High accuracy boronometer design developed for light water reactors

Highlights: •A new high accuracy boronometer design with two optimized features are presented. •The design optimization was performed using four boronometer models. •Two-11.3 + 28.0 boronometer with R-0-4 conversion function shows the smallest error. -- Abstract: This paper presents a new high accuracy boronometer design with two optimized features: a minimized error for signal-to-boron concentration conversion and high accuracy boron concentration measurements by two-range detection. The design optimization was performed using four boronometer models that are combinations of single- and two-range detectors and high- and low-sensitivity detectors manufactured by LND and IST Inc. The boronometer's accuracy was evaluated by the root mean square (RMS) error of conversion function fitting and the RMS error of measured boron concentrations. The rational function with a 0th order polynomial in the numerator and a 4th order polynomial in the denominator showed the smallest RMS fitting error, and the two-range boronometer model with four low-sensitivity detectors (11.3 cps/nv) and two high-sensitivity detectors (28.0 cps/nv) showed the smallest RMS error for boron concentration measurement.