Keywords: reactor pressure vessels, RPV materials, VVER, yield strength, DBTT, ductile-brittle transition temperature, tensile specimens, Charpy specimens, DBTT shift, RPV embrittlement, nuclear reactors, tensile strength, RPV steels, literature review, WWER
Mechanical property changes of VVER RPV materials embrittlement (tensile-Charpy properties)
Tensile strength and Ductile-Brittle Transition Temperature (DBTT) are the essential parameters for the strength analysis of reactor pressure vessels at various stages of operation, as well as for the validation of the lifetime extension. This paper reviews the changes in yield strength and DBTT under irradiation on the example of the Russian RPV steels: VVER-440 (15KhMFA steel and welds) and VVER-1000 (15Kh2NMFA steel and welds) as well as the functional dependences, developed in the last 10?15 years, to determine the DBTT of VVER RPV steels. The review is based on papers selected by a group of experts under the EC Project 'Nuclear Knowledge Preservation and Consolidation', coordinated by JRC Petten.