Abstract
The objective of this thesis is to develop a TRACE model for Maanshan nuclear power plant to analyze RCS pressure, which should be within 22.06 MPa of ASME Code Level C Service Limit Criterion under ATWS. Maanshan nuclear power plant is a three-loop pressurized water reactor power plant which designed by Westinghouse Electric Corporation, and its power rate is uprated to 2822 MWt by measurement uncertainty recapture since 2009. The PWR ATWS sequence starts with an anticipated transient and the electrical or mechanical failure of the RPS, and the ATWS transient results in a RCS pressure rise. According to 10 CFR 50.62 of U.S. NRC, Maanshan NPP has set up AMSAC as a backup system to actuate turbine trip and auxiliary feedwater if RTS and ESFAS were failed. According to the results, with sufficient negative moderator temperature coefficient, normal work of AMSAC and valves, RCS pressure could keep within 22.06 MPa. Furthermore, the model of SBO ATWS has been made for multiple failure analysis and discussing probable mitigation strategy. Besides, a FRAPTRAN model has been developed for analyzing fuel rod reliability, and a DAKOTA model developed for uncertainty analysis. To make sure it conforms the regulations of RCS pressure below 22.06 MPa, PCT below 1477 K, cladding hoop strain below 0.01, fuel enthalpy below 170 cal/g, and no PCMI occurred.