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Journal Articles

Validation of MOSRA-SRAC for burnup of a BWR fuel assembly

Kojima, Kensuke

Proceedings of International Conference on the Physics of Reactors; Unifying Theory and Experiments in the 21st Century (PHYSOR 2016) (USB Flash Drive), p.3283 - 3292, 2016/05

The MOSRA system has been developing to improve the applicability of the neutronic characteristic analyses. The cell calculation module MOSRA-SRAC is a core module of MOSRA, and applicability tests for realistic problems are required. As a test, MOSRA-SRAC is validated by comparison with measured values. As the measurement, the post irradiation examination SFCOMPO 99-5 is chosen. In the examination, the compositions of major heavy metal and fission product nuclides in a UO $_{2}$ -Gd $_{2}$ O $_{3}$ fuel rod pulled from the 88 BWR fuel assembly used in TEPCO's Fukushima-Daini-2 were measured. The result shows good agreement between calculated and measured value. For uranium and plutonium nuclides, calculated values agree within 5% except for $^{238}$ Pu. $^{238}$ Pu composition is overestimated by 30%, and the overestimation is caused by the unclearness of the void faction history of the fuel rod. For fission products, calculated values agree within approximately 10%.

Journal Articles

Classification of criticality calculations with correlation coefficient method and its application to OECD/NEA burnup credit benchmarks phase III-A and II-A

Okuno, Hiroshi

Journal of Nuclear Science and Technology, 40(7), p.544 - 551, 2003/07

https://doi.org/10.3327/jnst.40.544

Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)

A method for classifying benchmark results of criticality calculations according to similarity was proposed in this paper. After formulation of the method utilizing correlation coefficients, it was applied to burnup credit criticality benchmarks Phase III-A and II-A, which were conducted by the Expert Group on Burnup Credit Criticality Safety under auspices of the OECD/NEA. Phase III-A benchmark was a series of criticality calculations for irradiated BWR fuel assemblies, whereas Phase II-A benchmark was a suite of criticality calculations for irradiated PWR fuel pins. These benchmark problems and their results were summarized. The correlation coefficients were calculated and sets of benchmark results were classified according to the criterion that the correlation coefficients were no less than 0.15 for Phase III-A and 0.10 for Phase II-A benchmarks. When a couple of results were in a same group, one result was found predictable from the other. An example was shown for each of the Benchmarks. The evaluated nuclear data seemed the main factor of errors.

Journal Articles

Fast vector computation of the characteristics method

Kugo, Teruhiko

Journal of Nuclear Science and Technology, 39(3), p.256 - 263, 2002/03

https://doi.org/10.3327/jnst.39.256

Times Cited Count：3 Percentile：23.41(Nuclear Science & Technology)

Two vector computation algorithms; an odd-even sweep (OES) method and an independent sequential sweep (ISS) method, have been developed for the characteristics method to solve the neutron transport equation in a heterogeneous geometry. They realize long vector lengths without recursive operations for effective use of vector computers. Their efficiency has been investigated to a realistic fuel assembly calculation. For both methods, a vector computation is 15 times faster than a scalar computation. From a viewpoint of a comparison between the OES and ISS methods, the ISS method is superior to the OES method because the ISS method shows a faster convergence and saves a computer memory without reducing a computation speed.

JAEA Reports

Fast computation of the characteristics method on vector computers

Kugo, Teruhiko

JAERI-Research 2001-051, 39 Pages, 2001/11

JAERI-Research-2001-051.pdf:2.04MB

Fast computation of the characteristics method to solve the neutron transport equation in a heterogeneous geometry has been studied. Two vector computation algorithms; an odd-even sweep (OES) method and an independent sequential sweep (ISS) method have been developed and their efficiency to a typical fuel assembly calculation has been investigated. For both methods, a vector computation is 15 times faster than a scalar computation. From a viewpoint of comparison between the OES and ISS methods, the ISS method is superior to the OES method because the ISS method shows a faster convergence and saves a computer memory without reducing a computation speed. In the vector computation, a table-look-up method to reduce computation time of an exponential function saves only 20% of a whole computation time. Both the coarse mesh rebalance method and the Aitken acceleration method are effective as acceleration methods for the characteristics method, a combination of them saves 70-80% of outer iterations compared with a free iteration.

Journal Articles