The ramp-up of nuclear thermal power reached 100% at11:37 on Sunday, EDF said.
It added: “Reaching the 100% mark for the first time enables testing of equipment at full power, taking of measurements and verifying that everything is functioning properly. Over the coming weeks, and as part of the start-up programme, the power of the reactor will vary to continue testing at different power levels and an operation will be carried out on an internal electrical substation. This milestone reflects the commitment and expertise of the teams of EDF and of its industrial partners over the past months to ensure the safe start-up of the reactor.”
This is the latest stage of commissioning the 1650 MWe (gross) pressurised water reactor. The Autorité de Sûreté Nucléaire et de Radioprotection (ASNR) authorised the start of commissioning in May last year. That authorisation was followed by fuel loading, with the start-up process beginning in September 2024.
Starting up a nuclear reactor takes place over several months. Gradually, the circuits are brought up to temperature and pressure, power tests are carried out, and then the production unit is connected to the electrical grid – which happened with Flamanville 3 in December 2024.
The power is then increased in a series of stages, with numerous tests carried out at each level before the unit is cleared to move to the next stage. In January this year the French regulator gave permission for the reactor to go beyond 25% of its capacity, with tests and checks carried out through the year.
ASNR said: “During this phase, the physical testing of the core continued at different power levels and were supplemented by tests such as islanding (isolation from the electricity grid while maintaining energy production for the plant’s own needs) or manual shutdown of the reactor.
“The ASNR carried out several inspections of the reactor from the 25% power level. It also analysed the significant events declared by EDF and checked the corrective actions implemented. The ASNR has not identified any element that could call into question the possibility of continuing to ramp up the reactor beyond 80% of its nominal power.
“ASNR will continue to monitor the subsequent stages of the reactor ramp-up until the end of the start-up tests.”
It said its new approval “allows EDF to continue ramping up the reactor until it reaches its nominal power, and then to complete the start-up test programme”.
Construction work began in December 2007 on the third unit at the Flamanville site in Normandy in northern France – where two reactors have been operating since 1986 and 1987. The dome of the reactor building was put in place in July 2013 and the reactor vessel was installed in January 2014. The reactor was originally expected to start commercial operation in 2013 but has faced a series of delays.
The first EPR units came online at Taishan in China, where unit 1 became the first EPR to enter commercial operation in 2018 followed by Taishan 2 in September 2019. In Europe, Olkiluoto 3 in Finland entered commercial operation in 2023, and two units are currently under construction at Hinkley Point C in the UK.
