芯块偏心致周向非均匀传热对SiC燃料棒弯曲特性影响研究  

Investigation on the Influence of Circumferential Non-uniform Heat Transfer Resulted by Eccentricity of Pellets on Bending Characteristics of SiC Fuel Rod

作　　者：卢志威 廖业宏 Lu Zhiwei;Liao Yehong(China Nuclear Power Technology Research Institute,Shen Zhen,Shen zhen 518026,China)

机构地区：[1]中广核研究院有限公司,深圳518026

出　　处：《核安全》2024年第6期69-76,共8页Nuclear Safety

摘　　要：对于采用SiC复合包壳的燃料棒,芯块在包壳内容易偏心,这样会导致燃料棒周向非均匀传热及温度分布,进而产生包壳周向非均匀的热膨胀以及辐照肿胀,最终导致燃料棒弯曲。本文针对上述现象进行了研究,结果表明:芯块偏心会导致SiC包壳在芯块-包壳接触侧的温度高于芯块-包壳分离侧,产生较为显著的周向温度分布不均匀性;在无格架夹持的自由状态下,寿期初SiC包壳向芯块-包壳分离侧弯曲,随着SiC辐照肿胀量的逐渐积累,寿期末向芯块-包壳接触侧弯曲;格架夹持会使SiC包壳的弯曲量显著降低;格架夹持基本不会对SiC包壳的环向应力产生影响,但会使分离侧SiC包壳各层的轴向应力减小,同时使接触侧SiC包壳各层的轴向应力增大。For fuel rods based on silicon carbide composite cladding,the pellet is prone to eccentricity in the cladding,leading to non-uniform heat transfer and temperature distribution around the fuel rod,resulting in nonuniform thermal expansion and radiation swelling around the cladding,ultimately leading to bending of the fuel rod.In this paper,the above phenomena are quantitatively studied.The results show that the eccentricity of pellets leads to higher temperature on the contact side of SiC cladding than on the separation side,resulting in a significant non-uniform circumferential temperature distribution;In the free state,at beginning of life,the SiC cladding bends towards the separation side,and as the SiC irradiation swelling gradually accumulates,it bends towards the contact side at end of life.Grid spacer clamping will significantly reduce the bending amount of SiC cladding;Grid spacer clamping has little effect on the circumferential stress of SiC cladding,but reduce the axial stress of each layer of SiC cladding on the separation side and increase the axial stress of each layer of SiC cladding on the contact side.

关 键 词：SIC 包壳 周向 非均匀 弯曲 

分 类 号：TL33[核科学技术—核技术及应用]