Verification and Uncertainty Evaluation of LOCUST Reflood Model
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摘要: 再淹没阶段是压水堆发生大破口失水事故(LBLOCA)后的重要阶段,为了评估系统软件LOCUST对该阶段的模拟能力,开展了LOCUST软件再淹没模型验证与不确定性研究工作。基于RBHT实验台架实验结果对LOCUST软件再淹没模型进行了验证;同时采用响应曲面法对再淹没模型开展了不确定性分析,将壁面-液膜沸腾换热系数、壁面-汽膜沸腾换热系数和界面摩擦系数作为输入参数,采用响应曲面法获得了RBHT实验台架实验段3个高度下加热棒表面最高温度的响应函数。验证计算结果与实验结果总体趋势符合良好,最高温度偏差在40 K以内。基于响应曲面法计算结果可知,95%的概率和95%的置信度下加热棒表面3个高度的最高温度最大偏差在20 K左右;当3个输入参数无量纲因子分别为1.951、1.233、0.1条件下,3个高度的最高温度计算值与实验值基本一致。Abstract: The reflood stage is an important stage after a large break loss of coolant accident (LBLOCA) in pressurized water reactor. In order to evaluate the simulation ability of the system code LOCUST, the verification and uncertainty research of LOCUST reflood model are carried out. Based on the experimental results of RBHT test bench, the LOCUST reflood model is verified. At the same time, the uncertainty of the reflood model is analyzed by response surface method, and the response function of the maximum temperature of the heating rod surface at three heights of RBHT test section is obtained by response surface method with the wall-liquid film boiling heat transfer coefficient, wall-vapor film boiling heat transfer coefficient and interface friction coefficient as input parameters. The calculated results are in good agreement with the experimental results, and the maximum temperature deviation is within 40 K. Based on the calculation results of response surface method, the maximum deviation of the maximum temperature of the heating rod surface at three heights is about 20 K with 95% probability and 95% confidence. Meanwhile, the highest temperature values calculated for the three heights are basically consistent with the experimental values when the dimensionless factors of the three input parameters are 1.951, 1.233, and 0.1, respectively.
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Key words:
- Reflood /
- LOCUST /
- RBHT /
- Uncertainty
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图 1 RBHT实验台架实验段[10]
Figure 1. Test Section of RBHT Facility
图 2 RBHT加热棒束截面视图[10]
Figure 2. Cross Section View of RBHT Heating Rod Bundle
表 1 注入流量与功率变化
Table 1. Variation of Injection Flow and Power
时间/s 注入流量/(kg·s−1) 功率/W 0 0 0 0.5 0.06 71919 1 0.125 143838 1062 0.125 143838 1062.5 0.06 71919 1063 0 0 表 2 不同轴向高度处加热棒表面最高温度实验结果与LOCUST计算结果对比
Table 2. Comparison of Maximum Heating Rod Surface Temperature at Different Axial Heights between Experimental Data and LOCUST Calculation Results
z/m 加热棒表面最高温度/K 偏差/K 计算值 实验值 1.40 874.48 901.70 27.22 2.37 1025.93 1061.30 35.37 2.93 1024.25 1032.40 8.15 表 3 不同轴向高度处骤冷时间实验结果与LOCUST结果对比
Table 3. Comparison of Quench Time at Different Axial Heights between Experimental Data and LOCUST Results
z/m 骤冷时间/s 偏差/s 计算值 实验值 1.40 280 311.5 31.5 2.37 644 695.2 41.2 2.93 1010 925.8 84.2 表 4 不同轴向高度处加热棒表面最高温度实验结果与RSM结果对比
Table 4. Comparison of Maximum Heating Rod Surface Temperature at Different Axial Heights between Experimental Data and RSM Results
z/m 加热棒表面最高温度/K 温度偏差/K RSM LOCUST 1.40 874.48 874.48 0 2.37 1027.03 1025.93 1.1 2.93 1028.90 1024.25 4.65 -
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