Study of Relational Equation between Indent For Cable Aging Evaluation

Attempts to extend the lifetime of NPP have become one of the major concerns in the world nuclear industry. Consequently, life evaluation and lifetime management of cable to survive over 40 years has become major topic of discussion. For the life extension of nuclear power plant, two kinds of actions are required in accordance with regulatory rule of plant life extension. One is TLAA(time limited aging analysis) and the other one is AMP(aging management program). TLAA is an evaluation of residual life to insure the survival during the extended period. AMP is a monitoring of aging degradation to insure that aging degradation does not go beyond the allowable limit during extended period. For the life evaluation of cable, break-elongation test of ASTM D412 has been widely used. Since dumbbell specimen for break-elongation test has to be supplied from plant cable, it is not easy to apply this method to operating plant. One of alternatives is indent test which nondestructively measures the aging of cable jacket. Because indent test has no approved standard, we have to compare the test result with that of break-elongation test. Since two kinds of tests for one aging evaluation are time consuming, we decided to develop relational equation between elongation and indent which can deliver relative elongation value from indent data. Relational equation between elongation and indent based on the actual test results of CSP and CR cable jacket is described herein