The calculation of provisions incorporates a level of risks and unknowns as appropriate to the operations concerned, together with uncertainty factors such as:
The value of pensions and other long-term and post-employment benefit obligations is based on actuarial valuations that are sensitive to all the actuarial assumptions used, particularly concerning discount rates, inflation rates and wage increase rates.
The principal actuarial assumptions used to calculate these post-employment and long-term benefits at 31 December 2022 are presented in note 28.4. These assumptions are updated annually. EDF considers the actuarial assumptions used at 31 December 2022 appropriate and well-founded, but future changes in these assumptions could have a significant effect on the amount of the obligations and on EDF’s net income.
As explained in note 3, the quantities of energy supplied but not yet measured and billed are calculated at the reporting date based on consumption statistic models and selling price estimates. Determination of the unbilled portion of sales revenues at the year-end is sensitive to the assumptions used to prepare these statistics and estimates.
The fuel assemblies required for the first fuel load continued to arrive during the first half of the year, and the entire first core is now stored in the Flamanville 3 reactor building pool.
The process of repairing the penetration welds on the main secondary circuit using remote-controlled robots was approved by the ASN on 19 March 2021, several weeks behind the expected date, and work began on the eight welds that were not compliant with the break preclusion principle. All eight were repaired in 2021, then subjected to stress-relieving heat treatment. Demonstration of the qualification of the stress-relieving heat treatment for repairs of VVP (steam discharge pipework circuit) penetration welds was validated by the ASN, which issued authorisation for its use in late 2021. Furthermore, four ARE (steam generator water supply circuit) penetration welds also required repair, and qualification of the repair process is under way at the ASN. This process is an adaptation of the process used for VVP penetration weld repairs.
For the non-penetration welds located on the main secondary circuit that had quality deviations (this concerns 45 VVP welds and 32 ARE welds), the ASN issued approval in April 2021 for the repair of a third batch of 6 welds. In the 3 batches authorised to date, 12 weld upgrades have been completed. In April the ASN gave approval for the related regulatory checks, which are currently in process.
In total, a hundred welds (penetration and non-penetration) on the main secondary circuit were concerned by repairs to the VVP and ARE pipework. The final stage of repair for most of these welds will be an optimised stress-relieving heat treatment, prior to the final verification. Repairing these welds remained one of the key challenges on the Flamanville 3 critical pathway.
On 2 March 2021 EDF declared a significant event to the ASN, concerning incomplete application of the 2006 design standards when installing three nozzles on the main primary circuit (these nozzles connect auxiliary circuits to the primary circuit). At the request of the ASN, three scenarios were examined by the Group’s engineering teams. A file was sent to the ASN on 21 June 2021, stating that EDF’s chosen solution was to install a “containment collar”, and asking the ASN for its position on this solution, so that all the design and procurement activities could be launched by the end of 2021. In a letter of 8 October 2021 the ASN indicated that it had no objections to this solution in principle. Nonetheless the design file for the containment collar will be examined by the French Radiation Protection and Nuclear Safety Institute IRSN (Institut de radioprotection et de sûreté nucléaire).
After corrosion was observed on pressuriser valves at the EPR at Olkiluoto (Finland), EDF carried out equipment checks and also detected traces of corrosion on the Flamanville EPR’s valves. The material used for certain components of the pilot control valves was changed accordingly. Several corrosion stress tests were conducted to select the best material. The ASN was regularly informed of the technical choices, and made no objection to this strategy. The ASN and the IRSN also continued their examination of the operation and reliability of the pressuriser valves. EDF is due to respond to the IRSN’s most recent questions so that it can finalise examination of the valve design.
As the work advanced, new technical matters emerged that could increase the completion cost and the risk of deferred timelines. In view of the progress made on operations and preparations for start-up, on 12 January 2022 EDF adjusted the schedule for the Flamanville 3 project. The fuel loading date was deferred from late 2022 to the second quarter of 2023, and the estimated completion cost revised from €12.4 billion to €12.7 billion (in 2015 euros, excluding interim interest). The project has no remaining margin in its schedule or completion cost.
Before loading the fuel into the reactor vessel and carrying out the overall start-up tests, several operations remained to be carried out, mainly:
The main progress on the Flamanville 3 project in 2022 concerned:
