Why did France shut down three nuclear reactors during the heatwave?

France shut down three nuclear reactors at the Golfech, Bugey, and Chooz plants because extreme heat raised river water temperatures, and discharging excessively hot cooling water back into the Garonne, Rhône, and Meuse rivers would violate environmental regulations designed to protect aquatic ecosystems.

What environmental regulation triggered the reactor shutdowns, and how does it relate to river cooling systems?

The shutdowns were triggered by regulations limiting the temperature of cooling water discharged from nuclear power plants into rivers; since reactors use river water for cooling and return it warmer, unusually high ambient river temperatures during the heatwave risked exceeding legal thermal discharge limits—thus requiring temporary shutdowns or power reductions to avoid ecological harm.

France Temporarily Shuts Down Three Nuclear Reactors Over Heatwave

Jul 12, 2026

EDF temporarily shut down three nuclear reactors and reduced power at eight others due to heatwave-induced cooling water restrictions. An exemption was issued for one plant to ensure grid security until July 20.

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