Unit 3 of the Saeul Nuclear Power Plant in Ulju, Ulsan, which automatically shut down during a commissioning test, stopped again two days after restarting. This time, a leak was found in the steam condensate drain piping, and operators manually shut down the reactor.
Korea Hydro & Nuclear Power Co. (KHNP) Saeul Nuclear Power Headquarters said it manually shut down the 1.4 million-kilowatt Saeul Unit 3 reactor at 3:01 p.m. on the 6th.
The step followed confirmation of a leak in the piping that drains steam condensate supplied to the turbine. Saeul Nuclear Power Headquarters said it shut down the reactor to stabilize and service the equipment.
Saeul Nuclear Power Headquarters said there was no radiological impact from the shutdown and the plant remains stable. The exact cause of the leak is under investigation.
Saeul Unit 3 had previously shut down automatically on the 11th of last month during commissioning. At the time, after completing a test to cut power transmission at 80% reactor output and while restoring output, an operator entered an incorrect set value for the turbine control valve position limiter, which was identified as the cause.
The Nuclear Safety and Security Commission approved the resumption of commissioning for Saeul Unit 3 on the 4th after completing its review.
Saeul Unit 3 has been conducting step-by-step power-raising commissioning tests ahead of commercial operation since receiving its operating license from the Nuclear Safety and Security Commission in Dec. last year.