Essay review - Nuclear radiation, radioactivity and safety

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  • This article was downloaded by: [Case Western Reserve University]On: 16 October 2014, At: 00:52Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: MortimerHouse, 37-41 Mortimer Street, London W1T 3JH, UK

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    Essay review - Nuclear radiation, radioactivity andsafetyDerry W. JonesPublished online: 08 Nov 2010.

    To cite this article: Derry W. Jones (2003) Essay review - Nuclear radiation, radioactivity and safety, ContemporaryPhysics, 44:1, 77-79, DOI: 10.1080/00107510302715

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  • Essay review

    Nuclear radiation, radioactivity and safety

    DERRY W. JONES

    Review of Practical Applications of Radioactivity and

    Nuclear Radiations. By G.C. LOWENTHAL and P.L. AIREY.

    (Cambridge University Press, 2001). Pp. xvii+337. 65.00,

    US $95.00 (hbk). ISBN 0 521 55305 9. Scope: textbook.

    Level: specialist and non-specialist.

    In the space of a few months around the end of 1895, two

    remarkable discoveries, each leading to a Nobel Prize,

    introduced the world to ionizing radiation and opened the

    way to fundamental advances in the physics and chemistry

    of the atom, the constitution of matter, and the periodic

    table of the elements. Ro ntgen's observation that `X-rays'

    were formed when cathode rays impinged on solids was

    followed by Becquerel's discovery that phosphorescent

    potassium uranium sulphate emitted penetrating rays that

    could aect a photographic plate. Within another 4 years

    investigations by Thomson, Rutherford, P. and M. Curie

    and Villard had shown that radioactive elements, which

    now included polonium and radium as well as uranium,

    emitted three kinds of radiation: positively charged a-particles, negatively charged b-rays or electrons, and g-rays,that is, X-rays of short wavelength.

    Almost immediately after their discovery, X-rays were in

    use for medical diagnosis and soon afterwards for therapy,

    while the techniques and applications of X-ray crystal-

    lography and medical and industrial radiography have

    developed steadily from World War I onwards, throughout

    the twentieth century. Likewise, radioactivity was quickly

    utilized in cancer treatment but the scope for widespread

    academic, industrial and medical applications was greatly

    enhanced when the experimental production of radioactive

    elements or radionucleotides was initiated by I. Curie and

    F. Joliot in the 1930s. Before long it was evident that

    radioactive isotopes could be obtained from almost any

    element so that over 2000 radioisotopes are now known, of

    which about 200 are regularly used in industry. World War

    II ended with a catastrophic demonstration of the power of

    nuclear energy and the adverse consequences of radiation

    from military weapons, but, by late in the twentieth

    century, about 17% of the world's distributed electricity

    was generated by nuclear power stations. (Although

    nuclear electricity generation may be declining in Europe

    and the USA, it is increasing in the Pacic region of the

    Organization for Economic Cooperation and Develop-

    ment). In addition, small low-power research reactors (and

    other sources) produce neutrons and radionuclides. During

    the second half of the twentieth century, not only have

    radioactivity and beams of X-rays and neutrons provided a

    wealth of new (especially structural) information in

    chemistry, physics and biology, but also the range of

    industrial and technological applications of radionuclides

    has increased enormously. For example, a-particles from241Am ionize air in millions of smoke detectors, b-particlesmonitor the thickness of thin lms, papers, plastics or

    coatings, g-ray gauges measure the levels in industrial tanksand hoppers, while neutron activation analysis is utilized in

    archaeology, agriculture, mineral processing, etc.

    The attitudes of practitioners and the public to radiation

    hazards has varied markedly with time, place and context.

    Injury to pioneering experimenters a century ago occurred

    understandably through lack of knowledge but, even in mid

    century, few precautions were taken during military tests,

    while research laboratory X-ray tubes were often shielded

    merely by strips of lead cut from old plumbing. Nuclear

    power stations and waste disposal can excite large-scale

    demonstrations in Germany but are suciently acceptable

    in France that electric power is exported to the UK.

    Throughout the Cold War, many nations maintained in

    reserve elaborate systems for monitoring the radiation

    eects of nuclear bombs on populations, agriculture and

    public services. Until the early 1990s, the UK Warning and

    Monitoring Organisation could monitor changes in dose

    rate at 870 observer posts; radiological information

    (simulated on exercises) was passed via sector and group

    controls so that Home Oce volunteer scientic advisors

    could predict radiation eects of nuclear fallout and so, in a

    Contemporary Physics, 2003, volume 44, number 1, pages 7779

    Contemporary Physics ISSN 0010-7514 print/ISSN 1366-5812 online # 2003 Taylor & Francis Ltdhttp://www.tandf.co.uk/journalsDOI: 10.1080/00107510210167045

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  • nuclear emergency, assist local authorities. Concurrently,

    UK public enquiries were concerned with perceived

    potentially harmful eects, for example near nuclear power

    stations, that seemed small in comparison even with

    peacetime doses due to radon in houses or natural radio-

    elements in local soil and rocks. Of course, for many

    hazards the perception of risk by the media and the public

    (which planners and governments quite properly have to

    take account of) often diers markedly from the technical

    assessment. Additionally, some risks arising from what are

    regarded as voluntary activities are more readily accepted

    than those which are regarded as imposed. The long-term

    risks of smoking and the daily totals of deaths of small

    groups of people from road accidents receive much less

    coverage than the occasional occurrence of multiple deaths

    from rail travel. Less obviously, radiological risks in

    hospitals are subject to negligible media scrutiny compared

    with that applied to the siting of nuclear installations

    (which may well produce radionuclides highly benecial in

    medical treatment).

    Radiation damage to the body occurs from two eects.

    Above a threshold, high dose rates result in rapid damage

    to cells, with death or injury proportional to the severity of

    the dose typically occurring within days. These determinis-

    tic eects are in contrast with stochastic eects in which the

    probability, rather than the severity, of harm increases with

    increasing size of dose. Such damage to deoxyribonucleic

    acid in cells may take many years to become evident as a

    cancer or may result in inherited abnormalities; moreover,

    the high and widespread natural incidence of malignancy

    and mutagenesis aggravates the diculty of predicting

    long-term risks due to radiation.

    Safety in the laboratory, workplace and elsewhere is now

    covered by an extensive literature and ruled by many

    national and international regulations, monitored locally

    by advisory ocers and nationally by health and safety,

    and radiological protection authorities. The realistic overall

    principle is to keep exposure as low as reasonably

    achievable. In terms of the unit of eective radiation dose,

    namely millisievert (mSv), whereby energy is transferred to

    living tissue with due allowance for biological eectiveness

    of the radiation, the recommended steady-state limits are

    20 mSv per year for a radiation worker and 1 mSv per year

    for a member of the public. Until the Chernobyl accident in

    1986, there were remarkably few peacetime cases known

    publically where these limits were seriously exceeded. The

    steam (rather than nuclear) explosions at the antiquated

    RBMK reactor at Chernobyl power station in April 1986

    released ssion products that were distributed widely over

    northern Europe but the maximum dose to the public in

    these countries was only about the same as the annual

    individual exposure to natural background radiation

    (1 mSv). In the former Soviet Union, however, there were

    many fatal and severe casualties; tens of thousands of

    clean-up workers received serious doses of perhaps

    100 mSv, and about 300 000 of the public are thought to

    have received doses of the order of 40 mSv.

    Chernobyl increased public and political awareness, not

    to say fears of radiation and a more profound recognition

    of the international consequences of large-scale accidents

    involving radiation. It is also possible that stringent safety

    precautions and regulations may sometimes dissuade

    potential users of radionuclides from applying tracers to

    otherwise suitable industrial or other problems. Over the

    years, there have been many introductory texts, specialized

    monographs and ocial handbooks covering the funda-

    mental science, application techniques and safety practice

    of radioactivity and nuclear radiation. However, such has

    been the extent to which practical applications of X-rays,

    neutrons and radionuclides and emitted radiations have

    continued to develop and change throughout the twentieth

    century that a new introductory monograph is not

    redundant. Lowenthal and Airey are past and present

    scientists of the Australian Nuclear Science and Technol-

    ogy Organization with much experience of industrial

    applications and of international organizations setting

    standards for measurements, metrology and safety. Their

    aim is to enable non-specialist scientists and technologists,

    teachers and students, to become aware of the range and

    principles of the safe practical applications of isotopes and

    radiation, especially in industry and the environment. For

    most working chemists and physicists, the fullment of this

    aim requires extensive foundation material about the

    science of radioactivity, sources, detection and instrumen-

    tation; fewer of these topics seem to be covered in

    undergraduate courses (and a fortiori, in schools) than

    was the case a decade or two ago, partly perhaps because of

    contemporary health and safety regulations. Accordingly,

    more than half the monograph is devoted to the science and

    technology of radioactivity, the characteristics of radio-

    nuclides and radiations, and the safe and eective use of

    instrumentation for measurements.

    An introductory chapter on nuclear stability and

    activation, neatly merging the early history of the subject

    with reminders of relevant nuclear chemistry and physics,

    outlines the wide range of radioisotope half-lives. The

    authors then deal with standards, dosimetry and radiation

    protection and make brief reference to radiation eects on

    biological tissue. This basic information is backed by

    references to both long-standing and recent works,

    although I would have preferred them to be given chapter

    by chapter rather than at the end; surprisingly, the 1988

    papers of Fujii and Takiue on assaying dual-labelled

    samples by sequential Cerenkov counting are not men-

    tioned. There is also a simple but useful glossary of terms,

    although unfortunately not one of abbreviations and

    acronyms. Chapter 3 describes the sources, scattering,

    attenuation and interaction physics of a-particles and b-

    Essay review78

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  • particles and g- and X-rays and includes a brief descriptionof Bremsstrahlung and uorescent X-rays. Two chapters

    then cover the instrumentation for detection and counting

    of b- and g-rays, including an introduction to semiconduc-tor detectors in which the authors caution users that

    contact with manufacturers is necessary to keep up with

    developments in high-performance detectors and signal-

    processing equipment. While the source preparation and

    quenching problems of liquid scintillation counters are

    referred to, there is no mention of Cerenkov counting

    which can be used for moderately high-energy b-particleemitters in solution or solvents, avoiding additive contam-

    ination of the sample. A chapter on measurements

    emphasizes the need for standards, including secondary

    and working standards, and the problems caused by de-

    excitation of b-particle decay, and concludes with a sectionon errors and statistics.

    The applications part of the book is well supplied with

    tables which often provide a helpful summary for a batch of

    applications dealt with subsequently in more detail. A

    chapter on industrial applications of radioisotopes and

    radiation embraces process control, computerized tomo-

    graphy, neutron borehole logging, and food preservation,

    to mention a few from a wide range. (Incidentally, it is

    slightly misleading to say that neutrons interact preferen-

    tially with low-atomic-number materials). An analogous

    long chapter encompasses the breadth of industrial

    applications of articial tracers, including catalytic crack-

    ers, oileld recovery, blast-furnace linings and cylinder

    wear. Here, as with spectroscopy and other analytical

    techniques, microprocessors, visualization and data proces-

    sing have markedly inuenced the ways in which radio-

    nuclides can be employed over long periods, sometimes

    involving concurrent accumulation of data from many

    detectors, and with minimal human intervention. Flow rate

    measurements by several techniques are discussed here,

    with the application to uid dynamic...

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