Optimising repository design for the CARE concept

Masuda, Sumio*; Kawamura, Hideki*; McKinley, I. G.*; Neall, F. B.*; Umeki, Hiroyuki

There has been increasing international interest in repository designs, particularly for high-level radioactive waste (HLW) or spent fuel (SF), which maintain the option of ease of retrieval for long periods of time. Such delayed closure may be driven by either a need to slowly gain social acceptance or a desire to maintain the future option of reprocessing of spent fuel in view of the resurgence of interest in nuclear power. In either case, there are advantages in repository concepts which are specifically developed with this requirement in mind, rather than attempting to modify designs developed under different boundary conditions. The CARE concept is an example of such a design. In the present paper, the basic concept is outlined and examined with respect to optimisation of both operational and post-closure safety.