Abstract
Based on the recognition that layout elements of a repository are important factors to govern total costs of the high-level radioactive waste disposal, the study on their feasibility has made as a trial from the view points of economics, shielding, strength against pressure, retention capability and especially mechanical interactions within near-field under some premises and conditions discribed below to establish an economical and rational repository concept.
(1) Host rocks: Granite (800m deep) and sedimentary (500m deep)
(2) Emplacement methods: Horizomtal
(3) Thickness of overpacks: 20cm
(4) Thickness of bentonite: 70cm
(5) Inner diameter of repository tunnel: 2.3m
(6) Center distance betweem repository tunnels: 20m
In addition, perceiving long-term behaviors of near field composed of waste package, overpack. bentonite and surrounding rock, some suggestions or tasks for each items above are also referred.
Among assumptions for these studies, there are some items, such as corrosion rate and performance of overpack, as well as mechanical properties of bentonite and so on, not comfirmed fully yet by experiments, and so studies are made under conservative assumptions for these items. Considering study results as a whole, the premises and conditions specified in these studies are concluded to be highly feasible.
