Embed Size (px)
Citation preview
Spent Fuel and Waste Science and Technology
HBU Demo Cask Thermal ModelingCOBRA-SFS and STAR-CCM+PNNL-SA-134323
David Richmond, James FortPacific Northwest National Laboratory
SFWST Working Group MeetingMay 23, 2018
Spent Fuel and Waste Science andTechnology
April 30, 2018 EPRI ESCP 2
Outline
STAR-CCM+ Modeling COBRA-SFS Modeling Code Comparisons Blind Data Comparisons
– Internal convection modeling Sensitivity Studies
– Gaps Conclusions Future Work
Spent Fuel and Waste Science andTechnology
What is STAR-CCM+?
Commercial CFD (Computational Fluid Dynamics) software package Provides flexible multiphysics modeling of transport phenomena
– Fluid dynamics– Heat transfer– Mass transfer
Readily treats complex geometries through automated meshing
April 30, 2018 EPRI ESCP 3
Spent Fuel and Waste Science andTechnology
TN-32B Model
Fine mesh, 25M cells Med mesh, 6.8M cells (shown) Fuel rods approximated
– Porous media– Effective properties
April 30, 2018 ERPI ESCP 4
Spent Fuel and Waste Science andTechnology
What is COBRA-SFS?
Heavily Modified COBRA-TF Fluid Flow
– Subchannel Analysis Solid Energy
– Finite Difference Method Radiation
– Surface to surface
April 30, 2018 EPRI ESCP 5
Spent Fuel and Waste Science andTechnology
TN-32B Model (not to scale)
786 Solid Nodes 32 rodded assemblies
– 324 subchannels in Fuel 289 pin positions per assembly 32 open channels 80 Axial Levels 1,634,720 cells
April 30, 2018 EPRI ESCP 6
Spent Fuel and Waste Science andTechnology
Code Comparisons
COBRA-SFS STAR-CCM+
Category
Rod Arrays Detailed SimplifiedFlow in Open Spaces Simplified DetailedValidation Extensive LimitedCPU time Fast Slow
April 30, 2018 EPRI ESCP 7
Spent Fuel and Waste Science andTechnology
BLIND DATA COMPARISONS
8
Spent Fuel and Waste Science andTechnology
Average difference (data – prediction ˚C)
April 30, 2018 EPRI ESCP 9
Code 2 (3K7) 6 (30A) 14 (57A) 19 (3U9) 24 (3U4) 28 (3U6) 31 (5T9)
STAR-CCM+ 13.2 18.8 22.3 23.5 15.7 24.0 12.3
COBRA-SFS 18.2 20.3 14.0 17.5 19.1 30.9 16.2
Spent Fuel and Waste Science andTechnology
Assembly 14 (57A) Blind Predictions
April 30, 2018 10
0
20
40
60
80
100
120
140
160
125.0 150.0 175.0 200.0 225.0 250.0 275.0
Elev
atio
n (in
.)
Temperature (˚C)
Data COBRA-SFS STAR-CCM+
Spent Fuel and Waste Science andTechnology
Assembly 2 (3K7) Blind Predictions
April 30, 2018 11
0
20
40
60
80
100
120
140
160
100.0 125.0 150.0 175.0 200.0 225.0 250.0
Elev
atio
n (in
.)
Temperature (˚C)
Data COBRA-SFS STAR-CCM+
Spent Fuel and Waste Science andTechnology
Assembly 28 (3U6) Blind Predictions
April 30, 2018 12
0
20
40
60
80
100
120
140
160
100.0 125.0 150.0 175.0 200.0 225.0 250.0
Elev
atio
n (in
.)
Temperature (˚C)
Data COBRA-SFS STAR-CCM+
Spent Fuel and Waste Science andTechnology
STAR-CCM+ shows complex recirculation
April 30, 2018 13
Spent Fuel and Waste Science andTechnology
April 30, 2018 14
downflow
upflow
Spent Fuel and Waste Science andTechnology
SENSITIVITY STUDIES
15
Spent Fuel and Waste Science andTechnology
TN-32B Sensitivities
April 30, 2018 16
Condition PCT Difference from Baseline (˚C)
Increase Basket Emissivity to 0.8 -2Closed rail-shell gaps -299% Decay Heat -298% Decay Heat -395% Decay Heat -890% Decay Heat -16Basket-Rail Gap 0.15 in. -5Basket-Rail Gap 0.10 in. -12Basket-Rail Gap 0.05 in. -20
Spent Fuel and Waste Science andTechnology
Cask specs are variable
April 30, 2018 17
Spent Fuel and Waste Science andTechnology
Assembly 14 (57A) Basket-Rail Gaps
April 30, 2018 18
0
20
40
60
80
100
120
140
160
100.0 125.0 150.0 175.0 200.0 225.0 250.0
Elev
atio
n (in
.)
Temperature (˚C)
Data Baseline SAR gap
0.1 Gap 0.05 Gap
Spent Fuel and Waste Science andTechnology
Assembly 2 (3K7) Basket-Rail Gaps
April 30, 2018 19
0
20
40
60
80
100
120
140
160
100.0 125.0 150.0 175.0 200.0 225.0 250.0
Elev
atio
n (in
.)
Temperature (˚C)
Data Baseline SAR gap
0.1 Gap 0.05 Gap
Spent Fuel and Waste Science andTechnology
Assembly 28 (3U6) Basket-Rail Gaps
April 30, 2018 20
0
20
40
60
80
100
120
140
160
100.0 125.0 150.0 175.0 200.0 225.0 250.0
Elev
atio
n (in
.)
Temperature (˚C)
Data Baseline SAR gap
0.1 Gap 0.05 Gap
Spent Fuel and Waste Science andTechnology
Adjusted Best Estimate PCT
Date Presentation or Meeting Title 21
205 214 211 201
201 224 235 235 223 202
208 235 224 238 235 213
213 235 235 227 235 213
206 222 236 235 224 206
206 215 213 202
Spent Fuel and Waste Science andTechnology
Adjusted Best Estimate Cladding Surface
Date Presentation or Meeting Title 22
Spent Fuel and Waste Science andTechnology
Conclusions
Accurate prediction of thermal expansion and gap size is needed to accurately predict temperatures, especially in a conduction dominated cask
Internal convection is not a dominant force in this cask but can influence outer basket assemblies
CFD simulations may be needed to reliably predict complex recirculation
April 30, 2018 EPRI ESCP 23
Spent Fuel and Waste Science andTechnology
FUTURE WORK
24
Spent Fuel and Waste Science andTechnology
Detailed Loading data will give realistic initial conditions
Date Presentation or Meeting Title 25
200
225
250
275
300
325
350
375
400
425
450
475
0 5 10 15 20 25 30 35 40
PCT
(F)
Hours
PCT vs. Time
50F Drying
50F Backfill at 12 Hours
Spent Fuel and Waste Science andTechnology
Date Presentation or Meeting Title 26
100
125
150
175
200
225
250
275
300
325
350
375
400
425
450
475
11/15/17 0
11/16/17 0
11/17/17 0
11/18/17 0
11/19/17 0
11/20/17 0
11/21/17 0
Tem
pera
ture
(˚F)
Cell 14 Thermocouple 6
Spent Fuel and Waste Science andTechnology
Pad data will verify ambient correlations and assumptions
Date Presentation or Meeting Title 27
60
65
70
75
80
85
90
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Air T
empt
erat
ure
(˚F)
Hours
North Anna Air Temperature
Spent Fuel and Waste Science andTechnology
Acknowledgements
April 30, 2018 28
