Irradiation embrittlement monitoring procedures and results of reactor pressure vessels of the WWER type

Abstract

This paper describes part of a knowledge preservation programme coordinated by JRC Petten. The following issues are discussed and analysed: comparison of surveillance specimen results from WWER-440 and 1000 units; surveillance specimen programme modernisation based on the new philosophy and approaches; the efficiency of Reactor Pressure Vessel (RPV) steel annealing by implementation of procedures such as boat sampling, instrumented hardness, neutron diffraction, positron annihilation, etc.; the analyses of irradiated samples from RPV materials by modern methods; the irradiation embrittlement of the RPV weld metal due to the effects of impurities; the evaluation of RPV irradiation embrittlement trends during planned LTO; critical analyses of existing rules and codes, used by lifetime evaluation; theoretical models which may more or less describe the influence of impurities in RPV steels; evaluation of impact and toughness test results by implementation of the 'master curve approach'.