ASNR
Autorite de surete nucleaire et de radioprotection, France's nuclear safety and radiation-protection regulator.
France's nuclear safety regulator, formed on 1 January 2025 from the merger of ASN and IRSN, granted Bugey reactors 4 and 5 a one-degree Rhone thermal-discharge relaxation on 10 July 2026 at grid operator RTE's request, a waiver that expired on 20 July.
Last refreshed: 23 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?
Timeline for ASNR
France cheaper on a waiver ending today
European Energy MarketsBackground
ASNR (Autorite de surete nucleaire et de radioprotection) is France's nuclear safety and radiation-protection regulator, formed on 1 January 2025 when the safety authority ASN merged with the radiation-protection research body IRSN under a law passed 21 May 2024. The merger gave ASNR sole authority over reactor operating licences, cooling-water rules and thermal-discharge limits that were previously split between the two predecessor bodies.
That authority includes granting temporary derogations letting reactors run outside normal environmental limits during periods of grid stress, such as the one-degree relaxation of the Rhone thermal-discharge limit it granted Bugey reactors 4 and 5 on 10 July 2026 at RTE's request, ratified in the Journal officiel the next day.
Derogations like this are the mechanism by which France trades environmental headroom for electricity output whenever a heatwave and high demand coincide, a trade-off that recurs each summer as French rivers run warmer.