French nuclear power plant shuts down reactor due to heat wave

Background: The 28-degree rule

The background is a regulation from 2006 that stipulates that the water temperature of the Garonne must not exceed 28 degrees after the plant's discharges. If the river temperature already rises to comparable values as a result of weather conditions, further heating by the plant becomes legally problematic.

The heat wave affects large parts of France. On Wednesday, the number of départements for which the second-highest heat warning level Orange was in effect rose from 61 to 67. Authorities urged the population to drink sufficient fluids, avoid physical exertion, and pay particular attention to protecting elderly and health-vulnerable people.

Expansion of heat warnings

In many places, temperatures were well above 30 degrees, and in the southeast of the country values climbed to around 40 degrees. Weather services expect the heat stress to persist in the coming days.

EDF stated that the operational safety of the facility is not compromised. The company also pointed out that the shutdown is part of the usual management during the summer months when river water temperatures reach permitted limits. France obtains the largest share of its electricity from nuclear energy.

Reactions from environmental groups and authorities

Environmental organizations see the incident as evidence that existing regulations to protect river ecosystems are taking effect. They also called for a greater expansion of renewable energies to reduce dependence on river water for cooling.

The responsible supervisory authorities announced that they would continue to monitor the situation. Should the temperatures of the Garonne remain permanently above the limit values, further technical adjustments or short-term shutdowns are possible.

The incident in Golfech is part of a series of similar measures taken by European power plants during past hot summers. In several countries, reactors have had to reduce output or temporarily go offline in recent years because cooling water temperatures reached limit values.

EDF announced that a decision on restarting the reactor would be made over the course of the weekend, as soon as the temperature development of the Garonne allows for a reliable assessment.