EFFECT OF DRY DENSITY ON TECHNETIUM DIFFUSION IN COMPACTED BENTONITE |
Jae Owan Lee†, Won Jin Cho, and Chul Hyung Kang |
Korea Atomic Energy Research Institute, Daejeon 305-353, Korea |
Corresponding Author:
Jae Owan Lee ,Tel: +82-42-868-2852, Fax: +82-42-868-8850, Email: jolee@kaeri.re.kr |
Received: June 16, 2002; Accepted: October 16, 2002. |
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ABSTRACT |
Bentonite is widely favored as a buffer material of HLW (high-level waste) repository. Diffusion tests were conducted to investigate the diffusion of technetium in compacted bentonite. The tests were under oxidizing condition and the dry densities of compacted bentonite were 1.4, 1.6, and 1.8 Mg/mJ. The values of measured apparent diffusion coefficients ranged from 3.46 x 10"" m7s to 9.46x10"" m2/s, and they decreased with increasing the dry density. With no sorption on the bentonite, the diffusion of technetium was dependent on the pore structure of compacted bentonite, and it was also affected by anion exclusion between the technetium in the form of TcCV and the bentonite particle with negative surface charge. The results obtained will be used for the safety assessment of a repository. |
Keywords:
compacted bentonite | diffusion coefficient | technetium |
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