Luxembourg Demands a Seat as Cattenom Reactor Turns 40

The four reactors at France's Cattenom nuclear plant turn 40 in 2026 — the exact lifespan their builders once had in mind. Ten kilometres downstream, on the same river, Luxembourg is again insisting that age should mean retirement, not renewal. As the formal review that could extend the life of the first reactor gets under way, the Grand Duchy is pressing a familiar but unresolved question: who gets a say over an ageing reactor that sits just across a border?

Cattenom's four 1,300 MWe pressurised water reactors, operated by the state-owned utility EDF, were designed when 40 years was the working assumption for key equipment. Reactor 1 was connected to the grid on 13 November 1986 and entered commercial service on 1 April 1987. The plant lies roughly 10 km from both the German and Luxembourg borders, on the Moselle, in France's Grand Est region — close enough that any incident would be a regional event, not merely a French one.

A regulator opens the door to another decade

On 1 July 2025, France's nuclear safety regulator — the Autorité de sûreté nucléaire et de radioprotection (ASNR), formed in 2025 from the merger of the former ASN and IRSN — issued a generic-phase decision, n° 2025-DC-016. It concluded that the country's twenty 1,300 MWe reactors, including all four at Cattenom, may continue operating for the ten years following their fourth periodic safety review, provided EDF carries out a programme of upgrades.

"All the provisions provided for by EDF and those it prescribes open up the prospect of continued operation of these reactors for the ten years following their fourth periodic review," the ASNR said.

That decision is generic: it sets the framework for the fleet but does not, by itself, authorise any single reactor to keep running. Each unit must still pass its own reactor-by-reactor review, and the review report for each reactor is subject to a public inquiry — an enquête publique — before continued operation is authorised. The path to it was lined with public consultation: a national process on the provisions for operating beyond 40 years ran from 18 January to 30 September 2024, followed by a consultation on the draft decision itself between 16 May and 15 June 2025.

The financial and industrial scale is substantial. EDF expects to spend about EUR 6 billion (USD 7 billion) on the life-extension programme for the 1,300 MWe fleet, with modifications applied unit by unit and the fourth periodic reviews stretching out to 2040.

Cattenom 1 first in line

Cattenom reactor 1's fourth periodic review — its visite décennale — is scheduled for 2026–2027, placing it among the first 1,300 MWe units to face the process. Outage preparation began in early 2026, and the ASNR's review calendar lists the periodic review for October 2027. The timing turns the reactor's 40th birthday into a legal and symbolic flashpoint: the precise design-life threshold the machine was built to reach is also the moment a regulator may permit it to run on.

For the Greater Region — Luxembourg, Saarland and Rhineland-Palatinate — that coincidence is charged. It is one of the most concrete cross-border tests of nuclear governance in Europe: a sovereign state sitting kilometres downstream, with no veto, repeatedly demanding to be consulted over a plant another country has decided to keep running for another decade.

Luxembourg's long campaign for a voice

Luxembourg's position is not new, but it has hardened around each milestone. At the Franco-Luxembourg Joint Commission for Nuclear Safety on 2 February 2021, the Luxembourg delegation underlined its wish to take part throughout the next review.

"Luxembourg emphasised its willingness to be associated and consulted at all stages of the next Cattenom review," the delegation said, while expressing concern about operation beyond 40 years.

In April 2021, Luxembourg, Rhineland-Palatinate and Saarland jointly pledged to act against the planned extension beyond 40 years and to push for full transparency and participation. Then, in a communiqué dated 11 September 2024, the Luxembourg government adopted a formally critical position on extending the lifespan of certain 1,300 MW reactors, Cattenom among them, reiterating that at-risk plants including Cattenom should be closed.

The government's underlying objection is technical as much as political. As a spokesperson for Luxembourg's Ministry of the Environment, Climate and Biodiversity put it: "These nuclear power plants planned in the 1980s were not designed to operate for more than 40 years."

Civil society raises the stakes

Outside government, Greenpeace Luxembourg has run a petition — "40 years is enough" — opposing any extension of reactor 1. Roger Spautz, a nuclear campaigner and founding member of the group, framed the issue in stark terms of risk.

"In view of the defects, uncertainties and risks, the extension of Cattenom 1's lifespan must be prevented. An operating authorisation beyond the expiry of the 40-year lifespan represents a risk to the safety of everyone," Spautz said.

The dispute crystallises a broader European tension. France is in the middle of a nuclear revival built partly on extending the life of its existing fleet, treating decades of additional output as cheap, low-carbon and strategically valuable. Its anti-nuclear neighbours invoke cross-border environmental-impact rights and the principle that a state downstream of a 40-year-old reactor deserves more than to be informed after the fact.

The mechanics now favour Paris. The generic green light is granted, the reactor-by-reactor reviews are scheduled, and the upgrade money is committed. Luxembourg's leverage rests not on a veto it does not hold but on consultation, transparency and the political weight of three neighbouring governments. The coming public inquiry on Cattenom 1 will be the first real measure of whether that is enough to shape the future of a plant whose 40th year has arrived.