For its part, ASN informs the public on asn.fr of significant events rated level 1 or more on the INES scale (International Nuclear and Radiological Event Scale, graded from 0 to 7 in increasing order of severity). ASN requirements concerning repairs ASN published its Guide No. 21 on 6 January 2015 regarding the handling of conformity deviations. This Guide specifies ASN’s requirements concerning the correction of non-conformities and presents the approach expected of the licensee in accordance with the principle of proportionality. This is based more specifically on an assessment of the potential or actual consequences of any deviation identified and on the licensee’s ability to guarantee the safety of the reactor in the event of an accident, by taking appropriate compensatory measures. The Guide also recalls the principle of the correction of compliance deviations as soon as possible and in any case defines the maximum times allowed. 2.4.8 Assessment of facilities compliance with the applicable requirements In the past, ASN has found that the organisational measures taken by EDF to deal with deviations were unsatisfactory and that the time taken to characterise, check and process the deviations did not always comply with the requirements of the Order of 7 February 2012. In 2019, EDF therefore revised its internal baseline requirements for management of deviations, in order to improve how they are processed and provide ASN with reactive information proportional to the safety implications. In 2022, ASN observed that the steps taken by EDF enabled the deviations to be corrected within the required time in most situations. These efforts will need to be continued in the coming years, notably on the occasion of the ten yearly outages. Significant events concerning several reactors were once again reported in 2022 following the detection of conformity deviations; some of these deviations date back to the construction of the reactors, while others arose when making modifications to or performing maintenance on the facilities. ASN will continue to be particularly attentive to the conformity of the facilities in 2023 and will in this respect continue its inspections of the condition of equipment and systems. ASN observes that certain systems linked to the “support”, “reactivity control” and “cooling” safety functions are subject to recurring unscheduled unavailability, in the same way as in 2020 and 2021. This is notably the case with the reactor component cooling systems, post-accident monitoring, reactor nuclear power measurement and rod cluster control, or the 48V direct current electrical production and distribution systems. Discussions with EDF will continue in 2023 in order to identify the root causes of the unavailability of these systems and check the pertinence of the measures envisaged by EDF to reduce their number. Notification of significant events by EDF Pursuant to the rules for the notification of significant events (see chapter 3, point 3.3), ASN received 687 Significant Safety Event (ESS) reports from EDF in 2022, along with 136 Significant Radiation Protection Event (ESR) reports and 56 Significant Environmental Protection Event (ESE) reports. The number of significant events fell by about 9.7 % in 2022 by comparison with the previous year, in particular the ESS (746 in 2019, 740 in 2020, 762 in 2021). Graph 1 shows the trend since 2012 in the number of significant events reported by EDF and rated on the INES scale. Graph 2 shows the trend since 2012 in the number of significant events according to the notification field: ESS, ESR and ESE. Events not rated on the INES scale are also taken into account. Significant events affecting several nuclear reactors are grouped under the term generic significant events. In 2022, 21 events of this type were reported in the field of nuclear safety (29 in 2019, 26 in 2020, 31 in 2021). 2.5 Prevention and management of environmental and health impacts and non-radiological risks 2.5.1 Discharges, waste management and health impacts Limiting water intake and environmental discharges NPPs discharge liquid and gaseous effluents. These effluents, which can be radioactive or chemical, are created by the actual operation of the reactor, primarily the operations designed to ensure the radiochemical quality of the MPS system, the chemical conditioning of the systems in order to contribute to their good condition, the production of demineralised water to supply certain systems, biocidal treatments and effluents from the site’s wastewater treatment plant. For each site, ASN sets the limit values for water intake and discharge of effluents on the basis of the best available technologies in technically and economically acceptable conditions, taking into consideration the characteristics of the installation, its location and the local environmental conditions. ASN also sets the rules concerning the management of detrimental effects and the impact on health and the environment of the reactors. These requirements are notably applicable to the management and monitoring of water intake and effluent discharge, to environmental monitoring and to information of the public and the authorities (see chapter 3, point 4.1). In setting these requirements, ASN uses OEF from all the reactors as the basis, while also taking account of operational changes (change in conditioning of systems, anti-scaling treatment, biocidal treatment, etc.) and changes to the general regulations. REINFORCED OVERSIGHT OF SUPPLIERS OF EQUIPMENT IMPORTANT FOR NUCLEAR SAFETY In 2022, ASN continued to reinforce its oversight of the EDF procurement chain for equipment important for safety intended for NPPs. In 2022, ASN therefore carried out 48 inspections, most of them in manufacturing plants. During these inspections, ASN examined compliance with the regulatory requirements during manufacturing operations, the ability of the suppliers to manufacture equipment meeting the safety requirements and how the risk of fraud is addressed. ASN also checked EDF’s monitoring of its suppliers and their subcontractors. ASN also inspected the purchasing process put into place by EDF, to ensure that the safety issues are correctly addressed when EDF places contracts with its suppliers, as well as throughout the execution of the contracts. Finally, in 2022, ASN continued to exchange with its counterparts on the subject of supply chains, notably within the Committee on Nuclear Regulatory Activities (CNRA), which offers a forum for sharing the conclusions of the inspections performed in the various factories around the world. ASN Report on the state of nuclear safety and radiation protection in France in 2022 301 • 10 • The EDF Nuclear Power Plants 10 01 07 08 13 AP 04 06 12 14 03 09 05 11 02
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