Spent nuclear fuel is processed to recover uranium and plutonium. This generates radioactive waste, such as contaminated sodium carbonate solutions used in washing steps. The residual plutonium in such waste solutions needs to be removed before they are disposed of. Usually, this requires acidification as a first step, which increases the volume of the waste. Electrochemical processes could provide a useful alternative approach that avoids this extra waste.
Santu Kaity, Bhabha Atomic Research Centre, Mumbai, India, and colleagues have developed a simple two-step process for the recovery of Pu as solid PuO2 powder from carbonate waste solutions. The team first electrochemically precipitated Pu as plutonium hydroxide by bulk electrolysis at –0.9 V using a Pt electrode. This process is selective and can be used on real carbonate waste that contains other, potentially interfering elements (U, Th, Ru, Zr, Nb, Cs) and degradation products that stem from the processing of the spent nuclear fuel.
In a second step, the precipitate was calcined at 973 K to convert it to PuO2 powder. The developed approach avoids the formation of secondary waste and prevents the pollution of aquatic environments.
- Electrochemical Recovery of Plutonium from Aqueous Carbonate Waste Solutions,
Rahul Agarwal, Rama Mohana Rao Dumpala, Manoj Kumar Sharma, Donald M. Noronha, Jayashree S. Gamare, Kavita Jayachandran, Chiranjit Nandi, Santu Kaity,
Chem. Commun. 2022.