SORPTION RESERVOIRS FOR THERMIONIC CONVERTERS

THERMIONIC ENERGY CONVERTERS, AS THEY NOW EXIST, ARE THREE-TEMPERATURE DEVICES: INPUT (EMITTER), OUTPUT (COLLECTOR) AND CESIUM RESERVOIR. THE RESERVOIR REQUIRES PRECISE CONTROL AT A TEMPERATURE ON THE ORDER OF 600K. A SEPARATE RESERVOIR IS REQUIRED FOR EACH CONVERTER OR THERMIONIC FUEL ELEMENT. THE COMPLEXITY ARISING FROM THE RESERVOIR CONTROL PROBLEM IS SUFFICIENT TO DISQUALIFY THERMIONIC SYSTEMS IN SOME INSTANCES. IN THIS PROGRAM, AN INTERNAL SELF-CONTROLLING CESIUM RESERVOIR IS BEING DEVELOPED, MAKING THE THERMIONIC CONVERTER A TRUE TWO-TEMPERATURE DEVICE. PREVIOUS WORK HAS IDENTIFIED AT LEAST TWO TYPES OF RESERVOIRS USING SORPTION PRINCIPLES. EACH HAS LIFE LIMITING FAILURE MECHANISMS. THIS TECHNICAL APPROACH IS EXPECTED TO ELIMINATE THESE FAILURE MECHANISMS, YIELDING A RELIABLE, LONG-LIVED CONVERTER. WHEN SUCCESSFUL,THE USE OF THERMIONIC CONVERSION WOULD BE GREATLY SIMPLIFIED. THIS SIMPLIFICATION IS EXPECTED TO MAKE THERMIONIC CONVERSION PRACTICAL FOR USE IN SPACE POWER PLANTS AND POTENTIALLY FOR LUNAR AND PLANETARY BASES.