针对细颗粒石墨的改进概率评价方法研究

Modified Probabilistic Assessment Method of Fine-grained Graphite

石墨由于其高中子散射截面和低中子吸收截面特性被广泛应用于第4代高温气冷堆中。由于石墨材料强度分散,与常用的确定论评价方法相比,概率论方法评价其失效更为合适。本文通过有限元软件ABAQUS用户子程序开发了石墨构件失效概率分析模型,采用该模型研究了Hindley模型对细颗粒及国产石墨的适用性,在此基础上提出改进的失效概率计算模型,并通过试验数据加以验证。结果表明,Hindley模型过于保守,改进模型则很好地吻合了试验数据,其结果更为合理,为国产石墨在核反应堆中的应用提供参考依据。

Graphite has high scattering and low absorption cross section of neutron.Therefore,it is widely used in high temperature gas-cooled reactor（HTR）.Because of the variability of strength,the probabilistic method is more appropriate to evaluate the failure of graphite than deterministic method.The failure probability model via subroutines of ABAQUS was developed and the applicability of Hindley model on fine-grained graphite was studied in this paper.A modified model was proposed and verified with test data.The result shows that Hindley model is too conservative and modified model fits data better.This model is more appropriate and can be an important reference to the application of domestic graphite in nuclear power plant.