NSSC Approves Restart of Shinori Unit 1 Reactor

[Sejong=Asia Economy Reporter Kwon Haeyoung] The Nuclear Safety and Security Commission completed the investigation and safety verification of the manually shut down Shin-Kori Unit 1 incident on the 11th and approved its restart on the 23rd.

On the 8th of this month, during normal operation of Shin-Kori Unit 1, the differential relay for phase B of the generator trip line operated, causing the turbine and generator to stop and the reactor output to decrease to 45%. Accordingly, Korea Hydro & Nuclear Power (KHNP) manually shut down the reactor on the 11th after the holiday to replace the damaged equipment.

The investigation revealed damage to the gas-insulated busbar (GIB) high-voltage bushing of phase B in the generator trip line of Shin-Kori Unit 1. The cause of the damage was identified as overheating and melting due to poor contact at the internal connection point (between the conductor and contact) of the high-voltage bushing.

The NSSC stated, "Replacement of the damaged high-voltage bushing, inspection of the generator trip line equipment, and improvements to maintenance procedures and standards have been completed." They added, "After approving the restart of Shin-Kori Unit 1, we will monitor the output recovery process and continuously check KHNP's implementation of recurrence prevention measures."