NSSC Approves Restart of Shinwolseong Unit 2

Appearance of Shinwolseong Units 1 and 2 (Photo by Korea Hydro & Nuclear Power)

[Asia Economy Sejong=Reporter Dongwoo Lee] Shinwolseong Unit 2 in Gyeongju, Gyeongbuk, will resume operation. It has been 12 days since it was automatically shut down on the 8th.

The Nuclear Safety and Security Commission (NSSC) announced on the 20th that it approved the restart of Shinwolseong Unit 2.

Previously, on the 8th, while operating normally, the output circuit breakers of two motor generators supplying power to the control rod drive mechanism were simultaneously opened, causing the control rods to drop and the reactor to automatically shut down.

According to the NSSC investigation, during the process of increasing the voltage of one motor generator, a failure in the variable resistor within the voltage adjustment switch caused a sudden drop in voltage, which led to the opening of the output circuit breaker.

After maintenance was completed and the motor generators were reintroduced, the voltages of the two generators were not synchronized, causing an overcurrent, which in turn caused the output circuit breakers of both generators to open simultaneously.

The NSSC explained that after the reactor automatically shut down, the nuclear power plant operators performed stabilization measures according to related procedures, and safety equipment functioned normally, confirming that there was no abnormal increase in radiation inside or outside the power plant.

The NSSC confirmed that there were no issues with the replacement of the faulty variable resistor, the motor generators, and the inspection of related equipment conducted by Korea Hydro & Nuclear Power (KHNP). KHNP has established plans including developing abnormal procedures for motor generators and strengthening work management for equipment failures causing transient states such as power shutdowns.

The NSSC stated, "After approving the restart of Shinwolseong Unit 2, we will closely monitor the power increase process and continuously check KHNP's implementation of recurrence prevention measures."

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