Chooz

EDF confirmed on 12 July 2026 that Chooz was taken fully offline on cooling-water discharge limits, alongside Golfech and Bugey 3, as a second heat dome pushed Meuse river temperatures past the environmental ceiling; the plant had been added to EDF's heat-curtailment warning list only two days earlier, alongside standing alerts for Blayais, Bugey, Golfech and Saint-Alban. Chooz-2 is reportedly scheduled to return to service around 25 July 2026, pending river temperatures easing.

Chooz sits in the Ardennes on the Belgian border. Its two operating units, Chooz B1 and B2, are 1,500 MW pressurised water reactors of the N4 design, the precursor to the EPR, commissioned in 1996 and 1997. They replaced Chooz A, France's first PWR at 305 MW, run by EDF with Belgian utility SENA from 1967 until its 1991 shutdown; decommissioning of Chooz A's reactor vessel began in 2016.

Chooz's July 2026 outage is its first confirmed river-cooling curtailment in this warning cycle, arriving in the same heat dome that also took Golfech and Bugey 3 fully offline. It joins Blayais, Bugey, Golfech and Saint-Alban on EDF's list of river-cooled sites exposed to warming summers, a reminder that French nuclear baseload, long treated as weather-proof, is becoming a variable that tightens repeatedly, not just once, as demand peaks.