Unit 3 of the Flamanville NPP in in the Cotentin region of Normandy in northern France has been connected to the grid for the first time, EDF announced.

The 1630 MWe (net) European Pressurised Reactor (EPR) was launched in September but was stopped the following day due to an “automatic shutdown”. It resumed a few days later, and since then generation has been gradually increased to enable the reactor to be connected to the electricity network.

The European Pressurised Reactor project was launched in 1992 and was designed to relaunch nuclear power in Europe after the 1986 Chernobyl catastrophe in Soviet Ukraine. Construction began in 2007 at the Flamanville site – where two reactors had been operating since 1986 and 1987. However, the project was beset by numerous problems. The start-up came 12 years behind schedule after a plethora of technical setbacks which saw costs soar to an estimated €13.2bn ($13.76bn), four times the initial €3.3bn estimate.

The Autorité de Sûreté Nucléaire (ASN) in May authorised commissioning of the reactor, clearing the way for EDF to begin loading the 241 fuel assemblies into the reactor and to carry out start-up tests and subsequent operation of the reactor. In August EDF sent ASN the information required to issue an agreement for the first nuclear reaction (divergence) to proceed. This included results of the installation tests carried out since the commissioning authorisation. ASN authorised the launch of divergence operations in September and the EPR achieved first criticality. The subsequent test programme to achieve a power level of 25% was temporarily delayed by technical problems.

At that time, an EDF spokeswoman explained that reactor startup is a long process and an EPR is a complex machine, so it was not unusual to encounter technical problems during. The shutdown “proves the safety system is working well,” she noted.

Following the grid connection, EDF said in a statement: “Teams have achieved the first connection of the Flamanville EPR to the national grid … the reactor is now generating electricity. Since the first nuclear reaction in September … EDF teams have conducted a series of tests and inspections to gradually increase the reactor’s power.”

Luc Rémont, Chairman and CEO of EDF stated: “The coupling of the Flamanville EPR is an historic moment for the entire nuclear sector. I would like to salute all the teams who have met the challenges encountered during this project with the greatest tenacity and never compromising on safety.

EDF said that “in accordance with the startup operations, the phases of testing and of connection and disconnection to the grid will continue for several months, under the supervision of the ASN, until the reactor reaches 100% power. Starting up a reactor is a long and complex operation. It requires the full mobilisation of teams and is carried out at each stage with the highest level of safety and industrial reliability”. The reactor is expected to operate at 100% capacity until the first planned outage for maintenance and refuelling – the Visite Complète 1 (VC1).” EDF said the VC1 “should mainly take place in 2026” and that the electricity produced by then will be around 14 TWh.

President Emmanuel Macron said in a statement on LinkedIn that this was a “great moment” for France noting that the EPR is “one of the world’s most powerful nuclear reactors”. He added: “Re-industrialising to produce low-carbon energy is French-style ecology. It strengthens our competitiveness and protects the climate.”

Macron earlier decided to boost nuclear power by ordering six EPR2 reactors with options for eight more, which could cost tens of billions of euros. In 2022, he called for a “renaissance” for the nuclear industry to transition away from fossil fuels. “What we have to build today is the renaissance of the French nuclear industry because it’s the right moment, because it’s the right thing for our nation, because everything is in place,” he said at the time.

EPRs are currently operating in China and Finland. The first EPR began operating at China’s Taishan NPP with unit 1 beginning commercial operation in 2018 followed by Taishan 2 in September 2019, some five years behind schedule. Construction of Taishan 1 started in November 2009. The project was led by TNPJVC, a joint venture founded by CGN (51%), EDF (30%) and a regional Chinese utility called Yuedian (19%).

Construction of the EPR at unit 3 of Finland’s Olkiluoto NPP began in 2005 and various setbacks and delays meant the plant was some 14 years behind the original schedule and significantly over budget. OL3’s final price tag was put at around $11bn ($12bn), some three times the initial estimate. Two EPR units are currently under construction at Hinkley Point C in the UK.