FIELD: nuclear power engineering; identification of abnormal drop of control rod into core. SUBSTANCE: signals coming from detectors mounted along control-rod drop path are delayed so that they arrive approximately simultaneously; signals exceeding threshold value are coherently summed up, integrated, differentiated, and then applied to monitoring device. Device implementing this method has detectors whose outputs are connected to common summing section connected to monitoring device. Delay section, differentiating section, and threshold- value section formed by one or more programming computers are placed between them. EFFECT: enhanced speed of identifying abnormal drop of control rod into core. 14 cl, 10 dwg
