ASN Report on the State of Nuclear Safety and Radiation Protection in France in 2022: an exceptional year and context

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ASN underlined that in 2022, the standard of safety of the nuclear installations and radiation protection in the industrial, medical, industrial and radioactive substance transport sectors remained satisfactory ^[1].

The year 2022 was nevertheless marked by several unprecedented problems in nuclear facilities, such as the number and duration of the EDF reactor outages during the winter of 2022-2023, and the vulnerabilities that persist in the fuel cycle facilities. These events confirm the importance of having safety margins and anticipating the safety and radiation protection challenges ahead comprehensively, in an interdependent nuclear system.

The summer of 2022 witnessed an exceptional heatwave and drought which led ASN, for the first time since 2003, to take exceptional decisions to waiver thermal discharge requirements and keep five reactors in operation. This situation had no impact on nuclear safety.

The year also saw debates around the French energy mix and the new prospects for nuclear energy, whether considering the continued operation of the existing facilities or the construction of new ones. They take place in the wake of the French President's speech in Belfort and against the backdrop of the war in Ukraine and international tensions, which serve to further highlight the issues of energy sovereignty and reindustrialisation.

In the last two years, to go beyond its traditional duties of inspecting licensees and manufacturers, and with the prospect of the development of a new nuclear programme, ASN has conducted sampling inspections in the nuclear subcontracting chain as a whole and on project management by the licensees. . The results of the inspections carried out in 2022 show that the technical capabilities of the nuclear supply chain remain a major point on which attention must be focused.

The topical subjects

An unexpected phenomenon of stress corrosion on the nuclear fleet provides a reminder of the need for safety margins

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In 2022, operation of the EDF reactor fleet was marked by the consequences of the discovery of a stress corrosion phenomenon on systems connected to the primary cooling system. ASN considers that the steps taken by EDF in response to the situation were satisfactory as regards safety. They served to establish a diagnosis of the facilities concerned, provide initial explanations of the phenomenon, identify the parts of the system and the welds most sensitive to stress corrosion, and lastly to establish a prioritised inspection and repair strategy, which was recently adjusted and has been deemed appropriate by ASN.

This situation illustrates the electricity supply difficulties that could be encountered in the event of a generic problem affecting several reactors simultaneously. Back in 2013 ASN had stressed the need for the electricity supply system to have sufficient margins to cope with an event of this type.

EPR Commissioning remains conditional on crossing the final milestones

In 2022, EDF continued the work with a view to the commissioning of the Flamanville EPR, and in particular the requalification of the facility following the modifications and repairs carried out. ASN nevertheless underlines that a significant amount of work remains to be done ahead of commissioning, to carry out the final hot testing campaign on site and to complete the nuclear pressure equipment conformity demonstrations.

Innovative small reactor projects raise unprecedented safety questions

In the present context where decarbonized energy production is the aim, Small Modular Reactors (SMRs) are attracting considerable interest worldwide, particularly in non-nuclearized countries. This must not however obscure the questions of security and nuclear safety raised by these reactors. In 2022, ASN continued its discussions with several French companies developing SMR projects involving different technologies. At the initiative of ASN, the French, Finnish and Czech nuclear regulators and their respective technical support organisations, started a preliminary examination of the main safety options of the Nuward project sponsored by EDF. The conclusions of their joint evaluation will be shared with the European nuclear safety authorities. In ASN's opinion, this type of practical initiative on sufficiently mature reactor designs constitutes a crucial step towards achieving greater convergence in the safety requirements for SMRs.

ASN's assessments

ASN exercises its oversight role using - in a manner that is complementary and tailored to each situation - the regulatory framework, individual resolutions, inspections and, if necessary, enforcement measures and penalties. ASN reports on its duties and produces an assessment of the actions of each licensee, in each activity sector. During the year 2022, ASN carried out 1,868 inspections in the areas of nuclear safety and radiation protection.

Oversight of the EDF facilities

ASN observes that the quality of operation of the nuclear power plants (NPPs) remained satisfactory in 2022. Nevertheless, the improvement in the quality of operation of some NPPs often proves to be slow (particularly in the case of Golfech and Gravelines in 2022 and Dampierre-en-Burly in early 2023).

ASN considers that the actions undertaken by EDF in response to the stress corrosion phenomenon were appropriate as regards nuclear safety, and that the cutting of pipe sections to carry out expert assessments was vital in order to determine an appropriate inspection and treatment strategy.

Oversight of the Orano facilities

The facilities operated by Orano, located on the La Hague, Tricastin and Marcoule sites, all present major safety implications but of different types, both chemical and radiological. Despite progress made in 2022 in the management of radioactive substances on the La Hague and Tricastin sites, and a major action plan to overcome the Melox production difficulties and the risks of the radioactive material storage facilities reaching maximum capacity, ASN underlines that there is still very little leeway in the functioning of the "fuel cycle", which remains a point requiring particular attention. ASN once again insists on the need to significantly increase the forward-looking initiatives and to improve the quality of the files submitted.

Oversight of the CEA facilities

The large majority of the nuclear facilities operated by the Alternative Energies and Atomic Energy Commission (CEA) are concerned by the licensee's decommissioning and radioactive substance management strategy. ASN observes that the safety of these facilities remains under control, but that the decommissioning and waste management projects display contrasting results and remain exposed to major contingencies (technical, contractual, financial). In this respect, ASN considers that the CEA must increase its control over these projects.

ASN moreover considers that the implementation of the "major safety undertakings" supervised as the highest echelon of the CEA, improves tracking of the actions concerning the most important nuclear safety and radiation protection issues.

Oversight of Andra's facilities

ASN considers that filing of the Cigéo creation authorisation application on 16 January 2023 represents a major milestone in the management of high- and intermediate-level long-lived waste. The conditions of examination of this application, which will span a period of at least three years, were defined in 2022 in collaboration with all the stakeholders and the French High Committee for Transparency and Information on Nuclear Safety (HCTISN). They will enable all the technical questions from the stakeholders to be taken into account in each step of the examination process.

ASN assessments concerning the medical sector

ASN considers that the standard of radiation protection in the medical sector remains good, despite some persistent weaknesses. The extreme pressure, particularly with regard to human resources, has led to the implementation of new work organisations, notably multi-site or calling on outside contractors. ASN has been particularly vigilant in ensuring that these new organisations do not result in a deterioration in radiation protection.

Based on observations from the inspections conducted in 2022 and an analysis over the 2018-2022 period, the radiation protection culture can be improved, particularly in the areas of fluoroscopy -guided interventional practices, for which training of the personnel in patient and worker radiation protection is struggling to progress.

The number of significant radiation protection events remains very low considering the large number of procedures performed, but the recurrence of certain events shows that the lessons learned from previous events are sometimes forgotten. These events remind us that the radiation protection culture can never be taken for granted; it must be actively maintained.

ASN promotes all actions that could contribute to the application of the principles of justification and optimisation. On this account, ASN has emphasised the importance and value to be gained from external clinical peer reviews, particularly in fields with high stakes, and supports their implementation in radiotherapy and computed tomography in particular. Furthermore, given the large proportion of radiotherapy treatments in oncology and the improvement in survival rates, it is all the more important to assess the long-term radiation-induced effects. ASN thus points out the need to set up follow-up registers to allow a better evaluation of these long-term radiation-induced effects, particularly for the new practices such as hypofractionation and flash radiotherapy.

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