通过实验研究了一体化自然循环反应堆压力壳上部自稳压气空间对于自然循环两相流系统启动过程中流动稳定性的影响。实验结果表明，较小的气空间有利于抑制流量振荡。依此提出在反应堆启动过程中提高流动稳定性的新途径：首先在较小的气空间体积下开始启动，当达到额定热工参数后再将多余的水放出达到所需要的正常运行状态 The effect of the self-regularized gas space above the pressure shell of the integrated natural circulation reactor on the flow stability during the startup of two-phase natural circulation system was experimentally studied. Experimental results show that the smaller gas space is conducive to suppressing flow oscillations. Based on this, a new way to improve the flow stability during reactor start-up is proposed. First, the start-up is started under a small volume of gas space, and when the rated thermal parameter is reached, the excess water is released to reach the required normal operation state