A general view of the turbine hall of reactor unit number four of the Paks nuclear power plant in Paks © Laszlo Balogh / Reuters
Hungary has shut down a reactor at the Paks nuclear plant due to a malfunction in control equipment, according to national news agency MTI.
Operations were shut down in the first block of the plant.
The malfunction does not pose any safety threats and the security system was not enacted, according to the National Nuclear Energy Office (HAEA).
Once the error is detected and corrected, operations will resume under the official supervision of the HAEA.
Anthony Smith, the nuclear plant's director of communications, said the reactor is expected to reconnect to the network as early as Friday at noon, MTI reported.
The remaining three units at the plant are continuing to operate as usual.
It comes just one week after a separate generator malfunction forced the plant to scale back its output.
The plant suffered a "serious incident" in 2003 due to the inadequate heating of fuel elements, causing a reactor to be out of service for a year.
Located 5km (3.1 miles) from the city of Paks, central Hungary, and 100km (62 miles) from Budapest, the plant is the nation's only operating nuclear power station. Its four reactors produce more than 50 percent of the electrical power generated in the country.
Built in 1982, the plant was developed by Soviet designers.