压水堆轴向功率重构几何矩阵研究

Geometric Matrix Study of Axial Power Reconstruction for Pressurized Water Reactors

基于多项式拟合,推导了从堆外核仪表探测器电流信号重构轴向功率算法中的几何矩阵模型。通过数值计算与工程测量数据对适用于CPR1000堆型的几何矩阵模型进行了验证。针对不同数目节功率信号与适用于自给能探测器信号功率重构的几何矩阵模型进行了推导。对4段节功率输入信号的功率重构结果进行了误差分析,并探讨了输入信号数目对拟合精度的影响。研究结果表明:几何矩阵的本质是将有限个节功率输入扩展为全轴向分布的一种映射关系,其包含了节划分、轴向外推距离与功率重构点位置等几何信息;4段节功率重构后功率分布的精度不能满足工程应用要求,应使用自给能探测器信号作为功率重构输入。

A geometric matrix model in the axial power algorithm for reconstructing current signals from off⁃heap nuclear instrumented detectors is derived based on polynomial fitting.The geometric matrix model applicable to the CPR1000 reactor type is validated by numerical calculations and engineering measurement data.It is derived for different numbers of section power signals with the applicable geometric matrix model for power reconstruction of self⁃feeding energy detector signals.The error analysis of the power reconstruction results of the 4⁃segment section power input signals is carried out,and the influence of the number of input signals on the fitting accuracy is discussed.The results show that:the nature of the geometric matrix is a mapping relationship that extends the finite section power input to the full axial distribution,which contains geometric information such as the section division,the axial extrapolation distance and the position of the power reconstruction point;the accuracy of the power distribution after the 4 segment section power reconstruction does not meet the requirements of engineering applications,and the self⁃contained energy detector signals should be used as the input for power reconstruction.