SURVEILLANCE OF NEUTRON FLUX IN NUCLEAR REACTOR AND APPARATUS FOR NEUTRON MEASUREMENT

摘要

PURPOSE:To intend to suppress downgrading of an extent of a thermal melting by transmitting suppression signal against output rise in case that a predetermined value, as a function of a ratio which is a ratio of the maximum neutron flux value of each local region to a signal of a core average neutron flux value, surpasses the signal of a core average neutron flux value. CONSTITUTION:The inside of a core is divided into a plurality of local regions, signals from neutron flux detectors 10a to 10d belonging to each local region are averaged by an averaging circuit 20 and neutron flux signals a of local regions are transmitted. Each neutron flux signal ai of local regions gets its maximum value MAXai determined by a maximum value detector circuit 50. Signals from the detectors 10a to 10d are averaged by an averaging circuit 30 with signals from neutron flux detectors in other local regions, and then a core average neutron flux signal b is transmitted. The maximum value MAXai and the signal b are input to a function generator 60 to generate f(MAXai/b) as a function of these ratios. A predetermined value f(MAXai/b) is compared to the signal b by a comparator 70 and when the signal b surpasses the predetermined value f(MAXai/b), a suppression signal against an output rise is transmitted.