The root cause of the suspension of two nuclear reactors and the resulting electricity shortage was faulty control cables, which may have led to a radiation leak in the worst case scenario, according to the Nuclear Safety and Security Commission.

The disputed cable is a safety feature, intended to deliver action signals to the nuclear reactor’s cooling and shut-off system when an abnormality is detected.

“Should these cables fail to perform their function, the possibility of a radiation leak may not be excluded,” said the commission through its report.

The initial report on the faulty parts was first submitted in April through the NSSC website.

After an independent probe, the commission concluded that substandard cables were delivered to the Shin-Kori Reactor 2 in Busan and Shin-Wolsong Reactor 1 in North Gyeongsang Province, and that their test certificates were forged.

While suspending the two reactors, the organization also put the brakes on the start-up of the Shin-Kori Reactor 1, which had been undergoing maintenance, and the launch of the new Shin-Wolsong Reactor 2, which was facing imminent operation.

The parts suppliers, after failing to pass the given quality test, forged the certificates by copying the test reports issued by overseas nuclear-related organizations, officials said.

“The pressure durability of the cables fell below standards, but the suppliers manipulated the test graphs and their written reports,” said the commission’s report.

The commission also pledged to investigate further for possibilities of similar cases in the past.

President Park Geun-hye, too, demanded a thorough examination and preventive measures.

“We should clarify where the responsibility lies and take the due measures, so that this kind of accident never occurs again,” she said during a Cabinet meeting on Tuesday.

The ruling Saenuri Party also claimed that the Board of Audit and Inspection should participate in the investigation, in order to promote the transparency of the process.

In response to the blame, the Ministry of Trade, Industry and Energy once again offered its apologies and promises for restoration.

“We are sorry to have caused concern to the people once again with nuclear reactor issues,” said Han Jin-hyun, vice minister in charge of energy, at the parliamentary emergency council on Wednesday.

“I will strictly deal with the punishment and the prevention issues so that no doubts will remain any more.”

The vice minister on Tuesday kicked off a special task force, aiming at responding to the sudden shutdown and expected shortage of electricity in the upcoming summer season.

By Bae Hyun-jung (tellme@heraldcorp.com)