Belgian nuclear regulator tells govt not to extend oldest reactors

BRUSSELS, March 6 (Reuters) - Belgium's nuclear regulator has advised the government against a life extension of the country's three oldest reactors, despite the risk of a gap in electricity supply over the next two winters.

Instead, it proposed adjusting the life extension plans of two newer reactors so that safety upgrades are staggered, keeping the power on during the coming crunch period.

The proposal was in a written opinion submitted to the government by the regulator and seen by Reuters on Monday. The document has not been made public yet but the regulator, FANC, confirmed its authenticity to Reuters.

Belgium had planned to exit nuclear energy in 2025, but Russia's invasion of Ukraine has forced the government to rethink plans to rely more on natural gas.

Earlier this year the country reached a tentative agreement with nuclear operator Electrabel, a subsidiary of French energy company Engie (ENGIE.PA), opens new tab, to extend the lives of two newer reactors for 10 years.

But that plan would first require powering down the reactors for safety uprades, which would leave Belgium with a 1.5 gigawatt power gap for the next two winters that cannot be replaced with other types of energy generation, electricity system operator Elia (ELI.BR), opens new tab has warned.

The government's proposed solution - temporarily extending the lives of Belgium's three oldest reactors - was too complex, would pose safety concerns, require additional nuclear fuel and mandate amendments to Belgium's nuclear regulatory framework, the regulator said.

It would also run contrary to Engie's wishes, FANC added.

Instead, the regulator recommended extending the life of the two newer reactors, Doel 4 and Tihange 3, without stopping them for a full safety upgrade.

Under the new plan, the reactors would be partially upgraded each summer beginning in 2025 to meet more stringent requirements over time, and remain available over the next two winters, after which other types of power plants are scheduled to come online.

The Belgian government discussed the opinion at a Monday cabinet meeting and agreed to ask Electrabel to submit safety documents to the regulator to assess the new plan for the younger reactors, a spokesperson for the energy ministry said.

The spokesperson declined to specify whether the government was abandoning the idea of extending the lives of the three oldest reactors but said the government had "taken note" of the opinion and would take it into account.

Engie declined to comment on Monday beyond CEO Catherine MacGregor's remarks while delivering annual results last month.

Reactors "Doel 1 and 2 and Tihange 1 are not in the scope of an extension (discussion) at this stage, and we don't plan for them to be," MacGregor said on Feb. 21.

"They're almost 50 years old, they're at the end of their life ... there is no nuclear safety framework as such that would exist to provide for such a short-term extension."