The 1,630-MW EPR plant, which is already a decade behind schedule and has been dogged by repeated cost overruns, is now expected to start operations in the first quarter of 2024 and cost €13.2bn, EDF said.
In January EDF had forecast construction costs of €12.7bn and said fuel loading at the plant would begin in the second quarter of 2023. Nuclear fuel loading is now scheduled for the first quarter of 2024.
The French state power company said the revised scheduled is mainly due to additional studies needed to establish a new process for the stress-relieving heat treatment of some welds that have been upgraded in the last two years, EDF said.
Stress-relieving heat treatment is a process carried out after welding to relieve residual welding stresses and achieve the right mechanical characteristics for the welded part.
The work is related to 150 thermal treatments needed for some welds so they are resistant enough when the reactor produces power.
The work, which follow repairs on some faulty welds, was interrupted last summer and will start again in early 2023.
“The teams have now moved on to the final stage of the stress-relieving heat treatment of the upgraded welds and to the stage of closing the main secondary circuit,” EDF said.
Vessel Head Closure To Be Replaced After Startup
EDF said it will also comply with a request by France’s nuclear regulator ASN to replace the reactor’s vessel closure head by the end of 2024, which would entail a first mandatory stoppage only some months after startup.
According to EDF, the last few months have seen further “strategic achievements” in the pre-operation phase of the Flamanville EPR including the “complex work” of upgrading the main secondary circuit penetration welds, all of which have been deemed safety compliant.
System performance testing of electrical equipment and fuel loading operations have been completed and deemed compliant with requirements.
According to the International Atomic Energy Agency’s reactor database, construction of Flamanville-3 began in December 2007.
France’s nuclear production share is about 70% – more than any other country – but it has planned to reduce this to 50% by 2035. The country has a fleet of 56 commercial reactors, second only to the US, which has 94.
In February French president Emmanuel Macron announced plans to relaunch the country’s commercial nuclear programme with the construction of at least six new nuclear power reactors – and the possibility of eight more for a total of 14.
Macron said the new plants would be built and operated by EDF and that tens of billions of euros in public financing would be mobilised to finance the projects and safeguard EDF’s finances.
File photo of construction at Flamanville-3 with the Flamanville nuclear station’s other two plants in the foreground. Courtesy EDF.