Abstract
The objectives of this thesis are to establish AP1000 TRACE model via SNAP interface, and to verify its accuracy comparing with Westinghouse design. In the beginning, 3D vessel, steam generator and other components were separately built based on Westinghouse Design Document and independent tests were conducted to assess their accuracy. The simulation results obtained by TRACE show a good agreement with design. After that, the plant with main RCS and PXS components was modeled and the steady state calculation was implemented to acquire 100% rated power operation condition by using the transient simulation method. The calculated data was compared with Westinghouse design and prove the mode's accuracy, which can be applied to simulate the accident transient behavior in future.In this research, loss of AC power to the station auxiliaries accident which is considered as Condition II event in Westinghouse Design Document was analyzed using AP1000 TRACE model. Compared with the calculated results of LOFTRAN code developed by Westinghouse, the data simulated by TRACE shows a good agreement and reveals that the passive safety systems could establish and maintain a safety shutdown condition for the plant with the effective core cooling, mitigating the accidental consequence without operator actions when loss of all AC power sources. Thus the severe accident consequences such as the reactor core melting and radioactive leakage would be avoided. In conclusion, AP1000 TRACE/SNAP model has been established. After the commercial operation, this model could be verified by using startup tests. The animation of the model was also created to observe the thermal hydraulic parameters of plant in real time. This model could be used in safety analysis in future and offers more references for AP1000 safety operation.