1. J. R. WOLF RELAP5-3D PROGRAM MANAGER
RELAP5-3D AT THE INL RELAP5 International Users Group Meeting and Seminar Salt Lake City, Utah July 25-28
J. R. WOLF
RELAP5-3D
PROGRAM MANAGER

2. RELAP5-3D History
Models transient fluid flow in user-defined thermal-hydraulic networks
Most widely used water-cooled nuclear reactor accident analysis code
Traces roots back to the very beginning of nuclear power plant simulations
Early codes were “node and branch”,RELAPSE1 and RELAP2
True loop analysis capability began in 1970 with RELAP3

3. RELAP Has Had a Continuous History of Development at the INL
T/H codes at INL derived from Bettis FLASH-1 code (1966)
RELAP1 through RELAP3 ( )
RELAP4 (1973 – 1981)
RELAP5 (1979 – 1995)
MOD 0 (1979)
MOD 1 (1982)
MOD 1.5 (1982)
MOD 2 (1985)
MOD (1989)
MOD 3 (1990)
MOD 3.1 (1993)
MOD 3.2 (1995)
RELAP5-3D (1995 to Present)
RELAP5-RT (1997 to Present)

4. FLASH 1966 3 volume system Fill via table Choke flow model
Secondary side as constant heat transfer coefficient
HEM field equations
Plate fuel, heat in only
Explicit numerics
Hot
Cold
Przr

5. RELAPSE-1 RELAP1 1966 Evolved from FLASH (basic leak/fill capability)
Reactor kinetics
Control systems
3 Volumes
Heat Ex to Rx In
Rx Out to Heat Ex
Pressurizer
Rx Heat added at junction of volume 1 & 2
Models for nucleate and film boiling

6. RELAP-2 Similar “look&feel” of RELAPSE New models Other
07/23/11
RELAP-2
Similar “look&feel” of RELAPSE
Same leak/fill capability
Same heat transfer
3 volume system
New models
BWR considerations
Bubble separation
Introduced steam tables
Other
2x faster than RELAPSE
Improved stability
Ported to other platforms
RELAP2 BWR Description

7. RELAP3 1970 Evolved from RELAPSE and RELAP2 20 volumes
BWR applications
Trip logic
Valves
Fill/leak pressure dependent
Fuel pins/plates; conduction model
Expanded heat transfer models

8. RELAP4 1973 Evolved from RELAP3 100 Volumes True 1-D 2-fluid, slip
N2 field for accum
Secondary Network
Momentum flux term (dP/dA) & form losses
Reflood HT, fuel gap and metal-water Rx
Implicit numerics

9. RELAP5 1979 Evolved from RELAP4 “1000” volumes 1-D and X-flow
2-fluid, nonHEM
More Trips/Controls
Interfacial Momentum
Multi-channel/fuel rod model
Much expanded models & correlations
Semi-Implicit numerics

10. RELAP5-3D 1995 Evolved from RELAP5
Multi-dimensional hydraulics and Rx kinetics
Models for Radiation HT & conduction enclosure
Fuel/cladding deformation
New fluids (Gen IV Rx)
Code coupling
BPLU numeric solver
FORTRAN 90/95

11. RELAP has a Constant History of Added Capability
As new versions of RELAP are developed, capability is greatly increased at the expense of complexity and the need for better computer resources
RELAP 1,2,3
3 Equations – mass, energy, and momentum
Designed for LBLOCA analysis
RELAP4
LBLOCA
SBLOCA

12. RELAP has a Constant History of Added Capability (cont.)
RELAP5 MOD 0,1, 1.5
5 Equations - two mass, one energy, and two momentum
LBLOCA
SBLOCA
Semi implicit numerics
Operational transients
RELAP5 MOD 2, 2.5, 3.0, 3.1, 3.2
6 Equations - two mass, two energy, and two momentum
Semi, Nearly implicit numerics
Crossflow model
CCFL Model
Metal water reactions
Level tracking model

13. RELAP5 Developers

14. RELAP5-3D ModelingCapability
Single or two-phase flow
1-, 2-, or 3- dimensional flow networks
Reactor kinetics – 1-, 2-, or 3-dimensional nodal kinetics model
Heat Transfer – conduction, convection, radiation
Components – pump, compressor, turbine, valves, phase-separators, accumulators, jet-mixers, and pressurizers
Process models – critical flow, abrupt area change, form loss, phase separation at tees
Coupling capability to other codes such as CFD through the PVM Executive
Control systems
Graphical user interface

15. Major Features of RELAP5-3D
6 equations
Semi implicit hydrodynamics
Nearly implicit hydrodynamics
Single or two-phase flow
1-, 2-, or 3- dimensional flow networks
Reactor kinetics – 1-, 2-, or 3-dimensional nodal kinetics model
Heat Transfer – conduction, convection, radiation
Cross Flow model
Ability to couple directly to other codes through PVM and the PVM Executive
Metal-water interaction model
3D hydro
3D kinetics
Additional fluids
BPLU solver
Simulator capability
ECC and ECC mixing models
Godunov 2nd order in space boron tracking model
Plant and piping components, trips, controls

16. Major Features of RELAP5-3D (cont.)
RELAP5 GUI and ability to link to other GUIs such as SNAP
GEN IV heat transfer models
Pressurizer spray model
Feedwater heater model
Radiological model transport
2-D conduction
Alternate heat conduction to fluids
Compressor model
Gas diffusion model

17. 26 TOTAL RELAP5-3D Working Fluids
Water (H2O)
1984 light water (H2ON)
Heavy Water (D2O)
Hydrogen
Lithium
Potassium
Helium
Nitrogen
Sodium
Sodium-Potassium (NaK)
Lithium-Lead
Ammonia
Glycerol
Bismuth-Lead
1995 light water (H2O95)
Carbon Dioxide
New Helium (HeN)
New Xenon (XeN)
New Helium-New Xenon (HeNXeN)
Molten Salt 1 (LiF-BeF2 (FLiBe))
Molten Salt 2 (NaBF4-NaF)
Molten Salt 3 (LiF-NaF-KF (FLiNaK))
Molten Salt 4 (NaF-ZrF4)
DowThermA
R134A
Super Critical water
Blood
Different fluids can exist in thermally-coupled loops

18. Noncondensable Gases in RELAP5-3D
Air
Argon
Helium
Hydrogen
Nitrogen
Xenon
Krypton, SF
Oxygen
CO2 CO

19. The Graphical User Interface (2. 4
The Graphical User Interface (2.4.2)Facilitates Analysis of Calculated Results
Graphical display generated from input data
Color scale displays user-selected parameter
Point & click plots
Replay capability at any speed

20. VERSIONS OF RELAP5-3D
RELAP5-3D Version (Current Released version)
RELAP5-RT Version 2.4.2
RELAP5-3D Version Beta (Available to current license holders)
RELAP5-3D Version (Release date TBD)

21. RELAP5-3D Key CHANGES SINCE VERSION 2.4.3
FORTRAN 95
Restructuring with FOR_STRUCT 
Developmental Assessment 
Improved Nodal Kinetics 
ANS 2005 Decay Heat Standard 
Improved Time Step Control
Accuracy Based Thermodynamic Properties

22. RELAP5-3D Key CHANGES SINCE VERSION 2.4.2 (Cont)
Institutionalized Card 1, Option 3 (Consistent Sound Speed Calculation between Volumes and Junctions when Noncondensables are Present) 
Added Card 1 Option 27 to set Theta Velocity in Outermost Ring of Rigid Body Rotation and R-theta Symmetric Problems to 1.0 m/s
Added Card 1 Option 29 to allow more Accurate Solution to Momentum Equations for Low Flows 
Allow Fluid Interactive Capability for the Working Fluid D2O 
Allow Input Options NEW and NEWATH to use all Working Fluids 
Added Command Line Argument ‘-stat’ for Run Statistics for Developmental Assessment
2D Heat Conduction Model without Reflood
Alternate Heat Structure – Fluid Coupling Model
Linux SuSe Platform Capability

23. RELAP5-3D Key CHANGES SINCE VERSION 2.4.3 (Cont.)
Pump Head and Torque Multiplier as a Function of Pressure and Void Fraction
CO2 Properties Improvement for Running near and through the Critical Point
Improved Compressor Model (Allow Input Negative Flows on Speed Tables, Allow Compressors to Run with Noncondensable Gases) 
Allow Efficiency Multiplier (for Type-3 Turbine) using a Control Variable and Turbine Inlet Junction Form Loss Multiplier using a Control Variable
Allow PVM Coupled Restart from Uncoupled Runs 
Modified PVM Coupling to send any RELAP5-3D Nodal Kinetics Variable instead of the Restricted List of Power, Zone, Heat Structure Average Temperature, etc.

24. RELAP5-3D Applications
Wide range of nuclear power reactor applications
Many non-nuclear and non nuclear applications
Capability to analyze any type of flow and heat transfer phenomena in a piping network

25. Applications of RELAP5-3D
Naval Reactors
LWR Safety Analysis
AP-600
Nuclear power plant training simulators
Licensing code development for INER and MHI
Advanced Test Reactor
DOE International Nuclear safety Program
Cryogenic storage and delivery systems
SP-100 nuclear system
Municipal steam delivery systems
Sodium fast reactors
Wide Range of university applications

26. Advanced Reactor Applications
Super Critical Water Reactor
Gas Fast Reactor
Molten Salt
Liquid Metal
NGNP

27. GEN IV Advanced Reactor Design Applications
NGNP high temperature gas reactor
High Temperature Test Facility
Super critical water reactor
Gas fast reactor
Molten salt
Pb-Bi

28. NGNP Advanced Reactor Applications
The foundation for a thermal-hydraulic systems analysis capability directed specifically toward the NGNP has been under development for several years at the INEEL.
While the basic physical models in RELAP5-3D have been extensively validated for light water reactors, its applicability to the NGNP design must be demonstrated.
A program encompassing validation, experiments, and further code development will accomplish this. High Temperature Test facility and MHTGR calculations
RELAP5-3D provides a system-wide analysis capability and FLUENT or STARR CCM+ provides the CFD capability.
In-vessel and ex-vessel studies

29. RELAP5-3D Coupled to STAR CCM+ and FLUENT For Detailed Analysis
Upper
Plenum
RELAP5-3D
model
Core
Balance Of
Plant
CFD model
Lower
Plenum

30. GT MHTGR Fluent Calculation

31. RELAP5-3D Licenses and IRUG
RELAP5-3D is copyrighted by BEA
Growing membership in IRUG
Multiyear commercial and university license agreements being executed
BEA continue to improved turn around time for new license requests
138 days in FY’09 compared to 32 days first quarter FY’11
state universities accepting alternative language for venue and applicable law
Information about RELAP5 and the International RELAP5 Users Group can be found at

32. Current License Structure
License Costs
Depends on type of code desired, source or executable
Level of support needed for technical assistance

33. Future RELAP Development
Advanced code development is currently underway
Starting a long term project to add uncertainty quantification to RELAP5-3D
RELAP6 (Presentation later)
RELAP7 (Presentation later)

34. Acknowledgements
Bob Martin for material on the early codes and their capability