The government shut down unit 5 and unit 6 of the nuclear power plant in Yeonggwang County, South Jeolla Province, on Monday, after finding a number of “substandard” components in the two nuclear reactors.

The government’s announcement of the use of unapproved parts in the nuclear power plants shocked the public, raising concerns over safety and power shortages during the upcoming winter.

Speaking at a press briefing, Knowledge Economy Minister Hong Suk-woo said eight part suppliers have faked 60 warranties for 234 parts since 2003 and so supplied 7,682 unqualified items worth 820 million won ($750,000) to the Korea Hydro & Nuclear Power Co., KHNP, the state-run operator of the nation’s 23 nuclear reactors nationwide.

Of the total substandard items, 5,233 have actually been installed in five nuclear reactors and about 99 percent of them were used in unit 5 and unit 6 of the nuclear power plant in Yeonggwang, which is located some 330 kilometers southwest of Seoul.

Minister Hong said, “The ministry decided to shut down the two reactors as part of preventive measures. The two reactors will continue to be stopped until the replacement of poor parts is completed by the end of this year.” He added that the ministry will exchange faulty parts of three other reactors, while operating them.

The ministry claimed that it hadn’t found any evidence for a possible radiation leak due to the use of unqualified parts.

Ministry officials said an anonymous outsider tipped them off with the information on the use of unqualified parts at the end of October. It is not clear yet that the KHNP has been directly involved in the scandal.

The closure of the two nuclear reactors for more than a month is expected to deal a blow to the nation’s power supply in winter, given the fact that both are reactors with the capacity of generating one million kilowatts per hour.

Industry watchers said a partial blackout is a possible scenario in January and February next year, if the resumption of the closed two reactors is pushed back to early next year or other reactors are also shut down.

Nuclear power plants are one of the major power sources in Korea, taking about 30 percent of the nation’s total power generation.

As a follow-up measure to cope with the power supply in the winter, the ministry said it has launched a contingency team and will soon discuss measures with businesses consuming massive power.

The ministry is also under fire for its mismanagement of nuclear power plants due to a series of breakdowns. Nine cases, including those of unit 5 and unit 6 of the nuclear plant in Yeonggwang, have been reported this year, a hike from 4 cases from a year earlier.

Nuclear-related businesses also raised concern over the impact of the incident on their exporting business. Korea has sought to become a major world nuclear energy country, exporting its technology. It won a $20 billion contract to supply four nuclear reactors to UAE last year.

By Seo Jee-yeon (jyseo@heraldcorp.com)