Design, analysis and remote handling compatibility for a CFETR long leg divertor concept

•The upgraded divertor geometry has been designed, which was called CFETR long leg divertor.•The CFETR long leg RH compatibility divertor structure was designed in detail.•Remote handling of assembly and maintenance procedures for first wall, cassette and cooling water pipes were designed.•Analysis of preliminary pressure drop, thermal-mechanical, electromagnetic force and seismic on divertor were done. CFETR (China Fusion Engineering Test Reactor) is in its engineering design now. There are two options for divertor, helium-cooled and water-cooled, the water-cooled one was focused in this paper. The upgraded divertor geometry has larger parameters in several directions, which was proposed from the beginning of 2020. Especially, the outer leg (the distance from X-point to the outer strike point) reaches 2.4 m, which is much longer than previous version. Basing on the overall layout of vacuum vessel, the divertor module could not be replaced through the lower ports. The first wall was separated from cassette and removed through upper port, and the cassette was replaced through upper port. The CFETR long leg RH compatibility divertor structure will be designed in detail. The remote handling of assembly and maintenance procedures were also designed, including the first wall separated from cassette and removed through upper port. The first wall was installed, welded and tested, and the cassette was RH assembled and maintained through upper port. Design results showed that the upgraded divertor has good compatibility with remote handling assembly and maintenance requirement. At last, the preliminary pressure drop analysis, thermal-mechanical analysis, electromagnetic force analysis and seismic analysis of the divertor system were done. The analysis results showed that the structure design could meet the operation requirements of CFETR. Maybe there are many design and analysis options for the remote handling compatibility of CFETR long leg divertor, this paper summarized one of the latest achievements in design and analysis. All the results will be of great reference for the CFETR divertor optimal design.