The scientific, technical, and sociopolitical challenges of finding a secure site for a geological repository for radioactive wastes have created a long and stony path for many countries. Japan carried out many years of research and development before taking its first steps in site selection. The Nuclear Waste Management Organization of Japan (NUMO) began looking for a high-level waste repository site (HLW, vitrified residue from reprocessing power reactor fuel) 2 years ago. Over the next 10-20 years, NUMO hopes to find a site to dispose of ˜20,000 tons of HLW in a robustly engineered repository constructed at a depth of several hundred meters.