Vessel failure sensitivities of an advanced reactor for SBLOCA

Abstract

Plant-specific analyses of an advanced reactor have been performed to assure the structural integrity of the reactor pressure vessel during transient conditions, which are expected to initiate pressurized thermal shock (PTS) events. The vessel failure probabilities from the probabilistic fracture mechanics analyses are combined with the transient frequencies to generate the through-wall cracking frequencies, which are compared to the acceptance criterion. Several sensitivity analyses are performed, focusing on the orientations and sizes of cracks, the copper content, and a flaw distribution model. The results show that the integrity of the reactor vessel is expected to be maintained for long-term operation beyond the design lifetime from the PTS perspective using the design data of the advanced reactor. Moreover, a fluence level exceeding 9✕1019 n/cm2 is found to be acceptable, generating a sufficient margin beyond the design lifetime. Keywords: Reactor pressure vessel(RPV), Pressurized thermal shock(PTS), Failure probability, Small break loss of coolant accident(SBLOCA)