Electrochemical techniques for monitoring dissolved carbon, hydrogen and oxygen in liquid sodium

Preparation, characterization and sintering of yttrium-doped ThO2 for oxygen sensors applications

“…The electrolyte materials were generally based doped ThO2 or ZrO2, with metal/metal oxide or gas acting as reference electrode [7]. As instance, recent researches were conducted on Ca-doped [8] and Y-doped [9] zirconia because of the easier availability of the materials, but the best results were obtained with ThO2-based solid solutions [2,3,[5][6][7][10][11][12][13][14][15][16][17][18]. The majority of the probes produced up to now were designed in 1970's and 1980's, with some of them being tested in reactors [15,17] and made commercially available.…”

“…The yttrium incorporation ratio was usually in the 7.5-15 wt.% Y2O3 range, since the maximum ionic conductivity was reported for an yttrium doping of x = 0.15 [10,18]. However, if lifetimes up to 10 000 hours were reported [11,13] the probes generally suffered from their lack of robustness and reliability. Particularly, an important sensitivity to thermal and mechanical stress was observed and linked to a weakening of the probe both at the brazure level and within the ceramic electrolyte itself [14,16].…”

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

“…However, hydrogen would escape to the argon cover gas plenum of sodium circuits, and hence, by on-line monitoring of hydrogen in cover gas, steam leaks under these conditions can be detected. 2) A diffusion-based hydrogen detection system for this purpose has been developed. It uses a thermal conductivity detector (TCD), whose schematics are shown in Fig.…”

“…in sodium, even at ppm levels, can lead to corrosion and mass transfer in these circuits and cause radioactivity transport from the reactor core to other areas. 2,3) Hence, it is necessary to monitor continuously these impurities in the coolant using reliable sensors. It is also essential to detect any event of leak of high-pressure steam into the sodium coolant circuit at the steam generator using reliable sensors to initiate remedial action.…”

Novel approach for the bulk synthesis of nanocrystalline yttria doped thoria powders via polymeric precursor routes

“…The ionic conductivity of yttria doped thoria (YDT) attains a maximum at 7.5 mol% concentration of Y 2 O 3 while in case of calcia stabilized zirconia (CSZ) this maximum is at 12-13 mol% concentration of CaO [1]. The 7.5 mol% Y 2 O 3 -ThO 2 has been identified as the most suitable electrolyte for monitoring oxygen concentration in liquid sodium coolant of fast reactors [4][5][6][7][8][9]. A solid electrolyte for this application is required as a ceramic body with high density (P 99% th.d.)…”