The Comprehensive Discussion of the Pipe Wall Thinning of Secondary System in BWR and PWR Nuclear Power Plants

The behaviors of pipe wall thinning of secondary systems in The Japan Atomic Power Company (JAPC)’s BWR and PWR nuclear power plants were compared in this paper, to discuss the effects of respective factors contributing to corrosion protection of pipe. The rates of pipe wall thinning in single-phase flow environment, in both BWR and PWR, depend on temperature. Nevertheless, the rate of pipe wall thinning in PWR is more than that in BWR. The rates of pipe wall thinning at elbow of pipe, bending of pipe, straight run of pipe and reducer areas are mutually different, although they are located in the same line. Especially, the rates of pipe wall thinning at elbows of pipes, bendings of pipes, straight runs of pipes and reducers, which are located closely downstreams of the pumps discharge nozzles, elbows, orifices or bent pipes, depend on not the temperature but the pipe configuration.