INTERNAL MECHANICAL STRESS IMPROVEMENT METHOD FOR MITIGATING STRESS CORROSION CRACKING IN WELD AREAS OF NUCLEAR POWER PLANT PIPING

摘要

Method for mitigating stress corrosion cracking at an internal (i.e., wetted-side) weld area in piping of a nuclear power plant includes the steps of actuating a radially movable tool to produce a radial load against the internal (i.e., normally wetted) surfaces at or near the weld area to create a deep residual compressive stress state at the wetted surface of the weld. The method permits post-process verification by physical measurements of surface distortion.