FRAPCON/FRAPTRAN Users Group Meeting:

Recent Code Updates and Future Plans

Ken GeelhoodWalter Luscher

Carl BeyerPacific Northwest National Laboratory

September 19, 2013

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Outline

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Current code versionsChanges made so far

FRAPCON-3.5FRAPTRAN 1.5FRAPCON-ARM

Recent code benchmarksUpcoming Changes

FRAPCON-3.5FRAPTRAN 1.5

Changes beyond these versionsNext Code Release

Current Code Versions

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FRAPCON-3.4aCode Description: NUREG/CR-7022 Vol.1Integral Assessment: NUREG/CR-7022 Vol.2

FRAPTRAN 1.4Code Description: NUREG/CR-7023 Vol.1Integral Assessment: NUREG/CR-7023 Vol.2

Consistent material properties in both codesMaterial Property Correlations: NUREG/CR-7024

Documentation available on: http://frapcon.labworks.org/

The ongoing development of FRAPCON-3 and FRAPTRAN is sponsored by the U.S. NRC

Changes Made to Date:FRAPCON-3.5

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Model improvementsModel for gaseous swelling added to better predict cladding hoop strain during high burnup ramp testsImproved primary creep modelImproved beginning of life temperature predictions

New CapabilitiesAbility to model pellets with chamfers was addedAbility to input variable axial node lengths was addedMore output was added for stochastic analysisAxial variation of enrichment, gadolinia, and central holeMore time steps, nodes, and axial shapes allowedGadolinia assumption evaluated

New model for swellingUser guidance developed

Changes Made to Date:FRAPCON-3.5

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Error correctionBetter error messages were added to help debug input fileDefault values in manual and code were matched

FRAPCON-3.5 model Improvements:Gaseous Swelling

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Gaseous swelling observed between 960˚C and 1832˚C

Model is linearly phased in between 40 and 50 GWd/MTU and fully applied above 50 GWd/MTU

0.0

1.0

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0 500 1000 1500 2000 2500

Swel

ling,

DV/

V (%

)

Temperature (°C)

Mogensen Data at 39 GWd/MTU Mogensen Data at 33 GWd/MTU Gaseous Swelling Model

FRAPCON-3.5 model Improvements:Gaseous Swelling

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New model improves predictions of ramp hoop strain at high burnup

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-1.5

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1.5

15 25 35 45 55 65 75 85

Pred

icte

d m

inus

Mea

sure

d Pl

astic

Str

ain

Incr

amen

t, %

Rod Average Burnup, GWd/MTU

Original Assessment Cases Original Assessment ModSCIP Long Hold Times SCIP Long ModSCIP Short Hold Times SCIP Short ModB&W Stud Long Hold Time B&W Mod

FRAPCON-3.5 model Improvements:Improved Primary Creep

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New model improves prediction of primary creep following stress reversals and stress changes

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-1.E-03

-5.E-04

0.E+00

5.E-04

1.E-03

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2.E-03

3.E-03

3.E-03

0 1000 2000 3000 4000 5000 6000

Cree

p st

rain

, m/m

Time, hours

Data New Methodology Old Methodology

+30MPa +110MPa-50MPa-75MPa

FRAPCON-3.5 model Improvements:Axial Variations

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User may input custom axial node lengthsFor each axial node, the user may input a different value of

EnrichmentGadolinia concentrationPresence or absence of central holeSize of central hole

Old input of equal length axial nodes and constant values for all nodes still work

Changes Made to Date:FRAPTRAN 1.5

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Model improvementsChanges made to how the code does ballooning calculationsDouble sided oxidation changed

New CapabilitiesNumber of input coolant zones changed from 10 to 20Interpolate between input coolant zones for axial nodesAbility to specify an external plenum volumeMaximum number of axial nodes changed from 25 to 150Different values of gadolinia for each nodeAbility to model chamfers

Changes Made to Date:FRAPTRAN 1.5

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Error correctionLower bound for Cathcart/Pawel model changed from 1000K to 1073KErrors in heat transfer correlations correctedBetter error messages were added to help debug input fileDefault values in manual and code were matchedError in fill gas composition after rupture

Review of FLECHT reflood correlation performed

FRAPTRAN 1.5 model Improvements:Ballooning Model

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More strain values are output to FRAPTRAN

Thinned cladding used to calculation ECRIncreased diameter used to calculation metal water reaction energy

FRAPTRAN 1.5 model Improvements:ID Oxidation

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New options addedFRAPTRAN 1.4

ID oxidation only calculated in burst area after burstFRAPTRAN 1.5

Option to calculate ID oxidation one of two waysFRAPTRAN 1.4 method

-or-Calculate for all nodes regardless of burst if nodal burnup exceeds value set by user

Changes made to Date:Uncertainty Analysis with FRAPCON-ARM

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Stochastic framework capable of running many realizations of FRAPCON-3.4 varying:

Manufacturing uncertaintiesModel uncertaintiesPower uncertainties

Package reads data from each realization and compiles distributions for each output of interest. Allows staff to validate vendor predictions of nominal and upper tolerance limit for various code outputs.Methodology does not rely on assumptions of normality for input or output distributions as the RMS methods typically used in industry do.

Uncertainty Analysis with FRAPCON-ARMInput

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Uncertainty Analysis with FRAPCON-ARMInput

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Uncertainty Analysis with FRAPCON-ARMOutput

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Calculated Upper Tolerance Limits

Output distributions Inputs and outputs for each realization

Uncertainty Analysis with FRAPCON-ARMOutput

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Output vs. InputTest for Normality

Recent Code Benchmarks

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IFA-699 Subject: CreepPresented at: 2011 EHPG Meeting and 2013 TopFuel

SCIP, TRANS RAMP IVSubject: FGR during short hold time rampsPresented at: Not publically presented

Hydrogen pickup modelsPresented at: 2011 Water Reactor Fuel Performance Meeting

IRSN RIA BenchmarksHigh burnup RIA tests

FUMEX-IIIParticipated with TRACTEBEL and NRI

Upcoming Changes:FRAPCON-3.5

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New CapabilitiesImproved ability to model refabricated rodlets

Model base irradiation and create restart fileModel test on refabricated rod using selected axial nodes from restart

Excel input generator updates and improvements to match FRAPCON-3.5 change

Possible support of SNAP within 1-2 years

Upcoming Changes:FRAPTRAN 1.5

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Excel input generator updates and improvements to match FRAPTRAN 1.5 changes

Possible support of SNAP within 1-2 years

Changes beyond FRAPCON-3.5 and FRAPTRAN 1.5

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FORTRAN UpdatesUse all Modern F95Reduce need for compiler optionsImprove variable declaration and use dynamic dimensioning

Improvement in reliabilityReduce crashesRetune FRAPFGR modelFix FRAPTRAN problems with coolant boundary conditions

Address peer review itemsCouple FRAPCON and DATING for spent fuel creep analysisDevelop stochastic capability for FRAPTRANInclude new ANS5.4 model in FRAPCONUpdate decay heat model

New Code Release

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Plans to release FRAPCON-3.5 and FRAPTRAN 1.5 early 2014Documentation

NUREG/CR