The trouble with the French nuclear stations and the hot weather

In mid-May 2022, thirty of the 56 French nuclear power plants were at a standstill for safety research, fuel exchange and overhaul. Also in May, a number of nuclear power plants had to run at less power because the cooling water was already too hot at that time. Now that it is extremely hot again – the new ‘normal’- the French electricity company EDF has announced that nuclear power plants on the Rhône should reduce their capacity. This also applies to two reactors in Doel in Belgium since yesterday afternoon. Water is an increasing problem for nuclear power plants, not only the temperature of the cooling water, but also the huge quantities that nuclear power plants use. And that in times of ever faster warming and increasing (fresh) water scarcity.

In order to prevent the nuclear power plants on the Rhône River from having to close completely, the nuclear regulator Autorité de Sûreté Nucléaire (ASN) decided on July 13 to loosen the rules for the maximum temperature of the cooling water. A ” minimum power is essential for the safety of the power grid”. The Ministry of Energy Transition therefore considers this a”nécessité publique”. This release of the maximum temperature is a further attack on water quality, all the more so because the maximum water temperature in France is already higher than in Switzerland and Germany, for example.

In 2015 and 2018, France also suffered from power outages due to heatwaves. In 2012 and 2017, a total power outage (blackout) threatened due to a very cold winter period. Foreign countries had to step in. The idea that French nuclear power plants can always provide enough electricity turns out to be an illusion. The large-scale dependence on nuclear energy, together with climate change, causes an increasing vulnerability of the energy supply. This is the first time this has happened so early in the summer. Since yesterday afternoon, the Belgian nuclear reactors Doel 1 and 2 are only allowed to produce half of the Power: “Environment restriction: modulation to respect the environmental temperature limits of the cooling water”. That measure appears to be lifted again this morning. For me, this is an extraordinary situation.

As we wrote earlier, many French nuclear power plants have been at a standstill for months due to technical problems. All this forces France to import electricity on a large scale.

French nuclear power plants vulnerable in summer

In addition, in May, several nuclear power plants already had to deal with restrictions on production. Due to the first heat wave of this year, the temperature in a number of Rivers had already increased to such an extent that the cooling water would become warmer than the permit permits when produced at full power. EDF, a week ago 100% nationalized, because bankrupt, then mainly switched off the four units of the Blayais nuclear power plant on the Gironde, about 60 kilometers from Bordeaux, and of Saint-Alban on the Rhone. At the beginning of July, it turned out that a total of six nuclear power plants are again under stricter supervision due to cooling water problems. EDF announced on July 15 that the Tricastin, Saint Alban and Bugey nuclear power plants, all located on the Rhone, will be allowed to supply less power due to the second heat wave of this year.

During a heat wave in the summer of 2015, the rivers warmed up and the French nuclear power plants were allowed to supply less electricity to prevent the discharged cooling water from becoming too hot. The government allowed this cooling water to be 28 degrees Celsius. That is higher than the 25 degrees that are considered acceptable in Switzerland and Germany. At the beginning of August 2018, there was also a heat wave that affected nuclear power plants in a number of European countries.

Most French nuclear power plants draw the required cooling water from rivers, such as the Rhône which rises in the Swiss Alps at the Rhône Glacier. Research reports have recently appeared on the effects of climate change on the Rhine, which also begins in Switzerland. Melting snow has a large share in the amount of water that enters Swiss rivers annually, according to reports by the International Commission for the hydrology of the Rhine areas (KHR). Melting snow provides 39% of the water in the Rhine, while glaciers account for 2%, and 59% is rainwater. Among other things, it follows from these studies that winters will become more humid and summers drier. The snow melts earlier in the spring than was the case in the past. As a result, the layer of snow on the glaciers disappears earlier, with the result that the glaciers melt faster. The proportion of river water due to the melted snow and glaciers will therefore decrease as early as spring. In the summer one will have to have rainwater, but because the summers get drier the water level will be lower in the summer. The result is less available cooling water for power plants. And that is while the demand for electricity is increasing in ever warmer summers due to the increase in the number of air conditioners.

In this way, the French electricity supply is also becoming increasingly vulnerable, especially because several nuclear power plants are often located together and therefore extra cooling water is required. In the long run, an electricity supply that does not require large-scale cooling will become increasingly important.

Nuclear energy and water use

Nuclear power plants require huge amounts of water. We have written about it more often since (2014)and a shortage of (fresh)water is regularly warned. For example, in 2016, it was estimated that 4 billion people are seriously deficient in water for at least one month a year. A few years ago, the United Nations warned of a global shortage if we no longer take into account how and for what we use water.

The authors of the UNESCO World Water Report in 2015 (‘Water for a sustainable world’) are therefore clear: because coal – gas and nuclear power plants use a lot of water, the support for sun and wind must increase drastically: “In terms of water impacts, wind and solar PV are clearly the most sustainable forms of power generation.”