22.033 Final Design Presentation
Vasek DostalKnut Gezelius
Jack HorngJohn KoserJoe Palaia
Eugene ShwagerausAnd Pete Yarsky
With the Help of
Kalina GalabovaNilchiani Roshanak
Dr. Kadak
May 15th, 2003 22.033, Mission to Mars
Our Vision
Use nuclear technology to get people from Earth to Mars and back
May 15th, 2003 22.033, Mission to Mars
Outline
•Mission plan
•Decision methodology
•Space power system
•Surface power system
•Conclusions
May 15th, 2003 22.033, Mission to Mars
Mission Plan Summary
• Precursor 1– Telecommunication nuclear powered
satellite in Mars orbit
• Precursor 2– ISRU and surface nuclear reactor
demonstration / Sample Return
• Manned Missions– Establish the infrastructure– Send the people– Bring them back
May 15th, 2003 22.033, Mission to Mars
Mars Nuclear Telecom Satellite
• Primary Objectives• Validate space reactor system• Validate nuclear electric propulsion system• Provide high data rate communications.
• Increases science yield. In space, power is knowledge.
• Secondary Objectives• Orbital video and hi-res pictures.• High power Mars orbit experiments
(active radar, etc.)
May 15th, 2003 22.033, Mission to Mars
ISRU & Surface Reactor Demo / Sample Return
•Primary Objectives:•Validate Mars surface reactor technology•Validate Mars surface ISRU
• Secondary Objectives•Produce fuel for sample return•Return Martian rocks to Earth
May 15th, 2003 22.033, Mission to Mars
Mars Infrastructure
• Launch Window 1
• Launch 2 Nuclear Powered Transfer Systems• Launch first Earth Return Vehicle• Launch first set of surface Infrastructure
• ERV waits in Mars Orbit• Reactor deployed, ascent stage fueling begins• Transfer Systems return to Earth for reuse
May 15th, 2003 22.033, Mission to Mars
Manned Exploration
• Launch Window 2
• Refuel all 3 Transfer Systems (sitting in LEO)• Launch 2nd ERV & Surface Infrastructure• Launch Transit/Surface Hab• Crew1 meet Hab in HEO
• Crew Lands near existing infrastructure• Transfer Systems return to Earth for reuse
May 15th, 2003 22.033, Mission to Mars
Manned Exploration
•Launch Window 3
•Crew Meets ERV in Mars Orbit, return.•More infrastructure sent to Mars.•Second Crew Deployed.
•This Plan is similar to NASA’s Design Reference Mission, but modified to take advantage of Nuclear Electric Propulsion.
May 15th, 2003 22.033, Mission to Mars
Electric Propulsion Options
Precursor cargo missionsArray of advanced Ion / Hall thrusters
Power 10 – 80 kW
Isp3000 – 10000 sec
Thrust 1 – 3 N
May 15th, 2003 22.033, Mission to Mars
Electric Propulsion (Manned)
Variable Specific Impulse Magnetoplasma Rocket
– VASIMR -
10 MW of power
May 15th, 2003 22.033, Mission to Mars
Space Power Goals
• Low mass
– <3 kg/kWe
• Scalable
– 200-4000 kWe
• Simple and reliable– No moving parts
• Multiple round trips
May 15th, 2003 22.033, Mission to Mars
Space Power Unit
• High temperature heat rejection– Reduces the radiator size
• Thermo Photo Voltaic cells– High efficiency power conversion (up to
40%)– No moving parts
• Molten salt coolant– High temperature, low pressure coolant– Good heat transport medium
• Ultra-compact high power density reactor
May 15th, 2003 22.033, Mission to Mars
ANDIE
1. Molten salt transfers the heat from the core to the radiator
2. All power is radiated towards TPV collector
3. TEM self powered pumps circulate the molten salt coolant
4. TPV collectors generate DC from thermal radiation
5. Residual heat is dissipated into outer space
Advanced Nuclear Design for Interplanetary Engine
May 15th, 2003 22.033, Mission to Mars
ANDIE Core Physics
Power 11 MWth
Dimensions 202020cm
Total mass 185 kg
Reflector thickness 6 cm (Zr3Si2)
Coolant, molten salt (50:50 NaF-ZrF4)
Fuel, RG Pu carbide, honeycomb
plates
keff BOL = 1.1
Core lifetime 570 FPD
Honeycomb Fuel
ANDIE Core Layout
May 15th, 2003 22.033, Mission to Mars
ANDIE Thermal Hydraulics
• Fuel centerline temperature 1767K
• Core inlet temperature 1550K
• Core outlet temperature 1600K
• Core mass flow rate 249.81 kg/s
• Plate spacing 5.5 mm
• Plate thickness 2.05 mm
• Pressure drop 123 kPa
• Pumping power 11.89 kW (40 kWe)
May 15th, 2003 22.033, Mission to Mars
Internal Radiator
• Radiates 10MW towards TPV collectors
• TPV collectors generate 4 MWe (η=40%)
• Operates at 1575K temperature
• Annular U-tube design 39/35mm outer/inner diameter
• Made of titanium (w/ high emissivity coating)
• U-tube height 15 m
• Radiator weight 2967 kg
• Molten salt weight 1975 kg
May 15th, 2003 22.033, Mission to Mars
Pumps
• TEM pumps from SP-100 program– Thermoelectric Electromagnetic Pump
– Self powered
– Self starting
– Self regulating
– No moving parts
– 10 year operating life
– Designed to operate at 1310-1350K
– Available operating experience
May 15th, 2003 22.033, Mission to Mars
Shielding ANDIE
Radiation Detector
mR/hr
WLiH
W
Ĵo = 8.752 x 1013 n/cm2 s
Neutron Moderation and Absorption: LiHGamma Attenuation: WR
adiator
May 15th, 2003 22.033, Mission to Mars
How much does ANDIE weigh?
Reactor 200 kgShield 3200 kgMolten Salt 1975 kgRadiator 2967 kgArmor + TPV 2100 kgPumps 400 kgTotal Mass 10842 kgSpecific Mass 2.71 kg/kWe
May 15th, 2003 22.033, Mission to Mars
Surface Power Goals
• Sufficient power for all surface applications (i.e. ISRU, habitat etc.)
– ~200 kWe
Objectives Weight25 Years of Operation 29.4%
Low Mass 17.6%
Slow Transients 20.6%
Low Reactivity Swing 8.8%
Chemically Inert in CO2 23.5%
May 15th, 2003 22.033, Mission to Mars
Surface Reactor Decision Problem
• 192 Possible Combinations– Neutron Spectrum: Thermal, Epithermal, Fast– Coolant: CO2, LBE– Reactor Fuel: UO2, UC, US, UN– Matrix Material: BeO, SiC, ZrO2, MgO– Fuel Geometry: Pin, Block
• 4 Decision Options Formulated– Option 1: Epithermal, CO2, UO2, BeO, Block– Option 2: Fast, CO2, US, SiC, Block– Option 3: Fast, LBE, UC, Pin– Option 4: Thermal, CO2, UO2, BeO, Block
May 15th, 2003 22.033, Mission to Mars
Multi-Attribute Utility Theory
PMN
i
ijij uwPI1
optiondecision jth theof PM thi on the Utility Expected
Measure ePerformanc thi on the Weight optiondecision thj theofIndex ePerformanc Expected
ijuiwjPI
Overall Performance Index
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
1 2 3 4
Option
PI
Option 1: Epithermal, CO2, UO2, BeO, BlockOption 2: Fast, CO2, US, SiC, BlockOption 3: Fast, LBE, UC, PinOption 4: Thermal, CO2, UO2, BeO, Block
May 15th, 2003 22.033, Mission to Mars
Surface Power System
• Cooled by Martian atmosphere (CO2)– Insensitive to leaks
• Shielded by Martian soil and rocks– Low mass
• Hexagonal block type core – Slow thermal transient (large thermal inertia)
• Epithermal spectrum– Slow reactivity transient– Low reactivity swing
May 15th, 2003 22.033, Mission to Mars
CADEC
• Pressurized CO2 from atmosphere cools the core
• Direct, closed, recuperated Brayton cycle for electricity production (ηnet~20%)
CO2 cooled Advanced Design for Epithermal Converter
GENERATOR
RECUPERATORPRECOOLER
TURBINECOMPRESSOR
REACTOR
1 2
3
4
5
6
May 15th, 2003 22.033, Mission to Mars
CADEC Core Physics
• Power 1 MWth
• Dimensions L=160 cm, D=40 cm– 37 hexagonal blocks
• Total mass 3800 kg
• Reflector thickness 30 cm (BeO)
• Coolant Martian atmosphere (CO2)
• Fuel 20% enriched UO2 dispersed in BeO
• keff BOL = 1.14
• Core lifetime >25 EFPY
What does CADEC look like?
May 15th, 2003 22.033, Mission to Mars
CADEC Thermal Hydraulics
• System pressure 480 kPa
• Core inlet temperature 486 C• Core outlet temperature 600 C• Core mass flow rate 7.47
kg/s
• Channel diameter 30 mm
• Block flat-to-flat 63 mm
• Film temperature difference 2.5 C• Pressure drop 25 kPa
May 15th, 2003 22.033, Mission to Mars
Shielding CADEC
Martian soilCore
Place for shutters
Thickness (cm) 170 180 190 200 210
Corresponding dose rate, shield surface (mrem/hr)
75.5 31.7 13.3
5.6 2.4
Dose rate (GCR), Martian surface (mrem/hr) > 1.1
May 15th, 2003 22.033, Mission to Mars
Conclusions
•Mission plan
– Technology demonstration
•Reliability assurance before
people are committed
– Long term, reusability strategy
•Reduces recurring costs to
future missions
May 15th, 2003 22.033, Mission to Mars
Conclusions
• ANDIE: Innovations – Molten salt coolant
•Very high temperature, low pressure
– Pre-rejection of heat at high temperature
•Small radiator mass– TPV collector
•High efficiency conversion– Ultra compact core
•Fast spectrum, RG PuC fueled •Potentially reduced shield mass
May 15th, 2003 22.033, Mission to Mars
Conclusions
•CADEC Innovative features– Epithermal spectrum
•Slow kinetics (maintains large βeff)•Enhanced conversion•Compromise between advantages of fast and thermal systems
– CO2 coolant•Local resource•Resistant to leaks or ingress
– Martian soil shield
May 15th, 2003 22.033, Mission to Mars
Conclusions
•CADEC Brayton cycle– Acceptable efficiency (25%)– Open cycle - operation is challenging– Closed cycle - heat rejection is the
weakest point of the design•Massive pre-cooler required
OR•Required fan power is too high (reduces the efficiency to 20%)
– The design requires further optimization
May 15th, 2003 22.033, Mission to Mars
Space Reactor Nuclear Design
• Thermal spectrum: Am242m
• Small fuel mass
• Requires moderator
• Challenging to control
Goals
• Minimize reactor core mass and volume
• Provide 11 MW of thermal power for 3 180 days round trips
• Flat reactivity throughout lifetime
• Controlled by out-of-core mechanisms
Fast spectrum: LWR Grade Pu
Ultra-compact and light
Controlled by direct leakage
Potential for positive reactivity feedback
Options explored
Space Reactor: Thermal Core Moderator Mass
0
5
10
15
20
25
30
35
0 1000 2000 3000 4000 5000 6000
Moderator Mass, kg
Burn
up, a/
o
Am242m - 100%
Am242m:Am241 - 50:50
Am242m:Am241 - 25:75
Am242m:Am241:Pu240 - 25:25:50
Space Reactor: Thermal Core kinf BOL
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
0 10 20 30 40 50 60 70 80
Reactivity Limited Burnup, a/o
Kin
f, B
OL
AM242m-100w/o
AM242m:AM241 - 50:50
AM242m:AM241 - 25:75
AM242m:AM241:Pu240 - 25:25:50
May 15th, 2003 22.033, Mission to Mars
CECR Description
Dimensions L: 160 cm D core: 40 cm D tot: 100 cm
Hexagonal Pitch: 12.6 cm
7 Blocks in Core
3800 kg Total Mass
Volume Fraction (core)
65 v/o Fuel/Matrix
5 v/o Structure
30 v/o Coolant
Control 25 v/o U238 Blanket
30 cm BeO Reflector
1 cm TaB2 Shutter
Fuel Form 30 v/o UO270 v/o BeO
20 % enriched U BOL
10 % Pu239 EOL
May 15th, 2003 22.033, Mission to Mars
Core Physics: Unit Cell Axial Leakage (unreflected)
6.5 % Neutron streaming
Prompt Fission Time ()
6 us Mirror BCs
Delayed Neutron Fraction ()
0.0068 BOL 0.0054 after 40 MWD/kgHM
Reactivity Limited Burnup
Keff = 1.05 at 40 MWD/kgHM
Reactivity Swing:0.13
0 5 10 15 20 25 30
1.04
1.06
1.08
1.10
1.12
1.14
1.16
1.18
1.20
k ef
f uni
t ce
ll
Operation Time [EFPY]
1E-6 1E-5 1E-4 1E-3 0.01 0.1 1 10 100 1000 10000
0.000
0.005
0.010
0.015
0.020
0.025
N
orm
aliz
ed F
lux
Per
Uni
t Le
thar
gy
[BO
L]
Energy (keV)
May 15th, 2003 22.033, Mission to Mars
Core Physics: Whole Core (HOM.)
TaB2 Control Drum Worth
Total:-0.409
Per Drum:-0.0681 (-$10 BOL)
Prompt Fission Lifetime ()
700 us = 5.1 us (BOL)[SAFE 400: 0.0035 us (BOL)]
H2O Immersion +0.124 +$2Designed to have negative feedback with CO2 on Mars