Agnès Pannier-Runacher explains the choice of Bugey for the third pair of EPR2 plants in France

The first unit of the third pair of EPR2s in France will start up in 2042 at the Bugey site, chosen in preference to Tricastin. Agnès Pannier-Runacher asserts that the Bugey site is the best prepared from a technical point of view, enabling work to start more quickly.

France’s new nuclear reactor construction program is taking shape. EDF has just submitted its application for authorization to build two EPR2s at Penly (Seine-Maritime), and a second pair of reactors is already planned for Gravelines. On July 19, the latest Nuclear Policy Council (CPN) announced the choice of Bugey (Ain), located on the Rhône, for the third pair. The timetable envisages the commissioning of the first unit as early as 2042. The site was in competition with Tricastin (Drôme).

Visiting the Bugey site on Monday, July 24, Energy Minister Agnès Pannier-Runacher explained the choice of the site by “technical challenges” to “keep to schedules”. In an interview with journalists, they added: “The Bugey site was more ready than Tricastin, so it was a rational choice”. The Minister’s office added: “During the last few months of analysis, the preferred site was Bugey (…), which means that construction can be launched more quickly since further studies are required on the Tricastin site”.

However, the Tricastin site has not been definitively ruled out. Although the program’s first phase includes six EPR2s, the French President had already asked in his 2022 speech in Belfort to study the feasibility of building eight additional reactors.

Bugey and water from the Rhône

Compared with Penly and Gravelines, the Bugey site is unique in that it is located on the banks of a river, whereas Penly and Gravelines are by the sea. In the context of global warming and increased drought in France, access to the cold spring must be closely monitored. As a result of climate change, some are already warning of a lack of cooling water in the Rhône in the coming years. In reality, this risk is relatively low.

The Bugey site already has four reactors, two open-cycle and two closed-cycle. Today, the plant’s net water withdrawal (i.e. consumption) is about 1m3/s. bouIn relation to the river flow at the nearest hydrometric station (Lagnieu), this represents between 0.1% and 0.3% of the flow of the Rhône, depending on the month.

Impact of two EPR2

The project owner, EDF, has anticipated the impact of the presence of two EPR2s. They would withdraw 10m3/s and release 80%. The net withdrawal would therefore be around 2m3/s, which, as it stands, leaves consumption below 1% of the flow for the entire power plant.

What about changes in the flow of the Rhône over the coming decades? According to studies carried out by the Agence de l’eau Rhône Méditerranée for the period 2041-2070 (French version), Lagnieu’s flow will increase in winter (median February +38%) and decrease in summer (median August -19%). The Agence reminds us that irrigation is the main user of the Rhône water.

To learn more about water consumption by nuclear reactors, you can consult the Sfen study on the subject. It details plant-by-plant water withdrawals and consumption on a monthly basis.■

By Ludovic Dupin (Sfen)

Photo: Agnès Panier-Runnacher visiting Bugey on July 24, 2023 – @MDE