Nuclear Fusion Power for Weapons Purposes

Abstract

Fusion reactors have the potential to be used for military purposes. This article provides quantitative estimates about weapon-relevant materials produced in future commercial fusion reactors and discusses how suitable such materials are for use in nuclear weapons. Whether states will consider such use in the future will depend on specific regulatory, political, economic, and technical boundary conditions. Based on expert interviews and the political science literature, we identify three of these conditions that could determine whether fusion power will have a military dimension in the second half of this century: first, the technological trajectory of global energy policies; second, the management of a peaceful power transition between rising and declining powers; and third, the overall acceptance of the nuclear normative order. Finally, the article discusses a few regulatory options that could be implemented by the time fusion reactors reach technological maturity and become commercially available; such research on fusion reactor safeguards should start as early as possible and accompany the current research on experimental fusion reactors.

KEYWORDS:

• Nuclear fusion
• nuclear proliferation
• safeguards
• tritium
• plutonium

ACKNOWLEDGMENTS

The authors thank Franz Fujara, Chris Lee-Gaston, Amanda Quinlan, Klaus Dieter Wolf, and two anonymous reviewers for their constructive feedback and useful comments on earlier drafts of this article.

Notes

1. A recent study commissioned by the European Union predicts market penetration around the year 2050 and does not exclude that fusion could account for up to 30 percent of electricity worldwide by the end of the century. Lawrence Livermore National Laboratory's Laser Inertial Fusion Energy project schedules the first commercial fusion plants in the 2030s. For the former, see Francesco Romanelli et al., “Fusion Electricity: A roadmap to the realisation of fusion energy,“ European Fusion Development Agreement, November 2012, <www.efda.org/wpcms/wp-content/uploads/2013/01/JG12.356-web.pdf?5c1bd2>; for the latter, see Lawrence Livermore National Laboratory, “Laser Inertial Fusion Energy,” <life.llnl.gov>. For a skeptical view, see Charles Seife, Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking (New York, NY: Viking Adult, 2008).

2. John P. Holdren et al., “Report of the Senior Committee on Environmental, Safety, and Economic Aspects of Magnetic Fusion Energy,” UCRL-53766 (Lawrence Livermore National Laboratory, September 1989); Jürgen Raeder, “Report on the European Safety and Environmental Assessment of Fusion Power (SEAFP),” Fusion Engineering and Design 29 (1995), pp. 121–40; I. Cook et al., “Safety and Environmental Impact of Fusion,” EFDA–S–RE-1 (European Fusion Development Agreement, April 2001).

3. Nuclear fusion requires either “magnetic confinement“ (MCF) or “inertial confinement“ (ICF) of the hot plasma fuel. MCF is widely seen as the dominant paradigm in attempts to produce electricity from nuclear fusion, whereas research on ICF is mainly carried out by national laboratories with a focus on nuclear weapon optimization and maintenance. See William J. Nuttall, Nuclear Renaissance: Technologies and Policies for the Future of Nuclear Power (New York, NY: Taylor & Francis Group, 2005), pp. 241–301. Historically, most studies on the possible military dimension of fusion reactors focused on ICF devices. Studies on military applications of MCF have come out only recently. See, for example, André Gsponer and Jean-Pierre Hurni, “ITER: The International Thermonuclear Experimental Reactor and the Nuclear Weapons Proliferation Implications of Thermonuclear Fusion Energy Systems,” Independent Scientific Research Institute, ISRI-04-01.17 (February 2, 2008); F. Faghihi, H. Havasi, and M. Amin-Mozafari, “Plutonium-239 Production Rate Study Using a Typical Fusion Reactor,” Annals of Nuclear Energy 35 (May, 2008), pp. 759–66; Fabian Sievert and Daniel Johnson, “Creating Suns on Earth: ITER, LIFE, and the Policy and Nonproliferation Implications of Nuclear Fusion Energy,” Nonproliferation Review 17 (July, 2010), pp. 323–46; A. Glaser and R. J. Goldston, “Proliferation Risks of Magnetic Fusion Energy: Clandestine Production, Covert Production and Breakout,” Nuclear Fusion 52 (April 2012), pp. 1–9.

4. Wolfgang Liebert and Jan C. Schmidt, “Towards a Prospective Technology Assessment: Challenges and Requirements for Technology Assessment in the Age of Technoscience,” Poiesis & Praxis 7 (June 2010), pp. 99–116.

5. Whereas ITER is built on the principle of MCF, laser-driven fusion plants are based on ICF. Although the ICF community has recently announced first-of-its-kind fusion plants for the late 2020s and commercial fusion power plants in the 2030s, most experts still assign magnetic confinement fusion a higher probability to succeed in commercial applications (Nuttall, Nuclear Renaissance, p. 289). Our analysis is therefore restricted to MCF designs, but most of our findings are applicable to ICF devices as well.

6. Dale Meade, “50 years of fusion research,” Nuclear Fusion 50 (2010), pp. 1–14.

7. D. Massonier et al., “A Conceptual Study of Commercial Fusion Power Plants: Final Report of the European Fusion Power Plant Conceptual Study (PPCS),” EFDA-RP-RE-5.0, (European Fusion Development Agreement, April 13, 2005).

8. Y. Chen et al., “The EU Power Plant Conceptual Study—Neutronic Design Analyses for Near Term and Advanced Reactor Models,” Forschungszentrum Karlsruhe GmbH, 2003, <http://bibliothek.fzk.de/zb/berichte/FZKA6763.pdf>.

9. Jörg Reckers, “Tritiumbilanzierung im Fusionsreaktor ITER: Anwendung statistischer Testtheorie auf Inspektionsstrategien bei Messunsicherheit” [Tritium Accountancy for the ITER Fusion Reactor: Application of Statistical Test Theory on Inspection Strategies with due Consideration of Measurement Uncertainty], Diploma Thesis, University of Hamburg, 2007.

10. By contrast, in a fission reactor, the longer the uranium is irradiated, the more plutonium isotopes are produced, which degrade the nuclear weapon performance. For details on the simulations, see Appendix C, note 1.

11. A comparison of plutonium production in fission and fusion reactors is given in Matthias Englert and Wolfgang Liebert, “Strong Neutron Sources, Is There an Exploitable Gap?,” paper delivered at the 51st Institute for Nuclear Materials Management Annual Meeting, Baltimore, Maryland, July 11–15, 2010.

12. In a fission reactor, the concentration of plutonium in the heavy metal mixture is typically several per mil for weapon grade plutonium (low burnup), and up to 1 percent for “civilian” reactor grade plutonium (higher burnups).

13. Romanelli, “A Roadmap to the Realisation of Fusion Energy,“ p. 5.

14. Indeed, the technical and economic hurdles for the use of fusion as an energy source remain high and could even prove prohibitive for the commercialization of this technology: major technical challenges lie in the confinement of the ultra-hot plasma inside the fusion reactor chamber, which must be assured for a sufficient amount of time for commercial reactor operations; in the material requirements for structural parts and reactor components, which have to withstand various forms of stresses (from radiological damage to high-energy neutron activation) unknown in fission reactors; and in nuclear waste handling needs, which still depend on materials not yet available. See also Michael Moyer, “Fusion's False Dawn,“ Scientific American 302 (March 2010), pp. 50–57; Sievert and Johnson, “Creating Suns on Earth,” pp. 331–35.

15. We polled 140 international experts on both nuclear fusion and nuclear proliferation with an email questionnaire in 2010 and received 22 answers and comments. Details of this Delphi study can be found at a dedicated website of the Interdisciplinary Research Group in Science, Technology and Security of the Darmstadt University of Technology, <www.ianus-tu-darmstadt.de/fusion>. Additionally, we held a number of small workshops with senior experts on the military dimension of nuclear fusion at Darmstadt University of Technology in 2011.

16. Scott D. Sagan, “The Causes of Nuclear Weapons Proliferation,” Annual Review of Political Science 14 (June 2011), pp. 225–44.

17. William C. Potter with Gaukhar Mukhatzhanova, eds., Forecasting Nuclear Proliferation in the 21st Century, Volume 1: The Role of Theory (Stanford, CA: Stanford University Press); William C. Potter with Gaukhar Mukhatzhanova, eds., Forecasting Nuclear Proliferation in the 21st Century, Volume 2: A Comparative Perspective (Stanford, CA: Stanford University Press).

18. Matthew Fuhrmann, “Spreading Temptation: Proliferation and Peaceful Nuclear Cooperation Agreements,” International Security 34 (Summer 2009), pp. 7–41.

19. For a critical appraisal of Fuhrmann's hypothesis, see Christoph Bluth et al., “Correspondence: Civilian Nuclear Cooperation and the Proliferation of Nuclear Weapons,“ International Security 35 (Summer 2010), pp. 184–200.

20. Matthew Kroenig, ”Importing the Bomb: Sensitive Nuclear Assistance and Nuclear Proliferation,” Journal of Conflict Resolution 53 (April 2009), pp. 161–80.

21. Itty Abraham, “The Ambivalence of Nuclear Histories,” Osiris 21 (2006), pp. 49–65.

22. The chances that selected states might operate only fusion reactors are not so remote: Italy abandoned its nuclear program in the 1980s, and Germany and Switzerland are currently phasing out (fission) nuclear power. As all three countries are heavily involved in the ITER research project, it is not excluded that they might re-enter the nuclear energy club once commercial fusion reactors become available on the market.

23. For exact figures, see International Panel on Fissile Materials, “Global Fissile Material Report 2011: Nuclear Weapons and Fissile Material Stockpile and Productions,” (IPFM, 2011), and Hans M. Kristensen and Robert S. Norris, “Global nuclear weapons inventories, 1945–2013,” Bulletin of the Atomic Scientists 69 (September/October 2013), pp. 75–81, <http://bos.sagepub.com/content/69/5/75.full.pdf + html>. Strategic parity does not necessarily mean numerical parity in weapons and material stocks, and leading realists emphasize the potential to achieve nuclear parity with small arsenals possessing secure second-strike capabilities. At the same time, strategic analysts are observing growing US efforts to achieve nuclear primacy vis-à-vis Washington's nuclear competitors, see Keir A. Lieber and Daryl G. Press, “The Rise of U.S. Nuclear Primacy,” Foreign Affairs (March/April 2006), pp. 42–54. While this primacy could be maintained “for a decade or more” vis-à-vis China, realists would warn that Beijing will have no other choice than to improve its nuclear capabilities both qualitatively and quantitatively in the future (ibid); and that China's strong economic growth will give Beijing's strategic planners the means to reduce these vulnerabilities soon.

24. Note that current Indian weapon-grade plutonium production amounts does not exceed 20–25 kg per year; see “Dhruva Research Reactor,” Nuclear Threat Initiative, September 1, 2003, <www.nti.org/facilities/837/>; our conservative estimate suggests that a fusion reactor could breed more than ten times this amount of plutonium.

25. On China's current policy of nuclear restraint, see Lora Saalman, “Placing a Renminbi Sign on Strategic Stability and Nuclear Reductions,“ in Elbridge A. Colby and Michael S. Gerson, eds., Strategic Stability: Contending Interpretations (Strategic Studies Institute and U.S. Army War College Press, 2013), pp. 343–81.

26. On the issue of underbalancing, see Keir A. Lieber and Gerard Alexander, “Waiting for Balancing: Why the World is Not Pushing Back,“ International Security 30 (Summer 2005), pp. 109–39. On the projected timelines for the global power transition, see the economic growth forecasts published by Goldman Sachs, HSBC, Price Waterhouse Cooper, and CitiGroup. While the United States is still the leading economy today, all major forecasts agree that it will lose its economic primacy to China or to India (or both) by 2050. For an overview over these forecasts, see Witold Kwasnicki, “China, India and the Future of the Global Economy,” MPRA Paper 3255, July 25, 2011, <http://mpra.ub.uni-muenchen.de/32558/1/MPRA_paper_32558.pdf>.

27. For the strategic triangle of Washington-Tokyo-Beijing, see Michael D. Swaine et al., China's Military and the US-Japan Alliance in 2030: A Strategic Net Assessment (Washington, DC: Carnegie Endowment of International Peace, 2013).

28. Harald Müller and Andreas Schmidt, “The Little-Known Story of Deproliferation: Why States Give Up Nuclear Weapons Activities,” in Potter and Mukhatzhanova, Forecasting Nuclear Proliferation in the 21st Century, Volume 1: The Role of Theory, pp. 124–58.

29. William C. Potter, “The NPT & the Sources of Nuclear Restraint,” Daedalus 139 (Winter 2010), pp. 68–81.

30. See Appendix C, note 3.

31. Ed Gerstner, “Nuclear Energy: The hybrid returns,” Nature 460 (July 2, 2009), pp. 25–28.

32. It is advisable to safeguard also larger experimental reactors. In two decades, several national DEMO reactors might go online in various ITER countries. These reactors will offer relevant plutonium production and tritium diversion potentials.

33. Formally, safeguards are not foreseen for fusion reactors, at this stage. The main reason is legalistic, i.e. a fusion reactor—according to the IAEA guidelines—would not fall under the term “facility” and is therefore not subject to IAEA safeguards, since it is neither a “reactor” (defined by a nuclear chain reaction), nor a “critical facility,” nor a location where nuclear material in quantities more than an effective kilogram is customarily used. See International Atomic Energy Agency, “The Structure and Contents of Agreements Between the Agency and States Required in Connection with the Treaty on the Non-Proliferation of Nuclear Weapons,” INFCIRC/153 (Corrected), June 1972.

1. The EFDA study discusses four promising commercial power plant concepts termed “Power Plant Conceptual Study” (PPCS) A, B, C, and D, respectively. While the reactor concept A relies partly on “established” materials and technologies used in the commercial fission reactor industry today and is 735 therefore closer to possible realization, concepts B, C, and D are technologically more demanding and will require considerably more R&D effort. Assuming that the first commercial fusion power reactors will be built on the basis of the “simpler” PPCS-A model, the only design considered here and the basis for all numerical simulations presented in this article is concept A.

1. For an overview, see Martin Kalinowski, International Control of Tritium for Nuclear Nonproliferation and 740 Disarmament (Boca Raton: CRC Press, 2004).

1. All neutronic simulations reported in this article were carried out by using the Monte Carlo N-Particle Transport Code (MCNP), D. Pelowitz, MCNPX User's Manual Version 2.7.0, LA-CP-11-00438 (2011). Burnup calculations were carried out using MCMATH developed at the IANUS Institute of Darmstadt University of Technology and VESTA, W. Haeck, VESTA User's Manual, IRSN Report, DSU/SEC/T/2008-331 –745 Index A (2009).

2. For technical details on the neutronic simulations, please refer to documents and papers available at the Interdisciplinary Research Group in Science, Technology and Security website, <www.ianus.tudarmstadt.de/fusion>, especially Matthias Englert, Giorgio Franceschini, and Wolfgang Liebert, “Strong Neutron Sources—How to cope with weapon material production capabilities of fusion and spallation 750 neutron sources,” Paper delivered at the European Safeguards Research and Development Association/Institute for Nuclear Materials Management Annual Meeting, Aix-en-Provence, France, October 16–20, 2011.

3. First, a fraction of the uranium will fission when exposed to the high-energy neutrons coming from the plasma. A fusion reactor such as PPCS-A with a nominal thermal power of 5.5 gigawatts can 755 certainly handle a limited amount of surplus heat, so we assumed that 10 percent of the “excess heat” in some blankets of the reactor would not compromise the safe operation of the reactor. Under these rather conservative assumptions, our simulations suggest that a proliferator could not load all the blankets with 10 percent uranium, as this would overheat the machine. Still, an overall 1 percent uranium load factor would allow safe operation of the reactor. Second, the introduction of uranium 760 into a blanket automatically reduces the amount of lead-lithium within the module. Because lithium is necessary to breed tritium—one of the reactor fuels—an excessive amount of uranium in the blankets would deplete the lithium and hence the (tritium) fuel supply of the machine. Nevertheless, since tritium is as volatile as hydrogen and decays radioactively, a fusion reactor is always designed to produce more tritium than it consumes. Therefore, by replacing only 1 percent of the lead-lithium 765 alloy with fertile material, the steady tritium supply to the plasma reaction chamber would still be guaranteed. Measuring overall tritium production might be also an interesting safeguard measure, since a deviation from the expected tritium production might allow detecting a diversion of neutrons from tritium production.

1. Glaser and Goldston, “Proliferation risks of magnetic fusion energy,” pp. 1–9.

2. Reckers, “Tritiumbilanzierung im Fusionsreaktor ITER.”