Improvement of CATIA2 Code Used in Optimization Design for Digital Instrument and Control System of NPP

In order to meet the requirements of the optimization design work for the digital instrument and control system of the nuclear power plant (NPP),the transient simulation program for PWR,CATIA 2 code,has been improved.The main improvements are that the digital sampling module,the digital processing time steps of the ΔT protection channels and the sample time of the input parameters for the ΔT protection channels are introduced in the CATIA 2 code.A new over temperature setpoint equation module according to the digital technology is provided.By analyzing and comparing the numerical simulation results,the improvements are proved to be reasonable and feasible.