France’s Framatome has asked for more time to change the nuclear vessel closure head at the EPR nuclear reactor under construction at unit 3 of the Flamanville NPP. Flamanville 3, which is already some 10 years behind schedule, is expected to start operations in the first quarter of 2024. However, the Autorité de Sûreté Nucléaire (ASN – Nuclear Safety Authority) had requested replacement of the reactor's vessel closure head by the end of 2024. This would mean the reactor would only operate for a few months before having to shut again for the work to be done. Framatome has now asked ASN to delay replacement of the vessel cover so it will coincide with the first fuel reloading rather than replacing it at the end of 2024.

In December, Plant owner/operator Electricite de France (EDF) said the schedule for construction of Flamanville 3 had been further delayed and that its estimated cost had also increased. The 1,600 MWe Flamanville 3 EPR, which started construction in 2007, was originally expected to cost €3bn and to be ready in four years. However, it faced a series of delays and technical issues.

EDF said nuclear fuel loading is now scheduled for the first quarter of 2024 -postponed from the second half of 2023. It put the estimated cost of completion at €13.2 billion ($14bn), up from the previous estimate of €12.7 billion. EDF said the revisions were mainly due to additional studies needed to establish a new process for the stress-relieving heat treatment of some welds that have had to be upgraded in the last two years.

ASN did not say whether it intended to approve Framatome's request to adjust the timeframe for the vessel closure head replacement, which had been determined before EDF announced the latest delay. However, ASN did say that France's nuclear safety needs a global and systemic review. ASN head Bernard Doroszczuk told a news conference that, by the end of 2024, EDF must explain how it plans to extend the life of its nuclear plants up to or beyond 60 years, in order to formulate a first position on the issue within a further two years.

The government is expected to present new energy and climate legislation this summer that will serve as the legislative framework for plans announced in February 2022 to start construction of at least six new EPR 2 reactors and to extend the lifespan of as many operating reactors as possible.

Doroszczuk said a nuclear safety review needs to anticipate the effects of ageing on nuclear installations as well as new challenges presented by climate change. "We need to identify for which components there may be a limit to their operating lifespan," he noted. He explained that some components are hard to replace, while other cannot be replaced, such as the reactor vessel and the reactor building.

"This is not something that can be worked out on the back of an envelope, we cannot decide in a few months whether it is feasible to go beyond 60 years," he stressed. Nevertheless, ASN said the safety of nuclear installations overall in 2022 was satisfactory, despite corrosion problems detected at some reactors.

Image: The Flamanville 3 reactor building (courtesy of Framatome)