Basic Reactor Systems

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Basic Reactor Systems

• Dr. Steve Reese
• NE 113

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Purposes of Reactors

• Generate electricity
• Propulsion
• Isotope production
• Research

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Reactor Classification

• Energy
• - Thermal (lt 0.1 eV)
• - Fast (0.1 - 2 MeV)
• Moderator
• - Light Water (H2O)
• - Heavy Water (D2O)
• - Graphite (C)
• Coolant
• - Light Water (H2O)
• - Heavy Water (D2O)
• - Liquid Metal (Na)
• - Gas (He)

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Numbers Worldwide

• 233 PWRs
• 87 BWRs
• 29 HWRs
• 4 LMRs
• 20 LGRs

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The Big Picture - PWR
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The Big Picture - BWR
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Containment Building

• Contains all the components of the primary system
• Contain 60 psi over-pressure

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Containment Building
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Primary Coolant Systems

• Reactor Vessel
• Pressurizer
• Steam Generators
• Primary Pumps

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Primary Coolant SystemsReactor Vessel
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Primary Coolant SystemsSteam Generators

• Three Types
• - Once-through
• - Horizontal U-tube
• - Vertical U-Tube
• 3000 Tubes
• 80ºC heat transfer
• Steam collected and dried at the top

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Primary Coolant SystemsSteam Generators
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Primary Coolant SystemsPressurizers

• Heating elements at the base turn water to steam
• Maintain pressure at 2200 psi in a PWR
• Spray nozzle at top reduces pressure
• Power Operated Relief Valve (PORV)

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Mechanical Systems

• Turbines
• Condenser
• Feedwater
• Cooling Towers

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Mechanical Systems Turbines

• Convert high-pressure steam into mechanical
  energy
• Shaft is connected to the generator
• Typically, steam first passes through a small
  high pressure turbine followed by three
  low-pressure turbine

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Mechanical Systems Turbines
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Mechanical Systems Condenser

• One for each low pressure turbine
• Removes (condenses) steam from the turbines
• Cleaning each of the thousands of tubes is
  tedious but important

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Mechanical Systems Cooling Towers

• Two types
• - natural draft
• - mechanical draft
• Natural draft depend on convection currents and
  the venturi effect
• Mechanical draft depend on cooling fans

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Mechanical Systems Feedwater Pumps

• Pumps the water from the condensers back to the
  primary loop
• Just to give an idea of the scale...

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Mechanical Systems Cooling Towers
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Electrical Systems

• Generators
• Substation
• Emergency Generators

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Electrical SystemsGenerators

• Supplies AC power to the grid
• 22 KV
• 50-60 Hz
• Step-up transformer raises the voltage to 220 KV

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Electrical SystemsSubstation and Diesel
Generators
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Control Room
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PWRs Only

• Control rods in the form of pins penetrating the
  top of the core
• Primary loop never leaves containment
• Uses steam generators, adding an extra loop in
  the heat transfer process from fuel to turbine

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Typical PWR Design ParametersReactor and Primary

• Plant life (yrs) 40
• Operating Pressure (psi) 2200
• Total Water Volume (ft3) 12,612
• Primary flow (gpm) 88,500
• Reactor Vessel Inlet Temp (F) 545
• Reactor Vessel Outlet Temp (F) 610
• Primary inlet Pipe Diameter (in.) 28
• Primary Inlet Pipe wall Thickness (in.) 2.7

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Typical PWR Design ParametersPressure

• Hydrostatic Test (psi) 3110
• Design Pressure (psi) 2485
• Power Relief Valves (psi) 2335
• Operating Pressure (psi) 2250
• Low Pressure Trip (psi) 1800

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Typical PWR Design ParametersFuel (Trojan)

• Fuel assemblies 193
• Fuel Rods per Assembly 263
• Number of Pellets per Rod 271
• Total Fuel Rods 50,952
• Total Fuel Pellets 13,807,992
• Cost per Fuel Pellet 2.32

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Excellent Web Sites

• The Virtual Nuclear Tourist
• http//www.cannon.net/gonyeau/nuclear/index.htm
• Todds Atomic Home Page
• http//neutrino.nuc.berkeley.edu/neutronics/todd/
  frame/