Results of periodical inspection in 1979 FY of Tsuruga Nuclear Power Station of Japan Atomic Power Company

The 10th periodical inspection in 1979 FY of the Tsuruga Nuclear Power Station of the Japan Atomic Power Company was conducted from March 24 to July 25, 1979, through 124 days. The inspection items were the inservice inspection of the reactor coolant pressure boundary, fuel inspection, the margin of control rods checkup of in-reactor shut down, the inspection of the main steam safety valve, the leak checkup of the main steam isolation valve, the functional chekup of the control rod-driving mechanism, the inspection of the reactor protection system, the checkup of the radiation monitoring system, the leak test of the containment vessel, the automatic start up test of emergency diesel engines and the overall interlock inspection, etc. The inspection results are presented for each inspection item. No abnormality was found in this inspection. The additional items were also inspected in consideration of the TMI accident, such as the ECCS, the feed water system and the motor-driven valves, and it was confirmed that these systems and components are completely sound. The mean exposure doses for the employee of the company and contracted workers were 0.35 rem and 0.36 rem, and at maximum 1.25 rem and 1.93 rem respectively, during the inspection time. No abnormality was found in the internal exposure measurement utilizing a whole body counter. Some modifications of construction work, for example, the countermeasures to stress corrosion cracking and the replacement of neutron detectors with reduced sensitivity, were conducted. The inspection schedule is presented. (Nakai, Y.)