Study on Life Extension of AP1000 Nuclear Power Plant CORE

At the end of AP1000 plant core life,the critical boron concentration required to maintain full thermal power conditions reaches approximately 7 ppm.To achieve full power conditions,it is necessary to perform a core life extension during end of life（EOL） conditions.The paper,in the base case,analyzes the methods to control the turbine throttle valve and decrease the average coolant temperature,making the plant gain an additional 17 days of rated full power operation.Furthermore,the effect of the moderator temperature coefficient（MTC） and the number of high pressure feedwater heaters out of service have also considered in a sensitivity analysis.The result shows that,the more negative the MTC,the smaller the decreasing rate of the core coolant average temperature and the longer the core life.However,in two sensitivity cases,the plant will separately gain an additional 12 days and 54 days of rated full power operation.