Testing of high temperature reference electrodes for light water reactor applications

The main objective of the LIRES (light water reactor reference electrodes) project, supported by the EC within the EURATOM FP5, was to develop reference electrodes, which are robust enough to be used inside a light water reactor at temperatures up to 320 °C and pressures up to 120 bar. This contribution summarises the test of three types of reference electrodes developed within LIRES: (i) an external Ag/AgCl reference electrode from the NRI, Rez, Plc, (ii) a PtIr alloy hydrogen electrode from Studsvik Nuclear AB, and (iii) a Pd-hydride reference electrode—Pd(Pt) polarised active electrode pair—from the VTT Technical Research Centre of Finland. Our results are being compared, within a Round Robin test, with similar measurements of a number of laboratories to select the appropriate reference electrodes for long-term tasks, when the potential should be monitored for months under irradiating conditions.