Safeguards measurements for long-term storage of spent fuel

Spent-fuel wastes containing nuclear material that will be stored in long-term repositories will probably be safeguarded to some level. Containment and surveillance will be the principal safeguards mechanisms, but depending on the adopted safeguards criteria, nondestructive assay may also be necessary. There are only four likely possibilities for measuring spent-fuel wastes. (1) Detailed measurements could be made on the fuel at the shipping facility as the fuel is being loaded into the shipping/storage container. (2) The containers could be monitored on receipt at the storage facility. (3) Automated, unattended systems integrated into the facility could monitor container movement within the facility. (4) Verification instrumentation built into the storage container could be used to continuously monitor contents. Of the four measurement possibilities, only measurements at the shipping facility could be performed effectively with equipment transported to the facility for that purpose. At a storage facility where measurements are made on containers rather than individual items, best results require that the system be designed into the facility. In this paper, the authors discuss the type of measurements that might be made either at the shipping or at the storage facility and the practicality of such measurements