Abstract We developed a SPH equivalence technique in non-fundamental mode condition between a full-core model solved with the method of characteristics (MOC) in 2D and a simplified full-core diffusion model with two-group, finite-difference method over a pure Cartesian mesh. The MOC and diffusion calculations are performed with DRAGON5 and DONJON5 codes, respectively. An objective function is set as the root mean square (RMS) error (MOC-diffusion discrepancy) on absorption distribution and leakage rates defined over the macro-geometry in DONJON5. Three algorithms were developed to converge on the SPH factors in non-fundamental mode condition: a fixed point method, a pure Newton method for unconstrained optimization and a memory-limited Broyden-Fletcher-Goldfarb-Shanno (LBFGS) method. We investigated the benefit of all these three techniques on a series of LEU-COMP-THERM-008 BAW Core-XI loadings. We observe convergence success for all numerical techniques considered in this study.

中文翻译：

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非基本模式案例中 SPH 等效技术的一般介绍

摘要 我们在非基模条件下开发了一种 SPH 等效技术，用于在使用 2D 特征法 (MOC) 求解的全核模型和使用纯的两组有限差分方法求解的简化全核扩散模型之间进行 SPH 等效技术。笛卡尔网格。MOC 和扩散计算分别使用 DRAGON5 和 DONJON5 代码执行。目标函数被设置为 DONJON5 中宏观几何上定义的吸收分布和泄漏率的均方根 (RMS) 误差（MOC 扩散差异）。开发了三种算法来收敛非基本模式条件下的 SPH 因子：定点方法、用于无约束优化的纯牛顿方法和内存受限的 Broyden-Fletcher-Goldfarb-Shanno (LBFGS) 方法。我们研究了所有这三种技术对一系列 LEU-COMP-THERM-008 BAW Core-XI 加载的好处。我们观察到本研究中考虑的所有数值技术的收敛成功。