NHR 5负荷自跟随特性与机理的分析

Analysis of Characteristics and Mechanism of Self Load Following in NHR 5

用带有高过冷沸腾模型的ＲＥＴＲＡＮ０２ 程序对５ ＭＷ 核供热堆（ ＮＨＲ５） 负荷增加５０ ％ 和失去全部负荷的自跟随实验进行了分析， 其计算结果与实验结果符合得很好。并对额定工况下负荷增加３０ ％ 和失去全部负荷两种工况的安全性进行了分析， 结果表明反应堆是安全的。同时发现了自然循环冷却的反应堆在负荷变化后， 堆芯流量首先变化， 然后导致堆芯内与流量有关的参数（ 例如空泡份额） 变化， 本文给出了负荷自跟随这类瞬态过程的特征。讨论了空泡的变化规律和控制棒回水温度对自然循环流量的影响。

Via program RETRAN 02 with the model of highly subcooled nucleate boiling,both self load following experiments on the 5MW Nuclear Heating Reactor(NHR 5),load increased by 50%and loss of full load,have been analyzed respectively The results of the experiments and analyses are quite accordant Under rated operation condition,the transients resulted from increase of external load by 30%and loss of full load have also been analyzed,by which the safety of NHR 5 has been verified After load variation,in such a reactor cooled by natural circulation as NHR 5,the flow rate varies first The characteristics of this kind of transients are summarized and a discussion of behavior of highly subcooled void and the influence of the back flow from the control rod system are offered as well