Nuclear Fission Reactors James A. Mahaffey, Ph.D. NNPP__FFiissssiioonnRReeaaccttoorr__44PP..iinndddd ii 99//11//1111 1111::0088 AAMM For Michael Thomas Fletcher NUCLEAR FISSION REACTORS Copyright © 2012 by James A. Mahaffey, Ph.D. All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher. For information contact: Facts On File, Inc. An imprint of Infobase Learning 132 West 31st Street New York NY 10001 Library of Congress Cataloging-in-Publication Data Mahaffey, James A. Nuclear fission reactors / James A. Mahaffey. p. cm.—(Nuclear power) Includes bibliographical references and index. ISBN 978-0-8160-7651-2 (hardcover: alk. paper) ISBN 978-1-4381-3814-5 (e-book) 1. Nuclear reactors—Juvenile literature. 2. Nuclear fission—Juvenile literature. I. Title. TK9148.M323 2011 621.48'3—dc22 2010053705 Facts On File books are available at special discounts when purchased in bulk quantities for businesses, associations, institutions, or sales promotions. Please call our Special Sales Department in New York at (212) 967-8800 or (800) 322-8755. You can find Facts On File on the World Wide Web at http://www.infobaselearning.com Excerpts included herewith have been reprinted by permission of the copyright holders; the author has made every effort to contact copyright holders. The publishers will be glad to rectify, in future editions, any errors or omissions brought to their notice. Text design by Annie O’Donnell Composition by Julie Adams Illustrations by Bobbi McCutcheon Photo research by Suzanne M. Tibor Cover printed by Bang Printing, Brainerd, Minn. Book printed and bound by Bang Printing, Brainerd, Minn. Date printed: October 2011 Printed in the United States of America 10 9 8 7 6 5 4 3 2 1 This book is printed on acid-free paper. Contents Preface vii Acknowledgments x Introduction xi 1 The Nuclear Fission Process 1 Fissionable and Fissile Nuclides 2 Energy-Dependent Nuclear Reactions 4 Th e Chain Reaction 5 Th e Delicate Balance of Neutron Gain and Loss 7 Th e Mousetrap Analogy 8 2 How to Make Energy with Nuclear Fission 10 Th e Th ermal Reactor and the Use of a Moderator 11 Th e Advantages and Disadvantages of Graphite 14 Th e Fast Reactor and Fuel Breeding 16 3 Controlling Nuclear Fission 21 Th e Dynamics of Nuclear Fission 21 Neutron Poisons 24 Fission Th at Controls Itself 26 Nonpoisonous Controls 29 Bio-shielding 30 4 Transferring Heat and Keeping Things from Melting 33 Liquid Cooling 34 Gas Cooling 35 Unusual Reactor Cooling Strategies 36 Looped Cooling Systems 36 Th e Ultimate Heat Sink 39 Emergency Core Cooling Systems 41 NNPP__FFiissssiioonnRReeaaccttoorr__44PP..iinndddd iiiiii 99//11//1111 1111::0088 AAMM 5 The Many Ways to Build a Power Plant 43 Th e Pressurized Water Reactor 44 Th e Boiling Water Reactor 51 Th e Gas-Cooled Reactor 54 Reactor Designs Th at Are Not Used for Commercial Power 54 Th e Liquid Metal–Cooled Reactor 59 6 Nonnuclear Components of a Power Plant 63 Instruments and Controls 64 Th e Retro Design of a Nuclear Plant 68 Explosion Containment Strategies 70 Backup Generators 73 Steam Turbines 74 Generators 76 Th e Switch and Transformer Yard 77 7 A Walk through a Nuclear Power Plant 80 Th reading through the Security Maze 82 Whole-Body Radiation Measurement 85 Th e Control Room 88 Standing on the Core Plate in a Boiling Water Reactor 90 Reactor Start-up 91 Fuel Management 95 Suiting Up for Maintenance Procedures 100 8 Environmental Advantages, Disadvantages, and Economics 103 Air Pollution 105 An Odd Reactor Experiment in Georgia 108 Th ermal Pollution 110 Fuel Availability 112 Fuel Reprocessing 115 Th e Cost of Nuclear Power 117 NNPP__FFiissssiioonnRReeaaccttoorr__44PP..iinndddd iivv 99//11//1111 1111::0088 AAMM Conclusion 122 Chronology 128 Glossary 131 Further Resources 136 Index 139 NNPP__FFiissssiioonnRReeaaccttoorr__44PP..iinndddd vv 99//11//1111 1111::0088 AAMM NNPP__FFiissssiioonnRReeaaccttoorr__44PP..iinndddd vvii 99//11//1111 1111::0088 AAMM Preface Nuclear Power is a multivolume set that explores the inner workings, his- tory, science, global politics, future hopes, triumphs, and disasters of an industry that was, in a sense, born backward. Nuclear technology may be unique among the great technical achievements, in that its greatest moments of discovery and advancement were kept hidden from all except those most closely involved in the complex and sophisticated experimen- tal work related to it. Th e public fi rst became aware of nuclear energy at the end of World War II, when the United States brought the hostilities in the Pacifi c to an abrupt end by destroying two Japanese cities with atomic weapons. Th is was a practical demonstration of a newly developed source of intensely concentrated power. To have wiped out two cities with only two bombs was unique in human experience. Th e entire world was stunned by the implications, and the specter of nuclear annihilation has not entirely subsided in the 60 years since Hiroshima and Nagasaki. Th e introduction of nuclear power was unusual in that it began with specialized explosives rather than small demonstrations of electrical- generating plants, for example. In any similar industry, this new, intrigu- ing source of potential power would have been developed in academic and then industrial laboratories, fi rst as a series of theories, then incremental experiments, graduating to small-scale demonstrations, and, fi nally, with fi nancial support from some forward-looking industrial fi rms, an advan- tageous, alternate form of energy production having an established place in the industrial world. Th is was not the case for the nuclear industry. Th e relevant theories required too much eff ort in an area that was too risky for the usual industrial investment, and the full engagement and commitment of governments was necessary, with military implications for all develop- ments. Th e future, which could be accurately predicted to involve nuclear power, arrived too soon, before humankind was convinced that renewable energy was needed. Aft er many thousands of years of burning things as fuel, it was a hard habit to shake. Nuclear technology was never developed with public participation, and the atmosphere of secrecy and danger sur- rounding it eventually led to distrust and distortion. Th e nuclear power industry exists today, benefi ting civilization with a respectable percentage vii NNPP__FFiissssiioonnRReeaaccttoorr__44PP..iinndddd vviiii 99//11//1111 1111::0088 AAMM viii NUCLEAR FISSION REACTORS of the total energy supply, despite the unusual lack of understanding and general knowledge among people who tap into it. Th is set is designed to address the problems of public perception of nuclear power and to instill interest and arouse curiosity for this branch of technology. Th e History of Nuclear Power, the fi rst volume in the set, explains how a full understanding of matter and energy developed as sci- ence emerged and developed. It was only logical that eventually an atomic theory of matter would emerge, and from that a nuclear theory of atoms would be elucidated. Once matter was understood, it was discovered that it could be destroyed and converted directly into energy. From there it was a downhill struggle to capture the energy and direct it to useful purposes. Nuclear Accidents and Disasters, the second book in the set, concerns the long period of lessons learned in the emergent nuclear industry. It was a new way of doing things, and a great deal of learning by accident analy- sis was inevitable. Th ese lessons were expensive but well learned, and the body of knowledge gained now results in one of the safest industries on Earth. Radiation, the third volume in the set, covers radiation, its long- term and short-term eff ects, and the ways that humankind is aff ected by and protected from it. One of the great public concerns about nuclear power is the collateral eff ect of radiation, and full knowledge of this will be essential for living in a world powered by nuclear means. Nuclear Fission Reactors, the fourth book in this set, gives a detailed examination of a typical nuclear power plant of the type that now pro- vides 20 percent of the electrical energy in the United States. Fusion, the fi ft h book, covers nuclear fusion, the power source of the universe. Fusion is oft en overlooked in discussions of nuclear power, but it has great poten- tial as a long-term source of electrical energy. Th e Future of Nuclear Power, the fi nal book in the set, surveys all that is possible in the world of nuclear technology, from spacefl ights beyond the solar system to power systems that have the potential to light the Earth aft er the Sun has burned out. At the Georgia Institute of Technology, I earned a bachelor of science degree in physics, a master of science, and a doctorate in nuclear engi- neering. I remained there for more than 30 years, gaining experience in scientifi c and engineering research in many fi elds of technology, includ- ing nuclear power. Sitting at the control console of a nuclear reactor, I have cold-started the fi ssion process many times, run the reactor at power, and shut it down. Once, I stood atop a reactor core. I also stood on the bottom core plate of a reactor in construction, and on occasion I watched the eerie blue glow at the heart of a reactor running at full power. I did some time NNPP__FFiissssiioonnRReeaaccttoorr__44PP..iinndddd vviiiiii 99//11//1111 1111::0088 AAMM Preface ix in a radiation suit, waved the Geiger counter probe, and spent many days and nights counting neutrons. As a student of nuclear technology, I bring a near-complete view of this, from theories to daily operation of a power plant. Notes and apparatus from my nuclear fusion research have been requested by and given to the National Museum of American History of the Smithsonian Institution. My friends, superiors, and competitors for research funds were people who served on the USS Nautilus nuclear sub- marine, those who assembled the early atomic bombs, and those who were there when nuclear power was born. I knew to listen to their tales. Th e Nuclear Power set is written for those who are facing a growing world population with fewer resources and an increasingly fragile envi- ronment. A deep understanding of physics, mathematics, or the special- ized vocabulary of nuclear technology is not necessary to read the books in this series and grasp what is going on in this important branch of science. It is hoped that you can understand the problems, meet the challenges, and be ready for the future with the information in these books. Each volume in the set includes an index, a chronology of important events, and a glossary of scientifi c terms. A list of books and Internet resources for further information provides the young reader with additional means to investigate every topic, as the study of nuclear technology expands to touch every aspect of the technical world. NNPP__FFiissssiioonnRReeaaccttoorr__44PP..iinndddd iixx 99//11//1111 1111::0088 AAMM