Development of Level 2 PSA Methodology for Sodium-Cooled Fast Reactors (4)Development of Technical Basis in the Material-Relocation and Decay-Heat Removal Phases of Unprotected Events
This paper covers, as a part of level 2 PSA methodology development for sodium-cooled fast reactors (SFRs), the event sequences related to the degraded core in the reactor vessel after temporary reactor shutdown following a core disruption due to power-to-flow ratio excursion in an anticipated transient without scram type event. The core-material relocation phase deals with the relocation of the materials especially the fuel remained after the termination of the power-to-flow ratio excursion, followed by the decay-heat removal phase which deals with the cooling of the materials at the location where they are retained steadily. For the evaluation of the event sequences of the core-material relocation phase, computer codes MUTRAN and SIMMER-LT are developed. For the probability evaluation, a set of the phenomenological event trees are developed, the headings of the master event tree is analyzed by using sub-event trees. The dominant factors to affect the branching ratio of the headings of the sub-event trees are identified together with the data base for quantitative probability evaluation.
SFR FBR ATWS Severe Accident Event Tree
Kazuya Koyama Yumi Yamada Osamu Watanabe Satoshi Hayakawa Motoko Watanabe Ryuzaburo Kubota Tohru Suzuki Kenji Kamiyama
Mitsubishi FBR Systems, Inc. 2-34-17, Jingumae, Shibuya-ku, Tokyo, 150-0001, Japan Mitsubishi FBR Systems, Inc.2-34-17, Jingumae, Shibuya-ku, Tokyo, 150-0001, Japan Japan Atomic Energy Agency4002 Narita-cho, O-arai, Ibaraki, 311-1393, Japan
国际会议
上海
英文
595-606
2010-10-10（万方平台首次上网日期，不代表论文的发表时间）