Cracked nuclear fuel pellets were modelled in the r-θ plane with an azimuthally varying clad surface temperature boundary condition using the PELICAN set of fuel performance models for the commercial finite element software, Abaqus. The temperature boundary condition was assumed to represent heat transfer impairment due to an azimuthally asymmetric carbon deposit on advanced gas-cooled reactor pins. The model predicts the radial and azimuthal displacement of the idealised fuel fragments, together with the resulting elastic, creep and plastic strains in the cladding. These were compared to simulations assuming a uniformly hot or cold boundary condition. Apart from a short period during the return to power from reduced power (70%) operation and outages, the hoop stress in the simulation with an azimuthally varying clad surface temperature was bounded by that of models with a uniform hot or cold surface temperature. The reduced stress was proposed to be due to the greater ability of the fuel fragments to relocate in order to accommodate changes to the power level. As a result, the creep strains in the model with an azimuthally varying clad surface temperature were lower than assuming either a uniform hot or cold boundary condition.

在r-θ中模拟破裂的核燃料芯块使用面向商业有限元软件Abaqus的PELICAN燃料性能模型集，对具有方位角变化的包层表面温度边界条件的飞机进行了分析。假定温度边界条件代表由于先进的气冷反应堆销上的方位角不对称碳沉积而导致的传热障碍。该模型预测理想化燃料碎片的径向和方位角位移，以及在包层中产生的弹性，蠕变和塑性应变。将这些与假设均匀边界条件的模拟进行了比较。除了通过减少电力（70％）的运行和停电恢复供电的短暂时间之外，在模拟的情况下，当包层表面温度沿方位角变化时，环向应力受具有均匀的热或冷表面温度的模型的环向应力所限制。提出减小的应力是由于燃料碎片具有更大的重新定位能力，以适应功率水平的变化。结果，在具有方位角变化的包层表面温度的模型中，蠕变应变低于假定均匀的热边界条件或冷边界条件的蠕变应变。