次锕系元素非均相核燃料燃烧演化的热力学行为多尺度模拟

项目名称： 次锕系元素非均相核燃料燃烧演化的热力学行为多尺度模拟

项目编号： No.91226101

项目类型： 重大研究计划

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 丁淑蓉

作者单位： 复旦大学

项目金额： 85万元

中文摘要： 加速器驱动的次临界系统(ADS)是嬗变次锕系元素(MA)的重要途径,含MA的非均相复合燃料是其主要选择。燃料芯块堆内燃烧的热力学行为演化是堆芯安全设计关注的关键问题之一。本研究考虑燃料颗粒和基体的相互作用，根据柱形芯块在堆芯的放置建立其三维的有限元模型，以模拟其细观的温度、结构力学场及 径向的主要变形；在一定的辐照工况下，计算模拟燃料相裂变率和衰变率及基体相的辐照损伤场的演化；建立核燃料晶粒尺度下的惰性气体扩散、肿胀与宏观材料点等效的热力学参数及场量之间的关联；考虑辐照损伤效应建立燃料和基体三维大变形本构关系和应力更新方法；基于更新的拉格朗日方法，建立辐照-热-力耦合的多尺度模拟方法，实现燃料芯块热力学行为的演化模拟；计算文献辐照试验芯块的热力学行为，对比辐照后检验结果，验证模拟方法的有效性，解析其破坏机理。本研究为次临界堆的设计提供理论基础和计算手段，具有科学意义且具重要的工程应用价值。

中文关键词： 复合燃料；嬗变；亚晶化；辐照热力耦和；多尺度模拟

英文摘要： A sub-critical Accelerator Driven System is being considered as an important means to transmute Minor Actinides, and the heterogeneous composite fuels containing MA are regarded as its main candidates. The in-pile thermo-mechanical behaviors evolution of the fuel pellet with increasing burnup is one of the critical issues in the core design. Based on the stacking style of the pellets in the cladding, the three-dimensional finite element models will be developed with considering the interactions between the fuel particles and the matrix, which can simulate both the mesocopic temperature fields, the meso-stress-strain fields and the main macro radial deformation; under certain irradiation conditions, the evolution simulation of the fission rates and decay rates in the nuclear fuel particles together with the irradiation damage fields in the matrix are to be calculated; the multi-scale relationships are to be constructed between the inert gas diffusion and swelling in the grain scale and the effective thermo-mechanical parameters and field variables in the macro material points; the three-dimensional finite strain constitutive relations of the fuel and matrix materials will be deduced with the irradiation damage effects involved; on base of the updated Lagrange Method the computation method of the thermo-mechanical

英文关键词： composite fuel；transmution；recrystallization；irradiation-induced thermo-mechanical coupling；multi-scale simulation