Simulated real-time process monitoring of a molten salt electrorefiner

• An alternative approach to safeguarding and monitoring pyroprocessing is proposed.
• Possible signals to be used to monitor an electrorefiner are identified.
• An inverse model was developed to determine deposition rates at the cathode.
• The sensitivity of certain parameters in the inverse model are presented.

An alternative approach to monitoring the pyrochemical process (pyroprocessing) for spent nuclear fuel treatment is proposed and examined. This approach relies on modeling and the real-time analysis of process readings. Using an electrorefiner model, named ERAD, cathode potential and cell current were identified as useful process readings. To provide a real-time analysis of these two process readings, an inverse model was developed based on fundamental electrochemical relations. The model was applied to the following operating modes: pure uranium deposition, co-deposition of uranium and plutonium, and co-deposition of uranium and zirconium. Using the cell current and cathode potential, the model predicted which species were depositing and their rates. The deposition rates predicted by the inverse model compared favorably to those calculated by ERAD.