Development and performance evaluation of Sr2CeO4 - SrCe0.85Y0.15O3-ᴓ based electrochemical hydrogen isotopes sensor.

• Developed an electrochemical based hydrogen isotope sensor using synthesized mixed-phase Sr 2 CeO 4 - SrCe 0.85 Y 0.15 O 3-ᴓ ceramic. • The sensor is tested at different temperatures (400, 450 & 500 °C) with known and fixed calibrated hydrogen concentration in reference and working side. • The sensor exhibited a stable electrochemical potential at 450 & 500 °C and its values were found to be close to the theoretical estimations. One of the most significant fundamental requirement for the Tritium Extraction System (TES) of fusion breeder blanket system with liquid Pb-Li as tritium breeder is an online, quick, accurate, and reliable measurement of hydrogen isotope concentration in liquid lead lithium (Pb-Li). Though Permeation-based hydrogen isotope sensors have been reported for this, they corrode in the presence of liquid Pb-Li. This corrosion greatly lowers the permeation flux and hence the sensor's performance over time. As a result, they may need to be replaced frequently, which is a limitation of permeation-based sensors. Solid state proton conducting ceramics have attracted a significant importance in applications related to hydrogen measurement, transport, fuel cell etc. In order to address the issues in hydrogen concentration measurement associated with permeation-based sensors as well to establish an alternate measurement technique, solid state proton conducting electrolyte-based hydrogen isotope sensors are being proposed in literature. These sensors have good physical and chemical sustainability in liquid Pb-Li at higher temperatures. This work presents the detailed description of the design, fabrication and testing of electrochemical–-based hydrogen isotope sensor using in-house synthesized mixed-phase Sr 2 CeO 4 - SrCe 0.85 Y 0.15 O 3-ᴓ ceramic. The disc shaped pellet of mixed phase Sr 2 CeO 4 - SrCe 0.85 Y 0.15 O 3-ᴓ ceramic is used as a solid electrolyte in the sensor. The sensor is tested at various temperatures (400, 450 & 500 °C) with known and fixed calibrated hydrogen concentration in reference and working side. The sensor exhibited a stable electrochemical potential at 450 & 500 °C, and its values was found to be close to the theoretical estimations using Nernst's equation (deviation up to ∼55 mV). In contrast, the sensor at 400 °C showed the shift in potential throughout the experiment (∼2 h). [ABSTRACT FROM AUTHOR]