NSSC said in a statement that the shut down was triggered by two damaged control cards that operate control rods.
The reactor will immediately start operation as the damaged cards have been replaced, the statement added.
Meanwhile, undisclosed officials from Korea Hydro & Nuclear Power (KHNP) were quoted by Yonhap News Agency as saying that the reactor will require at least two days to reach its maximum output.
Located in the Gyeongsangbuk-do province of South Korea, the Hanul nuclear power plant has six pressurized water reactors (PWRs) with a total installed capacity of 5,881MW.
South Korea currently operates a total of 23 nuclear reactors, which supply about 30% of its total electricity consumption, according to the news agency.
