Sponsored by the U. S. Nuclear Regulatory Commission Volume 13 / Number 1 / December 2013

This is a report on TRACE user problems and resolutions. Open trouble reports identified in the previous newsletters with no new progress are not discussed, but can be found in the TRACE trouble report system (TRACEZilla) on the NRC Codes website (https://www.nrccodes.com).
For the time period between January 1, 2013 and December 31, 2013, 31 new trouble reports were submitted to TRACEzilla. 69 trouble reports were either resolved or closed during this same time period. As of December 31, 2013, there are 672 trouble reports in the TRACE bug reporting system; 21 of those are open, with the remainder resolved, closed, or duplicates. This implies that ~97% of the TRACE trouble reports have been resolved or closed or duplicates.
A resolved trouble report indicates that it has been addressed with an update or documentation change that is pending. A closed trouble report indicates that it has either been addressed by successfully re-running the test problem(s) of interest with a current version of TRACE or it has been closed by incorporating a pending update into the NRC developmental version of TRACE. A pending update implies that it has been tested, documented, reviewed, and submitted to the NRC, but has not been included in the developmental version of
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Thermal-Hydraulic

Code News
Committed to the support of the

T/H Codes User Community

Contents:

• 
  Fall CAMP Meeting
  
• 
  TRACE User Problems
  
• 
  Recent RELAP5 User Problems
  
• 
  Items of Interest
  

Website:

https://www.nrccodes.com

Fall 2013 CAMP Meeting …continued from page 1
members are performing is a very high priority for NRC in providing oversight of reactor licensees and applicants, and helping the NRC accomplish its safety mission. Ms. Gibson discussed how the CAMP program benefits both the NRC and CAMP members.
Member contributions have leveraged NRC resources, improved the codes, and improved modeling. Examples include areas such as identifying code errors and plant modeling for new applications. Programs have provided a venue for members to develop and share knowledge about thermal-hydraulic safety analysis. The user community and the quality of the analysis codes benefit through the network effect of the program.
As TRACE matures, CAMP will be an important contributor to its future development and assessment, and CAMP membership is expected to continue to expand based on increased nuclear activities worldwide. As evidence, two new CAMP members were announced: Netherlands and Vietnam.
Carl Thurston then welcomed the CAMP members and thanked them for supporting the CAMP program. Of the 56 attendees at this meeting, there were 35 international members and 20 NRC staff. 33 presentations were provided at this meeting.
Carl motioned to accept the meeting minutes from the Spring 2013 CAMP meeting. Chester Gingrich seconded the motion, and the minutes were accepted.
Carl introduced Marlin Strand and thanked him for supporting the Fall 2013 CAMP Meeting. Marlin introduced the evening activities for the CAMP meeting, and welcomed everyone to Washington, DC.
The first technical presentation was given by Dr. Chris Hoxie of the USNRC. Dr. Hoxie gave a presentation on the Status of NRC Code Development. CAMP related contacts at the NRC were provided as follows:

• 
  CAMP Program: Carl.Thurston@nrc.gov
  
• 
  NUREG/IA: Kirk.Tien@nrc.gov
  
• 
  CAMP Code Distribution: Christopher.Murray@nrc.gov
  
• 
  TRACE: Christopher.Murray@nrc.gov
  
• 
  SNAP: Chester.Gingrich@nrc.gov
  
• 
  PARCS: Nathanael.Hudson@nrc.gov
  
• 
  RELAP5: Joseph.Staudenmeier@nrc.gov
  

Dr. Hoxie described the major elements of the “Reactor Core and System Analysis Code Suite”. The codes included in this suite include SNAP (platform/graphical user interface), Triton/Helios/CASMO and GenPMAXS (cross section library generation), PARCS & PATHS (core physics and steady state thermal hydraulics) and TRACE (reactor system thermal hydraulic analysis).

Dr. Hoxie provided an overview of NRC/ISL presentations at this meeting. In addition, he provided a brief overview of recent TRACE development, PARCS / PATHS / GenPMAXS development and SNAP development, along with a brief status summary for RELAP5.
Dr. Hoxie presented information on the PWR TRACE modeling guidelines. The modeling guidelines are a document that presents a complete set of recommendations for inputs specific to PWR plant models for Westinghouse, Combustion Engineering, and Babcock & Wilcox type designs currently operating in the U.S. The modeling guidelines are being developed to (1) codify “best practices” for PWR modeling, (2) serve as a training tool, and (3) help highlight areas of need or guide future investigation. The modeling guidelines will be used to (1) form a consensus on how specific PWR plant models are to be built, and (2) potentially provide assistance in modeling other PWR designs, though the strict applicability of the guidelines is currently limited. The guidelines will ultimately be translated to test facility modeling to ensure that all modeling details are consistent between plant and assessment models. The PWR TRACE modeling guidelines are available now on the NRCCodes Sharepoint site (https://www.nrccodes.com). The NRC is seeking CAMP member feedback for these guidelines. Dr. Hoxie also mentioned that there is ongoing work to develop BWR Modeling Guidelines.
TRACE is used at the NRC for licensing support and design certification activities: ESBWR, US-EPR, US APWR, AP1000, ABWR, Integrated PWR pre-application phase, power uprates for operating reactors and Generic Safety Issue (GSI) support.
Dr. Hoxie presented the release dates for TRACE V5.0 Patch 02 and 03, and indicated that Patch 04 is being finalized and should be ready for release in early 2014, less than two years after the Patch 03 release. It is strongly recommended that CAMP members upgrade to Patch 03, which is more robust and has better CPU performance. Dr. Hoxie showed a graph of CPU performance for a SBLOCA transient, and the improvement with Patch 03 was quite significant.
Lastly, Dr. Hoxie reminded CAMP members that TRACE is the future of NRC safety systems thermal hydraulic analysis. The NRC would like CAMP members to focus their assessments on TRACE, and suggested the following areas: fuel rod models, grid spacer models, pre-CHF droplet field void fraction predictions and additional integral tests.
Next, Chris Murray (USNRC) gave a presentation on TRACE Code Development Status. TRACE follows a system of releasing major versions followed by periodic numbered patch releases. Patch release history is as follows:

• 
  V5.0 Patch Release 01 (10/17/2008)
  
• 
  V5.0 Patch Release 02 (06/02/2010)
  
• 
  V5.0 Patch Release 03 (05/11/2012)
  
• 
  V5.0 Patch Release 04 (early 2014)
  

Focus for TRACE is on making the code more robust as well as key modeling improvements.

Presently there are 650 total trouble reports in our tracking system (as of 10/24/2013). 578 trouble reports are closed out, 56 trouble reports are considered resolved, but not yet closed out, and 16 trouble reports are open. Since the last CAMP meeting 30 new developmental code versions have been created, 24 new unique trouble reports were submitted, 44 trouble reports have been resolved or closed out.
Chris Murray then described some of the more significant changes that have gone into TRACE since the last CAMP Meeting (from V5.750 to V5.823). The major changes include fuel rod model improvements, usability enhancements, uncertainty quantification, CONTAN improvements and other bug fixes. In addition, the PARCS source in TRACE was updated to v32m11, which went into TRACE V5.771.
Users can see a snapshot of the recent TRACE development activity on https://www.nrccodes.com using the Build page. Planned fixes or updates are listed in the Holding Bin. TRACE V5.0 Patch 4 is planned to be released in March 2014.
Doug Barber then reported on the RELAP5/MOD3.3 status. The latest full release is RELAP5/MOD3.3Patch04, which is Version 3.3iy, October 2010. The most recent developmental version is 3.3js. A table showing the code names, version numbers and release dates for all RELAP5/MOD3.3 releases was provided.
Resolution for one user problem was reported and discussed. UPN 2013-05 from Wojtek Baltyn dealt with code indexing errors when processing input from the radiation enclosure cards. In addition, there were several bugs related to compilation with the g77 compiler that were addressed. The features implemented as fixes to resolve this user problem were made Version 3.3js. User problems continuing to be worked and on hold were also briefly discussed.
Since 1998, 417 user problems have been reported: 298 are resolved, 30 are in work, 28 are on hold and three are not resolvable. A complete list of user problems from 1998 to date is posted on the NRCCodes Sharepoint site (https://www.nrccodes/com). RELAP5 priorities from the Spring 2013 TPC meeting were presented and briefly discussed.

Additional presentations included:

• 
  Dr. Nathanael Hudson, US NRC, “PARCS Status and Updates”
  
• 
  Chester Gingrich, US NRC, “SNAP Status and Updates”
  
• 
  Dr. Jennifer Uhle (presented by Dr. Joseph Staudenmeier), US NRC, “Regulatory Use of Thermal Hydraulic Systems Analysis Codes”
  
• 
  Chester Gingrich & Dr. Steve Bajorek, US NRC, “TRACE Uncertainty Quantification Demonstration”
  
• 
  Ilijana Ivekovic, ENCONET, “CAMP Activities in Croatia”
  
• 
  Dr. Andrej Prosek, Josef Stefan Institute, “Status of CAMP Activities in Slovenia”
  
• 
  Dr. Ernest Staron, National Atomic Energy Agency of Poland (PAA), “CAMP Related Activities in Poland 2013”
  
• 
  Dr. Aeju Cheong, Korea Institute of Nuclear Safety (KINS), “Status of CAMP Activities in Korea”
  
• 
  Yu Chiang, Institute of Nuclear Engineering and Science, “Status of CAMP Activities in Taiwan”
  
• 
  Sean Roshan, Royal Institute of Technology, KTH, “Status Report of CAMP Activities in Sweden”
  
• 
  Markus T. Schlenker, Karlsruhe Institute of Technology, “Determination of Equilibrium Cycles for Reduced Moderation BWR with PARCS and Assessment of Reactivity Coefficients”
  
• 
  Dr. Stephanie P. Bush-Goddard, US NRC, “The Radiation Protection Code Analysis and Maintenance Program (RAMP)”
  
• 
  Dr. Fulvio Mascari, ENEA (Remote Presentation), “Analyses of Natural Circulation Phenomena Typical of the MASLWR by using the TRACE V5 Code”
  
• 
  Dr. Victor Sanchez, Karlsruhe Institute of Technology (KIT), “Extension of GenPMAXS to Support the Monte Carlo Lattice Code SERPENT2 Beta”
  
• 
  Dr. Patrick Raynaud, US NRC, “Core-Wide Estimates of Fuel Dispersal During a LOCA with FRAPCON/ FRAPTRAN and TRACE”
  
• 
  Petr Heralecky, TES s.r.o., “Post-Test Analysis of Upper Plenum Break 11% at PSB VVER Facility using TRACE V5.0 and RELAP5 MOD3.3”
  
• 
  Dr. Yong Jin Cho, Korea Institute of Nuclear Safety, “Progress Report - TRACE Assessment for PASCAL Local Condensation Experiment”
  
• 
  Pavel Kral, UJV Rez, “Analysis on Condensation Models in RELAP and TRACE”
  
• 
  Dr. Aaron Epiney, Paul-Scherrer Institute, “PSI TRACE/PARCS Methodology for Steady-State BWR Analyses”
  
• 
  Dr. Konstantin Nikitin, KKM, Switzerland, “Minimal Requirements to the Thermal-Hydraulics/Neutronics Mapping for BWR/6 ATWS”
  
• 
  Joshua Whitman, US NRC, “New TRACE Feature: Adaptive User-Independent Time-Step Optimization (AUTO)”
  
• 
  Joshua Whitman, US NRC, “Changes to TRACE Error and Warning Messages”
  
• 
  Tetsuhiro Ozaki, Nuclear Fuel Industries, Ltd., “Validation of TRAC-BF1 Code and Estimation of Interfacial Shear Uncertainty”
  
• 
  Dr. Nathanael Hudson, US NRC, “PATHS: Updates, Assessments, and Status”
  
• 
  Haejung Sung, KEPCO, “TRACE Assessment using VAPER Tests”
  
• 
  Dr. Suk K. Sim, Environment & Energy Technology, Inc., “Investigation of the Loop Seal Clearing Phenomena for the ATLAS DVI /CL SBLOCA Tests using MARS-KS”
  
• 
  Dr. Masahiro Furuya, CRIEPI, “Code Validation for Rapid Flow-Decrease Event in SIRIUS-F Facility which Simulates ABWR”
  
• 
  Dr. Masahiro Furuya, CRIEPI, “Investigation of Fukushima Daiichi Accident with TRACE Code”
  

Social activities during the CAMP Meeting included a social hour on Wednesday evening and a wine tasting followed by a tour of the Phillips Collection on Thursday evening. The Spring 2014 CAMP Meeting will be held at the University of Zagreb in Croatia.

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