Nuclear power is most suited to satisfy the energy demands of future deep space exploration. In this paper, we propose a static nuclear reactor (the nuclear static thermoelectric reactor [NUSTER]), which offers the advantages of superior modularization, simplification, a fully static state, and passive operation. Based on the conceptual design of a static nuclear reactor, an electrical heating principle prototype was designed and fabricated to validate the feasibility of the fully static passive energy conversion concept. Skutterudite thermoelectric generators (TEGs) were used for static energy conversion, and potassium heat pipes were employed for passive heat transfer. The system start-up performance, restart performance, and thermoelectric performance were investigated using the thermal principle prototype. We proposed a new approach to analyze the heat pipe start-up process based on the heat transfer performance. The experimental results indicated that the restart process can be used to reduce the start-up time, because the low heat flux stage is avoided. During the start-up process, the TEGs hot side heat flux and temperature difference were gradually established, and the TEGs open circuit voltage and power density gradually increased. A maximum open circuit voltage and power density of 38.2 V and 0.92 W/cm(2), respectively, were achieved when the TEGs temperature difference reached 575 degrees C. The high performance of the thermal principle prototype demonstrated the feasibility of the NUSTER conceptual design, and the experimental data can serve as a valuable reference for optimization of static reactor designs.