Status on the revisions of standards related to fracture toughness evaluation for light water reactors in Japan

In Japan, requirements associated with fracture toughness evaluation for light water reactors are specified in the MITI (Ministry of International Trade and Industry) Code and the industrial standards issued by the JEA (Japan Electric Associations). Design and fabrication requirements on the material, reactor pressure vessel surveillance program, pressure temperature limits imposed on the components both during normal and accident conditions are defined therein and design and operation of the light water power plant components are conducted in accordance with these codes and standards. This paper explains the major features of existing standards, the recent activities of the revisions and the new technologies unique to Japan to be incorporated. Those are various equations on fracture toughness based on the Japanese research and development results, and the new proposal on the withdrawal schedule of the surveillance capsule from the cores of reactor pressure vessels. (author)