中文摘要：

在模块化小型反应堆非能动安全系统综合模拟实验装置上进行波动管小破口尺寸失水事故实验,研究波动管小破口失水事故过程中的热工水力现象和非能动安全系统运行特性。模块化小型反应堆发生失水事故后,压力平衡管和安注管线内流体的密度差可以驱动堆芯补水箱（CMT）内的冷流体注入反应堆压力容器,压力平衡管裸露后CMT安注流量出现波动;安注箱（ACC）的安注对事故初期的堆芯冷却效果显著;经自动卸压系统卸压后,内置换料水箱（IRWST）可以对堆芯进行持续稳定的安注和冷却。研究结果表明：波动管小破口失水事故中,非能动安注系统可以对堆芯进行有效注水,并带走堆芯衰变热量。

英文摘要：

The small break loss of coolant accident（SBLOCA） experiment of surge line was performed on the small modular reactor passive safety system test facility, to investigate the thermal hydraulic phenomena and the performance of passive safety system during the accident. In the experiment, the fluid density difference between the pressure balance line and injection line driven the coolant to inject into the Reactor Pressure Vessel（RPV）. When the pressure balance line is no longer submersed, the CMT injection flowrate became unstable; The Accumulator（ACC） had prominent effect on the cooling of the core during the initial period of accident; After the sufficient depressurization of the Automatic Depressurization System（ADS）, the coolant in the In-containment Refueling Water Storage Tank（IRWST） provided sustaining and stable injection and cooling of the core. The experimental results show that the passive safety system can provide effective coolant injection and successful removal of core decay heat under surge line SBLOCA.