一维开式自然循环系统分析程序的实验验证

基于华龙一号非能动安全壳热量导出系统（PCS）综合性能实验装置实验结果，对采用基于漂移流模型开发的华龙一号PCS程序（PCS?NCCP）进行验证，对比分析了设计工况及非设计工况下PCS?NCCP程序计算值与实验值之间的误差。结果显示，所开发的PCS?NCCP程序能模拟PCS的排热能力、稳态运行特性和动态响应特性，程序计算值能很好地跟踪实验的趋势和幅值变化，绝大部分计算误差落在±20%范围内，验证了PCS?NCCP程序的准确性。

Experimental Validation of Analysis Code for One-dimensional Open Natural Circulation System

To research the thermal hydraulic characteristic of passive containment heat removal system (PCS) of HPR1000, the analysis code for one?dimensional open natural circulation system (PCS?NCCP code) was developed based on drift flow model, which can improve the analysis results compared with the analysis code based on homogeneous flow model. The experimental results of HPR1000 PCS comprehensive performance test facility were adopted in this paper to validate the PCS?NCCP code. The test facility was mainly composed of containment simulator, cooling water tank, natural circulation circuit, steam and gas supply system and data measurement and acquisition system. The operating pressure of the test facility was consistent with that of HPR1000 prototype PCS, and the height ratio is 1∶1. In order to verify the comprehensive performance of PCS, according to the typical thermal hydraulic condition parameters in containment during accidents, HPR1000 research and design team carried out experimental research under several accident conditions, which were divided into designed conditions and non?designed conditions. According to the three?dimensional structure of the test facility, the thermal hydraulic calculation model was established by PCS?NCCP code, and the node sensitivity analysis was carried out. Based on the analysis results, the descending section 1 was divided into 11 nodes and the descending section 2 was divided into 7 nodes; rising section 1 was divided into 19 nodes and rising section 2 was divided into 13 nodes; the heat exchanger was divided into 20 nodes and the water tank was divided into 5 nodes. The node division scheme was then used to calculate the design conditions. The results show that the calculation results for the first design condition are more accurate, the power calculation error is -5?81% and the natural circulation flow rate calculation error is 2?72%. As for the second design condition, the power calculation error is 2?10%, and the natural circulation flow rate calculation error is large, which is 17?99%. Further, 131 steady?state non?designed conditions were calculated. The results show that most of the errors between calculation and experiment are within ±20%, and the conditions with errors of more than ±20% are low?pressure conditions. The possible reason is that when the pressure inside the containment simulator is high, the condensation heat transfer outside the heat exchanger tube is large, so that the system has the ability to maintain a stable flash process near the circuit outlet, so the flow rate of the system is relatively large and the flow is stable. However, when the pressure is low, the relative fraction of non?condensable gas increases, and the condensation heat transfer decreases significantly, resulting in periodic fluctuation of natural circulation flow, and the circuit presents an alternating flow state of two?phase flow and single?phase flow. Thus, the experimental measurement error and calculation error increase. Finally, the PCS?NCCP code was used to calculate a transient condition to validate the transient calculation ability. The results show that the calculated values of natural circulation flow rate and the heat removal power are in good agreement with the experimental values in the overall trend, but there are two obvious flow oscillations in the experimental process, and the code fails to accurately capture this flow instability phenomenon. In the follow?up, the relevant physical models should be further improved to improve the transient simulation ability of the code.