Abstract: The China Spallation Neutron Source(CSNS) is an accelertor-based high-power and high-intensities project, the duct shielding structure is an important problem during the radiation protection design. From the radiation safety aspect for the staff working in the Linac Kaystron Hall, this paper adopts the M-C program FLUKA to simulate the duct shielding effect, which located in the main-auxiliary tunnel of Linac and the roof of the auxilary tunnel. After comparing some shielding optimization projects, this paper provides the improved suggestion for duct shielding according to the simulated results and the restricted dose value of the working place.

Key words: CSNS, FLUKA, duct shielding, dose