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Kaji, Yoshiyuki; Nemoto, Yoshiyuki; Nagatake, Taku; Yoshida, Hiroyuki; Tojo, Masayuki*; Goto, Daisuke*; Nishimura, Satoshi*; Suzuki, Hiroaki*; Yamato, Masaaki*; Watanabe, Satoshi*
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 8 Pages, 2019/05
In this research program, cladding oxidation model in SFP accident condition, and numerical simulation method to evaluate capability of spray cooling system which was deployed for spent fuel cooling during SFP accident, have been developed. These were introduced into the severe accident codes such as MAAP and SAMPSON, and SFP accident analyses were conducted. Analyses using Computational Fluid Dynamics (CFD) code were conducted as well for the comparison with SA code analyses and investigation of detail in the SFP accident. In addition, three-dimensional criticality analysis method was developed as well, and safer loading pattern of spent fuels in pool was investigated.
Iijima, Shizuka; Uchida, Naoki; Taguchi, Katsuya; Washiya, Tadahiro
JAEA-Review 2015-018, 39 Pages, 2015/11
JAEA-Review-2015-018.pdf:3.95MB
There is a possibility that the fuel assemblies stored in the spent fuel pool (SFP) at Fukushima Daiichi NPS (or Nuclear Power Station) are not only exposed to seawater and concrete fragments, but also damaged by fallen rubbles. We checked the reprocessing experiences of leak fuels at Tokai Reprocessing Plant and overseas reprocessing facilities, and the storage conditions and the checked and inspected results of the fuel stored in the SFP at Fukushima Daiichi NPS, after that, we listed up the technological problems with reprocessing damaged nuclear fuels and selected elements of the research for the purpose of drawing indicators to make a judgmental decision of the possibility of damaged nuclear fuels reprocessing. And we drew the indicators to make a judgmental decision on the possibility of reprocessing based on the results of the examination and the study about elements of the research.
Ioka, Ikuo; Kato, Hitoshi; Ogawa, Hiroaki
no journal, ,
When the function of cooling system for a spent fuel pool is lost, the spent fuel pin is exposed to steam and air environment. In addition, oxidation behavior of the cladding may be changed due to axial temperature gradient and induced stress gradient during the process of dry out of the spent fuel pool. The oxidation behavior of the Zircaloy-2 cladding under axial temperature gradient was investigated in this study. The axial temperature gradients was about 100 
C/cm. The oxidation test was carried out at 600 C in the saturated steam flow with Ar of 0.5 l/min as a career gas. Little difference was seen in the configuration of the surface cracks and the oxide thickness of specimens oxidized with different temperature gradients. Consequently, the high-temperature oxidation of Zircaloy-2 cladding was hardly changed by the steep axial temperature gradient of about 100 C/cm in this study.
