Basic Study on Regional Oscillation of Nuclear Reactor by Using Coupled Core from a Neutronics

利用中子学耦合堆芯进行核反应堆区域振荡的基础研究

基本信息

批准号：
08458126
负责人：
SHIROYA Seiji
金额：
$ 4.16万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08458126/
关键词：
Regional Oscillation Coupled Core Spatial Coupling Coefficient Neutron Flux Optical Fiber Detector Eigenvale Separation Neutronics Calculation Critical Assembly 出力振動現象大型炉

项目摘要

One can observe a regional oscillation of power in a large sized nuclear reactor. To reveal the mechanism of this phenomenon, a basic study was conducted by using coupled cores constructed in the Kyoto University Critical Assembly (KUCA) of which spatial coupling coefficient was close to that of existing Boiling Water Reactor (BWR).The core separation distance and the fuel pitch in the core were systematically varied to measure the eigenvalue separation (ES) of the spatial first-harmonic mode which is closely related to the reactor stability. The Feynman-alpha, the rod drop and the flux tilt methods were applied to measure the ES values. They were agreed with each other within experimental errors. It was found that the flux tilt method based on the measurement of neutron flux distribution by an optical fiber scintillation detector is powerful to obtain an accurate ES value. Whereas the Feynman-alpha method seems to be difficult to measure ES in strongly coupled core where the first-har … More monic mode is much smaller than the fundamental mode. It was observed that ES becomes larger with decreasing the core separation distance or the fuel pitch.The neutronics calculations were executed to analyze the experimental results on the basis of either diffusion or transport theory. The result of transport calculation agreed better with the experimental result than that of diffusion calculation, since the transport effect was large in the present analysis. For the calculation of the first-mode, although the mesh effect was smaller, the three-dimensional, the energy group collapsing and the transport effects were larger than those for the fundamental-mode. This fact indicates that the larger correction would be necessary in the first-mode calculation compared with the fundamental-mode calculation.Moreover, traials were conducted to apply higher order perturbation theory to calculate the flux tilt and to measure the transmission time of the change in neutron flux from one core to the other core.However, the fruit has not been obtained yet. Less

可以观察到大尺寸核反应堆中电力的区域振荡。为了揭示这种现象的机制，使用在京都大学关键组装（KUCA）中构建的耦合核心进行了基础研究对反应堆的稳定性。应用Feynman-Alpha，杆滴和磁通倾斜方法测量ES值。他们在实验错误中彼此达成共识。已经发现，基于光纤闪烁检测器对中性通量分布的测量的通量倾斜方法具有强大的功能，以获得准确的ES值。尽管Feynman-Alpha方法似乎很难在强耦合的核心中测量ES，而第一束……概括模式更小于基本模式。可以观察到，随着核心分离距离或燃油距离的降低，ES变得更大。进行中性计算以根据扩散或运输理论分析实验结果。运输计算的结果与实验结果一致比扩散计算的结果更好，因为当前分析中的运输效应很大。为了计算第一模式，尽管网格效应较小，但三维，能量组崩溃和传输效应大于基本模式的效果。这一事实表明，与基本模式计算相比，在第一模式计算中需要更大的校正。此外，进行了创伤以应用高阶扰动理论来计算磁通量倾斜度，并测量中子磁芯变化的变化时间，从一个核心到另一个核心，尚未获得水果。较少的