BELGIAN CONCEPT FOR HLW DISPOSAL: DEVELOPMENT AND DEMONSTRATION

The Belgian concept consists of an horizontal network of disposal galleries in a clay layer, the Boom Clay Formation. This tertiary clay formation is the subject of extensive research dealing with all phenomena that may possibly affect the performance of a potential disposal site, such as corrosion, migration, or climate changes. The safety assessment of the disposal concept is based on the results of this research. The uncertainty on these results may vary, due to the limitations of the laboratory research (e.g. scale effects in time and space), the spatial variation of properties in geological formations, or the identification of relevant phenomena. The perception of the general public of HLW disposal is an important factor, as final decisions have to be taken by the public authorities. When this perception is distorted by a misunderstanding of the available information, the process of decision-taking may be disturbed. Confidence building can be achieved by safety assessment, but should also be complemented by a more tangible demonstration of the concept, because the "seeing is believing"-factor must not be neglected. With this in mind, the Belgian Waste Agency NIRAS/ONDRAF and the Nuclear Energy