Modelling explicit fracture of nuclear fuel pellets using peridynamics
Modelling explicit fracture of nuclear fuel pellets using peridynamics
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DOI：
10.1016/j.jnucmat.2015.08.037
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发表时间：
2015-12
影响因子：
3.1
通讯作者：
R. Mella;M. Wenman
中科院分区：
文献类型：
--
作者：
R. Mella;M. Wenman
本文采用非局部无网格断裂力学方法--周向断裂力学，研究了不同功率下核燃料芯块的三维显式开裂模型。这些模型在明确集成的分子动力学代码LAMMPS中实现，该代码被修改为包括固体中的热应变。在初始功率瞬变过程中，燃料断裂的模型与在芯块的内边缘和外边缘上观察到的裂纹的平均数量相关，通过对燃料的实验性辐照后检查，功率额定值为10和15 W g− 1UO 2。颗粒模型显示出预测预期特征的能力，例如中等高度颗粒裂纹、径向裂纹的正确数量以及径向裂纹的起始和合并。这项工作提出了一个替代的建模经验断裂数据中发现的许多燃料性能代码，只需要一个参数的断裂应变。裂纹数的威布尔分布拟合的数值和实验数据，使用最大似然估计，以便统计比较。研究结果表明，P值小于0.5%，表明模型和实验分布之间的良好协议。
Three dimensional models of explicit cracking of nuclear fuel pellets for a variety of power ratings have been explored with peridynamics, a non-local, mesh free, fracture mechanics method. These models were implemented in the explicitly integrated molecular dynamics code LAMMPS, which was modified to include thermal strains in solid bodies. The models of fuel fracture, during initial power transients, are shown to correlate with the mean number of cracks observed on the inner and outer edges of the pellet, by experimental post irradiation examination of fuel, for power ratings of 10 and 15 W g−1UO2. The models of the pellet show the ability to predict expected features such as the mid-height pellet crack, the correct number of radial cracks and initiation and coalescence of radial cracks. This work presents a modelling alternative to empirical fracture data found in many fuel performance codes and requires just one parameter of fracture strain. Weibull distributions of crack numbers were fitted to both numerical and experimental data using maximum likelihood estimation so that statistical comparison could be made. The findings show P-values of less than 0.5% suggesting an excellent agreement between model and experimental distributions.