Replacing Highly Enriched Uranium in Naval Reactors
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NTI Paper MARCH 2016 Replacing Highly Enriched Uranium in Naval Reactors SUMMARY Highly enriched uranium (HEU) is the simplest nuclear material to use for an improvised nuclear device, making it a target for terrorist groups seeking to inflict mass destruction. This paper examines the current status of HEU in naval propulsion programs worldwide, with a specific focus on the U.S. Navy’s program. It includes a technical assessment of less risky low-enriched uranium (LEU) alternatives and recommendations to enable conversion to such alternate technologies. George M. Moore, Cervando A. Banuelos, and Thomas T. Gray This paper was made possible by a grant from the Nuclear Threat Initiative. George M. Moore, PhD, JD is a Scientist-in-Residence at the James Martin Center for Nonproliferation Studies (CNS) of the Middlebury Institute of International Studies at Monterey (MIIS), a Graduate School of Middlebury College. Cervando A. Banuelos received his M.A. in Nonproliferation and Terrorism Studies from MIIS in 2015. Thomas T. Gray received his M.A. in Nonproliferation and Terrorism Studies from MIIS in 2015. About the Nuclear Threat Initiative The Nuclear Threat Initiative (NTI) is a non-profit, non-partisan organization working to protect our lives, livelihoods, environment, and quality of life now and for future generations from the growing risk of catastrophic attacks from weapons of mass destruction and disruption (WMDD)—nuclear, biological, radiological, chemical, and cyber. Founded in 2001 by Sam Nunn and philanthropist Ted Turner, NTI is guided by a prestigious, international board of directors. Joan Rohlfing serves as president. About the James Martin Center for Nonproliferation Studies The James Martin Center for Nonproliferation Studies (CNS) strives to combat the spread of weapons of mass destruction (WMD) by training the next generation of non-proliferation specialists and disseminating timely information and analysis. CNS at the Middlebury Institute of International Studies at Monterey is the largest non-governmental organization in the United States devoted exclusively to research and training on non-proliferation issues. Copyright © 2016 by the Nuclear Threat Initiative 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 written permission of the copyright holder. For permissions, send an e-mail request to [email protected]. The views expressed in this publication do not reflect those of the NTI Board of Directors or institutions with which they are associated. Contents Executive Summary ........................................................................................1 U.S. Navy Assessments ................................................................................2 HEU vs. LEU in Other Countries .......................................................................3 Introduction ..............................................................................................6 The Risks of HEU ..........................................................................................7 HEU and the NPT .........................................................................................9 Safeguarding HEU ........................................................................................12 HEU Use in Non-Weapons Military and Non-Military Applications .............................................13 Comparing Research Reactors, Power Reactors, and Naval Reactors .............................................16 The History of HEU in Submarines and Surface Warships ......................................................19 The United States ....................................................................................20 The Soviet Union/Russian Federation ...................................................................25 The United Kingdom .................................................................................29 France ..............................................................................................29 China ..............................................................................................32 India ...............................................................................................33 Argentina and Brazil .................................................................................35 Other States’ Naval Nuclear Propulsion Programs ........................................................36 Current Status of LEU Use in Naval Reactors .................................................................38 Nuclear Options for Future Naval Vessels ....................................................................39 The U.S. Navy’s Position on LEU Use in Naval Reactors ........................................................41 Analysis of the Navy’s Arguments on LEU Use ................................................................46 Technical Considerations .............................................................................46 Environmental Considerations .........................................................................49 Economic Considerations .............................................................................51 Proliferation Considerations ...........................................................................52 Arguments the U.S. Navy Could Stress .......................................................................55 Remaining Issues That Affect Naval HEU Use .................................................................56 Conclusions and Recommendations .........................................................................58 Appendix A: Naval Propulsion Reactors of the Various Nations .................................................61 Appendix B: Submarine Power Requirements .................................................................69 NTI Paper i www.nti.org Replacing Highly Enriched Uranium in Naval Reactors Executive Summary Minimization or elimination of globally held stockpiles of highly enriched uranium (HEU)1 has been a long-standing U.S. policy goal since the Carter administration in the late 1970s. Most states recognize that elimination or minimization of HEU would have significant benefits for global nonproliferation and counterterrorism efforts. These concerns have driven several efforts to eliminate or minimize HEU use in several applications. Significant progress has been made in reducing the use of HEU in civilian research reactors, in the preparation of isotopes used for medical purposes, and even in the elimination of weapons stockpile HEU by programs involving blending down the weapons grade HEU to low enriched uranium (LEU) fuel for civilian power reactors. The largest remaining non- weapons use of HEU is as fuel for naval propulsion reactors. In contrast to the attention given to other HEU minimization efforts, there has been relatively little international effort to eliminate or minimize the naval propulsion use. The topic has been addressed in some studies, particularly in the period shortly after the 9/11 attacks, and there has been some focus on the issue in the international arena, such as discussions at the two International Symposia on HEU Minimization.2 One of the major reasons for lack of progress in reducing HEU use in naval propulsion is that these are—except for the Russian ice breaker program—military programs, and the use of HEU, particularly for submarines, has historically been perceived to have a number of significant advantages. In addition, the non-weapons uses of HEU, such as for submarine propulsion, present a unique set of problems for the nonproliferation regime because, as is discussed in the body of this paper, there is a “loophole” in the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). The Russian Federation and the United States are the world’s largest holders of HEU, each of which has well over 500 metric tons (MT) of HEU.3,4 By comparison the next largest stock of HEU is the approximately 18 MT held by China. The sum total of HEU in all other states is on the order of 70 MT, a small fraction of the U.S./Russian total. The United States holds the largest declared reserve of HEU designated for naval reactors, approximately 140 MT. In addition, the U.S. Navy and United Kingdom’s Royal Navy almost exclusively use an HEU enrichment that is as high as or higher than that used in nuclear weapons. Other navies, such as the Russian Federation and the Indian Navy, typically use HEU that is enriched in the 40 percent to 50 percent range, approximately one half that of the typical enrichment for nuclear weapons.5 Finally, the remaining navies (France and China) that have nuclear-powered vessels use LEU fuel, most of which is enriched to a level of less than 10 percent. Currently, all marine propulsion reactors are military with the exception of the Soviet/Russian fleet of icebreakers/Arctic supply ships. Although the Soviet Union built its first icebreaker initially using an LEU core, it later retrofitted that vessel with HEU as well as all icebreakers that followed. These vessels are still operated by the Russian Federation. Except for the Soviet Union, early attempts at nuclear-powered commercial vessels elsewhere proved to be uneconomical; Japan, Germany, and the United States at one time built nuclear-powered commercial vessels fueled by LEU. These vessels are no longer in service. 1 HEU is by definition