A URANIUM CARBIDE/RHENIUM THERMIONIC FUEL ELEMENT

A THERMIONIC FUEL ELEMENT (TFE) BASED ON ADVANCED URANIUM CARBIDE (UC) SOLID SOLUTION FUEL WITH RHENIUM EMITTER CLADDING SHOULD ALLOW MUCH BETTER PERFORMANCE THAN PRESENT DESIGNS. THE FUEL FORM WOULD BE A LONG, THIN, HOLLOW "VERMICELLI" SHAPE TO ALLOW VERY COMPACT REACTORS TO BE DESIGNED, DESPITE THE HIGH NEUTRON ABSORPTION CROSS SECTION OF RHENIUM. RHENIUM IS EXPECTED TO BE COMPLETELY COMPATIBLE WITH CARBIDE FUEL. IN PHASE I, A CARBIDE-FUELED TFE WILL BE DESIGNED, SUITABLE FOR SPACE NUCLEAR POWER SUPPLIES. DATA OBTAINED FROM RUSSIAN PROGRAMS, IN WHICH A UC:TAC (TANTALUM CARBIDE) ELEMENT WAS FABRICATED AND TESTED IN A REACTOR AT SVERDLOVSK, WILL BE USED IN THE DESIGN. BOTH MULTICRYSTAL RHENIUM AND SINGLE CRYSTAL TUNGSTEN WILL BE INCORPORATED INTO THE DESIGNS AS EMITTER OR CLADDING MATERIALS.