ASN extends water-discharge rule changes as heatwave continues

08 August 2022

The French nuclear regulator Autorité de Sûreté Nucléaire (ASN) has extended temporary modifications to the strict rules regulating the maximum temperature of cooling water released from five nuclear power plants as the country experiences an ongoing heatwave.

The Blayais plant on the banks of the Gironde estuary near Blaye, France (Image: Marc-Didier / EDF)

In recent weeks, high river temperatures have threatened to reduce France's already low nuclear output at a time when almost half its reactors are offline due to corrosion issues and maintenance.

In mid-July, ASN introduced temporary modifications to the cooling water rules at the Blayais, Bugey, Golfech, Saint Alban and Tricastin nuclear power plants until 24 July. However, on 21 July it adopted a decision to extend this period until 7 August.

ASN has now adopted a decision setting temporary requirements relating to thermal discharges from the five plants until 11 September.

It noted grid operator RTE had identified the need to maintain the plants at a minimum level of electricity production until 21 August to ensure the security of the electricity network. In addition, the context of pressure on the reserves of natural gas and of water for hydroelectric dams for the autumn and winter of 2022/2023 led the government to save them now by optimising the electricity production of nuclear origin.

"The Ministry of Energy Transition considers that it is a public necessity to favour the production of electricity of nuclear origin and therefore to maintain the production of these five power stations until 11 September despite the exceptional climatic conditions," ASN said. "In this context, EDF has submitted to ASN a request for temporary modification of the thermal discharge limits of the Blayais, Bugey, Golfech, Saint-Alban and Tricastin nuclear power plants until 11 September 2022."

ASN said it adopted a decision on 4 August to temporarily modify the limits of thermal discharges from these power plants, "accompanied by reinforced monitoring of the aquatic environment, in particular of fish life". This decision, it added, was approved by the minister responsible for nuclear safety on 5 August.

Researched and written by World Nuclear News