Sc-doped CaZrO3 hydrogen sensor for liquid blanket system

The control of tritium is essential for the performance of liquid blankets of fusion reactors. On-line hydrogen (isotopes) measurement is a key technology. The on-line hydrogen sensor made of proton conducting ceramics, CaZr0.95O3−aSc0.05, was designed to be used in reducible condition such as liquid blanket system. The CaZrO3 doped with Sc2O3 has higher chemical stability than those with the other dopant oxides such as In2O3 or Ga2O3. The evaluation of the expected performance of the sensor in molten salt LiF–BeF2 (Flibe), liquid metal lithium (Li) and lead–17 lithium (Pb–17Li) was carried out by means of the performance test in gas atmosphere at 700 °C with hydrogen partial pressures equivalent to those for the melts. The sensor performance in liquid metal with low oxygen potential was investigated by means of the test in molten Al. The sensor exhibited stable output and fast response when the hydrogen concentration in the gas or molten aluminum was changed.