Development and performance of a thermal conductivity cell for the measurement of UF$sub 6$-content in the process gas of a separation nozzle plant

Technical Report · Wed Aug 01 04:00:00 EDT 1973

OSTI ID:4932656

Plesch, D; Schuette, R

Essentially, adjustment and supervision of a separation nozzle cascade for the enrichment of uranium-235 is accomplished with the aid of the pressures and UF/sub 6/ concentrations of the mixture consisting of uranium hexafluoride and a light additional gas applied as process gas. For continuous measurement of the UF/sub 6/ content in the 10-stage separation nozzle pilot plant working with a mikture of 5 mol% UF/sub 6/ and 95 mol% He at absolute pressures of about 40 torr, a concentration measuring cell was developed, based on the thermal conductivity method. As a result of the suitable design of the heater element in the cell (Knudsen number 0.002 at 40 torr He), a sufficiently small pressure dependence of the concentration reading (corresponding to 0.008 mol% UF/sub 6// torr) with a detection limit of 0.01 mol% UFc in He could be obtained. It was confirmed experimentally that a noticeable influence of thermal diffusion on the concentration measurement does not occur under the operation conditions of the plant. The thermal conductivity cells mounted at the different stages of the pilot plant are connected with a common electrical supply and thermostat circuit and calibrated together. Compared with the use of autonomous instruments, this does not only reduce the expenditure of the equipment, but also improves the measuring cells' relative accuracy which is important for the adjustment of the cascade. An adjustment experiment is briefly reported, the evaluation of which gives a maximum relative error of plus or minus 0.3% of the concentration reading, corresponding to plus or minus 0.015 mol% UF/sub 6/. ( auth)

• Research Organization: Kernforschungszentrum Karlsruhe (F.R. Germany). Inst. fuer Kernverfahrenstechnik
• Sponsoring Organization: Sponsor not identified
• NSA Number: NSA-29-000917
• OSTI ID: 4932656
• Report Number(s): KFK--1824
• Country of Publication: Germany
• Language: German

Related Subjects

ACCURACY
CHEMICAL ANALYSIS
CONTROL EQUIPMENT
HELIUM
MIXTURES
N46400 --Instrumentation-- Miscellaneous Instruments
N47120 --Isotope & Radiation Source Technology--Isotope Separation (Industrial)--Uranium
N50120* --Metals
Ceramics
& Other Materials--Ceramics & Cermets--Preparation & Fabrication
SEPARATION NOZZLE METHOD
THERMAL CONDUCTIVITY
URANIUM HEXAFLUORIDE