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Miura, Takatomo; Kudo, Atsunari; Koyama, Daisuke; Obu, Tomoyuki; Samoto, Hirotaka
Proceedings of 12th International Conference on Nuclear Criticality Safety (ICNC2023) (Internet), 10 Pages, 2023/10
Tokai Reprocessing Plant (TRP) had reprocessed 1,140 tons of spent fuel discharged from commercial reactors (BWR, PWR) and Advanced Thermal Reactor "Fugen" from 1977 to 2007. TRP had entered decommissioning stage in 2018. In order to reduce the risk of High Active Liquid Waste (HALW) held at the facility, the vitrification of HALW is given top priority. HALW generated from reprocessing of spent fuel contains not only fission products (FPs) but also trace amounts of uranium (U) and plutonium (Pu) within the liquid and insoluble residues (sludge). Under normal conditions, concentrations of U and Pu in HALW are very low so that it can not reach criticality. Since FPs with high neutron absorption effect coexists in HALW, even if the cooling function is lost due to serious accident and HALW evaporates to dryness, it is considered that criticality would not been reached. In order to confirm this estimation quantitatively, criticality safety evaluations were carried out for the increase of U and Pu concentrations by evaporation of HALW to the point of dryness. In this evaluation, infinite multiplication factors were calculated for each of solution system and sludge system of HALW with respect to the concentration change through evaporation to dryness. It is confirmed it could not reach criticality. The abundance ratios of U, Pu and FPs were set conservatively based on analytical data and ORIGEN calculation results. Multiplation factors for two-layer infinite slab model of solution and sludge systems of HALW were also calculated, and it was confirmed it could not reached criticality. In conclusion, the result was gaind that there could be no criticality even in the process through evaporation to dryness of HALW in TRP.
Abe, Hitoshi; Tashiro, Shinsuke; Morita, Yasuji
JAERI-Conf 2005-007, p.199 - 204, 2005/08
Source term data for estimating release behavior of radioactive nuclides is necessary to evaluate synthetic safety of nuclear fuel cycle facility under accident conditions, such as fire and criticality. In JAERI, the data has been obtained by performing some demonstration tests. In this paper, the data for the criticality accident in fuel solution obtained from the TRACY experiment, will be mainly reviewed. At 4.5 h after the transient criticality, the release ratio of the iodine were about 0.2% for re-insertion of transient rod at just after transient criticality and about 0.9% for not re-insertion. Similarly the release coefficient and release ratio for Xe were estimated. It was proved that the release ratio of Xe-141 from the solution was over 90% in case that the inverse period was over about 100 (1/s). Furthermore, outline of the study on the fire accident as future plan will be also mentioned.
Abe, Hitoshi; Tashiro, Shinsuke; Morita, Yasuji
JAERI-Research 2004-014, 19 Pages, 2004/09
no abstracts in English
Working Group on Nuclear Criticality Satety Data
JAERI-Review 2001-028, 217 Pages, 2001/08
no abstracts in English
Murazaki, Minoru*;
JAERI-Data/Code 99-019, 103 Pages, 1999/03
no abstracts in English
Working Group on Nuclear Criticality Satety Data
JAERI 1340, 189 Pages, 1999/03
no abstracts in English
Komuro, Yuichi
Nihon Genshiryoku Gakkai-Shi, 40(9), p.697 - 701, 1998/00
Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)no abstracts in English
Naito, Yoshitaka; Okuno, Hiroshi
JAERI-Review 95-013, 397 Pages, 1995/09
no abstracts in English
Naito, Yoshitaka; *; Yamamoto, Toshihiro; Komuro, Yuichi
JAERI-Research 95-029, 69 Pages, 1995/03
no abstracts in English
Kurosawa, Masayoshi; Naito, Yoshitaka; *
ICNC 95: 5th Int. Conf. on Nuclear Criticality Safety, Vol. I, 0, p.2.11 - 2.15, 1995/00
no abstracts in English
*; Naito, Yoshitaka
JAERI-M 91-164, 25 Pages, 1991/10
no abstracts in English
Takeshita, Isao; Nomura, Masayuki; ; Izawa, Naoki; Yanagisawa, Hiroshi
Proc. of the 3rd Int. Conf. on Nuclear Fuel Reprocessing and Waste Management,Vol. 1, p.510 - 515, 1991/00
no abstracts in English
; ; *
Transactions of the American Nuclear Society, 41, p.330 - 332, 1982/00
no abstracts in English
; ;
Transactions of the American Nuclear Society, 41, p.329 - 330, 1982/00
no abstracts in English