Dynamic characteristic analysis method of DET and RELAP5 coupling based on universal instrumental variable method

A dynamic characteristic analysis method of dynamic event tree (DET) and reactor excursion and leak analysis program (RELAP5) coupling based on a universal instrumental variable method, comprising following steps:

• S1, constructing a DET simulation model of a discrete DET, and modifying a TRIP card of an input file of a RELAP5 by adding a universal instrumental TRIP variable according to a state transition type of a DET simulation object;
• wherein the universal instrumental TRIP variable is variable type or logical type;
• S2, determining a simulation time and a current simulation step of the DET simulation object applied to the RELAP5, and running the RELAP5;
• S3, analyzing, based on a result file of the current simulation step output by the RELAP5, the result file to obtain time information of state transition control TRIP variable change of the DET simulation object;
• S4, identifying a DET branch time of state transition occurrence of the DET simulation object, and obtaining a RELAP5 restart number for the RELAP5 backtracking restart according to a branch rule of the DET simulation model;
• S5, determining the state transition type of the DET simulation object, updating a restart file for the RELAP5, and generating restart input files of a DET successful branch and a DET failed branch for the RELAP5;
• S6, determining a backtracking restart time of the RELAP5 according to the DET branch time, taking the restart input files of the DET successful branch and the DET failed branch as inputs and combining with another result file of the current simulation step calculated by the RELAP5, backtracking the RELAP5 to complete simulation of next simulation steps of the DET successful branch and the DET failed branch;
• and
• S7, repeating the process from the step S2 to the step S6 until the simulation time reaches a simulation task time specified by a user, and then finishing a dynamic coupling between DET and RELAP5.