Digitalized instrument control system monitoring unit division method in nuclear power plant maintenance rule

The invention belongs to the technical field of nuclear power plant maintenance, and particularly relates to a digitized instrument control system monitoring unit division method in nuclear power plant maintenance rules. Comprising the following steps: step 1, classifying all nuclear power plants and DCS related systems, and respectively determining systems divided into large units and small units; 2, screening all important functional equipment, and respectively determining equipment needing high-precision, medium-precision and low-precision monitoring; step 3, classifying specially considered equipment into a monitoring unit with a specific system function; step 4, integrating the overlapping and crossing functions to merge and split the monitoring units; and 5, analyzing the historical data, and supplementing the equipment with more failure times or long unavailable time in the monitoring unit. And step 6, verifying and evaluating division rationality and maintenance operability of the monitoring units in