Abstract
The corrosion performance of Aluminium (Al) and zinc (Zn) is of interest in repositories for radioactive waste as the production of hydrogen gas during their anoxic corrosion may create open pathways for the transport of radioactive ions. Al and Zn rods were embedded in concrete cylinders and immersed in artificial groundwater at anaerobic conditions for 2 weeks and up to 2 years in laboratory conditions. Corrosion rates were determined to enable predictions and estimations of risks for gas evolution and the assessment of the potential impact of corrosion on the structural integrity of concrete in the final repository of low and intermediate level metal-containing waste from dismantled nuclear power plants. Samples were collected after 2, 4, 12, 26, 52 and 104 weeks. The observed corrosion rates were higher for Al compared with Zn, as expected, but both materials revealed comparatively high initial corrosion rates that decreased with time, reaching steady state after 26–52 weeks. Some of the Al containing concrete cylinders were cracked as a result of the corrosion processes after 2 years of exposure, thereby providing free passage between the embedded metal and the surrounding environment. No such effects were observed for Zn. Comparative studies were performed on non-concrete-embedded Al and Zn immersed in artificial groundwater. Observed long-term corrosion rates (1–2 years) were similar to corresponding corrosion rates in concrete. The results indicate that immersion studies in artificial groundwater can be used to estimate the long-term corrosion performance of Zn and Al in concrete.
Highlights
Cracking of the concrete caused by hydrogen evolution from corroding metals like aluminium (Al) and zinc (Zn) at anaerobic conditions would open pathways for radioactive metal ions and particles to be transported from the repository into e.g., the groundwater
Bubbles were observed on the surface of the Al containing concrete cylinders within
Such dispersion may be enabled if the structural integrity of the concrete is compromised
Summary
Dismantling of nuclear power plants will result in a large volume of low and intermediate active waste that needs to be stored safely in a final repository. Concrete is used to contain the potentially active waste and hinder and delay radioactive species being environmentally released and is intended to last for at least 10,000 years. The long service life requested does put high demands on the concrete and its properties to withstand both natural degradation and the influence of the materials stored within. Cracking of the concrete caused by hydrogen evolution from corroding metals like aluminium (Al) and zinc (Zn) at anaerobic conditions would open pathways for radioactive metal ions and particles to be transported from the repository into e.g., the groundwater.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
