Year
2006
Abstract
Our enrichment monitor (EM) measures the enrichment of UF6 flowing through the processing pipes in a down-blending facility. It uses sodium-iodide detectors to measure the rates of a transmission-source gamma ray and the 186-keV gamma ray from 235U. Our previous EM design, installed at two facilities, used a 57Co(122 keV, T½ = 272 days) transmission source, an analog multichannel analyzer (MCA), personal computers purchased in 1997, and an early version of the data acquisition and analysis software. Its 57Co source could penetrate steel pipes, but it had to be replaced annually because of its 272-day half-life. Our new design uses 241Am(60 keV, T½ = 433 years), which never has to be replaced. It does, however, require aluminum piping because of its less penetrating gamma ray. The new design uses a digital-signal-processing MCA and updated personal computers. Its MCA has been modified to include an autoloop feature that allows it to continue acquiring and storing data if the computer fails. The vastly improved software, based on a graphical user interface, includes many user-friendly screens. A schematic of the system with colorcoded lights now indicates the status of the system, and a status screen shows important parameters, such as the number of measurement runs completed. A View-Live-Spectra screen shows the spectra as they are being acquired by the MCAs. Other screens show hardware and analysis parameters. The enrichment calibration can now be determined by merely selecting the files to be used with the mouse and entering the known enrichment for those files. Previously acquired data can be reanalyzed by simply selecting the data files and a parameter file. The new design is already operating at a third facility. This report describes the system, shows some of the software screens, and presents some examples of measurements.