Abstract: A temporary support structure for supporting a lower internals assembly above the reactor vessel during inspection and/or maintenance thereof. A support bracket is bolted to the reactor vessel flange at the vessel head stud closure holes. A pivotally mounted arm, upon the top surface of which the internals rest, is attached at one end to the support bracket and projects radially inwardly therefrom. A compliant foot depends from the bottom of the opposite end of the arm and engages the vessel internals support ledge to provide a secure support structure for the internals assembly. An alignment bracket on the arm aligns the internals with the support. Four such structures are installed around the circumference of the vessel flange while the internals are within the reactor vessel. The structure allows the lower internals to be quickly removed from the interior of the reactor vessel and placed on the temporary supports.