Keywords: nuclear knowledge preservation, surveillance specimen programme, WWER 440 units, WWER 1000 units, databases, annealing, RPV steel, reactor pressure vessels, water chemistry, cladding, fracture toughness, embrittlement modelling, irradiation embrittlement, embrittlement monitoring, nuclear knowledge management
Irradiation embrittlement monitoring procedures and results of reactor pressure vessels of the WWER type
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'.