Hostname: page-component-586b7cd67f-rcrh6 Total loading time: 0 Render date: 2024-11-29T07:43:05.505Z Has data issue: false hasContentIssue false

Kinetics of UO2 (s) Dissolution in the Presence of Hypochlorite, Chlorite, and Chlorate Solutions

Published online by Cambridge University Press:  01 February 2011

Rosa Sureda
Affiliation:
Dept. Chemical Engineering, Universitat Politécnica de Catalunya, Avda. Diagonal 647, 08028 Barcelona, Spain
Ignasi Casas
Affiliation:
Dept. Chemical Engineering, Universitat Politécnica de Catalunya, Avda. Diagonal 647, 08028 Barcelona, Spain
Javier Giménez
Affiliation:
Dept. Chemical Engineering, Universitat Politécnica de Catalunya, Avda. Diagonal 647, 08028 Barcelona, Spain
Joan de Pablo
Affiliation:
Dept. Chemical Engineering, Universitat Politécnica de Catalunya, Avda. Diagonal 647, 08028 Barcelona, Spain Environmental Technology Area-CTM Centre Tecnológic, Avda. Bases de Manresa 1, 08242 Manresa, Spain
Get access

Abstract

The influence of hypochlorite, chlorite and chlorate in the UO2 dissolution rate has been studied experimentally using a continuous flow-through reactor. Uranium concentration in each outflow solution was measured as a function of time and dissolution rates were determined once the steady-state was reached. The results obtained show that the influence of the hypochlorite anion concentration on the UO2 dissolution rate can be expressed by the following empirical equation

rdiss = 10-8.7±0.1•[ClO-]0.28±0.04

The dissolution rates obtained in this work were higher than those previously determined in presence of either oxygen or hydrogen peroxide using the same experimental methodology.

In contrast, neither chlorate nor chlorite had any significant effect on the UO2 dissolution rates under the experimental conditions of this work.

Type
Research Article
Copyright
Copyright © Materials Research Society 2008

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

1 Gray, W.J. and Wilson, C.N., Spent fuel dissolution studies: FY 1991 to 1994. Report PNL-10540, USA (1995).Google Scholar
2 Shoesmith, D.W., Fuel corrosion processes under waste disposal conditions, J. Nucl. Mater. 282 (2000) 131.Google Scholar
3 Torrero, M.E., Baraj, E., Pablo, J. de, Giménez, J. and Casas, I., Kinetics of corrosion and dissolution of uranium dioxide as a function of pH, Int. J. Chem. Kinet. 29 (1997) 261267.Google Scholar
4 Pablo, J. de, Casas, I., Giménez, J., Molera, M., Rovira, M., Duro, L. and Bruno, J., The oxidative dissolution mechanism of uranium dioxide. I. The effect of temperature in hydrogen carbonate medium, Geochim. et Cosmochim. Acta 63 (1999) 30973103.Google Scholar
5 Pablo, J. de, Casas, I., Giménez, J., Clarens, F., Duro, L. and Bruno, J., The oxidative dissolution mechanism of uranium dioxide. The effect of pH and oxygen partial pressure, Mater. Res. Soc. Symp. Proc. 807 (2004) 8388.Google Scholar
6 Giménez, J., Clarens, F., Casas, I., Rovira, M., Pablo, J. de, Bruno, J., Oxidation and dissolution of UO2 in bicarbonate media: Implications for the spent nuclear fuel oxidative dissolution mechanism, J. Nucl. Mater. 345 (2005) 232238.Google Scholar
7 Hiskey, J.B., Kinetics of uranium dioxide dissolution in carbonate solutions, Trans. Inst. Min. Metall. Sect. C 89 (1980) 145171.Google Scholar
8 Shoesmith, D.W. and Sunder, S., The prediction of nuclear fuel (UO2) dissolution rates under waste disposal conditions, J. Nucl. Mater. 190 (1992) 2035.Google Scholar
9 Giménez, J., Baraj, E., Torrero, M.E., Casas, I. and Pablo, J. de, Effect of H2O2, NaClO and Fe on the dissolution of unirradiated UO2 in NaCl 5 mol kg-1. Comparison with spent fuel dissolution experiments, J. Nucl. Mater. 238 (1996) 6469.Google Scholar
10 Ekeroth, E. and Jonsson, M., Dissolution of UO2 by radiolytic oxidants, J. Nucl. Mater. 322 (2003) 242248.Google Scholar
11 Clarens, F., Pablo, J. de, Casas, I., Giménez, J., Rovira, M., Merino, J., Cera, E., Bruno, J., Quiñones, J., Martínez-Esparza, A., The oxidative dissolution of unirradiated UO2 by hydrogen peroxide as a function of pH, J. Nucl. Mater. 345 (2005) 225231.Google Scholar
12 Gray, W.J., Effects of radiation on the oxidation potential of salt brine, Mater. Res. Soc. Symp. Proc. 112 (1988) 405413.Google Scholar
13 Kelm, M., Bohnert, E., Gamma radiolysis of NaCl brine: Effect of dissolved radiolysis gases on the radiolytic yield of long-lived products, J. Nucl. Mater. 346 (2005) 14.Google Scholar
14 Büppelmann, K., Magirius, S., Lierse, Ch., Kim, J.I., Radiolytic oxidation of americium(III) to americium(V) and plutonium(IV) to plutonium(VI) in saline solution, J. Less-Common Metals 122 (1986) 329336.Google Scholar
15 Büppelmann, K., Kim, J.I., Lierse, Ch., The redox-behaviour of plutonium in saline solutions under radiolysis effects, Radiochim. Acta 44/45 (1988) 6570.Google Scholar
16 Kelm, M., Pashalidis, I., Kim, J.I., Spectroscopic investigation on the formation of hypochlorite by alpha radiolysis in concentrated NaCl solutions, Appl. Radiat. Isotopes 51 (1999) 637642.Google Scholar
17 Hartmann, Th., Paviet-Hartmann, P., Wetteland, Ch., Lu, N., Spectroscopic determination of hypochlorous acid, in chloride brine solutions, featuring 5 MeV proton beam line experiments, Radiat. Phys. Chem. 66 (2003) 335341.Google Scholar
18 Kim, W.H., Choi, K.C., Park, K.K., Eom, T.Y., Effects of hypochlorite ion on the solubility of amorphous schoepite at 25°C in neutral to alkaline aqueous solutions, Radiochim. Acta 66/67 (1994) 4549.Google Scholar
19 Ershow, B.G., Kelm, M., Janata, E., Gordeev, A.V., Bohnert, E., Radiation-chemical effects in the near-field of a final disposal site: role of bromine on the radiolytic processes in NaCl-solutions, Radiochim. Acta 90 (2002) 617622.Google Scholar
20 Kelm, M., Bohnert, E., Radiation chemical effects in the near field of a final disposal site – I: Radiolytic products formed in concentrated NaCl solutions, Nucl. Technol. 129 (2000) 119122.Google Scholar
21 Kelm, M., Bohnert, E., Radiation chemical effects in the near field of a final disposal site –II: Simulation of the radiolytic processes in concentrated NaCl solutions, Nucl. Technol. 129 (2000) 123130.Google Scholar
22 Giménez, J., Clarens, F., Casas, I., Rovira, M., Pablo, J. de, Bruno, J., Oxidation and dissolution of UO2 in bicarbonate media: Implications for the spent nuclear fuel oxidative dissolution mechanism. J. Nucl. Mater. 345 (2005) 232238.Google Scholar
23 Torrero, M.E., Baraj, E., Pablo, J. de, Giménez, J., Casas, I., Kinetics of corrosion and dissolution of uranium dioxide as a function of pH. Int. J. Chem. Kinet. 29 (1997) 261267.Google Scholar
24 Clarens, F., Pablo, J. de, Casas, I., Giménez, J., Rovira, M., Merino, J., Cera, E., Bruno, J., Quiñones, J., Martínez-Esparza, A., The oxidative dissolution of unirradiated UO2 by hydrogen peroxide as a function of pH. J. Nucl. Mater. 345 (2005) 225231.Google Scholar