Low Level Waste Conceptual Design Adaption to Poor Geological Conditions

Conference · Tue Feb 26 04:00:00 EST 2002

OSTI ID:828314

Bell, J; Drimmer, D; Giovannini, A; Manfroy, P; Maquet, F; Schittekat, J; Van Cotthem, A; Van Echelpoel, E

Since the early eighties, several studies have been carried out in Belgium with respect to a repository for the final disposal of low-level radioactive waste (LLW). In 1998, the Belgian Government decided to restrict future investigations to the four existing nuclear sites in Belgium or sites that might show interest. So far, only two existing nuclear sites have been thoroughly investigated from a geological and hydrogeological point of view. These sites are located in the North-East (Mol-Dessel) and in the mid part (Fleurus-Farciennes) of the country. Both sites have the disadvantage of presenting poor geological and hydrogeological conditions, which are rather unfavorable to accommodate a surface disposal facility for LLW. The underground of the Mol-Dessel site consists of neogene sand layers of about 180 m thick which cover a 100 meters thick clay layer. These neogene sands contain, at 20 m depth, a thin clayey layer. The groundwater level is quite close to the surface (0-2m) and finally, the topography is almost totally flat. The upper layer of the Fleurus-Farciennes site consists of 10 m silt with poor geomechanical characteristics, overlying sands (only a few meters thick) and Westphalian shales between 15 and 20 m depth. The Westphalian shales are tectonized and strongly weathered. In the past, coal seams were mined out. This activity induced locally important surface subsidence. For both nuclear sites that were investigated, a conceptual design was made that could allow any unfavorable geological or hydrogeological conditions of the site to be overcome. In Fleurus-Farciennes, for instance, the proposed conceptual design of the repository is quite original. It is composed of a shallow, buried concrete cylinder, surrounded by an accessible concrete ring, which allows permanent inspection and control during the whole lifetime of the repository. Stability and drainage systems should be independent of potential differential settlements an d subsidences. Potential radionuclides releases are controlled and have a single discharge point to the biosphere.

• Research Organization: ONDRAF/NIRAS, the Belgian National Waste Management Agency (BE); TRACTEBEL DEVELOPMENT ENGINEERING, BELGATOM and KUL, Leuven University (BE); TRACTEBEL DEVELOPMENT ENGINEERING AND BELGATOM (BE)
• Sponsoring Organization: Sponsor not identified (US)
• OSTI ID: 828314
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
BIOSPHERE
CLAYS
COAL SEAMS
CONCRETES
DRAINAGE
LIFETIME
LOW-LEVEL RADIOACTIVE WASTES
METERS
RADIOISOTOPES
SAND
SHALES
SILT
STABILITY
TOPOGRAPHY
WASTE MANAGEMENT