3. Core Thermal-Hydraulics

• 3.1. Introduction
• 3.2. SAS4A/SASSYS‑1 Channel Approach
  • 3.2.1. Axial Mesh Structure
  • 3.2.2. Radial Mesh Structure
• 3.3. Pre-boiling Transient Heat Transfer, Single Pin Model
  • 3.3.1. Core and Axial Blankets
  • 3.3.2. Reflector Zones
  • 3.3.3. Gas Plenum Region
  • 3.3.4. Order of Solution
  • 3.3.5. Melting of Fuel or Cladding
  • 3.3.6. Coolant Inlet and Re-entry Temperature
• 3.4. Steady-State Thermal Hydraulics
  • 3.4.1. Basic Equations
  • 3.4.2. Coolant Temperatures
  • 3.4.3. Fuel and Cladding Temperatures in the Core and Axial Blankets
  • 3.4.4. Structure Temperatures in the Core Axial Blankets
  • 3.4.5. Reflector, Structure, Cladding, and Gas Plenum Temperature Outside the Core and Axial Blankets
• 3.5. Transient Heat Transfer after the Start of Boiling
  • 3.5.1. Fuel and Cladding Temperatures in the Core and Axial Blanket
  • 3.5.2. Structure Temperatures
  • 3.5.3. Reflector Temperatures
  • 3.5.4. Gas Plenum Region
  • 3.5.5. Coolant Temperatures in Liquid Slugs
• 3.6. Fuel-Cladding Bond Gap Conductance
• 3.7. Fuel Pin Heat-transfer After Pin Disruption or Relocation of Fuel or Cladding
  • 3.7.1. Fuel-pin Heat Transfer After Pin Disruption in PLUTO2 or LEVITATE
• 3.8. Heat-transfer Time Step Control
• 3.9. Steady-State and Single-Phase Transient Hydraulics
  • 3.9.1. Introduction
  • 3.9.2. Basic Equations
  • 3.9.3. Flow Orifices
  • 3.9.4. Finite Difference Equations - Coolant Flow Rates
  • 3.9.5. Coolant Pressures
• 3.10. Multiple-Pin Model
  • 3.10.1. Introduction
  • 3.10.2. Physical Model
  • 3.10.3. Numerical Methods
  • 3.10.4. Detailed Mathematical Treatment
  • 3.10.5. Relationship Between Single Pin and Multiple Pin Models
• 3.11. Subassembly-to-subassembly Heat Transfer
• 3.12. Interaction with Other Models
  • 3.12.1. Reactivity Feedback
  • 3.12.2. Coupling Between Core Channels and PRIMAR-4
• 3.13. Subroutine Descriptions and Flowcharts
• 3.14. Subchannel Treatment Details
  • 3.14.1. Model Features
  • 3.14.2. Basic Equations
  • 3.14.3. Numerical Procedures
  • 3.14.4. Interfacing with Other Models in the Code
  • 3.14.5. Data Management
  • 3.14.6. Coding Overview and Subroutines
  • 3.14.7. Required Computer Capabilities
• 3.15. Input and Output
  • 3.15.1. Input Description
  • 3.15.2. Output Description
  • 3.15.3. Subchannel Information
• 3.16. Thermal Properties of Fuel and Cladding
  • 3.16.1. Fuel Density
  • 3.16.2. Fuel Thermal Conductivity
• 3.17. References
• 3.18. Nomenclature
• 3.19. Appendices
  • 3.19.1. APPENDIX 3.1: Degree of Implicitness for Flow and Temperature Calculations
  • 3.19.2. APPENDIX 3.2: Input Preprocessor
  • 3.19.3. APPENDIX 3.3: Visualization
  • 3.19.4. APPENDIX 3.4: Coolant Physical Properties