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Natural-Analog Studies for Partial Validation of Conceptual Models of Radionuclide Retardation at the Wipp

Published online by Cambridge University Press:  28 February 2011

David B. Ward
Affiliation:
Department of Geology, University of New Mexico, Albuquerque, NM 87131
Douglas G. Brookins
Affiliation:
Department of Geology, University of New Mexico, Albuquerque, NM 87131
Malcolm D. Siegel
Affiliation:
Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185
Steven J. Lambert
Affiliation:
Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185
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Abstract

Transport by groundwater within the Culebra Dolomite, an aquifer above the Waste Isolation Pilot Plant (WIPP), is the most probable mechanism for long-term release of radionuclides to the accessible environment. Radionuclides could be retarded by sorption if the groundwater is exposed to sufficient amounts of fracture-lining clays. In this natural-analog study, distributions of U and trace metals have been examined to constrain the strength of clay/solute interactions within the Culebra.

Uranium solid/liquid distribution ratios, calculated from U concentrations of groundwaters and consanguineous fracture-filling clays, range from ∼80 to 800 mℓ/g and imply retardation factors of 60 to 500 using a fracture-flow model. Retardation factors inferred from uranium-series disequilibria and 14C ages in Culebran groundwaters alone are much lower (∼10), implying that clays may contain a significant unreactive component of U. Such a possibility is corroborated by Rb/Sr ages; these imply long-term stability of the clays, with resetting occurring more than 250 Ma ago. Factor analysis and mass-balance calculations suggest, however, that Mg-rich clays are dissolving in Pleistocene-age groundwaters and/or are converting to Na-rich smectites, and that B and Li are taken up from the water by the clays. Apparently, the solution chemistry reflects gradual equilibration of clays with groundwater, but thus far the bulk of the clays remain structurally intact. Measurements of the distribution of U in the Culebra will be more meaningful if the inert and exchangeable components of the U content of the clays can be quantified.

Type
Research Article
Copyright
Copyright © Materials Research Society 1991

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References

REFERENCES

1. Lambert, S.J., Dissolution of Evaporites In and Around the Delaware Basin, Southeastern New Mexico and West Texas (Sandia Nat. Labs., SAND82-0461, 1983), 96 pp.Google Scholar
2. Lambert, S.J., Mat. Res. Soc. Symp. Proc., 15, 291298 (1983).Google Scholar
3. Sewards, T., Brearly, A., Glenn, R., MacKinnon, I.D.R., Siegel, M.D., Nature and Genesis of Clay Minerals of the Rustler Formation in the Vicinity of the Waste Isolation Pilot Plant, Southeastern New Mexico (Sandia Nat. Labs., SAND90-2569, in prep.).Google Scholar
4. Jones, B.F., Weir, A.H., Clays and Clay Minerals, 31. 161172 (1983).CrossRefGoogle Scholar
5. Siegel, M.D., Leckie, J.O., Park, S.W., Phillips, S.L., Sewards, T., in Waste Management 90, (Univ. of Arizona Press, 1990).Google Scholar
6. Park, S.-W., Leckie, J.O., Siegel, M.D., Surface Complexation Modeling of Uranyl Adsorption on Corrensite from the WIPP Site (Sandia Nat. Labs., SAND90-7084, in prep.).Google Scholar
7. Lambert, S.J., Carter, J.A., Uranium-Isotope Systematics in Groundwaters of the Rustler Formation, Northern Delaware Basin, Southeastern New Mexico – I: Principles and Preliminary Results (Sandia Nat. Labs., SAND87-0388, 1987), 15 pp.Google Scholar
8. Brookins, D.G., Lambert, S.J., Ward, D.B., in Scientific Basis for Nuclear Waste Management XIII, edited by Oversby, V. (El Sevier Science Publishers, 1989).Google Scholar
9. Bodine, M.W. Jr. and Jones, B.F. in Fluid-Mineral Interactions: A Tribute to Hans P. Eugster, edited by Spencer, R.J. and Chou, I-Ming (The Geochem. Soc., Spec. Pub. 2, 1990), pp.213269.Google Scholar
10. Lambert, S.J., Feasibility Study: Applicability of Geochronological Methods involving Radiocarbon and Other Nuclides to the Groundwater Hydrology of the Rustler Formation, Southeastern New Mexico (Sandia Nat. Labs, SAND86-1054, 1987), 128 pp.Google Scholar
11. Neretnieks, I., Rassmusson, A., Water Resources Res., 20, pp. 18231836 (1984).Google Scholar
12. Sewards, T., Characterization of Fracture Surfaces in Dolomite Rock, Culebra Dolomite Member, Rustler Formation (Sandia Nat. Labs. SAND90-7019, in prep.)Google Scholar
13. Krishnaswami, S., Graustein, W.C., Turekian, K.K., Dowd, J.F., Water Resources Res. 18, 16631675 (1982).Google Scholar
14. Evans, G.V., Otlet, R.L., Downing, R.A., Monkhouse, R.A., Rae, G., in Proceedings of the International Symposium of Isotope Hydrology, STI/PUB/493, v.2 (Int. Atomic Energy Agency, Vienna, 1979), pp.679706.Google Scholar
15. Osmond, J.K., Cowart, J.B., Atomic Energy Review, 14, 621679 (1976).Google Scholar
16. Andrews, J.N. and Kay, R.L.F., Earth Plan ScL Ltrs. 57, 139151 (1982).Google Scholar
17. Dosch, R.G., Solubility and Sorption Characteristics of Uranium (VI) associated with Rock Samples and Brines/Groundwaters from WIPP and NTS (Sandia National Laboratories, Report SAND80-1595, 1981), 30 pp.Google Scholar
18. Simpson, H.J., Trier, Y.-H., Anderson, R.F., Herczeg, A.L., Field experiment determinations of distribution coefficients of actinide elements in alkaline lake environments (NUREG/CR-3940, 1984), 114 pp.Google Scholar
19. Hubbard, N., Laul, J.C., Perkins, R.W., in Scientific Basis for Radioactive Waste Management VII, (Elsevier Science Publishers, New York 1984), pp.891897.Google Scholar
20. Laul, J.C., Smith, M.R., Rod. Waste Manag. and the Nuc. Fuel Cycle, 11, 169225 (1988).Google Scholar
21. Siegel, M.D., Robinson, K.L., Myers, J., in Hydrogeochemical Studies of the Rustler Formation and Related Rocks in the WIPP Area, Southeastern New Mexico, edited by Siegel, M.D., Lambert, S.J., and Robinson, K.L. (Sandia Nat. Labs., SAND88-0196, 1990).Google Scholar
22. Clovan, J.E., in Concepts in Geostatistics, edited by McCamon, R. (Springer-Verlag, New York 1975), pp.2169.Google Scholar
23. Spencer, R.J., Eugster, H.P., Jones, B.F., Geochim. Cosmochim. Acta, 49, 739747 (1985).Google Scholar
24. Smith, G.I., in Lithium Resources and Requirements by the Year 2000, edited by Vine, J.D. (U.S. Geol. Survey Prof. Paper 1005, 1976).Google Scholar
25. Smith, C.L., ibid.Google Scholar
26. Siegel, M.D., ed., Characterization of Rocks and Waters Along Potential Radionuclide Transport Paths Within the Rustler Formation in the Vicinity of the Waste Isolation Pilot Plant (Sandia Nat. Labs., SAND902520, in prep.).Google Scholar
27. Parkhurst, D.L., Plummer, L.N., Thorstenson, D.C., BALANCE – A Computer Program for Calculating Mass Transfer for Geochemical Reactions in Ground Water (U.S. Geol. Survey Water-Res. Inves. 82-14, 1982), 29 pp.Google Scholar