International RELAP5 User Group (IRUG)

International RELAP5 User Group

The International RELAP5 User Group (IRUG) comprises organizations licensed to use the RELAP5 nuclear power plant safety analysis code, developed at Idaho National Laboratory (INL) since 1979. The objective of IRUG is to serve industry, government, and academia by providing and maintaining a versatile RELAP5 package for safety and engineering analyses of nuclear power reactors. IRUG oversees RELAP5–3D improvements, ensuring it remains a leading reactor safety systems code.

What does IRUG provide?

IRUG provides access to RELAP5-3D on INL's supercomputers, auxiliary software, user group meetings, training, and support for input design and debugging. Members can report issues via User Trouble Reports. Annual meetings, held at INL or member facilities, feature training, technical presentations, business updates, and voting on code and group matters.

Who can be an member?

Membership is open to individuals and organizations, including governmental entities, commercial companies, and academic institutions. Requests for access must be vetted by the Nuclear Computational Resource Center (NCRC). Membership fees, based on usage level (from basic to superuser), are charged annually and adjusted as needed.

Who leads IRUG?

IRUG is led by a chairman, vice-chairman, and secretary. Voting rights are based on membership level, and meeting minutes are distributed prior to each meeting.

International RELAP5 User Group (IRUG) Meeting 2026

May 18–21, 2026 | Idaho Falls, Idaho

Choose your session

Whether you’re new to RELAP5-3D or looking to expand your expertise, there’s a session designed to meet your needs.

Training Workshop Requirements

To participate in either training workshop, attendees must:

If you need to obtain a RELAP5-3D license, please submit a code request at: https://www.inl.gov/ncrc

Registration Deadlines

(Training Workshops Only)

Early registration is encouraged, as space may be limited.

Contact Us

RELAP5-3D Project Coordinator:
[email protected]

Registration Information:
[email protected]
[email protected]

Foreign National Access Plan:
[email protected]

Past IRUG Seminars

Idaho Falls 2025 Meeting

The 2025 IRUG meeting was held on July 28 – August 1, 2025 in Idaho Falls, ID.

The 2025 International RELAP5-3D User Group (IRUG) Meeting will feature the release of RELAP5-3D version 4.6.2 and the new RELAP5-3D/MOOSE Coupling.

Park City 2024 Meeting

The 2024 IRUG meeting was held on Sept. 9-13 in Park City, Utah.

Links to presentations will be available soon.

Idaho Falls 2023 Meeting

The 2023 IRUG meeting was held on December 4 – 8, 2023 in Idaho Falls, ID.

Links to presentations will be available soon.

Idaho Falls 2021 Meeting

The 2021 RELAP5-3D Training Workshop and Users Group Seminar was held virtually on September 13 – 17, 2021. There were 15 technical presentations and the meeting included basic and advanced RELAP5-3D training classes. The meeting provided a forum for RELAP5 users from around the globe to share their experiences in developing models and performing analyses using the code. In addition, the latter part of the seminar was set aside for an executive meeting of the International RELAP5 Users Group. Membership in the User Group was not a condition for attendance at the seminar, and technical papers were encouraged based on any version or application of RELAP5. IRUG 2021 Agenda

Name	Authors	Organization
Application of RELAP5-3D for Liquid Metal Reactor Safety	Giannetti, Narcisi, Ciurluini, Caruso	Sapienza Universita Di Roma
Application of RELAP5-3D to High Energy Deposition Transients within TREAT	Blakely	INL
Application of Surrogate Models for Best Estimate Plus Uncertainty Analysis by RELAP5 Code	Kinoshita	INSS
Development of Best Estimate Plus Uncertainty (BEPU) Application for RELAP5-3D	Choi, Parisi	INL
Human Reliability Analysis	Boring	INL
JAEA HTTR Secondary System Modeling	Anderson	INL
Modern Error Scaling	Epiney	INL
Plutonium Fuel Services Irradiation Experiment in the Advanced Test Reactor	Fishler	INL
Regression Testing for BR2 RELAP5 Models	Lin, Garner, Licht, Wols	ANL, SCK-CEN
RELAP5-3D Architectural Upgrades through Gnu Fortran Adaptation	Mesina	INL
Remote RELAP5-3D Information	Mesina	INL
Risk-Informed ATF Analysis for Generic PWR & BWR	Zhang, et al	INL
Thermal-Hydraulic Modeling of MARVEL Microreactor	Parisi	INL

Idaho Falls 2019 Meeting

The 2019 RELAP5-3D Training Workshop and Users Group Seminar was held in Idaho Falls, Idaho USA from April 15 – 19 2019. There were 20 technical presentations. The meeting also included an advanced RELAP5-3D training class. The meeting provided a forum for RELAP5 users from around the globe to share their experiences in developing models and performing analyses using the code. In addition, the latter portion of the seminar was set aside for an executive meeting of the International RELAP5 Users Group. Membership in the User Group was not a condition for attendance at the seminar, and technical papers were encouraged based on any version or application of RELAP5. 2019 IRUG Agenda

Name	Authors	Organization
Accident Tolerant Fuels – A PRA Comparison	Mandelli, et al.	INL
Analysis of Accident Tolerant Fuel Using RELAP5-3D	Parisi, et al.	INL
Analysis of the Versatile Test Reactor Using RELAP5-3D	Parisi, et al.	INL
Analysis Using RELAP5-3D as Compared with a Test Mockup	Scherrer	GDEB
Bison-TRACE Coupling	Gardner, et al.	INL
Development of Quantitative Verification Capabilities for use with RELAP5-3D and R5EXEC	Buschman	Bettis
Direct Sparse Matrix Linear Solver for the Nodal Kinetics in RELAP5-3D	Barber	ISL
Dynamic PRA of a Multi-unit Plant	Mandelli, et al.	INL
FPoliSolutions RISA Technology Status and Path Forward	Frepoli	FPoliSolutions
Jacobian Consistency Tool for RELAP5-3D	Mesina	INL
RELAP5-3D – the Path Forward	Wolf, et al.	INL
RELAP5-3D Application to Risk-Informed Systems Analysis	Choi	INL
RELAP5-3D Software Licensing Updates	Baker	INL
RELAP-7 Development Status	Martineau	INL
Selected User Problems	Anderson	INL
Six-Field Model and RELAP5-3D	Roth, Mesina	ISL, INL
TWERL for TREAT Pre-Conceptual Design	Epiney	INL
Upgrade to GFORTRAN and FORTRAN 2003	Mesina	INL
Validation of a Simple RELAP5-3D Point Kinetics Model of the Full-Slotted MARCH Core in TREAT	Davis	INL
Validation of RELAP5-3D Using HE-FUS3 Data	Davis	INL

Idaho Falls 2018 Meeting

2018 RELAP5-3D Training Workshop and Users Group Seminar The 2018 RELAP5-3D Training Workshop and Users Group Seminar was held in Idaho Falls, Idaho USA from April 30 – May 4 2018. There were 20 technical presentations. The meeting also included an introductory RELAP5-3D training class and a half day of training on RAVEN. The meeting provided a forum for RELAP5 users from around the globe to share their experiences in developing models and performing analyses using the code. In addition, the latter portion of the seminar was set aside for an executive meeting of the International RELAP5 Users Group. Membership in the User Group was not a condition for attendance at the seminar, and technical papers were encouraged based on any version or application of RELAP5. IRUG 2018 Agenda

Name	Authors	Organization
Acceleration of UQ and PRA with RAVEN Hybrid Modeling of a Blend of Surrogate and RELAP5-3D Models	Alfonsi, et al.	INL
Advancements of PHISICS – RELAP5-3D Package for Time-Dependent Transient Calculations	Alfonsi, et al.	INL
Application of RELAP5-3D for the Risk Informed External Event Analysis	Parisi, et al.	INL
Consistent Fluid Property Evaluation for RELAP5-3D	Mesina	INL
Development of New H2O95N Fluid Properties	Forsmann	INL
Integrating Classical PRA Models into RELAP5-3D	Mandelli, et al.	INL
Kinetics Advances in RELAP5-3D	Barber	ISL
Measuring Risk Importance in a Dynamic PRA Framework Using RAVEN – RELAP5	Mandelli, et al.	INL
Multi-Physics Best Estimate Plus Uncertainty (MP-BEPU) Analysis Framework LOTUS and RELAP5-3D	Zhang	INL
Ongoing RELAP5-3D Related Activities at SCK-CEN	Castelliti	SCK-CEN
PbLi Equations of State	Humrickhouse	INL
RELAP5-3D Backup Improvements	Anderson	INL
RELAP5-3D Licensing Updates_Smith_INL	Smith	INL
RELAP5M3_3 – RELAP5-3D – CFD Calculation of Reactor Downcomer Velocity and Temperature Fields in PTS Analyses	Kral, et al.	UJV Rez
RELAP7 Progress and Future	Martineau	INL
Selected User Problems	Anderson	INL
Selected User Problems_Choi	Choi	INL
System Modeling of the HTTR with RELAP5-3D	Humrickhouse	INL
Timing Studies of Recent RELAP5-3D Code	Mesina	INL
Validation of a Detailed RELAP5-3D Model of TREAT	Davis	INL

Idaho Falls 2016 Meeting

2016 RELAP5-3D Training Workshop and Users Group Seminar The 2016 RELAP5-3D Training Workshop and Users Group Seminar was held in Idaho Falls, Idaho USA from October 3-7 2016. There were 19 technical presentations. The meeting also included an Advanced RELAP5-3D training class and a day of training on RAVEN. The meeting provided a forum for RELAP5 users from around the globe to share their experiences in developing models and performing analyses using the code. In addition, the latter portion of the seminar was set aside for an executive meeting of the International RELAP5 Users Group. Membership in the User Group was not a condition for attendance at the seminar, and technical papers were encouraged based on any version or application of RELAP5. 2016 IRUG Agenda

Name	Authors	Organization
2016 User Problems	Anderson	INL
2016-irug-agenda
A Statistical Method for Benchmarking Nuclear Plant Models	McCloskey, Smith	BMPC
Equations of State for PbLi	Humrickhouse	INL
FLASHback – RELAP at Fifty(Paper)	Martin	BWXT
FLASHback – RELAP at Fifty(Presentation)	Martin	BWXT
Improvements to PHISICS_RELAP5-3D Capabilities for Simulating HTGRs	Balestra, Alfonsi, Strydom, Rabiti, Giannetti, Caruso	INL, Sapienza University or Rome
Jacobian Matrix Analysis Tool for RELAP5-3D	Mesina	INL
Modification to the Condensation Model in the Presence of Noncondensables	Anderson	INL
RELAP5 3D Simulations of Hot Leg Break LOCA Scenarios	Vaghetto, Vanni	Texas A & M University
RELAP5-3D Analyses for the US-DOE LWRS RISMC Program, Industry	Parisi, Prescott, Coleman, Szilard	INL
RELAP5-3D Licensing Updates	Smith	INL
RELAP5-3D Two-Phase Behavior and Predictions at Low Pressures	Castelliti	SCK CEN
RELAP-7 Current Status and Future Development	Martineau	INL
Risk-Informed Safety Margin Characterization	Epiney, Zhang, Parisi, Szilard	INL
Seismic Loop LOCA with Double-ended Guillotine Break at IPT Inlet and Outlet	Roth	INL
Thermal Hydraulic Analysis of a Gas-Cooled Reactor	Bayless	INL
Thermal-Hydraulic Analysis of a Versatile Coupled Test Reactor	Davis	INL
Update on RELAP5-3D CHF Geometry Correction Factors	Choi	INL
Use of Systems Analysis Codes in the Nuclear Industry	Sharpe	INL

Idaho Falls 2015 Meeting

International RELAP5 Users Group (IRUG) Seminar and Meeting

The 2015 RELAP5 Users Group Meeting was held from August 13 – 14, 2015 in Idaho Falls, ID. There were over 20 technical presentations. The meeting was preceded by an Advanced RELAP5-3D training class.

The meeting provided a forum for RELAP5 users from around the globe to share their experiences in developing models and performing analyses using the code. In addition, the latter portion of the seminar was set aside for an executive meeting of the International RELAP5 Users Group. Membership in the User Group was not a condition for attendance at the seminar, and technical papers were encouraged based on any version or application of RELAP5.

Name	Authors	Organization
Demonstration of BEUP Analysis of LB-LOCA with RELAP5-3D for High Burnup Fuel	Zhao	INL
Development of a Quality Assured HTTF RELAP5-3D Input Model	Bayless	INL
Developmnet of a RELAP5-3D Property Library for Use by Other Computer Codes	Davis	INL
Dual Number Differentiation in RELAP5-3D	Hodson	Utah State University
H2ON Property Table Errors UP-15020	Forsman	INL
Impact of Pressure Relief Holes on Core Coolabilityfor a PWR During a Larege-Break LOCA With Core Blockage Using RELAP5-3D	Vaghetto	Texas A & M
Improvements – Multi Deck and Strip Features	Mesina	INL
Improvements in Sequential Verification	Mesina	INL
IRUG 2015 Agenda
Jacobian Evaluation Project	Mesina	INL
Modeling Moving Systems With RELAP5-3D (Watch)	Buschman	Bettis
Modeling the SCO2 Power Cycle of a generic dual Coolant Fusion Reactor With RELAP5-3D	Batet	Politecniacade University of Catalunya
moving-motion-video-buschman-bettis
Phisics-RELAP5-3D Coupled Suite for Industry Applications	Alfonsi	INL
Qualitative and Quantitative Evaluation of Coupling Approaches for Coupling RELAP5 and LabView	Pack	University of Idaho
RELAP5 Applications at GRNSPG – NINE_ Thirty Years of Activities	Lanfredini	NINE
RELAP5-3D Auxiliary Tools – 2015 Update	Forsman	INL
RELAP5-3D Gas-Cooled Reactor Activities	Bayless	INL
RELAP5-3D Software Licensing Updates	Smith	INL
RELAP-7 Code Development Status Update for 2015	Zhao	INL
SCREED – A Supporting Tool for V-V and Uncertainty Evaluations of Best Estimate System Codes for Licensing Applications	Lanfredini	NINE
Six Field Governing Equations for RELAP5	Roth	University of Idaho
The BEPU Evaluation Model with RELAP5-3D for Licensing nthe Atucha II NPP	Landfredini	NINE
Thermal-Hydraulic Analysis of an AHTL In-Pile Tube in the Southwest Loop of the ATR	Davis	INL
User Problems-Version Features	Anderson	INL
Validation of a RELAP5-3D Point Kinetics Model of Treat	Davis	INL

Idaho Falls 2014 Meeting

International RELAP5 Users Group (IRUG) Seminar and Meeting The 2014 RELAP5 Users Group Meeting was held from September 11-12 2014 in Idaho Falls, ID. There were 20 technical presentations. The meeting was preceded by an Advanced RELAP5-3D training class. The meeting provided a forum for RELAP5 users from around the globe to share their experiences in developing models and performing analyses using the code. In addition, the latter portion of the seminar was set aside for an executive meeting of the International RELAP5 Users Group. Membership in the User Group was not a condition for attendance at the seminar, and technical papers were encouraged based on any version or application of RELAP5.

Name	Authors	Organization
A Quantitative Approach for Making Qualitative Assessment Judgments	Davis Roth	INL ISL
Application of RELAP5 to the BR2 and RHF Research Reactors for the GTRI Fuel Conversion Project	Licht	ANL
BWR Probabilistic Risk Analysis using RELAP5-3D and RAVEN	Rabiti, Riley, Alfonsi, Mandelli, Rinaldi, Nielsen, Cogliati, Smith	INL
Capabilities of PHISICS/RELAP5-3D	Alfonsi, Rabiti, Epiney	INL INL Paul Scherrer Institute
HTTF RELAP5-3D Applications and Assessment	Bayless	INL
Impact of Pressure Relief Holes on Core Coolability for a PWR During a Large-Bread Loss of Coolant Accident With Core Blockage Using RELAP5-3D	Crook	TAMU
MYRRHA Primary Heat Exchanger stability analysis	Castelliti	SCK CEN
New Governing Equations for the Realistic Representation of 2 Phase Flow	Roth	University of Idaho
R&D And Experimental Activities at ENEA Connected with the Use Of RELAP5-3D Code	Del Nevo, Agostini, Barone, Coscarelli, Di Piazza, Forgione, Giannetti, D Martelli, E Martelli, Parisi, Balestra, Rozzia, Tarantino, Utili, Venturi	ENEA CR Bransimone ENEU/UNIPISA ENEA/UNIROMA ENEA CR Casaccia ENAU/UNIBO
RELAP5 Applications & Improvements At NuScale	Lucas, Lee	NuScale Power
RELAP5-3D Auxiliary Tools	Forsmann	INL
RELAP5-3D Improvements 2014	Mesina	INL
RELAP5-3D Verification 2014	Mesina	INL
RELAP5-3D Version 4.2.1 Developmental Assessment	Bayless	INL
RELAP-7 Code Development Status Update	Zhang	INL
Selected User Problems and Version 4.2.1 Features	Anderson	INL
Simulation of EBR–II SHRT–17 Test by RELAP5-3D© Code	Del Nevo, Martelli	ENEA CR Brasimone ENEA/UNIROMA
Status of Recent Nodal Kinetics Upgrades in RELAP5-3D	Barber	Information Systems Laboratory
User–Reported Problems September 2013 – August 2014	Anderson	INL
Variable Gravity	Mesina	INL

Idaho Falls 2013 Meeting

International RELAP5 Users Group (IRUG) Seminar and Meeting The 2013 RELAP5 Users Group Meeting was held from September 12-13 2013 in Idaho Falls, ID. There were over to attendees at the meeting and 25 technical presentations. The meeting was preceded by an Introductory RELAP5-3D training class that had over 30 in attendance. The meeting provided a forum for RELAP5 users from around the globe to share their experiences in developing models and performing analyses using the code. In addition, the latter portion of the seminar was set aside for an executive meeting of the International RELAP5 Users Group. Membership in the User Group was not a condition for attendance at the seminar, and technical papers were encouraged based on any version or application of RELAP5. 2013 IRUG Agenda

Name	Authors	Organization
General Approach to Integration of RELAP5 with Other Codes and Remote Web Based Execution	Alessi	INL
Selected RELAP5-3D User Problems	Anderson	INL
RELAP5 Version 4.1.3	Anderson	INL
RELAP5-3D Kinetics Upgrades	Barber	Information Systems Laboratories, Inc.
HTTF Scoping Calculations	Bayless	INL
Comparison of MYRRHA RELAP5 mod 3.3 and RELAP5-3D models on steady state and PLOF transient	Castelliti	SCK-CEN
Evaluation of Variations in the ATR Axial Power Distribution on Core Safety Margins	Davis	INL
Thermal-Hydraulic Analysis Resultsof a Seismically-Induced Loss of Coolant Accident Involving Experiment Out-of-Pile Loop Piping at the Idaho National Laboratory Advanced Test Reactor	Davis	INL
User Tool Upgrades — Pygmalion Status and RGUI Station	Forsmann	INL
Comparison of NRELAP5 to an ORNL THTF Test and the NuScale Critical Heat Flux Tests	Lucas	NuScale Power
NuScale CHF & RELAP5-3D	Lucas	NuScale Power
Architectural Issues and Developments in RELAP5-3D	Mesina	INL
Developer Guidelines for RELAP5-3D Programming, 2013	Mesina	INL
Improvements in RELAP5-3D Plot and Strip Files	Mesina	INL
Verification/Restart/Backup Testing For RELAP5-3D	Mesina	INL
RelapManager-A B&W mPower Safety Analysis Tool	Morgan	Safety Analysis and Methods Engineer
Overview of the RELAP5-3D code activities in ENEA	Parisi, Balestra, Del Nevo, Negrenti	ENEA
Raven as Probabilistic Risk Assessment Tool for RELAP5-3D	Rabiti, Mandelli, Smith,	INL
	Schroeder, Riley,
	St Germain, Alfonsi, Nielsen, Cogliati,
	Kinoshita
Assessment of RELAP5-3D for Future Reactor Designs	Roth, Aydogan	U of I
RELAP5-3D Validation Using HTTF Data	Schultz	VHTR
RELAP5-3D Software Licensing Updates	Smith	INL
Status of the PHISICS/RELAP5-3D Coupling and Application to Phase I of the OECD/NEA MHTGR-350 MW Benchmark	Strydom	INL
Thermal-Hydraulic Research Activity	Vaghetto, Hassan	Texas A&M University
RELAP-7 Code Development Status Update and Future Plan	Zhang	INL
Verification and Validation of a Single-Phase Natural Circulation Loop Model in RELAP5-3D	Zweibaum	NEUP

Sun Valley 2012 Meeting

International RELAP5 Users Group (IRUG) Seminar and Meeting

The 2012 International RELAP5 Users Group (IRUG) Seminar and Meeting was held October 23-24 in Sun Valley, Idaho.

2012 IRUG Agenda

Attendees

Name	Authors	Organization
Advanced Testing	Mesina	INL
AER Dynamic Benchmark Results	Bencik	REZ
Improved Accuracy for Two-Phase Downflow Scenarios	Davis	INL
International Applications of Nuclear Safety Codes	Griffith	INL
Metal Water Reaction Improvements	Anderson	INL
Performance Measures for 4.0.3	Mesina	INL
Recent Applictions of RELAP5-3D at GRNSPG	Lanfredini	University of Pisa
RELAP5-3D Calculations Supporting HTTF Operation	Bayless	INL
RELAP5-3D Code Activities in ENEA	Paris	ENEA
RELAP5-3D Developmental Assessment Update	Bayless	INL
RELAP5-3D Model Improvment	Barber	ISL
RELAP5-3D Participation in CASL	Cebul	INL
RELAP5-3D Software Licensing	Smith	INL
RELAP5-3D Statistics Based Uncertainty Anaylsis	Gertman	Boise State INL
RELAP5-3D-Phisics Coupling Advancements	Epiney Rabiti	INL
Resolution of Flow Direction Depenedence of Critical Flow Models in RELAP5-3D	Buschman	Bettis
Selected Improvements of Opt Level 1 & 2	Mesina	INL
Selected User Problems	Anderson	INL
Verification Testing	Davis	INL
Version Status	Anderson	INL
Window 7 and Pygi Development for Version 4.0.3	Forsmann	INL

Salt Lake City 2011 Meeting

Papers and Presentations from the Salt Lake City Meeting The 2011 RELAP5 International Users Seminar July 26-28, 2011 Salt Lake City, UT. The following list of presentations that were presented at the conference. Click on one of the following titles to view the presentation.

Name	Authors	Organization
CR FB Conv Movie
NOCR FB1 Conv Movie
VHTR CONF Movie
Zweibaum Movie
INSTANT/PHISICS — RELAP5 coupling	A. Epiney, C. Rabiti, Y. Wang, J. Cogliati, T. Grimmett, P. Palmiotti	INL
Beta F90 Version Status	Nolan Anderson	INL
RELAP5-3D Fluid Properties Modifications	Doug Barber, Lance Larsen	Information Systems Laboratories, Inc.
RELAP5-3D Developmental Assessment	Paul D. Bayless	INL
RELAP5-3D Analyses Supporting HTTF Design	Paul D. Bayless	INL
Summer 2011 INL internship project Pygmalion conversion 90/95	Joseph Brooks	INL
RELAP5 and CASL	Peter Cebull	INL
RELAP5 and CASL	Peter Cebull	INL
Multipliers for Single-Phase Heat Transfer Coefficients in RELAP5-3D	Cliff Davis	INL
RELAP5-3D Software Licensing Updates	Gary W. Smith	INL
Hybrid Capsule Assembly for Irradiation Testing	Donna P. Guillen	INL
	Brian Durtschi	INL
	Adam Zabriskie	Utah State University
	Heng Ban
IRUG Member Meeting
RELAP5-3D Architecture and Style	Dr. George L Mesina	INL
RELAP5-3D 2011 Solver Improvements	Dr. George L Mesina	INL
Recent Applications of RELAP5-3D at GRNSPG	N. Muellner	Universita Di Pisa
Using RELAP5 to Analyze Pressure Relief Systems for Noncondensable Gases	Joe Palmer	INL
RELAP5-3D Activities at the ENEA – SIMING Lab	C. Parisi, E. Negrenti, M. Sepielli	[UTFISST-SIMING]
RELAP5-3D Activities at the ENEA – SIMING Lab	A. Del Nevo	[UTIS-TCI]
RELAP5-3D Uncertainty Analysis	A.J. Pawel and Dr. George L. Mesina	INL
Advanced Neutronics: PHISICS project	C. Rabiti, Y. Wang, G. Palmiotti, A. Epiney, A. Alfonsi, H. Hiruta, J. Cogliati, T. Grimmett	INL
VHTR Modeling and Experimental Validation Studies	Richard R. Schultz	INL
Mars Hopper Project	Presented by: R. Schultz	INL
Mars Hopper Project	Work done by: Steven D. Howe, Robert C. O鈥橞rien, William Taitano, Doug Crawford, Nathan Jerred, Spencer Cooley, John Crepeau, Steve Hansen, Andrew Klein, James Werner	INL
Texas A&M RCCS Experimental Facility RELAP5-3D Simulations	Rodolfo Vaghetto, Yassin A. Hassan	Texas A&M University
Introduction to mPower	Jason Williams	Babcock&Wilcox
RELAP5-3D AT THE INL	J. R. WOLF	INL
RELAP5 International Users Group Meeting and Seminar	J. R. WOLF	INL
LWR Sustainability (LWRS) Program Status Uprate	Dr. Hongbin Zhang	INL
A Pilot Framework for Modern Reactor System Analysis Codes	Haihua Zhao	INL
Salt Cooled High Temperature Reactors and Porous Media Flow Modeling in RELAP5-3D	Nicolas Zweibaum, Per F. Peterson	University of California, Be

For additional information please contact: James R. Wolf RELAP5-3D Program Manager Idaho National Laboratory P.O. Box 1625 Idaho Falls, ID 83415-3870 USA Tel:(208)526-7725 Fax:(208)526-0528 Email: [email protected]

West Yellowstone 2010 Meeting

Papers and Presentations from the West Yellowstone Meeting

The 2010 RELAP5 International Users Seminar September 20-23, 2010 West Yellowstone, Montana. The following list of presentations that were presented at the conference. Click on one of the following titles to view the presentation.

For additional information please contact:

James R. Wolf
RELAP5-3D Program Manager
Idaho National Laboratory
P.O. Box 1625
Idaho Falls, ID 83415-3870
USA
Tel: (208)526-7725
Fax: (208)526-0528
Email: [email protected]

Name	Authors	Organization
3D nodalization performances of MASLWR ITF by RELA5-3D v2.4	Cliff Davis	INL
Accuracy Based Generation of Thermodynamic Properties for Light Water in RELAP5-3D	Peter Cebull, Glenn Roth	INL
Air Cooling Analysis of an ATR Fuel Element Using RELAP5 and ABAQUS	Ronaldo Szilard	INL
CASL – The Consortium for Advanced Simulation of Light Water Reactors	Kareem Awny Aly	Babcock & Wilcox Canada Ltd.
Circulating Flow Inside the Bundle of a Vertical Condenser Under Low Flow Rate	Cristhian Galvez, Nicolas Zweibaum, Per Peterson	University of California, Berkeley
Design and Analysis of the PB-AHTR using RELAP5	Ed Harvego, Richard R. Schultz, Ryan Crane	INL
DEVELOPMENT OF A STANDARD FOR V and V OF SOFTWARE USED TO CALCULATE NUCLEAR SYSTEM THERMAL FLUIDS BEHAVIOR	Marek Ben膷铆k, Jan H谩dek	Nuclear Research Institute Rex Plc
DEVELOPMENT OF RELAP5-3D MODEL FOR VVER-440 REACTOR	George L. Mesina	INL
DTSTEP – Development of an Integer Time Step Algorithm
HTTF Analyses Using RELAP5-3D	Paul D. Bayless
Industry Use of Thermal Hydraulic Codes	Robert P. Martin	INL
IRUG Member Meeting
Measurements of Version 3	George L. Mesina	INL
OECD-NRC Benchmark based on NUPEC PWR Subchannel and Bundle Tests (PSBT) – comparisons among RELAP5-3D v2.4.2, RELAP5-Mod3	F. Fiori, A. Petruzzi, A. Kovtonyuk, A. Del Nevo, C. Parisi, F. D—Auria	Universita— Di Pisa
PVM Coupling Junction Component	George L. Mesina	INL
RELAP5 Analyses of a Deep Burn High Temperature Reactor Core	Hongbin Zhang, Michael Pope, Haihua Zhao	INL
RELAP5-3D Flexible Wall Component Fluid Property Improvements	Glen A. Mortensen, Doug Barber, Dan Prelewicz	Information Systems Laboratories (ISL), Inc.
RELAP5-3D Software Licensing Updates	Gary W. Smith	INL
The use of RELAP5 in the structural verification of a Swedish NPP	Thomas Probert
The use of RELAP5 in the structural verification of a Swedish NPP	Thomas Probert
Use of RELAP5-3D at GRNSPG0-UNIPI	C. Parisi, A. Kovtonyuk, C. Matteoli, M. Cherubini, A. Del Nevo, F. D‚Auria	Universita— Di Pisa
Video – 2D_POW_LDLOCA	A. Del Nevo, C. Parisi, F. D—Auria	Universita— Di Pisa
Video – Hot Channel 1D	David L. Aumiller	BMPC
Video – Test Tresca and Deformed
Viscous Stress Terms for the RELAP5-3D Momentum Equations	Adam Kraus and George Mesina	INL
Water Packer Nearly-Implicit Scheme	Rich Riemke	INL

Park City 2009 Meeting

Papers and Presentations from the Idaho Falls Meeting Papers and Presentations from the Park City Meeting The 2009 International RELAP5 Users Seminar was held August 10 – 12th in Park City, Utah. The following is a list of presentations from the conference. Click on one of the following titles to view the presentation. For additional information please contact: Dr. James R. Wolf RELAP5 Program Manager Idaho National Laboratory PO Box 1625 Idaho Falls, ID 83415 Email: [email protected] Phone: (208) 526-7725

Paper Title	Authors	Organization
Summary of features contained in the new Fortran 90 code verstion	Sharpe
RELAP5-3D in Fortran 90	George L.Mesina	INL
3D Reactor Kinetics Upgrades to RELAP5-3D	Doug Barber	ISL
3KEYRELAP5 – Improvements and Applications, Abstract	Igor Arshavsky	WSC
Use and Applications of RELAP5-3D© at the San Piero a Grado Nuclear Research Group of the University of Pisa	Del Nevo	University of Pisa
NGNP Applications of RELAP5-3D	Schultz/Sharpe	NGNP
Viscous Effects in RELAP5-3D	Raymond C. Wang, George L. Mesina	U.C. Berkeley, INL
Natural Convection cooling of the GTL-1 Experiment in the Advanced Test Reactor	Donna Post Guillen	INL
ATR Experience with Attila™ – Update	D. Scott Lucas, Sebastien Frand	INL, CEA
Space Reactors	Lucas
Institutionalize Card 1 Option 3	Rich Riemke	INL
Application of RELAP5-3D to an Innovative Sodium Cooled Reactor	Hongbin Zhang	INL
RELAP5 Comparisons With COMSOL Outcomes for a Simple Hot Spot Evaluation in HFIR, Abstract	LeeTschaepe Dr. Arthur Ruggles
RELAP5-3D Developmental Assessment Results	Paul Bayless Doug Barber	INL ISL
Snap Automated Testing Framework for the RELAP5-3D Developmental Assessment	Doug Barber Paul Bayless	ISL INL
Conservation of Fluid Mass and Energy by RELAP5-3DDuring a SBLOCA Abstract	Cliff B. Davis	INL
Conservation of Fluid Mass and Energy by RELAP5-3DDuring a SBLOCA	Cliff B. Davis	INL
Streamlined Electronic PRocess for Generating RELAP5-3D Input Models Abstract	S. B. Casey	BMPC
Streamlined Electronic PRocess for Generating RELAP5-3D Input Models	S. B. Casey	BMPC
Enlargement of the Assessment Database for Advanced Computer Codes inRelation to the WWER Technology: Benchmark on LB-LOCA Transient in PSB-VVER Facility	A. Del Nevo	UNIPI
Recent RELAP7 Deveopments	Dr. Robert Nourgaliev	INL
RELAP5-3D Licensing and Export Control	Charity Follett	INL

Idaho Falls 2008 Meeting

Papers and Presentations from the Idaho Falls Meeting The 2008 International RELAP5 Users Seminar was held November 18 – 20, 2008 in Idaho Falls, Idaho. The following list of presentations is in the chronological order in which they were presented at the conference. Click on one of the following titles to view the presentation. For additional information please contact: Dr. James R. Wolf RELAP5 Program Manager Idaho National Laboratory PO Box 1625 Idaho Falls, ID 83415 Email: [email protected] Phone: (208) 526-7725

Paper Title	Authors	Organization
Coupled Thermal-hydraulic and Neutronic Model for the Ascó NPP using RELAP5-3D/NESTLE	L. Batet, R. Pericas, E. Morales, F. Reventós	UPC
Towards the development of Thermal-Hydraulic Models aimed at the Auxiliary Systems Design in Nuclear Fusion Technology	L. Batet, L. Sedano, C. Queraltó, E. Mas de les Valls, J.Fradera and F. Reventós	UPC
Three-dimensional Neutron Kinetics/Thermal-Hydraulics VVER1000 Main Steam Line Break Analysis by RELAP5-3D© code	A. Frisani, C. Parisi, A. Del Nevo, F. D’Auria	UNIPI
Outline of the Assessment Activities by RELAP5-3D© performed at University of Pisa: Post-Test Analyses of PKL-III, PSB-VVER AND ROCOM Facilities Experiments	A. Del Nevo, M. Cherubini, A. Spadoni, C. Parisi, F. Moretti, F. D’Auria	UNIPI
Atucha-2 PHWR three dimensional neutron kinetics coupled thermal-hydraulics modelling and analyses by the RELAP5-3D©	C. Parisi, A. Del Nevo, O. Mazzantini, F. D’Auria, K. Ivanov	UNIPI
RELAP5 Analysis of Two-Phase Decompression and Pressure Wave Propagation	Nathan N. Lafferty, Martin L. de Bertodano, Victor H. Ransom	Purdue
A System Analysis Code to Support Risk-Informed Safety Margin Characterization	Nam Dinh, Vince Mousseau and Robert Nourgaliev	INL
Verification and Validation of Corrected Versions of RELAP5 for ATR Reactivity Analyses	Cliff B. Davis	INL
Stratified Flow Phenomena, Graphite Oxidation, and Mitigation Strategies of Air Ingress Accident	Chang Oh	INL
Assessing the RELAP5-3D Conduction Enclosure Model	L. D. McCann	BAPL
INL Experimental Program to Support Validation of CFD Codes	Hugh M. McIlroy Jr	INL
Real Time Models in 3KEYMASTER Simulation Environment	Oussama Ashy	WSC
U.S. LWR Sustainability Program	Ronaldo Szilard	INL
RELAP5 Analysis of Two-Phase Decompression and Rarefaction Wave Propagation under a Temperature Gradient	Nathan Lafferty, Martin Lopez de Bertodano, Victor H. Ransom	Purdue
The Use of RELAP5-3D for Subchannel Analysis of SFR Fuel Assemblies	Matthew J Memmott	MIT
Experimental RELAP5-3D Time Step Improvements	George L. Mesina	INL
RELAP5-3D in Fortran 90	George L. Mesina	INL
Lunar Fission Surface Power Design – Relap5 Point Kinetics	D. S. Lucas	INL
Status of Attila for the Advanced Test Reactor (ATR)	D. S. Lucas	INL
NGNP Methods: Summary of Approach and Plans	Carlos Parisi	INL

Idaho Falls 2007 Meeting

Papers and Presentations from the Idaho Falls Meeting The 2007 International RELAP5 Users Seminar was held November 7-8, in Idaho Falls, Idaho. The following list of presentations is in the chronological order in which they were presented at the conference. Click on one of the following titles to view the presentation. Attendees For additional information please contact: James R. Wolf RELAP5-3D Program Manager Idaho National Laboratory P.O. Box 1625 Idaho Falls, ID 83415-3870 USA Tel:(208)526-7725 Fax:(208)526-0528 Email: [email protected]

Paper Title	Authors	Organization
Welcome & Introduction	Richard R. Schultz	INL
Evaluation of Fluid Conduction and Mixing Within a Subassembly of the Actinide Burner Test Reactor	Cliff B. Davis	INL
Non-Condensable Gas Solubility Modelling	J. Downing and S. Lockley	Rolls-Royce
Experience Using RELAP5-3D for Reduced Enrichment Research and Test Reactor Analysis, the Good and the Not So Good	Floyd E. Dunn	ANL
Progress Report: Fortran 90 Conversion	George L Mesina	INL
RELAP5-3D Versions and Accounting	Nolan Anderson	INL
GAMMA Code for NGNP Air Ingress Analysis	Chang Oh	INL
RELAP5-3D Developmental Assessment Plan	Paul Bayless Doug Barber	INL ISL
SCDAP/RELAP5-3D – A Mechanistic Tool for Severe Accident Analysis	Joy Rempe	INL
Symbolic Nuclear Analysis Package (SNAP)	Glenn Roth	KAPL, Inc.
STREAMLINING OF RELAP5-3D	Dr. George L Mesina Joshua Hykes Riley Cumberland Donna Guillen	INL PSU UMR INL
NGNP Methods: Summary of Approach and Plans	Richard R. Schultz	INL