Noto Peninsula Earthquake: Nuclear Plant Equipment Verification

This document details the verification of power plant equipment failures and malfunctions at the Shiga Nuclear Power Station following the Noto Peninsula earthquake on January 1, 2020. The Atomic Energy Council, through the Knowledge Sorting SWG, examined cases including transformer oil leaks and pressure relief plate operations, emergency diesel generator automatic stoppage during trial runs, spent fuel storage pool equipment falling, control rod drive housing support fittings detaching, campus road subsidence, seawall tilting, and pure water tank leakage. The study aimed to derive lessons learned and propose measures for voluntary safety improvements. Key findings include that transformers experienced accelerations beyond seismic design but redundancy in external power sources was effective; for transformers, early recovery measures and shutdown procedures for oil leaks are recommended. For D/Gs, preventing automatic stops during parallel operation is emphasized. SFP items should be secured to prevent foreign material intrusion. CRD housing support fittings require structural reviews to prevent parts falling. Campus road and seawall issues were addressed with existing measures, while pure water tank leaks highlighted the need for piping inspections. Overall, the document reinforces the importance of redundancy and proactive safety enhancements in nuclear plant equipment.