关键词: CFETR；冷屏；深孔法；镀银；低活化元素 

Abstract: Based on several existing models of thermal shield structures in fusion device, an option design 
scheme for CFETR vacuum vessel thermal shield (VVTS) is proposed, which is to drill some cooling channels 
along the direction of thickness of the VVTS panel. A parallel and series connection flow path is designed for 
every inner thermal shield part. The temperature distribution of different parts of CFETR VVTS is calculated with 
finite element method. The result shows that the temperature distribution of new option is more uniform, and the 
effect of cooling is better. By means of the deep hole drilling, the maximum surface emissivity can be improved 
from 0.05 to 0.075 at a similar output radiant power. Therefore, the materials of the silver coating can be replaced 
by low activation and low surface emissivity elements such as chromium and tungsten. 

Key words: CFETR, Thermal shield, Deep hole method, Silver plating, Low activation element