[EPR Flamanville Series] ASN authorise commissioning of the Flamanville EPR reactor

The green light is given! On Tuesday, May 7, 2024, the French Nuclear Safety Authority (ASN) authorised the startup of the EPR at Flamanville. This authorisation enables EDF to load fuel into the reactor and commence the reactor’s startup operations.

It was through a statement on May 7, 2024, that the ASN “authorised the commissioning of the Flamanville EPR reactor. This authorisation allows EDF to load nuclear fuel into the reactor and to proceed with startup tests and then operation of the reactor.” This green light had been eagerly awaited for several weeks as EDF was ready to start. The ASN specifies that “This authorisation concludes the review conducted by the ASN, with the support of the IRSN, of EDF’s application for authorisation. The ASN also monitored the construction of the reactor and conducted nearly 600 inspections during this period.”

The authorisation issued by the ASN is accompanied by technical requirements that govern the conduct and monitoring of the startup tests after loading nuclear fuel into the reactor; specify how to incorporate lessons learned from the operation of other EPR-type reactors around the world; define the timeline for replacing the exchangers between the the component cooling water system (RRI) and essential service water system (SEC) to ensure adequate performance throughout the life of the installation; define the deadline for replacing the bodies of two safety valves in the main secondary circuits.

The ASN finally specifies that monitoring will be continuous throughout the startup with necessary approvals at several stages such as the first divergence (the first nuclear reaction), reaching 25% power, and then 80% of the reactor’s capacity.

It’s Now Up to EDF to Proceed with Core Loading

The responsibility now falls to EDF to load the core. It’s worth noting that the fuel has been on-site since 2022, and the neutron sources were welded last February. The Flamanville EPR project began in 2007, and the first nuclear reaction will officially mark the end of this construction phase. Once operational, the reactor will be the most powerful in the French fleet, producing 1,650 MW, surpassing the four 1,450 MW N4 series units currently in operation. It will be the fourth EPR to enter service worldwide, following the two EPRs at Taishan in China and the Olkiluoto EPR in Finland.

TVO, the Finnish electric utility operating the latter unit, explained last January that: “Since its startup, OL3 has operated stably except for two interruptions caused by technical issues with the turbine.” TVO adds, however: “production was interrupted for 84 hours out of a total of 6,155 hours, equivalent to 1.4% of unplanned production stops.” ■