Control of xenon spatial oscillations of nuclear reactors during load follow operations

负载跟踪操作期间核反应堆氙空间振荡的控制

• 批准号: 02650199
• 负责人: IWAZUMI Tetsuo
• 金额: $ 1.34万
• 依托单位: Nagoya Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02650199/
• 关键词: Nuclear Reactors; Load Follow Operations; Xenon Spatial Oscillations; Neutron Flux Distribution; Distributed Parameter Systems; Robust Servo Systems; Computer Code; Axial Offset; 沸騰水型原子炉; ロバストサ-ボ系; 計算機コ-ド; 加圧水型原子炉

In near future, the problem of spatial oscillations of the neutron flux distribution from xenon poisoning is one of important problems arisen from load follow operations in nuclear power generations. In this investigation, for the spatial control problem in distributed reactors we obtained the following results from the different two points of view. (1)The spatial control problem of the neutron flux distribution is treated as the design problem of robust servo systems for a distributed reactor. After suitable mathematical models are described for both pressurized water reactor(PWR) and boiling water reactor(BWR), the finite dimensional model to design the control systems are derived using the Galerkin approximate method and the singular perturbation method. In order to achieve the control purpose the total thermal power and the axial offset are chosen as outputs to be controlled. Applying the design method of robust servo systems for this model the feedback control law are found, which achieves to follow up load changes with maintaining the distribution shape of neutron flux. It is noted that the control systems are designed based on the lower dimensional model avoiding the control/observation spillover. These theoretical results are confirmed by some numerical simulations. It is particularly shown that the designed servo systems are robust against model errors due to linearization and modal truncation. (2)The computer simulation codes are developed for BWR to analyze and evaluate effects of the control strategy for neutron flux distributions. The two-group diffusion model with reflectors are adopted to exactly analyze the distributions of states in the reactor core. The steady state solutions are calculated by using the finite difference method based on flux distribution and heat transfer modules. Then the transient responses of states in core are analyzed by using the Crank-Nicolson method.

在不久的将来，来自Xenon中毒的中子通量分布的空间振荡问题是核电后代的负载操作引起的重要问题之一。在这项研究中，对于分布式反应堆中的空间控制问题，我们从不同的两个观点获得了以下结果。 （1）中子通量分布的空间控制问题被视为分布式反应器的稳健伺服系统的设计问题。描述了适当的数学模型为加压水反应堆（PWR）和沸水反应堆（BWR）介绍后，使用Galerkin近似方法和奇异扰动方法得出了设计控制系统的有限尺寸模型。为了实现控制目的，选择总热力和轴向偏移作为要控制的输出。在此模型中应用强大伺服系统的设计方法找到了反馈控制定律，该方法可以跟踪负载变化，并维持中子通量的分布形状。注意到，控制系统是基于较低维模型设计的，避免了控制/观察溢出。这些理论结果通过一些数值模拟证实。特别表明，由于线性化和模态截断，设计的伺服系统对模型误差具有鲁棒性。 （2）为BWR开发了计算机仿真代码，以分析和评估控制策略对中子通量分布的影响。采用带反射器的两组扩散模型来精确分析反应器核心中状态的分布。稳态溶液是通过使用基于通量分布和传热模块的有限差方法来计算的。然后，使用曲柄 - 尼科尔森方法分析了核心中状态的瞬态响应。