NETS - 2017 Nuclear and Emerging Technologies for Space ANS Aerospace Nuclear Science and Technology Division CONFERENCE PROCEEDINGS NASA Table of Contents Paper 19763 – A New Manned Space Flight Mission for NASA (p. 1) Paper 20048 – Nuclear & Thermal Hydraulic Design for a Low-Enriched Nuclear Thermal Rocket (p. 9) Paper 20099 – The Paucity Problem: Where Have All the Space Reactor Experiments Gone? (p. 19) Paper 20157 – Overview of Rayleigh-Taylor Instability & the Impact on Target Design for a Pulsed Fusion / Fission Propulsion System (p. 29) Paper 20159 – Progress on Fusion Modeling & the Charger-1 Pulsed Power Facility at UAH (p. 37) Paper 20176 – Analysis of Operating Strategies Using Alternative Target Designs for 238Pu Production (p. 45) Paper 20177 – Optimal Nuclear Thermal Propulsion Thrust Level for Human Mars Exploration (p. 55) Paper 20182 – Idaho National Laboratory Radioisotope Power Systems Nuclear Operations: Readiness Assessments Supporting a Nuclear-enabled NASA Mission (p. 66) Paper 20183 – Cassini Power Subsystem (p. 74) Paper 20194 – 10 We Radioisotope Thermophotovoltaic (RTPV) Power Source Demonstration (p. 82) Paper 20224 – Thermal-Control Consideration & Preliminary Analysis of a Heat Pipe Cooled Space Reactor Power System (p. 90) Paper 20458 – Criticality Safety Design and Analysis of the Heat-pipe Nuclear Reactor (p. 100) Paper 20482 – Control System Requirements for a Nuclear Thermal Propulsion System (p. 108) Paper 20484 – Updated Mars Mission Architectures Featuring Nuclear Thermal Propulsion (p. 118) Paper 20512 – Zirconium – Rates of Reaction for a Common Getter Material (p. 125) Paper 20536 – Robust Exploration & Commercial Missions to the Moon Using NTR / LANTR Propulsion & Lunar-Derived Propellants (p. 135) Paper 20537 – Optimization of Radiation Shielding for Space Nuclear Propulsion (p. 143) Paper 20547 – Survey of Fuel System Options for Low Enriched Uranium (LEU) Nuclear Thermal Rockets (p. 153) Paper 20574 – Autonomy for Space Reactor Power Systems (p. 165) Paper 20575 – TERRA Project: A Brazilian View for Nuclear Energy Application to Space Exploration (p. 172) Paper 20591 – ELMOE: Europa Lander, Melter, & Oceanic Explorer (p. 180) A New Manned Space Flight Mission for NASA Philip C. Fisher Ruffner Associates, LTD., 5306 Peace Court, Fairfield, CA 94533 1-707-427-8035, [email protected] Abstract: Definition of a manned space flight mission into deep space was initiated by an unsolicited proprietary proposal to NASA Headquarters in February 1973. That and subsequent similar proposals to NASA of 1998, 2004, and 2013 are contained in the Philip C. Fisher Papers of the Niels Bohr Library and Archives of the American Institute of Physics. The purpose of this presentation is to encourage NASA to decide if it is willing to ask the United States Congress to fund the first flight of the mission involving specified leading governing nations to make a contribution to world peace. Key discussion covers the history of unsolicited proposals (1973–2013), potential international cooperation including China, propulsion concepts (gas dynamic fusion, magnetoplasma engines), flight characteristics for deep space exploratory missions (~2035 and ~2050), and management/agenda outlines for international collaborative meetings. Nuclear and Thermal Hydraulic Design for a Low-Enriched Nuclear Thermal Rocket Samuel J. Cope, Joseph J. Cambareri, Nina C. Sorrell, J. Michael Doster Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 Abstract: This work describes the core design and thermal hydraulic analysis of an LEU-fueled nuclear thermal rocket (NTR) to support human Mars missions (DRA 5.0). The core consists of a cylindrical block of graphite with 483 hexagonal (U0.1, Zr0.45, Nb0.45)C fuel elements and 978 ZrH1.8 moderator elements (approx. 2:1 ratio) with active fuel height of 70 cm and diameter of 80 cm. It utilizes 12 rotating BeO/B4C control drums and a 28 cm BeO top reflector. The once-through hydrogen coolant design produces an exit temperature of 1326 K, specific impulse of 615 s, and thrust of 111.2 kN. Launch criticality safety analyses demonstrate subcriticality (keff = 0.89919 ± 0.00078) in the limiting case of freshwater submersion by deconstructing the core into one-sixth sections upon impact. The Paucity Problem: Where Have All the Space Reactor Experiments Gone? John D. Bess and Margaret A. Marshall Idaho National Laboratory, Idaho Falls, ID 83415 Abstract: Discusses the scarcity of historical space nuclear reactor experiment evaluations within the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and International Reactor Physics Experiment Evaluation Project (IRPhEP) handbooks (only 12 evaluations available). The paper outlines the urgent need for recovering, archiving, and digitizing legacy experimental data (e.g., Rover, NERVA, SNAP, SP-100, TOPAZ, UKS-1M, ZPPR, ORCEF) before tribal knowledge and records are lost, highlighting its value for modern small modular reactors, code validation, and advanced fast reactor simulations. Overview of Rayleigh-Taylor Instability and the Impact on Target Design for a Pulsed Fusion / Fission Propulsion System Brian D. Taylor, Jason T. Cassibry, Robert B. Adams Propulsion Systems Department & Propulsion Research & Development Laboratory, NASA MSFC / Propulsion Research Center, UAH Abstract: Presents an overview of the Magneto-Rayleigh-Taylor Instability (MRTI) for pulsed Z-pinch targets used in the Pulsed Fission-Fusion (PuFF) propulsion concept. Explores mitigation mechanisms including frozen deuterium/uranium wires, dielectric coatings on metallic liners, axial magnetic field shearing, and tailored density profiles to stabilize plasma implosions and achieve sufficient burn. Progress on Fusion Modeling and the Charger-1 Pulsed Power Facility at UAH Ross J. Cortez, Jason T. Cassibry, Robert B. Adams, Glen E. Doughty, Brian D. Taylor, Anthony J. DeCicco University of Alabama in Huntsville / NASA MSFC / University of Maryland Abstract: Reviews updates to the 3-D smoothed particle hydrodynamics code SPFMax, focusing on charged particle stopping power modeling in hot, dense plasmas (D6Li fuel cycle). Details the refurbishment and operational progress of the Charger-1 pulsed power facility (formerly Decade Module 2, 3 TW, 580 kJ, 2 MA at 1.5 MV) at UAH, including oil purification, water deionization, trigger systems, and magnetically insulated transmission line (MITL) fabrication. Analysis of Operating Strategies Using Alternative Target Designs for 238Pu Production Tomcy Thomas, Rapinder S. Sawhney, Steven R. Sherman University of Tennessee, Knoxville / Oak Ridge National Laboratory Abstract: Evaluates discrete-event simulation models of chemical processing campaigns to re-establish 238Pu supply for NASA deep-space missions. Analyzes alternative reactor target configurations, comparing the original target design with a Mod 1 design (+50% 237Np oxide) and Mod 2 design (zirconium-alloy-clad, no aluminum). Results indicate that Mod 2 significantly reduces required target throughput (down to 96-126 targets/year from 432) and achieves the highest daily production rates (up to 8.3 g/day). Optimal Nuclear Thermal Propulsion Thrust Level for Human Mars Exploration C. Russell Joyner II, Timothy Kokan, Daniel J. H. Levack, John Crowley, Frederick Widman Aerojet Rocketdyne Abstract: Assesses optimal NTP engine thrust and staging configurations for human Mars exploration under NASA's Evolvable Mars Campaign (EMC). Concludes that a three-engine configuration with individual engine thrust of 15 to 25 klbf (66.7 to 111.2 kN) provides the most robust, mass-optimal, and cost-effective design across varied aggregation orbits (LEO, HEO, LDHEO), transfer times, and engine-out scenarios. Idaho National Laboratory Radioisotope Power Systems Nuclear Operations: Readiness Assessments Supporting a Nuclear-enabled NASA Mission Kelly L. Lively, Drake C. Kirkham Idaho National Laboratory Abstract: Details the multi-tier regulatory requirements (10 CFR 830, DOE O 425.1, DOE O 414.1, NQA-1) and independent readiness verification process (MSA, CRA, DOE RA, PRR, SRR) implemented at INL's Space and Security Power Systems Facility (SSPSF) to support assembly, testing, and delivery of plutonium oxide-fueled Multi-Mission Radioisotope Thermoelectric Generators (MMRTGs), specifically for the Mars 2020 mission. Cassini Power Subsystem Jonathan Grandidier, John B. Gilbert, Gregory A. Carr Jet Propulsion Laboratory, California Institute of Technology Abstract: Reviews the 20-year operational history and telemetry of the Cassini power subsystem, powered by three GPHS-RTGs (containing 32.7 kg PuO2, yielding 882.1 W BOL electrical power at 6.69% efficiency). Covers degradation mechanisms (30.5% over 19 years), environmental solar effects during Venus/Earth flybys, and electrical bus anomalies associated with the Cassini Plasma Spectrometer (CAPS) instrument that led to its permanent shutdown in 2012. 10 We Radioisotope Thermophotovoltaic (RTPV) Power Source Demonstration Jivan Khatry, Juha Nieminen, Josh Smith, Kari Slotten University of Idaho / USC / UT Knoxville / Embry-Riddle / Center for Space Nuclear Research Abstract: Presents the conceptual design and multiphysics modeling of a 1U CubeSat-sized 10 We radioisotope thermophotovoltaic (RTPV) generator using an AmO2/W cermet core (1320 K) with tantalum photonic crystal selective emitters and tandem filters matched to 0.6 eV InGaAs PV cells. System achieves 8.4% conversion efficiency (12.6 We output) and presents shielding analyses for low-energy gamma and secondary neutron radiation. Thermal-control Consideration and Preliminary Analysis of a Heat Pipe Cooled Space Reactor Power System Mingyang Ma, Qilin Xie, Wenfeng Liang, Sanbing Wang, Xiaoqiang Fan Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics Abstract: Examines thermal-control architecture and independent parameters for a 40 kWe heat pipe cooled space reactor power system using sodium heat pipes, Stirling engines, and water-cooled radiators. Evaluates heat exchange resistances, steady-state temperatures (core at 1200 K, Stirling hot-end at 900 K, cold-end at 550 K), and provides a system-level transient physical modeling framework. Criticality Safety Design and Analysis of the Heat-pipe Nuclear Reactor Wang SanBing, Xie Qilin, Guo Simao, He ChaoHui Institute of Nuclear Physics and Chemistry, CAEP / Xi’an Jiaotong University Abstract: Re-evaluates the criticality safety of the SAFE-400 space reactor during launch abortion and water/sand immersion scenarios using MCNP. Demonstrates that while control drums and Re spectrum shift absorbers aid safety, complete core disassembly/breakage upon impact is the most reliable strategy to ensure subcriticality in limiting submersion accidents. Control System Requirements for a Nuclear Thermal Propulsion System A. Hasse, M. Smith, B. Pershke, S. Gilliam, D. Adams, L. Qualls University of Tennessee, Knoxville / Oak Ridge National Laboratory Abstract: Develops a dynamic Simulink/Matlab simulation coupling point kinetics, heat transfer, and hydrogen flow for startup of a Small Nuclear Rocket Engine (SNRE). Identifies key operating limits: control drum rotational velocity must be ≤ 0.7°/s to prevent thermal shock in the fuel, hydrogen flow must be initiated simultaneously with drum rotation, and steady-state propellant flow should be 8–9 kg/s. Updated Mars Mission Architectures Featuring Nuclear Thermal Propulsion Mitchell A. Rodriguez, Thomas K. Percy Jacobs Engineering Group / NASA MSFC Abstract: Analyzes updated 2033 crewed Mars mission architectures using Low Enriched Uranium (LEU) NTP stages integrated with SLS and Orion modules. Demonstrates that using High Elliptical Orbit (HEO) aggregation reduces crew vehicle stack mass to 251.4 mt (a ~30% reduction compared to DRA 5.0 LEO aggregation) while reducing heavy-lift launch requirements and mission complexity. Zirconium – Rates of Reaction for a Common Getter Material Christofer E. Whiting, Chadwick D. Barklay, David F. Woerner University of Dayton Research Institute / Jet Propulsion Laboratory Abstract: Measures reaction rates of palladium-encapsulated zirconium getters at 630 °C for water, hydrogen, and methane. Reaction rates are fastest for hydrogen, followed by water, and slowest for methane. Hydrogen gettering exhibits first-order kinetics but is inhibited by the presence of gas-phase water and surface oxides. Robust Exploration and Commercial Missions to the Moon Using NTR / LANTR Propulsion and Lunar-Derived Propellants Stanley K. Borowski, Stephen W. Ryan, Laura M. Burke, David R. McCurdy, James E. Fittje, Claude R. Joyner NASA Glenn Research Center / Vantage Partners / Aerojet Rocketdyne Abstract: Explores lunar transportation architectures incorporating LO2-augmented NTR (LANTR) engines utilizing lunar-derived oxygen (LLO2) from volcanic glass and polar ice deposits. LANTR provides variable thrust and Isp via supersonic O2 afterburning, enabling reusable lunar transfer vehicles, reduced IMLEO, and rapid 24- to 36-hour commuter shuttles between Earth and the Moon. Optimization of Radiation Shielding for Space Nuclear Propulsion Jarvis A. Caffrey Oregon State University / NASA MSFC Abstract: Applies a Multi-Objective Evolutionary Algorithm (MOEA) coupled with MCNP6 to optimize layered shadow shielding (tungsten, boron carbide, LiH) for nuclear thermal propulsion. Employs Pareto-front optimization and distance-to-Pareto fitness metrics to balance shield mass against transmitted radiation dose and propellant heating. Survey of Fuel System Options for Low Enriched Uranium (LEU) Nuclear Thermal Rockets Kelsa Benensky, Paolo Venneri, Michael Eades, Samantha Rawlins University of Tennessee, Knoxville / Ultra Safe Nuclear Corporation / University of Michigan Abstract: Compares high-temperature structural materials for LEU NTP fuels (<20 wt% 235U), including graphite composites ((U,Zr)C-graphite), tungsten cermets (W-UO2/UN), and refractory carbides (SiC, ZrC, TiC). Infinite lattice calculations show refractory carbide matrices provide superior reactivity (kinf) and high-temperature capability, allowing unmoderated or lightly moderated compact LEU core designs. Autonomy for Space Reactor Power Systems David M. Sikorski, Richard T. Wood University of Tennessee, Knoxville Abstract: Discusses autonomy requirements for space reactor power systems (SRPS) operating unattended in deep space under communication delays. Details architectural needs for intelligent control, continuous condition monitoring, fault management (detection, isolation, reconfiguration), and mission assurance over reactor protection. TERRA Project: a Brazilian View for Nuclear Energy Application to Space Exploration Lamartine Guimarães, Guilherme Borges Ribeiro, Jamil Alves do Nascimento, Élvis Falcão de Araújo, Francisco Antônio Braz Filho, Artur Flávio Dias, Valeria S.F.O. Leite Institute for Advanced Studies (IEAv) / UNIP, Brazil Abstract: Outlines the Brazilian TERRA project developing enabling space nuclear power technologies (0.1 to 1000 kWe). Progress includes a fast micro-reactor core concept (UN fuel, Mo13Re cladding, lead-cooled), experimental Stirling convertor prototypes, a 300 kW electric furnace testbed for a closed Brayton cycle, copper-water thermosiphons, and passive multi-fluid (Tesla) turbines. ELMOE: Europa Lander, Melter, and Oceanic Explorer Lucas Beveridge, Weylin MacCalla, Hannah Moore, Rittu Sam Raju, Jonathan Scherr Idaho State University / Embry-Riddle / Texas A&M / University of Michigan Abstract: Proposes a conceptual mission architecture to explore Europa's subsurface ocean consisting of a surface lander, a 250 kWt compact fission reactor melt probe (25 cm diameter, LEU/ZrH-NaK or HEU/UN-BeO), an untethered ice-embedded RF transceiver relay communications trail, and a deployable ocean exploration submarine carrying up to 20 kg of scientific instruments.