By Meeyoung Cho
SEOUL (Reuters) - South Korea said on Tuesday it was suspending the operations of two nuclear power reactors and extended a shutdown of a third to replace cables that were supplied using fake certificates, threatening power shortages in Asia's fourth-biggest economy.
The government warned there could be "unprecedented" electricity shortages and rolling blackouts this summer due to the nuclear shutdowns. South Korea previously halted the operations of some of its 23 reactors last November after a scandal emerged over parts being supplied using fake documents.
The Asian country is heavily dependent on oil, gas and coal imports, but usually gets about a third of its electricity from nuclear power generation.
"This is a separate case from the last investigation," said Kim Kyun-seop, president & CEO of Korea Hydro and Nuclear Power Co Ltd, which runs nuclear reactors in South Korea and is owned by state-run utility Korea Electric Power Corp.
The new case relates to forged documents on cables worth 6 billion won ($5.35 million) provided in 2008, Kim and energy ministry officials said, declining to identify the cable producers.
The reactors, which each have a capacity of 1,000 megawatts (MW), would remain closed for about four months, the government said.
Of the three reactors, two are in Kori, about 320 km southeast of the capital Seoul, and one is in Wolsong, about 280 km from Seoul, the Nuclear Safety and Security Commission said.
A fourth newly built nuclear power reactor, also in Wolsong, which is waiting for operational approval, would also have its cable replaced, the statement added.
The emergence of a new scandal will be damaging for authorities and South Korean President Park Geun-hye pledged at a cabinet meeting a thorough investigation.
The energy ministry said it would ask the international nuclear safety evaluation body Tuv Sud to include the latest case in a review of safety at all reactors, which started this week.
UNPRECEDENTED POWER SHORTAGE
The nuclear problems could increase the risk of power shortages in the hot Korean summer when power demand is seasonally high for air conditioning.
The energy ministry warned the worst shortages could occur in August, and it would consider various measures including rolling blackouts and spreading out holidays to curb demand.
"We expect unprecedented supply shortage this summer as we have to meet power demand while three reactors are halted," said Han Jin-hyun, Vice Minister for Trade, Industry and Energy.
He added power saving measures would be unveiled this Friday.
The energy ministry sees power supply this summer at about 77,000 MW, less than 80,000 MW projected before the closure and short of demand projection of 79,000 MW.
Last year, South Korea was forced to take power saving measures to avoid blackouts after it closed two reactors to replace parts supplied with fake certificates and extended the shutdown of another reactor where microscopic cracks were found.
($1 = 1122.3250 Korean won)
(Additional reporting by Se Young Lee; Editing by Ed Davies)