ABSTRACT
The geological disposal of high-level radioactive waste (HLW) is considered to be a global standard disposal method. Japanese government policy for such geological disposal states that HLW is to be buried very deep in the ground, i.e., more than 300 m, using a multi-barrier system. Compacted bentonite is one of the promising buffer materials for the artificial barrier, which is expected to be able to hold the overpack of HLW and to prevent the leakage of nuclide from the overpack over a period of ten to one hundred thousand years.
