Abstract: EAST(Experimental Advanced Superconducting Tokamak) conducts plasma fusion by deuterium and deuterium, which releases large amounts of neutrons and secondary gamma rays. In order to accurately understand the spatial distribution of radiation products in the EAST fusion device under the condition of high parameter long pulse plasma discharge, the radiation on-line monitoring system is used to realize the effective monitoring of neutron and γ rays. According to protection requirements, 13 key monitoring areas are arranged inside and outside the EAST installation hall. In terms of monitoring system hardware, radiation neutrons and γ rays are detected by ionization chamber based on BF₃ proportional counter tube and argon respectively, and monitoring data are transmitted to acquisition machine through twisted pair and Ethernet hybrid networking mode. The monitoring system software adopts the control acquisition software based on LabVIEW to collect and store the real-time dose rate and cumulative dose of neutron and gamma rays. The monitoring results show that the maximum radiation dose rate in the hall of the EAST fusion device rapidly increases by more than 3 orders of magnitude under the long pulse and high parameter plasma operation condition, and then drops to the radiation background level soon after the discharge. The radiation dose rate outside the hall is always kept close to the radiation background level due to the protective effect of the shielding wall. The online radiation monitoring system can not only effectively obtain radioactive data, but also provide data support for radiation safety protection management to ensure the safe development and utilization of fusion energy and personnel safety.

Key words: EAST, neutron, γ ray, radiation monitoring