Browsing by Author "Ridal, A"

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    ANSTO's radioactive waste management policy: preliminary environmental review
    (Australian Nuclear Science and Technology Organisation, 1996-05) Levins, DM; Airey, PL; Breadner, B; Bull, PS; Camilleri, A; Dimitrovski, L; Gorman, T; Harries, JR; Innes, RW; Jarquin, E; Jay, G; Ridal, A; Smith, AM
    For over forty years radioactive wastes have been generated by ANSTO (and its predecessor the AAEC) from the operation of nuclear facilities the production of radioisotopes for medical and industrial use and from various research activities. The quantities and activities of radioactive waste currently at Lucas Heights are very small compared to many other nuclear facilities overseas especially those in countries with nuclear power program. Nevertheless in the absence of a repository for nuclear wastes in Australia and guidelines for waste conditioning the waste inventory has been growing steadily. This report reviews the status of radioactive waste management at ANSTO including spent fuel management treatment of effluents and environmental monitoring. It gives details of: relevant legislative regulatory and related requirements; sources and types of radioactive waste generated at ANSTO; waste quantities and activities (both cumulative and annual arisings); existing practices and procedures for waste management and environmental monitoring; recommended broad strategies for dealing with radioactive waste management issues. Detailed proposals on how the recommendations should be implemented is the subject of a companion internal document the Radioactive Waste Management Action Plan 1996-2000 which provides details of the tasks to be undertaken milestones and resource requirements.
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    Fabrication of U233/aluminium fuel plates for a sub-critical assembly - a second report
    (Australian Atomic Energy Commission, 1967-08) Bardsley, J; Ridal, A
    Uranium-233 (as 938..66 g uranium dioxide) was fabricated into 176 full-size, 20 'half-size' and 2 'quarter-size' aluminium clad fuel plated. Each full-size plate contained 5 compact and 'half-size' and 'quarter-size' plates contained 2 compacts and 1 compact respectively; a compact consisted of a cold-pressed dispersion of about 1.5 g of uranium dioxide in aluminium. The technique involved mixing uranium dioxide and aluminium powders, pressing the compacts in a steel die, end-loading them into a prefabricated aluminium can and end-welding the can; following this the can underwent radiographic inspection for uniformity, decontamination, leak detection and acceptance tests, and final decontamination. Maximum permissible radiation doses to hands and bodies of the operators were not exceeded.
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    An improved method for extruding and sintering beryllium oxide.
    (Australian Atomic Energy Commission, 1967-08) Bardsley, J; Ridal, A
    A technique for the extrusion and sintering of beryllium oxide to produce high density, fine-grained, high strength material were modified and improved. This resulted in beryllium oxide (250 p.p.m. Fe) which after extrusion and sintering for 5 hours at 1400oC in nitrogen, had an average grain size 6 pts, a mean modulus of rupture equal to 34.840 p.c.i. when tested in 4-point bentiac and a density range of 2.86 to 2.90 g cm-3. Further modifications reduced the variations in grain size and density of the sintered specimens and increased the mean modulus of rupture. For example, double extruded material, when sintered for 6 hours at 1400oC in nitrogen had an average grain size of 8pm, a density of 2.92 g cm-3 and a mean modulus of rupture of 45,300 p.s.i.
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    Spent HIFAR fuel elements behaviour under extended dry storage
    (Australian Nuclear Science and Technology Organisation, 1994-09) Ridal, A; Bull, PS
    Previously unpublished observations of the behaviour of HIFAR spent fuel under extended dry storage conditions are reported. The two fuel elements EC802 (Mark III type) were irradiated in 1966 first examined in hot cells in 1967 and again examined in hot cells in 1983 following 16 years of stage 11 years of which were in the ANSTO engineered dry storage facility. The elements showed negligible deterioration over this extended dry storage period lending considerable confidence to the viability of dry storage technologies for the long term storage of spent aluminium clad research reactor fuels.