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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).


RELAP5-3D News

2014 International RELAP5 Users Group (IRUG) Meeting, Training and Seminar - Idaho Falls, ID USA

An advanced RELAP5-3D training class was held on Monday, September 8 through Wednesday September 10, 2014. The training class was followed by the 2014 International RELAP5 Users Group Seminar and Meeting fro Thursday September 11 and Friday September 12, 2014. Please see the meeting presentations for the 2014 meeting under the International RELAP5 Users Group tab.

Release of RELAP5-3D Version 4.2.1

The RELAP5-3D Team is proud to announce the release of the newer version of RELAP5-3D. This version is identified as RELAP5-3D Version 4.2.1 and is available as of June 30, 2014.

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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Last modified: February 6, 2013