Calculation model of controlling rod drop time

Background:Reactor drive line is the lifeline of reactor control,which performs important safety functions.Purpose:To provide the basis for the drive line design assessment and nuclear power plant safety analysis.Methods:Through analyzing the stress of pressurized water reactor control rod assembly and control rod drive mechanism,established the mathematical model and the motion equation,and then solved by the finite difference method.Results:The program calculated value accords well with the test value of Ling'ao nuclear power plant phase Ⅱ unit hot rod drop.Conclusion:The rod drop time of calculation program based on this method can be used to the safety evaluation when pressurized water reactor is shut down.