Sensitivity and uncertainty analysis for the PWR online power-distribution monitoring with NECP-ONION system

•The sensitivity and uncertainty analysis model has been implemented in NECP-ONION.•The analytical method is used to quantify the relative sensitivity coefficients.•BEAVRS benchmark is used to verify the sensitivity and uncertainty analysis model.•Monitoring errors with various expansion orders are analyzed.•Sensitivity and uncertainty analysis is carried out with various expansion orders.