Analysis of thermal self-maintained oscillation mechanism in the thermionic reactor-converter with multielement TFE's

The thermal self-maintained oscillation mechanism in the thermionic reactor-converter with multielement thermionic fuel elements (TFEs) is examined in order to determine possible unfavorable results. It is shown that heat transfer unevenness in the reactor with a liquid metal coolant may be the cause of core's thermal instability. Thermal self-maintained oscillations are caused by short-duration periodical boiling of small portions of the coolant in the tight places of the separate channels. The oscillation generation mechanism is outwardly similar to that of natural geysers. Although these results were obtained for thermionic-type reactors, the main phenomena caused by heat transfer nonuniformities may exist in any reactor with a similar fuel element cooling scheme. 6 refs