Abstract
The apparent diffusion coefficients of La, Nd, Eu, Dy, Er, and Lu in compacted bentonites were investigated at various bicarbonate concentrations. The apparent diffusion coefficients of these lanthanides tended to decrease with increasing dry density. At bicarbonate concentrations below 0.25 M, lanthanum had the largest diffusion coefficient (ca. 10-13 m2/s) at 1.0 Mg/m3, and the diffusion coefficient decreased with increasing atomic number. On the other hand, at bicarbonate concentrations above 0.25 M, lutetium had the largest diffusion coefficient, and the diffusion coefficient decreased with decreasing atomic number. In particular, lanthanum and neodymium had diffusion coefficients below 10-14 m2/s, even at 1.0 Mg/m3. The diffusion coefficient of europium was around 10-13 m2/s at 1.0 Mg/m3 and was influenced less by the bicarbonate concentration. The diffusion coefficient of lutetium increased from 2 × 10-14 to 10-12 m2/s as the bicarbonate concentration was increased to 1.0 M. The concentration of carbonate ion in the pore water of bentonite is estimated to be much lower than that in solutions in contact with bentonite from the viewpoints of solubility and chemical species of lanthanides.
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References
JNC, H12: Project of Establish the Scientific and Technical Basis for HLW Disposal in JAPAN, JNC, Tokai Japan (2000).
James I. Drever, The Geochemistry of Natural Waters 3rd edition, (Prentice Hall, New Jersey, USA, 1997) Ch.4.
K. Idemitsu, X. Xia, T. Ichishima, H. Furuya, Y. Inagaki, T. Arima et al., in Scientific Basis for Nuclear Waste Management XXIII, edited by Robert W. Smith, David W. Shoesmith (Mater. Res. Soc. Proc. 608, Boston, MA, 2000) pp.261–266.
K. Idemitsu, H. Kozaki, M. Yuhara, T. Arima, Y. Inagaki, Progress in Nuclear Energy, 92, 279–285(2016).
K. Spahiu and J. Bruno, SKB Technical Report 95-35 (1995) pp. 24–54.
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Idemitsu, K., Fujii, K., Maeda, N. et al. Effect of Carbonate on the Migration Behavior of Lanthanides in Compacted Bentonite. MRS Advances 3, 1155–1160 (2018). https://doi.org/10.1557/adv.2018.184
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DOI: https://doi.org/10.1557/adv.2018.184