Nuclear reactor monitor devices

Purpose: To improve the reliability of the reactor core monitor devices for LMFBR type reactors by combining signals from a group of rapid responsive temperature detectors at the exit of fuel channels. Constitution: A fuel channel is divided into groups and signals from temperature detectors for the individual fuel channel exit belonging to the identical group are inputted by way of a signal conversion circuit into an averaging circuit. The averaging circuit determines the average value, which is compared in an alarm circuit with a predetermined temperature. If it deviates from the predetermined level, an alarm is issued. Not all but about one-half of the temperature detectors are required and the reliability is not so dependent on the reliability of the individual temperature detectors at the fuel channel exit, and a monitor circuit with a sufficient reliability can be obtained. (Seki, T.)