Breakdown and trouble in nuclear power stations in fiscal year 1987

The breakdown and trouble reported by electric power companies to the Agency of Natural Resources and Energy in conformity with the Electricity Enterprises Act and the law on the regulation of nuclear reactors and others were 19 cases. On the other hand, since the number of nuclear power stations increased, the average number of report per plant decreased slightly to 0.5. As to the breakdown of 19 cases, the automatic stop during operation was 4 cases, the manual stop during operation was 7 cases, the troubles discovered during the shutdown of reactors in regular inspections were 6 cases, and others were 2 cases. The main causes were classified into improper manufacture management (4 cases), improper construction management (3 cases), improper maintenance management (8 cases) and others (4 cases). In all cases, the effect of radioactivity to the surrounding environment of nuclear power stations did not arise. The Agency of Natural Resources and Energy is to maintain and improve the high reliability of present nuclear power generation, and to exert efforts to promote the technical development and improvement of LWRs, to utilize the information on operational experience including breakdown and trouble, and to maintain and improve the quality of operators and maintenance workers. The change of the number of the reports based on the laws and the outline of breakdown and trouble are shown. (K.I.)