DOE OSTI2013
Since 2004, AREVA's subsidiary SICN has been conducting the cleanup and dismantling of an old uranium foundry located in the town of Annecy (France). The first operations consisted in the removal of the foundry's production equipment, producing more than 300 metric tons (MT) of waste. The second step consisted in performing the radiological characterization of the 1,600 m{sup 2} (17,200 ft{sup 2}) building, including underground trenches and galleries. The building was precisely inventoried, based on operations records and direct measurements. All sub-surfaces, which needed to be cleaned up were characterized, and a determination of the contamination migration was established, in particular with trenches and galleries. The wall thicknesses to be treated were empirically justified, knowing that the maximal migration depth inside concrete is 5 mm for a liquid transfer vector. All singularities such as cracks, anchoring points, etc. were spotted for a complete and systematic treatment. Building structures not laying directly on the soil, such as floor slabs, were not cleaned up but directly deconstructed and disposed of as waste. The facility was located within the town of Annecy. Therefore, in order to avoid the risk of dusts dispersion and public exposure during the building deconstruction and the soil treatment, a third of the building's surface was confined in a sliding airlock built from a metal structure capable of resisting to wind and snow, which are frequent in this area. This particular structure provided a static confinement over the half of the building which was covered and a dynamic confinement using a ventilation and high efficiency air filtration system, sized to provide 2.5 air changes per hour. The enclosure and its metallic structure is 33 m long (108 feet), 25 m wide (82 feet), and 13 m high (42 feet), for a volume of 10,000 m{sup 3} (353,000 ft{sup 3}). It was made up of a double skin envelope, allowing the recycling of its structure and outside envelope. After cleaning up and dismantling the first portion of the building, the enclosure was repositioned on the second and the last third of the building, by sliding it on support pads. Almost 7,000 m{sup 2} of concrete surface has been treated with no dust dispersion outside the enclosure. After treatment, all the remaining surfaces were controlled by an independent entity to verify their acceptability with regards to residual contamination (less than 0.4 Bq/cm{sup 2} (24 DPM) for alpha contamination and less than 1 Bq/g of total uranium). Approximately 1,900 MT of equipment and waste were generated in batches of 1m{sup 3}, in order to be staged on site, and then characterized and packaged in 20 foot containers for shipment to the final ANDRA repository. The package certification included the verification of the physical and chemical characteristics and the radiological characteristics (mass activity, dose rate, and residual outside surface contamination). Finally, after cleanup and dismantling of the foundry, a concrete slab was poured on the free surface as a clean base for implementation of new activities. (authors)
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗