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 due to industrial process deposits (scale forming in piping for example). In 2022, the individual monitoring of worker exposure in industrial activities leading to exposure to substances of natural origin or to radon of geological origin (exposure to natural radionuclides of the uranium and thorium decay chains) concerned 667 workers monitored for external exposure (including 39 workers exposed to more than 1 mSv) and 311 workers monitored for internal exposure (of whom 18 were exposed to more than 1 mSv). Flight crew exposure to cosmic radiation Airline flight crews and certain frequent flyers are exposed to significant doses owing to the altitude and the intensity of cosmic radiation at high altitude. These doses can exceed 1 mSv/year. Since 1 July 2014, IRSN calculates the individual doses for civil flight personnel using the SievertPN application, on the basis of the flight and personnel presence data provided by the airlines. These data are subsequently transmitted to Siseri, the French national worker dosimetry registry. As at 31 December 2022, SievertPN had transmitted to Siseri all the flight crew doses for 14 airlines having subscribed to the system, giving a total of 21,162 flight crew members monitored by this system. In 2022, nearly 33% of the individual annual doses were below 1 mSv and 66% of the individual annual doses were between 1 mSv and 5 mSv. The maximum individual annual dose was 3.68 mSv. In 2022, the collective dose was 29.5% higher than in 2021. This increase can be explained by the recovery of air traffic in 2022 after the improvement in the health situation following the Covid-19 pandemic. 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. DIAGRAM Average exposure using the dose coefficient in effect prior to 1 January 2024 1B DIAGRAM Average exposure using the dose coefficient currently in effect 1A Source: IRSN, 2021. 0.01 Others (discharges from facilities, fallout from atmospheric tests) 0.6 Terrestrial radiation 1.5 Medical 3.5 Radon TOTAL 6.5 mSv/year 0.6 Water and foodstuffs 0.3 Cosmic radiation 0.01 Others (discharges from facilities, fallout from atmospheric tests) 0.6 Terrestrial radiation 1.5 Medical 1.5 Radon TOTAL 4.5 mSv/year 0.6 Water and foodstuffs 0.3 Cosmic radiation Source: IRSN, 2021. 108 ASN Report on the state of nuclear safety and radiation protection in France in 2023 • 01 • Nuclear activities: ionising radiation and health and environmental risks
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