Year
2016
Abstract
Gas centrifuge enrichment plants (GCEPs) are the most important facilities for international safeguards, and the method of continuous measuring the separative work unit (SWU) capacity of GCEPs is regarded as the most effective and efficient approach. For GCEPs which feeds are natural uranium hexafluoride (UF6), its SWU capacity can be measured continuously by online monitoring the mass flow and the enrichment of the products and the enrichment of the tails. UEOM-I Type Online Uranium Enrichment Monitor, which mainly consists of a chamber, a ? ray detector, a pressure gauge and a thermometer, is designed for online and unattended and remote measuring the enrichment of the products, the ? ray detector is used to measure the count rates of the gamma rays in the energy region from 143keV to 186keV emitted by 235U nuclide, and the total quantity of uranium is determined from thermodynamic characteristics of gaseous UF6 by the pressure gauge and the thermometer. Because the enrichment of the tails are far below than that of the products, the background of the monitor and the enrichment of the gaseous UF6 in the chamber can be determined simultaneously after measuring the ? ray spectral in different pressure adjusted by controlling the electromagnetic vales at the inlet and outlet of the chamber. The experiment results show that the relative standard deviation (RSD) of the measured enrichments of the tails is less than 1.5% and the deviation of the measured background count rates of the monitor to their real count rates is less than one count per second (cps) when the measurement cycle is about 3 hours,which indicates UEOM-I Type Online Uranium Enrichment Monitor can be used for continuous measuring the SWU capacity of GCEPs.