Analyses of Two Deep-Geological-Disposal Concepts for CANDU Spent Nuclear Fuels Using Storage Baskets

Jongyoul Lee^*, Heuijoo Choi, Changsoo Lee, Jeong-Woo Kim, Seonghoon Ji, Dongkeun Cho

Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057, Republic of Korea

Received 2024-05-20 ; Revised 2024-06-11 ; Approved 2024-06-28

Abstract

In Korea, two types of spent nuclear fuels (SNFs) are generated, pressurized light water reactor type (PWR) and pressurized heavy water reactor type (PHWR; CANDU), that differ greatly in size, decay heat, and radioactive characteristics. Technology development for the disposal of SNFs has mainly focused on PWR SNFs that are large in size and have extremely high decay heat and radioactivity. However, CANDU SNFs should be considered differently from PWR SNFs in deep geological disposal systems because their characteristics significantly differ from those of PWR SNFs in terms of their dimensions, number of SNF bundles, and handling systems in nuclear power plant sites. In this paper, after reviewing the status of the CANDU SNF disposal concept by Canada and Korea, concepts related to the direct geological disposal of CANDU SNFs were described, and two concepts were proposed based on the results of the development. The engineered barrier systems developed using these two concepts were comparatively analyzed in terms of disposal safety, disposal efficiency, and technical maturity. Based on the results of the comparative analyses, a vertical-type emplacement disposal concept was determined as a reference concept for the deep geological disposal of CANDU SNFs.

Key Words : Spent nuclear fuels, CANDU bundles, Geological disposal concept, Engineered barrier system, Vertical emplacement, Horizontal emplacement, Reference disposal concept