Radioactivity and Radiation

Transcription

1 Radioactivity and Radiation

2 Radiation Protection c by Claus Grupen

3 Claus Grupen Mark Rodgers Radioactivity and Radiation What They Are, What They Do, and How to Harness Them 123

4 Claus Grupen Department of Physics University of Siegen Siegen Germany Mark Rodgers Bluesmith Information Systems Leeds UK ISBN ISBN (ebook) DOI / Library of Congress Control Number: Springer International Publishing Switzerland 2016 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. With cartoons by N. Downes, C. Grupen (partly inspired by his son Cornelius), L. Murchetz, V. Renčín, J. Wolter; copyright by the cartoonists. All line drawings, unless otherwise noted, are by C. Grupen, who retains the copyright for them. Certain diagrams were produced by M. Rodgers, who retains the copyright for them, using Jaxodraw by D. Binosi and L. Theußl, and the GNU Image Manipulation Program, Graphic design is by Armbrust Design, Stefan H. Armbrust, Siegen, Germany. Printed on acid-free paper This Springer imprint is published by Springer Nature The registered company is Springer International Publishing AG Switzerland

5 Disclaimer This book provides an overview of radiation physics. It is intended for members of the general public who are interested in radioactivity and radiation, and also science enthusiasts more generally. We have tried to keep the information correct and up-to-date. However, any reliance on such information is strictly at your own risk. This refers to the availability of the commercial products shown and also to those places where web sites are given. Web addresses can change quite rapidly, but we have made sure that the sites given in the text are available at the time of printing of this book. These web sites are not under our control. We have also tried to get written permission for the use of all pictures (relating to radiation detection, radiation instruments and other topics) which are shown in this book. Not in all cases did the companies providing such instruments or information respond to our request for permission to show their products. If any material in this book is being described or referred to improperly or incompletely, we would be grateful to be informed so that we can consider this for future editions of the book. Claus Grupen Mark Rodgers v

6 Preface Like taxes, radioactivity has long been with us and in increasing amounts; it is not to be hated and feared, but accepted and controlled. Radiation is dangerous, let there be no mistake about that but the modern world abounds in dangerous substances and situations too numerous to mention, Consider radiation as something to be treated with respect, avoided when practicable, and accepted when inevitable. Ralph Lapp Radiation is everywhere. In this book, we are concerned with ionising radiation, i.e. radiation that can ionise ordinary atoms, such as the rays which come from radioactive decay. Almost everything is radioactive. Radiation emerges from the soil, it is in the air, and our planet is continuously being bombarded with energetic cosmic radiation. Even the human body is radioactive: about 9000 decays of unstable nuclei occur per second in a normal human body. In the early days of the Earth, when our planet formed from the debris of the early solar system, the radiation level was much higher. It is possible that the origin, development and biodiversity of life have been positively influenced by ionising radiation. Since the early twentieth century, mankind has been able to artificially create radioactive nuclei: particularly so since the discovery of nuclear fission in the late 1930s. As early as 1905, Pierre Curie remarked that radium in the hands of criminals could be a disaster. Also, Louis de Broglie noted in his Nobel lecture in 1927 that he did not know whether science in the hands of humans is a good or a bad thing. The bombing of Hiroshima and Nagasaki in 1945 with nuclear weapons clearly demonstrated the disastrous effect of ionising radiation. The Nobel laureate for medicine, Maurice H.F. Wilkins, said contemplatively: We have now reached the point where it is an open question as to whether doing more science is a good thing. The nuclear accidents near Harrisburg at the Three Mile Island reactor (1979), in Chernobyl (1986), Tokaimura (1999) and Fukushima (2011) clearly demonstrated that nuclear fission requires high-quality safety systems. vii

7 viii Preface It is in the nature of humans to try to further our understanding of the world around us. No law will stop people undertaking research which might carry them into new domains, and there will always be a risk that a new technology will be misused. Therefore, it is important to understand the results of research and to explain the advantages and possible risks to everybody who is interested. There are of course great benefits to be gained from nuclear energy and ionising radiation, particularly in (fission) power plants and in nuclear medicine (both diagnosis and therapy). Also nuclear fusion, the energy source of the stars, may well solve all of mankind s energy problems in less than a century. The use and abuse of radiation concerns, among others, physicists, engineers, lawyers and healthcare professionals, as well as the general public. Everyone should be able to judge on the application of radioactivity in various fields himself without referring to experts. This book was originally published as a longer, more technical volume called Introduction to Radiation Protection. That book itself originated from a series of lectures that one of the authors (C.G.) gave over a period of more than 40 years. The text was first published in German by Vieweg and updated later in editions by Springer. It has also been translated into English and Japanese. A translation into Turkish is in preparation. This book would not have been possible without the help of a large number of people. In particular, the help of Dr. Tilo Stroh and Dr. Ulrich Werthenbach was invaluable in the creation of the earlier versions. We thank Dr. Cornelius Grupen for injecting ideas for the book, particularly on the structure of the material. In addition, M.R. would like to thank his wife Clare for her help and encouragement, and C.G. wants to thank his wife Heidemarie for her continuous support and patience. The aim of this more accessible book is to simplify the complicated physics and mathematics of the original version so that interested members of the public will be able to judge on possible dangers of ionising radiation. There is often an antipathy and distrust when ionising radiation is discussed. Occasionally this distrust is justified, especially when irresponsible discharges of radioactive waste into the environment are concerned. However, we are surrounded by radiation from many different sources, especially from the natural environment: the food that we eat and the air that we breathe are to a certain extent radioactive. This unavoidable radiation serves as a good starting point for comparison when discussing additional radiation from technical installations, and we can keep in mind that most of the additional radiation results from diagnostics and therapy in medicine. We have tried to make the field of radioactivity accessible to the layman with illustrations and examples that hopefully appeal to general experience. The aim of this book is to improve the understanding of the basics of radioactivity and to assess the radiation risks in comparison to the risks that we are used to taking every day without any consideration. Claus Grupen (Siegen, Germany) and Mark Rodgers (Leeds, UK), October 2016

8 Contents 1 Why Should I Read This Book? What Are Radioactivity and Radiation? Radioactivity Activity and Half-Life Radiation Doses Weighting Factors Avoiding Doses Summary Putting doses in context What Does Radiation Do? Interactions of Charged Particles Interactions of Neutrons Interactions of Photons Summary How Can We Make Radiation? Charged Particle Sources Photon Sources Neutron Sources Cosmic-Ray Sources Medical Applications Radioisotope Batteries Summary What Are X Rays? Medical X Rays X-Ray Crystallography Inspection and Quality Control Systems X Rays in Art Sources of Unwanted X Rays Summary ix

9 x Contents 6 Is Radioactivity Everywhere? Cosmic Rays Terrestrial Radiation Incorporation of Radioisotopes Radiation Exposures from Technical Installations Specific Environmental Exposures Exposures from Air Travel Exposures from Smoking Exposures from Water Questionable Applications in Medicine Summary What Does Radiation Do to Us? Early Effects Delayed Radiation Damage Genetic Damage Radiosensitivity Decorporation Non-Human Organisms Radiation-Absorbing Fungi Radiation Risk Factors Low Radiation Doses Eradication of Insect Pests Metabolism of Plutonium Summary How Can We Use Radioactivity Productively? Nuclear Fission Reactors Fusion Reactors Inertial Fusion Fusion by Magnetic Confinement The First Nuclear Reactor Natural Nuclear Reactors Summary How Can We Use Radioactivity Destructively? Summary What Happens When It Goes Wrong? Smaller-Scale Radiation Incidents Summary What About Non-Ionising Radiation? Microwaves Ultraviolet Light Lasers Summary

10 Contents xi 12 How Can We Stay Safe? Waste Storage Waste Transmutation Packaging and Transport Storage and Security of Radioactive Substances Handling of Unsealed Radioactive Sources Mitigating the Consequences of Accidents Arrangements for Fire Fighting Protection of Air, Water, and Soil Summary What Have We Learned? Appendices A How Can We Detect Radiation? A.1 Ionisation Chambers A.2 Proportional Counters A.3 Geiger-Müller Counters A.4 Solid-State Detectors A.5 Scintillators A.6 Neutron Counters A.7 Personal Dosimeters A.8 Accident Dosimetry A.9 Overview of Radiation Detector Types Summary B How is Radiation Protection Organised? B.1 National Regulations B.2 Radiation Protection Inside Organisations B.2.1 Licensing B.2.2 Bookkeeping B.2.3 Instruction and Training B.2.4 Medical Supervision B.2.5 Handling of Incidents B.2.6 Disposing of Radioactive Waste Summary C Periodic Table of Elements D Further Reading Glossary Index