Storage container for spent nuclear fuel with improved closing

A container for confining spent nuclear fuel, comprising:

• a sleeve of longitudinal axis comprising a first longitudinal end closed by a base and a second longitudinal free end via which the container is configured to be loaded;
• a plug configured to close the second longitudinal free end tightly by a weld made at a level of a welding zone, the welding zone being offset radially towards an interior of the container, relative to an inner face of the sleeve;
• and
• a flange projecting from the inner face of the sleeve to a 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.

A process for loading and closing a container for confining spent nuclear fuel including:

• a sleeve of longitudinal axis including a first longitudinal end closed by a base and a second longitudinal free end via which the container is configured to be loaded,
• a plug configured to close the second longitudinal free end tightly by a weld made at a level of a welding zone, the welding zone being offset radially towards an interior of the container, relative to an inner face of the sleeve,
• a flange projecting from the inner face of the sleeve to a 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,
• the process comprising:
• placing the loading inside the container;
• placing the plug in the flange;
• welding the plug on the flange without adding material.