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Diffusion of Cs, Np, Am and Co in compacted sand-bentonite mixtures: evidence for surface diffusion of Cs cations

  • T. Sawaguchi (a1), T. Yamaguchi (a1), Y. Iida (a1), T. Tanaka (a1) and I. Kitagawa (a2)...

Abstract

We studied the diffusive transport of Cs, Np, Am and Co in compacted sandbentonite mixtures by using the through-diffusion method. The experiments for Cs were performed under various aqueous compositions. Effective diffusivity (De ) values of 4.7×10–10 to 5.9×10–9 m2 s–1 were obtained with a somewhat large variation. Apparent diffusivity (Da) values, on the other hand, showed less variation, ranging from 2.0×10–12 to 6.2×10–12 m2 s–1. The results indicated that diffusive flux was proportional to the concentration gradient on the basis of the amount of Cs in the unit volume of the compacted sand-bentonite mixtures rather than the Cs concentration gradient in pore water. Because the former concentration gradient in the mixtures was nearly equal to that of adsorbed Cs, the diffusion of Cs in the mixtures was probably dominated by the concentration gradient of the Cs adsorbed on the mixtures. In addition, the effective/apparent diffusivity of 237Np(IV) and apparent diffusivity of 241Am(III) and 60Co(II) in the mixtures were determined in 0.3/0.03 mol l–1 (NH4)2CO3/Na2S2O4 solution.

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      Diffusion of Cs, Np, Am and Co in compacted sand-bentonite mixtures: evidence for surface diffusion of Cs cations
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Copyright

Copyright © The Mineralogical Society of Great Britain and Ireland 2013 This is an Open Access article, distributed under the terms of the Creative Commons Attribution license. (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Footnotes

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Part of this study was funded by the Secretariat of Nuclear Regulation Authority, Nuclear Regulation Authority, Japan.

Footnotes

References

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Brakel, J.V. & Heertjes, P.M. (1974) Analysis of diffusion in macroporous media in terms of a porosity, a tortuosity and a constrictivity factor. International Journal of Heat and Mass Transfer, 17, 1093–1103.
Crank, J. (1975) The Mathematics of Diffusion, 2nd edition, p. 13. Clarendon Press, Oxford.
Eriksen, T.E. & Jansson, M. (1996) Diffusion of I–, Cs+ and Sr2+ in compacted bentonite – Anion exclusion and surface diffusion. SKB Technical Report 96-16, Swedish Nuclear Fuel and Waste Management Company.
Foti, S.C. & Freiling, E.C. (1964) The determination of the oxidation states of tracer uranium, neptunium and plutonium in aqueous media. Talanta, 11, 385–392.10.1016/0039-9140(64)80047-3
Ito, M., Okamoto, M., Shibata, M., Sasaki, Y., Danhara, T., Suzuki, K. & Watanabe, T. (1993) Mineral Composition Analysis of Bentonite. PNC TN 8430 93-003, Power Reactor and Nuclear Fuel Development Corporation [in Japanese].
JAEA (2006) H17 Research on long-term safety assessment methodology for radioactive waste disposal – Research on probabilistic approach to longterm safety assessment methodology. Japan Atomic Energy Agency [in Japanese].
JNC (2000) H12 Project to Establish the Scientific and Technical Basis for HLW Disposal in Japan, Project Overview Report, 2nd Progress Report on Research and Development for the Geological Disposal of HLW in Japan. JNC Technical Report TN1410 2000-001, Japan Nuclear Cycle Development Institute.
Kato, H., Nakazawa, T., Ueta, S. & Yato, T. (1999) Measurements of effective diffusivities of tritiated water in sand-mixed bentonite. Proceedings of the 7th International Conference on Radioactive Waste Management and Environmental Remediation- ASEM 1999, Nagoya, Japan, September 26-30, 1999.
Kozaki, T., Sato, H., Sato, S. & Ohashi, H. (1999) Diffusion mechanism of cesium ions in compacted montmorillonite. Engineering Geology, 54, 223–230.10.1016/S0013-7952(99)00077-0
Muurinen, A., Penttilä-Hiltunen, P. & Rantanen, J. (1987) Diffusion mechanisms of strontium and cesium in compacted sodium bentonite. Pp. 803–812 in: Scientific Basis for Nuclear Waste Management X, Materials Research Society Symposium Proceedings (Bates, J.K. & Seefeldt, W.B., editors), 84.
Neretnieks, I. (1980) Diffusion in the rock matix: an important factor in radionuclide retardation? Journal of Geophysical Research, 85, 4379–4397.
Okamoto, A., Idemitsu, K., Furuya, H., Inagaki, Y. & Arima, T. (1999) Distribution coefficients and apparent diffusion coefficients of cesium in compacted bentonites Pp. 1091–1098 in: Materials Research Society Symposium, 556, Scientific Basis for Nuclear Waste Management, 22 (David, W.& Lee, J.H., editors).
Sato, H., Ashida, T., Kohara, Y., Yui, M. & Sasaki, N. (1992) Effect of dry density on diffusion of some radionuclides in compacted sodium bentonite. Journal of Nuclear Science and Technology, 29, 873–882.10.1080/18811248.1992.9731607
Sawaguchi, T., Takeda, S., Kozaki, T., Sekioka, Y., Kato, H. & Kimura, H. (2006) Assessment of data uncertainty on the diffusion coefficients for nuclides in engineered and natural barriers. Pp. 21–26 in: JAEA-Conf 2008-001, Proceedings of the International Information Exchange Meeting on Diffusion Phenomena in Bentonite and Rock; Aiming at the Safety Assessment of the Geological Disposal (Sato, H. & Hatanaka, K., editors), July 18, 2006, Horonobe, Japan.
Yamaguchi, T. (2000) Consideration of thermodynamic data for predicting solubility and chemical species of elements in groundwater. Part 2: Np, Pu. JAERIData/ Code 2000-031, Japan Atomic Energy Research Institute [in Japanese].
Yamaguchi, T., Nakayama, S., Nagao, S. & Kizaki, M. (2007) Diffusive transport of neptunium and plutonium through compacted sand-bentonite mixtures under anaerobic conditions. Radiochimica Acta, 95, 115–125.10.1524/ract.2007.95.2.115
Yu, J-W. & Neretnieks, I. (1997) Diffusion and sorption properties of radionuclides in compacted bentonite. SKB Technical Report 97-12, Swedish Nuclear Fuel and Waste Management Company.
Zhang, M. & Takeda, M. (2005) Theoretical evaluation of the through-diffusion test for determining the transport properties of geological materials. Proceedings of Waste Management Symposium 2005, February 27–March 3, 2005, Tucson, Arizona, USA.

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