ASN Report 2020

Finally, ASN observes that certain systems linked to the “support”, “reactivity control” and “cooling” safety functions are subject to recurring unscheduled unavailability. This is notably the case with the reactor component cooling systems, post-accident monitoring, reactor nuclear power measurement and SG back-up feedwater supply. These unavailabilities will require an analysis and discussions with EDF in 2021 in order to identify any improvements needed. Notification of significant events by EDF Pursuant to the rules for the notification of significant events (see chapter 3, point 3.3), ASN received 740 Significant Safety Event (ESS) reports from EDF in 2020, along with 174 Significant Radiation Protection Event (ESR) reports and 61 Significant Environmental Protection Event (ESE) reports. The number of significant events fell by about 2.4% in 2020 by comparison with the previous year. This drop is the result of a significant fall in the number of ESE (83 ESEs in 2019). Graph 1 shows the trend since 2010 in the number of significant events notified by EDF and rated on the INES scale. Graph 2 shows the trend since 2010 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. Twenty-six events of this type were reported in 2020 in the field of nuclear safety. Reactor outages The reactor outages schedule for 2020 was extensively disrupted by the health crisis. The travel restrictions put in place by the Government in the spring of 2020 at first severely reduced EDF’s ability to carry out scheduled maintenance work during the reactor refuelling outages. EDF decided to prolong the theoretical durations of all the scheduled outages and to postpone or cancel some of them. ASN made sure that the maintenance and outage operations were pushed back by EDF in compliance with the applicable safety rules. The conditions in which EDF carried out its activities were made more complicated by the implementation of barrier measures to prevent the spread of the disease. 2.5  Prevention and management of environmental and health impacts 2.5.1 Monitoring of discharges and of waste management Monitoring the management of water intake and environmental discharges The Environment Code gives ASN competence to issue binding requirements regarding BNI water intake and effluent discharges (see chapter 3, point 4.1). The laws and regulatory texts for protection of the environment that apply to French NPPs comprise generic texts, mainly the Environment Code, the Order of 7 February 2012 and ASN resolutions 2013-DC-0361 of 16 July 2012 relating to control of the detrimental effects and health and environment impacts of BNIs, and 2017-DC-0588 of 6 April 2017, concerning the methods of water intake and consumption, effluent discharges and environmental monitoring of PWRs, as well as regulatory texts specific to each of the NPPs: ∙ decisions setting the procedures for water intake and consump­ tion and environmental discharges of liquid and gaseous effluents (chemical and radioactive); ∙ decisions setting the environmental discharge limits for liquid and gaseous effluents (chemical and radioactive); these decisions are approved by the Minister responsible for nuclear safety; ∙ the Orders of the Prefect authorising water intake and discharges of liquid and gaseous effluents: pre-dating November 2006, they contain binding requirements concerning the discharge procedures and limits specific to a nuclear site. In order to apply the new regulatory architecture to all the French NPP reactors, revision of the orders has led to them being repealed, with the adoption of ASN resolutions. For each site, ASN sets the limit values for emissions, 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 control of detrimental effects and the impact of PWRs on health and the environment. 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. Finally, every year, the NPP licensees send ASN an annual environmental report which notably contains a summary of the intakes from and discharges into the environment, any impacts they may have, the significant events which have occurred and the future outlook. The impact of thermal discharges from the Nuclear Power Plants NPPs discharge hot 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. Thermal discharges from NPPs lead to a temperature rise 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. Since 2006, provisions have been incorporated into these resolutions for advance definition of the operations of NPPs in exceptional climatic conditions leading to significant warming of the watercourse. These special provisions are however only applicable if the security of the electricity grid is at stake. Monitoring of waste management The management of the conventional and radioactive waste produced by the NPPs falls within the general framework of BNI waste management. The legal framework for the management of waste applicable to the NPPs comprises legislative and regulatory texts of general scope, notably the Environment Code, the Order of 7 February 2012 and ASN resolution 2015-DC-0508 of 21 April 2015 concerning the study of waste management and the inventory of waste produced in BNIs. In compliance with the Environment Code, EDF carries out waste sorting at source, differentiating in particular between waste from nuclear zones and other waste. For all the waste, ASN examines the study produced by the licensee regarding waste management. This document is specific to each facility, as required by the regulations (see “Regulation” heading on asn.fr ). This document more specifically presents a description of the operations which are the cause of production of the waste, the characteristics of the waste produced or to be produced, an estimation of the waste traffic volumes and a waste zoning plan. ASN Report on the state of nuclear safety and radiation protection in France in 2020 303 10 – THE EDF NUCLEAR POWER PLANTS 10