CHANGE IN SYSTEM OPERATION OF RESIDUAL HEAT REMOVAL SYSTEM BASED ON THE RESULTS OF SPENT FUEL POOL TEMPERATURE EVALUATION AT HIGASHIDORI NUCLEAR POWER STATION

Abstract

As a result of the planned suspension of cooling of the spent fuel pool at Unit 1 of the Higashidori NPS, the water temperature was in good agreement with the evaluation results from the temperature evaluation model, and was stabilized at the temperature well below the limit value specified in the safety regulations. Based on the results, the impact on the plant when the residual heat removal system, which was on standby as a backup of the fuel pool cooling system during the long-term outage, is put out of standby, was evaluated, and it was confirmed that the impact would be small. Therefore, we reviewed the operation of the residual heat removal system and optimized the maintenance tasks. Through these activities, we are able to reduce the number of regular tasks and allocate management resources to more important tasks.