[en] A fuel assembly for a fast-neutron reactor consists of a shroud having an upstream end and a downstream end. The shroud houses fuel elements having portions filled with fissionable and raw materials. Corresponding fission-gas plenums are supplied to collect the gaseous products of fission and a shell. The fission-gas plenums are divided into central and peripheral groups, and at least one of the groups is located downstream of the coolant before the portions of fuel elements filled with fissionable and raw materials. The shell is placed inside the shroud with a clearance with respect to its walls and is secured at one of its butt ends to the downstream end of the shroud