G0310404 Development of fracture toughness curves for Japanese reactor pressure vessel steels

Abstract

Structural integrity of reactor pressure vessel (RPV) is evaluated according to the Japan Electric Association Code JEAC4206 "Method of Verification Tests of the Fracture Toughness for Nuclear Plant Components" in Japan. In the current code, the fracture toughness curve for evaluation against pressurized thermal shock (PTS) phenomenon shall be constructed for each plant so that it envelopes all the fracture toughness data obtained from surveillance tests and adjusted to the end of plant operation term. Through this activity, a large number of irradiated fracture toughness data have been accumulated for Japanese RPV materials. In this study, fracture toughness curves for Japanese RPV materials depending on product form that employ master curve concept are developed. The curves are intended to represent 5% lower tolerance bound of fracture toughness trend with incorporating fracture toughness variation of each product form.