In this paper, fuzzy control approaches are used to model human expert knowledge in fault tolerance of nuclear power plant. Firstly, the reactor in a nuclear power plant model was built using Matlab based on pressure features of a primary circuit within a nuclear power plant. Secondly, a fuzzy controller was designed to control pressure of the reactor model based on the expert experience. Thirdly, the different type of faults: sensors faults, actuator faults and plant faults, were added to the reactor model during the control process based on the fuzzy controller. Finally, the performance of the fuzzy controller was evaluated using normal running and fault tolerant test case.