In light of the fact that EDF is the world’s largest nuclear operator, exploiting global feedback and making comparisons with best practices internationally(1) represents an ongoing challenge to ensure that the EDF group is well positioned to be able to sustainably manage the risks associated with being the world leader;
The Group may not meet its nuclear power plants’ operating objectives in terms of safety and availability. It may also not be able to obtain approval to continue operating its reactors beyond the current planned expiry date, or even be authorised to operate them until that date in both France and the United Kingdom. In addition, the Group may not be able to control costs and deadlines for upgrading its operating fleet (“Grand Carénage” refurbishment projects in France).
Criticality in view of the control actions undertaken: Strong.
The fleet of nuclear reactors that the Group currently operates in France is highly standardised (see section 1.4.1.1.1 “EDF’s nuclear fleet in France”). This enables the Group, in particular, to achieve economies of scale, to apply improvements made to its newest reactors to all reactors and, in the event of a reactor malfunction, to anticipate the measures to be taken in other reactors. But this standardisation has a potential parallel risk of the dysfunction being common to several reactors or to a generation or series of reactors (see section 1.4.1.1.2 “Operation and technical performance of the nuclear fleet”).
The Group cannot guarantee that it will not be required to make significant or costly repairs or modifications to all or some of its plants, or that events will not occur that may have an impact on the operation of its plants or their output or cause a temporary or permanent shutdown of all or some of its plants. Thus, the deviation related to a steam generator (SG) weld stress relief process which was detected and reported to the Safety Authority in the summer of 2019 concerned SGs installed on 6 reactors of the nuclear fleet in operation in France and the Flamanville 3 EPR. Framatome is expanding the investigation to include other stress relieving processes.
During the periodic reviews carried out during the ten-yearly inspections and following the Fukushima accident in Japan, the Group drew up a major work programme, called “Grand carénage”, the principle of which was approved by the Board of Directors (See section 1.4.1.1.2). The potential risks of the latter include a possible delay in the appraisal of the authorisations required to start operations, in particular as regards the authorisations expected from the French Nuclear Safety Authority (ASN). Such uncertainties may also concern the manufacture and delivery on site of new equipment or work carried out on-site in a situation where a large number of industrial operations are being carried out at the same time.
The ASN decides on the measures taken by the operator and may give additional instructions for each reactor and for each authorisation stage. Solutions are being studied to demonstrate the capacity of non-replaceable equipment such as the containment building and reactor vessels, to ensure their operation up to 60 years. These studies, which are based on data available in France but also internationally(2) make it possible to confirm the safety margins available for the operating periods under investigation but may also lead to the need to adopt additional protective measures, if necessary, to be taken on the existing fleet, which could have consequences on its performance.
In order to postpone the construction of new units and related investments, and to continue to benefit from low-carbon generation and cash flows from its existing fleet, the Group has been aiming for several years to extend the operating life of its nuclear fleet in France beyond 40 years, a period already exceeded in France for six reactors.The fourth ten-yearly inspection of the 900MWe reactor series (VD4-900), like the previous ones, includes, on the one hand, a verification of the compliance of the facilities with the current reference design and, on the other hand, a safety reassessment. This makes it possible to increase the level of safety by taking into account, on the one hand, international best practices and, on the other hand, the condition of the facilities, the experience acquired during operation and the evolution of the knowledge and rules applicable to similar facilities. As part of this process, the ASN could prescribe significant additional amendments.
Concerning the fourth review of the 900 series, the Permanent Group (GP) regarding the V4 closing is scheduled for September 2020. The ASN will present its generic opinion, in particular on the adequacy of the amendments initiated by EDF. Starting in March 2020, EDF is expected to have initial discussions with the ASN on its future opinion. The formal ASN post-Permanent Group opinion is expected in 2021; consultations will be held with the College of Commissioners and the public beforehand. The ASN shall issue authorisations for continued operation on a reactor-by-reactor basis, following the examination of a periodic review report, taking into account the results of the inspections and requalification tests. For Tricastin 1, the VD4 (pilot plant) started on 1 June 2019 and ended with re-coupling on 23 December 2019, after the ASN had given its authorisation to restart. The periodic review report is scheduled for February 2020 and the public inquiry will take place in 2021, after the generic DSA notice on the VD4 has been issued. The ASN opinion on the TN1 periodic review report is expected to be issued in late 2021 or early 2022. It cannot be ruled out that the ASN’s generic opinion on the 900MW PWR series includes additional requests that could lead to additional costs and delays.
In 2016, the Board of Directors considered that all the technical, economic and governance conditions necessary to align the depreciation period of the French nuclear fleet with the Group’s industrial strategy were met (see notes 1.3.2 “Judgments and estimates of the Group’s management” and 1.3.2.1 “Depreciation period for nuclear power plants in France” of the appendix to the financial statements). It therefore approved the extension in the consolidated financial statements of the depreciation period for 900MW PWR plants outside Fessenheim from 40 years to 50 years, without anticipating the decisions of the ASN on whether or not to grant a licence to continue operation on a reactor-by-reactor basis after each 10-year inspection. With regard to the Fessenheim nuclear power plant, EDF has sent to the French Minister for Ecological Transition and Solidarity and to the ASN the request to repeal the operating licence and the declaration of permanent shutdown of the two reactors, providing for the shutdown of Reactor no. 1 on 22 February 2020 and Reactor no. 2 on 30 June of the same year.
The accounting period of the other series of France’s nuclear fleet (1,300MW and 1,450MW), which are more recent, currently remains at 40 years. The subsequent extension of the depreciation period of these series nevertheless remains an industrial objective for the Group. This objective may not be achieved as the conditions are not in place at this stage.
In the United Kingdom, the ongoing analysis of graphite ageing in the RAG (Advanced Gas Reactor) reactor may lead to prolonged unavailability of the most sensitive reactors. The cracking of graphite subjected to irradiation must be carefully monitored, with inspections carried out regularly, and controlled by the office for nuclear regulation (“ONR”), to ensure that there is sufficient knowledge of the core to justify continued operation. Following this process, the two Hunterston B reactors (R3 and R4 reactors) were shut down for inspections in March and October 2018, respectively. Following further unfavourable findings, the shutdown of Hunterston B R3 had to be extended in order to prepare the grounds for continued operation, which were submitted to the UK regulator (ONR) in June 2019. The ONR approved the restart of R4 at the end of August 2019 for a short period ending in December 2019. The safety case for the R3 reactor is under review by the ONR; approval is expected in early 2020. This approval will affect the restart of Hunterston’s R3 and R4 reactors and may also impact the safety case for the operation of Hunterston’s twin Hinkley Point B reactors. Such approval may also not be obtained or may lead to early abandonment in the event of an unfavourable ONR decision.
The current planned operating period for the reactors in EDF Energy’s existing nuclear fleet ranges from 41 to 47 calendar years for advanced gas reactors (AGRs) and is 40 years for the Sizewell pressurised water reactor (PWR). Since EDF Energy acquired them, the operating lifespan of the AGR power plants has been extended by 10 years on average and the objective is to increase the operating life of the PWR power plant by 20 years after the currently planned 40 years (see section 1.4.5.1.2.1 “Nuclear generation”). Nevertheless, given the nuclear safety rules applicable in the United Kingdom and RAG reactor technology in particular, the Group cannot guarantee that EDF Energy will obtain the necessary authorisations from the ONR when the time comes to operate its existing nuclear reactors until the currently planned end of
(1) Exploitation of standards and feedback from the International Atomic Energy Agency and the World Association of Nuclear Operators (WANO).
(2) Six reactors in the US are being investigated for an extended operating life of 80 years: the Nuclear Regulatory Commission (NRC) staff has defined subsequent license renewal (SLR) to be the period of extended operation from 60 years to 80 years. https://www.nrc.gov/reactors/operating/licensing/renewal/subsequent-license-renewal.html.
