Browsing by Author "Ryan, RK"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Analysis of dilute natural uranium solutions by gamma-ray excited x-ray fluorescence
    (Australian Atomic Energy Commission, 1974-06) Ryan, RK; Ridley, JL; Alfredson, PG
    Application of a gamma-ray excited X-ray fluorimeter to batch analysis of uranium solutions containing less than 10 g ℓ-1, and particularly of dilute impure solutions, is described. An outline is given of design details of the gamma-ray excited X-ray source and of the comparison of backscattered incident X-rays and fluorescent X-rays as a means of compensating for variations in the matrix solution. For pure solutions the lower limit of detection was 0.03 g ℓ-1, compared with 0.05 g ℓ-l for typical impure solutions. In the range 0.1 to 10 g ℓ-1, an accuracy of ± 5 per cent was obtained, while in the range 0.05 to 0.1 g ℓ-1, the accuracy was ± 30 per cent.
  • Thumbnail Image
    Item
    A brief survey of processes for heavy water production
    (Australian Australian Atomic Energy Commission, 1967-02) Ryan, RK
    A brief review is given of methods for the production of nuclear grade heavy water, including water electrolysis, distillation, and chemical exchange processes. Present world production comes mainly from the U.S.A., however Canadian plants will shortly produce much of the world supply. These plants use the H2O/H2S process, the only one developed to industrial scale. Sufficient development of the NH3/H2 process has proceeded for its use industrially. Heavy water production as a by-product of established industries appears attractive provided a process matched to the feed supply is available. There are many possible processes that have not been developed.
  • Thumbnail Image
    Item
    The development and testing of SYNROC for high level radioactive waste fixation
    (Australian Atomic Energy Commission, 1981-02-23) Reeve, KD; Levins, DM; Ramm, RJ; Woolfrey, JL; Buykx, WJ; Ryan, RK; Champan, JF
    Research and development on the SYNROC concept for high level radioactive waste fixation commenced at the Australian Atomic Energy Commission Research Establishment, Lucas Heights, in March 1979, in collaboration with a complementary program at The Australian National University (ANU). The present paper reports progress in the project's second year and reviews its current status. An inactive 30 kg-scale SYNROC fabrication line incorporating in-can hot pressing as the fabrication step has been built for operation in mid-1981. Atmospheric pressure and hydrothermal leach tests are demonstrating the excellent leach resistance of SYNROC. Accelerated radiation damage tests using fast neutrons are simulating damage in SYNROC for periods of close to 10/sup 6/ years. In supporting research, mineral phase development, impact friability and thermophysical properties of SYNROC are being studied.
  • Thumbnail Image
    Item
    Development of processes for pilot plant production of purified uranyl nitrate solutions
    (Australian Atomic Energy Commission, 1975-01) Alfredson, PG; Charlton, BG; Ryan, RK; Vilkaitis, VK
    Nuclear purity uranyl nitrate solutions were produced from Rum Jungle yellow cake by dissolution in nitric acid and purification by solvent extraction with 20 vol.% tributyl phosphate in kerosene using pump -mix mixer-settler contactors. The design of the equipment, experimental studies and operating experience are described. Dissolution of yellow cake and recycled uranium oxide materials was readily carried out in a 100 ℓ dissolver to give solutions containing 300 gU ℓ -1 and 0.5 to 4 П nitric acid. Filtration of silica from this solution prior to solvent extraction was not necessary in this work for yellow cake containing 0.25 per cent silica. A low acid flowsheet for uranium purification was developed in which the nitric acid consumption was reduced by 76 per cent and the throughput of the mixer-settler units was increased by 67 per cent compared with the initial design flowsheet. Nine extraction and seven scrubbing stages were used with a feed solution containing 300 gU ℓ -1 and 1.0 П nitric acid and with a portion of the product recycled as scrub solution. The loaded organic phase was stripped in 16 stages with 0.05 П nitric acid heated to 60º C to give a 120 gU ℓ -1 product. The uranium concentration in the raffinate was < 0.04 g ℓ-1, corresponding to ~ 0.01 per cent of the feed.
  • Thumbnail Image
    Item
    Development of solvent extraction processes for the H.T.G.C.R. fuel cycle, Part 1 - design of a flow-sheet for the recovery of actinides.
    (Australian Atomic Energy Commission, 1965-06) Baillie, MG; Ryan, RK
    A preliminary flowsheet for the recovery and decontamination of residual actinides in spent H.T.G.C.R. fuel has been designed. A calculation method for the multicomponent liquid—liquid extraction system H20 - UO2(NO3)2 - Th(NO3)4 - Be(N03)2 - HNO3 - TPP - Kerosene using the limited equilibrium data available is described. The flowsheet which has been designed incorporates a novel "split contactor" concept which is necessary to prevent third phase problems.
  • Thumbnail Image
    Item
    Liquid wastes from mining and milling of uranium ores - a laboratory study of treatment methods
    (Australian Atomic Energy Commission, 1976-10) Ryan, RK; Alfredson, PG
    Methods of reducing the concentration of contaminants in mine water and in the acidic raffinate from uranium milling operations have been studied. Lime, limestone, caustic soda and lime-soda ash mixtures were compared as reagents for neutralising raffinates and for removing amines and heavy metals including radium from solution. All methods of neutralisation reduced contaminant levels significantly. Two-stage neutralisation using limestone in the first stage to pH 4, followed by second stage lime treatment appears to be an economically attractive approach. This method usually gave the lowest residual radium concentration provided the solids from the first stage were not removed before adding lime. Radium can be further removed from neutralised raffinates or from mine water conditioned with sulphate by the addition of barium chloride to co-precipitate the sulphates of barium and radium. The concentration of radium was readily reduced to less than 3 pCi £-1 by adding 10 mg Ba £-1 raffinate. For mine waters conditioned to 0.01 M in sulphate, barium additions of 20 mg £-l were required to attain the same radium concentrations. Adsorption on barytes was also effective in removing radium from conditioned mine water and neutralised raffinates.