Browsing by Author "Chute, JH"

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    Electron microscope studies of irradiated beryllium metal.
    (Australian Atomic Energy Commission, 1963-05) Chute, JH
    When beryllium is irradiated by fast neutrons, helium is produced by the (n,2n) and (n,α) transmutation reactions. Electron microscopy techniques have been used to study the nucleation and distribution of helium bubbles in several different grades of beryllium, after irradiation at temperatures in the range 75 — 700ºC. The effect of post-irradiation annealing is also reported. It is shown that for similar neutron doses and irradiation temperatures, there were wide variations in helium bubble size and distribution in specimens of beryllium fabricated by different methods. The most satisfactory material was that fabricated from Pechiney powder by direct hot extrusion followed by annealing for one hour at 800ºC and air cooling, it is suggested that the helium bubbles nucleate on second phase precipitates and that the distribution of this phase is strongly affected by fabrication and heat treatment.
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    Examination of BeO irradiated at elevated temperatures in the engineering test reactor
    (Australian Atomic Energy Commission, 1964-09) Hickman, BS; Chute, JH
    A description is given of an examination of BeO samples irradiated by the General Electric Co. in the Engineering Test Reactor, Idaho Fails, to doses up to 1.2 x 1021(> 1 MeV) and temperatures in the range 470 — 1200ºC, at dose rates of 1 to 3 x 1014 nv. The results of X—ray measurements and optical and electron microscopy are presented and discussed. Comparisons are made with previously reported results on similar material irradiated in the reactor HIFAR at lower dose rates.