Thermo-hydraulic reasons for the Local Power Range Monitor (LPRM) spiking

► New reason for LPRM spiking based on the occurrence time and plant conduction, as power, flow rate, has been developed. ► A equation has been developed to predict the evolution of power during LPRM spiking events. ► The values of power, core flow rate and recirculation flow rate are given to predict the appearance of spiking. ► Finally the LPRM spiking is related to early bistable flow events, when the bistable events are very reduced in time.