Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-25T17:49:11.105Z Has data issue: false hasContentIssue false
  • English
  • Français

The Influence of Ligands and Precipitates on the Release of Nuclides from the Near Field under Natural Repository Conditions

Published online by Cambridge University Press:  21 March 2011

L. Liu  and
I. Neretnieks
L. Liu
Affiliation:
Department of Chemical Engineering and Technology, Royal Institute of Technology, SE-100 44 Stockholm, Sweden
I. Neretnieks
Affiliation:
Department of Chemical Engineering and Technology, Royal Institute of Technology, SE-100 44 Stockholm, Sweden
Get access

Abstract

Once groundwater intrudes into a damaged canister and wets the spent fuel pellets, radiation emitted from the spent nuclear fuel splits nearby water into oxidizing and reducing species. This may lead to an oxidizing condition near the fuel pellets. As a result, uranium oxide that makes up the fuel matrix will become more soluble, and the incorporated radionuclides will be released more rapidly. The dissolution process is, however, a dynamic one that can be influenced by many factors. Of great importance are the radiation power of the fuel matrix, the concentration of ligands near the fuel surface, and the transport resistance of the near field. Consequently, the escape of nuclides from the damaged canister is dominated mainly by the intrusion of ligands, and the precipitation/dissolution of secondary phases within the fuel rods. To investigate the possible effects of ligands and precipitates, a coupled dissolution and transport model, which includes the barrier effect of the Zircaloy claddings, is developed. The application of the model to a SKB-specified reference scenario indicates that by far the largest fraction of the oxidized uranium will reprecipitate within the canister. This may significantly decrease the fuel surface available for oxidation and the water available for radiolysis. Subsequently, much less fuel matrix will be dissolved and much less of the other nuclides will be released. Simulations further identify that carbonate and silicate have the greatest influences on the formation of secondary phases, and on the release of nuclides, under natural repository conditions.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 663: Symposium – Scientific Basis for Nuclear Waste management XXIV , 2000 , 531
Copyright
Copyright © Materials Research Society 2001

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. Shoesmith, D.W. and Sunder, S., SKB TR 91-63 (1991).Google Scholar
2. Werme, L., Sellin, P. and Forsyth, R., SKB TR 90-08 (1990).Google Scholar
3. Sunder, S. and Shoesmith, D.W., AECL-10395, (1991).Google Scholar
4. Forsyth, R., SKB TR 97-25 (1997).Google Scholar
5.SR95, SKB TR 96-05 (1995).Google Scholar
6. Neretnieks, I., Mat. Res. Soc. Symp. Proc., 465, 573–580 (1997).Google Scholar
7. Romero, L., Moreno, L. and Neretnieks, I., Nuclear Technology, 110, No.2; 238–249 (1995).Google Scholar
8. Liu, L. and Neretnieks, I., Mat. Res. Soc. Symp. Proc., 556, 591–598 (2000).Google Scholar
9. Liu, L. and Neretnieks, I., Mat. Res. Soc. Symp. Proc., 556, 1001–1008 (2000).Google Scholar
10. Bond, A.E., Hoch, A.R., Jones, G.D., Tomczyk, A.J., Wiggin, R.M., and Worraker, W.J., SKB TR 97-19 (1997).Google Scholar
11. Bruno, J., Cera, E., Pablo, J.D., Duro, L., Jordana, S. and Savage, D., SKB TR 97-33 (1997).Google Scholar
12. Yu, J. and Neretnieks, I., SKB TR 97-12 (1997).Google Scholar