简化反应堆一回路系统自然循环的动态比例特性研究

在反应堆安全领域，合适的比例分析对非能动系统实验台架的设计起到了关键作用。为深入了解比例缩放时自然循环瞬态过程的变化机理，基于简化反应堆一回路系统，分别采用H2TS（双向分层比例分析）和DSS（动态比例分析）方法进行了自然循环的比例分析，计算了升降功率工况下的自然循环，对比分析了不同尺度下关键参数的动态变化。结果表明，基于RELAP5的计算结果与实验结果基本一致，5%初始功率以下的阶跃变化不会造成大的流量波动；基于两种比例分析方法所得缩比模型下的计算结果均可基本反映原型参数变化；所有工况下，自然循环流量和冷热段温差在初始阶段05个循环周期内存在较大的波动，之后则相对平稳。

Dynamic Scaling Characteristics on Natural Circulation in Simplified Reactor Primary Loop System

Scaling analysis plays a key role in the design of passive test facilities. To deeply understand the mechanism of transient natural circulation in scaling process, the transient natural circulation based on a simplified reactor primary loop system was investigated with experiments and RELAP5 code. Scaling analysis was performed by means of H2TS method and DSS method, and the dynamic changes on key parameters under power down cases and power up cases were analyzed. The results show that numerical results simulated with RELAP5 code are basically consistent with those experimental ones. Step changes below 5% of the initial power will not cause large flow fluctuation. The calculated results based on the two scaling methods can basically reflect the variation of prototype parameters. Under all cases, the corresponding mass flow rate and temperature difference between the cold and hot section fluctuate greatly within the initial stage of 05 cycles, and then behave relatively stable.