Uncertainty Quantitative Analysis of Subchannel Code Calculation of PSBT Void Distribution Benchmark

doi:10.16183/j.cnki.jsjtu.2021.068

Abstract

Abstract:

In order to evaluate the accuracy and reliability of the subchannel code, it is necessary to quantitatively give the uncertainty of the calculation results. The uncertainty analysis is conducted by using the statistical method based on propagation of input uncertainties, and the uncertainty range of the subchannel code calculation results can be obtained quantitatively. Based on the assumption that the uncertainty of model parameters obeys normal distribution, the statistical method is used to determine the distribution of the uncertainty of model parameters to replace the traditional expert judgment. Through the calculation of the pressurized water reactor sub-channel and bundle tests (PSBT) benchmark, the ability of the subchannel code COBRA-IV to predict the experimental results is analyzed, and the uncertainty interval satisfying the tolerance limit of the calculation results is obtained. The results demonstrate that the experiment data is well enveloped by the obtained uncertainty bands and the model calibrated by the statistical mean value presents a good improvement of calculations.

Key words: uncertainty quantification, subchannel code, void fraction

CLC Number:

TL334

ZHANG Juntao, LIU Xiaojing, ZHANG Tengfei, CHAI Xiang. Uncertainty Quantitative Analysis of Subchannel Code Calculation of PSBT Void Distribution Benchmark[J]. Journal of Shanghai Jiao Tong University, 2022, 56(10): 1420-1426.

Figures/Tables 9

Fig.1

Tab.1

Comparison of evaluated parameters and real values

参数	真实值	计算值	相对误差绝对值/%
$μ x 1$	-0.6	-0.647 8	7.96
$σ x 1$	0.3	0.281 7	6.23
$μ x 2$	1.2	1.137 1	5.24
$σ x 2$	0.2	0.221 3	10.65

Tab.1

Fig.2

Tab.2

Fig.3

Tab.3

Fig.4

Fig.5

Fig.6

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参数	取值
组件	B5(图示①)	B6(图示②)	B7(图示③)
棒束排列	5×5	5×5	5×5
加热棒数	25	25	24
套管数	0	0	1
加热棒外径/mm	9.50	9.50	9.50
套管外径/mm	-	-	12.24
加热棒间距/mm	12.60	12.60	12.60
轴向加热长度/mm	3 658	3 658	3 658
流道内宽度/mm	64.9	64.9	64.9
径向功率分布类型	A	A	B
轴向功率分布类型	均匀	余弦	余弦
搅混叶片格架数	7	7	7
非搅混叶片格架数	2	2	2
简单格架数	8	8	8
搅混叶片格架位置/mm	471, 925, 1 378, 1 832, 2 285, 2 739, 3 247
非搅混叶片格架位置/mm	2.5, 3 755
简单格架数位置/mm	237, 698, 1 151, 1 605, 2 059, 2 512, 2 993, 3 501

模型或参数	内容
过冷空泡份额模型	Levy模型
空泡份额模型	滑移模型
两相摩擦倍增因子	Armand模型
湍流交混模型	EM模型
两相湍流交混倍增因子	Beus模型
单相湍流摩擦系数	0.184Re^-0.2
格架压降因子(MV/NMV/SS)	1.0/0.7/0.4
横流压降因子	0.5