Neither reactor is in danger of releasing radiation, officials at Korea Hydro & Nuclear Power, Yonhap News Agency reported. The first reactor, the Shingori 1 in Busan, South Korea, 280 miles south of Seoul, was shut down after it detected a problem with the control rod that governs the rate of fission inside the reactor.
The second reactor was shut down about two hours later at Younggwang Nuclear Power Plant in South Jeolla Province, about 220 miles south of Seoul. The No. 5 reactor there was halted due to low water levels.
The news comes as public fears over nuclear accidents remain high in the wake of the Fukushima disaster in Japan in March 2011, when an earthquake and tsunami decimated the nuclear power plant, causing large amounts of radiation to leak, Yonhap reported.
South Korea has 23 nuclear reactors online, producing about 30 percent of the nation's electricity, Yonhap reported.