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

Sotsu, Masutake 

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.