Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-28T20:17:32.146Z Has data issue: false hasContentIssue false
  • English
  • Français

Influence of Iron(II) and Iron(III) Ions on the Corrosion of MTR Fuel Element Claddings in Repository-Relevant Brines

Published online by Cambridge University Press:  10 February 2011

S. Zschunke  and
J. Fachinger
S. Zschunke
Affiliation:
Forschungszentrum Jülich, 52425 Jülich, Germany, s.zschunke@fz-juelich.de
J. Fachinger
Affiliation:
Forschungszentrum Jülich, 52425 Jülich, Germany, j.fachinger@fz-juelich.de
Get access

Abstract

After the USA decided in 1988 to no longer accept spent fuel elements from German material test reactors (MTR), a national back-end fuel cycle alternative was sought in the Federal Republic of Germany [1]. The aim is their direct final disposal in deep, stable geologic formations. The corrosion of material test reactor (MTR)-fuel element claddings (aluminium) in repository-relevant brines was examined. Before the aluminium cladding material can corrode, the POLLUX cask, containing the fuel elements, must be corroded. In this case, iron(II) and iron(III) ions are present in the brine. These ions decisively influence the corrosion of the MTR fuel element cladding material, therefore the mechanism responsible for this phenomenon should be identified. Tests were performed in which Fe(II) and Fe(III) salts were added to the brines. In these experiments, the percentage mass decrease of the aluminium cladding, the iron content of the brine, as well as the pH value were determined. As expected the results provided the information about the corrosion mechanism. The higher the concentration of iron ions in the brines, the higher the aluminium corrosion rate was for all three brines. Identical redox equilibria between Fe(II) and Fe(III) were formed in the brine, irrespective of whether Fe(II) or Fe(III) salt had been added. It is assumed that the acceleration of the corrosion rate is based on the fact that Fe(II) is reduced to metallic iron by absorbing the electrons produced during the oxidation of aluminium to Al(III). The aluminium cladding material does not function as a barrier for the release of radionuclides from the fuel elements. The results of this study show that the 0.38 mm thick aluminium cladding will corrode through after approximately four weeks.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 506: Symposium – Scientific Basis for Nuclear Waste Management XXI , 1997 , 511
Copyright
Copyright © Materials Research Society 1998

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 Dietrich, M., Brücher, H., Kenntnissstand zum Verhalten der Aluminium-MTR-Brennelemente unter Zwischenlagerbedingungen, Interner Bericht, KFA-ICT-IB-535/92 (März 1993).Google Scholar
2 Brodda, B.-G., Fachinger, J., Corrosion Behaviour of Spent MTR Fuel Elements in a Drowned Salt Mine Repository, Mat. Res. Soc. Symp. Proc., 353, p. 593 (1995).Google Scholar
3 Closs, K.D., Stand der Arbeiten zur direkten Endlagerung in der Bundesrepublik Deutschland, Atomwirtschaft, p. 193–198 (April 1990).Google Scholar
4 Fachinger, J., Rainer, H., Syuhada, I., Investigations of the Behaviour of Aluminiumclad Metallic Material Test Reactor Fuel Elements (MTR-FE) in Concentrated Salt Brines, Jahrestagung Kerntechnik '96, p. 639–642 (1996).Google Scholar
5 Fachinger, J., Brodda, B.-G., Leaching of Radionuclides from MTR-Fuel Elements in Concentrated Salt Brines, Proceedings of the International Topical Meeting on Nuclear and Hazardous Waste Management Spectrum '96, p. 2068–2071 (August 1996).Google Scholar
6 KFA-Spezification, No. 22311/80-HEU-MTR-FRJ-EWR, p. 8.Google Scholar
7 Koch, O.G., Koch-Dedic, G.A., Handbuch der Spurenanalytik, part 2, p. 703, Springer Verlag Berlin-Heidelberg-New York (1974).Google Scholar
8 Clark, L.J., Anal. Chem., 34, S. 348 (1962).Google Scholar
9 Pollock, E.N., Miguel, A.N., Anal. Chem., 39, S. 272 (1967).Google Scholar
10 Rainer, H., Fachinger, J., Sorption of Various Radionuclides on Aluminium Oxide and on Aluminium Corrosion Products under Reducing Saline Conditions, RADWAP '97, 23.06.- 26.06.97, Würzburg, Germany.Google Scholar