ULTRASONIC IDENTIFICATION AND AUTHENTICATION OF CONTAINERS FOR HAZARDOUS MATERIAL

A container for nuclear and/or hazardous material, the container comprising a container body made of metal and a lid made of the same metal as the container body, the lid and container body being made of adapted to be welded together to form a sealed container. The lid comprises a plurality of scannable elements, the scannable elements being spatially distributed on the lid (e.g. equally spaced at the circumferential perimeter) and adapted to be scanned with an ultrasonic scanner. One or more of the scannable elements is an inclined surface element, each inclined surface element being inclined relative to the axis of the lid. In use, scanning of the scannable elements with said ultrasonic scanner produces a first scan signal, the first scan signal being dependent upon which of said scannable elements are inclined surface elements. A method of identifying and/or authenticating a container is also disclosed in which a third (identification/authentication) signal is derived from the intersection of the first signal and a second scan signal obtained by scanning the signature surface element.