3. Management of mining residues and mining waste rock from former uranium mines Uranium mines were worked in France between 1948 and 2001, producing 76,000 tons of uranium. Some 250 sites in France were involved in exploration, extraction and processing activities. The sites were spread over 27 départements in the eight regions: Auvergne-Rhône-Alpes, Bourgogne-Franche-Comté, Bretagne, Grand Est, Nouvelle-Aquitaine, Occitanie, Pays de la Loire and Provence-Alpes-Côte d’Azur. Ore processing was carried out in eight plants. The former uranium mines are now almost all under the responsibility of Orano. The working of uranium mines produced two categories of products: ∙ mining waste rock, that is to say the rocks excavated to gain access to the ore. The quantity of mining waste rock extracted is estimated at about 170 million tonnes; ∙ static or dynamic processing tailings, which are the products remaining after extraction of the uranium from the ore. In France, these tailings represent 50 million tonnes spread over 17 disposal sites. These sites are ICPEs and their environmental impact is monitored. Redevelopment of the uranium processing tailings disposal sites consisted notably in placing a solid cover over the tailings to provide a geochemical and radiological protective barrier to limit the risks of intrusion, erosion, dispersion of the stored products and the risks of external and internal exposure of the neighbouring populations. The regulatory context The uranium mines, their annexes and their conditions of closure are covered by the Mining Code. The disposal facilities for radioactive mining tailings are governed by section 1735 of the ICPE classification system. The mines and the mine tailings disposal sites are not subject to ASN oversight. In the specific case of the former uranium mines, an action plan was defined by Circular 2009-132 of 22 July 2009 of the Minister responsible for the environment and the Chairman of ASN, along the following work lines: ∙ monitor the former mining sites; ∙ improve the understanding of the environmental and health impact of the former uranium mines and their monitoring; ∙ manage the mining waste rock (better identify the uses and reduce impacts if necessary); ∙ reinforce information and consultation. PNGMDR: the long-term behaviour of the sites The studies submitted for the PNGMDR since 2003 have enhanced knowledge of: ∙ the dosimetric impact of the mine tailing disposal areas on man and the environment, in particular through the comparison of data obtained from monitoring and the results of modelling; ∙ the evaluation of the long-term dosimetric impact of the waste rock stockpiles and waste rock in the public domain in relation to the results obtained in context of the Circular of 22 July 2009; ∙ the strategy chosen for the changes in the treatment of water collected from former mining sites; ∙ the relation between the discharged flows and the accumulation of marked sediments in the rivers and lakes; ∙ the methodology for assessing the long-term integrity of the embankments surrounding tailings disposal sites; ∙ transport of uranium from the waste rock piles to the environment; ∙ the mechanisms governing the mobility of uranium and radium within uranium-bearing mining tailings. Further to ASN opinion 2016-AV-0255 of 9 February 2016, and in the context of the PNGMDR 2016-2018, Orano submitted 11 studies between January 2017 and February 2020 to supplement the studies submitted prior to this. Based on this, ASN issued an opinion on 4 February 2021 to review the situation on these subjects. Consequently, ASN opinion 2021-AV-0374 of 4 February 2021 specifies the studies still to be carried out to meet the challenges associated with the former mining sites and reiterated above. These studies may lead to the performance of work such as removal of the mining tailings from public land, reinforcement of the structures encircling the disposal sites, and improving preservation of the memory. This opinion also recommends continuing the work of the two technical working groups concerning: ∙ Maintaining the functions of the structures encircling the uranium ore treatment residue disposal areas. The final report on maintaining the functions of the structures encircling the uranium ore treatment residue disposal areas was finalised and published on 30 January 2023. This report must be taken into consideration by Orano in order to update its assessments of the stability of its structures encircling the mining residue disposal sites. ∙ Management of the water from the former uranium mining sites. In 2022, the dedicated technical working group continued development of the multi-criteria multi-player analysis methodology, by testing it on a site, and has also started drawing up a methodological guide. ASN has proposed creating a third working group which will focus on the updating of the methodology for assessing the longterm impact of the mining processing residue disposal sites. This working group will endeavour more specifically to detail the longterm deterioration scenarios for the covers of mining processing residue disposal facilities, in relation with the radioactive waste disposal site development scenarios and the work carried out by the pluralistic expert assessment group for the uranium mining sites of the Limousin region (GEP Limousin). Setting up of the group has been pushed back to 2023, priority having been given to the work of the two working groups mentioned above. The PNGMDR 2022-2026 plans for continuation of these actions concerning the long-term environmental and health impact of the management of the former uranium mines. It will result in the defining of a detailed work programme in 2023. This programme will take into consideration more specifically the updating of the studies on structure stability applying the methodology proposed by the final report on maintaining the functions of the structures encircling the uranium ore treatment residue disposal areas specified above. 374 ASN Report on the state of nuclear safety and radiation protection in France in 2022 • 14 • Radioactive waste and contaminated sites and soils 14
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