NSSC Approves Restart of Kori Unit 2 Reactor

NSSC Concludes Investigation of Gori Unit 2 Incident
Operation Halted on 3rd This Month Due to Circuit Breaker Issue
KHNP Plans to Review Recurrence Prevention Measures

A panoramic view of the Gori Nuclear Power Plant located in Gijang-gun, Busan. [Image source=Yonhap News]

[Asia Economy Sejong=Reporter Lee Jun-hyung] The Nuclear Safety and Security Commission approved the restart of the Gori Unit 2 nuclear power plant, which was shut down on the 3rd of this month.

The NSSC announced on the 29th that it had completed the investigation of the Gori Unit 2 incident and approved its restart. Earlier, around 6 p.m. on the 3rd of this month, Gori Unit 2 automatically shut down its turbine, generator, and reactor due to a problem with the circuit breaker supplying power to non-safety equipment. The NSSC had been conducting safety verification procedures through an investigation of the incident.

The NSSC's investigation found that the automatic shutdown of Gori Unit 2 was caused by misalignment at the circuit breaker connection point. Korea Hydro & Nuclear Power (KHNP) did not align the connection points when replacing the circuit breaker twice, in 2010 and 2018, because there was no separate standard provided by the circuit breaker manufacturer.

The NSSC considers it unlikely that the cause of the automatic shutdown was equipment aging, as the circuit breaker, which has a replacement cycle of 20 years, was already replaced in 2018. It was also confirmed that the transformer circuit breaker operated due to abnormal current caused by the circuit breaker issue, which triggered the automatic operation of the emergency diesel generator.

The NSSC judged that the Gori Unit 2 operators did not violate related procedures during their response to the automatic shutdown incident. According to the NSSC, the safety equipment of Gori Unit 2 operated normally, and radiation levels inside and outside the plant did not exceed normal values. The NSSC also stated that KHNP’s soundness inspection of the plant equipment was appropriately conducted.

KHNP conducted inspections of major equipment to ensure the reliability of Gori Unit 2 at the request of the NSSC. The NSSC plans to continuously monitor KHNP’s implementation of recurrence prevention measures.

This content was produced with the assistance of AI translation services.