Harmonics expansion method for on-line monitoring of PWR power distribution

The power distribution of PWRs can be expended by harmonics. Combined with the detector readings, the harmonics can be used to reconstruct the reactor power distribution on-line with high speed. The accuracy of reconstruction is related to the precision of neutron detectors and the similarity of the reference case to the real one. But it is difficult to choose the reference case because the condition of the reactor is much complex. In this paper, some simulations of the reactor are done to generate a data library of harmonics for on-line monitoring of the PWR power distribution. Measurement from DAYABAY nuclear power station is used to verify the accuracy of this method. The result shows that the relative errors between the measurement and the reconstruction result is less than 3%, which satisfies the requirement of engineering.