Korea Hydro and Nuclear Power said all nuclear power plants including Wolsong Nuclear Power Plant maintained normal operations without any shutdown or power reduction.
The nearest nuclear power plant to Pohang is Wolsong, which consists of six reactors located some 45 kilometers away from the seismic center. The KHNP said that while an earthquake alarm went off at one of the reactors, the scale reached far below the standard for a halt in operation.
The Korea Nuclear Radioactive Waste Agency also said it had checked facilities in Gyeongju and found no problems.
Meanwhile, South Korean steelmaker Posco said its Pohang Iron and Steel Plant suffered no damage in its facilities or operations, but added that it was on the watch for any emergent cases.
Hyundai Steel, which manufactures rebar and H-steel at its Pohang plant, said its employees had evacuated upon the earthquake but have returned to work.
Hyundai Motor and SK Innovation, which run plants in Ulsan, also confirmed there were no damages.
Pohang Airport suffered two broken glass windows upon the earthquake, but all airports near Pohang including Uljin and Ulsan airports reported normal operations, according to the Transport Ministry.
Semiconductor manufacturers that work with equipment highly sensitive to vibrations also said that there were no reported damages or major suspension of their production lines.
Samsung Electronics said it immediately surveyed the situation at its plants in Giheung, Hwaseong and Pyeongtaek in Gyeonggi Province, and one in Onyang in Asan, South Chungcheong Province.
SK hynix, which runs plants in Icheon, Gyeonggi Province, and Cheongju, North Jeolla Province, said there were no suspensions.
“Some of the equipment that is sensitive to vibrations is set up so that it automatically halts upon the detection of an earthquake to prevent major damage, and immediately and automatically restarts (when there are no issues),” an official said.
LG Display also said that some precision equipment momentarily halted but returned to normal operation at its plants in Paju, Gyeonggi Province, and Gumi, North Gyeongsang Province.