For discharges of chemical substances with an emission limit value set by an ASN binding requirement, when the concentration values measured are below the quantification limit, the licensee is required by convention to declare a value equal to half the quantification limit concerned. Per- and polyfluoroalkyl substances Per- et Polyfluoroalkyl Substances (PFAS) are substances which degrade very slowly and are highly persistent in the environment, which poses many questions regarding their toxicity, both for human health and for the environment. Following the action plan initiated by the Government in January 2023 to reduce PFAS-related hazards and improve the awareness of the population regarding exposure to these substances, ASN asked the BNI licensees whose activities are liable to be the cause of PFAS emissions to draw up a list of the PFAS used, produced, processed or discharged by their facility and then to carry out a campaign to search for and quantify their presence in the aqueous discharges from their facility. Although the industrial processes employed in the BNIs do not use any PFAS, certain equipment (seals, mechanical packings, fire-fighting foam) present in the BNIs is liable to contain them. In 2024, the licensees of the BNIs concerned therefore carried out measurement campaigns, first of all on samples taken from the non-radioactive liquid discharge networks in their installations. These initial results confirm the absence of PFAS in the discharges in the majority of cases. Some facilities undertook to supplement their campaign by one or more measurements when the occasional presence of PFAS was detected. The results of additional campaigns to be performed on radio- active discharges are also expected by the end of 2026. Following these campaigns, and if PFAS are confirmed as being present in BNI discharges, ASN could issue prescriptive requirements to regulate these discharges by setting emission limits and appropriate monitoring procedures. Monitoring of discharges in the field of small-scale nuclear activities Pursuant to ASN resolution 2008-DC-0095 of 29 January 2008, radioactivity measurements are taken on the effluents coming from the facilities that produce them. In hospitals that have a nuclear medicine department, these measurements chiefly concern iodine-131 and technetium-99m (see chapter 7). In the small-scale industrial nuclear sector, few facilities discharge radioactive effluents apart from cyclotrons (see chapter 8). The discharge permits stipulate requirements for the discharges and their monitoring, which are subject to particular scrutiny during inspections. For nuclear medicine units and research laboratories, IRSN proposes a graded approach to monitoring of radioactive discharges into the public sewer system. This approach could consist of sampling and measurement protocols, as well as guideline levels to be compared with the results of these measurements in order to decide whether any corrective measures are needed. 4.1.2 Evaluating the radiological impact of nuclear activities The radiological impact of effluents produced by medical activities and small-scale nuclear activities The impact of radioactive discharges on sanitation workers (sewerage workers and wastewater treatment plant workers) and on workers responsible for removing and spreading wastewater treatment sludge can, since 2019, be evaluated using the CIDRRE tool (Calculation of impact of radioactive discharges into the networks), developed by IRSN. The final result is a prudent over-estimation, which gives an approximate idea of the doses liable to be received per category of sanitation workers, according to the facility which carries out the discharge, the collection system receiving it and the plant which treats the wastewater. CIDRRE is a means of ensuring that the annual dose received by the sanitation workers remains below 1 millisievert (mSv). For the population, the estimated radiological impact linked to radioactive discharges from nuclear medicine units and research laboratories into the sewerage systems would appear to be below 300 microsieverts per year (μSv/year) in all the studies, even in worst-case scenarios considering all the radionuclides detected in the sanitation systems. This impact is estimated to be lower than 1 μSv/year when the radionuclides used in nuclear medicine are not taken into account, with realistic hypotheses (IRSN data). The radiological impact of BNIs In accordance with the optimisation principle, the licensee must reduce the radiological impact of its facility to values that are as low as possible under economically acceptable conditions. The licensee is required to assess the dosi- metric impact of its activity. As applicable, this obligation is the result of Article L. 1333-8 of the Public Health Code, or the regulations concerning BNI discharges (Article 5.3.2 of amended ASN resolution 2013- DC-0360 of 16 July 2013 concerning control of detrimental effects and the impact of BNIs on health and the environment). The result is to be assessed considering the allowable annual dose limit for the public (1 millisievert per year – mSv/year) defined in Article R. 1333-11 of the Public Health Code, which corresponds to the sum of effective doses received by the public as a result of nuclear activities. In practice, only traces of artificial radio- activity are detectable in the vicinity of the nuclear facilities; most measurements taken during routine surveillance are below the decision threshold or reflect the natural radioactivity. As these measurements cannot be used for dose estimations, models for the transfer of radioactivity to humans must be used, on the basis of measurements of discharges from the installation. These models are specific to each licensee and are detailed in the facility’s impact assessment. During its assessment, ASN devotes efforts to verifying that these models are conservative, in order to ensure that the impact assessments are not underestimated. Wiith regard to measurements • The Decision Threshold (SD) is the value above which it is possible with a high degree of confidence to conclude that a radionuclide is present in the sample. • The Detection Limit (LD) is the value as of which the measurement technique is able to quantify a radionuclide with a reasonable degree of uncertainty (the uncertainty is about 50% at the LD). More simply, LD ≈ 2 x SD. For the measurement results on chemical substances, the Quantification Limit is equivalent to the Detection Limit used to measure radioactivity. Reference spectra For the NPPs, the reference spectra of discharges comprise the following radionuclides: • Liquid discharges: tritium, carbon-14, iodine-131, other fission and activation products (manganese-54, cobalt-58, cobalt-60, nickel-63, silver-110m, tellurium-123m, antimony-124, antimony-125, caesium-134, caesium-137); • Gaseous discharges: tritium, carbon-14, iodines (iodine-131, iodine-133), other fission and activation products (cobalt-58, cobalt-60, caesium-134, caesium-137), noble gases: xenon-133 (permanent discharges from ventilation networks, when draining “RS” effluent storage tanks and at decompression of reactor buildings), xenon-135 (permanent discharges from ventilation networks and at decompression of reactor buildings), xenon-131m (when draining “RS” tanks), krypton-85 (when draining “RS” tanks), argon-41 (at decompression of reactor buildings). ASN Report on the state of nuclear safety and radiation protection in France in 2024 161 01 Regulation of nuclear activities and exposure to ionising radiation 03 05 06 07 08 09 10 11 12 13 14 15 AP 02 04
RkJQdWJsaXNoZXIy NjQ0NzU=