Cooper Spacer Void Model Benchmark - Studsvik 2017-05-19 · Cooper Spacer Void Model Benchmark 2006 CMS User Group Meeting Minneapolis, Minnesota 3 History of Cooper SIM-3 Reload

in support of

Cooper Spacer Void Model Benchmark

2006 CMS User Group MeetingMinneapolis, Minnesota

May 16-17, 2006

Presented By: Kurt A. [email protected]

Cooper Spacer Void Model Benchmark2006 CMS User Group Meeting

Minneapolis, Minnesota2

Presentation Outline

OutlineHistory of Cooper SIMULATE-3 Reload ModelPast Reload Model PerformanceOverview of SIMULATE-3 Spacer Void OptionEvaluation of Three Spacer Void Model Options

TIP ComparisonsThermal Limits

Sensitivity to Implementation Reload CycleObservations



History of Cooper SIM-3 Reload Model

Cooper CASMO-4/SIMULATE-3 Reload ModelGoal was to develop and license core physics methods comparable to those used at NSPImplemented for Cooper Cycle 20Built C4/S3 Models for Cooper Cycles 15-20Benchmarked Cycles 16 through early Cycle 20Major model documentation

Report documenting reload model inputs and referencesQualification and Application of Methods Topical – Never submitted to the NRC due to change in management

at NPPD



History (continued)

Revised Reload ModelIntroduction of more robust hydraulic model coincided with implementation of the GARDEL core monitor at CooperNew benchmark covering Cooper Cycles 20-22Updated model documentation

Updated reload model report for Cycles 20B-23 and new hydraulic modelPrepared new CASMO-4 fuel bundle model reportPrepared new model benchmark report for Cycles 20-22



Evolution of the Cooper Hydraulic Model

OriginalTotal bypass flow modeled as a function of core power and core flow based on vendor data

Same methodology used for Monticello

RevisedSwitched to most robust SIM-3 hydraulic model in conjunction with the implementation of GARDEL

ProposedActivate spacer void effect option (BWR.SPV)

In attempt to address poor Cycle 23 TIP comparisons



Hydraulic Model Summary

Explicit leakage paths to bypass

Bypass flow fraction = f(P,F)

ONONONBypass Void Effect Option

ONOFFOFFSpacer Void Effect Option

Explicit water tube flow rates

Explicit bundle leakage calc

BYPBYPONFlow Balance Option

ONONONHeat Balance Option

ProposedRevisedOriginal



Past Reload Model Performance

Cycles 16-20Original SIM-3 hydraulic modelGE9B fuel with GE14 introduced in Cycle 20

Cycles 20-22Revised SIM-3 hydraulic modelTransition from GE9B to GE14 cores

Cycle 23Revised SIM-3 hydraulic modelFirst reload with all GE14 fuel bundles



Past Performance (continued)

0.0590.0360.052Nodal Power (exc. end nodes)

TIP Comparisons (rms)

-0.003 / 0.0110.024 / 0.052n/aMFLPD (vs. vendor methods)

0.0230.0200.026Radial Power (integrated)

0.0430.0260.034Axial Power (planar)

0.045 / 0.0220.047 / 0.027n/aMFLCPR (vs. vendor methods)

-0.011 / 0.0120.034 / 0.030n/a MAPRAT (vs. vendor methods)

Thermal Limits (Bias / σ)

C23C20-22C16-20



Past Performance (continued)

Hot Core Reactivity

Cold Core Reactivity

Ramp-FlatRamp-FlatFlatTarget k shape

0.00150.00130.0025Standard deviation about target

n/a0.99210.9960Mean of all data (no best fit)

Cup / HandleCup / HandleFlatTarget k shape

n/a1.00261.0049Mean of all data (no best fit)

0.00050.00070.0022Standard deviation about target

C23C20-22C16-20



Cooper Plant Summary

BWR/4 with initial criticality in 1974548 fuel bundles in a 560 bundle core

12 dummy bundles (don’t ask)

D lattice plant150 inch active fuel lengthPower density = 49.10 kw/l

Ignoring shorter (148 in) GE14B fuel bundle

Fuel vendor is GNF



Cycles 21-23 Reload Summary

16 / 6.017 / 5.017 / 5.0Max Gd2O3 pins and w/o

164128120Number of Fuel Bundles

100%70%47%GE14 Fuel in Core (%)

20.720.019.9BOC Core Ave GWd/MTU

3.95 / 3.933.98 / 3.933.79Batch Average U-235 w/o

2 (76 / 88)2 (40 / 88)1Number of Sub-batches

Fresh Fuel Loading

580547397Cycle Energy (EFPD)

C23C22C21



Spacer Void Model Investigations

Poor axial and nodal TIP comparisons in Cycle 23 initiated investigation into spacer void model option

Model settings (default vs. optimized)Sensitivity to initial cycle of implementation

Formal benchmark analysisPrior informal analysis had identified optimized spacer void model settings for Cycles 20-22

Produced equivalent TIP comparison statistics as no spacer void optionNot implemented due to sensitivity of results to settings



Spacer Void Model Effects

Spacer Void Model EffectsCauses small modifications to be applied to the SIMULATE-3 calculated nodal void fraction to account for spacer grid effectsThe spacer void effect decays away over the distance indicated for variable DZFLOWDefault settings determined through an empirical evaluation performed by Dave Ver Planck at StudsvikBWR.SPV written to the SIMULATE-3 restart file



Spacer Void Model Settings

0.670.67n/aMultiplier on nodal qualityPROFIL

0.050.10n/aMultiplier on the magnitude of the void fraction adjustmentVOIFAC

24.024.0n/aDistance above each spacer for which spacer void effect is appliedDZFLOW

0.600.50n/aVoid fraction above which VOIFAC is appliedVOIDPT

‘BWR.SPV’, ‘opt’, SPAVOI, DZFLOW, VOIFAC, VOIDPT, PROFIL

OptimizedDefaultCurrentDescriptionVar

0.120.12n/aMultiplier on the loss coefficient, ΔP at each spacer location to determine the initial change in spacer void

SPAVOI

ONONOFFSpacer void correction model‘opt’



Nodal TIP Comparison – Cycle 21Evaluated 3 spacer void options

Original no spacer void ( )Default spacer void settings (▲)Optimized spacer void settings ( )

Spacer void activated in Cycle 21Cycle 20 had a mid-cycle outage due to fuel failure shortly after startupCycles 20A and 20B have spacer void option turned off

TIP comparisons for last 3 cyclesNodal (nodes 3-22)Radial (integrated)Axial (planar)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 2000 4000 6000 8000 10000 12000 14000

Cycle 21 Exposure (MWd/MTU)

Erro

r (%

rms)



Nodal TIP Comparison – Cycle 22Original no spacer void ( )

Far superior in first half of C21-C22Comparable to other options in second half of C21-C22Clearly best nodal comparison for C21-C22

Default spacer void option (▲) Very poor nodal TIP comparisons in first half of C21-C22

Optimized spacer void option ( )Acceptable nodal TIP comparisons in C21Poor nodal TIP comparisons in first half of C22 0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 2000 4000 6000 8000 10000 12000 14000


Erro

r (%

rms)



Nodal TIP Comparison – Cycle 23C23 first complete core of GE14 fuel bundles (w/ part length pins)Original no spacer void ( )

Very poor nodal TIP comparisons in first half of cycle

Default spacer void option (▲) and optimized spacer void ( )

Good nodal TIP comparisonsDefault spacer void option with C23 initial implementation (x)

Good nodal TIP comparisonsSlightly worse than default option implemented in Cycle 21Representative of GARDEL usage 0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 2000 4000 6000 8000 10000 12000 14000


Erro

r (%

rms)



Radial TIP Comparison – Cycle 23C21-23 radial TIP comparisons

Different spacer void options show relative similar behaviorC21-22 show small changes in consecutive TIPs as the cycle depletesCycle 23 show larger differences in consecutive TIPsAll three cycles have radial TIP comparisons in the range from 1.5% to 3.0% rms error

Most comparisons < 2.5% rms error for all spacer void options

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 2000 4000 6000 8000 10000 12000 14000


Erro

r (%

rms)



Axial TIP Comparison – Cycle 22C1-C23 axial TIP comparisons comparable to nodal TIP comparisonsOriginal no spacer void ( )

Far superior in first half of C21-C22Clearly best nodal comparison for C21-C22

Default spacer void option (▲) Very poor nodal TIP comparisons in first half of C21-C22

Optimized spacer void option ( )Acceptable nodal TIP comparisons in C21Poor nodal TIP comparisons in first half of C22

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 2000 4000 6000 8000 10000 12000 14000


Erro

r (%

rms)



Axial TIP Comparison – Cycle 23Original no spacer void ( )

Very poor nodal TIP comparisons in first half of cycle

Default spacer void option (▲) and optimized spacer void ( )

Good nodal TIP comparisonsDefault spacer void option with C23 initial implementation (x)

Good nodal TIP comparisonsSlightly worse than default option implemented in Cycle 21Representative of GARDEL usage

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 2000 4000 6000 8000 10000 12000 14000


Erro

r (%

rms)



Optimized Spacer Void – Nodal C21None of the previous options produced consistently good TIP comparisonsEvaluated different initial cycles for optimized spacer void model

C21 initial implementation ( )C20B initial implementation ( )C20A initial implementation (∗)

C20A implementation produced poor results in Cycle 21 in spite of good C20A and C20B results

nodal rms error in Cycle 20A = 3.4%nodal rms error in Cycle 20B = 3.4%

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 2000 4000 6000 8000 10000 12000 14000


Erro

r (%

rms)



Optimized Spacer Void – Nodal C22C20B initial implementation ( )

Nodal TIP comparisons for C21-22 comparable to results with no spacer voidGood comparisons in C20B

Nodal rms error in Cycle 20B = 3.1%

C20A initial implementation (∗)Much better comparisons in C22 relative to C21 resultsCycle 22 comparisons are generally slightly worse than comparisons for C20B initial Implementation ( )

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 2000 4000 6000 8000 10000 12000 14000


Erro

r (%

rms)



Optimized Spacer Void – Nodal C23C20B initial implementation ( )

Nodal TIP comparisons for C21-22 comparable to results with no spacer voidC23 nodal comparisons far superior to results with no spacer voidSlightly worse results than C21 initial implementation ( )

C20A initial implementation (∗)Cycle 22 comparisons are generally slightly worse than comparisons for C20B initial Implementation ( )

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 2000 4000 6000 8000 10000 12000 14000


Erro

r (%

rms)



Optimized Spacer Void – Axial C23C1-C23 axial TIP comparisons comparable to nodal TIPscomparisonsComparison of all spacer void options evaluated

Original no spacer void ( )Default spacer void starting C21 (▲)Default spacer void starting C23 (x)Optimized spacer void settings with C21 initial implementation ( )Optimized spacer void settings with C20B initial implementation ( )Optimized spacer void settings with C20A initial implementation (∗) 0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

0 2000 4000 6000 8000 10000 12000 14000


Erro

r (%

rms)



C23 Axial Power – No Spacer Void

0.5 1.0 1.5 2.0 2.5

100 %P 99 %W 0.275 GWd/mt

6.0 %rms4.8 %(-4)2.6 %radial2.5 %axial

1.00490 30305

10 10

0

10 10

99 %P 90 %W 0.906 GWd/mt

5.8 %rms4.7 %(-4)2.0 %radial2.8 %axial

1.00389 32905

14 14

4

14 14

98 %P 93 %W 1.872 GWd/mt

6.1 %rms5.0 %(-4)2.0 %radial3.2 %axial

1.00304 51105

8 8

0

8 8

100 %P 94 %W 2.771 GWd/mt

7.4 %rms6.9 %(-4)2.7 %radial5.1 %axial

1.00183 61705

18

12 12

18 6 18

12 12

18

100 %P 91 %W 2.883 GWd/mt

6.2 %rms5.2 %(-4)2.4 %radial3.7 %axial

1.00183 62205

0 0

0

0 0

100 %P 85 %W 3.895 GWd/mt

6.5 %rms5.6 %(-4)1.8 %radial4.4 %axial

1.00135 80305

0 0

0

0 0

100 %P 99 %W 4.985 GWd/mt

8.4 %rms8.0 %(-4)2.3 %radial6.5 %axial

1.00132 91705

16 16

16 4 16

4 4

16 4 16

16 16

100 %P 94 %W 5.679 GWd/mt

8.2 %rms7.8 %(-4)2.1 %radial6.5 %axial

1.00126 102005

16 16

16 4 16

4 4

16 4 16

16 16

100 %P 88 %W 6.644 GWd/mt

8.1 %rms7.6 %(-4)3.1 %radial5.9 %axial

1.00201 112905

16 16

16 0 16

0 0

16 0 16

16 16

Average Axial TIP Trace Nodal Comparison

CNS CYCLE 23 TIP TRACES



C23 Axial Power – No Spacer Void

0.5 1.0 1.5 2.0 2.5

100 %P 92 %W 7.645 GWd/mt

6.3 %rms5.5 %(-4)2.8 %radial3.8 %axial

1.00243 11006

12 12

12 0 12

0 0

12 0 12

12 12

99 %P 94 %W 8.644 GWd/mt

5.6 %rms4.8 %(-4)2.3 %radial3.4 %axial

1.00254 22106

12 12

12 0 12

0 6 0

12 0 12

12 12





C23 Axial Power – Default (C21)

0.5 1.0 1.5 2.0 2.5

100 %P 99 %W 0.275 GWd/mt

5.5 %rms4.1 %(-4)2.3 %radial2.7 %axial

1.00316 30305

10 10

0

10 10

99 %P 90 %W 0.906 GWd/mt

5.2 %rms3.7 %(-4)1.7 %radial2.6 %axial

1.00223 32905

14 14

4

14 14

98 %P 93 %W 1.872 GWd/mt

5.3 %rms3.9 %(-4)2.2 %radial2.4 %axial

1.00131 51105

8 8

0

8 8

100 %P 94 %W 2.771 GWd/mt

5.6 %rms4.8 %(-4)2.6 %radial3.0 %axial

1.00012 61705

18

12 12

18 6 18

12 12

18

100 %P 91 %W 2.883 GWd/mt

5.3 %rms3.9 %(-4)2.4 %radial2.8 %axial

0.99993 62205

0 0

0

0 0

100 %P 85 %W 3.895 GWd/mt

5.4 %rms3.9 %(-4)1.8 %radial3.2 %axial

0.99928 80305

0 0

0

0 0

100 %P 99 %W 4.985 GWd/mt

5.9 %rms5.0 %(-4)2.4 %radial3.5 %axial

0.99903 91705

16 16

16 4 16

4 4

16 4 16

16 16

100 %P 94 %W 5.679 GWd/mt

5.6 %rms4.7 %(-4)2.2 %radial3.6 %axial

0.99867 102005

16 16

16 4 16

4 4

16 4 16

16 16

100 %P 88 %W 6.644 GWd/mt

6.1 %rms5.1 %(-4)3.1 %radial3.5 %axial

0.99896 112905

16 16

16 0 16

0 0

16 0 16

16 16





C23 Axial Power – Default (C21)

0.5 1.0 1.5 2.0 2.5

100 %P 92 %W 7.645 GWd/mt

5.8 %rms4.7 %(-4)2.6 %radial3.6 %axial

0.99907 11006

12 12

12 0 12

0 0

12 0 12

12 12

99 %P 94 %W 8.644 GWd/mt

5.7 %rms4.7 %(-4)2.3 %radial3.6 %axial

0.99926 22106

12 12

12 0 12

0 6 0

12 0 12

12 12





C23 Axial Power – Optimized (C20B)

0.5 1.0 1.5 2.0 2.5

100 %P 99 %W 0.275 GWd/mt

5.4 %rms4.0 %(-4)2.4 %radial2.1 %axial

1.00406 30305

10 10

0

10 10

99 %P 90 %W 0.906 GWd/mt

5.1 %rms3.8 %(-4)1.8 %radial2.2 %axial

1.00318 32905

14 14

4

14 14

98 %P 93 %W 1.872 GWd/mt

5.4 %rms4.1 %(-4)2.1 %radial2.3 %axial

1.00230 51105

8 8

0

8 8

100 %P 94 %W 2.771 GWd/mt

6.2 %rms5.5 %(-4)2.6 %radial3.8 %axial

1.00106 61705

18

12 12

18 6 18

12 12

18

100 %P 91 %W 2.883 GWd/mt

5.3 %rms4.1 %(-4)2.3 %radial2.7 %axial

1.00100 62205

0 0

0

0 0

100 %P 85 %W 3.895 GWd/mt

5.4 %rms4.2 %(-4)1.7 %radial3.1 %axial

1.00050 80305

0 0

0

0 0

100 %P 99 %W 4.985 GWd/mt

6.6 %rms6.0 %(-4)2.3 %radial4.5 %axial

1.00020 91705

16 16

16 4 16

4 4

16 4 16

16 16

100 %P 94 %W 5.679 GWd/mt

6.2 %rms5.6 %(-4)2.1 %radial4.4 %axial

1.00005 102005

16 16

16 4 16

4 4

16 4 16

16 16

100 %P 88 %W 6.644 GWd/mt

6.3 %rms5.5 %(-4)3.0 %radial3.8 %axial

1.00063 112905

16 16

16 0 16

0 0

16 0 16

16 16





C23 Axial Power – Optimized (C20B)

0.5 1.0 1.5 2.0 2.5

100 %P 92 %W 7.645 GWd/mt

5.3 %rms4.2 %(-4)2.6 %radial2.7 %axial

1.00084 11006

12 12

12 0 12

0 0

12 0 12

12 12

99 %P 94 %W 8.644 GWd/mt

5.1 %rms4.1 %(-4)2.2 %radial2.8 %axial

1.00097 22106

12 12

12 0 12

0 6 0

12 0 12

12 12





Thermal Limits Primer for PWR Types

Maximum Fraction of MCPR Operating Limit (MFLCPR)Minimum critical power ratio (MCPR) is the ratio of the bundle power required for the onset of transition boiling (critical power) to the operating bundle power. A lower MCPR is more limiting.

Tech Spec limit is 1.0. Cooper typically operates in 0.85-0.95 range.

Maximum Fraction of Limiting Power Density (MFLPD)Maximum ratio of the peak LHGR (kW/ft) in a fuel bundle to the maximum allowable LHGR determined by thermal-mechanical fuel performance analysis. LHGR limit is a function of fuel type and exposure.

Maximum Fraction of MAPLHGR Operating Limit (MAPRAT)Maximum average planar LHGR (MAPLHGR) is the maximum allowable average LHGR (kW/ft) in any plane of a fuel bundle as determined by ECCS-LOCA analysis.



Cycle 23 Thermal Limits – MFLCPRAdd GARDEL and vendor results

GARDEL LPRM adapted thermal limit (—)Vendor core follow thermal limit ( )

Summary of C23 MFLCPR resultsLPRM adaption increased MFLCPR versus off-line calculation (— vs x).Distinct differences for three spacer void options

Implementation cycle of little importance

Vendor MFLCPR values always lowestOptimized spacer void option matches adapted results in the four most recent TIPs

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

1.10

0 2000 4000 6000 8000 10000 12000 14000


MFL

CPR



Cycle 23 Thermal Limits – MFLPDSummary of C23 MFLPD results

LPRM adaption decreased MFLPD versus off-line calculation (— vs x).Spacer void implementation cycle has some impactVendor MFLPD values near lowestOptimized spacer void option matches adapted results the best of the different spacer void options

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

1.10

0 2000 4000 6000 8000 10000 12000 14000


MFL

PD



Cycle 23 Thermal Limits – MAPRATCooper still using composite ECCS MAPLHGR limits

3% setdown penalty for UBPCTNew ECCS only limits with no penalty to be implemented soon

MAPRAT becomes a non-factor

Summary of C23 MAPRAT resultsLPRM adaption decreased MAPRAT versus off-line calculation (— vs x)Spacer void implementation cycle has some impactVendor MAPRAT values near lowestOptimized spacer void option matches adapted results quite well

0.70

0.75

0.80

0.85

0.90

0.95

1.00

1.05

1.10

0 2000 4000 6000 8000 10000 12000 14000


MA

PRA

T



Impact of Implementation CycleInvestigated as to why the optimized spacer void being implemented in C20A produces worse results versus C20B when C20B implementation improves the results versus C21Compared exposure distribution at first HFP Eq Xe TIP

Zero represents distribution for C21 initial implementationOptimized spacer void settings with C20B initial implementation ( )Optimized spacer void settings with C20A initial implementation (∗)

Exposure Differences

1

3

5

7

9

11

13

15

17

19

21

23

25

-600 -400 -200 0 200 400 600

Exposure Difference (MWD/MTU)

Axi

al N

ode

(20A-21) (20B-21)



Implementation Cycle (continued)

Reviewed Cycle 21 axial TIP comparison edits from S3POST

C21 implementation Produces an axial power distribution which over-predicts the power in the lower nodes through 8 GWd/MTU

C20A implementationProduces an axial power distribution which under-predicts the power in the lower nodes through 8 GWd/MTU– Higher core average exposure in lower nodes– Lower core average exposure in upper nodes

C20B implementationThe “Goldilocks” combination of initial exposure distribution and axial void distribution



Spacer Void Model Observations

Impact on axial power distributionOptimized settings produce an axial power shape which roughly splits the difference between the axial power shapes produced with the default settings and the spacer void model turned off

Impact on axial exposure distributionDifferences in axial power distribution accumulate over the cycle

Impacts subsequent reload cyclesSome self-correcting behavior observed in the consolidation of the TIP comparison error range after 8 GWd/MTU



Observations (continued)

Impact on thermal limitsDefault spacer void settings produced lowest MFLCPR values for Cooper

Spacer void option turned off produced the highest values

No discernible trends for MFLPD and MAPRATFor C23, options with the best TIP comparisons produced the worst agreement with thermal limit values calculated by the vendor and visa versa (worst TIPs, best thermal limits)

Impact on core reactivity behaviorDefault settings produce a steeper increase in the target k curve during the approach to EOR



Target Core Reactivity Curves

Default Spacer Void Optimized Spacer Void

0.997

0.998

0.999

1.000

1.001

1.002

1.003

1.004

1.005

0 2000 4000 6000 8000 10000 12000 14000 16000

Cycle Exposure (MWd/MTU)

k-ef

fect

ive

(kef

f)

0.997

0.998

0.999

1.000

1.001

1.002

1.003

1.004

1.005

0 2000 4000 6000 8000 10000 12000 14000 16000

Cycle Exposure (MWd/MTU)

k-ef

fect

ive

(kef

f)



Things to Ponder

Interesting observationSpacer void settings producing the smallest nodal rms error at the first HFP Eq Xe TIP comparison produces best TIP comparisons throughout cycle

Post-startup calibrationsCurrently adjust cold target k versus exposure based on BOC cold critical measurementsCurrently adjust hot target k versus exposure based on first HFP Eq Xe TIP comparisonCould iterate on spacer void settings to produce best nodal TIP comparisons at first HFP Eq Xe TIP



Upcoming Model Work at Cooper

Revisiting BWR hydraulic modelAddress greater sensitivities of S-3K to specific hydraulic model inputs

S-3K used with GARDEL as core stability monitor

Address increased overprediction in bypass flow relative to vendor calculationsAddress increased overprediction of MFLCPR relative to vendor calculations (see previous bullet)Impact of active spacer void option on benchmark to vendor and plant measurements

Documents

Cooper Spacer Void Model Benchmark - Studsvik 2017-05-19 · Cooper Spacer Void Model Benchmark 2006 CMS User Group Meeting Minneapolis, Minnesota 3 History of Cooper SIM-3 Reload