The RELAP5-3D Newsletter notifies the International RELAP5-3D User community of the latest developments. Brief introductory articles inform readers of recent activities, new developments, and upcoming events regarding the RELAP5-3D code, team, and International RELAP5 Users Group (IRUG).
Editor: Dr. George Mesina
Multi-Unit Dynamic Probabilistic Risk Assessment With RELAP5-3D – D. Mandelli, C. Parisi, A. Alfonsi, D. Maljovec, S. St Germain, R. Boring, S. Ewing, C. Smith, C. Rabiti
An analysis of a multi-unit power plant is performed without the classical Probabilistic Risk Assessment (PRA) tools, but rather, with a fully coupled simulation-based, the Risk Informed Safety Margin Characterization (RISMC) approach.
Twenty-Five Research Publications Involving RELAP5-3D from 2017-2018 – G. Mesina
Some of the many Research and Development publications involving RELAP5-3D from 2017 until April 1, 2018 are listed with bibliographical information and abstracts.
Some Nuclear News Featuring RELAP5-3D from January – G. Mesina
Some January articles showing RELAP5-3D heavily involved in the progress being made in the Nuclear Industry.
First Quarter 2018 RELAP5-3D Announcements – G. Smith and G. Mesina
Updates and changes with the RELAP5-3D code, team, and the International RELAP5 User Group.
The Release date for RELAP5-3D version 4.4.2 has been announced as June 1, 2018.
The User Problem form is available on the RELAP5-3D web site.
The RELAP5-3D Wikipedia page.
Join the RELAP5-3D LinkedIn Group.
Multi-Physics Best Estimate Plus Uncertainty (MP-BEPU) Analysis Framework LOTUS and RELAP5-3D – Hongbin Zhang
This work extends Best Estimate Plus Uncertainty (BEPU) beyond thermal hydraulics to include quantification of uncertainties in calculations that have multiple phenomenological areas.
Timing Study of RELAP5-3D Series 4 Versions – G. L. Mesina
Reports that recent RELAP5-3D code versions run different input models faster or slower for some problems than older versions are examined. Versions studied (Series 4) were released after 2011.
Progress on RELAP5-3D User Problems – Nolan Anderson
Users experience difficulties with RELAP5-3D and submit User Trouble Reports. Some of these are described, along with their resolutions.
The next IRUG (International RELAP5 User Group) Meeting is planned for April 30 - May 4, 2018 at the Residence Inn, 635 West Broadway, Idaho Falls, ID 83402.
The registration URL is:
The IRUG Membership rates will increase in 6 months. See Below.
It will be almost three years since our last License/IRUG Membership rate increase. In order to maintain our high level of service, support, and continued software development such as the release of RELAP5-3D Version 4.4.2, which is expected to take place prior to the 2018 IRUG meeting, a rate increase is needed.
A rate increase of approximately 5% will take effective for license renewals and new agreements executed after June 1, 2018. This increase is needed merely to keep up with inflation. The new rates are being published now to allow you time to include the new rates in your budget requests for next year.
IRUG will continue to provide free RELAP5-3D licenses to domestic and international universities if used for educational purposes only.
All current licensees may renew their existing license prior to June 1. You will then be able to take advantage of the old rate and extend your current license for one year beyond its current expiration date. Please contact our Agreements Administrator, Kaleigh Peterson, at
firstname.lastname@example.org for details regarding your existing license agreement.
If you have any immediate questions regarding the above rate increase, please contact:
Dr. James R. Wolf: 208-526-7725,
email@example.com or Gary w. Smith: 208-526-3780,
RELAP5-3D role in the Risk-Informed External Events Safety Analysis – Carlo Parisi
RELAP5-3D is applied for the risk-informed external events safety analyses performed under the US-DOE LWRS Project, RISMC pathway. RELAP5-3D is part of the external events analysis toolkit.
Critical Heat Flux Update to RELAP5-3D – Y. J. Choi
This article discusses code upgrades to improve the performance of RELAP5-3D when modeling Critical Heat Flux. Report on International RELAP5 User Group (IRUG) membership and on some improvements in the messages for various types of license failure.
IRUG Status and Improved RELAP5-3D Messages – Gary Smith and George Mesina
Report on International RELAP5 User Group (IRUG) membership and on some improvements in the messages for various types of license failure.
RELAP5-3D Publications – Paul Bayless and George Mesina
Journal and Conference articles about or applying RELAP5-3D - listed chronologically.
The next IRUG (International RELAP5 User Group) Meeting is planned for May, 2018.
The IRUG Membership rates will increase in 9 months. See Below.
In July 2017, Glenn Roth received his doctorate from University of Idaho for developing the theory for a 6-field TH model compatible with RELAP5-3D.
INL-internal version RELAP5-3D/Ver. 4.4.1 was released for INL testing in September, 2017. This is considered to be the prequel to the external production code release.
It will be almost three years since our last 'License/IRUG Membership' rate increase. In order to maintain our high level of service, support, and continued software development such as the release of RELAP5-3D Version 4.4.2, which is expected to take place in January 2018, a rate increase is needed. A rate increase will take effective for license renewals and new agreements executed after June 1, 2018. The new rates are being published now to allow you time to include the new rates in next year's budget.
IRUG will continue to provide free RELAP5-3D licenses to universities for educational purposes only. If you have any immediate questions regarding the above rate increase, please contact:
Dr. James R. Wolf: 208-526-7725,
firstname.lastname@example.org or Gary w. Smith: 208-526-3780,
Membership in the International RELAP5 User Group (IRUG) has reached 100 institutions, commercial entities, universities, and other organizations.
The Gateway for Accelerated Innovation in Nuclear (GAIN) initiative epitomizes the new US paradigm for nuclear energy advancement and makes RELAP5–3D available for commercial use.
The resolutions for several recent user problems are described and explained. Three are error fixes and two are code upgrades.
Idaho National Laboratory (INL) and the International RELAP5 Users Group will be offering a five–day Introductory RELAP5–3D Training Workshop from May 1–5, 2017.
A study is performed to determine if RELAP5–3D would perform better (lower mass error) if the fluid properties were calculated in a manner more consistent with the numerical solution scheme.
Development of Pressure, Internal Energy Fluid Properties with Metastable Conditions based on the NIST H2ON and H2O95 Properties.
The resolutions for two legacy and four recent user problems are described and explained.
Membership in IRUG has grown yearly as more and more institutions, commercial entities, universities, and other organizations realize the benefits of membership.
The RELAP5 International Users Seminar brings researchers, developers, analysts, code users and managers together annually to discuss issues, needs, developments and new directions for the nuclear industry and RELAP5–3D.
A study of condensation in the presence of noncondensables at the University of Wisconsin led to improved modeling in RELAP5–3D.
Comparing the RELAP5–3D Jacobian matrix for the TH governing equations to a finite difference numerical approximation of the same Jacobian matrix is providing clues for improving the solution of these fundamentally important equations.
This article summarizes the progress on a task to provide verification of the RELAP5–3D code by comparing it to the RELAP5–3D manuals Volumes I, II, and IV.
The authors present many of the different activities involving the use of RELAP5–3D code currently ongoing at SCK●CEN for modeling MYRRHA, Multi–purpose hYbrid Research Reactor for High–tech Applications.
The October release of the code features many new capabilities, improvements, and error corrections both in RELAP5–3D and in some of its auxiliary programs.
Improvements to the code’s multi–deck input capability correct errors and increase its applicability. This has created the new capability to run a sequence of restart calculations from a single file which has proven useful for parameter studies.
The auxiliary program that couples RELAP5–3D and other programs to model complex problems through domain decomposition, PVMEXEC, is being updated and upgraded to R5EXEC.
Beginning on October 1, 2015, rates have increased for all license renewals and new agreements.
This quarter's lead article presents a RISMC, Risk-Informed Safety Margin Characterization, algorithm, its implementation by combining RELAP5–3D with RAVEN, and an example.
The second article presents a high-level summary of the p-h interpolator that allows users access to the RELAP5–3D thermodynamic property table data with pressure and enthalpy as the independent variables.
In the third article, corrections to user problems and expansion of capabilities are presented.
The final article announces an IRUG membership fee increase and a way to postpone it for your organization.
Calendar year 2014 was a good one for the IRUG community. A record number of license agreements are currently in effect, 82, with an apparent increase of users within each licensee's organization. Increased IRUG membership benefits all users since a fixed percentage of license fees is reinvested in code development and enhancements. For the second year in a row, RELAP5-3D training was offered prior to our annual "International IRUG Users Seminar." Based upon its popularity, this training will be offered again in 2015. New license options that will focus on lowering costs over the long run are being planned. Details will be announced in the April Newsletter.
This quarter's lead article presents problems resulting from introduction of FORTRAN 90+ data management capabilities, rules to prevent the issues, and a project to systematically modify the existing code to enforce the rules.
The second article presents a renewed code capability, molecular diffusion. It was not originally converted to FORTRAN 90, but has now been renovated and restored.
This quarter's lead article summarizes the growth of the International RELAP5 Users Seminar, covers the proposed fee increase, extends memberships to 5 years, and explains restrictions on RELAP5-3D access by foreigners.
The second article presents high-level information on code issues discovered and corrected by using the verification suite. All known restart and backup issues have been resolved and new code capabilities are now being tested.
This quarter's lead article announces the International RELAP5 Users Seminar on Sep. 8-12 with advanced RELAP5 training, call for papers, timetable of deadlines, and local attractions and activities for individuals and families.
The second article presents detailed information about features, error corrections, and other developments for RELAP5-3D Version 4.2.1
The final article of the second quarter discusses the verification capability and two new ways it has been improved since created and released last year.
This quarter's lead article announces an initiative to create an issue of an American Nuclear Society journal dedicated to RELAP5-3D. Many authors have promised to write papers and these are listed in the article.
The second article presents RELAP5-3D User Problems that have been solved in the first quarter of the year.
This quarter's lead article features information about an automated kinetics time step independent of the thermal hydraulics time step has been implemented to allow improved performance.
The second article presents RELAP5-3D issues involving a requirement for left-to-right evaluation of Fortran if-clauses. This causes RELAP5-3D runtime errors on platforms that do not force this order. The issue has been resolved.
This quarter's lead article features information about Out International RELAP5 User Group including membership growth and a breakdown of the categories of membership.
The second article discusses performing deletion calculations with RELAP5-3D coupled with PHISICS. Results of a sample calculation are presented.
The third article presents a brand new capability available in version 4.1.3 that allows a developer to apply sequential verification of the code through a highly accurate comparison capability.
The Second RELAP5-3D Quarterly Newsletter of 2013 is organized into two parts: Applications and Development News.
The Quarter's lead article features information about Small Modular Reactors and how RELAP5-3D is being used to model and prepare them. The coupling between RELAP5-3D and STAR–CCM+ can be used to model SMRs, NGNP, and many other applications. The Consortium for Advanced Simulation of Light Water Reactors has integrated RELAP5-3D into VERA, the Virtual Environment for Reactor Applications.
In Development News there are two articles. First is the Announcement of the pending release of RELAP5-3D Version 4.1.3. Also, Developer Guidelines for programming RELAP5-3D have been released outside the INL for the first time; this comes at the request of clients who are modifying the code.
This is the RELAP5-3D Quarterly Newsletter for the months of January - March, 2013. Discuss the challenge the differnt time scales involved in coupling depletion thermo hydraulic simulation. Learn more about the RELAP-3D station and the plant model. What do you need to know about the order of evaluations for RELAP-3D? Find out about the capabilities of modeling in moving environments. Discover the limiting areas in your model so you can optimize for execution results.
This is the RELAP5-3D Quarterly Newsletter for the months of October - December, 2012. Discover information on the success of the transient analysis coupling of PHISICS within RELAP5-3D. Uncover resolutions to reported user problems. Want to create a new input file with updated initial conditions in RELAP5-3D? There's a newly updated Pygi to support that. Kinetics received a new redesign. The new memory structure now relies on allocatedable arrays and pointers.
This is the RELAP5-3D Quarterly Newsletter for the months of July - December, 2012. This newsletter informs readers about recent activities, new developments, and upcoming events regarding the RELAP5-3D code, team, and International RELAP5 Users Group (IRUG).
The first issue, for January – March 2012, presents a baseline for the team and code. The team members and their roles are presented in the first article. Since justification of the switch from version 2.4 to Beta version 3.0 is necessary for many code users, the second article presents the recent Developmental Assessment (DA) of version 2.4; the DA of version 3.0 Beta will be presented in an article after the code release. Also listed are recent code developments and other information about the code, the team, and IRUG.
Subsequent issues will contain more information than this inaugural issue. However, it is hoped that this initial information will be useful to the reader.