Research and Surveillance Activities for the Improvement of Pipe Wall Thinning Management

(6. Examples of Local Thinning Analysis based on ASME Code Case N-597-2 and Future Issues to be introduced into Pipe Wall Thinning Management in Japan)

Abstract

Many overseas countries adopt local thinning criteria that calculate minimum thickness according to the thinning area because pipe wall thinning phenomena caused by flow accelerated corrosion (FAC) and liquid drop impingement (LDI) decrease pipe wall thickness locally. On the other hand, power generating facilities codes in Japan adopt conservative criteria that postulate general thinning. Now the introduction of reasonable pipe wall thinning management that adopts local thinning criteria is highly expected. In Japan Society of Mechanical Engineers (JSME), Management Rule Revision Working Group has been held under the research committee for the improvement of pipe wall thinning management and reviews the application of update knowledge to pipe wall thinning management. This paper introduces the study of domestic and overseas codes that adopt local thinning criteria, the examples of local thinning analysis applying these codes and future issues to adopt local thinning criteria in Japan.