Citrate, a common salt found in nature, is widely used to clean up radioactive materials in the nuclear industry. It's also present in low-level radioactive waste. When combined with certain elements (including radioactive substances), citrate has the potential to cause the contaminants to be released into the environment. Understanding how citrate undergoes biodegradation in the presence of these elements is crucial to predict the impact it might have on radioactive waste and to ensure the safe disposal of this waste.
Researchers from Nuclear Waste Services and the Universities of Manchester and Sheffield, conducted experiments at Diamond where they mixed citrate with nickel and uranium (specifically Ni2+ and U(VI)O22+) under conditions that resemble those in which low-level radioactive waste is managed. They used X-ray Absorption Spectroscopy (XAS) and Extended X-ray Absorption Fine Structure (EXAFS) techniques to study how citrate interacts with these metals and whether it breaks down over time. Additionally, they examined the types of bacteria that were involved in breaking down citrate and how they interacted with these metals under these specific conditions. The main goal was to gain a better understanding of how citrate and metals behave in situations related to the storage and safe disposal of radioactive waste.