Browsing by Author "Smith, PD"

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    Development of ceramic coatings for fission product retention in ceramic fuels.
    (Australian Atomic Energy Commission, 1966-01) Smith, PD; Reeve, KD
    A general discussion on glaze—type coatings for fission product retention within BeO spheres fuelled with PuO2 - ThO2 particles is presented. From these considerations, a glaze thickness of 0.004 inch was chosen as a basis for laboratory studies. Glaze development commenced with a conventional high temperature glaze; this was modified firstly by increasing the SiO2 content and then by progressively replacing some of the SiO2 by Ti02, Zr02. Ti02 - Zr02, BeO2 and BeO plus Ti02. Glaze structures varied from amorphous to predominantly crystalline. When applied to fuelled BeO cubes, some glazes failed to cover fuel particles and others tended to react with them, Two of the most promising glazes behaved poorly in fission product release experiments, probably because glaze—fuel interaction had allowed fuel migration to the glaze surface-It is concluded that glaze type coatings show little promise for the present applications.
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    The effect of axial flaws on the burst pressure of stainless steel tubing
    (International Institute of Welding, 1976-08-23) Kelly, PM; Brown, KR; Smith, PD; Zybenko, B
    A study has been made of the failure of 321 stainless steel tubes containing artificial axial defects. The data agree well with mathematical analyses that are available in the literature to predict the effect of defects on the failure stress of pressurised tubes fabricated from tough materials. Satisfactory agreement was obtained although the experimental pressurisations were performed without an axial stress component, whereas the analyses are normally used for structures in which an axial stress is developed.
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    Linear thermal expansion of thoria, urania-thoria, and their dispersions in beryllia in the range 20-1000°C, together with improved data for beryllia
    (Australian Atomic Energy Commission, 1967-08) Turner, DN; Smith, PD
    Differences in the thermal expansion properties of the dispersed phase and matrix of a beryllia based fuel can give rise to stresses in the material on cooling. In beryllia the strains can be very large. By means of a dilatometric method the linear thermal expansion properties of thoria, urania -thoria L(U,Th)O2 with U:Th = 1:10 J and dispersions of 20 vol. per cent of each in beryllia for the range 20—1000ºC have been measured. The results are given, together with some improved data for beryllia. The data obtained for thoria are compared with published data and the thermal expansion of composite bodies is discussed. There is evidence that the particles of the dispersed phase are bonded to the matrix.
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    Studies of the effect of thickness on the fracture toughness of grade 300 maraging steel, part 1.
    (Australian Atomic Energy Commission, 1977-06) Smith, PD; Brown, KR
    A series of tests was carried out using the ASTM fracture toughness test standards as a basis to determine the variation in fracture toughness of maraging steel (grade 300) of thickness ranging from 10 to 1 mm. Although these standards are not strictly applicable to maraging steels of the lower thicknesses in this range, they yield a measure of fracture toughness which can be used to predict safe operating stresses for thin walled the structures. A maximum fracture toughness of approximately 90 MPa m was obtained at 1 mm, the minimum thickness examined. The plane strain fracture toughness was approximately 58 MPa m at thicknesses greater than 5 mm.
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    The vacuum hot pressing of beryllium
    (Australian Atomic Energy Commission, 1964-03) Clare, TE; Smith, PD; Wright, WJ
    The optimum conditions for vacuum hot pressing of Pechiney electrolytic beryllium powder have been established and compacts produced with densities exceeding 99 per cent, of theoretical density; these conditions depend markedly on the geometry of the compact and the oxide content of the powders being pressed, Effects of compact geometry, including low densities in long compacts, are associated with loss of pressure through die—wall friction, particularly where the length—to—diameter ratio of the compacts is greater than 0.5 . The presence of 2.3 per cent, beryllium oxide as a surface film on the particles reduced the final density attained to less than 97 per cent, of theoretical when pressing with 1500 lb/in2 at 1080ºC whereas this density could be attained in unoxidised powder with only 800 lb/in2 for similar conditions. The narrow size range of the oxidised powder may also have contributed to this difficulty in pressing.