Year
2008
Abstract
The continuous enrichment monitor, developed and fielded in the 1990s by the International Atomic Energy Agency, provided a go-no-go capability to distinguish between UF6 containing low enriched (approximately 4% 235U) and highly enriched (above 20% 235U) uranium. This instrument used the 22-keV line from a 109Cd source as a transmission source to achieve a high sensitivity to the UF6 gas absorption. The 1.27-yr half-life required that the source be periodically replaced and the instrument recalibrated. The instrument’s functionality and accuracy were limited by the fact that measured gas density and gas pressure were treated as confidential facility information. The modern safeguarding of a gas centrifuge enrichment plant producing low-enriched UF6 product aims toward a more quantitative flow and enrichment monitoring concept that sets new standards for accuracy, stability, and confidence. An instrument must be accurate enough to detect the diversion of a significant quantity of material, have virtually zero false alarms, and protect the operator’s proprietary process information. We discuss a new concept for advanced gas enrichment assay measurement technology. This design concept eliminates the need for the periodic replacement of a radioactive source as well as the need for maintenance by experts. Some initial experimental results will be presented.