METHOD AND SENSOR FOR MONITORING NUCLEAR POWER PLANT

PROBLEM TO BE SOLVED: To make it possible to easily predict the degree of sensitization or the water quality of in-vessel materials without the necessity of large-scale test facilities. SOLUTION: Crack occurrence limit curves 10 to 14 are found beforehand for various kinds of the degrees of sensitization or water quality conditions of test pieces 1 constituted of the same ingredients as in-vessel materials in a nuclear reactor. Then, a monitoring sensor 3 with test pieces 1 similar to those used to find the crack occurrence limit curves is loaded in the reactor and is taken out to measure the crack sensitivity after it has been irradiated for a prescribed time. Measurement values 17 and 18 of the crack sensitivity are applied to the crack occurrence limit curves 10 to 14 to predict the degree of sensitization or the water quality of in-vessel materials in a reactor at positions where the test species 1 are loaded.