RELAP5/MOD2 overview and developmental assessment results from TMI-1 plant transient analysis

RELAP5/MOD2 is a new version of the RELAP5 thermal-hydraulic computer code containing improved modeling features that provide a generic capability for pressurized water reactor transient simulation. Objective of this paper is to provide code users with an overview of the code and to report developmental assessment results obtained from a Three Mile Island Unit One plant transient analysis. The assessment shows that the injection of highly subcooled water into a high-pressure primary coolant system does not cause unphysical results or pose a problem for RELAP5/MOD2.