  The capability of Free-Electron Lasers to generate photon beams with record
performances in the domain of MeV-class photon energy for nuclear photonics
applications is here analyzed. We discuss possible nuclear FEL working points.
Some typical situations are presented and simulated by means of the
three-dimensional code GENESIS 1.3. The losses by spontaneous emission and by
wakefield induced energy spread are then evaluated. The calculations show the
possibility of generating FEL radiation at 1-4 MeV with less than 300 eV of
bandwidth with not prohibitive set up requirements, achieving therefore regimes
where no other kind of gamma ray sources could arrive.
