Results of evaluation of periodic safety review for No. 1 plant in Mihama Power Station, Kansai Electric Power Co., Inc

No. 1 plant in Mihama Power Station started the commercial power generation in November, 1970, and has continued the operation for more than 23 years. During this period, the counter measures to troubles, periodic inspections and the maintenance by the electric power company have been carried out. These states of No. 1 plant in Mihama Power Station for more than 23 years are to be recollected from the view-points of the comprehensive evaluation of operation experiences and the reflection of latest technological knowledge, and the safety and reliability are to be further improved in the periodic safety review. Agency of Natural Resources and Energy evaluated the report of the periodic safety review for No. 1 plant in Mihama Power Station made by Kansai Electric Power Co., and summarized the results. The course of the evaluation of the report is shown. The facility utilization factor is 43.3% on the average of about 23 years, but in the last 10 years, it was improved to 69.4%. In the last five years, the rate of occurrence of unexpected shutoff was 0.6 times/year. These are the results of preventive maintenance and the improvement of the facilities and operation management. Operation management, maintenance management, fuel management, radiation control, and radioactive waste management have been carried out properly. The work plan for preventing disasters was established, and the experience of troubles and the latest technological knowledge were well reflected to improve the safety. (K.I.)