Abstract In this work, non-modal stability theory is used to study the non-linear dynamics of the Pressurised Water Reactor (PWR), using a zero-dimensional model. Usually, stability analysis for nuclear reactors is performed using modal methods. Instead, the non-modal approach used in the present work offers a different perspective. This approach considers the so-called short-term behaviour following a disturbance instead of the asymptotic (long-term) one. In the model, point-reactor kinetics with six groups delayed neutrons is used for neutronics, whereas thermal-hydraulics is treated using a two-region model (fuel and coolant). The non-orthogonality of the dynamic matrix of the obtained system shows the possibility of transient energy growth following a disturbance, and the proposed stability analysis offers proof of this. A sensitivity analysis of some parameters is then carried out to study how their variation influences the short-term response of the system. The results of this analysis allow for a ranking of the parameters, allowing the identification of the most significant ones regarding system stability.

中文翻译：

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基于非模态稳定性理论的压水堆堆芯零维模型稳定性分析

摘要 在这项工作中，非模态稳定性理论被用于研究压水反应堆 (PWR) 的非线性动力学，使用零维模型。通常，核反应堆的稳定性分析是使用模态方法进行的。相反，当前工作中使用的非模态方法提供了不同的视角。这种方法考虑了扰动后所谓的短期行为，而不是渐近（长期）行为。在该模型中，具有六组延迟中子的点反应堆动力学用于中子学，而热工液压则使用两区模型（燃料和冷却剂）处理。所获得系统的动态矩阵的非正交性显示出扰动后瞬态能量增长的可能性，所提出的稳定性分析提供了证明。然后对一些参数进行敏感性分析，以研究它们的变化如何影响系统的短期响应。该分析的结果允许对参数进行排序，从而确定关于系统稳定性的最重要参数。