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Radioisotope and Nuclear Technologies for Space Exploration

By Robert Charles O’Brien


Radioisotope heat sources and power systems, traditionally fuelled by 238Pu, have been developed and used for spacecraft thermal management and to provide electrical power during many deep space and planetary science missions. The use of fission reactors in space, however, has been limited to high power applications in Earth orbit. Previous ground based research programs conducted by the U.S. Atomic Energy Commission demonstrated the principal of nuclear thermal rocket propulsion but to date, flight heritage of nuclear propulsion has been limited to nuclear-electric propulsion. The development of space nuclear systems and tributary components that are capable of meeting the rigors of space flight is of paramount importance. Performance, lifetime and operational safety under all foreseeable conditions are essential considerations that must be made. The selection of appropriate materials and environmental compatibility is vital to the success of any given design. The ability for radioisotope heat sources to survive the extreme temperatures and mechanical loads associated with launch related accidents, is both legally mandated and necessary for the protection of life and the Earth’s environment. Nuclear fuels for fission systems must provide equal protection during accidents while the integral design ensures that a reactor remains in a safe configuration. A historical overview of nuclear systems for space is presented. Traditional and modern system designs and fabrication techniques are discussed. Applicable solid state and mechanical power conversion methods are described and their performances are evaluated. Consideration is made for the effect of radioisotope selection and heat source encapsulation architecture upon radiation safety. The identification of 241Am as an alternative isotope fuel is made. Other candidate isotopes such as 210Po, 242Cm and 244Cm are assessed.\ud The development of encapsulation methods that are resistant to the extraction and dispersion of the radioactive materials enclosed is increasingly attractive for security reasons. Spark Plasma Sintering\ud (SPS) processes are presented as novel, simple and rapid techniques for the encapsulation of radioisotopic materials within tungsten ceramic-metallic or cermet matrices. Computational modelling via Monte-Carlo simulation has shown that the encapsulation of radioisotopes within heterogeneous tungsten cermet matrices may reduce the neutron, X-ray and Gamma-ray radiation dose delivered to the localised environment. The prevention of fabrication related volatilisation of radioisotopic compounds is fundamental to the success of the encapsulation process. SPS is empirically demonstrated via the use of CeO2 as an inert simulant for radioisotopic compounds such as PuO2, AmO2 and UO2. The chemical compatibility of americium oxides within a tungsten matrix is also demonstrated through pressureless sintering within a Differential Scanning Calorimetric furnace. The techniques developed for radioisotope encapsulation are also demonstrated in context of cermet fuel fabrication for high temperature space power and propulsion reactor systems. The use of tungsten cermet fuels may eliminate material incompatibilities and failures experienced by historical nuclear thermal propulsion programs.\ud Finally, three novel concept applications of nuclear energy as an enabling technology for planetary exploration are presented. Melt penetration of icy surfaces and long range mobility on planetary surfaces is proposed via the use of pulsed high power heat capacitive radioisotope sources. In-situ resource utilization is considered for propellant production. The use of CO2 is proposed as a propellant for a radioisotope thermal rocket in the context of a ‘Mars Hopper’. A CO2 propellant is also considered in the context of a high temperature (3000°C) nuclear thermal propulsion system for a single stage surface ascent vehicle under a Mars sample return mission

Publisher: University of Leicester
Year: 2010
OAI identifier:

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  1. (2006). 6,6’-Bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydrobenzo[1,2,4]triazin-3-yl) [2,2’]bipyridine, an Effective Extracting Agent for the Separation of Americium(III) and Curium(III) from the Lanthanides". Solvent Extraction and Ion Exchange.
  2. (1968). 710 high-temperature gas reactor program summary report. Volume III. Fuel Element development". General Electric.
  3. A Carbon dioxide thermal rocket that utilizes an indigenous resource in raw form for Mars exploration".
  4. (1998). A Counter Current Experiment for the Separation of Trivalent Actinides and Lanthanides by the SETFICS Process". Solvent Extraction and Ion Exchange.
  5. (1998). A Monte Carlo study of the effect of neutron scattering in a fast neutron radiography facility".
  6. (1971). A Preliminary Study of the Nuclear Subterrene". LA-4547. Los Alamos Scientific Laboratory, Loas Alamos,
  7. (1959). A Quasi-iterative Method for Computing Interface Temperature Distributions". Zeitschrift für angewandte Mathematik und Physik. X
  8. (2000). A Radioisotope Powered Cryobot for Penetrating the Europan Ice Shel".
  9. (2007). A Review of the Development and Operational Characteristics of the TALSPEAK Process". Solvent Extraction and Ion Exchange.
  10. (1968). A safety evaluation of SNAP reactor systems". Report of the Committee on the Nuclear Space Program. Atomic Industrial Forum Inc.
  11. (0898). A Survey of Current Russian RTG Capabilities".
  12. Advanced 80 We Stirling Converter Development Progress".
  13. (2007). Advanced Stirling Convertor Testing at
  14. (2008). Advanced Stirling Radioisotope Generator: Design Processes, Reliability Analyses Impact, and Extended Operation Tests.".
  15. (2007). Advanced Stirling Technology Development at
  16. (1998). Amorphous Water Ice".
  17. (1979). An Isothermal Second Order Stirling Engine Calculation Method".
  18. (2007). An Overview of Current and Past W-UO2 CERMET Fuel Fabrication Technology".
  19. (2007). An Overview of Current and Past WUO2 CERMET Fuel Fabrication Technology".
  20. (2009). Annual Technical Progress Report of Radioisotope Power
  21. Ansys Finite Element and multi-physics analysis software package" [computer program]. Version 10. Ansys Inc.,
  22. (2000). Assessment of the Free-Piston Stirling Converter as a Long Life Power Converter for Space".
  23. (2004). Basic Chemical Thermodynamics".
  24. (2007). Chapter 19 - Thermodynamic properties of actinides and actinide compounds".
  25. (2007). Chapter 24 - Actinide Separation Science and Technology". Chemistry of the Actinides and Transactine Elements.
  26. (2007). Chapter 8 - Americium". Chemistry of the Actindes and Transactinide Elements.
  27. (1980). Characterization of silicon nitride single crystals and polycrystalline reaction sintered silicon nitride by microhardness measurements".
  28. (2003). Chemical thermodynamic representation of AmO2-x".
  29. (1995). Chemical Thermodynamics of Americium".
  30. (2000). CMPO-TRUEX Process ad its Applications in the Separation of Actinides from High-Level Liquid Wastes". Mineral Processing and Extractive Metallurgical Review.
  31. (2004). Comparison and physical interpretation of MCNP and TART neutron and γ Monte Carlo shielding calculations for a heavy-ion ICF system".
  32. (1994). Conditions for condensation and preservation of amorphous ice and crystallinity of astrophysical ices".
  33. (2007). CrystalMaker for Mac OS X" [computer program].
  34. (1992). Data Book for Calculating Neutron Yields from (a, n) Reaction and Spontaneous Fission". Japan Atomic Energy Research Institute JAERI.
  35. (2009). Demonstration of a SANEX Process in Centrifugal Contractors using the CyMe4- BTBP molecule on a Genuine Feed Solution". Solvent Extraction and Ion Exchange.
  36. (1990). Densification Efficiency Of Carbon-Carbon Composites".
  37. Department of Energy. "Draft Environmental Impact statement for the proposed consolidation of Nuclear Operations related to production of Radioisotope Power Systems".
  38. (2009). Deployment histort and design considerations for space reactor power systems".
  39. (1973). Design and Development of Prototype Universal Extruding Subterrene Penetrators". LA-5205-MS. Los Alamos Scientific Laboratory,
  40. (1983). Design Evolution and verification of the General-Purpose Heat Source". Fairchild Space and Electronics Company,
  41. (2004). Designing and Demonstration of the UREX+ Process Using Spent Nuclear Fuel".
  42. (2007). Development of Advanced Stirling Radioisotope Generator for Space Exploration".
  43. (1989). Development of Nuclear Rocket Technology".
  44. (2007). DIAMEX-SANEX Solvent Behavior Under Continuous Degradation and Regeneration Operations".
  45. (1989). DIPS power conversion cycle selection".
  46. (1960). Direct Conversion of Heat to Electricity".
  47. (1997). Direct Energy Conversion: Fundamentals of Electric Power Production".
  48. (1971). Direct Energy Conversion".
  49. (2005). Directorate. "Final Environmental Impact Statement For The New Horizons Mission, Volume 1". NASA,
  50. (1988). Division. "Dynamic Isotope Power Subsystem Engineering Unit Flight System Design Report".
  51. (2008). Effect of TiC content on the microstructure and properties of Ti3SiC2-TiC composites in situ fabricated by spark plasma sintering".
  52. (1979). Elementary Design Guidelines for Stirling Engines".
  53. Encyclopedia Asronautica".
  54. (1986). Energy Programs Department. "GPHS-RTG System Explosion Test Direct Course Experiment 5000".
  55. (1985). Environmental Safety Analysis Tests on the Light Weight Radioisotpe Heater Unit (LWRHU)".
  56. (2004). Expedition Mars".
  57. (1986). Experience gained from the Space Nuclear Rocket Program (Rover)". Los Alamos National Laboratory,
  58. (2010). Experimental cermet encapsulation of americium oxides within a tungsen matrix under the simulatated temperature conditions of Spark Plasma Sintering".
  59. (2007). Extraction of Lanthanides(III) and Am(III) by Mixtures of Malonamide and Dialkylphosphoric Acid". Solvent Extraction and Ion Exchange.
  60. (1999). Extreme Electronics for In-Situ Robotic/Sensing Systems".
  61. (1969). Fabrication of cermets of uranium nitride and tungsten or molybdenum from mixed powders and from coated powders".
  62. (2009). Fabrication of prismatic fuel elements for space power and nuclear thermal propulsion reactors by spark plasma sintering".
  63. (1995). Fabrication of silicon nitride nano-ceramics by spark plasma sintering".
  64. (1976). First Viking mission to Mars". Science.
  65. (1968). Fission product behavior within two W–UO2 cermet fuel elements irradiated in a temperature gradient". Nuclear Space Programs Space Systems. General Electric,
  66. (2001). Flowsheet Testing of the Universal Solvent Extraction Process for the Simultaneous Separation
  67. (1995). From Separations to reconstitution - A short history of Plutonium in the US and Russia".
  68. (2000). Fundamental aspects of Hot Isostatic Pressing: An Overview".
  69. (2008). Fundamentals of Nuclear Science and Engineering".
  70. (1986). General-Purpose Heat Source Development: Safety Verification Test Program Explosion Overpressure Test Series".
  71. (1986). General-Purpose Heat Source Development: Safety Verification Test Program Titanium Bullet / Fragment Test Series".
  72. (1987). General-Purpose Heat Source Safety Verification Test Program: Edge-On Flyer Plate Tests".
  73. (1996). General-Purpose Heat Source: Research and Development Program High-Silicon Fuel Characterization Study;
  74. Grafoil Flexible graphite". GrafTech International,
  75. (2008). GRC Supporting Technology for NASA’s Advanced Stirling Radioisotope Generator (ASRG)".
  76. (1999). Health and Safety Executive. "Ionising Radiation Regulations
  77. (2007). Heat-to-electricity thermoacoustic-magnetohydrodynamic conversion".
  78. (1993). High efficiency dynamic radioisotope power systems for space exploration - a status report".
  79. (2007). High Strain Rate Tensile Testing of DOP-26 Iridium".
  80. Hot water Drilling - an overview".
  81. (2001). IceCube Neutrino Telescope Preliminary Design Document".
  82. ICSD Inorganic Crystal Structure Database".
  83. (2008). Idaho National Laboratory, in private communication to author,
  84. (2009). ImageJ" [computer program].
  85. (2010). Information and Numerical Data Analysisand Synthesis (CINDAS), "Thermo Physical Materials Database (TPMD)".
  86. International Atomic Energy Agency. "Evaluated Nuclear Data File (ENDF)".
  87. Introduction to Fluid Mechanics".
  88. (2005). Investigation of radiation damage effects in neutron irradiated CCD ".
  89. (2008). Isolation of Microbes from Lake Vostok Accretion Ice".
  90. (1994). Jet Propulsion Lab (JPL). "Cassini Program environmental impact study Volume 2: Alternate Mission and Power Supply".
  91. (1997). Light-Weight Radioisotope Heater Unit (LWRHU) Sequential Impact Tests".
  92. (1996). Lightweight Radioisotope Heater Unit (LWRHU) Production for the Cassini Mission".
  93. (1971). Liquid Metal MHD Power Conversion".
  94. (2009). Mars Aerial Regional-Scale Environmental Survey (ARES) Coordinate Systems Definitions and Transformations".
  95. (1991). Mars Direct: A Simple, Robust, and Cost Effective Architecture for teh Space Exploration Initiative".
  96. (2003). MCNP - a general Monte Carlo n-particle transport code, version 5". LA-UR-03-1987. Loas Alamos National Laboratories,
  97. (1997). MCNPX - The LAHET/MCNP code merger".
  98. (2002). Measurement of Seebeck coefficient perpendicular to SiGe superlattice Thermoelectrics".
  99. (1987). MHW RTG performance during LES 8/9 and voyager missions".
  100. (2007). Microstructure and Mechanical Properties of Nanostructured Aluminium Consolidated by SPS".
  101. (2006). Mission of Daring: The General-Purpose Heat Source Radioisotope Thermoelectric Generator".
  102. (2006). Mission of Daring: The GeneralPurpose Heat Source Radioisotope Thermoelectric Generator".
  103. (2006). MMRTG Heat Rejection Summary".
  104. (2003). Modelling of HTRs with Monte Carlo: From a homogeneous to an exact heterogeneous core with microparticles".
  105. (2004). Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) Program Overview".
  106. (2009). Neutron sources for in-situ planetary science applications".
  107. (2002). Normalized conceptus doses for abdominal radiographic examinations calculated using a Monte Carlo technique".
  108. (2010). Nuclear Thermal Rockets: History, Benefits and Issues Impacting Future Operations".
  109. (1997). Nuclear thermoelectric power units in Russia, USA and European Space Agency research programs".
  110. (2009). of Idaho National Laboratory in private communication to O'Brien R.C.
  111. (1993). Office of Polar Programs Environment Section. "Environmental Action Memorandum: Installation, Maintenance and Removal of Automatic Weather Stations in Antarctica.". Office of Polar Programs.
  112. (2008). Overview of Multi-Kilowatt Free-Piston Stirling Power Conversion Research at Glenn Research Center".
  113. (2007). Partitioning of Minor Actinides from PUREX Raffinate by the TODGA Process".
  114. (2010). Performance and radiological analyses of a space reactor power system deployed into a 1000–3000 km earth orbit".
  115. (1998). Physical Chemistry Of Ices In The Outer Solar System.".
  116. (2006). Plutonium-238 Recovery From Irradiated NeptuniumTargets Using Solvent Extraction".
  117. (1965). Poodle Heat Source Development And Demonstration Test". MLM-1261.
  118. (1966). POODLE Radioisotope Propulsion Technology".
  119. (1977). Process of making oxygen enriched plutonium dioxide (PuO2)". US patent 4,042,670.1977.
  120. (2009). Production of safe radioisotope heat sources by Spark Plasma Sintering".
  121. Propulsion Laboratorty. "Phoenix Mars Lander".
  122. Propulsion Laboratory. "The Mars Exploration Rover Mission".
  123. (2004). Prototype of a Nuclear Rocket Motor - The IGRIT Reactor". Atomic Energy. 97
  124. (1995). Pustovalov in private communication to A. Fournier-Sicre, Head of ESA Permanent Mission in
  125. (2002). Radial Distributions of Rapidly Varying Currents and Fields in a Cyludrical Conductor".
  126. (2010). Radioisotope fuels for neutron and heat sources for radioisotope power systems and in-situ planetary science applications". Applied Radiation and Isotopes. Article in press
  127. Radioisotope thermionic converters for space aplications".
  128. (1964). Radioisotopic Power Generation".
  129. (1973). Rapid Excavation by Rock Melting - LASL Subterrene Program". LA-5459-SR. Los Alamos Scientific Laboratory,
  130. (2002). Recent Developments in the Development of Partitioning Processes of Minor Actinides from Nuclear Wastes obtained in the Frame of the Newpart European Programme (1996-1999)". Progress in Nuclear Energy.
  131. (1994). Reentry Safety for the Topaz II Space Reactor: Issues and Analyses". SAND94-0484. Sandia National Laboratories,
  132. (2006). Reliability of Radioisotope Stirling Converter Linear Alternator".
  133. (1990). Retardation of Sintering in Heterogeneous Powder Compacts".
  134. (2007). Returning humans to the moon: comparison of chemical engine and nuclear rocket performance as an earth departure stage".
  135. (2002). Review of the historical capabilities and testing of composite and cermet fuels in Los Alamos".
  136. (2010). Reviss Services UK LTD, Discussions on the availability of curium isotopic compounds, in private communication to O'Brien R.C.,
  137. (2005). Rocket And Spacecraft Propulsion". 2nd ed.
  138. (2001). Rocket Propulsion Elements". 7th ed.
  139. (2007). Role and Prospects of Application of
  140. (2007). Russian Nuclear Rocket Engine Design for Mars Exploration".
  141. (2008). Safe radioisotope thermoelectric generators and heat sources for space applications".
  142. (1992). Safety questions relevant to nuclear thermal propulsion".
  143. (1979). Selection of Power Plant Elements for Future Reactior Space Electric Power Systems".
  145. (2007). Separation of Actinide Elements By Solvent Extraction Using Centrifugal Contactors
  146. (2008). Separation of Minor Actinides from Lanthindes by Dithiophosphinic Acid Extractants".
  147. (1998). Shielding analysis of high level waste water storage facilities using MCNP code".
  148. (1993). Sinter Forging as a Tool for Improving the Microstructure and Mechanical Properties of Zirconia Toughened Alumina".
  149. (2006). Sintering of WC-Co powder with nanocrystalline WC by spark plasma sintering". Rare Metals.
  150. (1996). Sintering Theory And Practice".
  151. (2004). Small Radioisotope Power Source Concepts".
  152. (1965). SNAPOODLE Demonstration Design Study".
  153. (2003). Sojourner: An Insider's View of the Mars Pathfinder Mission".
  154. (2008). Solar Nantenna Electromagnetic Collectors".
  155. (2005). SOURCES4C, Calculating Alpha,
  156. (1985). Space Law in the United Nations". Martinus Nijhoff Publishers;
  157. (2006). Space nuclear power: opening the final frontier".
  158. (2006). Space nuclear power: opening the final frontier". Proceedings of: Fourth International Energy Conversion Engineering Conference and Exhibit (IECEC),
  159. (1985). Space Nuclear Power".
  160. (1984). Space Nuclear Safety Program".
  161. (1975). Space power application of the all purpose mini-Brayton rotating unit / Mini-BRU".
  162. Spacecraft Systems Engineering". 3rd ed.
  163. (2009). Spark Plasma Sintering of simulated radioisotope materials in tungsten cermets".
  164. (2005). Spark plasma sintering on nanometer scale WC-Co powder".
  165. (1979). Status Report of the Dynamic Isotope Power System".
  166. (2005). Strategic Management of Marine Ecosystems".
  167. (2005). Subglacial processes".
  168. (1974). Subglacial shearing and crushing, and the role of water pressures in Tills from South-Eat Iceland".
  169. (1965). Surface Displacement of a Convective Elastic Half Space Under an Arbitrary Distributed Fast-Moving Heat Source".
  170. (2009). Systems Committee of the National Research Council, "Radioisotope Power Systems: An Imperative for Maintaining U.S. Leadership in Space Exploration". National Academies Press;
  171. (2004). Table of Radionucleides". Vol 2.
  172. (1991). Technology development issues in space nuclear power for planetary exploration".
  173. (2008). Technology Office of Nuclear Energy. "Advanced Fuel Cycle Initiative". Sandia National Laboratory,
  174. (2006). The 2kW Mini-BRU Electrical Controls Concept and Transient Performance".
  175. (1977). The Effect of Pore Drag on Ceramic Microstructures".
  176. (1986). The Effects of Grain Growth on the Intergranular Porosity Distribution in Hot Pressed and Swelled UO2".
  177. (1968). The Exchange of Isotopically Enriched Oxygen with 238PuO2".
  178. (2002). The Huygens probe system design".
  179. (2002). The Huygens probe: science, payload and mission overview".
  180. (2003). The Mars Underground Mole (MUM): A subsurface penetration device with in situ infrared reflectance and raman spectroscopic sensing capability".
  181. (1968). The Thermal Diffusivity of Ice and Water Betweeen -40 and +60 C".
  182. Thermal and Structural Properties of Fusion Related Materials". United Kingdom Atomic Energy Agency (UKAEA -
  183. (1978). Thermionic Converters And LowTemperature Plasma".
  184. (2004). Thermoacoustic engines and refrigerators".
  185. (2005). Thermoacoustic Piezoelectric Generator (Patent WO/2005/022606)",
  186. (1989). Thermochemical data of pure substances". Vol I & II;
  187. Thermochemical Data".
  188. (2000). Thermodynamics of Energy Conversion and Transport".
  189. (1990). Thermophysical Propeties of Ice, Snow, and Sea Ice".
  190. (1985). Turbulence Models for Near-Wall and Low Reynolds Number Flows- A Review".
  191. (2001). Use of a Mixture of TRPO and TBO for the Partitioning of Actinides from High-Level Waste Solutions of PUREX Origin and its Comparison with CMPO and Other Phosphorous-Based Extractants". Solvent Extraction and Ion Exchange.
  192. (2009). Vacuum Thermal Degradation of Poly(ethylene oxide)".
  193. (1991). Viking Spacecraft". The University fo Texas at
  194. (2007). W/Cu composites produced by pulse plasma sintering technique (PPS)". Fusion Engineering and Design.
  195. (2000). YENISEI"

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