【摘要】 为评估西安脉冲堆燃料棒的运行安全性，本文基于MOOSE(multiphysics object-oriented simulation environment)平台，开展了燃料棒的三维热-力耦合分析。通过耦合温度场与位移场，重点研究了不同力学边界条件对燃料棒应力分布的影响。针对特定燃料棒（C10），模拟其在1 a稳态运行后叠加脉冲工况下的响应。模拟结果表明：稳态运行时燃料棒温度分布呈显著的非对称性；脉冲工况下，燃料芯块温度急剧升高，包壳与中心锆棒的温升则存在滞后。力学分析表明，燃料与包壳在稳态运行约3 200 h发生显著接触，间隙压力和体积随之变化，且脉冲工况导致燃料棒整体应力水平升高。研究发现边界约束条件对燃料棒内部应力分布具有决定性影响，采用仅固定底部的约束可显著降低整体应力水平。本文为西安脉冲堆燃料棒的安全评估提供了三维热-力耦合分析依据。更多还原

【Abstract】 To evaluate the operational safety of fuel rods in the Xi’an Pulsed Reactor, a three-dimensional thermo-mechanical coupling characteristics of the fuel rods is analyzed using the multiphysics object-oriented simulation environment(MOOSE) platform. By coupling the temperature field and displacement field, this paper focused on the influence of different mechanical boundary conditions on the stress distribution of the fuel rod. For a specific fuel rod(C10), the response under pulsed conditions after one year of steady-state operation is simulated. The results indicate that during steady-state operation, the temperature distribution of fuel rods exhibits significant asymmetry. Under pulsed conditions, the fuel pellet temperature rises sharply, while the temperature rise of the cladding and the central zirconium rod exhibits a lag. Mechanical analysis shows that fuel-cladding mechanical interaction occurs after approximately 3 200 hours of steady-state operation, leading to changes in gap pressure and volume, and the pulsed condition causes an increase in the overall stress level of the fuel rod. It is also found that boundary constraint conditions have a decisive influence on the internal stress distribution of the fuel rod,and adopting a constraint that fixes only the bottom can significantly reduce the overall stress level. This paper provides a basis for the 3D thermo-mechanical coupling analysis in the safety assessment of Xi’an Pulsed Reactor fuel rods.更多还原