National Aeronautics and Space Administration

Nuclear and Emerging Technologies for Space (NETS) 2015 Conference

Nuclear Systems Kilopower Project Overview

Presented by: Don Palac, NASA GRC Co-authors: Marc Gibson, Lee Mason, NASA GRC Patrick McClure, DOE/NNSA/LANL R. Chris Robinson, DOE/NNSA/Y-12

February 23, 2015

www.nasa.gov/directorates/spacetech/game_changing_development Kilopower: Kilowatt-class Fission Power for NASA’s Needs

Too Small… Current Radioisotope Power Too Big… Traditional Fission Power Systems (RPS) Systems (FPS)

140 W 40 kW

300 kW 110 W

Just Right… • 0.5 to 10 kWe; >10 Year design life • Available Uranium-235 reactor fuel 10 kW • Passive Na heat pipe cooling • Stirling convertors from ASRG 800 W • Low power simplifies nuclear design • Compact size permits ground testing in existing DOE facilities

2 A “Critical” Starting Point

• Proof-of-Concept Test . LANL-sponsored test at DOE , DAF Flattop Device Assembly Facility (DAF) Critical Experiment • Test Configuration . Highly core with central hole to accommodate heat pipe . Heat transfer via single water heat pipe . Power generation via two Stirling convertors developed during early phases of ASRG Project • Significance . First-ever heat pipe cooled fission experiment . First-ever Stirling engine operation with fission Notional Flight heat Concept . Demonstration of nuclear reactivity feedback and dynamics with prototype components • Test Objectives . Use electric power generated from nuclear heat to power a load (light panel) . Demonstrate that basic reactor physics are well characterized and predictable using current GRC EE35-Buzz analytic tools Stirling Convertor Assembly Demonstration Using Flattop Fissions

Sept 13, 2012: Success! • 24 Watts Produced • Completed in Less than 6 Mo. • Total Cost Less than $1M

Proof that a ground test can be conducted quickly and affordably

4 Kilopower – Overall Objectives & Elements • Big Idea: 1 to 10 kWe – A compact, low cost, scalable fission reactor for Kilopower Technology science and exploration • Innovation: – KiloPower: novel integration of available U235 On-orbit test of fuel form, passive sodium heat pipes, and flight- variable conductance ready Stirling convertors heat pipe radiator • Impact: under steady-state & – Reduces NASA dependence on Pu238 transient conditions – Provides modular option for HEOMD Mars surface missions

– Protects an option for other NASA .5 to 10 kWe missions where solar power is not feasible Full-scale nuclear test of – Bridges the gap between Radioisotope Power reactor core, sodium heat pipes, and Stirling Systems and 40 kWe class fission power technology convertors at prototypic • Goals: operating conditions – Nuclear-heated test of prototype U235 reactor core coupled to flight-like Stirling convertors • 10X the power of current RPS – Detailed design concept that verifies scalability Assembled with available to 10 kWe for Mars-surface-scale applications • – Prepare for flight test of titanium-water heat component technologies pipe radiator on ISS to verify Zero-G performance • Tested in existing facilities 5 Kilopower Prototype Demonstration

• Approved project to complete non-nuclear system test at GRC followed by nuclear demonstration test at DAF . Plan to verify system-level performance of flight-like reactor core, heat pipes, and power conversion at representative operating conditions (vacuum, temperature, power) . Establishes technical foundation for 1 to 10 kWe-class systems . Recognized by SMD and HEOMD as critical first step toward flight capability

Kilowatt Reactor Using Stirling Technology (KRUSTy)

Kilopower Thermal Prototype & Thermal-Vac System Test HEU Reactor Critical Concept Materials Testing (Year 1) with DU Core (Year 2) Experiment (Year 3) at the

at GRC and NNSA/Y-12 at GRC Nevada Nuclear Security Site6 Kilopower Project Plan by Element

Task FY15 FY16 FY17 FY18 Kilopower Finalize system design Perform non-nuclear Install reactor core Initiate modifications Prototype Test and assemble system verification and perform nuclear for Mars surface components test at GRC test at Nevada power 10 kWe Nuclear Security Site technology demo Mars Kilopower Develop 10 kW-class Perform lander and Generate preliminary Generate detailed System Concept power system ISRU integration design of 10 kWe design and concept of concept for Mars studies Mars surface power operations surface missions system Kilopower Radiator Design high Fabricate high Perform thermal Perform launch Test on ISS temperature radiator temperature radiator vacuum testing at vibration testing at derived from SBIR derived from SBIR GRC GRC designs designs

7 Kilopower Team

NASA GRC

DOE Nevada National Advanced Cooling Security Site Technologies, Inc.

Sunpower, Inc.

DOE Los Alamos National Laboratory DOE Y-12 National Security Site NASA JSC NASA MSFC

8 Other NETS Kilopower 2015 Papers

• 5074/Integrated Surface Power Strategy for Mars – Michelle Rucker (NASA JSC) • 5135/Thermal Power Scaling of the Kilopower Reactor Concept – Dave Poston (DOE Los Alamos National Laboratory) • 5069/High Temperature Water-Titanium Heat Pipes for Spacecraft Fission Power - Bill Anderson (ACT)

Related Papers • 5050/Low-Cost Radiator for Fission Power Thermal Control – Taylor Maxwell (ACT) • 5115/Status Update on the Fission Surface Power Technology Demonstration Unit – Max Briggs (NASA GRC) • 5126/Computational Predictions of the Reactor Simulator Subsystem at NASA GRC – Terry Reid (presented by Max Briggs)