Field Trial of an Unattended Verification Station for UF6 Cylinders

In recent years, the International Atomic Energy Agency (IAEA) has pursued innovative techniques and an integrated suite of safeguards measures to address the verification challenges posed by the front end of the nuclear fuel cycle. Among the unattended instruments currently being explored by the IAEA is an Unattended Cylinder Verification Station (UCVS) that could provide automated, independent verification of the relative enrichment, 235U mass, total uranium mass, and identification for UF6 cylinders processed in front-end facilities (e.g., uranium enrichment plants and fuel fabrication plants). Under the auspices of the United States and European Commission Support Programs to the IAEA, a project was undertaken to assess the technical and practical viability of the UCVS concept. At the core of the U.S. component of this viability study is a long-term field trial of a prototype UCVS system at the Westinghouse Fuel Fabrication Facility in South Carolina, USA. The prototype incorporates two nondestructive assay (NDA) methods being considered for inclusion in a UCVS (the Hybrid Enrichment Verification Array and the Passive Neutron Enrichment Meter), as well as load cells, surveillance cameras, automated data acquisition and remote data retrieval. This paper begins with a description of potential UCVS implementation concepts at an enrichment plant, including the use of an “NDA Fingerprint” to provide periodic, high-fidelity verification that the contents of a given cylinder are unchanged from previous scans. This implementation vision provides context for discussion of the field-trial objectives; hardware and software of the UCVS prototype design; and different scanning procedures employed to address specific technical questions posed by the IAEA.