Abstract
An investigation into sources of inconsistencies in sodium exposure test cell (SETC) measurements, used to characterize AMTEC electrode performance, was conducted. Development of modifications to the SETC setup and operation was also accomplished. Potential sources of inconsistencies in SETC measurements were identified through a review of the literature and consultations with the AMTEC community. Due to the complex inter-relations among the potential sources of inconsistencies, the possibilities were narrowed to a few whose effects could be isolated. Modifications to the SETC, made to isolate the individual sources, resulted in more accurate SETC measurements. Preliminary testing showed that sodium containment affected the calculation of the normalized exchange current density and the apparent charge transfer resistance and their relationship to sodium pressure and temperature. The proper electrode area definition was determined by comparing 2-probe and 3-probe test configuration data. Results indicated an inaccurate use of electrode area in the 2-probe electrochemical testing configuration. The new testing configuration utilizing a separate reference electrode, designated the (a-probe configuration, allowed separation of cathodic and anodic effects at the electrode. Electrochemical theory was applied to explain the SETC performance resulting from the modifications to the setup and operation. It was concluded from the findings in this work that sodium pool containment and electrode area definition are sources of inconsistencies in quantities measured in an SETC and that the 3-probe configuration along with sodium containment offers a more specific measure of AMTEC electrode performance.
Fiebig, Bradley Nelson (1999). Development of an improved sodium exposure test cell experiment for characterization of AMTEC electrode performance. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1999 -THESIS -F5.