中文摘要：

基于先进组件程序HELIOS和堆芯节块法程序SIXTUS,研发了超临界水冷堆（SCWR）的中子学计算程序FENNEL-N,并通过与蒙特卡罗程序对比分析了其用于环形燃料超临界水冷堆计算的精度。组件验证结果表明：制作多群数据库的压水堆能谱与超临界水冷堆能谱的差异是导致计算误差的主要原因。堆芯验证结果表明：传统的组件均匀化方法在计算超临界水冷堆时会引入较大误差。应用FENNEL-N程序对组件均匀化方法进行了研究,结果表明,采用优化的组件参数少群结构能减少堆芯能谱变化对精度的影响,采用超组件模型计算组件参数可考虑反射层对组件参数的影响。采用新的组件均匀化方法后,FENNEL-N的计算精度满足了预概念设计需求。

英文摘要：

A neutronics calculation code named FENNEL-N was developed based on the advanced lattice code HELIOS and the core-wise nodal diffusion code SIXTUS.Code accuracy for supercritical water-cooled reactor（SCWR）calculation was validated by comparing with Monte Carlo code.The results of assembly calculation show that the difference between PWR spectrum and SCWR spectrum is the main reason of calculation error.According to core calculations,the traditional assembly homogeneous method will introduce a large error.Studies of assembly homogenization were carried out using FENNEL-N.The results show that the change of spectrum can be taken into account by optimizing the coarse energy group structure,and the effect of reflector on assembly few group constant can be considered by employing super-cell model in assembly calculation.Using new assembly homogeneous method,the results show that FENNEL-N is suitable for SCWR pre-conceptual core design.