Belgium will shut down its first nuclear power plant on Friday as part of its nuclear phase-out plan, but the decision has raised doubts and controversy amid soaring energy prices and the war in Ukraine.

The operator Engie will shut down one of the four reactors at the Doel nuclear power plant in the northern port of Antwerp on the river Scheldt at around 9pm. This plant alone was able to generate up to 10% of the country's electricity.

The decommissioning of the 40-year-old Doel 3 reactor has been prepared for a long time. It is part of the Belgian nuclear phase-out plan approved in 2003, which originally envisaged the shutdown by 2025 of the seven reactors that provide about half of the country's needs.

However, as the deadline approaches, the federal government seems to be in doubt and is divided on the issue, while rising energy costs are putting a strain on households and businesses.

In March, it had already reached a difficult agreement to extend two of the seven nuclear reactors until 2036. For the future, Belgium is not closing the door on "new generation" nuclear power.

However, Minister of the Interior Annelies Verlinden from the Christian Democratic and Flemish party (CD&V) stirred up a hornet's nest last week by asking the Belgian nuclear safety authority (AFCN) whether it would be possible to postpone the decommissioning of Doel 3 in the event that a relaunch of the reactor was envisaged at a later date.

Similarities to nuclear debate in Germany

Deputy Prime Minister Petra De Sutter from the Green Party (Groen) said she was "shocked" by this questioning of the timetable "just a few days before the shutdown of operations".

Engie also responded in unequivocal terms. "The reactor will be shut down permanently and is not intended to restart," a spokeswoman for the operator told AFP, stressing that she had not received any request from the government in this regard.

For its part, the AFCN did not officially close any doors but replied to Verlinden that a "very late" decision to extend the reactor was "not a sign of good governance" and that it could "not guarantee that a late and unprepared scenario does not entail a risk for nuclear safety".

Pro-nuclear activists were due to demonstrate in Doel in the morning to demand that the reactor be kept "in an operational state".

In theory, a restart of the reactor would not be impossible. After the shutdown on Friday evening, preparatory work will take about five years before the reactor is dismantled.

"No technically irreversible operations are taking place during this first phase," acknowledged plant manager Peter Moens.

But he said a postponement or reversal of the process would be "neither wise nor advisable" for technical and operational reasons, citing the lack of fuel and personnel.

The Belgian debate echoes that of Germany, where conservative and liberal politicians are calling for the extension of the country's last three nuclear reactors beyond the end of 2022, when they are due to be shut down.

For now, Berlin has merely agreed to keep two reactors on standby until spring 2023 to deal with any emergencies.

In Belgium, transmission system operator Elia said it did not expect any supply risks from the "planned shutdown".

"We have enough generating capacity available to meet demand," a spokesman said.

The boom in renewable energy, solar and wind, including offshore, has helped the country achieve record exports in 2021. Gas-fired power stations accounted for a quarter of the energy mix.

Greenpeace says that "the closure of Doel 3 does not pose any problem for the security of supply and has no significant impact on the price of electricity".

However, the French-speaking liberals of the Mouvement Réformateur (MR) fear shortages.

"With the risk of blackouts in France this winter, with Germany leaving nuclear power but running out of gas, we know that we will have major difficulties," warned former MR energy minister Marie-Christine Marghem.

She called for the repeal of the nuclear phase-out law, which she considers a "has-been".