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About RELAP5–3D


International RELAP5
Users Group

RELAP5 Users Seminar 

Code Manuals

Version Releases


User Problems

RELAP5-3D is the latest in the RELAP5 code series developed at the Idaho National Laboratory (INL) for the analysis of transients and accidents in water–cooled nuclear power plants and related systems as well as the analysis of advanced reactor designs.

RELAP5-3D isometric image of the LOFT input model generated with RGUI.

The RELAP5–3D code is an outgrowth of the one-dimensional RELAP5/MOD3 code developed at the INL.  The most prominent attribute that distinguishes RELAP5–3D from its predecessors is the fully integrated, multi-dimensional thermal-hydraulic and kinetic modeling capability.

RELAP5–3D is available from the INL through membership in the International RELAP5 Users Group (IRUG).

The code is currently configured to run on windows 7 using the Intel Fortran Compiler and on Linux using the Intel Fortran Compiler 13.1.3.

RELAP5–3D News

2015 International RELAP5 Training Workshop And Users Group Meeting — Idaho Falls, Idaho USA

This year the INL plans on offering a three–day introductory RELAP5–3D training workshop immediately preceding the Users Group (IRUG) Seminar and Meeting. Dates for the training class are August 10–12, 2015. Please see the attached agenda for training topics covered.

The RELAP–5 International Users Group Meeting and Seminar will be held August 13 – 14, 2015.

Both the Training Workshop and Users Group Meeting will be held in Idaho Falls.

Please follow the link below to the registration and fees website for the Training Workshop information, Call for Papers and Registration instructions.

License/IRUG Membership Fee Increase

Release of RELAP5–3D Version 4.3.3

The INL is pleased to announce that the newest version of RELAP5-3D, identified as RELAP5-3D Version 4.3.3 will be released in early fall of 2015.

For information on how to obtain the code, please contact Mr. Gary Smith at:

Mr. Gary Smith
Sr. Commercialization Manager
Idaho National Laboratory
PO Box 1625
Idaho Falls, ID 83415
Phone: (208) 526-3780

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