What really happens to the “vanishing overpack”?

摘要: Concepts for the disposal of high-level radioactive waste (HLW) and spent fuel (SF) in several countries include a massive steel overpack within bentonite buffer. In past conservative safety assessments to demonstrate feasibility geological disposal, overpacks are assumed provide complete containment given lifetime, after which all fail simultaneously. After failure, they ignored as physical barriers radionuclide transport. order compare different repository designs specific sites, however, more realistic treatment failure its subsequent behaviour is needed. addition arguing much longer lifetimes before mechanical distribution times, such assessment indicates that presence failed greatly constrains release from matrix migration through engineered barrier system. It also emphasises key role buffer need be able assure performance over relevant timescales.