The High Field Magnet Laboratory of the Radboud University is constructing a 45 T hybrid magnet system. The measures taken to accept the largest fault forces that can result in the not so unlikely event of failure of parts of the resistive insert magnet, dominate the design of the support structures, in particular those coupling the room temperature resistive insert magnet with the superconducting coil in the cryogenic environment. The largest fault forces arise when half of the insert coil becomes electrically short-circuited in a burn-out accident, and in the case due to the inductive coupling of the resistive and superconducting magnets the mutual axial forces may be as high as 2.5 MN. The mechanical design should guarantee that the structures can sustain these forces with no catastrophic failure.
We will argue, based on evidence of actually observed failure of resistive magnets and models of the observed failure modes, that the fault forces that may realistically occur will be much smaller. In this paper we will elaborate the measures taken in the construction of the resistive insert and superconducting outsert magnets to safely handle the fault forces.