John Rawls - US Nuclear Waste Technical Review Board

Implications for Waste Handling of the
Energy Multiplier Module
by
John Rawls
June 29, 2010
132-10/rs
1

Changing the Game for Nuclear Energy
Key National Issues
1. Economics
2. Used Nuclear Fuel
3. Non-Proliferation
4. Energy Security
5. Human Dimension
EM 2 Goals
– To reduce capital investment and
power cost by 30% compared to ALWRs
– To consume & reduce used nuclear fuel
inventory, i.e. minimize need for long-term
repositories
– To reduce need for uranium enrichment;
eliminate conventional fuel reprocessing
– To advance electrification through siteflexibility
& process heat applications;
to reduce foreign energy imports
– To attract eager young minds to a
challenging new enterprise
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EM 2 is a Fast Gas-Cooled Reactor in which Fuel is
Made and Burned in situ
Schematic EM 2 core
control drum
fertile
starter
reflector
Argonne National Laboratory
predicted longer core life and
lower excess reactivity
k-effective
1.15
1.10
1.05
1.00
0.95
0.90
0.85
Basics of the breed and
burn in situ approach
• A starter region containing fissile
material provides initial criticality
• The burn spreads to the fertile region,
where it is sustained by newly bred fuel
• The geometrical arrangement has low
excess reactivity for decades, improving
fuel utilization and simplifying control
EM 2 core reactivity
0 10 20 30 40
Time (Yr)
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Reactor Concept
Point design features
• 500 MWt, He cooled at 850 o C outlet
suitable for process heat applications
• 240 MW e at ~48% net efficiency (~45%
with dry cooling), at power cost
comparable to natural gas at $7/Mbtu
Grade
Power
Conversion
Module
• Burns used LWR fuel w/o reprocessing
(also DU, natural U, WPu, Th admixture)
• 30 + -yr core w/o refueling or reshuffling;
EOL core can be recycled with 30-60%
fission product removal
• Passively safe, underground sited
• Modules factory manufactured &
shipped by commercial trucks
18 m
5 m
Reactor
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Core Composition and Arrangement
Fuel Elements
(typ. of 21 per
layer)
Reactor
Return Flow
Annulus
Core Barrel
Reactor
Vessel Wall
5.0 m (15.6 ft)
B4C Layer
(100 mm
thickness)
Graphite
Reflector Layer
(500 mm
thickness)
BeO Layer (250 mm
minimum thickness)
Material irradiation data is encouraging about the life of SiC structure
Fuel Element
17,136 units
SiC-SiC
clad
porous UC
plate
SiC-SiC Assembly
Frame
Positions plates
for cooling & FP
control
Fuel Assembly
357 units
• Handling unit
• Stackable
• Transfers fission gas
5.19kg
Fission gas
movement
Fission gas
movement
257kg
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Used Nuclear Fuel/DU and Partial Closing of
the Fuel Cycle
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Energy Security: Fuel Utilization 1 Improves with
Number of Cycles
50%
45%
Fuel Utilization
40%
35%
30%
25%
20%
EM 2 First Cycle:
2X LWR Utilization
SNF waste
U.S. SNF inventory: 61,000 t
15%
2
U.S. DOE NE Goal: 10%
10%
5%
0%
LWR 0.5%
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Number of EM 2 Cycles
1
Percent of mined heavy metal that is fissioned 2
U.S. Department of Energy, Nuclear Energy
DU waste
U.S. DU inventory: 700,000 t
Energy in U.S. SNF & DU
inventory is 5 x world’s
proven oil reserves
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Quantity of Waste Produced
Waste (tonnes)
12000
10000
8000
6000
4000
2000
0
-2000
LWR
EM 2
0 100 200 300 400
Waste vs years of operation for a
continuously operating1.2 GWe plant
Impact on repository sizing
(stated on a per unit energy
supplied basis)
• Higher burnup and higher
efficiency mean lower end of
life fuel mass & volume
• These amounts are reduced
further (linearly) by the
number of times fuel is reused
• These figures of merit are
further improved if spent LWR
fuel is used as fuel
Total waste in 400 years: LWR 12,000t, EM 2 < 400t
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Implications for Nuclear Waste
1.E+07
EM 2 Decay After 30-year Burnup
1.E+05
EM 2 Core Decay Heat After 30-year Burnup
Actinides
Fission Products
1.E+04
Decay Activity (Curies)
1.E+06
1.E+05
1.E+04
Decay Energy (Watts)
1.E+03
1.E+02
1.E+01
Actinides
Fission Products
1.E+00
1.E+03
1.E-01
1 10 100 1000 10000
1 10 100 1000 10000
Decay Time (years)
Decay Time (years)
__________________________________________________________________________________________
FP radiological data
• FP makeup quite similar to that of LWRs except
that Cs is removed from the core during the burn
• After 300 yrs, primary FPs are 99 Tc & 151 Sm, two
weak beta emitters; FP heat load is few W/core
Actinide radiological data
• If restricted to one burn cycle, actinide content
per unit energy produced is similar to that of LWRs
and is reduced linearly with the number of cycles
• Long core residence postpones repository need
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Non-Proliferation
Dry cask storage
1. Reduces fuel handling and eliminates long-term
storage of spent fuel containing significant Pu.
Uranium enrichment
2. Eliminates need for conventional reprocessing
(heavy metal chemical separation).
3. Both discharged and refabricated EM 2 fuel
meets self-protection requirements for 20 yrs.
Geological repositories
4. Below-grade reactor core is inaccessible without
special remote handling equipment.
5. Low excess reactivity- core cannot be easily
reconfigured for material insertion/extraction
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10
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Comparative Power Generation Costs
30% cost reduction is a result
of the following attributes
• Less materials
• Factory labor
• Shorter construction time
• Smaller facility footprint
• Higher efficiency
• Decades of life —
no refueling/no shuffling
• Simple control
• Bankablility of fuel
ALWR, coal and natural gas data source: MIT 2009 Cost Update; EM 2 model estimate.
All power generation costs evaluated for a 30-yr levelization period
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DOE-NE Comprehensive EM 2 Peer Review
- Core physics and depletion
- Core thermal hydraulics
- Fuels
- Fission product transport
- Used fuel management
- Structural materials
- Balance of plant
- Safety
- Non-proliferation
- Cost/economics
Key findings:
• Most significant risks are associated with 30-yr core in fast neutron fluence, including
fuel thermal-chemical performance and dimensional stability, SiC clad integrity, and
fission product transport
• Report affirms the reactor physics design and that EM 2 supports all five DOE-NE goals
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185-09/RWS/rs

GA’s Internally-Funded Program Addresses
Fuel and Power Conversion
CY2010 GA-Funded Work
UC Lab
- Bench-scale UC fab facility
- Bench-scale SiC fab facility
- Fuel fab process optimization
- Physics methods upgrade
- Reactivity control design
- EM 2 fuel metrology lab
- High-speed generator
- High-voltage inverter
- Reactor concept optimization
- Power conversion design
- Selected accident analyses
- FP transport component fab
SiC Composite Lab
SiC coater
High-speed
Gas Turbine
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Summary
• Significant capital & power cost reduction
• Reduces (and potentially consumes) the used
nuclear fuel inventory, thereby easing repository
requirements and possibly delaying their need
• Reduces long-term need for enrichment;
eliminates need for conventional reprocessing
• Formidable technical challenges are attracting
eager young minds to a new nuclear enterprise
with a long-term future
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Backup Slides
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EST Also Offers Promise for Used Nuclear Fuel
Fission Products
Heavy Metals
• Uses mass gap between actinides and lanthanides
• Separation of trivalent actinides and lanthanides considered to be the
most difficult current reprocessing steps
– Necessary for both repository management and recycled fuel
• Filter throughput 30X less than wastes much smaller size plant
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EST Technology Proof of Principle has Occurred
• Physically separates based on mass/charge using electromagnetic fields
• Advantages for nuclear wastes
– Relatively indifferent to
waste complexity
– Excellent separation efficiency
– Single step process
– Reduced waste streams
– Significant net cost savings
and risk reduction
• Advantages for used nuclear fuel processing
– Separates fission products
– Not capable of TRU separation by element or isotopes
– Supportive of new reprocessing-free closed fuel cycle options
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Technology Needs & Research Challenges
• Efficient and effective separation of fission products
from reactor discharge
• Understanding properties of materials under high
neutron fluences and high temperatures
• Behavior of fuel and fission products over decades
• Defining and establishing manufacturing base to
realize the cost-effective fabrication of modular
reactors like EM 2
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EM 2 is More Proliferation-Resistant than
Alternative Reactor Concepts
Portion of
Fuel Cycle
Attribute of
Fuel Cycle
Light Water
Reactor
Traditional
Fast Reactor
EM 2
Front end Need for enrichment? Yes
Gen 1: yes
Gen 2: no
Gen 1: yes
Gen 2: no
Operations
Fuel residence time
Sealed vessel?
< 5 yr
No
< 5 yr
No
> 30 yr
Yes
Back end Planned reuse of fuel None
Yes, with Pu
separation
Yes, without
Pu separation
Proliferation vulnerability legend
LOW MODERATE HIGH
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