Design of an Unattended Environmental Aerosol Sampling and Analysis System for Gaseous Centrifuge Enrichment Plants

摘要

The resources of the IAEA continue to be challenged by the worldwide expansion of nuclear energy production. Gaseous centrifuge enrichment plants (GCEPs) represent an especially formidable dilemma to the application of safeguard measures, as the size and enrichment capacity of GCEPs continue to escalate. During the early part of the 1990's, the IAEA began to lay the foundation to strengthen and make cost-effective its future safeguard regime. Measures under Part 1 of'Programme 93+2' specifically sanctioned access to perform environmental sampling by IAEA inspectors. During inspections, IAEA inspectors collect environmental swipe samples that are then shipped offsite to an analytical laboratory for enrichment assay. This approach has proven to be an effective deterrence to GCEP misuse, but this method rarely achieves the timeliness goal for high-enriched uranium (HEU) detection set forth by IAEA. Furthermore it is questionable whether the IAEA will have the resources to maintain pace with the expansive production capacity of the modern GCEP, let alone improve the timeliness in confirming current safeguards conclusions on facility misuse. New safeguards propositions, outside of familiar mainstream safeguard measures, may therefore be required that counteract the changing landscape of nuclear energy fuel production. A new concept is proposed that offers rapid, cost effective GCEP misuse detection, without increasing LFUA inspection access or introducing intrusive access demands on GCEP operations. Our approach is based on continuous onsite aerosol collection and laser-based enrichment analysis. This approach mitigates many of the constraints imposed by the LFUA modality, reduces the demand for onsite swipe sample collection and offsite analysis, and overcomes current limitations associated with in-facility misuse detection devices. Automated aerosol environmental sample collection offers the ability to collect fleeting uranium hexafluoride emissions before they are lost to the ventilation system or before they disperse throughout the facility, to become deposited onto surfaces that are contaminated with background and historical production material. Onsite aerosol sample collection, combined with enrichment analysis, provides the unique ability to quickly detect stepwise enrichment level changes within the facility, leading to a significant improvement in timeliness of verification results. We report in this paper our study of a conceptual GCEP environmental sample release and simulation results of a newly designed aerosol collection and particle capture system that is fully integrated with the Laser Ablation, Absorbance Ratio Spectrometry (LAARS) uranium particle enrichment analysis instrument that was developed at the Pacific Northwest National Laboratory (PNNL).