The shutdown of the No. 1 nuclear reactor at the Wolseong power station on Monday was the result of human error, Korea Hydro and Nuclear Power said Tuesday. It said a plant operator made a mistake while manipulating a circuit breaker, causing a power shortage to some equipment which led to a malfunction in the cooling system.
"An internal probe revealed that a senior employee handed over his responsibilities to a junior with only two years of experience, who misunderstood his orders and operated the wrong switch," a KHNP staffer said.
This is similar to the mistake that caused a malfunction at reactor No. 1 at the Gori nuclear power station that led to a blackout in February. At that time, a subcontracted worker with little experience failed to follow procedure and pushed the circuit breaker, causing the entire nuclear plant to lose power for 12 minutes.
"Human error is a more serious problem than faulty components and is the result of a lack of safety awareness," said Prof. Hwang Il-soon at Seoul National University.
The latest incident appears to spell the death warrant for the Wolseong No. 1 reactor, which reaches the end of its 30-year life cycle on Nov. 20. A KHNP official said an inspection revealed serious damage to the inside of the reactor and a detailed probe will take place after the reactor is dismantled. The inspection will take more than a month.