Study on the structural integrity of RPV using PFM analysis concerning inhomogeneity of the heat-affected zone

Masaki, Koichi; Katsuyama, Jinya  ; Onizawa, Kunio 

In order to obtain the technical basis to judge the needs of surveillance test specimens from HAZ materials, the features of inhomogeneity of HAZ in RPV steels were investigated. Concerning on the fracture toughness in HAZ, HAZ materials close to weld metal indicated higher toughness than that of base metal due to high-toughness phase, while HAZ materials close to base metal were equivalent or slightly lower toughness than that of base metal due to the same phase as base metal. A structural integrity assessment method concerning such inhomogeneous distribution of fracture toughness for HAZ materials was developed and incorporated into PFM analysis code PASCAL3. Case studies on postulated flaws distribution and chemical composition were performed by using PASCAL3. It was shown that in highly irradiated conditions, CPI and CPF in HAZ close to weld metal are lower than base metal, while those in HAZ close to base metal were almost equivalent to base metal.