Knowledge survey based on published works in the area of WWER reactor pressure vessel steels microstructure

The effects of intensive fluxes of neutrons, thermal ageing or other external factors result in considerable changes of material microstructures and properties. In particular, the development of the fine scale radiation-induced defects which impede the dislocation motion under the applied stress, known as the irradiation embrittlement, leads to mechanical properties degradation which can results to the partial loss of plasticity and to the increase of brittle fracture. Defects are formed from vacancies and interstitials created in collision cascaded processes. With the aim to reveal processes connected to WWER pressure vessel steel degradation, the importance of experimental microstructural studies was accented in many comprehensive works during the last 40 years. Many of these investigations resulted in valuable findings used worldwide. This paper is focused on the survey of knowledge extracted from relevant papers in area WWER steel microstructure selected by group of experts in frame of EC framework projects 'Nuclear Knowledge Preservation & Consolidation' coordinated by JRC Petten.

Keywords: reactor pressure vessels, RPV steel, WWER reactors, steel microstructure, material testing, spectroscopic methods, nuclear power plants, NPP, nuclear energy, nuclear safety, safety assessment, irradiation embrittlement, plasticity, brittle fracture, nuclear knowledge management