SEOUL South Korea's Kori No. 4 nuclear reactor was manually shut down after the water level in a collection tank rose due to a coolant leak, a spokesman at the reactor's operator said on Tuesday.
"We estimate the water level of the reactor's collection tank increased after coolant was leaked," said Lim Dae-hyun, the spokesman at Korea Hydro & Nuclear Power Co Ltd (KHNP) [KRHYDR.UL].
Lim added that there was no release of radioactivity and that the cause of the water level increase was being investigated.
The 950-megawatt Kori No. 4 reactor is near Busan, a city more than 300 km (190 miles) southeast of the capital, Seoul.
KHNP, fully owned by state-run utility Korea Electric Power Corp (KEPCO), runs the country's 25 nuclear reactors, which supply about a third of South Korea's electricity.
(Reporting by Jane Chung; Editing by Jonathan Oatis)