Effectiveness Analysis for Core Coolant Monitoring System during Medium Loss of Coolant Accident

In order to validate the effectiveness of core coolant monitoring system（CCMS） of CPR1000（improved Chinese PWR） unit under condition of Medium Loss of Coolant Accident（MLOCA）,and quantitatively analyze the water level calculation difference of two judgement methods of main coolant pump status in the control system,the measuring principle of the CCMS are analyzed.The level and error of CCMS calculation under these two conditions are calculated quantitatively using RELAP5-3D program to simulate the thermal hydraulic part of CPR1000 unit and virtual DCS to simulate the control system.The result shows that two methods both induce large error;the judgement of the core level by operator may be misled in the view of State Oriented Procedure（SOP）.