to and from the reactor cavity movement of the hoist 16 can be accomplished by moving the entire irmsca 100 along the d ring rails 24 or building support surface by retaining the irmsca in place and moving the hoist rail 14 along the transverse rails 15 or by a combination thereof the hoist 16 is then used to lower a hook or other coupling device in known manner to the equipment to be moved the equipment is secured to the coupling device and the hoist 16 is used to lift the equipment to the desired location where it is lowered and disconnected from the coupling device in fig1 and 20 the hoist 16 is positioned over the reactor cavity fig1 illustrates the position of the irmsca 100 intermediate the steps illustrated in fig1 and 20 here the irmsca 100 has been translated toward the left side of the page the north side of the exemplary power plant along the building support surface and the iha is visible in fig2 the crdm lead screws have been raised lifted by the hoist 16 as a prerequisite to iha removal and storage during the rfo fig2 shows the irmsca 100 at the southernmost location in the exemplary plant adjacent the end of the building support surface rails 24 25 in this position the irmsca.