Abstract
Unsaturated vegetated soils are an important component in performance assessment models used to quantify risks associated with deep engineered repositories for underground radioactive waste disposal. Therefore, experimental studies, funded by Nirex over nearly 20 years, have been undertaken at Imperial College to study the transfer of radionuclides (Cl-36, I-129, Tc-99) from contaminated groundwater into crops. In parallel to this has been a modelling programme to aid interpretation of the experimental data, obtain parameter values characterising transport in soil and plant uptake and provide new representations of near-surface processes for performance assessment. A particular challenge in achieving these objectives is that the scale of the experimental work (typically ≤ 1m) is much smaller than that required in performance assessment. In this paper, a new methodology is developed for upscaling model results obtained at the experimental scale for use in catchment scale models. The method is based on characterising soil heterogeneity using soil texture. This has the advantage of allowing hydrological and radionuclide transport parameters to be correlated in a consistent manner. An initial investigation into the calculation of effective (i.e. upscaled) hydrological and transport parameters has been undertaken and shows the results to be potentially highly (and non-linearly) sensitive to soil properties. Consequently, they have important implications for future site characterisation programmes supporting a proposed underground waste repository.
Similar content being viewed by others
References
K. J. Beven, D. Zhang and A. Mermoud, Vadose Zone J. 5, 222–233 (2006).
A. P. Butler, B. M. Jackson, J. A. Tompkins and H. S. Wheater, Radionuclide Transport and Uptake in Vegetated Soils: Modelling the Phase II lysimeter experiment, Report ICSTM/NRP 002, Imperial College London (2002).
A. M. Ireson, S. A. Mathias and A. P. Butler, A Preliminary Investigation into Upscaling Radionuclide Migration and Uptake in Vegetated Soils, Report ICSTM/NRP 020, Imperial College London (2007).
R. A. Feddes, P. Kowalik, K. Kolinska-Malinka and H. Zaradny, J. Hydrol. 31, 13–26 (1976).
M. G. Schaap, F. J. Leij and T. van Genuchten, J. Hydrol. 251, 163–176 (2001).
M. T. van Genuchten, Soils, Soil Sci. Soc. America J. 44, 892–898 (1980).
H. Vereecken, R. Kasteel, J. Vanderborght and T. Harter, Vadose Zone J. 6, 1–28 (2007).
J. Zhu and B. P. Mohanty, Vadose Zone J. 3, 1464–1470 (2004).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Simon, A.M., Andrew, M.I., Adrian, P.B. et al. Characterisation of Radionuclide Migration and Plant Uptake for Performance Assessment. MRS Online Proceedings Library 1107, 681 (2008). https://doi.org/10.1557/PROC-1107-681
Published:
DOI: https://doi.org/10.1557/PROC-1107-681