The Idaho National Laboratory (INL) is the developer of the RELAP5 thermal hydraulic systems code. Over the last 33 years, the INL has been the primary provider of RELAP5 expertise to the world user community and will continue to do so in the future. It is INL's belief that in order to promote the continued use and development of RELAP5 on a worldwide basis, continuous advancements and improvements must be made in the code's capability. To achieve this advancement, the INL has formed the International RELAP5 Users Group (IRUG). The IRUG is the organization primarily responsible for identifying and carrying out the improvements to RELAP5 that will allow it to maintain its position as the world's foremost reactor safety systems code.
Membership in the IRUG is open to any individual, organization or group that has an interest in using and advancing the RELAP5 code. Our objective is to serve government and industry by providing and maintaining a versatile tool for safety and engineering analyses of nuclear power reactors. The IRUG is structured to provide the best service possible to members and, in general, is structured around member organizations rather than on a country basis. The IRUG is open to governmental organizations, commercial companies, and universities.
The IRUG is focused on use of the RELAP5-3D code. This code is a copyrighted successor to RELAP5/MOD3 and its distribution is controlled solely by the INL through signed license agreements. Key features of this code include 1D, 2D, or 3D hydrodynamics using either Cartesian or cylindrical coordinate systems along with multidimensional neutronics. The Nodal Neutronics Kinetics Module is based on the NESTLE code and contains 1D, 2D, or 3D models. Even though the IRUG's focus is on use of RELAP5-3D, the INL is open to supporting all versions of RELAP5.
Currently RELAP5-3D is configured to operate with the Intel Fortran 9.1 Compiler. Compiler versions will be updated periodically when warranted by compiler maturity.
There are four different levels of membership available in IRUG. Each has a different level of benefits, services, and membership fee as described below. All licensees receive an updated version of the code when a new version is released.
The following fee schedule is effective for all license renewals starting October 1, 2011.
MembersA full member organization is the highest level of participation possible in the IRUG. Members receive the RELAP5-3D code in source form. Multiple copy use is allowed. Two levels of membership are available: Regular and Super User. Regular Member organizations receive up to 80 hours of staff assistance in areas such as model noding, code usage recommendations, debugging, and interpretations of results from INL RELAP5 technical experts. Super Users receive up to 200 hours of staff assistance.
Annual License Fee (Regular User): $25,000 (domestic), $48,000 (foreign)
Annual License Fee (Super User): $56,000 (domestic), $70,000 (foreign)
Multi-use participants are organizations that require use of the code but do not need or desire all the benefits of a full member. Participants receive the RELAP5-3D code in object form. Multiple copy use is allowed. Participants receive up to 20 hours of staff assistance.
Single-Use ParticipantsSingle-use participants are restricted to use RELAP5-3D on a single computer, one user at a time. They receive the RELAP5-3D code in object form and may receive up to 5 hours of staff assistance.
Annual License Fee: $5,600 (domestic), $10,700 (foreign)
University ParticipantsUniversity Participants can acquire a no fee license to RELAP5-3D with the restriction that the code only be used for educational purposes at the university. They receive the code in object form but do not receive any staff assistance.
RELAP5-3D is subject to export controls. Membership in IRUG by non-U.S. citizens or organizations must have prior approval from the United States Department of Energy.
Membership in the International RELAP5 Users Group provides participating organizations access to many INL services that are essential to the successful application of a thermal hydraulic systems code such as RELAP5-3D. These services include:
In addition to the services that organizations receive when they join the IRUG, there are additional optional services that can be performed by INL on a cost recovery basis and include:
Export control restrictions may limit or preclude the use of the code for certain countries, agencies, or companies. However, the commercial use will not extend to providing the code or modified versions to third parties without prior arrangement with the INL.
For technical information, please contact:
Please complete the Technology Deployment Program Participant Data Sheet which will expedite BEAs approval and licensing process.
For licensing information, please contact:
Mr. Gary W. Smith
Sr. Commercialization Manager
Idaho National Laboratory
P.O. Box 1625
Idaho Falls, ID 83415-3870
Phone (208) 526-3780
Questions or problems regarding this web site should be directed to
Last modified: March 30, 2012.