The Quest for a Fusion Energy Reactor This page intentionally left blank The Quest for a Fusion Energy Reactor An Insider’s Account of the INTOR Workshop Weston M. Stacey 1 2010 3 Oxford University Press, Inc., publishes works that further Oxford University’s objective of excellence in research, scholarship, and education. Oxford New York Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi New Delhi Shanghai Taipei Toronto With offi ces in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan Poland Portugal Singapore South Korea Switzerland Thailand Turkey Ukraine Vietnam Copyright © 2010 by Oxford University Press, Inc. Published by Oxford University Press, Inc. 198 Madison Avenue, New York, New York 10016 www.oup.com Oxford is a registered trademark of Oxford University Press All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of Oxford University Press. Library of Congress Cataloging-in-Publication Data Stacey, Weston M. The quest for a fusion energy reactor : an insider’s account of the INTOR Workshop / Weston M. Stacey. p. cm. Includes bibliographical references and index. ISBN 978-0-19-973384-2 1. Fusion reactors—Design and construction. 2. Engineering test reactors—Design and construction. 3. Tokamaks. 4. Fusion reactors— Research—International coorporation. 5. International Tokamak Reactor Workshop I. Title. TK9204.S62 2010 621.48’4—dc22 2009022620 987654321 Printed in the United States of America on acid-free paper To all of those who contributed to the INTOR Workshop. This page intentionally left blank Acknowledgments This book is in large part an account of scientifi c and technological information being collected, evaluated, and integrated into a design concept for a fusion reactor that was then analyzed in detail. Prob- ably more than a thousand scientists and engineers in Europe, Japan, the USA, and the USSR were involved in this process, and the actual development of the underlying experimental data and theoretical concepts involved thousands of other scientists and engineers world- wide over a much longer period. The contributions of only a few hundred of these people who were the most active participants in the INTOR Workshop activities or leading the various government fusion programs during 1978–88 are recognized in this book, but without the work of the many other scientists and engineers who developed the basic information, the work of the INTOR Workshop could not have been carried out. Several people have been instrumental in the production of the book. Phyllis Cohen, physics editor for Oxford University Press, had the insight to recognize the important story that was being told in a somewhat unconventional manner from reading a draft of the fi rst chapters and has offered valuable advice on producing a fi nal version of the book, particularly in choosing an informative title and by securing knowledgeable reviews of the manuscript with good sugges- tions for its improvement. Phyllis has also provided the essential guidance of the book through the production process. Trish Watson’s copy editing was most helpful both in eliminating inconsistencies and improving syntax. viii acknowledgments On the home front, Valarie Spradling has provided essential administrative support in producing electronic versions of drawings and photographs and in coordinating the transmission of the fi les involved in the production of this book. Finally, Drs. John Porter and Lucy Axtell provided comments on a draft of the fi rst two chap- ters, which led to changes that make the material more accessible to the nonscientist reader. Contents 1 Prologue (1978) 3 2 Zero Phase of the INTOR Workshop (1978–80) 17 3 Phase 1 of the INTOR Workshop (1980 –81) 65 4 Phase 2A of the INTOR Workshop (1981–88) 109 5 Epilogue 157 Appendices A Sessions of the INTOR Workshop 161 B INTOR Workshop Participants and Experts 163 C Reports of the INTOR Workshop 169 D Tokamaks in the World 173 E Awards to the Author for the INTOR Workshop 179 Glossary 181 Bibliography of Offi cial INTOR Workshop Publications 187 This page intentionally left blank The Quest for a Fusion Energy Reactor This page intentionally left blank 1 Prologue (1978) The multibillion dollar International Thermonuclear Experimental Reactor (ITER), for which construction began in 2009 following many years of research, development, design, and negotiation, is both a major step toward harnessing mankind’s ultimate energy source, nuclear fusion, and an ambitious step toward bringing the nations of the world together to address a common challenge of our joint future—energy. The governments collaborating on ITER (the EU, Japan, Russia, the USA, Korea, China, India) represent more than half the population of the world. The present ITER project has its origins in the INTOR Work- shop (1978–88) in which fusion scientists and engineers from the European Community (EC), Japan, the USA, and the USSR joined together to assess the readiness of the world’s fusion programs to undertake the design and construction of the fi rst experimental fusion energy reactor, to defi ne the research and development that would be necessary to do so, to develop a design concept for such a device, and to identify and analyze critical technical issues that would have to be overcome. It was on the basis of the positive results of the INTOR Workshop that Secretary Gorbachev made the recommen- dation to President Reagan at the 1985 Geneva summit that led to the formation of the ITER project. In 1988 I wrote a scientifi c/technical summary of the INTOR Workshop (Progress in Nuclear Energy, vol. 11, p. 119, 1988). Now, twenty years later, perhaps enough time has passed to put into perspective the broader history of the INTOR Workshop and its role leading to the creation of the ITER project to build the fi rst fusion 3 4 the quest for a fusion energy reactor energy reactor. This book is based on the working journal that I kept during the decade that I was the vice chairman of the INTOR Workshop, recording both the internal workings of the workshop and its external interactions with governmental bodies searching fi tfully for the mechanisms of international cooperation. Some explanatory material is included to make both fusion and the history of the tortured path leading to the creation of a major international scientifi c project accessible to nonspecialists. Energy Resources and the Rationale for Fusion Development Nuclear fusion will almost surely become mankind’s ultimate source of energy, because of the essentially limitless fuel source. One in every 10,000 water molecules contains an atom of the heavy form of hydrogen known as deuterium (D), so the oceanic fuel source for D+D fusion is essentially unlimited. However, fusion of D+D requires much higher temperatures to achieve the same fusion rate that can be achieved at lower (hence less diffi cult to achieve) temper- atures by the fusion of deuterium with an even heavier form of hydrogen known at tritium (T). Since tritium is radioactive with a half-life of about 12 years, it does not exist in nature, but it can be made by neutron capture in the nucleus of lithium atoms. Because the products of the D+T fusion reaction are a helium nucleus and a neutron, the neutron produced by the fusion reaction can, in prin- ciple, be captured in lithium surrounding the fusion chamber to produce another T to replace the one destroyed in the fusion reac- tion, thus providing a self-suffi cient fuel cycle for producing and using the tritium. Because some of the neutrons produced by fusion will be captured in other materials or will leak from the system, and because some of the tritium will radioactively decay away before it can be used, it actually is necessary to have a few extra neutrons in order to produce enough tritium to make the D+T fusion fuel cycle self- suffi cient. In this case, nature is benefi cent in providing some mate- rials (e.g., lead, beryllium) that, when they capture a neutron, emit two or three new neutrons. This neutron multiplication makes a prologue (1978) 5 self-suffi cient D+T fusion fuel cycle possible. Thus, the ultimate, or limiting, fuel source for the D+T fusion reaction is lithium, and there is a lot of it. The best estimate that I know is that there is enough lithium to enable D+T fusion to provide all the electricity needed in the world for more than 6,000 years (at the estimated 2050 electricity usage rate). This seems to be a pretty good argument that the fuel source for fusion is “essentially unlimited.” The question of when fusion energy will be needed is much more complex. Most of the world’s energy today is produced from carbon-based “fossil” fuels (coal, oil, gas, etc.). Even though the extent of these resources and the practicality and economics of their extraction (e.g., oil from tar sands) are still debated by “experts” and others, there are clearly limits on the remaining fossil fuel resources, and there is a substantial body of opinion that practical limits will be reached in the present century. It is also clear that there are adverse environmental effects both of extracting fossil fuels from the earth and of releasing carbon and sulfur into the atmosphere by burning them, so environmental limits on fossil fuels may be closer at hand than resource limits. The most likely alternative to burning fossil fuel to produce energy, the nuclear fi ssion of uranium, presently provides about 15 % of the world’s electricity, and there are strong indications that produc- tion will increase signifi cantly in the coming decades.