采用环形燃料的超临界水冷堆核热耦合分析

Coupled Analysis of SCWR With Annular Fuel Assembly

利用三维核热耦合计算程序,设计优化了环形燃料组件,并基于这种组件进行了超临界水冷堆(SCWR)堆芯设计。在环形燃料中,给水从燃料中心及外部流过,可同时对燃料内部及外部冷却。由于这个特性,在相对较高的功率密度情况下也能保证较低的燃料温度及包壳温度。另外,流过燃料中心的水作为慢化剂,可对每个燃料栅元提供足够且均匀的慢化,这对于展平组件局部功率峰是十分有利的。使用DRAGON进行组件优化及不同工况下的截面计算,计算得到的截面形成插值表供堆芯程序使用。堆芯程序采用CITATION及开发的燃耗模块CTBurn进行计算。开发了基于单通道模型的热工程序计算水密度分布,并反馈给中子学计算。计算结果表明,环形燃料用于SCWR可获得较好的中子学性能。

The annular fuel assembly was designed and optimized using three-dimension- al neutronic/thermal-hydraulics coupling code. Based on this assembly, the core design was also carried out. In the annular fuel assembly, the feed water flows through the center hole and periphery of the fuel. This brings both internal and external cooling for the fuel. Because of this character, a low fuel and cladding temperature can be reached with relative high power density. The water in the center hole also provides sufficient and uniform moderation for each pin, which is benefit for the local power distribution. DRAGON was used for assembly calculation to get the macroscopic cross sections. These cross sections were made into interpolated table for core calculation. The core calculation was based on CITATION and auxiliary depletion code CTBurn. The thermal calculation based on single channel model was used to obtain water density distribution. The distribution was taken as feedback for neutronic calculation. The results show that SCWR with the annular fuel assembly is a promising concept.