1. Thermal Hydraulic Studies for PFBR using PHOENICS
U. PARTHA SARATHY
Indira Gandhi Centre for Atomic Research
Kalpakkam
May 3-5 th 2004
Notes

2. PROTOTYPE FAST BREEDER REACTOR (PFBR)
Power MWe, 1250 MWth
Fuel – Mixture of UO2 (79 %) and PuO2 (21 %)
Coolant – Sodium (liquid metal) in Pry and Secy Circuits
– Water in Tertiary Circuit
High Temperatures
High Velocities
Problems –
High temperatures leading to creep, fatigue damage
Flow induced vibrations
Thermal striping
Gas entrainment
U. Partha Sarathy, IGCAR /05/2004

3. PFBR Primary Circuit PUMP IHX Hot Pool CORE Inner Vessel Nuclear heat
Cold Pool
Grid Plate
U. Partha Sarathy, IGCAR /05/2004

4. Schematic PFBR Flow Sheet
Primary Circuit
Secondary Circuit
Steam/Water circuit
U. Partha Sarathy, IGCAR /05/2004

5. HYDRAULIC ANALYSIS OF GRID PLATE- e Page

6. HYDRAULIC ANALYSIS OF GRID PLATE
Consists of 1758 sleeves
Receives flow from four pipes
Distributes flow to various subassemblies
Objectives
Flow and pressure distribution
Pressure drop in GP
Velocity over sleeves
U. Partha Sarathy, IGCAR /05/2004

7. HYDRAULIC ANALYSIS OF GRID PLATE
Modelling
2-D model in cylindrical co-ordinates (r- θ)
Sleeves modeled through porosity in radial and circumferential directions (Porous body formulation)
Inlet as Velocity BC
Outlets as mass sinks
Pressure drop due to sleeves modeled through Zukauskas correlation
Addition of resistance terms in the momentum equation using ‘ground’ subroutine.
K-E Turbulence model
Schematic of Grid Plate
U. Partha Sarathy, IGCAR /05/2004

8. Results of Grid Plate Analysis
Predicted ΔP is 4.6 m of sodium
Similar to that extrapolated from 1:3 scale air experiments.
Pressure contours are concentric – uniform flow through fuel SA
Maximum cross flow velocity is 8.5 m/s
Flow Distribution in Grid Plate
U. Partha Sarathy, IGCAR /05/2004

9. Thermal Analysis of Hot and Cold Pools- Title Page

10. Thermal Analysis of Hot and Cold Pools
Objectives
Inner Vessel temperature distribution
Stratification In sodium pools
Hot pool free surface velocity & temperature
CORE
U. Partha Sarathy, IGCAR /05/2004

11. CFD Model and Boundary Conditions
Modelling
2-D model in cylindrical co-ordinates (r-z)
Core is modeled as a block
Porous body approximation for immersed components – IHX, Pump
Mass sink at IHX & PUMP inlets
Velocity BC at IHX and Core outlets
Conjugate thermal hydraulic analysis of hot & cold pools including IV
K-E Turbulence model
U. Partha Sarathy, IGCAR /05/2004

12. Flow Distribution in Hot and Cold Pools
Good mixing in hot and cold pools
U. Partha Sarathy, IGCAR /05/2004

13. ΔT across thickness is 64 K
Temperature Distribution in Inner Vessel
Results
Tmax in IV is 534 OC
ΔT across thickness is 64 K
Max hot pool free surface temperature is 572 OC
Hot Pool Free Surface Temperature Distribution
U. Partha Sarathy, IGCAR /05/2004

14. Flow Distribution in SG Inlet Plenum- Title Page
STEAM GENERATOR INLET PLENUM

15. 3/5 scale model of SG Inlet Plenum
Schematic of PFBR SG
3/5 scale model of SG Inlet Plenum
Objective:To identify flow distribution devices and reduce maximum radial velocity over tubes from FIV considerations.
U. Partha Sarathy, IGCAR /05/2004

16. 3/5 scale model of SG Inlet Plenum
Modelling
3/5 scale model
3-D cylindrical coordinates
180 O symmetric model
K-E turbulence model
Inlet as velocity BC
3/5 scale model of SG Inlet Plenum
U. Partha Sarathy, IGCAR /05/2004

17. Flow distribution in Inlet window region at 1430 mm from inlet
=0
Flow distribution in SG Inlet Plenum – Basic Configuration
1430 mm
Radial Velocity Profile along the Window with Basic Configuration
U. Partha Sarathy, IGCAR /05/2004

18. Axial Velocity in the Annulus at 575 mm – Basic Configuration
U. Partha Sarathy, IGCAR /05/2004

19. 3/5 scale model of SG Inlet plenum with Flow distribution devices
Porous plate used as a Flow distribution devices
Porous plate
Porous body formulation for porous plate and porous shell
U. Partha Sarathy, IGCAR /05/2004

20. Axial Velocity in the Annulus at 575 mm from Inlet with Different Porous Plates
U. Partha Sarathy, IGCAR /05/2004

21. U. Partha Sarathy, IGCAR 05/05/2004

22. Flow distribution in Inlet window region at 1430 mm from inlet
3/5 scale model of SG Inlet plenum with Flow distribution devices
1430 mm
(= 0)
Flow distribution in Inlet window region at 1430 mm from inlet
Flow distribution in SG Inlet plenum with Flow distribution devices
U. Partha Sarathy, IGCAR /05/2004

23. U. Partha Sarathy, IGCAR 05/05/2004

24. RESULTS
Combination of graded porous plate and porous shell render as uniform flow both axially and circumferentially.
The distributions of porosity in the plate and shell have been identified.
Maximum radial velocity is 0.75 m/s (average is 0.45 m/s) whereas the same is 3 m/s in basic configuration
U. Partha Sarathy, IGCAR /05/2004

25. Inter-Wrapper flow Studies-Title Page

26. Inter-Wrapper flow Studies - Steady State
Objectives
Effect of IWF on SA clad hotspot
Flow distribution in IWS
To develop a model for studying various design basis events which will give detailed temperature distribution in hot and cold pools
Inter Wrapper flow
Sub-Assembly Steel hexagonal Wrapper
U. Partha Sarathy, IGCAR /05/2004

27. Sodium Flow in Primary Circuit
DHX
CORE
U. Partha Sarathy, IGCAR /05/2004

28. CFD model for IWS and Hot and Cold Pools
Modeling
2-D cylindrical coordinates (r-z)
Inlets as velocity BC
Outlets as mass sink
Porous body formulation for core and other immersed structures
Coupling with 1-D model for neutronics, heat transfer calculations in core, IHX, DHX etc.
CFD model for IWS and Hot and Cold Pools
U. Partha Sarathy, IGCAR /05/2004

29. Schematic of the SA Computational
Model
Schematic of Fuel SA
U. Partha Sarathy, IGCAR /05/2004

30. Exchange of Results between 1-D and 2-D PHOENICS Models for Boundary Conditions
U. Partha Sarathy, IGCAR /05/2004

31. Flow Chart for Coupled 1D Code – PHOENICS code Calculations
U. Partha Sarathy, IGCAR /05/2004

32. Flow Distribution in Hot
m/s
m/s
Flow Distribution in Hot
and Cold pools
Temperature Contours in Hot and Cold pools
U. Partha Sarathy, IGCAR /05/2004

33. Temperature and Velocity Distribution in Inter- Wrapper Space
425
415
555
405
395 OC
m/s
m/s
Temperature and Velocity Distribution in Inter- Wrapper Space
U. Partha Sarathy, IGCAR /05/2004

34. Temperature Distribution in IV
Results
SSA outlet temperature increases by about 2 K
Total heat transferred to IWS is 370 kW
Axial temperature gradient of hot/cold interface is 150 K/m
Temperature Distribution in IV
Temperature Distribution in MV
U. Partha Sarathy, IGCAR /05/2004

35. Inter-Wrapper flow Studies - Transient Analysis (under progress)
Station blackout incident
All pumps trip
Primary circuit flow coasts down
Secondary circuits not available
Reactor trips only at 2.5 s
Temperature inside SA goes up
Good amount of heat is taken away by the IWF
U. Partha Sarathy, IGCAR /05/2004

36. Transient Evolution of Temperatures in Hot and Cold Pools
Results
Transient Evolution of Temperatures in Hot and Cold Pools

37. Thank You