A support structure for supporting a pressurizer safety and relief valve system above a pressurizer vessel comprises a ring girder which surrounds the pressurizer vessel wall and is supported on pairs of lugs spaced about the pressurizer wall. The ring girder supports columns for the system at locations spaced from the lugs, and support means in the form of frames distribute the load on the lugs. The frames have upper and lower bars and outer vertical bars, with spaced inner vertical bars. Biasing means are provided to attach the frames to the lugs and distribute the forces, and a projection on the ring girder fits into a groove of a support bar on the upper bar of the frame.