DEVELOPMENT AND COMPARISON OF A TOPAZ-II SYSTEM MODEL WITH EXPERIMENTAL-DATA

An integrated model of the TOPAZ-II space nuclear reactor system is de veloped and compared with measurements from the TOPAZ-II, V-71 unit te sts. For a given reactor thermal power, the model calculates the coola nt flow rate, temperature, and pressure throughout the system; load el ectric power; and overall system efficiency. Model predictions showed good agreement with the experimental data. The calculated coolant temp eratures and pressure are within 15 K (<2 %) and 12% of the measuremen ts, respectively. Analysis showed that at the nominal operating therma l power of the system (115 kW), the NaK coolant is highly subcooled. T he largest subcooling of 365 K occurs at the exist of the electromagne tic pump, where coolant pressure is highest, and the lowest subcooling of 275 K occurs at the exit of the reactor core, where coolant temper ature is highest.