ASN issues its opinion on the management of the former uranium mining sites

At the request of the Ministry responsible for energy (MTE), within the framework of the French National Radioactive Material and Waste Management Plan (PNGMDR), and following analysis of the studies received, ASN has issued its opinion on the management of the former uranium mining sites, in order to contribute to the guidelines for the 5th edition of this plan.

The working of the uranium mines in France, between 1948 and 2001, led to the production of 76,000 tonnes of uranium. The exploration, extraction and processing activities concerned about 250 sites in France, which differed considerably in size. All the uranium mining sites have now been rehabilitated ^[1]. A variety of materials or waste are liable to have been disposed of on the former mining sites: mining waste rock, mining tailings and various wastes, notably as a result of the decommissioning of mine-working installations.

The previous editions of the PNGMDR initiated an approach to improve the management of the former uranium mines and the repositories for their tailings, in particular in the light of their long-term environmental and health impacts. For the PNGMDR 2016-2018, the studies submitted by Orano Mining enable this approach to be taken a step further.

The public debate carried out in 2019, in preparation for the production of the 5^th edition of the PNGMDR, underlined the fact that the classification of the uranium mine tailings disposal sites ^[2] as installations classified for protection of the environment (ICPE) and the retrieval of mining waste rock previously disseminated around the public domain, represent a step in the right direction. It however underlined the importance of developing high-quality local dialogue, notably to take account of the long-term impact of these sites.

Evaluation of the long-term dosimetric and environmental impact of uranium mine tailings disposal sites

ASN recalls the need to evaluate the evolution of the long-term dosimetric and environmental impact of the tailings repositories and the corresponding need for a methodology recognised by all the stakeholders.

ASN therefore considers that a specific working sub-group needs to be set up, responsible for updating the long-term evaluation methodology developed by Orano Mining, in conjunction with the work done by the pluralistic expert group on the Limousin uranium mining sites.

ASN also recommends that the working sub-group to deal with maintaining the functions of the structures surrounding the mine tailings repositories should continue its work and finalise the doctrine and methodology for evaluating the long-term resistance of these structures. The working sub-group will involve the interested local actors in its work.

Finally, ASN recommends that Orano Mining complete the modelling of the long-term mobility of uranium and radium-226 within the mine tailings repositories. Following these evaluations, Orano Mining will make proposals to mitigate the long-term impacts of these repositories, if necessary.

Management of water from former uranium mines

ASN recalls the need to have a methodology recognised by all the stakeholders in order to produce a long-term management strategy for the treatment plants for the water from the former mining sites.

ASN considers that the work of the specific sub-group should be continued in order to finalise this “multi-criterion, multi-actor” analysis methodology. ASN recommends that Orano Mining apply it and then produce a long-term management strategy for all the treatment plants for the water from the former uranium mining sites.

In order to minimise any long-term risk of exposure from radiologically contaminated sediments, ASN considers that the processes involved in the build-up of these sediments in rivers or lakes downstream of the uranium mining sites should be identified and specified. For this purpose, ASN recommends that Orano Mining finalise the ongoing study on Saint-Clément lake (Allier département) and then examine whether comparable studies should be carried out on other sites, according to the hydrogeological context or local particularities.

Waste rock survey

ASN observes that the survey of waste rock piles and mining waste rock in the public domain is now completed.

ASN suggests a number of ways of improving how a record and a trace of the presence of mining waste rock in the public domain can be maintained.

Evaluation of the dosimetric and environmental impact of mining waste rock

ASN recommends that Orano Mining finalise the study on the long-term evolution of the mining waste rock piles created by the former uranium mines, so that lessons can be learned and shared with the local actors.

ASN recalls that the radon exposure situations liable to be of natural origin, identified during the survey of mining waste rock in the public domain, should be the subject of appropriate remediation work.