ASN Report 2020

3.3.2 The radiation protection situation The use of particle accelerators presents significant radiation exposure risks for the workers; ASN is particularly attentive to these facilities and therefore inspects them regularly. In 2018, ASN put in place inspection indicators specific to particle accelerators, which now enable the radiation protection situation in this sector of activity to be better assessed on the national scale. Between 2018 and 2020, 38 facilities equipped with these devices were inspected by ASN, 12 of them in 2020. ASN considers the radiation protection situation in the facilities using these devices to be satisfactory on the whole. In effect, the key requirements for conducting this activity with a satisfactory level of radiation protection (organisation of radiation protection, informing and training, technical verifications and design of the premises in which these devices are used) are appropriately implemented by the large majority of the licensees. Nevertheless, these inspections have also identified areas for improvement on which ASN will remain vigilant: ∙ compliance with the regulations dictating the frequency of technical verifications of work equipment (which under current regulations are carried out by ASN-approved bodies) and the formalised processing of any nonconformities detected during these checks; ∙ the presence of an unlocking device which can be actuated from inside the rooms in which particle accelerators are used; ∙ the correct functioning of the audio signal associated with the patrol procedure, which aims to confirm that nobody is in the room before authorising the emission of ionising radiation; ∙ the availability of radioactivity measurement devices in sufficient quantities for the operators who access these rooms. Lastly, with regard to experience feedback, no significant radiation protection event was reported to ASN in 2020, apart from the recurrent events associated with the use of particle accelerators in shipment security checks. When conducting these checks, the customs services take precautions (such as broadcasting information messages in several languages) to avoid the unjustified irradiation of people who could be hiding in these vehicles (see point 3.3.1). However, despite these precautions, the customs services regularly notify ASN of events relating to the exposure of people hidden in checked vehicles. Although this exposure is unjustified, it nevertheless remains extremely low with effective doses of just a few microsieverts per person. 3.4  Research activities involving unsealed radioactive sources 3.4.1 The devices used In the research sector, as at 31 December 2020, ASN counted 657 licenses issued under the Public Health Code, of which nearly 90% are issued to public or mixed (public/private) entities. The number of licenses has been decreasing constantly for five years, since about 10 licenses on average are repealed each year. This reduction can essentially be explained by two factors: either the replacement of sources of ionising Synchrotrons The synchrotron is a member of the same circular particle accelerator family as the cyclotron (see point 4-2), but is far larger, enabling energies of several gigaelectronvolts to be achieved by means of successive accelerations. Owing to the low mass of the particles (generally electrons) the acceleration created by the curvature of their trajectory in a storage ring, produces an electromagnetic wave when the speeds achieved become relativistic: this is synchrotron radiation. This radiation is collected at various locations called beam lines and is used to conduct scientific experiments. ASN Report on the state of nuclear safety and radiation protection in France in 2020 259 08 – SOURCES OF IONISING RADIATION AND THEIR INDUSTRIAL, VETERINARY AND RESEARCH APPLICATIONS 08 GRAPH 10 Distribution of particle accelerators by end-purpose 2 2 0 5 10 15 20 25 Number of licensees 1 3 3 3 3 4 4 5 11 23 Neutron analysis Other Surface treatment (including polymer cross-linking) Measuring instrument calibration Veterinary radiotherapy Ion implantation Sterilisation Logging Security inspection Design of accelerators for commercialisation Non-destructive inspection Scientific research