Prediction of radiation embrittlement for highly irradiated reactor vessel steels, 6; Study on integrity assessment method based on probabilistic fracture mechanics

Onizawa, Kunio ; Matsuzawa, Hiroshi*

Concerning the structural integrity analysis method for aged reactor pressure vessel (RPV) during pressurized thermal shok (PTS) event, a probabilistic analysis approach has been investigated. Based on the survey on the proposed revision of the PTS rule in USA and the revision of radiation embrittlement prediction equation in Japan, probabilistic analyses of RPV integrity were performed using probabilistic fracture mechanics (PFM) analysis code PASCAL2. The effects of major factors affecting the integrity such as crack existing probability, radiation embrittlement prediction equation, fracture toughness equation have been studied. From the comparison of analysis results by deterministic and probabilistic methods, it was shown that the transient loading had little effect on the correlation between deterministic safety margin and corresponding probabilistic fracture probability.