In order to enhance the capability to perform realistic analyses of the core neutronic behavior and the plant system dynamics in respect of accidents with asymmetric core power such as main team line break (MSLB), a three-dimensional reactor kinetics model has been incorporated into a system thermal-hydraulic (T/H) code. In this study, we developed a PARCS core model for coupling with a TRACE 3D T/H model for the reactor vessel and performed a steady-state calculation prior to a MSLB accident for the Advanced Power Reactor-1400 plant.