Comparison of the high Ni WER-1000 weld microstructure under the primary irradiation and re-irradiation

摘要

This paper presents the first comparative experimental assessment of the microstructures of the same surveillance specimens of VVER-1000 high Ni weld: after the primary irradiation, recovery annealing and re-irradiation in the same industrial NPP (Balakovo NPP unit 1) to assess the possibility of its lifetime extension after annealing up to 60 years. Therein, studies of both the initial (carbides) and radiationinduced hardening phases (precipitates and dislocation loops), and the behavior of grain boundary segregation as well are presented.