In situ diffusion experiment in mudstone at the Horonobe URL; Comparative study between in situ and laboratory tests
幌延URLにおける泥岩中の原位置拡散試験; 原位置と室内試験の比較評価
舘 幸男 ; 武田 匡樹 ; 大野 宏和 ; 伊藤 剛志*; 佐藤 智文*; 根本 一昭*
Tachi, Yukio; Takeda, Masaki; Ono, Hirokazu; Ito, Tsuyoshi*; Sato, Tomofumi*; Nemoto, Kazuaki*
Diffusion and sorption of radionuclides in potential host rocks are key processes controlling the safety of geological disposal of radioactive waste. Diffusion and sorption parameters have been derived from laboratory experiments using drilled or crushed rock samples. To set reliable parameters of diffusion and sorption relevant to performance assessment, it is necessary to understand in detail the processes of diffusion and sorption in laboratory and in situ conditions, and to confirm the consistency or the relationship of these parameters between both conditions. This paper presents new results of in situ diffusion test conducted in siliceous mudstone in the 350 m depth drift at Horonobe Underground Research Laboratory in Northern Hokkaido, Japan. In addition, laboratory diffusion tests were conducted using core samples from the site of in situ test. Diffusion and sorption parameters were derived and compared between in situ and laboratory tests.