The operational safety of nuclear facilities is taken into consideration from the initial design stage, and is regularly monitored, together with the implementation of an employee motivation policy and large-scale investment programmes.
Discrepancies that are particularly important according to the criteria defined by the ASN are referred to as “specific events”. The detection of significant events by nuclear operators plays a key role in the prevention of incidents and accidents. The regulations require all nuclear operators to declare significant events to the ASN for the protection of the interests mentioned in Article L. 593-1 of the French Environment Code. Each event is analysed by the plant’s teams to determine whether it is significant, and the independent safety reviewer also provides an independent assessment.
Those events that concern safety are known as “SSEs”. This declaration process is part of the ongoing drive to improve nuclear safety and radiation protection and transparency. Its aim is, in particular, to enable the analysis of these events, so as to facilitate subsequent assessment of an incident or the risk of an incident, and to improve the practices of an establishment and/or of a sector of activity in the field of prevention.
Nuclear operators and transporters of nuclear material must declare all significant events to the ASN, at the latest within 48 business hours, along with the proposed classification using the INES (1) scale (a scale of one to seven, with seven being themes serious; incidents without nuclear safety significance are declared as“Level 0”). The ASN is ultimately responsible for the final classification decision. The use of the INES scale enables the ASN to select among all the significant events that occur, those of sufficient importance to be communicated by it.
Since the establishment of a scale of this kind in France in 1987, no INES scale level 3 events (serious incident – very low external emission, and exposure of the public representing a fraction of regulatory limits) or above has occurred in the French nuclear fleet. In 2021, EDF declared 752 significant safety events (SSEs) in France, an improvement on the 745 SSEs declared in 2020. No INES scale level 2 SSE (compared to 1 in 2020) and 79 INES scale level 1 SSEs (compared to 91 in 2020) were declared.
Moreover, the Group’s nuclear safety policy is an integral part of the training courses that the employees of EDF and of its service providers are required to take. After initial training that lasts for several months, and even up to 24 months for key positions (Safety Engineers, Operators, etc.), each employee has to take mandatory annual, biannual and triannual refresher courses depending on the business line and field.
The 2021 detailed results on nuclear safety are published in the annual report created by the General Inspector for Nuclear Safety and are available on the Internet (2).
The mobilisation of various players has permitted a continuous improvement in dose levels (cleanliness of facilities, compliance with time/distance guidelines, improved materials, optimised installation of lead screens, etc.). Thus, the average annual collective dose of all workers, both employees of EDF and outside companies intervening in power plants, has been halved in less than ten years. In 2021, the average collective dose was 0.71 man-sievert per reactor. The average individual does (EDF and contractors) remained below 1mSv (0.96mSv). The hourly does remain stable throughout the year and was the second lowest achieved for the fleet, with 5.8μSv per hour worked in controlled areas.
EDF is proactively implementing an ALARA (As Low as Reasonably Achievable) policy to limit the collective does in parallel with an increasing workload involved in the industrial project on the fleet in operation. EDF is, furthermore, committed to continuing to lower exposure to radiation below the regulatory limit of 20mSv over 12 rolling months for the whole body. Accordingly, throughout 2021 and over 12 rolling months, no participant (among the EDF employees and contractors) was exposed to an individual dose of higher than 14mSv.
In the coming years, given the levels already achieved, efforts will focus on cleaning power plant circuits.
In France, nuclear activities that present a risk of exposing persons to ionising radiation are regulated by two separate sets of rules, depending on the category of persons to be protected.
Regulations on the basic protection of the population against such radiation, which are governed by the French Public Health Code, are primarily based on all nuclear activities being subject to a declaration, registration or authorisation. The authorisations granted to establish a Basic Nuclear Facility serve as the authorisation required under the French Public Health Code.Article R. 1333-11 of the French Public Health Code sets the maximum exposure level of the general public at 1 mSv per year.
French regulations on the protection of workers against the dangers of ionising radiation, which are governed by the French Labour Code, lay down various obligations for employers of workers who are likely to be exposed.
The risks related to nuclear fuel cycle are described in chapter 2 risk 5D "Control of the fuel cycle".
The nuclear fuel cycle encompasses all industrial operations in France and abroad which enable the supply of fuel to generate energy in a reactor, then to unload and process it.
The cycle can be broken down into three stages:
EDF coordinates all the operations in the fuel cycle. Generally speaking, upstream and downstream operations are carried out by subcontractors or suppliers, generally on the basis of multi-year contracts. EDF acquires most of the raw materials as uranium concentrates (U3O8), with transformation into more processed products carried out by industrial operators through service contracts (fluorination, enrichment and production). EDF provides core cycle operations. EDF is the owner in most cases and is responsible for the fuel and materials it uses throughout all different stages of the cycle.
(1) International Nuclear Event Scale.
(2) For example for the 2020 report: https://www.edf.fr/sites/default/files/contrib/groupe-edf/producteur-industriel/nucleaire/notes%20d %27information/rapport-2020-fr-v08b-web.pdf
