Online Estimation of Decay Ratio using Short Time Fourier Transform Ridge for Flow Instability Detection in Natural Circulation Boiling Water Reactors

Abstract

This paper proposes a novel method for online estimation of decay ratio using Short Time Fourier Transform ridge, to aid in detection of the onset of thermal-hydraulic instabilities in Natural Circulation Boiling Water Reactors. It estimates the time-varying decay ratio and instantaneous frequency of the instabilities. The accuracy and speed achieved by the method make it suitable for online implementation for stability monitoring. The proposed method is validated with simulated data as well as experimental data obtained from a thermal-hydraulic test facility.