Active Electrode for Measuring Lanthanide Ion Concentrations in Molten Chloride Salt
Reactors

The concentration of Lanthanide ions needs to be monitored to successfully operate a molten salt reactor because of their high neutron absorption cross-section. One method for monitoring the concentration of lanthanide ions in molten salt is the electrochemical method which can be operated in high-temperature and high-radiation environments. However, in NaCl-MgCl2-UCl3 salt, the lanthanide elements cannot be electrochemically monitored by an inert working electrode due to the magnesium ion reduction potential being higher than that of the lanthanide ions. To measure lanthanide ions with the electrochemical method, an active electrode (aluminum) was used. Various voltammetry techniques and anodic stripping analysis were used to measure lanthanide ions in NaCl-MgCl2 eutectic salt. Using an aluminum working electrode, we are able to measure lanthanide ions in a narrow electrochemical window of NaCl-MgCl2 eutectic salt because lanthanide ions form intermetallic compounds with aluminum.