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

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


Outline

•Mission plan

•Decision methodology

•Space power system

•Surface power system

•Conclusions


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


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.)


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


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


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


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.


Electric Propulsion Options

Precursor cargo missionsArray of advanced Ion / Hall thrusters

Power 10 – 80 kW

Isp3000 – 10000 sec

Thrust 1 – 3 N


Electric Propulsion (Manned)

Variable Specific Impulse Magnetoplasma Rocket

– VASIMR -

10 MW of power


Space Power Goals

• Low mass

– <3 kg/kWe

• Scalable

– 200-4000 kWe

• Simple and reliable– No moving parts

• Multiple round trips


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


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


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


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)


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


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


Shielding ANDIE

Radiation Detector

mR/hr

WLiH

W

Ĵo = 8.752 x 1013 n/cm2 s

Neutron Moderation and Absorption: LiHGamma Attenuation: WR

adiator


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


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%


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


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


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


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


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?


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


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


Conclusions

•Mission plan

– Technology demonstration

•Reliability assurance before

people are committed

– Long term, reusability strategy

•Reduces recurring costs to

future missions


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


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


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


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


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


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)


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

Documents

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