OPEn HPC theRmomechanical tools for the development of eAtf fuels (OPERA)

由于轻水核反应堆与更多样化的能源组合相结合，在新的运行条件下进一步提高轻水核反应堆的安全性，给燃料开发带来了许多新的挑战。这就需要有效和经过验证的工具，使人们能够捕捉燃料元件在从标称到设计基准事故的各种运行条件下的行为的复杂性。OperaHPC提案的目标是使用高性能计算（HPC）开发开放工具，实现燃料元件的完整3D高保真热机械模拟，包括材料微观结构。这将有助于设计所谓的燃料元件数字双胞胎。这一发展包括一项雄心勃勃的基础研究方案，专门利用从原子尺度到材料定律的多尺度实验和模拟，调查辐照燃料的非线性机械行为。这将产生燃料元件堆内行为的详细描述和模拟所需的材料数据。开发的工具将根据最先进的一维/三维燃料性能代码进行评估，以进行验证，定义边界条件并与中子，热化学和热工水力代码耦合。验证和不确定性分析也将通过3D模拟结果与辐照计划提供的实验数据进行比较。这些先进模拟的知识将转移到工业燃料性能代码，这要归功于基于降阶和Meta模型的新方法的应用，包括人工智能。HPC工具最终将被应用到创新的燃料元件概念的详细评估，包括（增强）事故容限燃料，在瞬态条件下，在几个轻水反应堆设计。

Increasing further the safety of light water nuclear reactors in the new operating conditions induced by their integration in a more varied energy mix brings many new challenges for fuel development. This calls for effective and validated tools enabling one to capture the complexity of the behaviour of fuel elements under various operation conditions from nominal to design basis accident ones.. The objective of the OperaHPC proposal is to develop open tools using High Performance Computing (HPC) enabling a full 3D high-fidelity thermo-mechanical simulation of the fuel element including the material microstructure. This will contribute to the design of so-called fuel element digital twins. This development includes an ambitious basic research program devoted to the investigation of non-linear mechanical behaviour of irradiated fuel using multiscale experiments and simulations from the atomic scale up to the material law. This will yield the detailed description of the in-pile behaviour of the fuel element and the materials data necessary for the simulation. The tools developed will be assessed against state-of-the-art 1D/3D fuel performance codes for verification, definition of boundary conditions and coupling with neutronic, thermochemical and thermohydraulic codes. Validation and uncertainty analyses will also be performed through the comparison of the results of the 3D simulations with the experimental data available from irradiation programs. The knowledge from these advanced simulations will be transferred to industrial fuel performance codes thanks to the application of new methods based on reduced order and meta models, including Artificial Intelligence. The HPC tools will finally be applied to the detailed evaluation of innovative fuel element concepts, including (enhanced) accident tolerant fuels, under transient conditions in several light water reactor designs.