CLIQ Protection Design for the Graded Nb$_{3}$Sn Research Racetrack Dipole Demonstrator (R2D2)

Abstract

The Research Racetrack Dipole Demonstrator (R2D2) is being studied as a demonstrating magnet for future FCC magnets. The R2D2 is meant to prove the feasibility of grading in block-coil Nb 3 Sn dipoles and explore quench behaviors at a very high current. This short model provides an opportunity to study quench protection concepts which will be needed for the full-scale FCC magnets. Both quench heaters and CLIQ (coupling loss induced quench) are under study. This paper presents the research work on the CLIQ protection. The work includes CLIQ design methods and configurations, and comparative studies of various CLIQ configurations for maximizing the CLIQ effectiveness. The results show that the most effective CLIQ configuration is able to quench 80% of the coil turns at the nominal current within 3 ms, leaving 20 ms for detection and validation time while keeping the maximum hotspot temperature within 350 K. The study shows that protection of R2D2 using only CLIQ may be feasible under certain assumptions.

Quench Protection of Nb3Sn High Field Magnets Using Heaters, a Strategy Applied to the Graded Racetrack Dipole R2D2

“…The second goal is to evaluate the feasibility of only quench heaters-based protection in the R2D2, and outline directions for future protection design studies. In parallel, an analysis of the feasibility of only CLIQbased protection was carried out [6]. The combination of heater and CLIQ will be carried out at a later stage.…”