| 摘要 |
PROBLEM TO BE SOLVED: To provide a noble metal coverage monitoring method which can calculate a noble metal coverage in a surface of a structural member of an atomic power plant more accurately during the operation of the atomic power plant.SOLUTION: An action electrode and a counter electrode are arranged in a branch pipe attached to a pipe (structural member) which is connected to a reactor pressure vessel and through which a coolant flows. The AC impedance between the action electrode and the counter electrode in contact with the coolant is measured during the operation of the atomic power plant (S1). An area of a noble metal coating part of the electrode surface is calculated on the basis of the measured AC impedance, and a noble metal coverage of the electrode, which is a pipe inner face, is calculated using the area (S2). A determination is made as to whether the noble metal coverage is less than a reference value (S3), and when the noble metal coverage is less than the reference value, injection of the noble metal is started (S4). At the time of the injection of the noble metal, measurement of the AC impedance (S5) and calculation of the noble metal coverage (S6) are performed, and when the noble metal coverage is not less than a target value, the injection of the noble metal is stopped (S8). |
