Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-29T07:35:21.521Z Has data issue: false hasContentIssue false
  • English
  • Français

Evidence of Radiolytic Oxidation of 241Am in Na+ / Cl− / HCO−3/ CO2−3 Media.

Published online by Cambridge University Press:  01 January 1992

Eric Giffaut  and
Pierre Vitorge
Eric Giffaut
Affiliation:
CEA, Department of Waste Management and Storage, Section of Geochemistry, BP 6, 92265, Fontenay aux Roses cedex, France
Pierre Vitorge
Affiliation:
CEA, Department of Waste Management and Storage, Section of Geochemistry, BP 6, 92265, Fontenay aux Roses cedex, France
Get access

Abstract

This paper examines Americium behaviour in CI− media at room temperature in connection with environmental and waste disposal programs. Most published values on U, Np, Pu and Am complexation in chloride media have been determined using extraction methods. Spectrophotometric techniques are not sensitive enough to prove actinide complexation by chloride, which is confirmed in this paper for Am(III).

Am(OH)3(s), AmOHCO3(s), Am2(CO3)3(s) or NaAm(CO3)2(s) solid phases can control the Am solubility, depending on the chemical conditions of the aqueous phase (usually PCO2). 241Am solubility is here found to be higher in NaCl 4M media than in NaCl 0.1 M (up to 3 orders of magnitude). Addition of a reducing agent (metallic iron) lowers the solubility. After a week, solubilities in NaCl 0.1 M and 4 M are similar. These results are consistent with Am(III) radiolytic oxidation to Am(V), due to cc radiations. Little evidence of Cl− or mixed Cl−-CO2−3 complexes is found in these conditions. In Na+-OH−-Cl− media, 241Am(III) oxidation had also been proposed. Slow kinetics of precipitation could induce experimental uncertainities.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 294: Symposium V – Scientific Basis for Nuclear Waste Management XVI , 1992 , 747
Copyright
Copyright © Materials Research Society 1993

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. Ward, M. and Welch, G. A., J. Inorg. Nucl. Chem. 2 (395–402) 1956.Google Scholar
2. Grenthe, I., Acta Chim. Scandinavica 16 1962.Google Scholar
3. Peppard, T. F., Mason, G. W. and Hucher, I., J. Inorg. Nucl. Chem. 24 (881-888) 1962.Google Scholar
4. Bansal, B. M. L., Patil, S. K. and Sharma, H. D., J. Inorg. Nucl. Chem. 26 (993-1000) 1964.Google Scholar
5. Sekine, T., Acta Chim. Scandinavica 19 (1435-1444) 1965.Google Scholar
6. Khopkar, P. K. and Narayanankutty, P., J. Inorg. Nucl. Chem. 33 (495-502) 1971.Google Scholar
7. Fukasawa, T., Kawasuji, I. and Mitsugashira, T., Bull Chem. Soc. Japan 55 (726-729) 1982.Google Scholar
8. Marcus, Y. and Shiloh, M., Israel J. Chem. 7 (31-43) 1969.Google Scholar
9. Staadler, S. and Kim, J. I., Report RCM 01188 University of Munich 1988.Google Scholar
10. Grenthe, I., Fuger, J., Konings, R., Lemire, R., Muller, A., Nguyen-Trung, C. and Vanner, H., Chemical Thermodynamics of Uranium. OECD. Elsevier Science Ed. 1992.Google Scholar
11. Vitorge, P., Radiochim. Acta, in press, 1992.Google Scholar
12. Robouch, P., Thesis. Louis Pasteur University (Strasbourg. France) 1987 (CEA report R-5473).Google Scholar
13. Maya, L., Inorg. Chem. 22 (2093-2095) 1983.Google Scholar
14. Grenthe, I., Robouch, P. and Vitorge, P., J. Less-Common Metals 122 (225-231) 1986.Google Scholar
15. Riglet, C., Thesis. University of Paris VI, 1989.Google Scholar
16. Magirius, S., Carnall, W. T. and Kim, J. I., Radiochim. Acta 38 (29-32) 1985.Google Scholar