Abstract
The new expanded version of PCTRAN has individualized the Feedwater system and Control Rod system and made users able to control and monitor the two systems in individual window. It helps to enhance the diversity and accuracy of simulation. We utilize the expanded PCTRAN to simulate and analyze the events of Anticipated Transient Without Scram (ATWS) of LungMen NPP in feedwater system. Anticipated transient without scram means an anticipated operational occurrence followed by the failure of the reactor trip portion of the protection system. At this moment alternate rod injection (ARI) system starts to insert the control rods. If ARI system fails, the control rods are inserted by Fine Motion Control Rod Drive (FMCRD) run-in system. If ARI and FMCRD systems both fail, standby liquid control system (SLCS) injects into the reactor pressure vessel a borated water solution.We analyzed three ATWS events involved feedwater systems: Loss of Feedwater, Loss of Feedwater Heating and The Feedwater Controller Failure to Maximum Demand. They are triggered separately by low water level, manual and high pressure. We contrasted the results of simulation with PSAR[1]. After a series of verifications, we affirmed the accuracy and credibility of the results of the expanded PCTRAN.