Behaviour of reference electrodes in the monitoring of corrosion potential at high temperature

The main problem of corrosion potential measurements is the necessity to develop a reliable high temperature reference electrode. The aim of this work was to study the behaviour of three types of high temperature reference electrodes that have been developed for use in a BWR type reactor operating conditions. The reference electrodes were copper/copper(I) oxide with yttria-stabilized zirconia (YSZ) membrane; a silver/silver chloride couple and platinum. The application of these electrodes to corrosion potential monitoring is illustrated with several examples in different environments. The thermodynamic behaviour and stability of these sensors have been studied. Correlations between corrosion potential and water chemistry have been determined. (orig.)