Analysis of the remediated sites

The sites of radioactive pollution for which the Agency intervenes are mainly former (ancient) installations having used or made radium or thorium and for most of which the owner can no longer be traced.

In two cases out of three, these sites have their origins in the prosperous interwar radium industry that involved factories for the extraction of radif — erous ore (Gif-sur-Yvette, Nogent-sur-Marne, Saint Denis island) or work­shops using radium products such as radioluminescent paints (e. g., in the watch-making industry or for clock manufacturing). The sites of the watch­making industry may also have tritium pollution following the replacement of radium by tritium in the 1960s. Other contaminated sites arise from rare earth extraction (thorium) and, more recently, manufacture of tracer mol­ecules (tritium and carbon-14, in particular).

The age of these sites frequently raises the problem of records of these activities, and lack of description of what has been allowed in the past (such as inappropriate use of sites from the point of view of radioprotection; see Fig. 15.2). Indeed, some of these sites are in densely housed areas, such as in Gif-sur-Yvette, and others can be found on the site of sensitive activities such as day nurseries, or schools. Other sites are in a safe state and await requalification. The problem of lack of records arises when intervention is envisaged. Mostly archives are unavailable, the owners of the site have often disappeared or died or refuse to communicate their knowledge. The inter­ventions thus have to base themselves on very precise mappings and sound­ings of grounds to know the state of pollution and, if necessary, analysis of

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(a)

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(b)

15.2 ( a) and (b) Examples of abandoned contaminated industrial sites.

subterranean waters. This stage of characterization is long and expensive, but is essential.

Naturally any zoning of the waste on these sites is impossible. Packages of waste have to be characterized on-site, taking into account the existing radioelements, the nature of the materials and the planned modes of con­ditioning. This can add technical difficulties in the case of lack of space or of raised levels of radiological protection. Most of the time the waste recov­ered is mainly VLLW and to a lesser extent, radiferous. Some cases are made even more complex, such as in the case of mixed chemical and radio­active waste, for which the solutions must be studied separately.

The great majority of sites are in the Paris region and in densely populated urban zones, so that the site cannot be reopened for industrial use. The ques­tion of the requalification of the site is directly linked to the definition of the rehabilitation objectives. This definition is the topic of discussion with the local safety authority. Also, the location of these sites in urban zones raises difficulties linked to the creation of a decommissioning construction site. This requires frequent contact with local authorities to find satisfactory solu­tions to the required limitation of hazards to the local residents. The charac­teristics and problems of these sites are closer to those of chemically polluted sites than to those of decommissioning in a nuclear environment.

ANDRA’ s missions in this domain are similar to those of the environ­mental agency in the field of chemical pollution, with comparable interven­tion mechanisms (although the number of sites is much smaller for ANDRA):

• There are about 20 radioactive contaminated sites for ANDRA and approximately 150 chemically polluted sites for the environmental agency requiring immediate intervention.

• In total there are about 50 sites of radioactive pollution against approxi­mately 4,000 sites of chemical pollution.

Operationally, ANDRA intervenes on sites at the request of public authori­ties. This requisition generally takes the shape of an order from the Depart­ment prefet based on the legislation for industrial landfills. The prefet makes this order after authorization from the Minister for Ecology. The interventions are made in close collaboration with the local administration concerned in the areas of safety, worker safety and industrial safety.

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