A fuel module comprises an enclosure and a fuel chamber. In one exemplary embodiment, the fuel chamber comprises a primary containment tank contained within a secondary containment tank. The enclosure comprises a plurality of exterior enclosure walls and a plurality of interior enclosure walls that cooperate to form the secondary containment tank such that the primary containment tank is disposed between the exterior enclosure walls and the interior enclosure walls. In another exemplary embodiment, the exterior enclosure walls and the interior enclosure walls cooperate to form a single-walled fuel chamber disposed between the exterior and interior enclosure walls of the fuel module. Additional exemplary embodiments include fuel chambers configured as any multiple-wall structures, whether double-wall, triple-wall, or other, that comprise a plurality of containment tanks.