轴向流动液态钠中燃料元件的振动响应分析

Analysis of vibration response of fuel pin induced by liquid sodium in axial flow

在液态钠轴向流动激励下采用经验公式对燃料元件的振动响应进行研究。选取定位绕丝一个步距长的燃料元件作为研究对象,将其简化为由包壳和芯块构成的圆柱体简支梁。通过对经验和半经验公式进行调研分析,选取切实可行的公式并结合工程设计参数对圆柱体简支梁的流动诱发振动进行分析。结果表明,轴向流动液态钠会诱发燃料元件产生振动响应,其中边通道附近的元件尤为显著,但最大振幅偏小,受到的弯曲压力较小,对燃料元件的可靠性和使用寿命影响甚微,满足工程设计的疲劳极限设计需求。

The vibration response of fuel pin under liquid sodium fowling in axial is investigated by empirical expression. The fuel pin with a step length of located wire winding is selected as a model, which is simplified to pined-pined cylinder composed by the cladding and pellet. Based on the investigations of the empirical and semiempirical expressions, the effective and feasible expression is proposed to study the flow-induced vibration of pinedpined cylindrical structure combined with the engineering design parameters. The results show that liquid sodium in axial flow could induce the vibration response of fuel pin, and which is obvious for the fuel pin near the side passageway. Both the amplitude and bending pressure are small. The vibration has little effect on the reliability and service life of the fuel pin. The structure and material parameters satisfy the needs of fatigue limit of engineering design.