1. User Group Meeting | 2015 | Zurich, CH
FRAPCON/FRAPTRAN Users Group Meeting: Recent Code Release and Future Plans
Photo Title Slide Design #11 with PLATINUM Background
To best incorporate the contents of this title slide into your presentation(s), be sure to use the Select All command (Ctrl+A) before choosing to Copy (Ctrl+C) the content and then Pasting (Ctrl+V) it onto the title slide location within your new or existing PowerPoint file.
Ken Geelhood
Pacific Northwest National Laboratory
Richland, WA
September 18, 2018
User Group Meeting | 2015 | Zurich, CH

2. User Group Meeting | 2015 | Zurich, CH
Summary
Current code versions
Summary of Changes
FRAPCON-4.0
Upcoming Changes
Changes beyond these versions
Next Code Release
September 18, 2018
User Group Meeting | 2015 | Zurich, CH

3. User Group Meeting | 2015 | Zurich, CH
Current Code Versions
FRAPCON-4.0
FRAPTRAN-1.5 (Does NOT work with FRAPCON-4.0)
FRAPTRAN-1.5P has been released with FRAPCON-4.0 so the restart files will be properly passed
FRAPTRAN-2.0 coming soon
September 18, 2018
User Group Meeting | 2015 | Zurich, CH

4. Summary of Changes: FRAPCON-4.0
Extensive work has been done to modernize the FORTRAN language used for FRAPCON
Commons have been eliminated and variables are stored in modules for use in other subroutines
Code changed from fixed format to free format
More modern syntax has been employed for logic tests. Eg <, <=, ==, >=, > rather than lt, le, eq, ge, gt
All subroutines have been grouped into modules according to their function
Go to statements and if, then, else constructs have been replaced with CASE statements wherever possible
Need for compiler options has been eliminated
Double precision explicitly stated on all variables
All variables explicitly declared
Variables are dynamically dimensioned to the size of the current problem
No restriction on # of axial (na) or radial (nr, ngasr) nodes, no limit to the # of timesteps (im) or axial power profiles (up to im)
Code will be distributed with makefile for compiling on LINUX and OSX
September 18, 2018
User Group Meeting | 2015 | Zurich, CH

5. Summary of Changes: FRAPCON-4.0 (cont.)
Code predictions from FRAPCON-4.0 are nearly identical to FRAPCON-3.5
Several bugs have been removed and models have been improved
Update to plenum temperature model
Update to gas properties
Several new capabilities have been added
Added the ANS-5.4 (2011) Standard Fission Product Release Model
“EM” options have been removed
Ability to model spent fuel storage using the DATING creep models added
Ability to use the ANS-5.1 decay heat model to calculate heating after shutdown added
Ability to specify axial coolant conditions (Temp, Press) was added
Various “Developer” options have been added to allow the user to change various model parameters for sensitivity study
These options have the potential to change the FRAPCON results such that the outputs are no longer validated
September 18, 2018
User Group Meeting | 2015 | Zurich, CH

6. Summary of Changes: FRAPCON-4.0 (cont.)
Updates have been made to the Excel Auto Input Generator
All input variables are available to the user through this file
Tabs with required input are shown in red
Tabs with optional input for exercising various code options are shown in blue
Standard dimensions from various assembly designs are available to pre-populate input
Generator has been made dynamic (can continue as needed for axial variations, power history, coolant conditions, etc.)
Updates have been made to the Excel Plot File
Ability to plot an axial plot at a various time steps has been added to “1D data” tab
Surface plots in “2D data” tab improved
Ability added to plot axial and radial gas information added (nplot=2) e.g. gas in grains, grain boundary gas, produced gas
Ability to switch between British/SI units
September 18, 2018
User Group Meeting | 2015 | Zurich, CH

7. Summary of Changes: FRAPCON-4.0 (cont.)
Updates have been made to the QA procedures
GitHub used for version control of source code
V&V cases established
Unit test cases. Separate driver program run subroutines to verify their performance relative to hand calculations
Verification test cases. Database of test cases is being established to test all code functionality
Validation test cases. Integral Assessment cases used to validate code predictions
Code change tracking tool implemented to assign, track, and document new code developments
FRAPVALID auto validation tool from IRSN implemented to assess the impact of new code modifications
September 18, 2018
User Group Meeting | 2015 | Zurich, CH

8. Upcoming Changes (underway)
FRAPTRAN Code Modernization
Removal of unused code
Migration to FORTRAN 95
Logic Improvements
Switch from explicit dimensions to dynamic dimensions
Move sth2xt files into the code
Improved output printing
Improved linking with T/H codes (stores data for multiple rods)
FRAPCON General Improvements and Reliability
Automate time step size reduction in creep subroutine to avoid crashes
Retune FRAPFGR model to make this model the primary FGR model and add output of grain boundary gas and high burnup rim structure.
FRAPTRAN General Improvements and Reliability
Investigate and fix problems with code crashes and eliminate unnecessary error messages
Confirm validity of transient temperature solution
September 18, 2018
User Group Meeting | 2015 | Zurich, CH

9. Upcoming Changes (underway)
Development of capability to run uncertainty analyses with FRAPCON and FRAPTRAN using DAKOTA
Investigate reflood rate predictions and heat transfer coefficients in the FLECHT model
Investigate and fix as appropriate the following potential issues in the code:
Investigate radial thermal expansion of the central hole and the coupling of FRAPCON and FRAPTRAN for annular pellets
Adjust fast neutron flux and burnup for gadolinia rods
Investigate potential inconsistencies between thermal and mechanical gaps
Investigate passage of rod internal pressure from FRAPCON to FRAPTRAN
Add fuel swelling due to fission gas swelling in FRAPTRAN
Incorporation of latest version of TUBRNP radial power model
Modernization of assessment input cases to match current code capability
Development of common FRAPCON/FRAPTRAN restart file
September 18, 2018
User Group Meeting | 2015 | Zurich, CH

10. Changes Beyond These Versions
NRC and PNNL are developing a 5 year plan for FRAPCON and FRAPTRAN. Some items for this plan include:
Better integration with SNAP
Expansion of the integral assessment case inventory including most or all Halden tests
Improvements in ballooning models in axial direction, to support eventual predictions of fuel dispersal, as well as axial stack relocation, and inclusion of grid spacers
Look into vendor developments and ensure that NRC codes are following the trends, such as pellet additives, new cladding types
Ensure that the NRC codes are providing reasonable predictions for SMR fuel designs and make necessary changes
Perform a targeted literature review to keep track of domestic and international developments in licensed fuel performance codes, to stay at the state-of-the-art
Integration or coupling with TRACE and PARCS
FRAPTRAN dynamic time stepping based on back-stepping and normalized change metric, as well as output to the console to inform the user on status of calculation
September 18, 2018
User Group Meeting | 2015 | Zurich, CH

11. User Group Meeting | 2015 | Zurich, CH
Next Code Release
Plan to release FRAPTRAN-2.0 (same predictions with modern FORTRAN) in late 2015 / early 2016
Plan to release FRAPCON-4.1 and FRAPTRAN-2.1 by December 2016
September 18, 2018
User Group Meeting | 2015 | Zurich, CH