Post on 12-Dec-2021
Advanced High-Temperature Reactors: What and Why
(A Story of Technology Development)
Charles W. Forsberg
Oak Ridge National Laboratory*P.O. Box 2008; Oak Ridge, TN 37831-6165
Tel: (865) 574-6783; e-mail: forsbergcw@ornl.gov
Oak Ridge Institute of Continued Learning (ORICL)A Program of Roane State Community College; Oak Ridge Campus
Oak Ridge, TennesseeFebruary 3, 2006
*Managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. The submitted manuscript has been authored by a contractor of the U.S. Government under contract DE-AC05-00OR22725. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to
publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes. File name: ORICL.Feb06
High Temperature ReactorsProduce Heat at Temperatures
above 700ºC (1300ºF)
THTR(FRG)
1986 - 1989
FORT ST. VRAIN(U.S.A.)
1976 - 1989
PEACH BOTTOM 1(U.S.A.)
1967 - 1974
AVR(FRG)
1967 - 1988
DRAGON(U.K.)
1963 - 76
EXPERIMENTAL REACTORSDEMONSTRATION OF
BASIC HTGR TECHNOLOGY
And Then They Were Abandoned…
High-Temperature Helium-Cooled Reactors were Partly Developed
High-Temperature Reactors are BackA Story of Changing Needs and New Technologies
• New needs and technologies− Efficient electricity
production− Liquid fuels− Limited water consumption
• New high-temperature reactor technologies− Gas-Turbine High-
Temperature Helium Reactor− The Advanced High-
Temperature Reactor
Electricity ProductionA New Technology Makes an Old Technology Useful by More Efficiently Converting High-Temperature Heat to Electricity
Brayton Power (Jet Engine) Cycles may Make High-Temperature Reactors Viable
(Helium or Nitrogen Brayton Power Cycles)
• High-temperature heat is only useful if it can be converted to electricity
• Steam turbines, the traditional heat-to-electricity technology, have historically had a temperature limit of ~ 550ºC
• New Brayton cycles can efficiently convert high-temperature heat to electricity and makes high-temperature reactors more useful
• Boost heat-to-electricity efficiency from 40 to 50%
GE Power Systems MS7001FB
General Atomics GT-MHR Power Conversion Unit (Russian Design)
05-021
The Age of Oil for Fuels is Closing
1900 1920 1940 1960 1980 20000
10
20
30
40
50
60
0
10
20
30
40
50
60
Dis
cove
ries
(bill
ion
bbl/y
ear)
Prod
uctio
n (b
illio
n bb
l/yea
r)
Discovery
Consumption
Oil and Gas J.; Feb. 21, 2005
Conventional Futures: Liquid Fuels will be Made from Heavy Oils and Tar Sands
(Lower Hydrogen-to-Carbon Ratios)
• Tar sands and heavy oils are converted to liquid fuels by:− Addition of hydrogen
− Removal of carbon (usually with CO2 to atmosphere)
• Implies massive increase in H2 demand
• Traditional technologies imply major increases in CO2 releases per vehicle mile (greenhouse-gas concern)
Syncrude Canada Ltd. Tar Sands Operations
Conventional Futures Imply Rapidly Increasing Greenhouse Emissions per
Vehicle Mile Traveled
05-055R
Illinois #6 Coal Baseline
Pipeline Natural Gas
Wyoming Sweet Crude Oil
Venezuelan Syncrude
0
200
400
600
800
1000
1200
Gre
enho
use
Impa
cts
(g C
O2-
eq/m
ile in
SU
V)
Conversion/RefiningTransportation/Distribution
End Use CombustionExtraction/Production
Business As Usual
Using Fuel
Making and
Delivering of Fuel
(Fisher-TropschLiquids)
(Fisher-TropschLiquids)
Source of G
reenhouse Impacts
The Electric-Liquid Fuel Future(New Roles for High-Temperature Reactors)
• Plug-in hybrid cars and light trucks
• Hydrogen-rich liquid fuels
Strategy I: Hybrid Engines Enable Plug-In Hybrid Electric Vehicles (PHEVs)
(Recharge Batteries when Vehicle Not in Use)• Electric cars have two major
battery-connected limitations− Limited range− Recharge time (gasoline refueling rate
is ~10 MW) • Advanced hybrid vehicle option
− Electric drive for short trips− Hybrid (gasoline and electricity) for
long trips− Recharge battery over night (plug in)
• Reduction in oil consumption• Alternative to the strategic
petroleum reserve• Cuts greenhouse emissions by
using clean electric sources
Courtesy of the Electric Power Research Institute
Prototypes in the Field
PHEV Annual Gasoline ConsumptionConnecting Transportation to the Electric Grid
Compact Sedan
Midsize Sedan
Midsize SUV
Fullsize SUV
-
100
200
300
400
500
600
700
800
900
Ann
ual G
asol
ine
Con
sum
ptio
n (g
allo
ns)
Conventional Vehicle"No-Plug" HybridPlug-in HEV, 20 mile EV rangePlug-in HEV, 60 mile EV range
Courtesy of the Electric Power Research Institute
05-074
Strategy II: Hydrogen for Increasing Liquid Fuel per Unit of Feedstock and Reduce Emissions
Fossil Feedstock
(Oil,Tar Sands,
Coal)
Refinery
Furnace
Heat
H2 and O2
Nuclear Hydrogen
Refinery
Furnace
Heat
H2
HydrogenProduction
Carbon
Carbon
Liquid Fuel
Liquid Fuel
Carbon Dioxide
Releasesto
Atmosphere
TransportServices
TransportServices
Current Approach
FutureApproach
Synergistic Fossil and Nuclear H2
All Fossil Carbon Converted to Liquid Fuels No Carbon Release from Fuel Production
Hydrogen sources: nuclear, renewables, and coal with carbon dioxide sequestration
Zero-Greenhouse-Gas Liquids Fuel Strategy
06-007
Near-Term• Biomass• Trash• Sewage
Refinery
Furnace
Heat
Hydrogen
Nuclear Hydrogen
Carbon
Liquid Fuel
TransportServices
Non-FossilCarbon
Feedstock
• Cement Production
• Air• Seawater
Long-Term
Carbon Dioxide
Releasesto
Atmosphere
(Transition to longer-term liquid fuels; creates infrastructure for direct use of hydrogen if that technology is successful)
Recycle From Atmosphere or Intercept CO2 To Atmosphere
Nuclear H2 Production Options(An Incentive for Developing High-Temperature Reactors)
TodayInput: Electricity
ElectrolysisElectricity + 2H20 → 2H2 + O2
High-Temperature ElectrolysisElectricity + 2H20 (Steam) → 2H2 + O2
Hybrid CyclesHeat + Electricity + 2H20 → 2H2 + O2
Thermochemical CyclesHeat + 2H20 → 2H2 + O2
FutureInput: Lower cost high-
temperature heat
04-083
High-Temperature Reactors Reduce Water Requirements and Enable
Dry Cooling
30 35 40 45 60500
0.5
1.0
1.5
2.0
2.5
Hea
t Rej
ectio
n (k
W(t)
/kW
(e)
Efficiency55
Existing Reactors
High Temp Reactors
Cut Cooling Demand in Half
→ →
Dry Cooling for Electricity Generation
Thermal Power Plant Dry Cooling(ACC at PacifiCorp’s Wyodak Power Plant (Courtesy of R. Garan)
High-Temperature Reactors
Efficient Electricity ProductionHydrogen Production
Minimal Water Consumption
Two Types of High-Temperature Reactors are Being Developed(MHTGR Near-term; AHTR Midterm)
Modular High-Temperature Gas-Cooled Reactors
Gas-Cooled: 600 MW(t); Near-Term Option
81m70m
Advanced High-Temperature ReactorLiquid-Salt-Cooled: 2400 MW(t)
Longer-term Option
Per Peterson (Berkeley): American Nuclear Society 2004 Winter Meeting
Both Reactor Concepts Use the Same Fuel Type
• Coated-particle graphite-matrix fuel
• Only demonstrated high-temperature fuel
• Two fuel variants− Hexagonal block
(shown)− Pebble bed
• Peak operating temperature: 1250ºC
Only Two Reactor Coolants areChemically Compatible with Graphite-
Matrix Fuel(Two Reactor Options Based on Choice of Coolant)
Helium(High Pressure/Transparent)
Liquid Fluoride Salts(Low Pressure/Transparent)
Modular High-Temperature Gas-Cooled Reactor
Advanced High-Temperature Reactor
The Advanced High-Temperature Reactor
Combining Different Technologies in a New Way
New Concept Being Developed at ORNL(Partnerships with Framatome, University of California at Berkeley,
University of Wisconsin, Argonne National Laboratory, Sandia National Laboratory, and Idaho National Laboratory)
Passively Safe Pool-Type Reactor Designs
High-Temperature Coated-Particle
Fuel
The AdvancedHigh-Temperature
Reactor Combining Four Existing
Technologies in a New WayGeneral Electric
S-PRISM
High-Temperature, Low-Pressure
Transparent Liquid-Salt Coolant
Brayton Power Cycles
GE Power Systems MS7001FB
There is Significant Experience with Molten and Liquid Fluoride Salts
Good Heat Transfer, Low-Pressure Operation, and Transparent (In-Service Inspection)
Liquid Fluoride Salts were Used in Molten Salt Reactors with Fuel in Coolant
(Molten Salt Reactor Experiment)
Molten Fluoride Salts are Used to Make Aluminum in Graphite Baths at 1000°C
The AHTR Uses Coated-Particle Fuel(Peak Operating Temperature: 1250ºC; Failure Temperature: >1600ºC)
Same Fuel Originally
Developed for Gas-Cooled High-
Temperature Reactors
2400 MW(t)
Brayton Power Cycles Convert the Heat to Electricity
(Helium or Nitrogen Brayton Power Cycles)• Developed from
aircraft jet engines• Required 50 years of
development before useful for the utility industry
• Electric utility needs− Reliability: Measured
in years, not 1000s of hours as for aircraft
− Cost is controlling. Economics, not performance (military) is the first requirement
GE Power Systems MS7001FB
General Atomics GT-MHR Power Conversion Unit (Russian Design)
AHTR Facility Layouts are Based on Sodium-Cooled Fast Reactors
Low Pressure, High Temperature, Liquid Cooled
General Electric S-PRISM
Schematic of Advanced High-Temperature Reactor
• 705ºC: 48.0%• 800ºC: 51.5%
Efficiency Depends upon Temperature
Liquid Cooling Allows Large Reactors with Passive Decay Heat Removed
05-023
Core
Alternative Decay Heat Removal Options to Move Heat to Vessel Surface or Heat Exchanger
Liquid(1000s of MW(t))
Gas(~600 MW(t))
Convective Cooling(~50º C Difference in Liquid Temperature)
Conduction Cooling(~1000º C Difference in Fuel Temperature)
• Passive decay-heat removal systems can remove heat from:− Vessel wall
− Liquid coolant
• Passive decay-heat removal limited by heat transport from fuel to vessel or heat exchanger− Gas-cooled reactor:
Conduction heat transfer: limited heat removal
− Liquid-cooled reactor: Convective heat transfer: no power limit
Coolant Properties Impact Reactor Size and Cost
(Determine Pipe, Valve, and Heat Exchanger Sizes)
03-258
10001000540320Outlet Temp (ºC)
67566Coolant Velocity (m/s)
0.697.070.6915.5Pressure (MPa)
Liquid SaltHeliumSodium (LMR)
Water (PWR)
Number of 1-m-diam. pipes needed to transport 1000 MW(t)
with 100ºC rise in coolant temperature
Reactor Comparison of Building Volume, Concrete Volume, and Steel Consumption Based on Arrangement Drawings
(High-Temperature Reactors are Potentially Competitive Sources of Energy)
Per Peterson (Berkeley): American Nuclear Society 2004 Winter Meeting
0.00
0.50
1.00
1.50
2.00
2.50
1970sPWR
1970sBWR
EPR ABWR ESBWR GT-MHR AHTR-IT
Building volume (relative to 336 m3/MWe)Concrete volume (relative to 75 m3/MWe)Steel (relative to 36 MT/MWe)
Non-nuclear input
Nuclear input
1000 MWe 1000 MWe 1600MWe 1350 MWe 1550 MWe 286 MWe 1235 MWe
←Near-Term Options→
Midterm Option
Conclusions• Technology options are created by
new technologies and new needs• High-temperature reactor rebirth
driven by three factors− New method to efficiently convert
heat to electricity− Need for liquid fuels− Need to reduce water consumption
while producing electricity• Two high-temperature reactor
options− Helium cooled (near-term)− Liquid-salt cooled (longer-term)
• The path to any new technology is long and complicated
• The AHTR was originated at ORNL and is one new direction for nuclear energy