Improvement of computer code DRAGON5 for providing support to safety assessment, criticality studies and core simulation of nuclear reactors

中子确定性模拟基于两个软件组件，一个专用于单元燃料组件，另一个专用于整个堆芯。更复杂的是基于中子玻尔兹曼方程的解和特定模型的晶格编码。它用于临界安全性和反应堆物理应用，通过提供具有多参数数据库的完整堆芯模拟代码。在过去的30年里，École Polytechnique de montral （EPM）开发了晶格代码DRAGON（现在是第5版）和一个名为DONJON的3D扩散代码，用于全核模拟。这两个代码在开源许可下广泛分布在世界各地，并被许多大学和组织使用，他们正在成为DRAGON/DONJON的专家用户。*** Boltzmann方程求解算法的数值性能对DRAGON的精度和cpu效率都有很大的影响。这个NSERC/DG项目的短期目标是研究与现代格码中使用的基本数值技术相关的数学基础、精度和加速问题，以提高DRAGON V5的整体性能。长期目标是向核工业提供软件工具和计算方案，使它们能够评估现有和新型核反应堆的性能和安全特性。前两个子项目重点研究了Boltzmann方程的确定性求解技术：(1)建立了不连续Galerkin格式下的离散坐标（SN）方法；(2)改进了特征法（MOC），发展了一阶代数崩溃法（FOAC）。为了根据DRAGON V5的最新进展开发和验证计算方案，还定义了三个子项目：(3)开发压水堆（压水堆）晶格的两级计算方案，(4)开发ASTRID（工业示范用先进钠技术反应堆）晶格的两级计算方案，(5)开发ASTRID型全芯模拟的微耗尽能力。***与玻尔兹曼方程求解技术的发展或改进有关的科目显然属于博士水平。基于CLE-2000语言的一级和二级计算方案的开发及其与燃烧相关的蒙特卡罗模拟的码对码验证已达到硕士水平。学生。三个硕士。子项目将与工业合作伙伴（如IRSN和GRS）密切合作，以保持我们对生产应用的关注

Neutronics deterministic simulations are based on two software components, one dedicated to the unit fuel assembly and the other dedicated to the full core. The more complex one is the lattice code based on a solution of the Boltzmann equation for neutrons and on specific models. It is used for criticality safety and for reactor physics applications by feeding the full core simulation code with a multi-parameter database. In the last 30 years, École Polytechnique de Montréal (EPM) has developed the lattice code DRAGON, now at Version 5, and a 3D diffusion code named DONJON for full core simulations. These two codes are widely distributed across the world under an open-source license and are used by many universities and organizations who are becoming expert users of DRAGON/DONJON.***The numerical performance of the solution algorithms for the Boltzmann equation has a strong effect on both the accuracy and the CPU-effectiveness of DRAGON. The short-term objective of this NSERC/DG program is to study the mathematical foundations, accuracy and acceleration issues related to the basic numerical technique used in modern lattice code, in a way to improve the overall performances of DRAGON V5. The long-term objective is to provide software tools and computational schemes to the nuclear industry that will enable them to assess the performance and safety characteristics of existing and new types of nuclear reactors. The first two sub-projects focus on deterministic solution techniques of the Boltzmann equation: (1) Development of a discrete ordinates (SN) method with a Discontinuous Galerkin (DG) scheme; (2) Improve the method of characteristics (MOC) and develop the first-order algebraic collapsing (FOAC) method. Three more sub-projects are defined in order to develop and validate computational schemes based on the most recent advances available in DRAGON V5: (3) Development of two-level computational schemes for PWR (pressurized water reactor) lattices, (4) Development of two-level computational schemes for ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration) lattices, (5) Development of micro-depletion capabilities for ASTRID-type full-core simulations.***Subjects related to the development or improvement of solution techniques for the Boltzmann equation are clearly of the Ph.D. level. Development of the one- and two-level computational schemes in CLE-2000 language and their code-to-code validation with respect to burnup-dependent Monte Carlo simulations is of the level of M.Eng. students. The three M.Eng. sub-projects will be investigated in close relationship with industrial partners such as IRSN and GRS, keeping our focus on production applications.**