[en] RELAP5/MOD2 is a pressurized water reactor (PWR) system transient analysis code that has been designed for use in the US Nuclear Regulatory Commission (USNRC) Safety Research and Regulatory Programs. The code is an extension of the RELAP5/MOD1 capability to include simulation of PWR transients up to the point of fuel damage. For analysis of transients involving fuel damage, RELAP5 is being coupled with the SCDAP code, which will permit analysis up to the point of vessel melt through. The improved capability of RELAP5/MOD2 compared to the earlier version is a result of continued improvement of the hydrodynamic models, added user convenience features, and addition of new component models. To a large extent, the new capability has been obtained through logical extension of the RELAP5/MOD1 modeling. As a result, the basic code structure is the same and system model input decks developed for RELAP5/MOD1 are compatible with the RELAP5/MOD2 input requirements, with minor exceptions