METHOD AND SYSTEM FOR CHECKING ENRICHMENT OF URANIUM HEXAFLUORIDE Russian patent published in 2002 - IPC

FIELD: analyzing physical properties of materials in isotope-separating processes of nuclear materials. SUBSTANCE: proximate inspection of uranium hexafluoride for enrichment in gas phase is made by measuring counting rate of ²³⁵U isotope radiation detector in the course of measuring temperature and pressure of gas phase when admitting uranium hexafluoride to measuring chamber. Uranium hexafluoride enrichment is found from formula ε = α•I_γ•T_g/p_g, where α is calibration factor determined during instrument adjustment; I_γ is counting rate of gamma-ray detector, s^-1; T_g is absolute temperature of gas phase, K; p_g is absolute pressure of gas phase, Pa. Detector counting rate is estimated as absolute difference between counting rates of gamma-ray detector in measuring chamber before and after uranium hexafluoride admission. In addition gas phase temperature is evaluated by wall temperature of measuring chamber. All measurements are made within time interval and their mean values are used for calculations. Uranium hexafluoride enrichment checkup system has measuring chamber accommodating ²³⁵U isotope gamma-ray detector, pulse counter with gamma-channel adapter, internal data-exchange interface unibus connected to data acquisition, control, and processing whose output functions as data-exchange output channel of checkup system. The latter is provided in addition with timer and logic switch; measuring channel has in addition temperature and pressure sensors whose outputs are connected through data exchange adapters and internal interface unibus to data acquisition, control, and processing unit. Output of gamma-ray channel adapter is connected to input of logic switch whose output functions as pulse counter input. Timer output is connected to input of logic switch and its input, to data acquisition, control and processing unit over internal interface unibus. Proposed method and system enable essential automation and centralized control of isotope- enrichment cascade due to instant response to emergency deviations of ²³⁵U isotope concentrations from normal value and reduction of transfer and operation time with subquality product and changes in desired enrichment of UF₆. Cascade checkup is provided by using simple adaptive control means. EFFECT: facilitated checkup procedure; reduced cost of measurements and their time interval. 6 cl, 2 dwg