掺杂Cr_2O_3对UO_2芯块烧结行为的影响  

Effect of Doped Cr_2O_3 on Sintering Behavior of UO_2 Pellet

作　　者：郑新海[1] 魏国良[1] 尹邦跃[1] ZHENG Xinhai;WEI Guoliang;YIN Bangyue(China Institute of Atomic Energy,P.O.Box 275-51,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院反应堆工程技术研究部,北京102413

出　　处：《原子能科学技术》2018年第10期1825-1830,共6页Atomic Energy Science and Technology

摘　　要：提高燃料燃耗的一个有效手段是通过增大UO_2晶粒尺寸来减少元件内部气体压力,在大晶粒UO_2芯块中,裂变气体到达晶界表面的距离增加,因而裂变气体的释放速率降低,元件内部气体压力的增高缓慢。本文研究了添加Cr_2O_3对UO_2晶粒尺寸的影响。对纯UO_2、添加0.5%Cr_2O_3及5%Cr_2O_3 3种配方的芯块进行了试验,在5%H2-Ar保护下,以10℃/min和5℃/min的升温速率升温至1 700℃,然后烧结2h或4h,对比纯UO_2芯块与添加Cr_2O_3的芯块发现,添加Cr_2O_3可有效增大晶粒尺寸;较长的烧结时间可促进晶粒长大;较低的升温速率也使晶粒长大。烧结过程产生液相烧结,液相浸润晶粒边界,促进晶粒长大。A way to increase burnup is to diminish the elements internal pressure by an adequate large grain UO 2 pellet structure.In the large grain size UO 2 pellets,fission gas release rate decreases and the element internal pressure increases slowly.The effects of Cr 2O 3 on grain size of UO 2 pellets were investigated in this work.Pure UO 2,doped 0.5%Cr 2O 3 and doped 5%Cr 2O 3 pellets were studied,in the atmosphere of 5%H 2-Ar,it was going up to 1 700℃at the heating rate of 10℃/min and 5℃/min,then sintered for 2 hours or 4 hours.Results show that the grain size of pellets doped Cr 2O 3 increases compared with pure UO 2 pellets.Lower heating rate and longer sintering time can also promote grain growth.The sintering process produces liquid phase sintering,which infiltrates grain boundaries and promotes grain growth.

关 键 词：燃耗 大晶粒 UO2芯块 CR2O3 液相烧结 

分 类 号：TL352.21[核科学技术—核技术及应用]