Nuclear Techniques ›› 2015, Vol. 38 ›› Issue (11): 110601-110601.

• NUCLEAR ENERGY SCIENCE AND ENGINEERING •

### Simulation study on detachment operation of snowflake divertor for CFETR

WU Haosheng1 MAO Shifeng1 CHEN Bin1 ZHANG Chuanjia1 LUO Zhengping2 GUO Yong2 PENG Xuebing2 YE Minyou1

1. 1(University of Science and Technology of China, Hefei 230026, China) 2(Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China)
• Received:2015-09-15 Revised:2015-10-26 Online:2015-11-10 Published:2015-11-13

Abstract:

Background: In the conceptual design of China Fusion Engineering Test Reactor (CFETR), two additional poloidal coils, with respect to International Thermonuclear Experimental Reactor (ITER), are used to generate snowflake divertor configuration proposed recently for the purpose of exploring effective way for reducing heat loads onto divertor targets. Heat flux onto divertor targets was dramatically reduced in detached regime, while the performance of impurity screening would also be reduced due to the decrease of divertor temperature. Purpose: This study aims to simulate the detachment operation of snowflake divertor for CFETR. Methods: The detachment operational status was investigated by numerical simulation based on the edge plasma simulation software SOLPS (Scrape-off Layer Plasma Simulation). A D2 gas puffing in the main chamber was used to change plasma density. Results: When the gas puffing rate was sufficiently high, snowflake divertor of CFETR was completely detached, and the ion flux and heat loads onto the targets significantly decreased. However, the plasma temperature in the divertor region was too low and the impurities could easily pass through the X-point to core plasma, which implied a risk of radiation instability. Conclusion: Therefore, a proper operational status for the snowflake divertor in CFETR should be partial detachment.