Hostname: page-component-77c89778f8-cnmwb Total loading time: 0 Render date: 2024-07-21T02:26:44.456Z Has data issue: false hasContentIssue false
  • English
  • Français

Microbial Sulphide Production in Compacted Bentonite at the Commencement of Long-Term Disposal of High-Level Radioactive Waste

Published online by Cambridge University Press:  01 February 2011

Peter Masurat  and
Karsten Pedersen
Peter Masurat
Affiliation:
Göteborg University, CMB- Microbiology, Box 462, SE-405 30 Göteborg, Sweden; email: peter.masurat@gmm.gu.se, karsten.pedersen@gmm.gu.se
Karsten Pedersen
Affiliation:
Göteborg University, CMB- Microbiology, Box 462, SE-405 30 Göteborg, Sweden; email: peter.masurat@gmm.gu.se, karsten.pedersen@gmm.gu.se
Get access

Abstract

The use of nuclear reactors produces electrical power but also high-level radioactive waste (HLW). In Sweden it has been decided that the HLW shall be disposed of in a deep geological repository 500 meters underground. The HLW will be encapsulated in copper canisters, surrounded by bentonite and then the access tunnel will be backfilled with a bentonite and crushed rock mixture.

We have investigated activity of sulphate reducing bacteria (SRB) in compacted bentonite with densities of 1.5, 1.8 and 2.0 g·cm−3 using stainless steel oedometers with 35SO42- as the main sulphur source for the SRB. The investigations were performed under in situ conditions at a depth of 450 m at the Äspö Hard Rock Laboratory. Canister type copper plates were placed in the oedometers, with the top either in contact with the added groundwater or with 3–4 mm bentonite between the plate and the added groundwater. Radioactive hydrogen sulphide formed by the SRB reacted with the copper and formed radioactive copper sulphide, which was measured by electronic radiography using an Instant Image Micro autoradiography instrument (Packard). A similar set-up with filter-sterilized groundwater (0.2 μm) was used as control. A second experiment was set up as the first experiment but using only filtered groundwater and adding heat treatment of the bentonite in the control. Here, we show that SRB were active and produced hydrogen sulphide during the initial phase of bentonite swelling. The activity of the SRB was inversely correlated with the final density of the bentonite as the highest density had the lowest overall SRB activity. We also found that SRB were present in a dormant state in the commercial MX-80 bentonite. By addition of water, these dormant SRB became active and started to produce hydrogen sulphide.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 807: Symposium Scientific Basis for Nuclear Waste Management XXVII , 2003 , 805
Copyright
Copyright © Materials Research Society 2004

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. Pedersen, K. and Karlsson, F., Swedish Nuclear Fuel and Waste Management Co, SKB technical report 95–10, june 1995.Google Scholar
2. Haveman, S. A., Pedersen, K. and Ruotsalainen, P., Geomicrobiology Journal, pp. 277–294, 1999.Google Scholar
3. Banwart, S., Tullborg, E.-L., Pedersen, K., Gustafsson, E., Laaksoharju, M., Nilsson, A.-C., Wallin, B. and Wikberg, P., Journal of Contaminant Hydrology, vol. 21, pp. 115–125, 1996.Google Scholar
4. Kotelnikova, S. and Pedersen, K., Swedish Nuclear Fuel and Waste management Co., Stockholm, SKB Technical Report 99–17, 1999.Google Scholar
5. Pedersen, K., Eng. Geol., vol. 52, pp. 163–176, 1999.Google Scholar
6. Motamedi, M., Karland, O. and Pedersen, K., FEMS Microbiology Letters, vol. 141, pp. 83–87, 1996.Google Scholar
7. Pedersen, K., Motamedi, M., Karnland, O. and Sandén, T., J Appl Microbiol, vol. 89, pp. 1038–1047, 2000.Google Scholar
8. Widdel, F. and Bak, F., “Gram-negative mesophilic sulfate-reducing bacteria,” in The Prokaryotes, vol. 4, Balows, A., Trüper, H. G., Dworkin, M., Harder, W. and Schleifer, K.-H., Eds., 2 ed. New York: Springer-Verlag, 1992, pp. 3352–3378.Google Scholar
9. Stroes, G. S., Pedersen, K., Haveman, S. A., Dekeyser, K., Arlinger, J., Daumas, S., Ekendahl, S., Hallbeck, L., Hamon, C. J., Jahromi, N., and Delaney, T. L., Canadian Journal of Microbiology, vol. 43, pp. 1133–1146, 1997.Google Scholar