原子炉内表面に発生した孔食の溶接補修
概要
Hamaoka nuclear power plant unit-5 had the sea water intrusion incident in 2011 during the shut-down process. We, Chubu electric power company, have conducted some researches for unit-5 re-start, since we had some concerns about the aftercare of pitting corrosions occurred in the inner surface of RPV. The aftercare includes the determination of whether corrosion pitting might propagate until RPV, determination of whether or not to clean Chloride ions in corrosion pits and the determination of need for weld repair of corrosion pitting after the precise location confirmation by ECT or some other non-destructive method. This report summarize the fundamental weld repair methodology, especially for the necessity of temper beads welding from the view point of hardness and residual stresses, for application against RPV. The computer simulation had been mainly done as a first attempt for the purpose of the resource reduction.
