A nuclear reactor in southeastern South Korea went offline on Tuesday because of a glitch in a power transmission line, which came in contact with a sheet of vinyl used for greenhouses, a state-run power company said.

   Electricity in the line, one of three high-voltage power lines connected to the reactor, was cut off suddenly when a 5-meter-wide vinyl sheet carried by wind touched the line, according to Korea Electric Power Corp. (KEPCO). Power was soon returned to the line, and a worker from the company removed the sheet, the company said.

   The Gori-2 reactor northeast of Busan, the country's largest seaport, was shut down at 10:30 a.m., according to the state-run nuclear power company, Korea Hydro & Nuclear Power Co. (KHNP).

   "Electricity in one of the three high-voltage power lines was cut off suddenly, triggering an overload in the remaining two lines," KHNP said. "The reactor's emergency power relay system kicked in, causing the reactor to stop electricity generation."

   The power line is used to send electricity from the nuclear reactor to the nearby industrial city of Ulsan.

   "Because it was a precautionary shutdown, the reactor was in stable condition and there was no release of radioactive materials into the environment," KHNP said.

   The company said the Gori-2 will go back online once all inspections are completed. It, however, declined to say when normal operations will recommence.

   The 650-megawatt light-water reactor started commercial operations in July 1983 and is the third-oldest nuclear unit in the country after the Gori-1 and Wolsong 1 reactors.

   The Gori-1 reactor experienced a shutdown in mid-April that caused the government to keep the unit offline for about a month to give inspectors plenty of time to check for possible safety problems. 

   South Korea has moved to strengthen monitoring and enhance safety requirements for all of its 21 commercial reactors, following a rise in public concern after Japan's Fukushima nuclear disaster. (Yonhap News)