Browsing by Author "Watson, GM"

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    Assessment of radioactive fallout arising from testing of nuclear weapons in the South Pacific and the probable effects on the Australian population
    (Australian Atomic Energy Commission, 1973-03) Fry, RM; Symonds, JL; Watson, GM
    The first part of this report gives a short description of the different basic types of nuclear weapon and lists Chinese weapons tests in the northern hemisphere and French weapons tests in the South Pacific by date, together with an indication of the power of each device where such information is available. The second section of the report discusses the measurement of radiation and what dose units are appropriate for assessment of the significance of fallout exposure to man, and outlines the background of natural and man-made radiation to which man is inevitably subject. The principal biological effects of radiation are then identified and the nature of the relationship between radiation dose and the incidence of effects is examined. Conventional radiation protection philosophy assures a linear relationship between dose and effect, which is independent of dose rate, On this assumption it is possible to derive, from the limited high-dose data available, risk coefficients for radiation effects which may be used to calculate the incidence of harmful effects from the low radiation doses relevant to fallout studies. The difficulties and inaccuracies inherent in this extrapolation mean that estimates made in this way are essentially of the upper limits of possible damage, not the most likely value which may often be zero. The final section assesses the magnitude of fallout in Australia from the French and Chinese series of tests and expresses this in the form of dose commitments to man; the dose commitment for any radionuclide being the dose received to date plus the dose to be received in the future from residual long-lived activity already incorporated in the body and remaining in the environment. From these dose commitments, using generally accepted risk coefficients, estimates of the upper limits of the magnitude of the harmful effects, carcinogenesis and mutagenesis, which may be attributed to fallout from the respective series have been derived for the Australian population.
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    Effects of ionizing radiation on man
    (Australian Atomic Energy Commission, 1975-08) Watson, GM
    This paper describes the major effects of ionizing radiation on man and the relationship between such effects and radiation dose, with the conclusion that standards of radiological safety must be based on the carcinogenetic and mutagenic properties of ionizing radiation. Man is exposed to radiation from natural sources and from man-made sources. Exposure from the latter should be regulated but, since there is little observational or experimental evidence for predicting the effects of the very small doses likely to be required for adequate standards of safety, it is necessary to infer them from what is seen at high doses. Because the formal relationship between dose and effect is not full understood, simplifying assumptions are necessary to estimate the effects of low doses. Two such assumptions are conventionally used; that there is a linear relationship between dose and effect at all levels of dose, and that the rate at which a dose of radiation is given does not alter the magnitude of the effect. These assumptions are thought to be conservative, that is they will not lead to an underestimate of the effects of small radiation doses although they may give an overestimate.
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    Environmental hazards of fossil and nuclear power production.
    (Australian Atomic Energy Commission, 1972-06) Watson, GM
    It is now essential for engineers to recognise the environmental hazards which may be associated with their constructions and to make proper allowance from them when costing different solutions to a problem. Both nuclear and fossil-fuelled power stations present environmental hazards, and these can be traced from mines through processing plants to power station wastes. It is necessary that engineers develop an appropriate basis of comparison if they are to assess the relative environmental costs of nuclear and fossil-fuelled power stations; this must allow for effects on health, ecological effects and aesthetic effects. The biological effects of radiation have been fairly well quantified with respect to major exposures, but there is still uncertainty on the precise form of dose-response relationships at low doses, such as might be relevant to industrial and public health. There are also uncertainties for non-radioactive pollutants, and it is probably not very logical to treat the dose-effect relationships of radioactive and chemical pollutants as being quite different in nature, as is commonly done at present. There are internationally accepted standards for allowable radiation exposure. It is possible to base allowable discharges of radioactive contaminants to the environment on these standards, provided the modes of dispersion are understood and possible pathways to the exposure of man are recognised. The philosophy of radiation protection recognises that although radiation risks can be made very small, they cannot be abolished entirely, and that these risks must be balanced against the benefits of using radiation. These risks can be quantified and compared with other hazards of work and life which people accept, voluntarily or involuntarily. There are insufficient data available on the effects of health of various pollutants, and there is too little public agreement on the relative worth of mined and unmined natural resources, to allow a detailed comparison of the environmental hazards of nuclear and fossil-fuelled power stations, but it is possible to begin this comparison in limited areas.
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    Plutonium
    (Australian Atomic Energy Commission, 1976-01) Watson, GM
    Discovery of the neutron made it easy to create elements which do not exist in nature. One of these is plutonium, and its isotope with mass number 239 has nuclear properties which make it both a good fuel for nuclear power reactors and a good explosive for nuclear weapons. Since it was discovered during a war the latter characteristic was put to use, but it is now evident that use of plutonium in a particular kind of nuclear reactor, the fast breeder reactor, will allow the world's resources or uranium to last for millennia as a major source of energy. Plutonium is very radiotoxic, resembling radium in this respect. Therefore the widespread introduction of fast breeder reactors to meet energy demands can be contemplated only after assurances on two points; that adequate control of the radiological hazard resulting from the handling of very large amounts of plutonium can be guaranteed, and that diversion of plutonium to illicit use can be prevented. The problems exist to a lesser degree already, since all types of nuclear reactor produce some plutonium. Some plutonium has already been dispersed in the environment, the bulk of it from atmospheric tests of nuclear weapons.
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    Proceedings of the AAEC symposium on environmental and radiological safety aspects of the mining and processing of uranium, Lucas Heights, 9-10 December 1971.
    (Australian Atomic Energy Commission, 1973-04) Warner, RK; Watson, GM; Davy, DR; Hardy, CJ; Button, JCE; Cook, JE; Conway, NF
    Review of world trends in the uranium industry (a summary); Philosophy of environmental protection and control; Sources of pollution in uranium mining and processing activities (a summary); Environmental studies for uranium provinces - aims and methods; Methods of control of potential pollutants (a summary); Introduction to radiological safety; Radiological health and safety aspects of uranium mining and ore treatment; Biological effects of radiation; History of radiation effects and control in uranium mining; The nature of the dosimetry problem; Practical dosimetry in uranium mining; Prospects for control of radiological hazards in uranium mining.
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    Rum Jungle environmental studies summary report
    (Australian Atomic Energy Commission, 1975-09) Watson, GM
    Sources of pollution were identified and their relative importance assessed. Observations were made on seasonal variations and differences were noted between the dispersion patterns of several metals of interest. The geographical extent of chemical and biological pollution was examined. Some understanding of the basic mechanisms involved in continuing pollution was obtained and an attempt was made to determine the fate of heavy metals.