Final design of a 24 MW radially-cooled insert for a 45 T hybrid system

For the National High Magnetic Field Laboratory the Francis Bitter National Magnet Laboratory has designed and is fabricating a 24 MW radially-cooled insert magnet. It is to add 31 teslas or more to the 14 T of the 616 mm bore superconducting magnet of Hybrid V, a system to generate at least 45 T in a 32 mm bore. The insert embodies many innovations for the sake of housing component commonality, unobstructed access for users quick installation, efficiency, longevity and burnout isolation, while coping with power densities up to 7 W/mm³, heat flux densities to 9 W/mm², water pressures to 40 bars, and fault loads to 3.5 MN. The upper surface of the housing is free of all electrical and hydraulic clutter. The compact coil package plugs in from above. Its three coils are electrically and hydraulically in series-parallel, with inward flow through the outer two coils. High water pressure and short passages give water velocities up to 40 m/s, despite depths of only 0.10 to 0.15 mm, thus achieving outstanding cooling efficiency and a peak temperature of only 68°C. Conductors, with strengths to match local stresses, are trio thicknesses of copper, three of Be-Cu and two of 24% Ag-Cu. All have excellent combinations of strength and electrical conductivity