Optimization of Method for Finding Doppler Heating Starting Point in Qinshan Nuclear Power Plant Ⅱ

Through analyzing the physical parameters and phenomenon during the tracing of Doppler heating starting point, the paper optimize the test method for finding Doppler heating starting point in Qinshan Nuclear Power Plant Ⅱ. The analysis found that when finding Doppler heating starting point, it is more suitable to use the signal of hot leg temperature of coolant temperature measuring bypass, and neutron flux rate logarithmic signal. In addition, it can avoid the misjudgment effectively in finding the Doppler heating starting point in the course of neutron ascending, and confirming once more in the course of neutron descending.