Abstract: The present invention provides visual inspection and physical access into the space of a fluid containment system consisting of an inner storage container or vessel, and an outer, reinforced precast structure, or vault, having a top cover. Visual inspection ports and physical access assemblies, with easily removable covers, are cast into the vault top corners for direct, or remote viewing, such as with a periscope or video camera device, of the exterior surfaces of the inner storage container; the interior surfaces of the outer, vaulted structure; and the space between the two structures. Sufficient physical access and physical maneuverability is provided by the visual inspection port assemblies, and corresponding visual inspection chambers directly below each port assembly, that proactive inspection to verify primary vessel integrity and removal of fluids from the interior space between the two containers can be achieved without personnel entry or removal of the vault top.