中文摘要：

采用谐波展开法进行堆芯三维功率分布的在线监测,将堆芯三维功率分布用中子扩散方程的谐波进行展开,并利用堆内探测器读数信息进行展开系数的求解;采用非线性半解析节块法结合Krylov子空间法进行全堆芯谐波的求解,其计算时间约为采用细网差分法结合Krylov子空间法求解的1/100。基于谐波展开法理论开发堆芯三维堆芯功率分布在线监测系统NECP-ONION,采用国内典型压水堆电厂实测数据对该系统进行验证。结果表明,组件平均功率的在线监测系统重构值与电厂测量值之间均方根误差小于2%,基于谐波展开法开发的在线监测系统具有很高的计算精度。

英文摘要：

This paper studied the on-line monitoring of PWR 3D power distribution based on the harmonics expansion method. In this method, the power distribution is expanded by the neutron diffusion equation＇s harmonics. And the expansion coefficients are calculated based on the in-core detector measurements. Non-linear iteration semi-analytic nodal method combined with Krylov sub-space method is used to obtain the harmonics of neutron diffusion equation. This nodal method is 100 times faster than the fine-mesh finite differencing method combined with Krylov sub-space method for harmonics calculation. A 3D power distribution on-line monitoring system named NECP-ONION （On-line monitoring system） has been developed based on the harmonics expansion method. Measurements from a typical PWR core in China are used to validate this system. Numerical results show that the root-mean-square errors of assembly averaged powers are less than 2%. NECP-ONION has high calculation accuracy.