FIELD: electric power plants, in particular, using heat-emission reactor converting heat directly into electric power. SUBSTANCE: reactor testing of heat-emission power-generating assemblies involves gas-tight splitting chamber of heat-emission power-generating assemblies and source of cesium vapor from pumping system by means of sealing device; measuring temperature of jackets of heat-emission power-generating assemblies, periodic pumping inter-electrode spaces in heat-emission power-generating assemblies by opening-closing sealing device under stepped-down cesium vapor pressure, testing gas-tightness of sealing device by supplying neutral gas from side of pumping system; detection of gas leaks in sealing device for short-term temperature increase after gas supply. In case, if sealing device is not gas-tight, goal of invention is achieved by increasing cesium vapor pressure up to normal level, decreasing pressure of neutral gas down to value which is equal to normal pressure of cesium vapor, continuation of testing under continuous supply of neutral gas into chamber from side of pumping system under pressure, which is equal to normal pressure of cesium vapor. EFFECT: possibility to continue testing after detection of gas leaking in valve or another sealing device. 2 dwg
