Overheating study in power plant control rod banks calibration test

Power control banks-turbine load test (RGL04 test) is to be performed to verify the accuracy of calibration curve by quickly reducing the power before nuclear power plants connecting to power grid. Overheating phenomenon occurred during the tests in CPR1000 units of nuclear power plants in Ningde and Yangjiang units. This paper analyzes and evaluates the causes and the factors that lead to overheating during the RGL04 test. The overheat of the core can be predicted by calculating the theoretical value of isothermal temperature coefficient. A sound advice to avoid large superheat is given at the end of this paper.