3 // Monitoring exposure to ionising radiation 6. Exposure of the French population to ionising radiation –Results for 2014-2019, IRSN, 2021. 7. 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. Given the difficulty in attributing a cancer solely to the ionising radiation risk factor, “risk monitoring” to prevent cancers in the population is performed by measuring ambient radioactivity indicators (measurement of dose rates for example), internal contamination or, failing this, by measuring values (activities in radioactive effluent discharges) which can then be used –by modelling and calculation– to estimate the doses received by the exposed populations. The entire population of France is exposed to ionising radiation of natural or anthropogenic origin, but to different extents across the country. The average exposure of the French population is estimated at 4.5 mSv per person per year, but this exposure is subject to wide individual variability, particularly depending on the place of residence (radon potential of the municipality, level of terrestrial radiation), the number of radiological examinations the person undergoes, consumption (smoking, foodstuffs) and living habits (air travel). The average annual individual effective dose can thus vary from 1.6 mSv to 28 mSv(6). Diagram 1 represents an estimate of the respective contributions of the various sources of exposure to ionising radiation for the French population. 3.1 Doses received by workers 3.1.1 Monitoring the exposure of persons working in nuclear facilities The system for monitoring the external exposure of persons liable to be exposed to ionising radiation, working in BNIs or in small-scale nuclear facilities for example, has been in place for several decades. This system is based primarily on the mandatory wearing of passive dosimeters for workers liable to be exposed and enables compliance with the regulatory limits applicable to workers to be checked. These limits concern the total exposure (since 2003, the annual limit expressed in terms of effective dose has been 20 mSv for 12 consecutive months), obtained by adding the dose due to external exposure to that resulting from any internal contamination; other limits, called “equivalent dose limits”, are defined for the external exposure of certain parts of the body such as the hands and the lens of the eye (see “References” heading on asn.fr). The recorded data allow the identification of the cumulative exposure dose for a given period (month or quarter) for each worker, including those from outside contractors. They are grouped together in the Ionizing Radiation Exposure Monitoring Information System (Siseri) managed by IRSN and are published annually. The results of worker exposure to ionising radiation presented below are taken from the IRSN 2020 assessment entitled La radioprotection des travailleurs – exposition professionnelle aux rayonnements ionisants en France (Worker radiation protection –occupational exposure to ionising radiation in France). From the methodological aspect, as in the three preceding years, the IRSN 2020 assessment of external exposure was based exclusively on data from individual monitoring of the external exposure of workers recorded in the Siseri database. Until 2016, the assessments were produced exclusively by aggregating the annual summaries provided by the dosimetry organisations. Consequently, external exposure results for 2020 are not directly comparable with those of 2019, 2018 and 2017. Nevertheless, in order to establish trends, the results for the years 2015 and 2016 have been retroactively reassessed applying the new methodological approach (see Table 3). Tables 1 and 2 present, per area of activity and for the year 2020, the breakdown of the populations monitored, the collective dose (i.e. the sum of the individual doses received by a given group of persons), and the number of times the annual limit of 20 mSv was exceeded. They show a large disparity in the breakdown of doses depending on the sector. For example, the medical and veterinary activities sector, which comprises a significant share of the population monitored (59%), accounts for only 11% of the collective dose; on the other hand, the civil nuclear industry, which represents just 22% of the headcount, accounts for 52% of the collective dose and the sector concerned by exposure to natural radioactivity, which represents only 5.9% of the total headcount, accounts for 31% of the collective dose. The industrial sector, which represents 4.2% of the headcount, accounts for 3.5% of the collective dose. Table 3 shows that the total number of workers monitored by external passive dosimetry increased by about 1% per year from 2015 until 2019. In 2020, the number of workers monitored dropped by 1.9%. The collective dose for 2020 (all sectors combined) is 72.43 man-Sv(7), a value that has fallen by 35.5% compared with 2019 and which has never been as low since 2015. This drop concerns all areas of activity and can be explained primarily by the drop in air traffic resulting in lower exposure of flight crew to cosmic radiation, and spreading of the volume of maintenance work in the nuclear sector, both linked to the consequences of the Covid-19 pandemic. For these same reasons, the average annual individual dose, which was 0.78 mSv in 2020, is 35% lower than that observed in 2019. Five cases of exceeding the effective dose regulatory limit of 20 mSv were recorded in 2020 (see Diagram 2), of which four were related to external exposure and one to internal exposure. The four cases linked to external exposure concern 2 workers in the medical sector, 1 in the veterinary sector and 1 in the nonnuclear industry sector. A fifth case of exceeding the effective dose limit in the medical sector must nevertheless be noted in addition to these four cases, corresponding to a cumulative dose over 12 sliding months from June 2019 to May 2020 and not over the calendar year. Only one case was confirmed by the occupational physician, the others being retained by default in the absence of a response from the occupational physician on the survey conclusions. Exceeding of the regulatory limit of 20 mSv for internal exposure concerns the nuclear domain in the fuel fabrication sector. With regard to the dosimetry of the extremities (fingers and wrist), 27,437 workers were monitored in 2020 (i.e. 7% of the total number of persons monitored). Out of all the persons monitored, there was one case –in the medical sector– where the 500 mSv regulatory equivalent dose limit at the extremities was exceeded (975.8 mSv). Alongside this, 4,429 workers were subject to monitoring of exposure of the lens of the eye (compared with 4,830 in 2019), probably reflecting a drop in activity due to the health crisis, after a strong increase in the preceding years. Four workers (in the medical radiology sector) received an equivalent dose exceeding 20 mSv. The maximum recorded dose is 37.74 mSv. This value ASN Report on the state of nuclear safety and radiation protection in France in 2021 107 01 – NUCLEAR ACTIVITIES: IONISING RADIATION AND HEALTH AND ENVIRONMENTAL RISKS 08 07 13 04 10 06 12 14 03 09 05 11 02 01 AP
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