中文摘要：

为解决熔盐堆排盐罐中熔盐衰变热稳定导出问题,针对套管型自然循环回路开展了不稳定现象研究实验,对实验中观察到的现象和获得的测量数据进行了分析。实验结果表明,中心管对流体预热作用明显,水箱入口温度较低时流体通过中心管后温升高达40℃;上升段出口液面波动过程中会出现多个波峰,第1个为主峰,其他为附峰;附峰的持续时间一般会长于主峰;水箱入口水温波动频率高于压力等其他参数。不稳定振荡发生时水箱温度均有一定的过冷度。振荡的周期性不明显,流动存在低频振荡的耦合情况。振荡周期与沸腾延迟时间正向最大偏差为71%,负向最大偏差为37%。

英文摘要：

In order to remove decay heat safely from the drain tank,instability research experiment was carried out in thimble tube-type natural circulation loop.The observed phenomena and collected data were analyzed.The results show that the fluid flowing in the center pipe is preheated obviously.Several wave peaks appear when the liquid level goes up and down at the outlet of the heat transfer tube.The first one is called for main peak.Others are called for subordinate peaks.Duration time of subordinate peaks is often longer than that of main peak.Oscillation frequency of temperature at the inlet is higher than those of other parameters.Water in the tank is subcooled when the oscillations occur.The period of oscillation is not obvious.There exists coupling between low frequency oscillations.The positive maximum deviation between the period of oscillation and boiling delay time is 71%,and the negative maximum deviation is 37%.