Modeling of Radionuclide Transport for NPP Simulator Using RELAP5 R/T

KEPRI (Korea Electric Power Research Institute) adopted RELAP5 R/T to simulate the NSSS thermal hydraulic phenomena in nuclear power plant (NPP) simulator. The RELAP5 R/T based on a RELAP5 Mod3.2 has an option to perform radionuclide transport within the hydrodynamics. This new version of RELAP5 includes a module to solve transport equation for radionuclide specie which is either radioactive (decays with a half-life) or fertile (absorbs neutrons to create another specie). This paper describes the radionuclide transport model for NPP simulator using RELAP5 R/T. Three major species of the Iodine-131, Xenon-133, and Nitrogen-16 have been modeled. This paper also represents the result of steam generator tube rupture (SGTR) test as the accident could show the characteristics of radiation release