Correction of microstructural aberrations in Neutron Diffraction strain measurements in power plant structures

残余应力表征是结构完整性评估的一个重要方面。利用中子衍射技术进行残余应力表征是非常理想的，然而，核电厂部件中存在的复杂结构使该过程充满了误差。在这里，提议的项目将使用蒙特卡罗射线追踪模拟中子衍射技术来预测由电厂部件中存在的典型微观结构特征（如焊缝和包层）引起的误差。模型将使用McStas射线追踪代码构建，并使用在中子衍射设备上进行的测量进行验证。这将最终验证由EBSD驱动的模拟能力或实际组件的断层扫描数据，以纠正中子衍射技术产生的残余应力图。减少残余应力数据的不确定性是改进安全评估的关键基石。

Residual stress characterisation is an essential aspect of structural integrity assesment. Conducting residual stress characterisation using the Neutron diffraction technique is very desirable, however, the complex structures present in nuclear power plant components make this process fraught with errors. Here the proposed project will use Monte Carlo ray tracing simulations of the neutron diffraction technique to predict the errors induced by typical microstructural features present in power plant components, such as welds and cladding. Models will be constructed using the McStas ray tracing code and validated using measurements made at neutron diffraction facilities. This will culminate in validated simulation capabilities driven by EBSD or tomography data of actual components to correct residual stress maps produced by the neutron diffraction techniques. Reducing the uncertainty of residual stress data is a key stepping stone in improving safety assessments.