In place experiments on clayish terrains

Several countries have considered pelitic formations as host medium for some radioactive waste diposal. However, as far as high activities are concerned, they have only encountered limited interest. Some laboratories in North America and in Europe have launched R and D programmes, but most of them were limited to sample characterisation and some heat transfer experiments at shallow depth. Two exceptions however, Italy which has pursued its investigations since several years now develops a construction project for an underground laboratory in a marly clay in Sicily, and Belgium which has just completed such a facility at 240 m depth in a plastic clay layer. Some details concerning the construction and the measurement and in place experiments forseen or underway are given in the present paper. 14 refs.; 5 figs.; 1 table