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Li, C.-Y.; Uchibori, Akihiro; Takata, Takashi; Pellegrini, M.*; Erkan, N.*; Okamoto, Koji*
Dai-25-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 4 Pages, 2021/07
The capability of stable cooling and avoiding re-criticality on the debris bed are the main issues for achieving IVR (In-Vessel Retention). In the actual situation, the debris bed is composed of mixed-density debris particles. Hence, when these mixed-density debris particles were launched to re-distribute, the debris bed would possibly form a density-stratified distribution. For the proper evaluation of this scenario, the multi-physics model of CFD-DEM-Monte-Carlo based neutronics is established to investigate the coolability and re-criticality on the heterogeneous density-stratified debris bed with considering the particle relocation. The CFD-DEM model has been verified by utilizing water injection experiments on the mixed-density particle bed in the first portion of this research. In the second portion, the coupled system of the CFD-DEM-Monte-Carlo based neutronics model is applied to reactor cases. Afterward, the debris particles' movement, debris particles' and coolant's temperature, and the k-eff eigenvalue are successfully tracked. Ultimately, the relocation and stratification effects on debris bed's coolability and re-criticality had been quantitatively confirmed.
Di Lemma, F. G.; Nakajima, Kunihisa; Yamashita, Shinichiro; Osaka, Masahiko
Journal of Nuclear Materials, 484, p.174 - 182, 2017/02
Times Cited Count:22 Percentile:90.23(Materials Science, Multidisciplinary)Chemisorption phenomena can affect fission products retention in the nuclear reactor vessel during a Severe Accident (SA). This paper will describe the influence of molybdenum contained in type 316 stainless steel (SS) on Cs chemisorption. Our experiments showed the formation of Cs-Mo compounds in addition to CsFeSiO, observed previously on SS304. The results of high temperature stability tests on the deposits are also presented. These tests aimed at simulating the revaporization of FP from structural materials during a SA. From our results, it can be inferred that Cs-Mo deposits may revaporize, contributing as a delayed source to the radioactive release.
Nakashima, Mikio; Nakashio, Nobuyuki; Kameo, Yutaka; Fukui, Toshiki*; Isobe, Motoyasu*; Otake, Atsushi*; Wakui, Takuji*; Hirabayashi, Takakuni*
Radiochimica Acta, 91(1), p.45 - 51, 2003/01
Times Cited Count:2 Percentile:18.9(Chemistry, Inorganic & Nuclear)no abstracts in English
Uetsuka, Hiroshi; Nagase, Fumihisa; *
JAERI-Research 95-084, 36 Pages, 1995/11
no abstracts in English
; ; ;
Journal of Radiation Research, 9(3-4), p.129 - 134, 1968/00
no abstracts in English