DIAGNOSTIC METHOD, DIAGNOSTIC APPARATUS AND REPAIR METHOD OF NUCLEAR REACTOR STRUCTURE

摘要

PROBLEM TO BE SOLVED: To provide a diagnostic method of a nuclear reactor which is effective for extension of the life and preventive maintenance of the reactor and enhances reliability of the reactor by enabling repair welding of a reactor structure subjected to neutron irradiation. SOLUTION: The diagnostic method is used for diagnosing whether or not the reactor structure having a metallic material with a possibility of producing helium upon neutron irradiation can be welded. The method comprises processes 10 and 11 of obtaining the helium content of a diagnosis object material 9 constituting the reactor structure, estimation processes 17 and 18 of estimating the number of welding passes contributing to production of grain boundary helium bubbles by planned welding of the diagnosis object material and a diagnosing process 19 of diagnosing whether welding of the material is permitted or not on the basis of the helium content of the material, the number of the welding passes contributing to the production of the grain boundary helium bubbles and heat input by the planned welding. The process of obtaining the helium content comprises the steps of taking a small volume of a sample from the material and measuring the helium content contained in the sample. COPYRIGHT: (C)2004,JPO