1. www.inl.gov 2010 RELAP5 International Users Seminar September 20-23, 2010 West Yellowstone, Montana IRUG Member Meeting

2. Agenda Acceptance of August 2009 meeting minutes Status of IRUG Membership Old Business – Status of User Problems – Selected User Problem Descriptions New Business – Schedule for code release – Other items Election of New Chair Adjourn Status

3. IRUG Member Status Members: Bechtel Marine Propulsion Corporation (KAPL/Bettis) NRI-Rez Areva NP General Dynamics Electric Boat INSS Rolls-Royce Mitsubishi Heavy Industries Participants: Arizona Public Service Newport News Nuclear Engineering LTD (Japan) Nuclear Engineering LTD JNES Oak Ridge National Lab ILD Power KIT Institute of Nuclear Energy Research (China)

4. Current University License Holders Oregon State Univ. Texas A&M Univ. U. of Catalonia Univ of Pisa U. of Michigan Idaho State Univ. Univ. of Tennessee Univ of Massachusetts Ohio State U. Of Illinois-UC Florida International Universidade Federal de Minas Gerais Univ Of Wisconsin UC Berkeley

5. National Laboratories ORNL LANL ANL LLNL

6. User Problem History July 2009 - July 2010 176 reported/worked-on Resolved: Work has been completed on user problem, update has been submitted, and update is in latest developmental version Solved:Work has been completed on user problem, update has been submitted, but update is not in latest developmental version In-Work: Work on user problem is currently being carried out On-Hold: Work has not begun on user problem, or work was began on user problem but work is now stopped on user problem In-Work (53) Solved (0) On-Hold (34) Resolved (89)

7. Selected User Problems

8. Problem 00041 Symptom: Many nodal kinetics input models require more memory than code has available; this necessitates updating code to increase size of FAST array. Problem was found in version 1.1 (cf02); affects all earlier versions and some later versions. Root Cause: Maximum size of FAST array was a fixed number. Resolution: Resolved. During FORTRAN 95 conversion, allocates were used after reading in input model. At this point, the code knows the size an array needs to be for a given input model. Update appeared in version 2.9.2.

9. Problem 06035 Symptom: System calculation using 3D hydro (multid) components fails in input processing in BPLU solver reordering. Calculation runs with MA18 solver. Problem was found in version 2.4.1; affects all earlier versions and some later versions. Root Cause: BPLU solver arrays are dimensioned too small. Resolution: Resolved. During FORTRAN 95 conversion, BPLU solver arrays are now allocated. Update appeared in version 2.9.4.

10. Problem 10016 Symptom: Simple ATR heat transfer problem fails on second problem of stacked job when heat conduction enclosure model is used. Both problems run when enclosure model is commented out. Error message says number of conduction sets does not agree with number requested. This was found in version 2.9.4; this affects some earlier RELAP5-3D versions. Root Cause: Variable ‘l3a(1)’ in subroutine RRADHT was not reset properly when running stacked cases. Resolution: Resolved. Added line ‘l3a(1) = 60000000’ at beginning of subroutine RRADHT. Update appeared in version 2.9.5.

11. Problem 10024 Symptom: HTGR calculation fails with multiple thermodynamic property failures when axial conduction model is used together with implicit heat transfer coupling. Failures do not occur when explicit coupling is used or when implicit coupling is used without axial conduction. This was found in version 2.9.4; this affects some earlier RELAP5-3D versions. Root Cause: Variables ‘htc2x’ and ‘htb2x’ were set incorrectly in subroutine HT2TDP. Status: Resolved. Fixed subroutine HT2TDP coding. Update appeared in version 2.9.5.

12. Problem 10031 Symptom: In comparing Groeneveld et al. CHF table in code (subroutine CHFTAB) to 1986 paper, errors were found. Errors go back to RELAP5/MOD3. Root Cause: Errors introduced when reading numbers from paper and typing them into code. Status: Resolved. Fixed subroutine CHFTAB by electronically reading pdf file numbers (from paper) and converting them into ascii numbers. There were 41 errors; 15 potentially significant (differences of 1.3% and greater); rest all having differences less than 0.5%. Update appeared in version 2.9.5.

13. Problem 10041 Symptom: In running system problem, an error regarding variable ‘conv’ was found in subroutine RTMDV; coding is correct in subroutine RTMDJ. Error was found in version 2.4.1. Error goes back to RELAP5/MOD1. Root Cause: An ‘if test’ on variable ‘conv’ was missing in subroutine RTMDV. Status: Resolved. Fixed subroutine RTMDV to add ‘if test’ on variable ‘conv’ as is done in subroutine RTMDJ. Update appeared in version 2.9.5.

14. Problem 10043 Symptom: Code gave same results with and without Card 1 Option 23, which turns on Godunov scheme for boron tracking. Error was found in version 2.4.1. Fixing inverted junction table errors in subroutines STGODU and BRNTRN in RELAP5/MOD3.2.1.2, that were fixed in version 2.4.1, shows the same bad result. Root Cause: Unknown. Status: In-Work. Coding is under investigation. Code manual implies Godunov scheme gives better results than default upwind difference scheme, however AP600 experience found Godunov scheme is not reliable at steady state; thus it was not chosen as default scheme. Manual was modified.

15. Problem 10044 Symptom: Code gave severe oscillations for the offtake model for larger small breaks. Subroutine HZFLOW calculates mass flux based on max of volume mass flux and junction mass flux. Subroutine PHANTV calculates mass flux based on volume mass flux. For a large enough break, junction mass flux can exceed volume mass flux; this can lead to inconsistent interpolations. Error was found in version 2.4.1. Error was introduced in RELAP5/MOD3. Root Cause: Inconsistent interpolations. Status: In-Work. An update has been developed, and it is currently being tested.

16. Next Code Version Release Last Released IRUG Version was 2.4.3 FORTRAN 95 Version 3.0 Ready for Beta version release to IRUG Members Receipt of the Code Will Require a Beta Version License Beta Version Will be Executable With Approximately a Three Month License File Large Number of New Features and Capability Have Been Added in Addition to the FORTRAN 95 Programming Language Change

17. RELAP5-3D CHANGES SINCE VERSION 2.4.3 RELAP5-3D Changes/New Features Since Version 2.4.3 New Features – FORTRAN 95 – Restructuring with FOR_STRUCT – Developmental Assessment – Improved Time Step Control – Improved Nodal Kinetics – Institutionalized Card 1, Option 3 (Consistent Sound Speed Calculation between Volumes and Junctions when Noncondensables are Present)

18. RELAP5-3D CHANGES SINCE VERSION 2.4.3 (cont.) – Allow Efficiency Multiplier (for Type-3 Turbine) using a Control Variable and Turbine Inlet Junction Form Loss Multiplier using a Control Variable – Allow PVM Coupled Restart from Uncoupled Runs – Modified PVM Coupling to send any RELAP5-3D Nodal Kinetics Variable instead of the Restricted List of Power, Zone, Heat Structure Average Temperature, etc. – Added Card 1 Option 27 to set Theta Velocity in Outermost Ring of Rigid Body Rotation and R-theta Symmetric Problems to 1.0 m/s – Added Card 1 Option 29 to allow more Accurate Solution to Momentum Equations for Low Flows – Allow Fluid Interactive Capability for the Working Fluid D2O – Allow Input Options NEW and NEWATH to use all Working Fluids

19. RELAP5-3D CHANGES SINCE VERSION 2.4.3 (cont.) – ANS 2005 Decay Heat Standard – Pump Head and Torque Multiplier as a Function of Pressure and Void Fraction – CO2 Properties Improvement for Running near and through the Critical Point – Improved Compressor Model (Allow Input Negative Flows on Speed Tables, Allow Compressors to Run with Noncondensable Gases) – Added Command Line Argument ‘-stat’ for Run Statistics for Developmental Assessment

20. RELAP5-3D CHANGES SINCE VERSION 2.4.3 (cont.) – 2D Heat Conduction Model without Reflood – Alternate Heat Structure – Fluid Coupling Model – Linux SUSE Platform Capability – R5FORCE Windows PC Platform Capability – PVM Coupling Junction – Fluids DOWTHERM A and R134a (SUVA) – Added Card 1 Option 71 to allow Improved Metastable Extrapolation into Superheated Liquid – Added Additional Mass Error Edits – AptPlot Capability