As President Park Geun-hye said recently, it is an unpardonable crime to compromise safety in nuclear power generation in pursuit of personal gain. What kind of catastrophe a nuclear accident can inflict on a nation has been shown by the Chernobyl and Fukushima disasters.

Prime Minister Chung Hong-won shared the president’s deep concern about nuclear safety when he promised on Friday to leave no stone unturned in the government’s investigation into the provision of substandard parts and materials for nuclear power plants.

Now targeted for criminal investigations are those that are found to have been involved in falsifying test certificates for parts and materials used in nuclear power plants. They have put the nation under the threat of nuclear hazards by trading nuclear safety for their personal interest. None of them will deserve even an iota of leniency.

In the center of the case is Saehan Total Engineering Provider Co., better known as Saehan TEP, which is suspected of forging test certificates for parts used in six reactors that recently were shut down. The government has started an investigation into the company that certified the signal cables manufactured by JS Cable, which were found to be faulty and caused the shutdown of two nuclear reactors last month.

Document forgery is not believed to be limited to the test certificate for JS Cable’s signal cables, given the government’s promise to inspect 125,000 test certificates that have been issued for parts and materials used at every nuclear power plant in the nation.

The government says the inspection will be completed in two or three months. It must not rush it, given that no shoddy work can be permitted here as well. Instead, it will have to take more time, if necessary, to examine the certificates.

Then the prosecution will undoubtedly throw out a dragnet to haul in all criminal suspects in a war that the prime minister declared against the corruption that he believes has permeated the entire nuclear power industry. But bringing all criminal suspects to justice will not be enough to ensure nuclear safety.

No less dire is the need to break up an old boy network, dubbed the “nuclear power mafia,” which constitutes a chain of corruption in the nuclear power industry. When they quit, many executives of state-run organizations and corporations involved in nuclear power generation find jobs at companies providing parts and services for nuclear reactors. Moreover, some of them reportedly hold shares of Saehan TEP.

In this regard, the government is called on to pay keen attention to remarks made by Kim Kyun-seop, who resigned from the post of chief executive officer of Korea Hydro & Nuclear Power Corp. earlier in the week. He told a news outlet he faced strong resistance from the old boy network when he pushed for reform upon his inauguration. He said it is urgent to put it under tight control.