Abstract: A normal-closed steam-relief panel is provided in the design of the spent fuel cooling system for CAP1000 nuclear power plant. Saturated steam is released from the spent fuel pool to fuel handling area under loss of cooling scenarios. The steam-relief panel will be opened in order to mitigate the pressurization process in the fuel handling area after the fusion of the fusible links, designed to yield at an appropriate temperature. A three-dimension temperature field and pressure response to the fuel handling area was performed using GOTHIC8.0 code in this paper. The results show that temperature stratification behavior is expected depending on different time sequence. At time of about 7500 s, the steam-relief panel is expected to be opened with distinct pressure decreasing in the fuel handling area and maintain a low pressure level after that.