Abstract: A steam generator upper support arrangement provides restraint to the steam generator during operating and non-operating conditions, for loading forces resulting from seismic and postulated accident conditions, while allowing for free thermal expansion of the steam generator in the radial, lateral, and vertical directions. Four embodiments of the present invention are described. In a first embodiment, inclined bumpers are placed at predetermined angles with respect to the load path, such that as the steam generator is thermally displaced the placement and incline angles of the bumpers will compensate for the expansion and maintain a nominal gap therebetween. In a second embodiment, the variable shim mechanism comprised of cams, bumper rods, and a pivoted linkage between the steam generator and the building structure maintains the nominal gap for the required support. In the third embodiment, a single small snubber is utilized.