Development of an electrochemical lithium sensor for Pb-17Li

Within the framework of the European Fusion Technology Program an electrochemical lithium probe has been developed at SCK/CEN Mol, Belgium. The results of several tests runs with a Na-β-alumina based sensor in a static system are described. An exposure test of more than 3000 hours in Pb-17Li was performed in order to demonstrate the compatibility of the solid electrolyte with the liquid metal environment. Other long term tests, with several sensors exposed consecutively to different lithium-lead compositions at the same temperature (723 K), have shown a fast response to lithium concentration variations and emf values, which are in accordance with lithium activity data reported by other authors. Prototype lithium as well as oxygen sensors have been constructed and exposed in a thermal convection loop at different temperatures. Preliminary lithium activity data obtained in such a dynamic system are reported and compared with data obtained in the static test campaigns