Hostname: page-component-586b7cd67f-r5fsc Total loading time: 0 Render date: 2024-11-23T04:05:06.464Z Has data issue: false hasContentIssue false

Effect of Carbonate on the Migration Behavior of Lanthanides in Compacted Bentonite

Published online by Cambridge University Press:  13 February 2018

Kazuya Idemitsu*
Affiliation:
Dept. of Applied Quantum Physics and Nuclear Engineering, Kyushu Univ., 744 Motooka, Nishi-ku, Fukuoka, Japan
Kazuyuki Fujii
Affiliation:
Dept. of Applied Quantum Physics and Nuclear Engineering, Kyushu Univ., 744 Motooka, Nishi-ku, Fukuoka, Japan
Noriyuki Maeda
Affiliation:
Dept. of Applied Quantum Physics and Nuclear Engineering, Kyushu Univ., 744 Motooka, Nishi-ku, Fukuoka, Japan
Yuki Kakoi
Affiliation:
Dept. of Applied Quantum Physics and Nuclear Engineering, Kyushu Univ., 744 Motooka, Nishi-ku, Fukuoka, Japan
Noriya Okubo
Affiliation:
Dept. of Applied Quantum Physics and Nuclear Engineering, Kyushu Univ., 744 Motooka, Nishi-ku, Fukuoka, Japan
Yaohiro Inagaki
Affiliation:
Dept. of Applied Quantum Physics and Nuclear Engineering, Kyushu Univ., 744 Motooka, Nishi-ku, Fukuoka, Japan
Tatsumi Arima
Affiliation:
Dept. of Applied Quantum Physics and Nuclear Engineering, Kyushu Univ., 744 Motooka, Nishi-ku, Fukuoka, Japan
*
Get access

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.

Type
Articles
Copyright
Copyright © Materials Research Society 2018 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

JNC, H12: Project of Establish the Scientific and Technical Basis for HLW Disposal in JAPAN, JNC, Tokai Japan (2000).Google Scholar
Drever, James I., The Geochemistry of Natural Waters 3rd edition, (Prentice Hall, New Jersey, USA, 1997) Ch.4.Google Scholar
Idemitsu, K., Xia, X., Ichishima, T., Furuya, H., Inagaki, Y., Arima, T. et al. ., in Scientific Basis for Nuclear Waste Management XXIII, edited by Smith, Robert W., Shoesmith, David W. (Mater. Res. Soc. Proc. 608, Boston, MA, 2000) pp. 261266.Google Scholar
Idemitsu, K., Kozaki, H., Yuhara, M., Arima, T., Inagaki, Y., Progress in Nuclear Energy, 92, 279285(2016).CrossRefGoogle Scholar
Spahiu, K. and Bruno, J., SKB Technical Report 95-35 (1995) pp. 2454.Google Scholar