Gen IV Nuclear Reactors

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Gen IV Nuclear Reactors
Jasmina VujicProfessor and Chair Department of
Nuclear Engineering University of California,
Berkeley

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The Generation IV Technology Roadmap
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Economics will be strong influenced by design
optimization to increase power while reducing
structures/equipment
Large light water reactors with passive safety
features will be difficult to beat for commodity
electricity generation
Scaled Comparison
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Generation IV Nuclear Energy Systems
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Goals for Gen IV Nuclear Energy Systems

• Sustainability
• provide sustainable energy generation that meets
  clean air objectives and promotes long-term
  availability of systems and effective fuel
  utilization for worldwide energy production
• minimize and manage their nuclear waste and
  notably reduce the long term stewardship burden
  in the future, thereby improving protection for
  the public health and the environment
• Economics
• have a clear life-cycle cost advantage over other
  energy sources
• have a level of financial risk comparable to
  other energy projects
• Safety and Reliability
• operations will excel in safety and reliability
• have a very low likelihood and degree of reactor
  core damage
• eliminate the need for offsite emergency response
• Proliferation Resistance and Physical Protection
• increase the assurance that nuclear systems and
  their fuel cycles are a very unattractive and
  least desirable route for diversion or theft of
  weapons-usable materials, provide physical
  protection against acts of terrorism

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Fuel Cycles for Gen IV Systems
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The Generation IV International Forum has adopted
4 primary goals for new nuclear energy systems

• Economics
• Major drivers reactor capital costs (scale
  economies), operational reliability, additional
  products (hydrogen/actinide management)
• Second-order drivers fuel-cycle, OM and FOAKE
  costs
• Proliferation Resistance and Physical Protection
• Proliferation resistance through global system
  configuration (centralization of fuel cycle
  services) and advanced safeguards
• Physical protection through increased intrinsic
  barriers to theft, hardening of safety systems
  (passive safety), optimization of facility
  physical configuration
• Sustainability
• Improved waste management (efficient use of
  limited repository space), efficient use of
  resources
• Safety and Reliability
• Improved, flexible safety analysis (CSAU, PIRT)
• Optimized reactor operation and maintenance

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GENERATION IV SYSTEMS

• Generation IV Roadmap
• Identifies 6 systems selected by the Gen IV
  International Forum for cooperative development
• Gas-Cooled Fast Reactor System GFR
• Lead-Cooled Fast Reactor System LFR
• Molten Salt Reactor System MSR
• Sodium-Cooled Fast Reactor System SFR
• Supercritical-Water-Cooled Reactor System SCWR
• Very-High-Temperature Reactor System VHTR
• Lays out RD needs and recommendations
• System specific and crosscutting
• Phased viability, performance, demonstration
• US implementation plan calls for emphasis of
• VHTR (top priority)
• Fast spectrum systems

Source U.S. Department of Energy
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Generation IV International Forum
Russia
USA
Switzer-land
South Africa
Korea
Japan
France
Euratom
Canada
China
GIF
Framework
VHTR
GFR
SFR
SCWR
LFR
MSR
GFR - Gas-cooled fast reactor LFR - Lead-cooled
fast reactor MSR - Molten salt reactor SFR -
Sodium-cooled fast reactor SCWR - Supercritical
water-cooled reactor VHTR - Very high temperature
reactor
Framework Signatory
Expected Signatory
Lead or Co-Lead
System Signatory
Potential Signatory
Non-active
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Generation IV Systems Source U.S. Department of
Energy
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Very-High-Temperature Reactor (VHTR)

• Characteristics
• He coolant, direct cycle
• 1000C outlet temperature
• 600 MWth, nominally based on GT-MHR
• Coated particle fuel
• Solid graphite block core
• High thermal efficiency
• Hydrogen production
• Passive safety
• Reactor physics issues
• Fuel double heterogeneity
• Stochastic behavior of pebble movement (for PBR
  variant)
• Graphite scattering treatment

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Gas-Cooled Fast Reactor (GFR)

• Characteristics
• He (or SC CO2) coolant, direct cycle gas-turbine
• 850C outlet temperature
• 600 MWth/288 MWe
• U-TRU ceramic fuel in coated particle,
  dispersion, or homogeneous form
• Block, pebble, plate or pin core geometry
• Waste minimization
• Efficient electricity generation
• Reactor physics issues
• Core configuration dependent
• Neutron streaming
• Data for actinides and fuel matrix candidate
  materials

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Lead-Cooled Fast Reactor (LFR)

• Characteristics
• Pb or Pb/Bi coolant
• 550C to 800C outlet temperature
• U-TRU nitride or Zr-alloy fuel pins on triangular
  pitch
• 120400 MWe
• 1530 year core life
• Core refueled as a cartridge
• Distributed energy generation
• Transportable core
• Passive safety and operational autonomy
• Reactor physics issues
• Data for actinides, Pb, Bi
• Spectrum transition at core edge
• Reactivity feedback coefficients

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Sodium-Cooled Fast Reactor (SFR)

• Characteristics
• Sodium coolant, 550C Tout
• 150 to 1500 MWe
• U-TRU oxide or metal-alloy fuel
• Hexagonal assemblies of fuel pins on triangular
  pitch
• Homogenous or heterogeneous core
• Consumption of LWR discharge actinides
• Efficient fissile material generation
• Reactor physics issues
• Actinide data
• Full-core transport effects
• Spectral transition at core periphery and beyond
• Accurate modeling of expansion feedback

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Supercritical-Water-Cooled Reactor (SCWR)

• Characteristics
• Water coolant at supercritical conditions (25
  Mpa,374 C)
• 510C outlet temperature
• 1700 MWe
• UO2 fuel, clad with SS or Ni-based alloy
• Square (or hex) assemblies with moderator rods
• High thermal efficiency - 44, compact plant
• Thermal or fast neutron spectrum
• Reactor physics issues
• Similar to BWRs
• Increased heterogeneity
• Strong coupling of neutronics and T-H
• Neutron streaming

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Molten Salt Reactor (MSR)

• Characteristics
• Molten fluoride salt fuel
• 700800C outlet temperature
• 1000 MWe
• Low pressure (lt0.5 MPa)
• Circulating actinide-bearing fuel
• Graphite core structure to channel flow
• Actinide consumption
• Avoids fuel development and fabrication
• Reactor physics issues
• Evolution of mobile-fuel composition
• Modeling of nuclear, thermal, and physio-chemical
  processes
• Delayed neutron precursor loss

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Possible NGNP Reactor Configuration
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Why High Temperature Nuclear Process Heat?

• Diversification of energy supply to reduce
  exposure to increasing cost of natural gas and
  petroleum
• Reduced CO2 emissions by leveraging existing
  hydrocarbon reserves through improved
  carbon efficiencies
• Improved economics and hydrocarbon use for
  synthetic fuel production
• High Temperature Process Heat
• Hydrogen production
• Electricity generation
• Downstream operations refining
• Upstream operations tertiary recovery, oil
  sands and oil shale
• Synthetic fuel production from coal
• Chemical industry

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Application of HTGRs in the Future Petroleum
Picture
Upstream
Refining
Tertiary Oil Recovery
Future Refinery
Process Heat
Oil Sands
Process Heat
Oil Shale (Future)
Process Heat H2
Process Heat
Coal to Liquids and Gas
O2 H2
H2 for Onsite Processing
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Nuclear Option Direct Heating To Avoid
Heat-to-Electricity-to-Heat Loses
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700C Heat Hundred year U.S. oil supply from
just shale oil ! Other fossil resources
elsewhere
07-019
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The HTGR is not a new technology
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Escom and Entergy are exploring NRC design
certification of the Pebble Bed Modular Reactor
(PBMR)

• Specifications
• 115 MWe modular high-temperature helium-cooled
  gas-turbine reactor
• Based on 15MWe German AVR that operated from
  1967-1989
• Fuel temperatures
• Average fuel 1095C
• Peak fuel shut-down 1600C
• Maximum tolerable gt2000C
• Uses helium gas turbine (45 thermal efficiency)
• 3.5 m diameter x 10 m high graphite lined vessel
  440,000 6-cm diameter pebbles
• Power controlled by adding or removing helium
  coolantno control rods
• Pebble recycling maintains constant reactivity
  and achieves very high fuel burnup
• Capital cost estimate 1,000/kWe
• Construction time estimate 24 months

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NGNP fuel is capable of operating at high
temperatures
Pyrolytic Carbon
Silicon Carbide
Porous Carbon Buffer
Uranium Oxycarbide
TRISO Coated fuel particles (left) are formed
into fuel rods (center) and inserted into
graphite fuel elements (right).
PARTICLES
COMPACTS
FUEL ELEMENTS
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Upcoming PBMR milestones include start of
prototype construction in 2001, criticality in
2004

• Key attributes
• High power density of gas turbines
• Shutdown heat removal always on--no moving parts
• Very high fuel burn up (15) reduces waste
  generation
• Issues
• Fuel performance
• Confinement vs. containment

10 MWe PBMR at Tsinghua University, PRC First
criticality Dec. 2000
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Pre-Conceptual Design Results
The table below presents a set of preliminary
selections for the NGNP design that are based
Pre-Conceptual Design studies. These preliminary
selections serve as the point of departure for
the NGNP conceptual design effort.
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Public-Private Partnership Model
NGNP Public-Private Partnership

• Direct involvement of commercial end-users,
  technology developers, nuclear system suppliers
  and equipment manufacturers in the Alliance
• Commercial contracting vehicles between the
  Alliance and performing entities
• Contemporary commercial project management
  practices for the design, licensing and
  construction of the demonstration prototype
• Operation of the prototype by an experienced
  commercial nuclear operator

Cooperative Agreement Technology Investment Agre
ement
Commercial Alliance 501(c)(3) Corporation
US Department of Energy
Advisory Group
Management Organization
Architect/ Engineers
Equipment Suppliers
Technology Developers
National Laboratories
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NGNP Hydrogen Production RD

• Hydrogen production
• Sulfur based
• Working toward a lab-scale experiment
• High temperature electrolysis (HTE)
• Completed a 1000 hour test with over 100 l/hr

Examples of several sulfur based thermochemical
cycles
HTE test cell
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ENHS reactor layout

• underground silo
• no pumps
• no pipes
• no valves
• factory fueled
• weld-sealed
• gt20 years core
• no fueling on site
• Module is replaced
• shipping cask
• no DHRS but RVACS

Replaceable Reactor module
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SUSTAINABLE NUCLEAR ENERGY

• Emission-free, safe and reliable nuclear energy
  systems
• Closed fuel cycle - with reprocessing of spent
  fuel
• expand the nuclear fuel supply into future
  centuries by recycling used fuel to recover its
  energy content
• Allow geologic waste repositories to accept the
  waste of many more plant-years of NP operation
  through substantial reduction in the amount of
  radioactive wastes, their decay heat, and
  toxicity
• Proliferation resistant fuel cycles
• Economical and affordable Nuclear Energy
• New simplified modular designs
• Production of Hydrogen, water desalination,
  district heating