混合能谱超临界水堆堆芯热工-物理性能分析

针对一种新型的超临界水堆设计方案——混合能谱超临界水堆（SCWR-M）进行分析。混合能谱超临界水堆包括热谱区和快谱区两部分，分别布置在堆芯的外部与内部。它在继承了热谱与快谱超临界堆芯设计优点的同时，有效地克服了两者的不足。对于热谱区，冷却剂与慢化剂同向流动，大幅降低了燃料包壳的表面温度和组件的机械加工难度;对于快谱区，采用多层燃料组件和较大的栅距棒径比p/d，可得到较高的燃料转换比和较小的冷却剂负反应性系数。本工作采用自主开发的基于子通道分析和三维物理计算的耦合程序，对混合能谱超临界水堆的热工性能和中子物理性能（包括燃耗性能）进行研究。初步的耦合分析结果表明了混合能谱超临界水堆设计方案的可行性。

Coupled Thermal-Hydraulics and Neutron-Physics Analysis of Supercritical Water Cooled Reactor With Mixed Spectrum Core

Recently, a new supercritical water cooled reactor （SCWR） conceptual design was proposed on the basis of a mixed spectrum core concept consisting of a thermal zone and a fast zone. This new core design was considered to be the hybrid of the existing thermal SCWR and fast SCWR cores. It combines the merits of both thermal and fast SCWR cores, at the same time minimizes their shortcomings. For the thermal zone, the difficulties in the mechanical design and the maximum cladding temperature can be reduced as far as possible by the co-current flow mode; and for the fast zone, a sufficiently large negative coolant void reactivity coefficient and breeding ratio can be achieved by the big value of the ratio p/d and the multi-layer arrangement of fuel rods. The performance, including the burn-up behavior, of the proposed core was investigated with 3-D coupled neutron-physical and thermal-hydraulic calculations. During the coupling procedure, the thermal-hydraulic behavior was analyzed using a sub-channel analysis code and the neutron-physical performance was computed with a 3-D diffusion code. The results obtained so far show that the mixed spectrum SCWR concept (SCWR-M) is feasible and promising.