POWER SYSTEM-

THIS PROJECT WILL INVESTIGATE THE FEASIBILITY OF A PAS- SIVE-PUMPED RANKINE CYCLE POWER GENERATOR SUITABLE FOR USE IN A SPACE NUCLEAR POWER SYSTEM. THE SYSTEM WILL OPERATE ON A THERMODYNAMIC CYCLE THAT IS A MODIFICATION OF THE CONVENTIONAL RANKINE CYCLE, IN WHICH THE NORMAL BOILER FEED PUMP IS REPLACED BY A "PASSIVE PUMPING MODULE" (PPM) AND THE WORKING FLUID IS A SUITABLE ORGANIC FLUID. THIS NEW ORGANIC VAPOR CYCLE IS ATTRACTIVE BECAUSE IT CAN BE USED EFFECTIVELY WITH MEDIUM TEMPERATURE HEAT SOURCES INCLUDING RADIO- ISOTOPES, REACTORS, OR SOLAR COLLECTORS. THE PARASITIC POWER REQUIRED FOR THE BOILER FEED PUMP IN MEDIUM TEMPERATURE CONVENTIONAL ORGANIC RANKINE CYCLE POWER SYSTEMS TESTED TO DATE CAN BE 20% TO 30% OF THE SYSTEM OUTPUT POWER. BY REPLACING THE BOILER FEED PUMP BY THE PPM, THE PARASITIC PUMPING POWER SHOULD BE ONLY 2% TO 3% OF THE OUTPUT POWER. THUS, THE USE OF THE PPM PROMISES HIGHER SYSTEM EFFICIENCY, LIGHTER WEIGHT, AND HIGHER RELIABILITY FOR SMALL TO MEDIUM SIZE ORGANIC RANKINE CYCLE POWER GENERATORS. A MAJOR PART OF THE RESEARCH WILL BE TO DEVELOP A ZERO-GRAVITY PPM. A PPM HAS BEEN DEVELOPED THAT CIRCULATES FREON IN A TERRESTRIAL SOLAR HEATING SYSTEM. ALSO SOLAR RESEARCHERS AT THE LOS ALAMOS NATIONAL LABORATORY HAVE DEVELOPED A SIMILAR PPM. THE ZERO-GRAVITY PPM WILL USE FEATURES OF THE TERRESTRIAL PPMS ALREADY IN USE IN ADVANCED FREON PHASE-CHANGE SOLAR HEATING SYSTEMS.