Concerns about the safety of the nuclear reactors in Korea are growing as problems arise in succession at the reactors of the Gori nuclear power plant near Busan.

The Gori-1 reactor, the oldest in Korea, which started operation in 1978, shut down on April 12 after a fire destroyed one of its circuit breakers. At first, Korea Hydro & Nuclear Power Co. said a defective power switch caused the power failure. But later, the Korea Institute of Nuclear Safety said defects were found in the circuit breaker. Now some suspect that there might be more fundamental safety problems that go beyond a circuit breaker malfunction.

To address these concerns, KHNP said on Wednesday it would temporarily halt the reactor for a thorough check and resume its operation only after safety has been confirmed. The operator’s failure to identify the cause of the problem fueled calls from Gori residents to shut down the reactor, whose life was extended for 10 years in 2008 after it reached its initial 30-year lifespan.

On Tuesday, an accident occurred at the Gori-4 reactor. KHNP said an engineer who was inspecting the Gori-3 reactor, which was shut down on April 4 for regular maintenance, touched the electric cable that supplies power to the Gori-3 unit, thinking that power was cut off. But this stopped power supply to the Gori-4 reactor because the cable also supplied power to it. The power cutoff activated a backup diesel generator, keeping the Gori-4 unit online.

The accident did not halt the operation of the Gori-4 unit but showed that the plant design was faulty. One design principle for a nuclear plant is that power is supplied to separate reactors through different cables to ensure that the reactors do not go offline simultaneously when an electrical system failure occurs at one of them. The Gori plant failed to follow this principle.

The accidents at the Gori reactors showed that they have safety problems ranging from plant design to reactor parts. Therefore it is necessary for the government, KHNP and KINS to review the safety of the 21 nuclear reactors in Korea from the ground up and take steps to ease the public’s concerns. Otherwise, they would face a rise in anti-nuclear sentiment.