ASN Report 2022

Table 3 shows that the total number of workers monitored by passive dosimetry increased by 5% between 2015 and 2021, all areas combined. At the same time, the collective dose fell by 20% over the same period to reach 82.71 man-Sv(9) in 2021. The average individual dose thus decreased from 0.98 mSv in 2015 to 0.85 mSv in 2021. The increase in the collective dose and the average individual dose for all areas combined between 2020 and 2021 (+14% and +9% respectively) can be explained mainly by the increase in the volume of maintenance work in the nuclear sector due to the improvement in sanitary conditions linked to the Covid-19 pandemic. For these same reasons, the average annual individual dose, which was 0.85 mSv in 2021, is 9% higher than that observed in 2020. In 2021, one case of exceeding the regulatory whole body effective dose limit of 20 mSv was recorded in the medical field (diagnostic radiology sector). The exceedance (external exposure of 25.8 mSv over 12 sliding months) was detected during 2021 and corresponded to the accumulation of several doses between June 2020 and May 2021. It should nevertheless be noted that this case was retained by default, as the occupational physician gave no feedback on the conclusions of the investigation. A case of exceeding the regulatory equivalent dose limit to the skin of 500 mSv was recorded in the civil nuclear sector (in the energy production power reactors sector) with an equivalent dose of 818 mSv. This equivalent dose, associated with the deposition of a radioactive fragment on the body of a worker, was estimated very conservatively given that it was impossible to determine with precision when this fragment was deposited on the worker. With regard to the dosimetry of the extremities (fingers and wrists), 28,335 workers were monitored in 2021 (i.e. 7% of the total number of persons monitored). For the first time since 2013, no exceedance of the regulatory limit for the equivalent dose to the extremities of 500 mSv was recorded in 2021. With regard to dosimetric monitoring of the lens of the eye, it has been increasing since 2015. It concerned 5,970 workers in 2021. 9. Man-Sv: unit of quantity of collective dose. 10. In the transitional period from July 2018 – June 2023, the occupational exposure limit for the equivalent dose to the lens of the eye is 50 mSv over 12 months (with a ceiling at 100 mSv over 5 years). As from July 2023, this exposure limit value will be 20 mSv over 12 months. A worker in the nuclear medicine sector received a dose exceeding 50 mSv in 2021 (138.1 mSv) which, for the transitional period from July 2018 to June 2023 provided for by the regulations, constitutes an exceedance of the occupational exposure limit(10). Furthermore, four workers (in diagnostic radiology and interventional radiology) received an equivalent dose to the lens of the eye of between 20 mSv and 50 mSv, without the five-year accumulated dose exceeding 100 mSv. The maximum recorded dose is 27.9 mSv. This value should be compared with the future regulatory dose limit for the lens of the eye of 20 mSv/year as from 2023. To conclude, as in the preceding years, the assessment of monitoring of workers exposed to ionising radiation in France in 2021 published by IRSN in June 2022, shows the overall effectiveness of the prevention system introduced in facilities where sources of ionising radiation are used, because for nearly 94% of the population monitored, the annual dose remained below 1 mSv (effective annual dose limit for the public due to nuclear activities). The last ten years have witnessed a regular reduction in the number of most heavily exposed workers. Cases of exceeding the regulatory limit values remain exceptional (one exceedance of the annual limit of 20 mSv, one exceedance of the equivalent dose to the skin of 500 mSv and one exceedance of the equivalent dose to the lens of the eye of 50 mSv). Monitoring of exposure of the lens of the eye with, for this tissue, compliance with the new limit, constitutes the main objective of radiation protection in the immediate years and more specifically in the area of FGIPs. 3.1.2 Case of worker exposure to natural radioactivity Exposure to radioactive substances of natural origin and to radon of geological origin Worker exposure to radioactive substances of natural origin results either from the ingestion of dust from materials containing large amounts of radionuclides (phosphates, metal ores), or from the inhalation of radon formed by uranium decay (poorly ventilated warehouses, thermal baths) or from external exposure SOURCES AND ROUTES OF EXPOSURE TO IONISING RADIATION Inhalation External radiation Skin contamination External radiation Internal contamination by inhalation of radioactive substances Skin contamination Ingestion External radiation Skin contamination and involuntary ingestion External radiation Internal contamination through ingestion of contaminated foodstuffs Skin contamination and involuntary ingestion 108 ASN Report on the state of nuclear safety and radiation protection in France in 2022 • 01 • Nuclear activities: ionising radiation and health and environmental risks 01