the scope of the inspection is then broadened to cover all of the above-mentioned topics. Within this context, situational exercises can be carried out to test the organisation implemented for pollution management (see chapter 10). Accounting of BNI discharges The rules for accounting of discharges, both radioactive and chemical, are set in the general regulations by amended ASN resolution 2013-DC-0360 of 16 July 2013 relative to control of the detrimental effects and the impact of BNIs on health and the environment. These rules were set so as to guarantee that the discharge values declared by the licensees, notably those considered in the impact calculations, will in no case be under-estimated. For discharges of radioactive substances, accounting is not based on overall measurements, but on an analysis per radionuclide, introducing the notion of a “reference spectrum”, listing the radionuclides specific to the type of discharge in question. The principles underlying the accounting rules are as follows: ∙ radionuclides for which the measured activity exceeds the decision threshold for the measurement technique are all counted; ∙ the radionuclides of the “reference spectrum” for which the measured activity is below the decision threshold (see box opposite) are considered to be at the decision threshold level. 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. The results of these measurement campaigns are expected for the end of 2024 and could, if PFAS are confirmed as being present in BNI discharges, lead ASN to issue binding 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 places 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). • 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, iodine (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). WITH REGARD TO MEASUREMENTS ASN Report on the state of nuclear safety and radiation protection in France in 2023 159 • 03 • Regulation of nuclear activities and exposure to ionising radiation 03 05 15 08 11 04 14 06 07 13 AP 10 02 09 12 01
RkJQdWJsaXNoZXIy NjQ0NzU=