Identification and Authentication of Copper Canisters for Spent Nuclear Fuel by a Portable Ultrasonic System

The long-term storage of nuclear-spent fuel in geological repositories has introduced the need to develop new technologies for safeguarding the fuel. Continuity of knowledge about the fuel's location must be maintained during transport of the copper canisters that contain the fuel from the encapsulation plant to the final repository. Among the possible different containment and surveillance measures are the identification and authentication of each canister. The authors propose an innovative solution for this purpose, which is based on the ultrasonic acquisition of two fingerprints: an artificial code realized by chamfers machined in the inner surface of the copper lid (identification) and a natural signature due to the weld between the lid and the tube (authentication). Several prototypes of ultrasonic acquisition devices have been developed and tested on real copper samples to validate the identification and authentication concepts. This article describes the design of a new, optimized version of the ultrasonic acquisition device. The aim of this new design is to provide a solution for the identification and authentication of copper canisters using a portable device that is cost-effective and easy to use, which does not require the presence of an inspector in the field. The mechanical design of the reader has been upgraded with the introduction of a stepper motor and a new probe holder that includes a beam splitter to acquire two fingerprints simultaneously. The new device has been tested on copper samples, both with and without chamfers, and the results are reported in this article. The implementation of the seal fingerprint acquisition device (SFAD) within the new portable acquisition system is discussed at the end of this article with the goal of improving the electronic performance of the acquisition device in the field.