基于能的梯级利用思路，设计构筑了高温气冷堆与压水堆核　电站相结合的核能联合循环系统流程“超结构”。根据优化目标建立模型，得到２种可供选　用的顶置氦气轮机核能联合循环系统流程方案。经结合实例进行模拟分析，揭示了其热力学　特性，从而提出了核电站联合循环技术更新改造（ＮＲＨＳＣＣ－Ｒｅｐｏｗｅｒｉｎｇ）的途径、方案　及设计分析方法 Based on the concept of “energy-based cascade”, the “superstructure” of nuclear power combined cycle system, which is composed of high temperature gas-cooled reactor and PWR nuclear power station, is designed and constructed. Based on the optimization goal, two kinds of alternative overhead helium turbine nuclear energy combined cycle system flow schemes were obtained. After the simulation analysis with the examples, the thermodynamic characteristics are revealed, and the ways, schemes and design analysis methods of NRHSCC-Repowering are put forward