A large bore carbon steel pipe of a PWR secondary system ruptured in Mihama 2 with some victims in 2004. The Japan Society of Mechanical Engineers (JSME) established the rules for pipe-wall-thinning management by 2006 under the Main Committee on Power Generation Facility Codes (MC-PGFC) to prevent such pipe ruptures. The rules cover the entire system of pipe-wall-thinning management including determining the pipeline to be inspected, the timing and the methods of inspection, evaluation of remaining period for fit for service, and repair and replacement of pipeline. Since the rules were established in a short term, some issues were pointed out to enhance the rules such as a screening method of inspection points, prediction methods of thinning rate, inspection methods, repair methods, etc. Improvement of the rules is one of the major issues in many of organizations. In this note, the roadmap of R&Ds to enhance the rules is described, which MC-PGFC established in 2007, and revised in research committee continuously in JSME.
