# EDF shuts Nogent and Bugey reactors as heatwave pushes cooling rivers above legal limits
> 4 GW goes offline, 6% of French nuclear capacity, as Seine and Rhone temperatures breach discharge thresholds; RTE grid stress warning already in force

**Meta:** type: story · date: 2026-06-25 · heads: What Broke, Whose Money · 5 takes · 2 lenses · 5 regions

## Summary

EDF shut two nuclear generating units on June 25 as the Omega heatwave drove cooling-river temperatures above legally permitted discharge limits. Nogent-sur-Seine, on the Seine about 110 km south of Paris, and Bugey, on the Rhone near Lyon, were taken offline, removing 4 GW of baseload, roughly 6% of France's installed nuclear capacity. Grid operator RTE had already issued a supply-stress warning covering the June 25 peak demand window. France sends around 15% of its electricity production to neighbouring grids, particularly Belgium, Italy and Germany.

## Why it matters

France is the largest nuclear exporter in Europe and the marginal baseload supplier to Belgium, Italy and Germany during heat events. Losing 6% of nuclear capacity at peak demand forces RTE to absorb the gap with gas-fired peakers and curtail cross-border exports, directly pushing up [TTF spot prices](/en/n/ttf-summer-storage-shortfall) and tightening the margin between supply and demand for the continental [EU Grid](/en/entity/eu-grid).

## What to watch

- Whether Bugey and Nogent return to service before the forecast heat-dome break this weekend, when demand eases but river temperatures lag.
- TTF day-ahead and intraday price moves Thursday evening and Friday.
- Whether a second-tier EDF plant along the Loire or Rhone breaches discharge thresholds as the heat lingers.

## Regional takes (batched by bias / lens)

### Pan-European broadcast, English-language; leads with grid-stability angle and cooling-water regulation
- **Euronews** (Europe (pan-European), en) — Euronews reported EDF shut Nogent-sur-Seine (Seine basin, near Paris) and Bugey (Rhone, near Lyon) on June 25 when river temperatures exceeded the legal discharge ceiling; total offline capacity is 4 GW, or 6% of France's nuclear fleet. Grid operator RTE had already issued a stress alert before the shutdowns.
  > "France has taken two nuclear power plants offline after the rivers used to cool them exceeded temperature limits set to protect ecosystems."
  Source: https://www.euronews.com/green/2026/06/25/france-takes-nuclear-reactors-offline-amid-record-heatwave

### unlabelled
- **Argus Media** (Global (energy trade press), en) — 
  Source: https://www.argusmedia.com/
- **Montel News** (Europe (Nordic/power markets), en) — 
  Source: https://www.montelnews.com/
- **energynews.pro** (Europe, en) — 
  Source: https://www.energynews.pro/
- **France 24** (France, fr) — 
  Source: https://www.france24.com/

## Across the graph
- Related: [[france-heat-fifty-deaths-jun25]], [[europe-omega-heatwave-june25]], [[ttf-summer-storage-shortfall]]
- Entities: EU Grid, France

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Canonical: https://rbtfl.xyz/en/n/france-nuclear-edf-heatwave-jun25