3.2 Doses received by the population 3.2.1 Exposure of the population as a result of nuclear activities The automated monitoring networks managed nationwide by IRSN (Téléray, Hydrotéléray and Téléhydro networks) offer real-time monitoring of environmental radioactivity and can highlight any abnormal variation. In the case of an accident or incident leading to the release of radioactive substances, these measurement networks would play an essential role by providing data to inform the decisions to be taken by the authorities and to inform the population. In normal situations, they contribute to the evaluation of the impact of BNIs (see chapter 3). On the other hand, there is no overall monitoring system able to provide an exhaustive picture of the doses received by the population as a result of nuclear activities. Consequently, compliance with the population exposure limit (effective dose set at 1 mSv/year) cannot be controlled directly. However, for BNIs, there is detailed accounting of radioactive effluent discharges and radiological monitoring of the environment is implemented around the installations. On the basis of the data collected, the dosimetric impact of these discharges on the populations in the immediate vicinity of the installations is then calculated using models simulating transfers to the environment. The dosimetric impacts vary, according to the type of installation and the lifestyles of the chosen representative persons, from a few microsieverts to several tens of microsieverts per year (μSv/year). An estimation of the doses from BNIs is presented in Table 4 which shows, for each site and per year, the estimated effective doses received by the most exposed representative persons. There are no known estimates for nuclear activities other than BNIs owing to the methodological difficulties involved in identifying the impact of these facilities and in particular the impact of discharges containing small quantities of artificial radionuclides resulting from the use of unsealed radioactive sources in research or biology laboratories, or in nuclear medicine units. To give an example, the impact of hospital discharges could lead to doses of a several tens of microsieverts per year for the most exposed persons, particularly for certain jobs in sewage networks and wastewater treatment plants (IRSN studies 2005 and 2015). Legacy situations, such as atmospheric nuclear tests and the Chernobyl accident (Ukraine), can make a marginal contribution to population exposure. Thus, the exposure due to fall-out from nuclear tests is currently estimated at 2.3 μSv/year in metropolitan France (1.3 µSv/year for strontium-90 and 1 μSv/year for carbon-14; exposure linked to caesium-137 cannot be distinguished from that due to fall-out from the Chernobyl accident). The overall exposure due to fall-out from nuclear tests and the Chernobyl accident is 46 μSv/year for people living in areas of high persistence of this fall-out and 9.3 μSv/year for people over the rest of the country, that is to say an average dose per inhabitant of 12 μSv/year for the country as a whole (IRSN 2021). With regard to the fall-out in France from the Fukushima Daiichi NPP accident (Japan), the results published for France by IRSN in 2011 showed the presence of radioactive iodine at very low levels, resulting in estimated effective doses for the populations of less than 2 μSv/year in 2011. TABLE 3 Development of number of persons monitored and average collective and individual doses in the exposed population from 2015 to 2023(*) in all areas combined (A) and in the “natural” area (B) Year Number of persons monitored Collective dose (man-Sv) Average individual dose (mSv) (A) (B) (A) (B) (A) (B) 2015 (*) 372,881 352,641 104.41 65.61 0.98 0.76 2016 (*) 378,304 357,527 107.53 66.71 0.96 0.73 2017 384,198 360,694 100.58 53.52 1.03 0.72 2018 390,363 365,980 104.14 55.24 1.12 0.80 2019 395,040 369,712 112.31 58.73 1.20 0.85 2020 387,452 364,614 72.43 49.97 0.78 0.71 2021 392,180 370,756 82.71 60.09 0.85 0.78 2022 386,080 363,595 88.43 59.01 0.90 0.77 2023 360,743 337,706 84.23 58.05 0.95 0.87 * For comparison purposes, the results for 2015 and 2016 have been retroactively reassessed applying the new methodological approach. (Source: Worker radiation protection: occupational exposure to ionising radiation in France – IRSN 2023 report, June 2024) TABLE 2 Monitoring of external exposure of workers in small-scale nuclear activities (year 2023) Number of persons monitored Collective dose (man-Sv(*)) Individual dose > 20 mSv Medicine 149,950 6.76 2 (1) Dental 37,819 1.13 2 (2) Veterinary 23,315 0.25 0 Industry 14,519 3.39 1 (3) Research and education 9,429 0.20 0 Natural (**) 23,137 26.2 0 Total small-scale nuclear activities 258,169 37.9 5 (1) These cases were retained by default as the occupational physician gave no feedback on the conclusions of the investigation. (2) These cases were retained by default as the occupational physician gave no feedback. (3) These cases were retained by default as the occupational physician gave no feedback. * Man-Sv: unit of quantity of collective dose. ** “Natural” covers flight crew and workers exposed to natural radionuclides of the uranium and thorium decay chains. (Source: Worker radiation protection: occupational exposure to ionising radiation in France – IRSN report 2023) TABLE 1 Monitoring of external exposure of workers in the civil nuclear field (year 2023) Number of persons monitored Collective dose (man-Sv(*)) Individual dose > 20 mSv Reactors and energy production (EDF) 24,552 6.54 0 “Fuel cycle”; decommissioning 12,579 4.07 0 Transport 442 0.06 0 Logistics and maintenance (contractors) 34,106 32.24 0 Effluents, waste 729 0.15 0 Others 7,823 1.28 1 Total civil nuclear 80,231 44.34 1 * Man-Sv: unit of quantity of collective dose. For information, the collective dose is the sum of the individual doses received by a given group of persons. (Source: Worker radiation protection: occupational exposure to ionising radiation in France – IRSN report 2023) 110 ASN Report on the state of nuclear safety and radiation protection in France in 2024 Nuclear activities: ionising radiation and health and environmental risks
RkJQdWJsaXNoZXIy NjQ0NzU=