(Adds background of closures)
BRUSSELS, March 12 (Reuters) - Engie Electrabel, the Belgian subsidiary of French energy group Engie, said on Tuesday its 433 megawatt (MW) Doel 1 nuclear reactor had restarted a few days ahead of schedule after repairs on a water leak in its cooling system.
The reactor has been offline since April 2018 and was due to be restarted on March 15.
An Engie Electrabel spokeswoman said the reactor was currently in a test phase, a normal procedure for a restart, which began late on Monday.
Unprecedented repairs and maintenance work at Belgium’s two nuclear power stations, Doel and Tihange, had threatened power cuts over the winter, but these did not materialise in the end.
Tihange 2, with a capacity of 1,008 MW, is now the only Belgian reactor not operating. It is due to restart on June 1.
Belgium has decided to phase out nuclear power by 2025. However, the lifespan of the Doel 1 and 2 reactors, as well as Tihange 1 - Belgium’s three oldest reactors - will be extended to that date, 10 years beyond the original schedule.
Belgium’s seven reactors - four at Doel and three at Tihange - produce about half of the country’s electricity. (Reporting by Philip Blenkinsop; editing by David Evans)