Design and verification of the in-vessel cooling water system for the EAST lower tungsten divertor

Abstract

The Experimental Advanced Superconducting Tokamak (EAST) aims at more than 400 s long-pulse H-mode operations with a full metal wall and a divertor heat load of 10 MW/m2 in the next machine operation phase. However, currently the lower graphite divertor heat handling capability is restricted to less than 2 MW/m2. Therefore, the lower divertor and lower corresponding components are demanded to be upgraded. The in-vessel plasma facing components (PFCs) cooling water system (CWS) providing water to the lower divertor is important, which requires to meet cooling requirement according to the related heat load of PFCs. This paper describes the latest EAST in-vessel CWS. The conceptual design procedure of the in-vessel CWS for EAST lower tungsten divertor is detailed presented. Hydraulic and structure analysis are performed. The pressure drop is within acceptable range of design requirement. The resultant stress and displacement meet the requirement of the design code and standard. According to the test of EAST lower divertor in-vessel CWS prototype, the test and simulation data are provided to prove that the design is rational and the minor difference of structure and weld have a little effect on water pressure drop. These results show that the design of the in-vessel CWS for EAST lower divertor at present meets the requirements, which give a strong support to the next design phase.