Facile and Precise Detection of Boric Acid via Coulometric Titration

In order to control the reactivity in a nuclear plant, boric acid is added to the reactor coolant in pressurized water reactors (PWRs); hence, the measurement of the boron concentration in the coolant is very important. In this work, a facile and precise coulometric titration technique was proposed by placing a silver anode and a graphite cathode in the same electrochemical cell, with the addition of NaBr as a scavenger for Ag+ ions. The concentration of boric acid was calculated from the number of electrons consumed in the electrochemical titration. It was found that the number of moles of electrons, and the boron concentration over a range of 5-50 ppm, conformed to a linear function with R-2 of 0.9960. This could be a potential method for the automation and remote control of the device responsible for measuring the boron concentration in the PWR coolant, without any loss of precision.