Conceptual design of a novel megawatt portable nuclear power system by supercritical carbon dioxide brayton cycle coupled with heat pipe cooled reactor

Abstract

In order to meet realistic requirements for flexible and reliable power supply in special scenarios such as remote areas and deep ocean exploration, a novel megawatt portable nuclear power system called SUPERHERO (SUPERcritical carbon dioxide cycle-HEat pipe ReactOr power system) is proposed in this paper. The system consists of a heat pipe-cooled reactor and a closed supercritical carbon dioxide (S–CO2) Brayton power cycle. Different cycle concepts were compared, and the simple recuperated cycle was adopted for compactness and simplicity of the system. The multi-objective optimization is performed to maximize cycle efficiency and minimize system volume, resulting in optimized parameters for a 1MWe system. By utilizing uranium nitride (UN) modular fuel elements and high heat transfer capacity potassium heat pipes, a compact reactor scheme with 3.13MWt is determined that can operate for 15 years without refueling. The neutronics and thermal analysis of the reactor are carried out, and the results show that the reactor has safety features such as a low peak factor, negative temperature feedback coefficient, sufficient reactivity compensation and control, and anti-failure of single heat pipe. The primary heat exchanger is also designed using the CFD method, and the heat exchange tubes combined with ribbed plates and self-supporting structures are used to enhance heat transfer and ensure structural stability. All these studies outline the general features of SUPERHERO, demonstrating that SUPERHERO has great development potential.