高温气冷堆是一种具有固有安全性的堆型，合理的热力循环是保证其实现高效率的前提。本项目以高温气冷堆闭式Brayton循环中预冷器和间冷器中排放的低温余热为研究对象，以热力学第一、第二定律为基础，构建用于回收核能闭式Brayton循环低温余热的新型热力学循环，以研究高温气冷堆电厂排放余热的深度利用。研究内容包括：通过构建核能闭式Brayton/ORC联合循环，拓展各种先进热力学循环在核能热力循环中的应用；根据工质的筛选原则，推荐适用于联合循环的有机工质，并探索适用于联合循环混合工质；通过合理调控热力学不可逆性在系统部件间的分布，为实现经济运行和节能降耗奠定理论基础，并建立了综合考虑余热利用效率、投资成本等多准则的系统优化目标，拓展热经济性的应用；通过搭建ORC利用余热的实验测试装置，验证利用ORC回收余热的可能性。本项目对于提高核电厂效率并节约核燃料的消耗，减少热污染，具有非常重要的工程意义。

High temperature gas-cooled reactor is a promising reactor type because of its inherent safety. In order to ensure the high efficiency of power plant, suitable thermodynamic cycle should be adopted. This project aims at the waste heat discharged from the intercooler and precooler in Brayton closed-cycle, and constructs the new thermodynamic cycle to recover and utilize this type of energy based on the first and second laws of thermodynamics. Several steps will be taken to finish this project. Firstly, the Brayton closed-cycle/ORC combined cycle is to be proposed. The organic Rankine cycle (ORC), which is embedded in the Brayton closed-cycle, is used to recover the waste heat rejected by the intercooler and precooler in Brayton closed-cycle. Secondly, according to the screening criteria of the working fluid, such as low toxicity, good material compatibility, fluid stability limits, maximum net power output, maximum thermal efficiency, and maximum exergy efficiency and so on, the working fluids used for the Brayton closed-cycle/ORC combined cycle will be selected. On the basis of the research of the pure organic fluids, the thermal properties of organic mixture will be calculated by using the existing mixing rules and the suitable mixture will be recommended. Thirdly, the optimization objective function, in which the net power output, thermal efficiency, exergy efficiency and investment will be taken into account, will be proposed to achieve the system optimization. Fourthly, an experiment will be conducted to confirm the validity of using ORC for recovering the waste heat. This project is meaningful to increase the efficiency of the nuclear power plant, save the nuclear fuel, and reduce the thermal pollution.