Prime Minister Alexander de Croo has asked Belgian nuclear authorities and the plants' operator, French power giant Engie, to draw up a plan to postpone their shutdown.

"We are considering the possibility of extending the reactors for the 2025-2026 winter," the source said, pointing to the uncertainty over cross-border electricity imports from France's ageing park of nuclear reactors.

Last week, the government decided to extend by 10 years the planned lifespan of two other reactors; Doel 4, near the northern port city of Antwerp, and Tihange 3, near the eastern city of Liege.

The extension was part of an agreement concluded on January 9 between Brussels and Engie, who will be equal partners in a joint venture for the ten extra years.

The latest extension could apply to the Doel 1, Doel 2 and Tihange 1 reactors, which are due to stop production in 2025, the source said, but also to two other reactors.

Maintenance work is planned for Doel 4 and Tihange 3 during the winter of 2025-26, but this could change to keep them in production.

Belgium, which had seven active reactors until last year, took Doel 3 offline in September and Tihange 2 on Tuesday after 40 years of service.

Last year, the country decided to delay its planned 2025 exit from nuclear power by a decade in the face of sky-high energy prices caused by Russia's war on Ukraine.

Belgium's Green Party, part of the ruling coalition, has strongly resisted the move.

Wedged between nuclear-powered France and gas-and-coal-dependent Germany, Belgium's own reactors supply about half of its electricity needs.

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