Determination of 75Se, 95Zr, 237Np and 241Am activities in Boom Clay samples from laboratory migration experiments using γ-ray spectrometry

Abstract Percolation tests (i.e. routine laboratory migration experiments) have been performed to evaluate the diffusion behaviour of a number of long-lived radionuclides in Boom Clay, a candidate geological host formation for high level radioactive waste (HLW) in Belgium. Among the many potentially hazardous radionuclides under investigation are 79 Se, 93 Zr, 237 Np, 241 Am and 243 Am. Actinide migration experiments have been carried out with 237 Np and 241 Am, while for the studies with Se and Zr the radioisotopes 75 Se and 95 Zr were used. Their transport patterns in the Boom Clay were examined using a combination of a NaI(Tl) detector and High-Purity Ge detectors either on the dissolved matrix ( 237 Np, 241 Am) or directly on the clay ( 75 Se, 95 Zr).