ASNR
Autorite de surete nucleaire et de radioprotection, France's nuclear safety and radiation-protection regulator.
Last refreshed: 20 July 2026 · Appears in 1 active topic
Why did France's nuclear regulator let two Bugey reactors run hotter than the Rhone's normal limits allow?
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France cheaper on a waiver ending today
European Energy MarketsBackground
France's nuclear regulator, ASNR, granted Bugey reactors 4 and 5 a temporary thermal-discharge derogation on 10 July 2026, allowing them to heat the Rhone by up to 1C above normal limits so the pair could keep generating through the summer heatwave. The economy ministry ratified the order in the Journal officiel on 11 July, and it runs to 20 July inclusive, with reinforced environmental monitoring attached.
ASNR came into being on 1 January 2025, formed by the merger of the safety authority ASN and the radiation-protection research body IRSN under a law passed 21 May 2024. It now holds both regulatory and research functions that were previously split, giving it sole authority over thermal-discharge limits, cooling-water rules and operating licences across France's nuclear fleet.
The Bugey waiver sits inside a wider heatwave-driven curtailment: Golfech 2, Bugey 3 and Chooz 2 shut fully around 12 July on the same river-cooling limits, with several more units running at reduced power. ASNR's derogations are the mechanism by which France trades environmental headroom for grid output when a heatwave and high demand coincide, a balance that will recur every summer as the Rhone and other rivers run warmer.