The heatwave that sweeps across France is likely to lead to production declines, and even to other reactor shutdowns, particularly along the Rhone.
The episode of heat wave that falls on France already has an impact on the electricity production of nuclear power plants. Tuesday, July 23, EDF will shut down at least for a day the two reactors of the Central Golfech (Tarn-et-Garonne). On Saturday, the group had already had to significantly reduce the power of the two reactors of Saint-Alban (Isère) and one of the reactors of the Bugey plant (Ain). France has 58 nuclear reactors in operation.
If the heat wave continues, other reactors, particularly on the banks of the Rhone – which has 14 reactors along the river – could be stopped for one or more days.
EDF is forced by environmental regulations to stop or reduce the production of certain sites to comply with water temperature limits. In the operation of a nuclear power station along the river, water from it is used to cool the steam of the secondary circuit that feeds the turbines, before being discharged into the river.
But this water must not exceed a certain temperature so as not to alter the river's environmental balance. Each plant has specific limitations related to geographical, technical or environmental specificities. "We are watching very closely the temperature of the Rhone, which varies according to what is happening on Lake Geneva"explains to World Etienne Dutheil, director of EDF's nuclear fleet, which does not exclude other stops this week. In 2018, four reactors along the Rhone had to be stopped for a short period.
3% of national production
These rejections are often criticized by environmental groups, who accuse nuclear power plants of helping to warm the rivers. "These thermal discharges act as a barrier that significantly reduces the chances of survival for highly migratory fish, such as salmon and sea trout.", says Network Out of Nuclear.
Biologically, temperatures above 28 oC or 30 oC can interfere with fish reproduction and promote the development of algae and aquatic plants.
These stops have only a minor impact on the production of electricity, while France can produce in summer much more than its consumption and exports to its neighbors. "On Saturday, the decline in reactor production accounted for only 3% of domestic production"explains Etienne Dutheil, who says that over the last ten years, production losses related to heat waves represent 0.3% of production.
Reactors victim of climate
Nuclear power plants do not directly produce CO2 and thus contribute little to global warming. This explains why nuclear power is often presented by the industry as an asset for France in the fight against climate change.
But power stations are themselves victims of the climate: summers will become hotter and more extreme temperatures will multiply. Including in areas that were previously protected from this type of phenomenon: in 2018, for example, Finland had to slow down the production of a reactor that discharged into the sea water to 32 oC.
Other problems may arise: if the pumped water is at a too high temperature, it no longer plays an effective role is cooling role. Similarly, if a river's flow becomes too low, the power plant can not draw enough water, and may dry up the course. A problem which does not concern the Loire or the Rhone, but which can arise, for example, for the power station of Civeaux, at the edge of the Vienne.
Pierre-Franck Chevet, the former president of the Nuclear Safety Authority (ASN), estimated in 2018 that the sites of eight plants – out of the 19 in France – were "More sensitive". The proliferation of severe weather events will make it more difficult in the future to locate power plants on the riverbank. The reactors will then have to favor a location near the sea.
Our selection of articles on the heat wave
- Worldwide, June 2019 was the hottest June in history
- In France, temperatures reached up to 3.5 ° C above normal in the East. The absolute temperature record in France was exceeded in Vérargues in Hérault, with 46 ° C, on June 28th.
- Find our tool to know what are the absolute heat records in your city
- A large part of France has since been affected by drought; in hospitals, schools, parks, businesses, it is time to adapt to high temperatures.
- "Should I insist, worry? Can we sleep a baby without dinner? »: 24 hours in the hot life of a young mother
- Our advice: practical questions (not so) stupid that you ask yourself or the gestures to reduce the temperature at home;
- Interview with climatologist Robert Vautard: "If carbon emissions do not drop, we can expect temperatures of 50 ° C towards the end of the century"