耐事故燃料控制棒备选材料的燃耗分析

Burnup Analysis of Candidate Materials for Accident Tolerant Fuel Control Rod

为从中子学角度对耐事故燃料控制棒备选材料进行评价,本文将稀土元素的倍半氧化物(Eu_(2)O_(3),Gd_(2)O_(3),Sm_(2)O_(3),Dy_(2)O_(3),Er_(2)O_(3))、Hf及HfO 2等材料的控制棒分别置于相同的全陶瓷微胶囊封装燃料组件中,使控制棒所处组件的累积燃耗达到200 GW·d·t^(-1),采用可执行精细燃耗计算的蒙特卡罗程序RMC,计算了燃耗过程中控制棒价值的变化情况,并与传统的控制棒材料Ag-In-Cd的燃耗行为进行了对比分析。结果表明,Eu_(2)O_(3),Dy_(2)O_(3),Sm_(2)O_(3)和Hf的初始反应性均不低于Ag-In-Cd的反应性,且随着燃耗加深,控制棒价值的衰减相对缓慢,尤其是Eu_(2)O_(3)和Dy_(2)O_(3)的控制棒价值随燃耗加深几乎无衰减,有利于堆芯反应性控制,是优良的控制棒材料。

To evaluate the control rod candidate materials of accident tolerant fuel(ATF)based on neutron physics,the control rods made of the sesquioxides of rare-earth elements(Eu_(2)O_(3),Gd_(2)O_(3),Sm_(2)O_(3),Dy_(2)O_(3),Er_(2)O_(3)),the hafnium(Hf),and HfO_(2) are placed in the same all ceramic microcapsule fuel assembly,respectively,and the cumulative fuel consumption of the assembly in which the control rod is located reached 200 GW·d·t^(-1).The control rod integral worth is calculated during the whole burnup process by using RMC,and the burnup behavior of control rod is compared with that of traditional control rod material Ag-In-Cd.The results show that the initial reactivity of Eu_(2)O_(3),Dy_(2)O_(3),Sm_(2)O_(3) and Hf is not lower than that of Ag-In-Cd,and the worth of control rods decreases slowly with the increase of burnup,especially the worth of control rods of Eu_(2)O_(3) and Dy_(2)O_(3) almost does not decrease with the increase of burnup,which are conducive to the control of core reactivity and are an excellent control rod materials.