A system includes a diffuser configured to receive exhaust gas from a turbine. The diffuser includes an outer barrel, an inner barrel, a seal interface, an outer aft plate, an inner aft plate, and poles. An upstream end of the outer barrel includes an upstream lip interfacing with a downstream lip of an outer wall of the turbine outlet, forming a lap joint. The outer barrel includes a plurality of axial segments disposed between the upstream end of the outer barrel and the outer aft plate, and the axial segments. The inner barrel includes a plurality of axial segments disposed between an upstream end of the inner barrel and the seal interface. The seal interface includes a groove configured to receive the inner aft plate. The poles are spaced about the turbine axis and couple an end of the outer aft plate to an end of the inner aft plate.