1. FRAPCON/FRAPTRAN Users Group Meeting: Recent Code Updates and Future Plans Ken Geelhood Walter Luscher Carl Beyer Pacific Northwest National Laboratory September 19, 2013 1

2. Outline 2 Current code versions Changes made so far FRAPCON-3.5 FRAPTRAN 1.5 FRAPCON-ARM Recent code benchmarks Upcoming Changes FRAPCON-3.5 FRAPTRAN 1.5 Changes beyond these versions Next Code Release

3. Current Code Versions 3 FRAPCON-3.4a Code Description: NUREG/CR-7022 Vol.1 Integral Assessment: NUREG/CR-7022 Vol.2 FRAPTRAN 1.4 Code Description: NUREG/CR-7023 Vol.1 Integral Assessment: NUREG/CR-7023 Vol.2 Consistent material properties in both codes Material Property Correlations: NUREG/CR-7024 Documentation available on: http://frapcon.labworks.org/http://frapcon.labworks.org/ The ongoing development of FRAPCON-3 and FRAPTRAN is sponsored by the U.S. NRC

4. Changes Made to Date: FRAPCON-3.5 4 Model improvements Model for gaseous swelling added to better predict cladding hoop strain during high burnup ramp tests Improved primary creep model Improved beginning of life temperature predictions New Capabilities Ability to model pellets with chamfers was added Ability to input variable axial node lengths was added More output was added for stochastic analysis Axial variation of enrichment, gadolinia, and central hole More time steps, nodes, and axial shapes allowed Gadolinia assumption evaluated New model for swelling User guidance developed

5. Changes Made to Date: FRAPCON-3.5 5 Error correction Better error messages were added to help debug input file Default values in manual and code were matched

6. FRAPCON-3.5 model Improvements: Gaseous Swelling 6 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

7. FRAPCON-3.5 model Improvements: Gaseous Swelling 7 New model improves predictions of ramp hoop strain at high burnup

8. FRAPCON-3.5 model Improvements: Improved Primary Creep 8 New model improves prediction of primary creep following stress reversals and stress changes

9. FRAPCON-3.5 model Improvements: Axial Variations 9 User may input custom axial node lengths For each axial node, the user may input a different value of Enrichment Gadolinia concentration Presence or absence of central hole Size of central hole Old input of equal length axial nodes and constant values for all nodes still work

10. Changes Made to Date: FRAPTRAN 1.5 10 Model improvements Changes made to how the code does ballooning calculations Double sided oxidation changed New Capabilities Number of input coolant zones changed from 10 to 20 Interpolate between input coolant zones for axial nodes Ability to specify an external plenum volume Maximum number of axial nodes changed from 25 to 150 Different values of gadolinia for each node Ability to model chamfers

11. Changes Made to Date: FRAPTRAN 1.5 11 Error correction Lower bound for Cathcart/Pawel model changed from 1000K to 1073K Errors in heat transfer correlations corrected Better error messages were added to help debug input file Default values in manual and code were matched Error in fill gas composition after rupture Review of FLECHT reflood correlation performed

12. FRAPTRAN 1.5 model Improvements: Ballooning Model 12 More strain values are output to FRAPTRAN Thinned cladding used to calculation ECR Increased diameter used to calculation metal water reaction energy

13. FRAPTRAN 1.5 model Improvements: ID Oxidation 13 New options added FRAPTRAN 1.4 ID oxidation only calculated in burst area after burst FRAPTRAN 1.5 Option to calculate ID oxidation one of two ways FRAPTRAN 1.4 method -or- Calculate for all nodes regardless of burst if nodal burnup exceeds value set by user

14. Changes made to Date: Uncertainty Analysis with FRAPCON-ARM 14 Stochastic framework capable of running many realizations of FRAPCON-3.4 varying: Manufacturing uncertainties Model uncertainties Power 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.

15. Uncertainty Analysis with FRAPCON-ARM Input 15

16. Uncertainty Analysis with FRAPCON-ARM Input 16

17. Uncertainty Analysis with FRAPCON-ARM Output 17 Calculated Upper Tolerance Limits Output distributions Inputs and outputs for each realization

18. Uncertainty Analysis with FRAPCON-ARM Output 18 Output vs. Input Test for Normality

19. Recent Code Benchmarks 19 IFA-699 Subject: Creep Presented at: 2011 EHPG Meeting and 2013 TopFuel SCIP, TRANS RAMP IV Subject: FGR during short hold time ramps Presented at: Not publically presented Hydrogen pickup models Presented at: 2011 Water Reactor Fuel Performance Meeting IRSN RIA Benchmarks High burnup RIA tests FUMEX-III Participated with TRACTEBEL and NRI

20. Upcoming Changes: FRAPCON-3.5 20 New Capabilities Improved ability to model refabricated rodlets Model base irradiation and create restart file Model 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

21. Upcoming Changes: FRAPTRAN 1.5 21 Excel input generator updates and improvements to match FRAPTRAN 1.5 changes Possible support of SNAP within 1-2 years

22. Changes beyond FRAPCON-3.5 and FRAPTRAN 1.5 22 FORTRAN Updates Use all Modern F95 Reduce need for compiler options Improve variable declaration and use dynamic dimensioning Improvement in reliability Reduce crashes Retune FRAPFGR model Fix FRAPTRAN problems with coolant boundary conditions Address peer review items Couple FRAPCON and DATING for spent fuel creep analysis Develop stochastic capability for FRAPTRAN Include new ANS5.4 model in FRAPCON Update decay heat model

23. New Code Release 23 Plans to release FRAPCON-3.5 and FRAPTRAN 1.5 early 2014 Documentation NUREG/CR