H12: Project to Establish the Scientific and Technical Basis for HLW Disposal in Japan Project Overview Report
As outlined in the overall program for high-level waste (HLW) management in Japan, defined by the Atomic Energy Commission (AEC), HWL separated from spent nuclear fuel during reprocessing will be immobilized in a glass matrix and stored for a period of 30 to 50 years to allow cooling; it will then be disposed of in a stable deep geological formation.