中文摘要：

本文研究反应堆碘坑内的启动问题，导出了热堆在碘坑内启动时氙毒反应性、碘和氤浓度随时间变化的解析表达式。通过对所得解析解的计算分析，对碘坑内启动问题有了更全面、本质了解。反应堆停堆前的运行功率、碘坑内启动功率及启动时所处的碘坑内的位置等均将影响到启堆后氙毒反应性的变化规律，所处条件的不同可能导致完全不同的变化规律。另外，碘坑内启堆的时间对反应堆启堆时的安全也是1个重要的影响因素。本文所得结论对提高核动力船只的机动性和安全运行有一定的理论意义和参考价值。

英文摘要：

The reactivity worth of xenon poisoning and the densities of 135X and 135Xe were derived when the reactor was restarted up in iodine pit. Through the expressions obtained we can find the physics characteristics of reactor restarted up in iodine pit comprehensively and essentially. The results were analyzed and discussed. The reactor power before shutdown, the start-up power, the position where the reactor starts up in iodine pit, and so on, all have effect on the reactivity worth of xenon poisoning, and the different conditions can lead to totally different physics characteristics. In addition, the time when the reactor starts up in iodine pit is a very important factor for nuclear reactors safety. The conclusions are very important to the maneuverability and operation safety of ship nuclear reactors.