Production and optimization of an UO2 electrode by electrodeposition to perform corrosion studies in hyper-alkaline conditions with calcium and silicium electrolytes
The nuclear waste generated due to the production of electricity is confined into isolated repositories. Because of the use of cement in the isolation barriers and also its use as sealing material, it is important to study the effect of cementitious waters in contact with the spent fuel, since these...
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| Tipo de recurso: | tesis de maestría |
| Fecha de publicación: | 2017 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/114991 |
| Acceso en línea: | https://hdl.handle.net/2117/114991 |
| Access Level: | acceso abierto |
| Palabra clave: | Radioactive wastes Calcium Residus radioactius Calci Àrees temàtiques de la UPC::Enginyeria civil::Materials i estructures |
| Sumario: | The nuclear waste generated due to the production of electricity is confined into isolated repositories. Because of the use of cement in the isolation barriers and also its use as sealing material, it is important to study the effect of cementitious waters in contact with the spent fuel, since these materials might play an important role as physical and chemical barriers to the release of radionuclides into the far field. A review of the UO2 electrodeposition process was done to modify commercial electrodes (Dropsens), subsequently to perform electrochemical experiments and therefore understand the behavior of fuel matrix in hyper-alkaline conditions, with Ca and Si dissolutions. Two deposition times were used, 15-min and 60-min; the most reproducible results were shown by the 60-min electrodeposited electrode and this was used for the rest of the experiments. Following this, cyclic-voltammograms were recorded using three types of electrolytes: Na+Cl- 0,1 M; Na+Cl- 0,1 M, SiO3 -2 0,001M; Na+Cl- 0,1 M, SiO3 -2 0,001M and Ca2+ 0,0001 M, all with pH=12. Potentiostatic and corrosion potential experiments were performed to determine the effect of the Ca and Si ions in the oxidation process. The CVS showed six defined regions where oxidation and reduction process occurred; the potentiostatics results revealed the highest current density was obtained for SiO3 -2 and Ca2+, SiO3 -2 , and the lowest current density was obtained for Na+Cl- . The corrosion potential value obtained for Na+Cl- was 42 mV, 40 mV for SiO3 -2 and -2 mV for SiO3 -2 , Ca2+. These results exhibit that both ions reinforce the formation of protective corrosion products on the surface electrode, working as inhibitors and/or blocking the fuel corrosion process. |
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