Browsing by Author "Connolly, JW"

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    Analysis of hypothetical loss-of-control-arm accidents in HIFAR
    (Australian Atomic Energy Commission, 1986-11) Connolly, JW; Clark, N
    The reactor power transient produced in the HIFAR materials testing reactor upon severance of a central coarse control arm connecting rod and the subsequent pivoting of the arm out of the core has been calculated for a range of reactor conditions likely to be encountered in normal operation. It is concluded that as long as the remaining arms of the control arm bank can be relied on to suppress the post power peak oscillations in power the reactor will withstand the consequences of such an accident.
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    An analysis of power transients observed in SPERT 1 reactors
    (Australian Atomic Energy Commission, 1976-04) Clancy, BE; Connolly, JW; Harrington, BV
    The analytical method described in Part I of this series has been applied to the calculation of SPERT I transients performed with higher initial moderator temperatures and also to those performed in a highly undermoderated core. Reasonable agreement has been obtained between calculated and experimental burst data.
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    Analysis of power transients observed in spert i reactors, Part 1 - transients in aluminium plate-type reactors initiated at ambient temperature
    (Australian Atomic Energy Commission, 1975-03) Clancy, BE; Connolly, JW; Harrington, BV
    An investigation of SPERT I reactor reactivity feedback mechanisms has been made using the modular code AUS. Feedback terms so obtained have been used in the transient analysis code ZAPP to calculate transient behaviour for step and ramp reactivity additions. A simple model of coolant boiling has been used to analyse transients for which cladding temperatures exceed the saturation temperature of water. The generally good agreement obtained with experimental data supports the case that core only temperature coefficients are much larger than those obtained by heating core and reflector.
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    Analysis of power transients observed in the SPERT II deuterium oxide moderated close packed core
    (Australian Atomic Energy Commission, 1977-09) Connolly, JW; Harrington, BV
    Power transient behaviour of the very under-moderated SPERT II core B18/68 is analysed. The experimental conditions included core pressurisation and forced coolant flow. Generally good agreement is obtained between measured and calculated data.
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    An analysis of self-terminating power transients in the reactor HIFAR
    (Australian Atomic Energy Commission, 1978-02) Connolly, JW; Ferguson, HD
    Consequences of step reactivity additions above critical have been calculated for HIFAR under conditions of no coolant flow and the operating coolant flow rate of 400 kgs. In particular, the maximum core excess reactivity that will allow loss of a central coarse control arm blade from the core has been determined. In order to perform these calculations a cylindrical geometry version of the neutron kinetics, heat transfer code ZAPP has been written and tested against the experimental data from the SPERT III-E oxide core. The results of this comparison are given as an appendix to this report.
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    Integral reaction rates and neutron energy spectra in a well moderated reactor.
    (Australian Atomic Energy Commission, 1963-04) Connolly, JW; Rose, A; Wall, T
    Cadmium ratio measurements in the internal reflector of MOATA haev been made with gold, indium, tungsten, manganese, molybdenum, and copper detectors. These measurements have been analysed on the assumption that the neutron spectrum consists of a Maxwellian distribution to which is smoothly joined a 1/E slowing down spectrum, cross sections being averaged according to the methods of Westcott. A search through recent literature suggests that the s factors for gold and indium listed by Westcott are in error. If this is accepted then it appears that the measured epithermal spectrum is closely 1/E in form for neutron energies between one and six hundred eV. The corrections to be applied when foils of finite thickness are used in cadmium ratio measurements are discussed, and the spectrum derived from these measurements has been used to calculate reaction ratios of cooper: indium and copper: gold alloy foils. These ratios have been compared with measured values. Values of the effective resonance integral of Pt198 wire detectors have been measured, and from these values an estimate has been made of the infinitely dilute resonance integral of this isotope.
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    Measurement and calculation of slow power transients in the university training reactor, Moata
    (Australian Atomic Energy Commission, 1977-09) Connolly, JW; McCulloch, DB
    Self-limiting transients of initial period down to ~ 12 s have been measured in the AAEC's 100 kW Moata (University Training Reactor (UTR)) and the results compared with the predictions of a point-kinetics heat transfer model (ZAPP code). Although natural convection significantly affects the burst shape of such slow excursions, calculation and experiment are sufficiently in agreement to give confidence that the ZAPP model, which has been well tested against SPERT I data, can be successfully applied in safety studies for this class of reactor to predict the consequences of reactivity additions up to the onset of core melting.
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    The science and engineering of HIFAR safety
    (Australian Nuclear Science and Technology Organisation, 1993-12-01) Connolly, JW; Clancy, BE; Beattie, DRH; Robinson, GS; Godfrey, RM; Harrington, BV
    Since the HIFAR Safety Document was first issued major improvements have occurred in the quality of data and in the methods of calculation which are available for deterministic analysis of the behaviour of the reactor in normal or in accident conditions. Many such analyses have been carried out but the results have been reported in a wide range of internal memoranda and in external reports. In this report the most significant of the improved methods are described and the results of some of those analyses are reviewed. Principal areas covered are reactor physics of the core and reflector the dynamics of the control systems thermal hydraulic aspects important to safety margins and the emergency core cooling system. Abnormal events discussed are inadvertent reactivity insertion sequences and the loss of coolant accident. Where possible consistent sets of data are provided for use in future analyses.