Nuclear Reactors for Space Power, Understanding the Atom Series
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4:=:* irni a I_ = 11111 1 1. 0 .A1-11 C=3. 1=3.- i=a DOCUMENT RESUME ED 054 966 SE 012 470 AUTHOR Corliss, William R. TITLE Nuclear Reactors for Space Power, Understanding the Atom Series. INSTITUTION Atomic Energy Commission, Oak Ridge, Tenn. Div. of Technical Information. PUB DATE 71 NOTE 52p.; Revised AVAILABLE FROM USAEC, P. O. Box 62, Oak Ridge, Tennessee 37830 (Free) EDRS PRICE MF-$0.65 HC-$3.29 DESCRIPTORS *Aerospace Technology; College Science; Instructional Materials; *Nuclear Physics; Physics; Resource Materials; Secondary School Science IDENTIFIERS Atomic Energy Commission ABSTRACT The historical development of rocketry and nuclear technology includes a specific description of Systems forNuclear Auxiliary Power (SNAP) programs. Solar cells and fuelcells are considered as alternative power supplies for space use.Construction and operation of space power plants must includeconsiderations of the transfer of heat energy to electricity andof waste heat dissipation. The shielding of such plants is important,from both efficiency and safety standpoints. The safety of nuclearmaterial handling in space flight is especially crucial. Variousimprovements are proposed concerning present powerplantsLists of relevant reading topics and of motion pictures are included. (TS) LI S DEPARTMENT OF HEALTH, EDUCATION &WELFARE OFFICE OF EDUCATION THIS DOCUMENT HAS BEEN REPRO- DUCED EY,ACTLY AS RECEIVED FROM THE PERSON OR ORGANIZATION ORIG- INATING IT POINTS OF VIEW OR OPIN- -511, IONS STATED DO NOT NECESSARILY , REPRESENT OFFICIAL OFFICE OF EDU- CATION POSITION OR POLICY '4)4f i_NuclearI Reactors for Space Power by William R. Corliss Understanding the Atom Series Booklet ,The Understanding the Atom Series Nuclear energy is playing a vital role in the life of every man, woman, and child in theUnited States today. In the years ahead it will affect increasinglyIl the peoples of the earth. It is essential that all Americans gain anunderstanding of this vital force if they are to discharge thoughtfullytheir responsibilities as citizens and if they are to realizefully the myriad benefits that nuclear energy offers them. The United States Atomic Energy Commissionprovides this booklet to help you achieve such understanding. Edward J. Brunenkant, Director ivision of Technical Information UNITED STATES ATOMIC ENERGY COMMISSION Dr. Glenn T. Seaborg Chairman James T. Ramey. Wilfrid E. Johnson Dr. Clarence E. Larson THE COVER Thq cover is an artist's conception of the SNAP-t0A space pow er system, Rcuctors Jr Spam Power which was launched on April 3, 1965. This was the world's first operation of a nuclear reactor in space.The reactor is the assembly at the right end ofthe space vehicle. Nuclear Reactors for Space Power by William R. Corliss CONTENTS INTRODUCTION 1 PUTTING THE ATOM IN ORBIT 3 It All Started with Feedback 3 Start of the U. S. Space Effort 5 SNAP in Space 7 What Makes a Good Space Power Plant? *10 A Look at the Competition 11 What Does "Ambitious" Mean? 15 HOW A REACTOR SPACE POWER PLANT WORKS 16 Fitting the Pieces Together 16 Megawatts from a Wastebasket 17 Conversion of Heat to Electricity 22 Getting Rid of Waste Heat 29 Shielding Men and Equipment 32 Nuclear Safety 36 IMPROVING THE BREED 38 Boiling Electrons 39 Brayton Versus Rankine 41 Other Ideas 44 READING JST 46 United States Atomic Energy Commission Division of Technical Information Library of Congress Catalog Card Number: 70-169080 1966;1971(rev.) 3 THE AUTHOR William R. Coriissis an atomic energy consultant and writer with 12 years of industrial experience including service as Director of Advanced Programs for the Mar- tin Company's Nuclear Division. Prior industrial connections were with the Flight Propulsion Labo- ratory of the General Electric Company and with Pratt &. Whitney Aircraft Company. Mr. Corliss has B.S. and M.S;degrees in Phys- ics from Rensselaer Polytechnic Institute and the University of Colorado, respectively. He has taught at those two institutions and at the University of Wisconsin. He is the author of Propulsion Sys- tems for Space Flight (McGraw-H1111960), Space Probes and Plan- etary Exploration (Van Nostrand 1965). Scientific Satellites (Gov- ernment Printing Office,1967).Mysteriesofthe Universe (Crowell,1967),Mysteries I3eneaththeSea (Crowell,1970), andcoauthor ofRadioisotopic Power Generation (Prentice- Hall, 1964, )Human Factors Applications in Teleoperator Design and Operation (Wiley, 1971), and Man and Atom (Dutton, 1971), as well as numerous articles and papers for technical journals and conferences. In this series he has written NeutronActivation Analysis, Power .Reactors in Small Packages, Direct Conversion of Energy,Computers, Nuclear Propulsion for Space,Space Radiation, and was coauthor of Pomer _from RadiolSotopes. Nuclear Reactors for Space Power By WILLIAM R. CORLISS INTRODUCTION Some day a rocket Will thrust a manned spacecraftfrom its parking orbit around the earth and injectit into an elliptical transfer orbit intended to interceptthe planet Mars 7 months later. The men in this interplanetarycraft will require electrical power or several purposes,for, according to an old rule of thumb !an live for only -3'ithout fookl,4 clays"vithc: v,.Ler, an,_ 4 minutes withoui air. Enough food can and will be carridalong on that first Mars journey, but there will not be zoom enough in the adventurous craft for all the water and VII'that -will be required, unless these vital fluids are over and over again. The purification and regenerationcof 'R'-iter and air will require electricity. So will thecraft'ss'exuntents and radios. Still more power will be needer: tokeep the cabin at a livable temperature. For some long space voyages requiring largpovwer sup- plies, chemical forms of energyrocket tz-as,battery fluids, and hydrogendo not have enough eners7.- perunit mass (joules per kilogram orkilowatt-hours aer pound). The huge quantities of fuel and midizer thatinadd have to be carried along would simply w-aigh too rnuct-..... solar power has limitations for some mission,The sun's contribution of energy, which is. 1400 watts power per square meter, or 150 watts per squarefoot, al-..the earth's surface, will steadily decrease as the spacpLraftswings outward toward Mars. Mars is about 1.5 tim.9. as farfrom the sun as the earth is, so the solar-energydensity is reduced by a factor equal to tho square of 1.5 J x% 9/4), 5 1 1-IA0111,0,0' I' fipt1hiligAll mksills lecoc01 Iii)sof ofit theOM Yishod s,bilubooms, kseOrd h.like b rilltors i1er iiroctors,''tosfe Ruclorhot to ellukmodide sOce, is 01/010, =^2.-"tv,r2t-.41xtv,wittiamar...7.2.72.7a..enaaa....*......-..r..._~w......,-,...., or 2.25. Huge, unwieldly arrays ofmirrors or solar cells would therefore be needed to capture enough solar energy for a manned spacecraft operating near Mars.However, small unmanned spacecraft, such as the MarinerMartian probes, find solar cells sufficient for the smallamounts of power they require. In a situation wherellrgeamounts of power are needed overlongperiods of time, the best source of electricity is a nuclear reactor, which uses energycontained in fission- able uranitan. Uranium-235 (23513) contains 100,000times as much energy per unit mass as the bestchemical fuels. This booklet describes the principles of nuclear-reactor space power plants and shows how they willcontribute to the exploration and use of space. It compares themwith chemical fuels, solaz- cells, and systems using energyfrom radioisotopes. PUTTING THE ATOM IN ORBIT it All StarZed with Feedback When the chaos of World War H subsided, it was appzrent that two important technical developments had occurred. The Germans had developed a large rocket, the V-2. This accomplishment fulfilled the prophesles made years be- fore by the American rocket experimenter, Robert Goddard, the German space pioneer, Hermann Oberth, and the far- sighted Russian, Konstantin Ziolkovsky. The second devel- opment, the atomic bomb, introduced a new,extremely compact form of energy that might be used to propel space- craft, operate equipment, and sustain men on board. In the late 1940s many scientists and engineersmused about the possibilities of combining the rocket andthe atom. Space travel, however, was still a dream, and, besides, nuclear power had not been harnessed even for terrestrial use. Other matters dominated the nationalinterest. An ex- ception to this situation, however, was found inProject Feedback, a cold-war study of military reconnaissance satellites, sponsored by the 13. S. Air Force and carried out by the Rand Corporation at Santa Monica, California. Dur- ing Project Feedback the first serious studies weremade 7 3 ! i , I of obtaining satellite power from fissioningtr2anium and from radioactive isotopes. The relatively high power requirementsa few kilo- watts (as much as the output of a small outboardmotor) for some proposed satellites led the U. S.Atomic Energy Commission (AEC) in 1951 to request a seriesof nuclear- power-plant studies from industry. These studies, com- pleted in 1952, concluded that both fission andradioisotope power plants were technically feasible for use onsatellites. At that time there were no rockets capable oflaunching a satellite, although the first intercontinental ballisticmis- siles were being developed. But the need for nuclear power in space had been recognized. Theoreticalstudies con- tinued even though ther, was not yet any programof space exploration. Start of the U. S. Space Effort The official U. S. scientific space effort began in1955 when President Eisenhower announced the Vanguardsatel-