Abstract Development of reasonably accurate r educed o rder surrogate m odels (ROM) for infinite dimensional systems is an ongoing line of research. A proper orthogonal decomposition strategy has therefore been resorted in this work to procure a reasonably reliable ROM for the set of coupled thermo-neutronic equations in a small light water reactor. To this end, the pertaining set of PDEs are discretized through a m ethod o f l ines (MOL) approach and a set of f ull o rder m odels (FOM) are obtained for different number of nodes. These models are further reduced applying the POD framework and the resultant low order dynamic systems are compared to the original FOMs in terms of temporal and frequency response behaviors. Results confirm quite acceptable fidelity of the surrogate models in capturing low frequency dynamic features of the original system. At higher frequencies however, ROMs which act as surrogate lumped systems may fail to appropriately reflect the localized perturbations. Simulations are carried out for the core of a small modular power reactor and results are further compared to the common point kinetics formalism.

中文翻译：

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核反应堆动力学的降阶建模

摘要 为无限维系统开发合理精确的降阶替代模型 (ROM) 是一项正在进行的研究。因此，在这项工作中采用了适当的正交分解策略来为小型轻水反应堆中的一组耦合热中子方程获得合理可靠的 ROM。为此，相关的偏微分方程组通过线形法 (MOL) 方法离散化，并为不同数量的节点获得一组完整的模型 (FOM)。应用 POD 框架进一步简化了这些模型，并将由此产生的低阶动态系统在时间和频率响应行为方面与原始 FOM 进行比较。结果证实了替代模型在捕获原始系统的低频动态特征方面的保真度是完全可以接受的。然而，在较高频率下，充当替代集总系统的 ROM 可能无法适当地反映局部扰动。对小型模块化动力反应堆的核心进行了模拟，并将结果与​​公共点动力学形式主义进行了进一步比较。