By Meeyoung Cho
SEOUL (Reuters) - The hacking of South Korea's nuclear operator means the country's second-oldest reactor may be shut permanently due to safety concerns, said several nuclear watchdog commissioners, raising the risk that other aging reactors may also be closed.
"The operator failed to prevent it (the hack) and they don't know how much data has been leaked. If the old reactor is still allowed to continue to run, it will just hike risks," said Kim Hye-jung, one of the nine commissioners who will this month review an application to restart the Wolsong No.1 reactor.
The future of Wolsong No.1, shut in 2012 after reaching its 30-year lifespan, is seen as critical to the fate of other reactors, including the oldest Kori No.1 which had its lifespan extended by 10 years to 2017. Nuclear power accounts for about a third of South Korea's electricity supply.
More nuclear closures would boost fuel imports, which had soared since late 2012 after some reactor closures forced Asia's fourth-largest economy to replace nuclear power with liquefied natural gas and thermal coal.
It could also mean increased greenhouse gas emissions, making it harder for Seoul to achieve its target of cutting emissions by 30 percent of business as usual by 2020.
Korea Hydro and Nuclear Power Co Ltd, which operates the small 679-megawatt Wolsong No.1, has said its headquarters computer system was hacked last month, but that all reactors remain safe.
The operator, part of state-run utility Korea Electric Power Corp, has been seeking to restart Wolsong No.1 and runs 23 reactors, producing a third of South Korea's power.
The Nuclear Safety and Security Commission will start on January 15 at the earliest to review whether to approve to extend Wolsong's lifespan by 10 years to 2022.
Five of nine commissioners contacted by Reuters said they held doubts over the viability of Wolsong No.1. "The reactor has completed its designed lifespan. Even if modified, still it is not safe," said commissioner Kim Ik-jung.
If five vote against a restart, the reactor will be shut permanently. The other commissioners were not reachable or declined to comment.
Korea Hydro and Nuclear Power argues that its reactors are safe as they are inaccessible from external networks, like the company's hacked computers or the Internet.
A spokesman at Korea Hydro and Nuclear Power said the company would accept whatever the nuclear watchdog decides.
Even those commissioners who deem the reactor safe think that other issues such as public pressure will likely influence their decision, which is expected in February at the earliest.
Concerns over nuclear power have grown since the Fukushima disaster in Japan in 2011 and revelations in 2012 of fake certificates for reactor parts in South Korea.
(Additional reporting by Sohee Kim and Brian Kim; Editing by Henning Gloystein and Michael Perry)