A container for confining nuclear waste, including a sleeve of longitudinal axis closed at a first longitudinal end by a base and a second longitudinal free end via which the container is designed to be loaded, a plug configured to close the second longitudinal free end tightly, a flange fixed on the inner face of the sleeve to the side of the second longitudinal free end, the plug having at least one external diameter substantially equal to at least one internal diameter of the flange, the plug configured to be welded on the flange such that the welding zone is offset radially towards an interior of the container, relative to an inner face of the sleeve.