The present disclosure is directed to steam reformers for the production of a hydrogen rich reformate, comprising a shell having a first end, a second end, and a passage extending generally between the first end and the second end of the shell, and at least one heat source disposed about the second end of the shell. The shell comprises at least one conduit member comprising at least one thermally emissive and high radiant emissivity material, at least partially disposed within the shell cavity. The shell further comprises at least one reactor module at least a portion of which is disposed within the shell cavity and about the at least one conduit member and comprises at least one reforming catalyst. The disclosure is also directed to methods of producing a hydrogen reformate utilizing the steam reformers, comprising the steps of combusting a combustible mixture in a burner to produce a combustion exhaust that interacts with the steam reactor module(s) through surface to surface radiation and convection heat transfer, and reforming a hydrocarbon fuel mixed with steam in the steam reformers to produce a hydrogen-containing reformate. The present disclosure is further directed to reactor modules for use with the above steam reformers and methods of producing a hydrogen reformate.