CORE SIM plus : A flexible diffusion-based solver for neutron noise simulations
CORE SIM plus : A flexible diffusion-based solver for neutron noise simulations
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DOI：
10.1016/j.anucene.2021.108149
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发表时间：
2021-02-18
影响因子：
1.9
通讯作者：
Demaziere, Christophe
中科院分区：
文献类型：
--
作者：
Mylonakis, Antonios;Vinai, Paolo;Demaziere, Christophe
本文介绍了CORE SIM+，基于扩散的中子噪声模拟开发的工具。该模拟器基于频域中的三维双能群中子扩散方程。该工具包括必要的求解器，以计算与系统相关的临界问题，然后对各种扰动的响应，如强度可变的吸收器，随冷却剂流和核心部件振动的扰动。适用于不同类型问题的数值方法已经实现。允许应用非均匀计算网格的能力是可用的，使得可以相对于中子噪声源的特性来优化域的离散化。该模拟器可以通过绿色函数方法以全自动的方式生成核动力反应堆的中子噪声数据库。这些数据库在研究反应堆中的中子噪声响应以及训练用于堆芯监测和诊断的机器学习算法时非常有用。作为验证过程的一部分，CORE SIM+的一个现实的反应堆模型在各种频率下的给定扰动的响应被用来估计相应的点动力学分量，相比一个精确的解析表达式。此外，绿色函数发生器用于计算系统对燃料电池振动的响应。然后将该解与CORE SIM+的直接求解器的解进行比较。作为验证工作的一部分，中子噪声实验与燃料棒的振动进行了模拟，显示出合理的协议与测量。本文介绍了一个具有代表性的压水堆中子噪声数据库。从数据库中选择燃料组件和堆芯筒振动的模拟作为说明性示例，用于演示工具的能力。(C)2021年，任作者。爱思唯尔有限公司出版
The paper presents CORE SIM+, a tool developed for diffusion-based neutron noise simulations. The simulator is based on the 3-dimensional, two-energy group neutron diffusion equation in the frequency domain. The tool includes the necessary solvers to calculate the criticality problems associated with the system and then the response to a variety of perturbations such as absorbers of variable strength, perturbations travelling with the coolant flow and vibrations of core components. Numerical methods suitable for different types of problems have been implemented. A capability that allows to apply non-uniform computational meshes is available so that the discretization of the domain can be optimized with respect to the characteristics of the neutron noise sources. The simulator can generate neutron noise databases for nuclear power reactors via the Green's function method in a fully automated manner. These databases can be useful when studying the neutron noise response in a reactor and when training machine learning algorithms for core monitoring and diagnostics. As part of the verification process, the CORE SIM+ response of a realistic reactor model to a given perturbation at various frequencies is used to estimate the corresponding point-kinetic component, compared to an exact analytical expression. In addition, the Green's function generator is used to calculate the response of a system to a fuel cell vibration. The solution is then compared to the one of the direct solver of CORE SIM+. As part of the validation work, a neutron noise experiment with vibrations of fuel rods is simulated, showing a reasonable agreement with the measurements. A representative neutron noise database generated for a generic pressurized water reactor is described. From the database the simulations of fuel assembly and core barrel vibrations are chosen as illustrative examples for demonstrating the capabilities of the tool. (C) 2021 The Author(s). Published by Elsevier Ltd.