Thermionic conversion performance analysis of the single-cell thermionic fuel element based on FROBA-THERMION code

The thermionic conversion performance of the single-cell thermionic fuel element (TFE) is influenced by fuel mass transfer and other parameters. With the consideration of current flow and heat transfer, the thermionic conversion model and the modified heat transfer model were implemented in FROBA-THERMION, a steady-state performance analysis code for the single-cell TFE. Afterward, both implemented models were verified by comparing with experiments or calculation results of KATET (a complex code developed by the Research Inst of SIA 'Lutch' of Russia to simulate single-cell TFE life behavior). Further, a steady-state performance simulation of the single-cell TFE was carried out. The results indicate that the thermionic conversion efficiency will be decreased due to the emitter temperature flattening caused by fuel mass transfer. In addition, the influence of several key parameters on thermionic conversion efficiency and measures to improve the thermionic conversion efficiency were analyzed.