1. IRUG Member Meeting 2011 RELAP5 International Users Seminar July 25-28, 2011 Salt Lake City, UT

2. Agenda • Acceptanceof September 2010 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 August 2010 - June 2011 100 reported/worked-on Resolved (34) On-Hold (48) Resolved: Work has been completed on user problem, update has been submitted, and update is 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 (18)

7. Selected User Problems

8. Problem 10039 • Symptom: If the number of junctions on the branch input card (CCC0001) is entered as a real instead of an integer, the code fails ungracefully with no error messages in the output file. There is no input processing in the output file for the affected component.Thiswas found in RELAP5-3D versions 2.9.4 and 2.9.5; this affects some earlier RELAP5-3D versions. • Root Cause: Error is in an ‘if test’ on the variable ‘ltype’ in subroutine INP2N • Resolution: Resolved. The erroneous ‘if test’ was fixed, the fix worked correctly. The code now prints out error messages indicating that an integer must be used in the output file.

9. 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: The ‘if tests’ in the "to junction" coding were switched. • Status: Resolved. Corrections were made to two subroutines, STGODU and BRNTRN. The ‘if tests” were corrected. In addition, minor changes to the debug printout in subroutine STGODU were made to clean up the coding. Test cases included the square density wave problem described in Kuo’s original report and the AP600 model. Both test cases ran satisfactorily.

10. Problem 11005 • Symptom: In running a two parallel pipe problem connected at the bottom and top with single junctions the initial liquid level in each pipe should be in volume 6, but pipe 622 detects the level in volume 7. • Root Cause: An incorrect ‘if test’. • Status: Resolved. The bits in variable ‘vctrlx’ were found to be set incorrectly. Glen Mortensen provided a fix for subroutine ILEVEL. The problem now correctly detects the level in volume 6.

11. Problem 11011 • Symptom: A test problem simulating a canal draining accident reached heat structure temperatures that were greater than the maximum values used in the material composition data. However, the code did not fail when the 2D conduction model was used. The code did fail as expected when the 2D conduction model was not used. • Root Cause: No error checking for heat structure temperatures exceeding the material composition data. • Status: Resolved. Added error checking to subroutine MDATA2, but the problem still did not fail. Also had to add some error checking to subroutines HT2TDP and QFMOVE. The problem now fails gracefully with an error message indicating that the maximum temperature has been exceeded.

12. Problem 11019 • Symptom: An INL user reported that the code was not accurately predicting the pressure drop for a large, horizontal pipe in laminar flow. The pipe was 60 m long and had a diameter of 0.4996 m. The pressure, temperature, and Reynolds number were 5.0 MPa, 500 K, and 995, respectively. • Root Cause: Truncation error. • Status: Resolved. The error was traced to the truncation of small differential pressures in the momentum solution to prevent velocity spin-ups. The problem was corrected using Option 29 which solves the momentum equation for low velocities.

13. 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