Transcript 22.033 Mission to Mars Design Presentation

22.033 Final Design Presentation
Vasek Dostal
Knut Gezelius
Jack Horng
John Koser
Joe Palaia
Eugene Shwageraus
And Pete Yarsky
With the Help of
Kalina Galabova
Nilchiani Roshanak
Dr. Kadak
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
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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 missions
Array of advanced Ion / Hall thrusters
May 15th, 2003
Power
10 – 80 kW
Isp
3000 – 10000 sec
Thrust
1–3N
22.033, Mission to Mars
Electric Propulsion (Manned)
Variable Specific Impulse
Magnetoplasma Rocket
– VASIMR 10 MW of power
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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
Advanced Nuclear Design for Interplanetary Engine
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
May 15th, 2003
22.033, Mission to Mars
ANDIE Core Physics
Power 11 MWth
Dimensions 202020cm
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
May 15th, 2003
22.033, Mission to Mars
Honeycomb Fuel
ANDIE Core Layout
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
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22.033, Mission to Mars
Shielding ANDIE
Neutron Moderation
and Absorption:
LiH
Gamma Attenuation: W
R
a
d
i
a
t
o
r
Radiation Detector
mR/hr
Ĵo = 8.752 x 1013 n/cm2 s
W
May 15th, 2003
LiH
22.033, Mission to Mars
W
How much does ANDIE weigh?
Reactor
Shield
Molten Salt
Radiator
Armor + TPV
Pumps
Total Mass
Specific Mass
May 15th, 2003
200
3200
1975
2967
2100
400
10842
2.71
22.033, Mission to Mars
kg
kg
kg
kg
kg
kg
kg
kg/kWe
Surface Power Goals
• Sufficient power for all surface applications
(i.e. ISRU, habitat etc.)
– ~200 kWe
Objectives
Weight
25 Years of Operation
29.4%
Low Mass
17.6%
Slow Transients
20.6%
Low Reactivity Swing
Chemically Inert in CO2
May 15th, 2003
22.033, Mission to Mars
8.8%
23.5%
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
–
–
–
–
May 15th, 2003
Option 1:
Option 2:
Option 3:
Option 4:
Epithermal, CO2, UO2, BeO, Block
Fast, CO2, US, SiC, Block
Fast, LBE, UC, Pin
Thermal, CO2, UO2, BeO, Block
22.033, Mission to Mars
Multi-Attribute Utility Theory
PI j 
N PM
w u
i 1
i
ij
PI j  Expected Performance Index of the jth decision option
w  Weight on the ith Performance Measure
i
uij  Expected Utility on the ith PM of the jth decision option
May 15th, 2003
22.033, Mission to Mars
Overall Performance Index
0.8
0.7
0.6
PI
0.5
0.4
0.3
0.2
0.1
0
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
1
2
3
Option
4
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
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22.033, Mission to Mars
CADEC
CO2 cooled Advanced Design for Epithermal Converter
5
• Pressurized CO2
from atmosphere
cools the core
COMPRESSOR
1
• Direct, closed,
recuperated
Brayton cycle for
electricity
production
(ηnet~20%)
May 15th, 2003
TURBINE
GENERATOR
2
4
6
PRECOOLER
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3
RECUPERATOR
REACTOR
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
May 15th, 2003
22.033, Mission to Mars
What does CADEC look like?
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
May 15th, 2003
25 kPa
22.033, Mission to Mars
Shielding CADEC
Core
Martian soil
Place for shutters
Thickness (cm)
170
180
190
Corresponding dose rate,
shield surface (mrem/hr)
75.5 31.7 13.3 5.6
Dose rate (GCR), Martian surface (mrem/hr)
May
15th,
2003
22.033, Mission to Mars
200 210
2.4
> 1.1
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
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
Options explored
• Thermal spectrum: Am242m
Fast spectrum: LWR Grade Pu
• Small fuel mass
Ultra-compact and light
• Requires moderator
Controlled by direct leakage
• Challenging to control
May 15th, 2003
Potential for positive reactivity
feedback
22.033, Mission to Mars
Space Reactor: Thermal Core Moderator Mass
35
Am242m - 100%
Am242m:Am241 - 50:50
30
Am242m:Am241 - 25:75
Burnup, a/o
25
Am242m:Am241:Pu240 - 25:25:50
20
15
10
5
0
0
1000
2000
3000
Moderator Mass, kg
4000
5000
6000
Space Reactor: Thermal Core kinf BOL
AM242m-100w/o
2.4
AM242m:AM241 - 50:50
2.2
AM242m:AM241 - 25:75
AM242m:AM241:Pu240 - 25:25:50
Kinf, BOL
2.0
1.8
1.6
1.4
1.2
1.0
0
10
20
30
40
50
Reactivity Limited Burnup, a/o
60
70
80
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 65 v/o
(core)
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 UO2
70 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 (L)
6 us
Mirror BCs
Delayed Neutron
Fraction (b)
0.0068 BOL
0.0054 after
40 MWD/kgHM
Reactivity Limited Keff = 1.05 at
Burnup
40 MWD/kgHM
May 15th, 2003
22.033, Mission to Mars
Reactivity Swing:
0.13
1.20
1.18
1.16
keff unit cell
1.14
1.12
1.10
1.08
1.06
1.04
0
5
10
15
20
Operation Time [EFPY]
25
30
Normalized Flux Per Unit Lethargy [BOL]
0.025
0.020
0.015
0.010
0.005
0.000
1E-6
1E-5
1E-4
1E-3
0.01
0.1
1
Energy (keV)
10
100
1000 10000
Core Physics: Whole Core
(HOM.)
TaB2 Control
Drum Worth
Total:
-0.409
Per Drum:
-0.0681 (-$10 BOL)
Prompt Fission
Lifetime (L)
700 us
bL = 5.1 us (BOL)
[SAFE 400: 0.0035 us (BOL)]
H2O Immersion
+0.124
+$2
Designed to have negative
feedback with CO2 on Mars
May 15th, 2003
22.033, Mission to Mars