Seals thermal cycling stability

Chou, Y.S., Thomsen, E.C., Williams, R.T., Choi, J.P., Canfield, N.L., Bonnett, J.E., Stevenson, J.W., Shyam, A., and Lara-Curzio, E. (2011) Compliant alkali silicate sealing glass for solid oxide fuel cell applications thermal cycle Stability and chemical compatibility. J. Power Sources, 196, 2709-2716. 

Fig. 6.12 Thermal cycle stability of SCN-1 glass seal at 850°C (seal between ceramic bilayers and aluminised SS441 substrate, and contained between two concentric YSZ rings) (Chou and CO workers 2011)...

Mechanical stability against thermal cycling between ambient temperature and Top requires matching of thermal-expansion coefficients of the electrolyte and electrodes, the interconnects, and the seals. Note Ceramic strength is improved where cell design retains the ceramic membrane under a compressive stress. 

For the combined EDS-batch SCWO, a variety of technical issues must be addressed the choice of materials of construction, the method used to introduce oxidant into the vessel, the durability of seals, the stability of SCWO reactions in a large-diameter vessel, the methods used to heat the vessel, the possibility of scaling and corrosion under batch SCWO conditions (salts are proposed to be captured in apan placed in the vessel, but this has not yet been demonstrated), the method used to fabricate the vessel (e.g., single forging vs. welded sections), the impact of repeated explosions followed by thermal and pressure cycles on the integrity of the EDS vessel and SCWO reactor (e.g., crack propagation), the most appropriate method of cooldown and depressurization following munition destruction, and the disposition of process residuals. 

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