Studies of the setting of engineered barrier configuration utilized in geologic disposal

(2) Carbon steel overpack thickness

Abstract

  The thickness of overpack used in the high-level radioactive waste disposal is evaluated. The feasibility report on the geologic disposal in Japan suggested the very thick overpack because of the radiation shielding requirement. The overpack is not an essential material of waste package but has about 90% of the total weight of the waste package. Assumptions, data, and equation cited in the report are thus re-examined and the results indicate the dimension possibly reduced is 0.08m in thickness. This reduction is favorable to minimize several disadvantages such as the difficulty of handling during emplacement and the mechanical stress arising due to volume expansion during iron corrosion.