Suspect replacement parts at South Korea's nuclear plants have prompted the government to order the immediate shutdown of two power-generating reactors.
Reactors five and six at the Yeonggwang nuclear complex were ordered to go offline Monday.
Government officials say, before they can re-start the reactors, technicians will need to replace thousands of fuses, cooling fans and other parts.
Minister of Knowledge Economy Hong Suk-woo says the components that were installed came with forged quality certificates.
The minister says these are non-core components and such parts do not pose a safety threat. He adds there is no connection between the possibly counterfeit parts and a series of malfunctions at South Korea's nuclear reactors this year.
The two reactors could be out of service for months.
Hong warns of ramifications from such a prolonged shutdown.
The government minister says it is inevitable this will cause an unprecedented power shortage during the coming winter months.
South Korea's 23 nuclear power reactors supply more than one-third of electricity in the country, the world's 15th largest economy.
As is the case with neighbor Japan, South Korea has scant natural energy resources. Following the catastrophic meltdowns of several reactors in Fukushima (Japan) in March of 2011, a rising number of people in South Korea - as has been the case in Japan - are questioning whether the risks outweigh the benefits of nuclear power.