Hostname: page-component-848d4c4894-nr4z6 Total loading time: 0 Render date: 2024-06-12T09:55:36.340Z Has data issue: false hasContentIssue false
  • English
  • Français

Low-Temperature Mobility of Rare Earth Elements (REE), U, and Th at the Olkiluoto Site, SW Finland

Published online by Cambridge University Press:  21 March 2011

Nuria Marcos
Nuria Marcos*
Affiliation:
Helsinki University of Technology, P.O. Box 6200, FIN-02015 HUT, Finland
Get access

Abstract

This work is a first effort to link hydrogeological measurements to structural modeling by using the mobility of rare earth element (REE), U, and Th at the Olkiluoto site. REE, U and Th concentrations were measured in 5 groundwater samples located at depths varying between 132 and 446 m in three drill holes at the Olkiluoto site. The pH of groundwater samples are all about 8 and Eh(Pt) varies from –50 to –200 mV. Also the REE, U and Th concentrations of rock samples collected from core sections in the vicinity of water conducting fractures were measured to examine rock-water interactions in the system. The rock samples were cut into slices parallel to the fracture surface. An aliquot of each slice was leached with 0.5 N acid nitric to examine the readily leachable REE, U and Th fraction of each slice. The groundwater samples were normalized to each of the analyzed rock samples. Although the REE concentrations of the water samples are overall depleted in all the REEs compared to the rocks and leachates, and whole REE spectra could not be obtained for any of the groundwater samples, enrichment in the intermediate REE (IREE) with respect to the light REE (LREE) is observed.

An increasing loss of REE and U from rock matrix towards fracture surface is observed in samples at depths of 141, 159, and 466 m. Loss of U is also observed in a sample at about 246 m depth. Loss of Th is only observed at the depths of 159 and 246 m. The loss of U (readily leachable fraction) in the rock samples was found to be linked to the hydraulic conductivity in the related water-conducting fractures.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 713: Symposium JJ – Scientific Basis for Nuclear Waste Management XXV , 2002 , JJ8.2
Copyright
Copyright © Materials Research Society 2002

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

1. Choppin, G.R., J. Less-Common Metals 93, 232–330 (1983).Google Scholar
2. Brookins, D.G., Chem. Geol. 55, 337–344 (1986); K.B. Krauskopf, 55, 323–336 (1986).Google Scholar
3. Äikäs, T., in Rock Mechanics – A Challenge for Society, edited by Särkkä, P. and Eloranta, P. (A.A. Balkema Publishers, The Netherlands, 2001) pp. 3–11, (2001).Google Scholar
4. Pitkänen, P., Luukkonen, A., Leino-Forsman, H. and Vuorinen, U., POSIVA Report 98-10, 184 p. (1999).Google Scholar
5. Johannesson, K.H. and Zhou, X., Geochim. Cosmochim. Acta 63, 153–165 (1999).Google Scholar
6. Taylor, S.R. and McLennan, S.M., The Continental Crust, Blackwell, Oxford, 312 p. (1985).Google Scholar
7. Taylor, S.R. and McLennan, S.M., in Handbook on the Physics and Chemistry of Rare Earths, Eds. Gshneider, K.A. Jr and Eyring, L., 11, pp. 485–578, Elsevier, Amsterdam (1988).Google Scholar
8. Pöllänen, J. and Rouhiainen, P., POSIVA Work Report PATU-96-43e, (1996).Google Scholar
9. Smedley, P.L., Geochim. Cosmochim. Acta 55, 2767–2779 (1991); K.H. Johannesson, K.J. Stetzenbach, and V.F. Hodge, 61, 3605–3618 (1997).Google Scholar
10. Fee, J.A., Gaudette, H.E., Lyons, W.B., and Long, D.T., Chem. Geol. 96, 67–93 (1992).Google Scholar
11. Johannesson, K.H. and Lyons, W.B., Chem. Geol. 119, 209–223 (1995); K.H. Johannesson, W.B. Lyons, M.A. Yelken, H.E. Gaudette, and K.J. Stetzenbach, 133, 125–144 (1996).Google Scholar
12. Gosselin, D.C., Smith, M.R., Lepel, E.A., and Laul, J.C., Geochim. Cosmochim. Acta 56, 1495–1505 (1992).Google Scholar
13. Wood, S.A., Chem. Geol. 82, 159–186 (1990).Google Scholar
14. Roaldset, E., Geochim. Cosmochim. Acta 39, 455–469 (1975).Google Scholar
15. Rouhianen, P., POSIVA Working Report 99–72, (2000).Google Scholar
16. Ahokas, H., Luukkonen, A., Korkealaakso, J., Ristila, R., Kuusela-Lahtinen, A., Laitinen, M., and Ylinen, A.. POSIVA Work Report PATU-96–92, (1997).Google Scholar
17. Marcos, N., in International Conference on the Safety of Radioactive Waste Management, IAEA-CN-78, 120–123 (2000).Google Scholar
18. Blomqvist, R., Ruskeeniemi, T., Kaija, J., Ahonen, L., Paananen, M., Smellie, J., Grundfelt, B., Pedersen, K., Bruno, J., Villar, L. Pérez del, Cera, E., Rasilainen, K., Pitkänen, P., Suksi, J., Casanova, J., Read, D. and Frape, S., The Palmottu natural analogue project. Phase II. EUR 19611 EN. 174 p. (2000).Google Scholar