Hostname: page-component-848d4c4894-mwx4w Total loading time: 0 Render date: 2024-06-23T19:22:55.063Z Has data issue: false hasContentIssue false

Development and application of knowledge-based source-term models for radionuclide mobilisation from contaminated concrete

Published online by Cambridge University Press:  21 March 2011

Guido Deissmann
Affiliation:
Brenk Systemplanung GmbH, Aachen, Germany
Adrian Bath
Affiliation:
Intellisci Ltd, Loughborough, UK
Stephan Jefferis
Affiliation:
Environmental Geotechnics Ltd, Bicester, UK
Stefan Thierfeldt
Affiliation:
Brenk Systemplanung GmbH, Aachen, Germany
Stefan Wörlen
Affiliation:
Brenk Systemplanung GmbH, Aachen, Germany
Get access

Abstract

Concrete materials in nuclear facilities may become activated or contaminated by various radionuclides through different mechanisms. Consequently, decommissioning and dismantling of these facilities produce considerable quantities of these materials (e.g. concrete structures, rubble), which are at least potentially contaminated with radionuclides and which must be managed safely and cost-effectively. In this paper, we present results from a research project that aims at the development of source-term models for the mobilization of radionuclides from contaminated concrete. The objective of this task was to clarify whether a more realistic source-term description could be beneficial for optimization of the management of decommissioning wastes by reducing the amount of material for disposal as radioactive waste as well as by saving natural resources due to the recycling of building materials.

To identify important parameters and processes that affect the release rates of radionuclides, we evaluated the chemical behavior and the solid speciation of radionuclides in concrete materials and the influence of factors like concrete properties, source/pathway of contamination, and the scenario-specific chemical environment and hydraulic regime. Furthermore, concrete degradation processes and their influence on contaminant mobilization were addressed. On this basis, source-term models were developed to describe the radionuclide release by (i) the dissolution of radionuclide containing solid phases, (ii) the desorption of radionuclides from surfaces, and/or (iii) the leaching of radionuclides from a solid matrix without disrupting its structure. These source-term models were parameterized for probabilistic simulations of various release options, including the reuse of recycled building materials, the disposal of rubble in inert and municipal landfills as well as the on-site disposal of concrete materials (e.g. foundations remaining in the ground, in situ burial of rubble). For some scenarios and radionuclides, the calculated release rates were between one and two orders of magnitude lower than those used in former generic calculations. Based on the results of stochastic simulations, the consequences of the use of a more realistic source-term for dose assessments with respect to clearance/recycling of contaminated concrete will be illustrated and discussed.

Type
Research Article
Copyright
Copyright © Materials Research Society 2006

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. Deckert, A., Thierfeldt, S., Kugeler, E. and Neuhaus, I., “Definition of clearance levels for the release of radioactively contaminated buildings and building rubble”, European Commission RP 114, Final report - Contract No C1/ETU/970040, 85 p. (1999).Google Scholar
2. Taylor, H.F.W., “Cement chemistry”, Thomas Telford Publishing, London, 459 p. (1997).Google Scholar
3. Glasser, F.P., J. Hazardous Materials 52, 151 (1997).Google Scholar
4. Albinsson, Y., Andersson, K., Börjesson, S. and Allard, B., J. Contaminant Hydrology 21, 189 (1996).Google Scholar
5. Scheidegger, A.M., Wieland, E., Scheinost, A.C., Dähn, R. and Spieler, P., Environ. Sci. Technol. 34, 4545 (2000).Google Scholar
6. Glasser, F.P., Mineralogical Magazine 65, 621 (2001).Google Scholar
7. Heath, T., Ilett, D.J. and Tweed, C.J., Mat. Res. Soc. Symp. Proc. 412, 443 (1996).Google Scholar
8. Viallis-Terisse, H., Nonat, A., Petit, J.C., Landesman, C. and Richet, C., Radiochim. Acta 90, 699 (2002).Google Scholar
9. Bath, A., Deissmann, G. and Jefferis, S. “Radioactive contamination of concrete: Uptake and release of radionuclides”, Proceed. ICEM ‘03: The 9th International Conference on Radioactive Waste Management and Environmental Remediation, Oxford (2003).Google Scholar
10. Baker, P.G. and Bishop, P.L.,J. Hazardous Materials 52, 311 (1997).Google Scholar
11. Raptis, K., Fleischer, K., Herold, G., Knappik, R. and Müller, H.S., “Penetration behaviour of relevant nuclides in concrete”, Proceed. KONTEC 2003, 6th International Symposium Conditioning of Radioactive Operational and Decommissioning Wastes, Berlin (2003).Google Scholar
12. Fleischer, K., Herold, G., Raptis, K., Neumann, A., H.S. Müller and Knappik, R., “Penetration and leaching studies of radionuclides in concrete and hardened cement paste”, Proceed. NRC-6, 6th International Conference on Nuclear and Radiochemistry, Aachen (2004).Google Scholar
13. “Council directive 1999/31/EC of 26 April 1999 on the landfill of waste”, Official Journal of the European Communities L 182/1, (1999).Google Scholar
14. “Verordnung über den Schutz vor Schäden durch ionisierende Strahlen (Strahlenschutzverordnung - StrlSchV) vom 20. Juli 2001” (German Radiation Protection Ordinance) BGBl. I, 1714 (2001).Google Scholar