Browsing by Author "Corran, ER"

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    HIFAR safety analysis: frequency and offsite consequences of fault sequences initiated by within-plant failures
    (Australian Atomic Energy Commission, 1986-05) McCulloch, DB; Corran, ER; Petersen, MCE; Nicholson, FD; Innes, RW
    HIFAR fault sequences, initiated by failures of within-plant equipment and operational procedures, are analysed using probabilistic methods, and their frequencies estimated. Sequence consequences are estimated in terms of potential radiation doses to an individual at 1.6 km radius from the reactor, expressed in terms of emergency reference levels recommended by the National Health and Medical Research Council for consideration of limited evacuation. The results show that the public risk from all such sequences is extremely low.
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    Seismic risks at Lucas Heights
    (The Institution of Engineers Australia, 1994-05-01) Corran, ER; Higson, DJ
    The paper discusses the earthquake potential of the Lucas Heights region, the ability of the HIFAR reactor to withstand seismic damage and the consequences of damage if it should occur. The potential for a damaging earthquake, although small, cannot be ruled out entirely and has particular significance because an earthquake could conceivably be a common cause of damage to the reactor, its protective systems and its containment. It is concluded from an assessment of seismic risk that HIFAR complies with international nuclear safety practices regarding risks to individual members of the public, and with the individual risk criteria of the NSW Department of Planning. The margin of compliance is considered sufficient to offset the uncertainties of seismic risk estimation. Assessment of the collective risk to society as a whole is less conclusive, largely because of the lack of a well established basis for societal risk assessment.
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    The seismic safety of HIFAR
    (Australian Nuclear Science and Technology Organisation, 1995-10) Corran, ER
    The 10 MW Research Reactor HIFAR is located on the edge of the Sydney conurbation. The possibility of a seismic event in this region which might damage HIFAR and lead to a release of fission products is very small but cannot be dismissed. The nature of seismic events is discussed and the local seismology has been studied, leading to estimates of the size of an event within a 10,000 y return period and of the likelihood of other sized events. The safety significant features of HIFAR are described , and the effects that seismic events of varying size might have on these features are considered. It is judged that the primary coolant circuit will withstand the 10,000 y event without failure. For very large events, a loss of coolant accident could occur, leading to fission product release. The likelihood and consequences of such events, in terms of radiation doses to the surrounding population, have been estimated. The best estimate of the likelihood that fission products might escape from the building is once in 45,000 years. The best estimate of the effective dose to the worst affected individual is 1.3mSv, less than the annual background dose in the Sydney region. The seismic safety of HIFAR has been assessed in the context of the proposed regulatory objectives of the Nuclear Safety Bureau. HIFAR is judged to meet these objectives.
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    A suggested approach for deriving risk criteria in radiation protection and land use planning
    (The Institution of Engineers Australia, 1994-05-01) Cameron, RF; Corran, ER
    In radiation protection, tolerability has been determined by setting a limit on the dose received recognizing that there is an unavoidable background level of radiation to which we are all exposed. This dose is sometimes associated with a cancer fatality coefficient to convert the dose to a probability of fatality, but it is recognised that fatality is not immediate but arises (if at all) many years after the exposure. In other hazardous industry, tolerability is based on satisfying annual fatality risk limits for the number of immediate fatalities. These limits vary with the type of land use proposed. This raises the questions of how such risks should be compared and, in particular, whether there is a basis for common risk measures to be derived. Unless this can be done, inappropriate comparisons will continue to be made. In this paper, a method is suggested for deriving measures of risk to individuals and to communities, both for activities involving radiation exposure and for accidents with other hazardous materials. The method is based on taking account of the difference between continuing releases and accidental transient releases. It is argued that the continuous releases, the lifetime risk is the most appropriate parameter both for radiation and hazardous material exposure. For accident situations both individual and societal risk curves can be drawn which take account of the difference between acute and latent fatalities. Some problems associated with societal risk curves are discussed and suggestions for their use given.