Development of Sensors for On-Line Monitoring of Nonmetallic Impurities in Liquid Sodium

Abstract

Sensors for on-line monitoring of hydrogen and carbon in sodium and hydrogen in argon cover gas circuits over sodium have been developed. The performance of these sensors in fast breeder test reactor (FBTR) and large sodium facilities is evaluated. A sensor for monitoring oxygen in sodium is under development. The in-sodium electrochemical hydrogen sensors are found to detect about 10 ppb increase in hydrogen concentration over a background of 50 ppb. The cover gas hydrogen monitoring sensor system is found to sense hydrogen down to 2 vppm in argon over sodium systems. Electrochemical carbon sensors are capable of detecting down to 1 ppm of carbon in sodium.

Review—Evolution of the Development of In-Sodium Oxygen Sensor and Its Present Status

“…3c) with In/In 2 O 3 as reference electrode and tested in static sodium. These sensors showed near theoretical output corresponding to oxygen concentration in sodium at 723 K. 53 However, their lifetimes varied between 24 and 720 h and the failure was observed at the metal-ceramic interface region. This suggested that probably stress prevailed at the interface, which led to the failure of the ceramic.…”

HfO2-based electrolyte potentiometric oxygen sensors for liquid sodium

“…The state-of-the-art yttria-doped thoria (YDT) electrolyte fulfills the chemical stability requirements in a sodium environment [8][9][10][11][12][13][14][15][16][17][18]. However, the solid electrolyte exhibits many drawbacks: it is a nuclear material, this oxide is difficult to supply, it is very expensive [19], the conventional sintering method requires temperatures of higher than 2000°C and the material's mechanical resistance is poor.…”