Nuclear PowerFission and Radioisotope

Presented to:Propulsion and Power Panel

Aeronautics and Space Engineering BoardNational Research Council

byJoseph J Nainiger

Alphaport, IncMarch 21, 2011

Presentation Outline

• NASA’s need for Space Nuclear Power• Radioisotope Power Systems• Fission Power Systems• Nuclear Power Technical Challenges• Nuclear Power Infrastructure/Facility Needs

NASA Needs for Space Nuclear Power

• Radioisotope Power Systems– Planetary robotic landers and rovers (100’s We class)– Outer planet robotic space probes (100’s We class)– Planetary human exploration – powering rovers (1 kWe class)

and stand-alone science experiments (i.e., ALSEP – 100’s We)– Power source for robotic spacecraft using electric propulsion

(REP - 100’s We class)• Fission Power Systems

– Outer planet robotic space probes (~ 1 kWe)– Planetary human exploration (base power 10’s kWe)– Nuclear Electric Propulsion (NEP)

• Outer planet robotic space probes (100’s kWe)• Human exploration (several MWe’s)

Radioisotope Power Systems

5

Past NASA Missions Using RPSIncluding Moon and Mars

Apollo Voyager

Galileo Ulysses Cassini

Viking

Since 1961, 41 RTGs have been used on 23 US space systems.

6

RPS Plays a Vital Role in NASA’s Future

• For many Science missions, the RPS (power and heat) is enabling.– Most outer planet and beyond spacecraft– Certain solar and inner planet missions– Certain Mars and other surface applications

• For Human Exploration:– RPS can be fielded to support precursor lander/rover missions.– RPS is an option for entry-level power and heat for human missions and surface operations.

• Multimission RPS (MMRTG and ASRG) are being developed with NASA SMD funds– MMRTG first flight scheduled on Mars Curiosity Rover launching this year– ASRG first flight opportunity potentially on a Discovery class mission 2015-2016

• Improved RPSs can be developed to provide full range of capabilities.– Robotic spacecraft and surface missions– Radioisotope Electric Propulsion (REP)– Human planetary surface missions (rovers and/or stand-alone science experiments)

• Lightweight components are needed to fill technology gaps for RPS system development.

– High-efficiency energy conversion (reduce amount of Pu-238 needed)– Heat rejection– PMAD

• Advanced power conversion technology (Advanced Thermoelectrics, Thermo Photovoltaic – TPV, and Advanced Stirling Duplex) is being funded by NASA SMD

Fission Power Systems

8

U.S. Has Pursued Several Aerospace Nuclear Fission Development Programs Since 1945

1946-1961, Aircraft Nuclear Propulsion Project

1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

ANP

SNAP-2, 8, 10, 50

MPRE 1958-1966, Medium Power Reactor Experiment

710 1962-1968, 710 Reactor

1957-1973, Systems for Nuclear Auxiliary Power

1953, “Nuclear Energy For Rocket Propulsion”, R. W. Bussard

Rover/NERVA 1955-1973, Nuclear Thermal Rocket

SPAR / SP-1001984-1992, SP-100

SPR 1965-1968, Adv. Space Nuc. Power Program (SPR)

1965, SNAPSHOT

MMW1985-1990

2005

2003 - 2005 NSI & Prometheus

SNTP1987-1993

9

Significant Space Fission Technology Development Has Been Conducted

• Space Power– 36 Systems Flown (1 U.S., 35 Russian)– 5 U.S. ground test reactors operated

ReactorSystems

• Nuclear Thermal Propulsion– 20 Ground Test Reactors Operated

No U.S. Flight and Ground Test Experience Since 1972

U.S.SNAP-10A

RussiaBUK

RussiaTOPAZ

10

Fission Technology Enables Or Enhances…

• Fuel energy densities ~ 107 that of chemical systems• In-space Power and Propulsion

– Power and propulsion independent of proximity to sun or solar illumination• Constant power level available for thrusting and braking

– Go where you want, when you want• Expanded launch windows• Enhanced maneuverability• Faster trip times / reduced human radiation dose

• Surface Power– Provides power-rich environments

• Telecom• Habitat• Insitu Resource Utilization / Propellant Production (ISRU / ISPP)

– Enables planetary global access– Enables Lunar overnight stays

• Fission power non-nuclear component and system technology is being developed by NASA’s Office of Chief Technologist (OCT) “Game-Changing” Program (formerly developed by ESMD ETDP)

11

Fission Power Summary

• Fission power and propulsion enable/enhance key elements – Surface power & NEP cargo for long-duration human lunar missions– NEP for cargo missions to Moon and Mars – Surface power & NEP for human Mars surface missions

• Current NASA fission project is addressing non-nuclear subsystem development and non-nuclear system testing and could be fielded in the timeframe of this study

– The nuclear design is based on state-of-practice terrestrial nuclear fuels (UO2) and materials (SS)

– Increased DOE participation needed to address the nuclear reactor and shielding • MWe systems can be fielded only IF aggressive and sustained technology development efforts are

increased immediately…– Fuels– Materials– Shielding– Power Conversion– Power Management & Distribution (includes NEP Power Processing)– Heat Rejection– Propulsion

• Significant, but dated technology base exists• Technology (knowledge and art) recapture will be a key• Infrastructure development can pace technology development• Opportunities exist to leverage technology investments

Nuclear Power Technical Challenges• Radioisotope systems

– Lightweight components (power conversion, heat rejection, PMAD)– High efficiency power conversion (reduce amount of PU-238 )– Sub-kW electric propulsion sub-system (for REP)– Infrastructure (separate chart)

• Fission Systems– Infrastructure reestablishment (separate chart)– Technology capture (SP-100, JIMO)– High temperature fuels and materials (especially for NEP applications)– Shielding– Autonomous control– Lifetime– Dynamic power conversion– Heat rejection– PMAD– High power thruster technology (for NEP)– Ground Testing (subsystems and systems)

Nuclear Power Infrastructure/Facility Needs

• Radioisotope Systems– Domestic production of Pu-238 (5 kg/year)***– Increase capabilities to assemble larger RPSs

• Fission Systems– Fuels and materials fabrication– Fuels & materials irradiation facilities– Physics criticals facilities– Ground test facilities– Fast-spectrum Test Reactors– Large EP thruster test facilities– Vehicle integration facilities– Launch site facilities– Fuel & reactor shipping & transportation facilities

*** CRITICAL NEED