Abstract: The radiation shielding door located in the main hall of the fusion device is a crucial component of the shielding arrangementss, requiring excellent neutron and photon shielding performance, while maintaining structural strength, seismic stability and airtightness to safeguard both the surrounding environment and personnel safety. Based on a composite shielding structure consisting of a 50 mm carbon steel inner layer, a 500 mm boron-doped polyethylene middle layer, and a 250 mm carbon steel outer layer, a Monte Carlo particle transport program (cosRMC) was used to simulate the shielding performance of the door. The results show that the shielding performance of the radiation shielding door exceeds that of a 1 000 mm thick concrete wall, satisfying the required shielding performance criteria. Considering the functional characteristics of the large radiation shielding door, which has a significant weight and undergoes frequent opening and closing, hinge, drive and locking mechanisms were designed. Finite element analysis performed using ANSYS software indicates that, under normal operating conditions, the main structural components exhibit maximum equivalent stresses of 25.9 MPa, maximum shear stresses of 13.8 MPa, and maximum deformations of 0.048 mm; under seismic design basis conditions, the corresponding values are 30.2 MPa, 16.1 MPa, and 0.052 mm, respectively.All values meet thd design requirements.

Key words: fusion device, radiation shielding door, shielding performance, structural design