Investigation of The Corrosion Behavior of Metallic Aluminum Embedded in A Cement Matrix

The Belgian Reactor 1 (BR1) is the first Belgian research reactor. Its natural metallic uranium fuel is encapsulated in an aluminum cladding. One solution for the long-term management of these fuels, which will eventually become waste, is geological disposal. To do so, a direct embedding of the waste in a cement-based material could be used. Therefore, the corrosion of the fuel in these conditions (high pH and anaerobic) needs to be studied. In this Master thesis, the corrosion of aluminum cladding was investigated by observing the electrochemical behavior and the H2 gas release when aluminum was embedded in Ordinary Portland Cement (OPC) immersed in limewater under anaerobic conditions. Four different conditions of OPC were tested to study the influence of different porosity, induced by different water-to-cement ratio, and the presence of LiNO3 as corrosion inhibitor. Corrosion rates were calculated by measuring the H2 gas release by gas chromatography and pressure sensors, and by the electrochemical impedance spectroscopy (EIS) response. Corrosion rate ranges from 3 to 168 μm/y after three months of experiment. The lowest results were obtained when a cement with a lower porosity in presence of LiNO3 was used, while the highest corrosion rates were observed when a cement possessing a higher porosity without LiNO3 addition was used. In the conditions studied here, both cement porosity and the presence of a corrosion inhibitor play an important role on the corrosion of embedded aluminum in OPC cement.