Development of Evaluation Method on Integrity of RPV at the Upper Shelf Region

In order to develop the integrity evaluation technology for aged major components of nuclear power plants, the Japan Power Engineering and Inspection Corporation (JAPEIC) has been carrying out the project named “Nuclear Power Plant Integrated Management Technology (PLIM)” entrusted by Japanese Ministry of Economy, Trade and Industry (METI) since 1996Fiscal Year (FY). One of the objectives of this project is to establish the method for integrity evaluation of aged domestic reactor pressure vessels (RPV) by developing the prediction equations of reduction of Charpy V-notch Upper Shelf Energy (USE) due to neutron irradiation embrittlement and the correlation equations between USE and fracture toughness. Because the tests are now in progress, this paper presents the following preliminary results as of the end of 2000FY, using irradiated Charpy and Compact Tension specimens of RPV materials. • Study on the effect of accelerated irradiation for test specimens. • Comparison of USE values between test results and U.S. surveillance data. • Comparison of USE values between test results and published predictions. • Correlation between USE value and fracture toughness.