Golfech nuclear reactor shut down again as heatwave pushes Garonne toward 28°C

Sunday 09 August 2026 - 08:45

By: Sahili Aya

Golfech nuclear reactor shut down again as heatwave pushes Garonne toward 28°C

A reactor at France’s Golfech nuclear power plant has been taken offline again as a persistent heatwave drives up the temperature of the Garonne River, forcing the operator to comply with environmental restrictions.

EDF said production unit No. 2 was shut down as a precaution on Saturday evening, just one day after it had returned to service. The decision was prompted by forecasts that the river’s average daily temperature would approach the regulatory threshold of 28°C.

Heat puts pressure on nuclear operations

Located in Tarn-et-Garonne, around 100 kilometres northwest of Toulouse, the Golfech facility relies on water from the Garonne for cooling. The plant’s cooling discharges return water to the river at a somewhat higher temperature, meaning operations are subject to environmental limits designed to protect the river ecosystem.

Under the applicable rules, the plant must reduce reactor output or temporarily suspend operations when the river’s average daily temperature exceeds the established threshold.

EDF said recent weather conditions had caused the Garonne’s temperature to rise significantly and that it was expected to reach 28°C on Sunday, August 9.

The operator therefore opted to stop unit No. 2 in advance rather than wait for the regulatory limit to be exceeded.

Fourth heat-related shutdown this summer

The latest interruption marks the fourth shutdown at Golfech linked to high temperatures since the beginning of the summer.

Unit No. 2 had only resumed operation on Friday after remaining offline since July 29. Although the Garonne cooled below 28°C by July 31, the reactor did not immediately restart because a system required to supply water to the steam generators was unavailable.

Meanwhile, Golfech’s unit No. 1 is already offline for scheduled maintenance and fuel replacement.

The situation leaves the plant with both reactors unavailable, although the duration of the latest shutdown will depend on weather conditions and the river’s temperature.

Climate conditions challenge nuclear production

The repeated interruptions illustrate one of the operational challenges faced by nuclear facilities during periods of extreme heat.

High river temperatures can limit the ability of plants using freshwater cooling systems to operate within environmental requirements. While these restrictions are designed to prevent excessive thermal stress on aquatic ecosystems, they can also affect electricity generation when heatwaves coincide with periods of elevated demand.

For EDF, the immediate priority at Golfech is to maintain compliance with environmental regulations while monitoring the evolution of the Garonne’s temperature.

The plant’s operating conditions will depend largely on whether cooler weather allows the river to return to a level compatible with continued reactor operation.