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Tamaki, Hitoshi; Hamaguchi, Yoshikane; Yoshida, Kazuo; Muramatsu, Ken
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10
A PSA procedure for MOX fuel fabrication facilities is being developed at the JAERI. This procedure consists of four steps, which are hazard analysis, accident scenario analysis, frequency evaluation and consequence evaluation. The proposed procedure is characterized by the hazard analysis step. The Hazard analysis step consists of two sub-steps. In the first sub-step, a variety of functions of equipment composing the facility are analyzed to identify potential abnormal events exhaustively. In the second sub-step, these potential events are screened to select abnormal events by using a risk matrix based on the rough estimation of likelihood and maximum unmitigated release of radioactive material. One of the unique technical issues in this research is the estimation of likelihood of criticality event. A method is also proposed as a part of PSA procedure taking into consideration of failure of a computerized control system for MOX powder handling process. The applicability of the PSA procedure was demonstrated through the trial application of it to a model plant of MOX fuel fabrication facility.
Tashiro, Shinsuke; Abe, Hitoshi; Morita, Yasuji
JAERI-Conf 2005-007, p.348 - 350, 2005/08
Hot test at Rokkasho Reprocessing plant has been started since last year. In addition, construction of the MOX fuel fabrication facility at Rokkasho site is planning. So, the importance of safety evaluation of the nuclear fuel cycle facility is increasing. Under the fire accident, one of the serious postulated accidents in the nuclear fuel cycle facility, the equipments (glove-box, ventilation system, ventilation filters etc.) for the confinement of the radioactive materials within the facility could be damaged by a large amount of heat and smoke released from the combustion source. Therefore, the fundamental data and models calculating for the amount of heat and smoke released from the combustion source under such accident are important for the safety evaluation of the facility. In JAERI, the study focused on the evaluation of amount of heat and smoke released from the combustion source is planning. In this paper, the outline of experimental apparatus, measurement items and evaluation terms are described.
Tamaki, Hitoshi; Yoshida, Kazuo; Watanabe, Norio; Muramatsu, Ken
Proceedings of International Topical Meeting on Probabilistic Safety Analysis (PSA '05) (CD-ROM), 11 Pages, 2005/00
A probabilistic safety assessment (PSA) procedure for Mixed Oxide (MOX) fuel fabrication facilities is being developed applicable to nuclear facilities at Japan Atomic Energy Research Institute (JAERI). As part of the PSA procedure, the approach to hazard analysis was established, which consists of two analysis steps: Functional Failure Modes and Effects Analysis (Functional FMEA) and Risk Matrix Analysis. In the Functional FMEA, a variety of functions of equipment composing the facility are analyzed to identify potential abnormal events exhaustively. In the second step, these potential events are screened to select abnormal events as candidate events to be analyzed for frequency and consequence by using two-dimensional matrix based on the rough estimation of likelihood and maximum unmitigated release of radioactive material. The applicability of the hazard analysis approach established was demonstrated through the trial application of the PSA procedure being developed to model plant of MOX fuel fabrication facility.
JAERI-Tech 96-001, 135 Pages, 1996/01
no abstracts in English
Fujine, Sachio; Takano, Hideki; Sato, Osamu; Tone, Tatsuzo; Yamada, Takashi*; Kurosawa, Katsutoshi*
JAERI-M 93-157, 157 Pages, 1993/08
no abstracts in English
Yamada, Yoshikazu; Kawaguchi, Koichi; Segawa, Tomoomi; Matsumura, Tatsuro; Kato, Masato
no journal, ,
Researchers at Japan Atomic Energy Agency (JAEA) have proposed the transmutation of minor actinides (MAs) by both fast reactors (FRs) and accelerator driven systems (ADSs) as a way to contribute significantly to the reduction of the volume and the potential radiotoxicity of radioactive wastes. Pu-U mixed oxide with small amount of MA is adopted as fuel of FRs, while U-free nitride and mixed oxide of MA, Pu and inert element are candidates for fuel of ADSs. JAEA researchers have also studied the simplified MOX fuel fabrication process to decrease the fabrication cost. This report describes a technological investigation of the simplified MA-bearing fuel fabrication process that prepares fuel suitable for both FRs and ADSs. Furthermore, this report includes an analysis of the feasibility of fabricating MA macro-dispersion pellets and MA micro-dispersion pellets for ADSs by using the simplified MOX fabrication process. The flowabilities of both de-nitrated raw powders were improved with the tumbling granulator, and the Carr flowability index was more than 70 for both. The green pellets had no defects in their appearance such as cracks. The CeO
particles were dispersed homogeneously in both macro-dispersion and micro-dispersion pellets. As a result, it was judged that the simplified MOX fuel fabrication process is applicable to fabrication of MOX pellets for ADSs as well as FRs.
