ASN Report 2018

• The long-term behaviour of the sites Redevelopment of the uranium processing tailings disposal sites was made possible by 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 studies submitted for the PNGMDR 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 mining waste rock piles and the mining waste rock in the public domain in relation to the results obtained in the 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. In accordance with ASN opinion 2016-AV-0255 of 9 February 2016, these various studies are continuing under the PNGMDR 2016-2018, as is the work of the two technical working groups focusing on: ∙ ∙ maintaining the functions of the structures surrounding the uranium ore treatment residue disposal areas; ∙ ∙ management of the water from the former uranium mining sites. Thus, in January 2017, Orano Mining supplemented its study on the relation between the discharged flows and the accumulation of marked sediments in the rivers and lakes. This study is currently being examined by ASN. In January and June 2018, two interim reports concerning the reactivity of the mine tailings and mining waste rocks respectively were submitted by Orano Mining. The interim assessment of the management of stations treating the water from the former uranium-bearing sites received in January 2018  will be analysed by the PNGMDR technical working group dedicated to water management. • Management of reused mining waste rock Most of the mining waste rock has remained on the site where it was produced (mine in-fill, redevelopment work or spoil heaps). Nonetheless, 1 to 2% of the mining waste rock may have been used as backfill, in earthworks or for road beds in public places situated near the mining sites. Although the reuse of waste rock in the public domain has been traced since 1984, knowledge of reuses prior to 1984 remains incomplete. ASN and the Ministry responsible for the Environment, in the framework of the action plan drawn up further to the Circular of 22 July 2009, asked Orano Mining to inventory the mining waste rock reused in the public domain in order to verify compatibility of the uses and to reduce the impacts if necessary. Orano Mining has thus deployed a plan of action comprising three broad phases: ∙ ∙ aerial overflight around the former French mining sites to identify radiological singularities; ∙ ∙ inspection on the ground of areas identified in the overflight to confirm the presence of waste rock; ∙ ∙ treatment of areas of interest incompatible with the land usage. The second phase of this action plan was completed in 2014. The Ministry responsible for the Environment defined the procedures for managing cases of confirmed presence of mining waste rock in an Instruction to Prefects of 8 August 2013. Some work has been carried out since 2015 on sites classified as priorities, that is to say sites where the calculation of the added annual effective dose excluding radon due to the presence of waste rock on generic scenarios exceeds the value of 0.6 millisieverts per year (mSv/year) on the basis of a radiological impact study. Within the framework of the PNGMDR 2016-2018, an assessment of the actions taken to inventory mining waste rock in the public domain was submitted by Orano in January 2018 and will be examined by ASN in 2019. All these operations are under the administrative surveillance of the Prefect, on the basis of proposals from the Regional Directorate for the Environment, Planning and Housing (Dreal). ASN assists the Prefects with regard to the radiation protection of workers and the public and the review of the management routes. In this context it encourages the complete clean-out of the sites when this is technically possible and asks that any other procedure implemented be justified with regard to this reference strategy. Furthermore, the Dreal is particularly attentive to cases that could lead to human exposure, especially to radon. Lastly, it ensures that the actions are carried out with complete transparency, by involving the local players as much as possible, and that the information relating to these actions is preserved so that the future use of these sites can be managed. The ASN regional divisions participate in the former uranium mining site monitoring commissions which comprise representatives of the State, local authorities, environmental protection associations and Orano Mining. ASN report on the state of nuclear safety and radiation protection in France in 2018  371 14 – RADIOACTIVE WASTE AND CONTAMINATED SITES AND SOILS 14