RESEARCH ON THE GENERATION MECHANISM OF BURNOUT JUST UPSTREAM OF THE SPACER SUPPORTING BWR-NUCLEAR ROD BUNDLE

沸水堆核棒束支撑垫片上游烧毁发生机制研究

基本信息

批准号：
10450087
负责人：
FUKANO Tohru
金额：
$ 2.5万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10450087/
关键词：
Nuclear Reactor Nuclear Fuel Rods Spacer Critical Heat Flux Flow Pattern Temperature Fluctuation 過渡変動

项目摘要

A cylindrical flow obstruction which simulates a spacer supporting nuclear fuel rods in BWR was installed in the vertical annular channel. Flow patters, especially the generation of drypatch and burnout, were carefully observed by a high speed video camera. The time variations of temperature on the heating tube surface were simultaneously measured near the spacer at six axially different locations. The results are summarized as follows.(1) Large amplitude temperature change is caused by rapid increase in heat transfer through quite thin liquid film prior to the generation of drypatch which causes the rapid temperature increase due to deterioration of heat transfer.(2) In the case that the liquid was sub cooled at the inlet of the heating test section the temperature difference caused by the occurrence of drypatch was the largest, at most 5℃, when the superficial vapor velocity jG is around 15〜20m/s. Under the condition of jG > 20 m/sit decreased even though the heat flux increased because the annular flow pattern became more fully developed and steady. The generation of drypatch is caused by the drainage in the former case and vaporization of base film liquid.(3) In the case that the void ratio was positive, the flow pattern was slug flow at the inlet and the liquid flow rate was low (jL = 0.1 m/s), the overall flow structure becomes unstable and the maximum temperature attains 140℃ when the drypatch occurred. The area map of the dtypatch generation was proposed.(4) The temperature gradually approached to the final state in the case of sudden change in the heat flux in both cases of increasing and decreasing.(5) In the case of sudden increase in inlet quality temperature gradually changed also, while in its sudden decrease the large and sudden increase in the heating surface temperature. The larger the temperature decrease the easier the occurrence of the burnout.

在垂直环形通道中安装了一个模拟BWR中支撑核燃料杆的隔离杆的圆柱流反对反对。高速摄像机仔细观察到流动模式，尤其是Drypatch和倦怠的产生。在六个轴向不同的位置附近，在垫片附近简单地测量了加热管表面温度的时间变化。结果总结如下。（1）幅度的幅度变化很大，是由于在产生Drypatch之前通过相当薄的液体膜快速增加而引起的，这会导致由于热传递的恶化而导致温度的迅速升高。（2）如果液体在加热测试的入口处被液体差异在温度差的情况下降低。约15-20m/s。在JG> 20 m/SIT的状态下，即使热通量增加，环形流动模式变得更加充分发达和稳定。 Drypatch的产生是由前一种情况下的排水以及基本膜液体的分散引起的。（3）如果空隙比为正，流动模式在入口处sl弹性流动，并且液体流速较低（JL = 0.1 m/s）（JL = 0.1 m/s），总体流量结构不稳定并且最高温度在DRYPATCH发生时最大的温度达到140°时。提出了Dypatch生成的面积图。（4）在热通量突然变化的情况下，在两种情况下，温度逐渐接近最终状态。（5）在入口质量温度突然升高的情况下，同时也会逐渐变化，而在其突然降低并突然降低了加热表面温度的较大升高。温度降低，倦怠的发生越容易。