CASE. Nuclear: heat wave, maintenance, cracks… as the power plant fleet comes under tension
Several nuclear reactors have been forced to reduce their output due to the high temperatures of the waterways used to cool them. Add to that maintenance delays, aging power plants, recently discovered cracks and EPR delays associated with the global energy crisis.
At a time when the world has plunged into an energy crisis sparked by the war in Ukraine, France’s nuclear power – capital in electricity generation as it accounts for about 67% of total production – is a cause for concern.
Covid and cracks
The fleet of 56 aging nuclear reactors has been under tension for several months. Concerns started with the Covid-19 epidemic disrupting the facility’s usual maintenance schedule (decennial inspections). Consequences: The availability of the nuclear fleet was lower than average as the successive restrictions shifted the maintenance of certain reactors to the winter period, which was forced to a standstill.
Another setback, the discovery in October 2021 of cracks in an emergency cooling circuit of reactor No. 1 of the Civaux power plant. This discovery prompted EDF to shut down this reactor and then 11 others for safety reviews (Civaux 2, Chooz B1 and B2, Penly 1, Chinon B3, Bugey 3 and 4, Cattenom 3, Flamanville 1 and 2, Golfech 1). The Institute for Radiation Protection and Nuclear Safety (IRSN) has described this phenomenon as “harmful” because it is difficult to detect at an early stage, and the Nuclear Safety Agency (ASN) has ruled that it is “a serious and unprecedented event is whose full treatment will take several years”…
EDF, ASN and IRSN believed that this phenomenon of stress corrosion of austenitic stainless steel was unprecedented, but the Global Chance Association, in a report published on June 15, revealed that such a phenomenon occurred as early as 1998 and that there was even precedent in 1975 took place at American power plants. ASN responds that the 1998 and 2021 rifts are of different natures.
These cracks are also reminiscent of those of a different nature that will affect future new-generation EPR reactors, including that of Flamanville. Could these issues ultimately force a review of the 10-year extension of 32,900-megawatt-MW reactors originally designed to last 40 years?
The effects of the heat wave
In addition to these problems, which have resulted in 48% of the fleet being idle and therefore forecasting a drop in power generation forecasts, EDF is facing a heatwave this summer. Last week, several EDF nuclear reactors had to cut production due to the high temperatures of the waterways used to cool them. Each plant has its own legal limit values for the water outlet temperature, which must not be exceeded in order not to heat up the surrounding water and to protect the fauna and flora. The power plants actually pump water to cool the reactors before rejecting it. The regulations setting the discharge limit values also provide for higher limit values ”in exceptional climatic conditions”, as is currently the case in Golfech.
Rise in water temperature: “The Golfech power plant is not an issue,” says Migado, who oversees the fish farm
“The current exceptional climatic conditions are reflected in an increase in temperature of the Garonne, which has reached 28 degrees,” EDF announced on August 5. “At the request of the National Electricity Transmission Operator (RTE), production unit #2 of the Golfech power plant remains in production (minimum output)” (300 MW vs. 1,300 MW), EDF continued; the 1st reactor is being serviced…*
“RTE recognizes the need to keep the nuclear power plants of Blayais, Bugey, Golfech, Saint-Alban and Tricastin at a minimum level of electricity production until August 21st to ensure the security of the electricity network”, explains the ASN, which therefore adopted issued on August 4th a decision to temporarily change the thermal discharge limits of these power plants until September 11th, 2022 “accompanied by increased monitoring of the aquatic environment, especially fish life. »
Nuclear: The Garonne and her fish are monitored behind the Golfech nuclear power plant like milk on a fire
Because these water discharges from the power plants worry the fishing and environmental associations. “That doesn’t mean it prevents damage. In the long term we will see,” fears Roland Desbordes, spokesman for the Criirad.