Abstract In an attempt to explore the significance of transport theory in neutron noise, localization of a noise source by Green’s function based on transport theory is investigated. There are considerable differences between Green’s functions based on diffusion and transport, such as small dimensions, near edges, high heterogeneity medium and high-frequency source of perturbation. These differences are expected to significantly impact unfolding, reconstruction, and identification of the neutron noise source. Improvement in noise source unfolding methods is essential in terms of safety aspects and reactor performance enhancement. Since gaining the ability to monitor nuclear reactor based on noise diagnostics principle using few numbers of detectors is a challenging problem, more accurate methods of calculation of neutron noise can help reduce the detectors in number and sensitivity to location. This study revealed that inverse Green’s function based on diffusion and transport is fundamentally different in concept. The inverse Green’s function based on diffusion theory requires applying complicated reconstruction methods to gain more accurate results. This means that a large number of detectors must be used for noise source reconstruction. In contrast, in the case of inverse Green’s function based on transport theory, each mesh's shape function is strongly correlated with the adjacent mesh. As a result, simple methods can be used to reconstruct the noise source. Therefore, the noise source can be identified and reconstructed with a smaller number of detectors in practical terms.

中文翻译：

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基于输运理论的中子噪声源精确定位与扩散理论对比

摘要 为了探讨输运理论在中子噪声中的意义，研究了基于输运理论的格林函数对噪声源的定位。基于扩散和传输的格林函数之间存在相当大的差异，例如小维度、近边缘、高异质性介质和高频扰动源。预计这些差异将对中子噪声源的展开、重建和识别产生重大影响。在安全方面和反应堆性能增强方面，改进噪声源展开方法是必不可少的。由于使用少量探测器获得基于噪声诊断原理监测核反应堆的能力是一个具有挑战性的问题，更准确的中子噪声计算方法有助于减少探测器的数量和对位置的敏感度。这项研究表明，基于扩散和传输的逆格林函数在概念上有着根本的不同。基于扩散理论的逆格林函数需要应用复杂的重建方法以获得更准确的结果。这意味着必须使用大量检测器进行噪声源重建。相比之下，在基于输运理论的逆格林函数的情况下，每个网格的形状函数与相邻的网格有很强的相关性。因此，可以使用简单的方法来重建噪声源。因此，实际上可以用较少数量的检测器来识别和重建噪声源。