Browsing by Author "Nicholson, KP"

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    Fast neutron flux and spectrum measurements in HIFAR
    (Australian Atomic Energy Commission, 1961-03) Nicholson, KP; Quealy, WR
    This report presents the results of measurements on the fast neutron fluxes and energy spectra in the core and 2V experimental facilities of HIFAR using threshold detectors. The following reactions were used: P31(n,p)Si31, S32(n,p)P32, Ni58(n,p)Co58, A127(n,α)Na24. The total fission flux in the flux scanning tubes were found to be 23 ± 3 per cent. of the total effective flux at the same position, having a maximum value of 4.3 x 10 13 neutrons cm-2 sec-1 (approximately 8.3 MW thermal), for a maximum effective flux of 1.7 x 10 14 neutrons cm-1 sec-1. A neutron energy spectrum differing only slightly from a fission spectrum shape was found in all positions. The use of the Ni58(n,p)Co50 reaction as a fast flux monitor is discussed.
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    Fast neutron flux and spectrum measurements in HIFAR - first supplement - average fission spectrum cross section for Ni58(n.p)Co58
    (Australian Atomic Energy Commission, 1961-10) Boldeman, JW; Nicholson, KP
    The Ni58(n.p)Co58 reaction cross section in a fission spectrum has been re-measured and found to be 102 + 3 millibams.
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    Materials for the control of nuclear reactors
    (Melbourne University Press on behalf of The Australian Atomic Energy Commission, 1958-06-02) Wright, WJ; Nicholson, KP
    The desirable properties of neutron absorbers are discussed, and the investments for the equivalent absorption in various materials are calculated. Physical and metallurgical limitations exist in the use of boron and cadmium, and the investment for blackness compared to burn-up in hafnium is unattractive. The rare earths, gadolinium, samarium and europium are discussed; dispersions of the oxides in steel are suggested for use as control elements in future high temperature reactors.