THE FRENCH EXPERIENCE IN LOW-LEVEL RADIOACTIVE-WASTE MANAGEMENT

The Radioactive Waste Management Agency.(ANDRA-FRANCE) is now operatin g a new facility in the eastern part of the Paris basin which is desig ned to dispose of one million cubic meters of waste. The safety of the waste disposal is based on a multibarrier concept including waste pac kages, concrete disposal modules, site and closure operations. Under n ormal conditions, confinement is guaranteed by the waste packages and the disposal modules, as they prevent the waste from being leached by rainfall or underground water over a certain period of time. The site must bring an additional guarantee concerning the isolation of waste f rom water. Consequently, the chosen site must be located in an area wh ere no natural disasters (landslides, earthquakes, etc.) can harm the isolating barriers. The geological, hydrogeological and chemical chara cteristics must allow us to minimize and control the transport of radi onuclides within the ground. Finally, the chosen site must be in an ar ea where it is easy to implement a system to monitor the environment. A set of criteria guides the choice of site. The criteria include such factors as low seismicity, geotechnical stability, a hydrogeology tha t is simple to model, a location sufficiently above the water table an d safe from the threat of flooding, good radionuclide sorption and the absence of any mineral or other natural resources of economic interes t. At the time of the closure of the disposal facility, the entire col lection of modules will be covered by an impervious cap composed of cl ayey layers interbedded by sandy layers and overlain by humus to promo te the growth of grass. The facility will then look like a succession of undulating green mounds. A 300-year monitoring period will follow t he closure. During this period, the water collecting networks and cap will be maintained and radioactivity in underground and stream water w ill be controlled. We have selected the AUBE site as a case study to i llustrate the French waste management experience. We will report on ho w the site characterization program has been carried out, including th e hydrogeological modelling which is being applied to both the operati ng and post-closure periods.