Unplanned shutdown frequency prediction of FBR MONJU using fault tree analysis method

FTAによる「もんじゅ」計画外停止頻度評価

素都 益武 

Sotsu, Masutake

「もんじゅ」の冷却系統,安全保護系、プラント制御設備に対し、原子炉トリップを頂上事象としたフォールトツリー解析を実施した。その結果、機器故障に起因して原子炉トリップに至る発生頻度及び中間事象と機器故障の寄与割合を適切に評価し、トリップ低減策の効果を確認した。

In order to evaluate the operational reliability of Japanese fast breeder reactor MONJU, frequencies of important intermediate events and equipment failures resulting during reactor automatic trip are predicted using fault tree analysis technique for the plant system model. The targeted devices are the following: primary heat transport system (PHTS), secondary heat transport system (SHTS), water and steam system (WS), plant protection system (PPS) and plant control system (PCS). In this paper was estimated the frequency of automatic reactor trips by extracting and analyzing the important intermediate events and equipment failures covering all the derived fault trees of these systems. The analyses predicted 1.2/reactor year (RY) the value of unplanned shut down frequency by the internal factor of the system.