含MOX燃料组件堆芯顶端注量率峰问题研究

Research on Top Peak Flux Problem of Mixed Core with MOX Fuel

通过详细的建模分析,阐述了顶端注量率峰产生的现象及原因,发现钚铀氧化物混合(MOX)组件顶端热中子注量率峰普遍存在于UO2燃料与MOX燃料的混合堆芯中,针对这一问题,提出了改变MOX组件或UO2组件的顶端组成,在组件顶端加入不同的材料,达到减少中子注量率峰的目的。计算表明,通过在MOX燃料棒顶部加入12～18 cm的Gd2O3毒物的效果最好;采用MOX燃料中心开孔的方式,也能解决这一问题。

Through detailed modeling and analysis, this paper expounds the phenomenon and reason for the top peak flux. It is found that the top peak flux is widespread in the mixed core with MOX fuel. In order to solve this problem, it is proposed to change the top composition of MOX assembly or UO2 assembly to reduce the top neutron flux. Calculations show that adding 12~18 cm Gd2O3 to the top of the MOX fuel rod is the best solution. Center drilling of MOX fuel can also be another solution.