The purpose of this study was to design a robust test facility for a small space nuclear power system and model its physical behavior under different scenarios. The test facility will be used to simulate a 1- to 10-kW(electric) nuclear reactor, its electrical generation, and heat removal capabilities. This simulator will be used to explore, test, and understand the steady-state and transient operation capabilities of small space nuclear power systems. Currently, the system is planned to operate on a variable, electrical heat source directly connected to heat pipes. The heat pipes are to be stainless steel with a water working fluid. These heat pipes will then be connected to a power conversion simulator or actual power conversion technologies. The power conversion simulator is connected to a radiator using a water-based heat pipe network using fins and connecting plates in a cylindrical geometry. Modeling of the facility was performed using the SolidWorks Flow Simulation package. Flow Simulation was used to analyze startup, heat pipe failures, and loss of power conversion with the end goal of finding safe operational transient scenarios for the transient test facility.