While the French nuclear fleet is encountering difficulties following the recent discovery of a corrosion defect on several infrastructures and the delay in maintenance due to the coronavirus, it is now the heat that weighs on its operation. Several EDF nuclear reactors have been forced to lower their production due to the high temperatures of the rivers used for their cooling, the company said on Friday.
As a reminder, the power plants pump water to cool the reactors, before rejecting it. However, since 2006, each plant has its own regulatory water discharge temperature limits that must not be exceeded, so as not to heat up the surrounding waterways and to protect their fauna and flora.
” The current exceptional climatic conditions result in a rise in the temperature of the Garonne which has reached 28 degrees »indicates EDF. ” At the request of the national electricity network operator (RTE), production unit no. 2 of the Golfech power plant remains in production (minimum power) », continues the electricity producer. This minimum power corresponds to approximately 300 MW, compared to 1,300 MW normally. The second reactor of the plant located in Tarn-et-Garonne is for its part in scheduled shutdown. ” The exceptional climatic conditions that we have been experiencing for a few days have resulted in a rise in the temperature of the Rhône, which has reached more than 25 degrees. »also notes EDF in a separate point on the Bugey power plant. ” Production units 2 and 5 have been maintained on the network in compliance with the provisions relating to exceptional climatic situations », says the group. These two reactors have ” had to perform load reductions », in other words reduce their power, said an EDF spokeswoman to AFP. The other two reactors of the plant are shut down for scheduled maintenance.
EDF had warned that it could be forced to lower its nuclear production in the coming days and even shut down a reactor at the Tricastin plant (Drôme) due to high river temperatures. It’s not unusual to see production drops for these reasons in the summer period, but this year they came earlier than usual – as early as May. Indeed, such derogations had so far only been used once, in 2018 for the Golfech plant, and this for 36 hours. This year, EDF has already had to reduce the power of a reactor for a few hours in May at Blayais, then in June at Saint-Alban. EDF puts the scope of these events into perspective, however, pointing out that since 2000, production losses have represented an average of 0.3% of the fleet’s annual production. Butaccording to RTE, heat waves have already caused simultaneous unavailability of reactors reaching nearly 6 GW, or about 10% of installed capacity, and this problem is expected to increase in the coming years.
Increased water discharge temperature limits
Other power plants escape a stoppage or a drop in production thanks to environmental derogations allowing them, until September 11, to exceed the temperature limits of the water discharged. A decree published this Saturday in the Official Journal fixes, thus, ” new thermal discharge limits applicable to the reactors of the Bugey, Blayais, Saint-Alban-Saint-Maurice, Golfech and Tricastin nuclear power plants ».
These derogations are justified by the fact that” in the absence of temporary modification of the current thermal discharge limits, the operator would have to stop the operation of these nuclear power plants or reduce their production in order to limit the heating of the Gironde estuary for the Blayais, Rhône power plant for the Saint-Alban-Saint-Maurice and Bugey power plants, the Garonne for the Golfech power plant and the Donzère-Mondragon canal for the Tricastin nuclear power plant », even though ” the maintenance of a minimum level of electricity production by the reactors of nuclear power plants (…) constitutes, with regard to the security of the electricity network, a public necessity ». And for good reason, more than half of the 56 nuclear reactors are already shut down due to maintenance or corrosion problems.
But this decision is not without ecological consequences, as reported by the NGO France Nature Environnement (FNE). ” The Bugey nuclear power plant has just been authorized to discharge water that is warmer than usual. This is not going to help improve biodiversity in the Rhône, which suffers from summer heat waves, like all French rivers. », she reacted on Twitter. The decree ensures that the implementation of these measures will be ” associated with an enhanced environmental monitoring program ».