Development of On-line Uranium Enrichment Monitor of Gaseous UF₆ for Uranium Enrichment Plant

An on-line enrichment monitor was developed to measure the enrichment of UF₆ flowing through the processing pipes in uranium enrichment plant. A NaI(Tl) detector was used to measure the count rates of the 185.7 keV γ-ray emitted from ²³⁵U, and the total quantity of uranium was determined from thermodynamic characteristics of gaseous uranium hexafluoride. The results show that the maximum relative standard deviation is less than 1% when the measurement time is 120 s or more and the pressure is more than 2 kPa in the measurement chamber. Uranium enrichment of gaseous uranium hexafluoride in the output end of cascade can be monitored continuously by using the device. It should be effective for nuclear materials accountability verifications and materials balance verification at uranium enrichment plant.