Fluoride Volatility Process Research Articles

In-Line Gas Chromatograph for Analysis of UF6 and/or F2

With the view of continuous analysis of UF6 and/or F2 in the fluorination of U for the development of the fluoride volatility process, an in-line gas Chromatograph, made of anti-corrosive materials against the fluorides, has been constructed using two different columns and automatic sampling system. The separation columns used, were optimized for the simulated process gas composition {(N23, O2, F2)/(UF6) = 18, (N2, O2)/(F2) =3.3}, in order to obtain the complete peak separation. The column selected for UF6 analysis is 0.4 cmø Cu tubing of 3 m long packed with 40% of poly-trifluoromonochloro-ethylene oil which is loaded on poly-tetrafluoro- ethylene powder. The column for F2 analysis is the combination of the above column with a conversion column of 0.4 cmø tubing of 2 m long packed with KCl powder. Under these column conditions, the analytical time is 9 and 3 min for UF6 and F2, respectively at the flow rate of 100 ml/min. The calibration curves are linear with a zero intercept, and the analytical limits are, respectively 0.2 and 1 mmHg in partial pressures of UF6 and F2 with 10 ml of sampling volume. In actual adaptation to the fluorination of uranium oxides, the in-line gas Chromatograph was satisfactorily able to measure the reaction rate and to detect the end of fluorination.

Behavior of ruthenium in fluoride-volatility process—II. Fluorination of RuO 2 by F 2

RuO 2 was fluorinated by F 2 in the temperature range 250–500°C. Mass spectrometry confirmed that the reaction product was RuOF 4. Small amount of RuO 4 was produced as a by-product in the fluorination. Temperatures higher than 400°C were necessary to convert RuO 2 smoothly into RuOF 4. IR absorption spectrum of RuOF 4 was obtained. The product is an unstable material and tends to decompose into RuF 4, releasing oxygen. Discrepancies with earlier published literature were discussed.

Behavior of Ruthenium in Fluoride-Volatility Process, (I)

Behavior of Ruthenium in Fluoride-Volatility Process, (I)

Behavior of Ruthenium in Fluoride-Volatility Process, (I)

Behavior of Ruthenium in Fluoride-Volatility Process, (I)

Authors and Papers

Authors and Papers

Engineering Development of a Fluidized-Bed Fluoride Volatility Process. III. Bench-Scale Studies with Irradiated Uranium Alloy Fuels

In six experiments using fluidized-bed fluoride volatility techniques to process irradiated uranium-Zircaloy and uranium-aluminum alloy fuels, less than 1% of the uranium was retained in the reacto...

Cathodic Protection in Molten Fluoride Salts at 1200 F

Abstract Corrosion is a major problem in the Fluoride Volatility Process for recovery of nuclear fuel. Relatively large scale pilot plant developments are under way by the Chemical Technology Division of the Oak Ridge National Laboratory. In this process fuel is dissolved by hydrogen fluoride in a molten bath consisting of mixtures of such salts as NaF-LiF-ZrF4. Usual operating temperatures are near 1200 F (649 C). Because metals such as stainless steel and zirconium are to be dissolved in this process it is obvious that the salt mixture must be quite corrosive. This is particularly true because HF is sparged through the bath continuously. Experiments were carried out at Battelle on a laboratory scale to determine the feasibility of using cathodic protection to reduce the attack in process vessels. Polarization curves were developed under simulated operating conditions for the materials of interest, i.e., Inor-8, Zircaloy and graphite. Polarization characteristics were obtained by use of a potentiostat using platinum as a reference electrode and graphite as an anode. Experiments using rectangularly shaped coupons were carried out to determine the amount of protection furnished by the impressed current technique in the most corrosive salt composition. Specimens were made cathodic at current densities ranging from 3 to 50 amp/ft2. Excellent protection was furnished to the submerged portions of the specimens. However, severe attack occurred at the interface at reasonable current densities.

Fused-Salt Fluoride-Volatility Process for Recovering Uranium from Spent Aluminum-Based Fuel Elements

Fused-Salt Fluoride-Volatility Process for Recovering Uranium from Spent Aluminum-Based Fuel Elements

Engineering Development of a Fluid-bed Fluoride Volatility Process IBench-Scale Studies

A fluid-bed volatility process, developed for the recovery of uranium from highly enriched uranium-zirconium and uranium-aluminum alloy fuels, involves separating the alloying material as a volatil...

Engineering Development of a Fluid-bed Fluoride Volatility Process IIPilot-Scale Studies

As a step in the development of a new reprocessing method for spent nuclear fuels, a fluoride volatility pilot plant has successfully demonstrated the recovery of uranium as uranium hexafluoride fr...

Engineering Developments in Fluoride Volatility

Fused salt handling in the fluoride volatility process for production of UF/sub 6/ was investigated. In addition, the reaction of fluorinating agents with fused salt melts and the distillation of inorganic compounds wene examined. Fused salt process lines were made of Inconel and electrically heated by tubing wall resistance. Equipment for fused salt-gas reaetions included a dip tube, a percolator tube, and a sieve plate. Application of this equipment is described along with a discussion of the theory of contacting efficiency in bubble beds and the effect of variables such as vessel content stirring on the reaction efficiency. In distillation investigations it was concluded that the height equivalent to a theoretical plate for systeras involving UF/sub 6/ or other dense substances may best be found by doubling the value obtained for hydrocarbon systems. (J.R.D.)