative Yields written by M. F. James and published by . This book was released on 1991-12-01 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Method for Estimating the Fractional Yields from Low and Medium energy Neutron Induced Fission written by Kurt Wolfsberg and published by . This book was released on 1965 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Evaluation of Fission Product Yields and the Production of a New Library Ukfy2 of Independent and Cumulative Yields written by M. F. James and published by . This book was released on 1991-12-01 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fission Product Yields written by Katharine Way and published by . This book was released on 1950 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A NEW EVALUATION OF FISSION PRODUCT YIELDS AND THE PRODUCTION OF A NEW LIBRARY UKFY2 OF INDEPENDENT AND CUMULATIVE YIELDS PART 1 METHODS AND OUTLINEOF THE EVALUATION written by M. F. James and published by . This book was released on 1991 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Calculations Related to Nuclear Fission product Yields written by A. D. Efimenko and published by . This book was released on 1997 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determination of Fission Product Yields of 235U Using Gamma Ray Spectroscopy written by Christopher Hing Lu and published by . This book was released on 2012 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is important to have a method of experimentally calculating fission product yields. Statistical calculations and simulations produce very large uncertainties. Experimental calculations, depending on the methods used, tend to produce lower uncertainties. This work set up a method to calculate fission product yields using gamma ray spectroscopy. In order to produce a method that was theoretically sound, a simulation was set up using OrigenArp to calculate theoretical concentrations of fission products from the irradiation of natural uranium. From these concentrations, the fission product yields were calculated to verify that they would agree with expected values. Moving forward in the work, the total flux at the point of irradiation, in the pneumatic transfer system, was calculated and determined to be 3.9070E+11 ± 6.9570E+10 n/cm2/s at 100 kW. Once the flux was calculated, the method for calculating fission product yields was implemented and yields were calculated for 10 fission products. The yields calculated were in very good agreement (within 10.04%) with expected values taken from the ENDF-349 library. This method has strong potential in nuclear forensics as it can provide a means for developing a library of experimentally-determined fission product yields, as well as rapid post-nuclear detonation analysis.
Download or read book New Evaluation of Fission Product Yields and the Production of a New Library Ukfy2 of Independant and Cumulative Yields written by M.F. James and published by . This book was released on 1991-12-01 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Computer Code for the Calculation of Fission Product Activity Ratios written by Oden, D. R. and published by . This book was released on 1971 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Fission Product After heat written by Bernard I. Spinrad and published by . This book was released on 1978 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determination of Independent and Cumulative Fission Product Yields with Gamma Spectrometry written by Kenneth Joseph Dayman and published by . This book was released on 2015 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fission product yields are vital to nuclear forensics and safeguards missions, especially active interrogation technologies and post-event forensic response. However, there have been limited experimental measurements performed to date, and the majority of the existing data is based on nuclear models. Updates to the nuclear data such as branching ratios have been made over time, the need for new measurements has come to light as datasets are no longer self-consistent and there are significant discrepancies between datasets. A method has been developed to determine independent and cumulative fission product yields using Bayesian inference. The methodology combines gamma-ray spectrometry, nuclide transmutation and burnup modeling, numerical optimization, and Monte Carlo sampling. The developed convex optimization was solved using three solvers: the Nelder-Mead Simplex direct search, the Levenberg-Marquardt algorithm, and Newton's Method. Sources of uncertainty were treated using sensitivity coefficient estimation with perturbation analysis as well as Monte Carlo sampling to determine uncertainty in the estimated values for fission product yields and produce uncertainty budgets. Each part of the analysis method was verified using controlled data analysis experiments with known results and then validated with two experiments. The Levenberg-Marquardt algorithm is the fastest and most reliable approach to optimization of three algorithms tested, and Monte Carlo sampling better treated uncertainty by explicitly treating correlations between input parameters, accounting for higher-order effects neglected by first-order sensitivity coefficients, and providing entire probability distributions for results. Thermal irradiations were performed at The University of Texas to produce fission products by bombarding naturally enriched U3O8 in a thermal neutron field provided by the 1.1 MW TRIGA reactor's thermal pneumatic transfer irradiation facility. Eleven long-lived fission products were identified and quantified using a series of gamma-ray spectra collected of the sample after the end of irradiation. Molybdenum-99 was used as an internal standard to estimate the time-averaged neutron flux incident on the sample, resulting in a value of (2.26 ± 0.24) × 1010 cm−2s−1, which agrees with prior operator experience. Fission product yields for the other ten identified radionuclides were estimated. The results agreed reasonably with literature values. Biases relative to literature values are positive and negative with an average bias of 6.3%, and the absolute relative error is 9.7%, suggesting that no systematic biases or major sources of untreated error were present in the analysis. Scientists at Pacific Northwest National Laboratory irradiated a 220 mg 235U foil with greater than 99% enrichment in a 14.1 MeV neutron field using a neutron generator and collected list-mode gamma-ray counting data. These data were parsed at The University of Texas to create sets of twenty-minute and twelve-hour gamma-ray spectra that were used to identify and quantify short- and long-lived fission products, respectively. In total, nineteen fission products with half-lives ranging from 3.2 minutes to 64.0 days were studied. The neutron flux of (2.36 ± 0.11) × 108 cm−2s−1 was estimated using 99Mo as an internal standard, and the determined value was used to calculate fission product yields of the remaining fission products. Determined values differ greatly from literature values; however, literature values for 14.1 MeV neutrons are less studied, especially for short-lived nuclides, and gamma-ray measurements of long-lived fission products are unreliable due to the small number of fissions that occurred during irradiation. Despite the limitations of the data, the results of the analyses are positive and confirm the viability of the developed methodology for further fission product yield analysis, as well as other nuclear data measurements, and application to nuclear forensics and safeguards inverse problems.
Download or read book Cumulative and Independent Fission Product Yield Measurements written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A technique for measuring short lived fission product cumulative and independent yields is demonstrated. This method could greatly expand the database for testing and benchmarking calculational codes for spallation product yields. A proposed experimental arrangement for the spallation target which incorporates the fission chamber is also presented.
