Tihange`s reactor 1 was taken offline at 10:35 p.m. (2135 UTC) Friday following a fire in a non-nuclear section of the plant, operator Electrabel told Belgium`s private Belga news agency.
Electrabel said the incident did not impact workers, the public or the environment.
The power plant - about 70 kilometers (43 miles) from the German border city of Aachen - is controversial in neighboring Germany.
Earlier this week regional government authorities in Germany protested Belgium`s decision to restart the plant`s reactor 2 following a two-year shutdown after discovery of micro-cracks in the reactor`s cement casing in 2012.
German neighbors unhappy with nearby reactors
North Rhine-Westphalia`s state government has protested restarting the 40-year-old reactors, claiming it is a safety hazard and located to millions of people as four of Germany`s 10 largest cities - Cologne, Düsseldorf, Dortmund and Essen - are located within the Rhineland state.
Seven nuclear power plants produce about half of Belgium`s electricity supply. Two other 40-year-old reactors meant to be decommissioned this year - Doel 1 and 2 - are being kept online for another decade to help meet domestic demand.
Belgium said it`s committed to phase out nuclear power entirely by 2025. Germany is also phasing out its nuclear plants, with the remaining slated to close by 2022.
Fire shuts down Belgium`s Tihange nuclear reactor
19 December 2015
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A nuclear reactor at the Tihange power station in Belgium has been shut down following a fire inside the plant. Germany has protested the power station near the border.
