DOI:10.13140/2.1.2757.9683 THE LONG-TERM NUCLEAR EXPLOSIVES PREDICAMENT THE FINAL DISPOSAL OF MILITARILY USABLE FISSILE MATERIAL IN NUCLEAR WASTE FROM NUCLEAR POWER AND FROM THE ELIMINATION OF NUCLEAR WEAPONS Johan Swahn Technical Peace Research Group Institute of Physical Resource Theory Göteborg 1992 [Blank Page] THE LONG-TERM NUCLEAR EXPLOSIVES PREDICAMENT THE FINAL DISPOSAL OF MILITARILY USABLE FISSILE MATERIAL IN NUCLEAR WASTE FROM NUCLEAR POWER AND FROM THE ELIMINATION OF NUCLEAR WEAPONS Johan Swahn Technical Peace Research Group Institute of Physical Resource Theory Göteborg 1992 ISBN 91-7032-689-4 Chalmers Tekniska Högskola Bibliotekets Reproservice Göteborg 1992 UTAN TVIVEL ÄR MAN INTE KLOK Tage Danielsson (1928-1985) [Blank Page] THE LONG-TERM NUCLEAR EXPLOSIVES PREDICAMENT THE FINAL DISPOSAL OF MILITARILY USABLE FISSILE MATERIAL IN NUCLEAR WASTE FROM NUCLEAR POWER AND FROM THE ELIMINATION OF NUCLEAR WEAPONS Johan Swahn Technical Peace Research Group Institute of Physical Resource Theory Chalmers University of Technology S-412 96 Göteborg, Sweden ABSTRACT It is possible that the long-term global energy future does not turn out to be a breeder-reactor-based plutonium economy, but that a sustainable energy future based on renewable energy sources develops instead, i.e., a post-nuclear world. The thesis is based on a scenario where this is the case. Then large amounts of fissile material, that would otherwise to be consumed in the plutonium economy, will have to be disposed of as long-lived nuclear waste. This material is usable for the construction of nuclear explosives and consists of weapons-grade uranium and weapons-grade plutonium from nuclear weapons dismantled as a result of reductions of the nuclear arsenals, and reactor-grade plutonium produced in civil nuclear reactors, but not recycled. Regarding the possibilities of using reactor-grade plutonium for the construction of nuclear explosives, it is found that reactor-grade plutonium is an entirely credible fissile material for nuclear explosives, but that the increased spontaneous fission neutron background inherent in such material does provide an incentive for a nuclear explosives program to produce weapons-grade plutonium. On the other hand, laser isotope separation technology can be used to convert reactor- grade plutonium into weapons-grade plutonium. Present planning for the final disposal of spent nuclear reactor fuel that contains reactor-grade plutonium calls for the deposition of the material in mined geologic repositories. This disposal solution does, however, not make the fissile material “practicably irrecoverable” and safeguards would have to be put on the material for an indefinite time-period. Thus our generations, who utilize nuclear power, will leave a burden on future generations that do not. This is the long-term nuclear explosives predicament. In this thesis the predicament is examined. A scenario is described where the production of new military fissile material is halted and where civil nuclear power is phased out in a “no-new orders” case. It is found that approximately 1 100 tonnes of weapons-grade uranium, 233 tonnes of weapons-grade plutonium and 3 795 tonnes of reactor-grade plutonium has to be finally disposed of as nuclear waste, as the use of large-scale nuclear technology is phased out. This material could be used for the construction of over 1 million nuclear explosives and will be available for such purposes for a very long time. Reactor-grade plutonium is found to be easier to extract from spent nuclear fuel with time and some physical characteristics important for the construction of nuclear explosives are improved. However, the biggest problem, the large spontaneous neutron background, does not decrease. Alternative methods for disposal of the fissile material that will avoid the long- term nuclear explosives predicament are examined. Among these methods are dilution, denaturing or transmutation of the fissile material and options for practicably irrecoverable disposal in deep boreholes, on the sea-bed, and in space. Weighing in costs, environmental safety and public acceptance it is found that the deep boreholes method for disposal should be the primary alternative to be examined further. This method, which may make the fissile material more difficult to retrieve than from a mined repository, can be combined with an effort to “forget” where the material was put. This would, however, be a reversal of the present considerations where an attempt is planned to transfer as much information about the nuclear waste as possible into the future. Included in the thesis is also an evaluation of the possibilities of controlling the limited civil nuclear activities in a post-nuclear world. It is found that the opportunities for an effective safeguard regime are very favourable. Some surveillance technologies that might find widespread use in a post-nuclear world are described, including satellite surveillance. In a review part of the thesis, methods for the production of fissile material usable for the construction of nuclear explosives are described; the technological basis for the construction of nuclear weapons is examined, including the possibilities for using reactor-grade plutonium produced in civil nuclear power reactors for such purposes; also the present planning for the disposal of spent fuel from civil nuclear power reactors and for the handling of the fissile material from dismantled nuclear warheads is described. The Swedish plan for the handling and disposal of spent nuclear fuel is selected as a reference example of a spent fuel disposal system and is described in detail. Keywords: nuclear explosives, nuclear weapons, construction, destruction, high- level nuclear waste, spent nuclear fuel, disposal, long-term, ethics, Swedish, fissile material, plutonium, production, transmutation, nuclear fuel cycle, military, laser isotope separation, sustainable energy future, sustainability, plutonium economy PREFACE This thesis is the first presented within the research field of technical peace research at the Chalmers University of Technology. The research field was established in 1987, on a trial basis, under the auspices of the Technical Faculty at Chalmers. The thesis is, of course, my personal responsibility, but it does owe its existence also to many persons who have directly or indirectly been supportive in the process of its creation. I would like to especially acknowledge the following individuals or groups: • Victor Weisskopf, who led a seminar on the threat of the nuclear arms race at the 1982 CERN Summer School, and who awoke my interest in the subject. • The founders of the Swedish Society of Engineers for the Prevention of Nuclear War [Föreningen Svenska Ingenjörer mot Kärnvapen] for their indirect role in the early 1980’s in creating an openness to proposals for the academic study of the technical aspects of armaments and disarmament at the Chalmers. • Professor Karl-Erik Eriksson who made the original proposal that technical peace research should be carried out at Chalmers, and professor Tor Kihlman who helped realize the proposal. • The Ministry of Foreign Affairs who came up with the original seed funding. • The Steering Group for Technical Peace Research [Ledningsgruppen för teknisk fredsforskning] who guided me throughout the process. • The Swedish Council for Planning and Coordination of Research [Forsknings- rådsnämnden] for their funding. • My colleagues at the Institute of Physical Resource Theory, who have created a unique research atmosphere that gave me support in an otherwise sometimes lonely endeavour. • Karl-Erik Eriksson, my supervisor, for the time and support he gave. • Josie Stein and Stellan Welin who made an effort to finally get me started. • Those who found time to read and comment drafts to the thesis, and especially Karl-Erik, Gudmar Grosshög and Stellan Welin. • The library staff, and especially Sickan, who never tired in their efforts to help me with difficult requests. • Linus and Patrik for their help with the image processing of the satellite imagery. • The Ministry of Foreign Affairs for the funding of the satellite images. • Ulf Heikki at Satellitbild for his helpfulness and kind hospitality. • Apple Computer for bringing us System 7 and the Powerbook. • And, all those others, none named, none forgotten, who supported me throughout the years with inspiration, help and advice. For those readers that do not master the Swedish language, let me say a few words about the citation at the front of the thesis. The meaning of the quote is twofold. It can be translated as “Without scepticism, one is not wise“, but also as “One is, without doubt, insane“. Tage Danielsson was a brilliant humoristic humanist whose subtle but biting reflections ceased at a moment in history when perhaps they are needed most. I want to thank my parents and family and friends for their support and finally, I want to extend my deep love and gratitude to my wife, Eva Eiderström, whose patience was unending, to my eldest son Linus who could understand and sometimes PREFACE ii PREFACE accept that his father had a “book“ to write, and to my youngest son Hampus, who was steadfast company in the final stages of the writing. Göteborg, April 12th, 1992, Johan Swahn COMMENTS TO THE SECOND PRINTING Corrections of errors that I have found in the first printing have been made. The only correction that I feel important enough to mention specifically is the previously incorrect use of the fissile plutonium production instead