Operational Reactor Safety
22.091 /22.903
Professor Andrew C. Kadak Professor of the Practice
Lecture 7 Design Issues
Power Cycles for Nuclear Plants
Topics to be Covered
• Design Issues for nuclear plants Kneif (8,9 10)
• Rankine Cycle
– B a s i c
– S uperheat
– M ulti-fluid cycles
– B rayton cycle
• Pressure Ratios
Reactor Design Interactions
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Department of Nuclear Science & Engineering Page 3
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Reactor Core Design
• Thermal Analysis
– Set inlet and outlet temperature
– Assume radial peaking factor to calculate hot channel coolant temperature
– Assume axial flux profile and engineering factors to calculate hot channel coolant temperature
– Calculate clad surface temperature profile for hot channel assuming a clad surface heat flux and empirical heat transfer coefficient
Design Process (2)
– Set clad and gap conductance materials and dimensions
– Calculate fuel surface temperature profile
• Fuel Pin Composition and diameter selection
– For a given fuel material use thermal conductivity and peak temperature to determine limiting heat rate for hot channel
– Set pellet diameter based on fuel fabrication cost
– Recalculate heat fuel and temperature
Reactor Design (3)
• Core sizing
– Calculate number of fuel pins from core power and length
– Chose geometry and spacing
– Calculate physics parameters – axial and radial power profiles
– Assess safety (reactivity coefficients) and power conversion factor (core lifetime)
– Calculate required coolant velocity
Reactor Design (4)
• Fuel Cycle Economic Analysis
• Fuel Pin Structural Analysis
• Hydraulic Analysis
– P ressure drops, flow distributions
– P umping power requirements
• Safety Analysis
– R eactivity coefficients for accident analysis
• Fuel element reliability analysis – fuel stress etc.
• Post Irradiation handling considerations – cooling needs
Fuel Performance
Prof. Andrew C. Kadak,
& Engi ing
2008
Department of
Fuel Designs for LWRs
BWR Fuel Assembly
PWR Fuel Assembly
Fuel Rod Design Interactions
Typical Protective System
Department o
ak, 2008
Prof. Andrew C. Kad
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Daya Bay PWR – French Design
Schematic of Plant Design
Key Reactor Systems
• Reactor Coolant System
• Heat Removal Systems
• Nuclear Support Systems
• Plant Service Systems
• Nuclear Safety Systems
• Balance of Plant
Power Conversion Systems
Temperature Entropy Diagrams
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Department of Nuclear Science & Engineering Page 21
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me
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Basic Rankine Cycle
Steam Generators
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Department of Nuclear Science & Engineering Page 24
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Rankine Cycle with Feedwater Heaters
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Department of Nuclear Science & Engineering Page 25
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Power Cycles
Binary Cycle Plants
Gas Reactor Cycles
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Department of Nuclear Science & Engineering Page 29
Brayton Gas Cycle - O pen
Perfect Gas Relationships
Indirect Brayton Open Cycle
Direct Closed Brayton Cycle
Indirec t Close d Cycl e – Ga s t o G as
Indirect Gas to Steam Generator
Specific Heats of Gases
Ideal Brayton Cycle
Non-Ideal Brayton Cycle
Gas-Steam Reactor Power Plant
Departm
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e
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Depart
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me
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Departme
, 2008
Prof. Andrew C. Kadak
nt
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Reading and Homework
Assignmen t
1. Read Knief Chapter 8, 9, 10
2. Outside Reading El-Wakil Chapter 2
3. Problems 2.7, 7.4
Prof. Andrew C. Kadak, 2008
Department of Nuclear Science & Engineering Page 44
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22.091 Nuclear Reactor Safety
Spring 200 8
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