Evaluation of the corrosion rate and mechanism of metallic uranium (BR1 fuel) in highly alkaline and anaerobic conditions

At SCK CEN, natural unalloyed metallic uranium, encapsulated in an aluminium container, is used as nuclear fuel in the BR1. One solution for the long-term waste management of this fuel is geological disposal. A potential route entails the mechanical removal of the aluminium container followed by the direct embedding of the metallic uranium in a cement-based material. In contact with the highly alkaline cement-equilibrated pore water, a high corrosion rate of metallic uranium could be expected, going along with the formation of uranium oxides, hydrides, and hydrogen gas, which could induce different problematic processes that are mainly related to the generation of stresses. However, if a cement-based embedding material with a low porosity is used, the diffusion of water and reaction products through the material will be limited, which is expected to result in a drastic decrease of the corrosion rate. To evaluate this option implies (i) to characterise the metallic uranium coming from BR1, (ii) to study the metallic uranium corrosion in highly alkaline solutions, (iii) to study the electrochemical behaviour of the metallic uranium in highly alkaline solutions, (iv) to study the influence of the limited mass transfer by encapsulating the metallic uranium in cementitious grouts possessing different porosity.

At the end of this PhD topic, participation to at least two international scientific conferences and the publication of two scientific papers is needed.

The minimum diploma level of the candidate needs to be

• Master of sciences
• Master of sciences in engineering

The candidate needs to have a background in

• Chemistry
• Corrosion

Estimated duration

Expert group