French electricity giant EDF closed down nuclear reactors at two plants in the south of France this week due to the heatwave. Supporters of nuclear power vaunt its role in de-carbonising energy production but can it still be an energy of the future if the future is likely to be hotter?

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This week’s scorching temperatures, over 40°C in many parts of the country, led EDF to close down production at the Golfech (Tarn-et-Garonne) and Tricastin (Drôme) nuclear power plants.

Nuclear reactors need large amounts of water to cool them down and around two thirds of France’s 58 reactors get their water supplies from nearby rivers. Once the cooling done, the warmed water is discharged back into the river. But recent droughts have lowered water levels in the Garonne and Rhône and the heatwave has increased the temperature of the water.

EDF followed French regulations which stipulate that in order to protect plant and animal life, power generation must be cut when water temperatures go above 28°C or when river levels and flow rate are low. But the electricity giant insisted there would be no impact on power supply.

“Electricity supplies are absolutely not threatened by the intermittent stoppages or power reductions,” Etienne Dutheil, head of nuclear production at EDF, told French daily Libération. “By way of comparison, in winter, we require up to 100 GW, this summer we’ve never gone beyond 60 GW despite the growing use of air-conditioning”.

He added that near to 20 out of France’s 58 reactors have been stopped for maintenance or refueling “without it affecting the network’s equilibrium”.

No need to panic

As the situation stands “there’s no need to panic because there’s no threat to electricity supply in the short term,” says nuclear specialist Yves Marignac, spokesperson with Négawatt, a non-profit working on energy efficiency.

But the risk of power cuts would increase if temperatures reach what is known as “grand chaud" (high heat) in the French nuclear power industry when the reactor is no longer considered safe enough to run.

“Electricity generation through reactors is threatened by heatwaves, especially those on rivers as is the case in France where two thirds are on rivers," Marignac explains. "If heatwaves are more intense and frequent, in the range of 45°C and lasting for some days, there’s also risk of failure of equipment due to "grand chaud".

“We’re not up to that yet, but as climate science tells us there’s going to be more heatwaves and they could be longer and they could be warmer that means we could get to that point in coming years and decades."

'Vulnerable to climate change'

France's 58 reactors currently account for over 75 % of its electricity needs. While it is set to close 14 reactors by 2035 as part of its 10 year energy plan, nuclear remains an important part of the energy mix. Proponents of nuclear power say it makes environmental sense since it produces no carbon dioxide (CO2).

But anti-nuclear groups like Sortir du Nucléaire (exit nuclear) have seized on the latest heatwave to show “nuclear is vulnerable to climate change”. What's more they claim "it won't save the climate" because it does, for example, produce greenhouse gases through its waste management, building of nuclear plants and processes for mining and refining uranium ore.

“Continuing this dangerous adventure is no longer an option,” states the non-profit.

Etienne Dutheil of EDF maintains depleting water supplies and higher temperatures need not hamper the future of nuclear plants citing Palo Verde in the Arizona desert.

"Its cooling is based on collected waste water from neighbouring towns," Marignac comments, "so there's no need for an adjacent river."

Nonetheless, the future will have to include more diversified sources of electricity.

“What we need to acknowledge today is that whether with nuclear power or renewables, the electric system is going to depend increasingly on weather conditions and be increasingly threatened by climate change," Marignac says. "So we need to go for a more diverse electricity production but furthermore we need to act on our electricity consumption.”

That means better controlling our electricity needs, thinking about how we use it, turning off appliances, working on buildings to reduce the need for heating in winter and cooling in summer.

“We really need to think of the need to generate not only low carbon electricity but also to make our overall electricity system more robust to the kind of events we see today which unfortunately is probably just the beginning of extreme climate events.”

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