Lifetime changes in the characteristics of thermionic converters

The substantiation of the lifetime stability of the emission properties of electrodes and electric characteristics of the electricity-generating channel (EGC) and element (EGE) of a space thermionic nuclear power system for an operating period of 5-10 or more years is examined. The basic reasons for the changes in the emission properties of EGE/EGC electrodes and a Topaz type reactor-converter are analyzed on the basis of test data and data from experimental simulation of the working processes in the interelectrode medium. A scheme is proposed for the working process occurring in the interelectrode medium of the EGE; the scheme is based on the Topaz materials and technology. The stability of the emission characteristics of electrodes with the respect to possible changes during prolonged operation is analyzed for the most advanced designs of space nuclear power systems. The changes in time and the corresponding changes in the output electrical characteristics are estimated. 36 references.