OPEn HPC theRmomechanical tools for the development of eAtf fuels

进一步提高轻水核反应堆在新的运行条件下的安全性，这是因为它们融入了更加多样化的能源组合，给燃料开发带来了许多新的挑战。这就需要有效和有效的工具，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复杂行为。OPERA HPC提案的目标是开发使用高性能计算(HPC)的开放式工具，以实现燃料元件的全3D高保真热机械模拟，包括材料微结构。这将有助于设计所谓的燃料元件数字双胞胎。这一进展包括一项雄心勃勃的基础研究计划，该计划致力于利用从原子尺度到材料定律的多尺度实验和模拟来研究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。开发的工具将对照最先进的1D/3D燃料性能代码进行评估，以进行验证、边界条件的定义以及与中子、热化学和热水力代码的耦合。验证和不确定度分析也将通过将3D模拟的结果与从辐照计划获得的实验数据进行比较来进行。由于基于降阶和元模型的新方法的应用，这些先进模拟的知识将被转移到工业燃料性能代码中，包括人工智能。HPC工具最终将被应用于在几个轻水反应堆设计的瞬变条件下对非创新燃料元件概念的详细评估，包括(增强型)事故容错燃料。

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