The process of loading fuel assemblies into the core of the Flamanville 3 EPR reactor in France has been completed ahead of its start-up. The 1650 MWe (gross) pressurised water reactor is expected to reach 100% output before the end of the year.

The Flamanville EPR (Image: Alexis Morin and Antoine-Soubigou/EDF)

In a 22 May LinkedIn post, manager of the Flamanville 3 project Alain Morvan said: "Fuel loading into the Flamanville EPR reactor vessel is now complete ... since 8 May, the 241 fuel assemblies, each approximately 5 metres high and weighing nearly 800 kg, were transferred one by one under water, through the transfer channel which makes the link between the fuel storage pool and the reactor pool where the vessel is located.

"The handling of the fuel assemblies was carried out with the greatest rigour by the EDF teams; the Framatome teams ensured the neutron monitoring of the reactor core; and those from REEL ensured the proper functioning of all the machines used for these operations. Loading the reactor concludes the first stage of start-up."

Morvan said the reactor vessel will shortly be closed, after which the temperature and pressure in the primary circuit will then gradually be increased to 303°C and 155 bars, respectively, when it will attain 'hot shutdown' conditions.

The first nuclear reaction - referred to as 'divergence' - will be carried out in the coming weeks, he added. The reactor will then gradually increase power to 25% capacity, at which point the unit will be connected to the electricity grid. The EPR will continue to increase output in stages, reaching 100% capacity before the end of the year. "During these several months of exciting tests, numerous checks will be carried out to test around 1500 safety criteria," Morvan noted.

Construction work began in December 2007 on the third unit at the Flamanville site in Normandy - 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.