“Real-time” checks Carrying out periodic test and preventive maintenance programmes on the equipment and systems contributes to identifying deviations. Routine visits in the field and technical inspection and verification of activities considered to be important for the protection of people the environment are also effective means of detecting deviations. Verifications during reactor outages EDF takes advantage of nuclear reactor outages to carry out maintenance work and inspections which cannot be performed when the reactor is generating electricity. These operations more particularly correct already known deviations, but can also lead to the detection of new ones. Before each reactor restart, ASN asks EDF to list any deviations not yet remedied, to take appropriate compensatory measures and to demonstrate the acceptability of these deviations with respect to the protection of people and the environment for the coming production cycle. Ten-yearly verifications: conformity checks EDF carries out periodic safety reviews of the nuclear reactors every ten years, in accordance with the regulations (see point 3.2). EDF then carries out an in-depth review of the actual state of the facilities by comparison with the applicable safety requirements, more particularly on the basis of the in-service monitoring hitherto carried out, and lists any deviations. These verifications are supplemented by a programme of additional investigations, the aim of which is to check parts of the facility for degradation modes which are not covered by the inspections involved in the preventive maintenance programme. The additional verifications in response to ASN requests In addition to the steps taken by EDF with regard to its operating baseline requirements, additional checks are carried out at the request of ASN, whether, for example, with regard to OEF about events which have occurred on other facilities, after inspections, or after examination of the provisions proposed within the context of the periodic safety reviews. 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 proportionality principle. 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. 2.5.4 Assessment of oversight of facilities compliance with the applicable requirements Condition of equipment and conformity In the past, ASN has found that the organisational measures taken by EDF to deal with deviations comprised shortcomings 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 proportionate to the safety implications. Since these new internal baseline requirements have been applied, ASN finds that in most situations, EDF corrects the deviations within the required time. 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 2023 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 2024 and will in this respect continue its inspections of the condition of equipment and systems. 2.6 PREVENTION AND MANAGEMENT OF ENVIRONMENTAL AND HEALTH IMPACTS AND NON-RADIOLOGICAL RISKS 2.6.1 Discharges, waste management and health impacts Limiting water intake and environmental discharges NPPs discharge liquid and gaseous effluents. The origin of these effluents, which can be radioactive or chemical, is the actual operation of the reactor, primarily the operations designed to ensure the radiochemical quality of the main primary 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 chosen by the licensee and taking into consideration the characteristics of the installation, its location and the local environmental conditions. It verifies that these limits have acceptable environmental and health impacts. 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 operating experience feedback 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. In 2023, ASN updated the resolutions regulating the conditions of water intake, consumption, discharge into the environment, and the effluent discharge limits for the Blayais and Tricastin NPPs. Finally, every year, the licensee of each NPP sends ASN an annual environmental report which notably contains a summary of the intakes from and discharges into the environment, any impacts they may have, and any significant events which have occurred. The impact of thermal discharges from the NPPs NPPs discharge hot liquid effluents into watercourses or the sea, either directly, from those NPPs operating with “once-through” cooling, or after cooling of these effluents in cooling towers, enabling some of the heat to be dissipated to the atmosphere. These thermal discharges lead to a temperature rise in the natural environment between the points upstream and downstream of the discharge which, depending on the reactors, can range from a few tenths of a degree to several degrees. These thermal discharges are regulated by ASN resolutions specific to each NPP. ASN Report on the state of nuclear safety and radiation protection in France in 2023 307 • 10 • The EDF Nuclear Power Plants 10 05 15 08 11 04 14 06 07 13 AP 03 02 09 12 01
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