Start 2025: EDF’s programme to improve the success of reactor shutdowns

Start 2025 is EDF’s ambitious plan to enhance the performance of reactor shutdowns and, consequently their output. Initiated in 2019, it encompasses five years of on-site efforts to implement the program across all sites in France. As of now, 80% of the solutions have already been deployed.

EDF aims to ensure and increase its production. To achieve this, the production teams focus on optimizing reactor shutdowns through the Start 2025 program. This takes place in a demanding context. The power plants are facing an unprecedented industrial workload while €4.7 billion is invested annually in nuclear park maintenance. Following the French Nuclear Safety Authority’s (ASN) recommendations, the safety ambitions have never been higher than in this fourth periodic review, which began in February 2021 for the 900 MW reactors and will soon extend to the 1300 MW ones. Currently, the volume of activities for these shutdowns is six times higher than that of the third review.

Since 2020, production sites have also had to deal with unprecedented events such as COVID-19 and stress corrosion cracking (SCC), which have affected the planning of activities and maintenance shutdowns.

Optimizing Shutdowns: A Key Challenge for Strengthening Production

A reactor’s life is characterized by two main phases: operation and outage. The former lasts 12 to 18 months and is fixed, as it responds to physical constraints related to the fuel. Over a 10-year cycle, three types of reactor shutdowns are planned. Simple refuelling outages (SRO) and partial inspections (PI) alternate to refuel and perform maintenance operations. Decennial inspections (DI) additionally allow for safety modifications and checks. The goal is to optimize and align the outage schedules with the regulatory deadlines.

Start 2025’s Four Strategic Axes

“Producing well starts with successful outages,” explains Étienne Dutheil, EDF’s Director of the Nuclear Production Division. This is the guiding principle of Start 2025. Reactor shutdown is a central element of life at nuclear production sites, hence the need to maximize their optimization. “Everyone contributes to the success of the outages on the sites,” he assures. Consequently, before the shutdowns during production, months of work enable better anticipation and successful completion of these outages.

Start 2025 has four objectives to optimize outages. It was developed in the most collaborative manner possible, calling upon solutions primarily from on-site experience. First, the project aims to highlight the skills and expertise of on-site teams. This involves knowledge sharing within working groups and a reinternalization of specific services. Second, the project contributes to operational efficiency through classifying methods in preparing for shutdowns and optimizing the route and supply of spare parts.

Third, the re-emphasis on attentive management yields more on-site solutions and empowers teams at all levels. Fourth, it was necessary to revise the organization to match the industrial reality of each site: appropriately sizing teams for each reactor and establishing “park” teams for support.

Promising Results Already

Étienne Dutheil is enthusiastic: “Start is producing results.” The overall performance of shutdowns and production is already improving. Many sites, like Paluel, have set historical records for outage durations. Moreover, the first key milestone (beginning of reactor unloading at shutdown and disconnection from the grid) has been met in over 70% of outages, compared to less than 10% in 2021 and 40% in 2022. There has also been a one-third reduction in outage extensions since 2022.

“The production performance is increasing by making reliable reactors available to the grid,” asserts Étienne Dutheil. Indeed, the rate of unplanned unavailability between 2022 and 2023 is less than or equal to 3.5%. This also allows for better availability during cold seasons, with an increase of 5 to 10 GW compared to winter 2022. Finally, production ranges of 300 to 330 TWh in 2023, 315 to 345 TWh in 2024, and 335 to 365 TWh in 2025 are already confirmed thanks to this performance gain.

Increasing Power to Go Further

Can we now expect an increase in reactor power? This is what EDF is considering. In addition to Start 2025, two other solutions could help reach the goal of 400 TWh by 2030. The first, more “simple,” involves modernizing turbines. It does not require a dialogue with the ASN and is already in place on nine reactors of 900 MW. The second requires safety examinations and involves increasing the thermal power of the boiler, which will deliver more power to the turbine and alternator. ■

By François Terminet (Sfen)

Photo: Major refurbishment work at the Paluel nuclear power plant (Seine-Maritime) – ©Mouret.Thierry/EDF