Stress And Thermal Analysis And Preliminary Design Of The In-vessel RMP Coils In HL-2M

HL-2A，which is a copper conductor tokamak directed by Southwestern Institute ofPhysics (SWIP), is being modified as HL-2M. HL-2M will inherit and make full use of theconditions in HL-2A. In order to get the plasma with higher beta, longer energyconfinement time and higher bootstrap current, the auxiliary heating power in HL-2M willbe up to20MW, which makes easier to explore the reactor relevant regimes with highplasma core confinement.In order to control and study high performance and high parameter plasma, in-vesselresonant magnetic perturbation (RMP) coils are proposed for the design of HL-2Mtokamak to suppress MHD instabilities, such as edge localized mode (ELM）andresistance wall mode (RWM). The coils could also be used to compensate error field toimprove plasma confinement. Each coil is to be fed with a current up to5kA, operatedwith a frequency range of dc to about1kHz. Two set of coils (1×6,1×18) are arranged intoroidal rows in the upper half of the VV, and the in-vessel RMP coils are symmetricallylocated in the upper and lower halves. The support, insulation and vacuum sealing in avery limited space are crucial issues for designing in-vessel RMP coils, and the coils mustwithstand large electromagnetic (EM) and thermal loads. In this paper, the structure,support, insulation and vacuum sealing of the in-vessel RMP coils for HL-2M areintroduced. Finite element calculations are performed to optimize the support byminimizing stress caused by EM forces on the coil conductors, then the minimum stress isused to check the strength and get the life time of the coil. The temperature rise occurringon the coil in normal working condition and300℃baking condition are worked out, andcorresponding thermal stresses caused by thermal expansion of materials are evaluated tobe allowable. The times that take to cool down the coils in different working conditionsare also discussed.