Hanul Unit 6 Resumes Operation After Scheduled Inspection...Nuclear Safety and Security Commission Confirms Criticality Safety

All Major Inspections, Including Coolant Pump, Structural Safety, and Leakage Tests, Show No Issues

Unit 6 of the Hanul Nuclear Power Plant, located in Uljin, Gyeongsangbuk-do, is set to resume operations after completing its scheduled inspection.

Panoramic view of Hanul Nuclear Power Plant, Uljin, Gyeongsangbuk-do.

On May 20, the Nuclear Safety and Security Commission announced that it had approved the restart of Hanul Unit 6 by granting permission for the reactor to reach "criticality."

"Criticality" refers to the state in which a sustained nuclear fission chain reaction is maintained within the reactor, marking a key phase in reactor operation. Once criticality is achieved, the reactor can be safely controlled and its output can be adjusted for power generation.

Hanul Unit 6 underwent a scheduled inspection that began on March 18, during which a total of 97 items were checked. Of these, all 87 items that were required to be completed before reaching criticality were successfully passed. The Nuclear Safety and Security Commission stated, "The inspection results confirmed that there are no safety issues with the reactor reaching criticality."

This inspection included the replacement of the reactor coolant pump motor, verification of leakage in the pump seal injection water, structural safety checks of the containment building, and replacement of the support for the equipment cooling water system pump. All items were found to meet safety standards.

The Nuclear Safety and Security Commission plans to conduct additional follow-up inspections, such as reactor power escalation tests, to finally confirm the safety of the reactor during the initial stages of operation.