Determination of crack growth resistance characteristics of 15Kh2NMFA-A steel minispecimens

Reliable operation of a NPP requires ensuring the integrity of the reactor pressure vessel (RPV) in all operating conditions. RPV life assessment is based on calculations of brittle fracture resistance. The key RPV problem is metal degradation due to irradiation, which leads to embrittlement and reduced crack growth resistance. This process is monitored using surveillance specimens which are kept in the reactor and periodically removed for testing. Traditionally, determination of RPV crack growth resistance requires standard specimens testing, but the limited availability of irradiated material complicates this process. The use of miniature specimens is a relevant solution. New results were obtained for the fracture toughness testing of 15Kh2NMFA-A steel using miniature C(T)0.16T specimens. It is shown that the test results allow predicting the reference temperature of the steel according to Master-curve.