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Buiron, L.*; Rimpault, G*; Fontaine, B.*; Kim, T. K.*; Stauff, N. E.*; Taiwo, T. A.*; Yamaji, Akifumi*; Gulliford, J.*; Fridmann, E.*; Pataki, I.*; et al.
Proceedings of International Conference on the Physics of Reactors; The Role of Reactor Physics toward a Sustainable Future (PHYSOR 2014) (CD-ROM), 16 Pages, 2014/09
Within the activities of the Working Party on Scientific Issues of Reactor Systems (WPRS) of the OECD, an international collaboration is ongoing on the neutronic analyses of several Generation-IV Sodium-cooled Fast Reactor (SFR) concepts. This paper summarizes the results obtained by participants from institutions of different countries (ANL, CEA, ENEA, HZDR, JAEA, CER, KIT, UIUC) for the large core numerical benchmarks. These results have been obtained using different calculation methods and analysis tools to estimate the core reactivity and isotopic composition evolution, neutronic feedbacks and power distribution. For the different core concepts analyzed, a satisfactory agreement was obtained between participants despite the different calculation schemes used. A good agreement was generally obtained when comparing compositions after burnup, the delayed neutron fraction, the Doppler coefficient, and the sodium void worth. However, some noticeable discrepancies between the k-effective values were observed and are explained in this paper. These are mostly due to the different neutronic libraries employed (JEFF3.1, ENDFB7.0 or JENDL-4.0) and to a lesser extent the calculations methods.
Okuno, Hiroshi
Journal of Nuclear Science and Technology, 40(7), p.544 - 551, 2003/07
Times Cited Count：0 Percentile：0.00(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.
Okuno, Hiroshi; Sakai, Tomohiro*
Nuclear Technology, 140(3), p.255 - 265, 2002/12
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)In order to facilitate discussions based on quantitative analysis about the end effect, which is often talked about in connection to burnup credit in criticality safety evaluation of spent fuel, we introduced in this paper a burnup importance function. This function shows the burnup effect on the reactivity as a function of the fuel position; an explicit expression of this function was derived according to the perturbation theory. The burnup importance function was applied to the Phase IIA benchmark model that was adopted by the OECD/NEA Expert Group on Burnup Credit Criticality Safety. The function clearly displayed that burnup importance of the end regions increases (1) as burnup, (2) as cooling time, (3) in consideration of burnup profile, and (4) in consideration of fission products.
Okuno, Hiroshi; Tonoike, Kotaro; Sakai, Tomohiro*
Proceedings of International Conference on the New Frontiers of Nuclear Technology; Reactor Physics, Safety and High-Performance Computing (PHYSOR 2002) (CD-ROM), 8 Pages, 2002/10
As the burnup proceeds, reactivity of fuel assemblies for light water reactors decreases by depletion of fissile nuclides, especially in the axially central region. In order to describe the importance of the end regions to the reactivity change, a burnup importance function was introduced as a weighting function to a local burnup variation contributed to a reactivity decrease. The function was applied to the OECD/NEA/BUC Phase II-A model and a simplified Phase II-C model. The application to Phase II-A model clearly showed that burnup importance of the end regions increases as burnup and/or cooling time increases. Comparison of the burnup importance function for different initial enrichments was examined. The application result to the simplified Phase II-C model showed that the burnup importance function was helpful to find the most reactive fuel burnup distribution under the conditions that the average fuel burnup was kept constant and the variations in the fuel burnup were within the maximum and minimum measured values.
Okuno, Hiroshi; Naito, Yoshitaka*; Suyama, Kenya
JAERI-Research 2002-001, 181 Pages, 2002/02
JAERI-Research-2002-001.pdf:10.89MB
The report describes the final results of the Phase IIIB Benchmark conducted by the Expert Group on Burnup Credit Criticality Safety under the auspices of the OECD/NEA. The Benchmark was intended to compare the predictability of current computer code and data library combinations for the atomic number densities of an irradiated BWR fuel assembly model, which was irradiated under specific power of 25.6 MW/tHM up to 40 GWd/tHM and cooled for five years. The void fraction was assumed to be uniform and constant, at 0, 40 and 70%, during burnup. In total, 16 results were submitted from 13 institutes of 7 countries. The calculated densities of 12 actinides and 20 fission product nuclides were found mostly within a range of +- 10% relative to the average, although some results, esp. 155Eu and gadolinium isotopes, exceeded the band. Pin-wise burnup results agreed well among the participants. The results in the multiplication factor also accorded well with each other for void fractions of 0 and 40%; however some results deviated from the average noticeably for the void fraction of 70%.
Okuno, Hiroshi; Naito, Yoshitaka*; Ando, Yoshihira*
JAERI-Research 2000-041, 179 Pages, 2000/09
JAERI-Research-2000-041.pdf:6.11MB
no abstracts in English
Komuro, Yuichi
Journal of Nuclear Science and Technology, 37(6), p.548 - 554, 2000/06
no abstracts in English
Kobayashi, Keisuke*; Sugimura, Naoki*; Nagaya, Yasunobu
Mathematics and Computation, Reactor Physics and Environmental Analysis in Nuclear Applications, p.657 - 666, 1999/00
no abstracts in English
; ; Suyama, Kenya; Ando, Yoshihira*
Proceedings of 6th International Conference on Nuclear Criticality Safety (ICNC '99), 2, p.566 - 575, 1999/00
no abstracts in English
Okajima, Shigeaki
Kaku Deta Nyusu (Internet), (59), p.16 - 23, 1998/02
no abstracts in English
Komuro, Yuichi
Nihon Genshiryoku Gakkai-Shi, 40(9), p.697 - 701, 1998/00
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)no abstracts in English
R.P.Rulko*; Takano, Hideki; C.Broeders*; Wakabayashi, Toshio*; Sasa, Toshinobu; ; D.Lutz*; Mukaiyama, Takehiko; C.Nordborg*
Proc. of Int. Conf. on the Phys. of Nucl. Sci. and Technol., 2, p.1462 - 1469, 1998/00
no abstracts in English
; Okuno, Hiroshi
JAERI-Research 96-003, 170 Pages, 1996/02
JAERI-Research-96-003.pdf:5.24MB
no abstracts in English
JAERI-M 94-003, 145 Pages, 1994/01
no abstracts in English
