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Disarmament Diplomacy

Issue No. 49, August 2000

Deep Seas and Deep-Seated Secrets: Naval Nuclear Fuel Stockpiles and The Need for Transparency
By Morten Bremer Maerli


At first glance, naval nuclear fuel transparency and maintaining strong security on navy operations may seem at odds. Openness may introduce the risk of classified, sensitive or even proprietary information being compromised or released - conflicting with international obligations and with an adverse impact on national security.1 Transparency could increase vulnerability, as military defensive or offensive weaknesses may be disclosed. Moreover, widespread knowledge about the qualities and quantities of fissile materials, and possibly the systems of protection, could facilitate unlawful diversion.

So why then, should naval fuel stockpiles be subject to increased transparency? Confidence in non-diversion of the fissile materials to weapons-purposes is essential in this regard. Naval highly-enriched uranium (HEU) uses constitute a significant part of the total HEU-economy and the enrichment levels associated with naval fuel makes it potentially attractive for (crude) nuclear weapons. Existing and possibly future arms control agreements do not fully meet the proliferation challenges associated with the naval fuel cycles. The fuel cycles could thus constitute a backdoor to clandestine nuclear weapons-programs.

To limit the risk of diversion, the challenge will be to increase the transparency of naval fuel cycles, while protecting proliferation- and/or security-sensitive information. Taking this delicate balance into account, two possible approaches for naval transparency with different levels of intrusiveness are presented below. The prospects of such measures being implemented may be greater than anticipated, as political acceptance of the concept of transparency is emerging. This could, together with the new technical opportunities of high-quality and non-intrusive verification, create an important foundation for transparency initiatives on the highly sensitive naval fuel cycles.

The Need for Fissile Materials Stockpile Control

With the end of the Cold War, managing the vast quantities of nuclear weapons-usable materials have emerged as a one of the major challenges to international security. At the center of proliferation concerns is the direct use material that can be used for nuclear weapons without further enrichment or reprocessing, i.e. plutonium (Pu) and HEU.2 These materials are the key ingredients of nuclear weapons and their management and control is essential for reducing the potential for nuclear proliferation, nuclear war and nuclear terrorism. Unlike plutonium, most of the HEU is in military stocks.

More information is now available about the military nuclear programs than just a few years ago, but still, with some exceptions, no official figures of the military inventories of HEU (including naval stocks) in the nuclear-weapon states exist.3 The vast quantities of materials are managed with very little of the transparency that would be needed to build confidence that they are safe and secure or to provide the foundation for deep, transparent, and irreversible nuclear arms reductions.

Indeed, the stocks of fissile materials place a de facto upper limit on the number of warheads to be produced. Still, existing arms control agreements do not have any restrictions on the stockpiles of fissile materials. Large stockpiles of fissile materials could create a potential for "breakout" from treaty obligations. Moreover, uncertainties in fissile materials inventories could in fact prove to be the largest obstacle for verifying nuclear disarmament.4 Thus, making military nuclear arms reductions permanent will require that more information is made available about all military stocks of fissile material, including the naval stocks.

Naval Nuclear Propulsion

Naval HEU fuel is used for the propulsion of submarines and a limited number of surface vessels. The nuclear submarines offer unique projected and durable military capabilities, including launch platforms for nuclear missiles. Specific attributes make the naval fuel cycle potentially less proliferation resistant than other uranium fuel cycles. To achieve increased efficiency and higher energy output while maintaining the compactness of the naval cores, higher enrichment rates of HEU are used. The enrichment levels in US submarines exceed the levels in US nuclear weapons.

All the five declared nuclear-weapon states under the Non-Proliferation Treaty (NPT) possess nuclear propelled submarines.5 As nuclear-weapon states they are all exempted from international (IAEA) safeguards and verification and monitoring activities. Sensitivity concerns and the strategic importance of nuclear submarines cause the nuclear-weapon states to maintain a high degree of secrecy around its nuclear naval operations. Very little is officially known about submarine nuclear fuel designs, production technology, operational data and naval fuel stocks.

The United States and Russia have extensive nuclear propulsion programs, representing by far the largest fleets globally, using highly enriched uranium (HEU) in the reactor cores (see box). Their naval operations constitute a significant part of the total HEU-economy. An estimated total of 250-300 tons of HEU have been used in US and Russian naval programs since they were initiated, constituting some 10-15% of the countries' overall HEU production. As enrichment activities have now ceased in both Russia and the United States, the navies rely on weapon stocks of HEU for their naval propulsion program. This will, eventually, reduce the stocks of HEU, but will also limit the quantities of fissile materials declared excess to national military needs and put under international verification.6

Current and Future Naval Fuel Loopholes

The strategic importance of the nuclear powered submarines makes probable a sustained interest in naval propulsion, both from the two Cold War superpowers, other nuclear-weapon states and possibly new nuclear submarine wannabes - or even clandestine weapon producers.7 Institutional frameworks are in place to limit the potential diversion of the proliferation attractive naval material. However, both existing and possibly future treaties have limitations for securing non-diversion of naval fuel. The result could be new HEU-markets, in addition to the existing excessive military HEU-stockpiles, outside international control.

In 1988, India leased two nuclear submarines from Russia for three years. Pakistan subsequently discussed with China the possible acquisition of a nuclear submarine. The latter deal was never completed, but the willingness of the Chinese government to undertake such talks suggests that the two sides may well resume talks in the future.8 The Brazilian Navy has apparently again assigned priority to funds for a nuclear powered submarine. In July 2000, Brazil cancelled importation of their German-designed submarines. According to news reports, the vessels were unable to be equipped with the Brazilian nuclear propulsion systems under development.9

In addition, in view of the seeming success of the Russian naval nuclear propulsion program, the Russian Ministry of Atomic Energy (MINATOM) has proposed extending the uses of these reactors to provide electricity and heat to remote communities.10 The reactors will be placed on floating barges to be transported to costal areas or possibly underground, e.g. in mines, to make energy available locally. For the Russian government, they could offer a quick and effective solution to a vexing economic problem. For MINATOM in particular, the naval reactors could represent a new opportunity for Russian nuclear exports. Russian officials claim that the International Atomic Energy Agency (IAEA) has approved the initial designs for these reactors.11

IAEA Safeguards and Naval Fuel

Safeguards on all nuclear activities in non-nuclear-weapon states make diversion of weapons-usable materials less likely. However, naval fuel may be an exception to the rule. Paragraph 14 of the model full-scope agreement allows states to withdraw nuclear material for peaceful uses from safeguards if it is being used for a "non-proscribed military activity".12 North-Korea has taken this option and now has an IAEA safeguards agreement allowing the non-application of safeguards to nuclear materials to be used in non-peaceful activities.13 The safeguards do stipulate that during the period of non-application of safeguards, the nuclear materials must not be used for the production of nuclear weapons or other nuclear explosive devices. They do not, however, prohibit the non-explosive use of nuclear material, equipment or technology for a military purpose such as the propulsion of naval ship. In this way, a back door is potentially left ajar to nuclear weapons acquisition.

A non-nuclear-weapon state under the NPT wishing to acquire enriched uranium for submarine propulsion could either invoke the safeguard exemption or could avoid IAEA safeguards entirely by obtaining unsafeguarded materials from a nuclear-weapon state or a non-NPT state.14 More elaborate scenarios could include non-nuclear-weapon NPT states building uranium enrichment and fuel fabrication plants for the production of submarine fuel and then claiming that the materials are not subject to IAEA-safeguards since they are dedicated to non-proscribed military use. In either case, the result would be that some of the HEU in a non-nuclear-weapon state under the NPT would not be subject to IAEA safeguards. There would be limited means for verifying that the materials and facilities were not being misused to make nuclear weapons. Both new guidelines and a new regime have been proposed and advocated to limit the potential impact of the current HEU-loophole in the Non-Proliferation Treaty, so far without significant political support.15

A Fissile Material Cut-Off Treaty and Naval Fuel

The long-standing proposal for a Fissile Material Cut-Off Treaty (FMCT) may gain new momentum, following the call by the recent NPT Review Conference for the Conference on Disarmament (CD) to commence negotiations immediately, with a view to its conclusion within five years.16 Failure to do so would be likely to harm the nuclear non-proliferation regime in the long run. Under an FMCT, the five NPT nuclear-weapon states and states not party to the NPT would be prohibited from producing any HEU or Pu for nuclear explosives.

However, even if the consensus-benumbed CD does now manage to make progress with the FMCT-negotiations, materials for naval propulsion are likely not to be included. It is the firm expectation of the US, for example, that an FMCT would prohibit the production of HEU, plutonium, and uranium-233 for nuclear explosives, but not prevent the production of tritium or the use of HEU for non-explosive military uses such as naval reactors.17 Thus, in addition to the existing NPT loophole, another loophole may be created in a future FMCT.

Somewhat surprisingly, the existing IAEA full-scope safeguards model agreement has been suggested as a model for dealing with naval fuel under a FMCT.18 If this were so, one hole would then be "plugged" with another hole, causing potentially new leakages. To be efficient, such an approach will require prenotification of the IAEA by states intending to use fissile materials subject to the treaty for non-military applications. The IAEA then will have to carry out verification measures to see that those materials are not diverted from their declared use, if such notification is given by the "host" country. Moreover, to what extent nuclear-weapon states are willing to submit to FMCT-verification along traditional IAEA-safeguards activities remains an open question, as will surely be the case for states non-party to the NPT.19

By omitting the naval fuel cycle, the FMCT will be a non-comprehensive and thus inconclusive treaty, leaving room for diversion of HEU for clandestine nuclear weapons programs. The mere possibility of such programs could create a climate of distrust, as suspicions about such activities easily could arise. Confidence-building through transparency on stocks dedicated to naval propulsion could restore some of the trust.

Naval Fuel Transparency

The major incentive for promoting transparency and possibly international safeguards activities on existing stocks of fissile naval materials is not primarily to supply security to the safeguarded materials, but to provide international confidence with respect to non-diversion.20 Transparency may be defined as a "cooperative process that is based on thorough risk-benefit assessments and that (1) increases openness and builds confidence, (2) promotes mutual trust and working relationships among countries, national and international agencies, and the public, and (3) facilitates verification and monitoring measures by information exchanges."21

As this definition suggests, transparency is more than a description of a nuclear program or a specific site. Based on voluntary measures, it permits the accumulation of data, both directly and indirectly, over an extensive period of time to build confidence that the behavior of a country or a collection of countries is consistent with agreements and norms. Transparency has, descriptively enough, been referred to as "permitted knowledge". In fact, the voluntary release of information is the true measure of transparency, while taking extra steps of openness beyond expectations will promote higher levels of confidence. Progress in the number of states allowing transparency and eventual verification on their nuclear stockpile activities is likely to encourage other states to participate.

Naval Fuel Transparency Based on Declarations

Declarations are not normally verifiable and evasions could take place undetected. However, implemented in a proper manner, declarations can have an important confidence-building effect by making it less probable that diversion of fissile materials will occur. Such declarations could be part of bilateral agreements on data exchanges on the aggregate stockpiles of fissile materials, based on existing bilateral commitments of transparency, or take place under special naval information exchange agreements. As a minimum, a non-intrusive, voluntary naval transparency approach could include, on a regular basis, declarations of:

  • Quantities of HEU dedicated to naval propulsion
  • Quantities of spent naval fuel
  • Estimates of future HEU naval needs
  • Naval fuel, if any, declared excess and put under international verification
The approach proposed will allow for the provision of information on the total quantities of HEU dedicated to naval propulsion, while protecting any detailed and possibly sensitive information regarding the fuel and reactor operations. Due to the large uncertainties in the current quantities of stocks of fissile materials, comprehensive initial declarations are particularly important. Declarations of fresh and spent fuel can be compared to initial declarations. Moreover, the validity of the declarations can be tested by comparisons with estimated and calculated consumption levels.

If acceptable, confidence in the declarations given could be boosted through non-intrusive spot checks verifying the status of spent fuel. If the spent fuel is reprocessed, inspectors could check the declarations against weights and the assays of the recovered uranium and plutonium, including the quantities of uranium-236 in the residual uranium.22

Naval Fuel Transparency with Verification

While verification of the transparency measures is clearly desirable, such a regime will be more intrusive and thus also more challenging to implement. Effective verification would have to include inspections along the fuel cycle. Knowledge of the production history of the naval fuel-producing facilities militates against clandestine production and raises confidence that no such production is taking place. But while verification at the production facilities is preferable, this is unlikely to be accepted due to sensitivity problems.

Under the arrangement suggested here, all naval fuel leaving the production plants would be verified, and then reverified if put in intermediate storage before entering the naval reactors. Preferably, tags and seals would be introduced on the transportation containers, leaving the inspectors with an opportunity to trace and track specific batches of fuel. Once the fuel is introduced into the naval reactors, verification could provisionally end, as the radiation levels will make the fuel self-protective after the first chain-reactions have been initiated. After defueling, tags and seals could be reintroduced to the transportation and/or storage containers. Finally, the quantities of spent naval fuel would be monitored prior to any final disposition (for once-through cycles) or possible reprocessing and subsequent downblending.

This approach would give an opportunity to verify the operative status of each naval fuel batch (in storage, in transport or in reactor), and should thus give a high level of confidence in non-diversion of HEU. Protecting proliferation sensitive information in the presence of international inspectors would be challenging. This could, however, be managed with the introduction of proper working procedures for the inspectors and equipment with "information barriers".

Why This Could Work: Implementation of Naval Fuel Transparency

A combination of technical and political opportunities could make transparency on the naval fuel cycle more than a bookish exercise in nuclear arms control. Existing unilateral, bilateral and multilateral transparency commitments could support the suggested schemes for naval fuel cycle declarations. Verification, while protecting proliferation sensitive information, could be facilitated by emerging technologies and ongoing cooperative nuclear security efforts.

Unilateral and Bilateral Fissile Materials Transparency Commitments

Official data on the military plutonium and HEU stocks have generally not been available outside governments. In most countries possessing nuclear weapons or countries trying to acquire them, information about fissile weapons-usable materials stocks are still classified. However, during the latter part of the 1990s, a political shift has taken place and there is now widespread agreement that greater transparency is a desirable goal.23 The 2000 NPT Review Conference reaffirmed this shift and called for increased transparency by the nuclear weapon states with regard to the nuclear weapons capabilities and the implementation of agreements pursuant to Article VI and as a voluntary confidence-building measure to support further progress on nuclear disarmament.24

As part of its Openness Initiative, the US Department of Energy released a report on the United States plutonium production, acquisition, and utilization from 1944 through 1994.25 A similar report on the HEU stockpile and uses is expected in the near future.26 The intention behind the first plutonium report was to assist discussions of plutonium storage, safety and security with stakeholders as well as to encourage other nations to declassify and release similar data.27 Meanwhile, after reconsidering the levels of confidentiality about the stocks of fissile materials required for national security reasons, the British government concluded that there is no longer a need for complete confidentiality about these stocks. Their total stockpiles of plutonium and uranium held outside international safeguards was therefore declared in June 1998.28

Russia has not released any official information on its fissile materials stockpiles. Officials and laboratory experts have indicated that Russia does not currently have funds available to compile the information in a form comparable to that in which the United States released details of its plutonium stockpile.29 Since 1994, however, the US and Russia have tried to launch several bilateral nuclear warhead and materials transparency initiatives.30

Multilateral Fissile Materials Declarations

Established international mechanisms for declaration of fissile weapons-usable materials could also be a point of departure for naval fuel declarations. In 1998, the IAEA published Guidelines for the Management of Plutonium (INFCIR/549).31 These guidelines, agreed to by the five NPT nuclear-weapon states plus Belgium, Germany, Japan and Switzerland, increase transparency on the management and the holdings of civil plutonium. The guidelines also apply to plutonium declared excess to military nuclear programmes. Plutonium in spent fuel is not the focus of the guidelines, but each country has agreed to publish annual estimates of the amount of plutonium in its spent nuclear fuel.

As for the proposed schemes for naval stockpile transparency, the plutonium declarations will focus on aggregate quantities associated with the materials in question. States that have agreed to the plutonium guidelines should annually publish:

  • Occasional brief statements explaining their national strategy for nuclear power and spent fuel, and their general plans for managing national holdings of plutonium
  • An Annual Statement of their holdings of all plutonium subject to the guidelines
  • An Annual Statement of their estimate of the plutonium contained in its holdings of spent civil reactor fuel
Non-Intrusive Verification

Given the sensitivity of the naval fuel cycle, transparency measures involving verification are dependent upon non-intrusive techniques. Equipment with "information barriers" is designed to allow the inspectors to derive sufficient, credible information for the verification, while preventing access to classified information. This type of equipment is being developed both for the US-Russian HEU-deal, where 500 tons of Russian weapons HEU will be downblended and utilized in commercial US power reactors, and for the Trilateral US-Russian-IAEA initiative for verification of excess materials. Development of equivalent technical verification solutions for the HEU-fuel cycle could be feasible.

After a slow start and organizational difficulties, the implementation of the HEU-agreement is accelerating and new transparency measures have been put in place.32 The US Department of Energy needs to verify three things: that the HEU is extracted from nuclear weapons, that the same HEU is oxidized, and finally that the HEU is blended into low-enriched uranium (LEU).33 MINATOM must confirm that the resulting LEU has been fabricated into fuel for commercial nuclear power reactors. Portable instruments are used to confirm the presence of HEU in weapons component containers. The portable units determine the level of U-235 enrichment of metal chips that results from the machining of the HEU metal components from the weapons.34 Despite the fact that a system less intrusive and less likely to reveal sensitive information was chosen, in over two years of operation all its measurements have been consistent with the declared enrichment.35

Under the Trilateral initiative, the requirement is not to verify the weapons origin of HEU and plutonium but to promote international confidence that the material is not used in the production of new weapons. Thus, the aim is to provide transparency on the steps taken to reduce the stocks of fissile material potentially available for the use in nuclear weapons programs. Commitments to the initiative must be irrevocable and verification must follow from storage through the disposition activities, remaining in effect until the fissile material is rendered no longer usable in nuclear weapons.

To begin IAEA verification as early as possible, special technical provisions are being developed that will allow the two states to submit dismantled nuclear weapon components or other classified forms of fissile material, with the assurance that IAEA inspectors will not acquire information relating to the design or manufacture of such weapons.36 The US ensures that the materials (and facilities) which have been opened for international inspection will not provide IAEA-inspectors with proliferation sensitive information. This is accomplished by vulnerability assessments, and by limiting the information given to the international inspectors to that determined to be safeguard relevant and mission essential.37

Important progress has been made in developing and testing verification equipment. Specifically, a prototype verification system for plutonium was built and demonstrated (under conditions expected in the field) at the Los Alamos National Laboratory. After reviewing available technologies, the prototype combined standard non-destructive measurement techniques and a new technology known as "information barriers" designed to allow the inspectors to derive sufficient, credible information for the verification, while preventing access to classified information. The prototype provided a means to evaluate the previously identified concepts, and the tests showed that verification under the security constraints could meet the security exigencies of the States and the verification requirements of the IAEA.38

Success in Materials Protection, Control & Accounting

In addition to the important progress that has been made in developing and testing verification equipment for sensitive fuel cycles, the progress in US-Russian naval nuclear Materials Protection, Control and Accounting (MPC&A) creates an important foundation for future naval transparency. The naval fuel cycle is one of three support sectors for ongoing US-Russian efforts to improve MPC&A (the other two are civilian nuclear sites and the nuclear weapons complex). By comparing progress in each of the sectors, it becomes apparent that the naval MPC&A upgrades clearly have been the most successful. The Navy program has been better able to deal with the sensitivity issues hampering other parts of the arrangement. Security systems have been installed at half of the naval sites and work has started on an additional third of the sites. Only five navy sites (one sixth of the total) remain uncovered.39 The close relationships established between US representatives and officials of the Russian Navy, the resolution of security concerns and the accounting of naval fuel at centralized storages with upgraded physical protection, are unique in the current security-clogged working environment. This creates an opportunity for continued openness and transparency cooperation.


The high enrichment levels associated with naval fuel make it proliferation attractive. Neither direct diversion of the highly enriched material nor naval fuel cycle-cover operations for clandestine nuclear weapons production can be excluded. As the current nuclear submarine possessors are all nuclear-weapon states under the NPT, this potential proliferation risk may seem less pressing. However, new nuclear submarine wannabes and possible exports of Russian naval reactor technology for electricity production could soon become reality together with new HEU-markets outside international control.

As current safeguards on stocks outside nuclear-weapon states and possibly a future Fissile Materials Cut-Off Treaty do not meet the proliferation challenges associated with the naval fuel cycles, voluntary transparency of naval activities could be introduced as a confidence-building supplement to international control. Promoting a norm for transparency on naval nuclear fuel could limit the risk of evasions of naval materials and could create important confidence in non-diversion to nuclear weapons production.

Ideally, current nuclear submarine possessors could take the lead and initiate transparency measures on the naval fuel stocks, along the lines outlined in this paper. Constructive security dialogues could then supersede years of "instinctive" secrecy on naval fuel cycle activities. Indeed, the success of the US-Russian naval MPC&A program, political transparency commitments and equipment with "information barriers", allowing for high-quality verification with a low level of intrusiveness, represent a unique opportunity for implementing naval transparency measures in Russia. A prerequisite for this, however, is an equal level of candour on the US side.

Transparency norms in this field will support future efforts of non-proliferation and nuclear disarmament, as knowledge of all quantities of weapons-usable stocks could create an important foundation for irreversible and deeper reductions in nuclear arsenals and for finding sustainable non-proliferation solutions. Increased naval transparency could therefore not only be in the security interest of today's nuclear powers, but of all states.

Notes and References

1. In accordance with Article I of Treaty on the Non-Proliferation of Nuclear Weapons, nuclear weapons states shall not in any way assist, encourage, or induce any non-nuclear-weapon states to manufacture or otherwise acquire nuclear weapons or other nuclear explosive devices, or control over such weapons or explosive devices.

2. In accordance with internationally accepted standards regarding special fissionable and weapons-usable ("direct-use") materials, and as reflected in IAEA definitions and practices, the materials are plutonium 239, highly enriched uranium (that is, uranium containing more than 20 percent uranium 235), uranium 233, and material containing any of the foregoing.

3. The United Kingdom is a noteworthy exception, having declared the total size of stockpiles of uranium (and plutonium) held outside international safeguards.

4. Steve Fetter (1996) "Verifying Nuclear Disarmament", Occasional Paper No. 29. The Henry L. Stimson Center, p. 15. US estimates of the size of the Russian fissile materials stockpile is uncertain to more than a hundred tons

5. France and China use Low Enriched Uranium (LEU) in their submarines.

6. Now a large portion of the US military non-weapons-grade HEU is turned over to civil uses, partly under international verification. Nearly everything of the high-quality weapons-grade uranium, however, is kept for naval reactors. Current US Navy supplies are sufficient for many decades. Still, the US Navy maintains its right to withdraw any fissile weapons-usable material ever put under international safeguards. From Bunn, M. (2000) The Next Wave: Urgently Needed Steps to Control Warheads and Fissile Materials. Advance Copy. Carnegie Endowment for International Peace, p. 54 and Albright, D. Walker, W. and Berkhout, F. (1997) Plutonium and Highly Enriched Uranium 1996: World Inventories, Capabilities, and Policies. Oxford University Press. New York. p. 93.

7. The potential proliferation impact of nuclear submarines has been an issue of great concern for decades. See e.g. Miller, M. "Nuclear Submarines and their Implications for Weapons Proliferation". In Leventhal, P. and Tanzer. S. (eds.) Averting a Latin American Nuclear Arms Race (Nuclear Control Institute, Washington, DC and Macmillan Press, 1992), Sanders, B. and Simpson, J. "Nuclear Submarines & Non-Proliferation: Cause for Concern", Programme for Promoting Nuclear Non- Proliferation (1988), Desjardins, M. F. and Rauf, T. (1988) Opening Pandora's Box? Nuclear Powered Submarines and the Spread of Nuclear Weapons, Aurora Papers No. 8, and Moltz, J.C. "Closing the NPT Loophole on Exports of Naval Propulsion Reactors", The Nonproliferation Review, Fall 1998.

8. Moltz, J. C. (1998), p. 110.

9. "Brazilian Navy to Develop Nuclear Submarine With National Technology". Valor (in Portuguese), Sao Paulo, 5 July, 2000.

10. From the Database of the Center for Nonproliferation Studies (CNS), Monterey Institute for International Studies.

11. Jeff Thein (1997), quoted in the CNS database.

12. IAEA INFCIRC/153 Corrected. "The Structure and Content of Agreements between the Agency and States Required in Connection with the Treaty on the Non-Proliferation of Nuclear Weapons. The loophole was deliberately part of the treaty to accommodate states that were considering nuclear-propelled naval crafts, and wished to avoid international inspections.

13. IAEA INFCIRC/403. "Agreement of 30 January 1992 between the Government of the Democratic People's Republic of Korea and the International Atomic Energy Agency for the Application of Safeguards in Connection with the Treaty on the Non-Proliferation of Nuclear Weapons".

14. The NPT only requires safeguards on special fissionable material provided to a non-nuclear-weapon state for peaceful nuclear activities. Miller, M. (1992), p. 160.

15. Guidelines for supply of submarine reactors and submarine launched missiles have been suggested by Sanders, B and Simpson, J. (1988) and a "Nuclear Propulsion Reactor Control Regime" has been proposed by Moltz, J.C (1998).

16. 2000 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons. Final Document. NPT/CONF.2000/28 (Vol. I, Part I and II), paragraph 15.3 under article VI.

17. McGoldrick, F, US Department of State, (1995) "US fissile material initiatives: Implications for the IAEA". IAEA Bulletin, vol. 37, no. 1.

18. Bragin, V., Carlson, J. and Hill, J. (1998) "Verifying a Fissile Material Production Cut-Off Treaty", The Nonproliferation Review, Fall 1998, p. 99.

19. Under the NPT, non-nuclear-weapon states (NNWS) already accept full-scope safeguards on their fissile materials, but the five NWS and the four non-members of the NPT do not have comparable obligations. Any attempt to use the FMCT to bring any of these states under identical arrangements as the non-nuclear-weapon states would probably lead them to reject the treaty.

20. For useful policy recommendations for nuclear materials transparency, see e.g. Task Force VI panel of CSIS (Center for Strategic and International Studies) for "Managing the Global Nuclear Materials Threat", CSIS (2000), Bukharin, O. and Luongo, K. (1999) US-Russian Warhead Dismantlement Transparency: The Status, Problems, and Proposals. PU/CEES Report No. 314. Princeton University. National Academy of Sciences (1994) Management and Disposition of Excess Weapons Plutonium. Committee on International Security and Arms Control. National Academy Press., Washington, D.C., and Fetter, S. (1999) "A Comprehensive Transparency Regime For Warheads and Fissile Materials", Arms Control Today, January/February 1999.

21. CSIS (2000), p. 53.

22. When a uranium-235 atom absorbs a slow neutron in a reactor, the probability of fission resulting is somewhat less than 90%. Non-fission absorption results in the formation of uranium-236, which have a half-life of 24 million years. The percentage of uranium-236 in a sample therefore reflects the amounts of uranium-235 which have been fissioned. Due to neutron absorption and further decay, more exact estimates of the quantities of uranium-235 fissioned, would involve measurements of some other isotopes as well.

23. Albright, D., Walker, W., & Berkhout, F. (1997), pp. 6-7.

24. 2000 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons. Final document. NPT/CONF.2000/28 (Vol. I, Part I and II), paragraph 15.9 under article VI.

25. DOE (1996), Plutonium: The First 50 Years. United States plutonium production, acquisition, and utilization from 1944 to 1994. DOE/DP-0137.

26. Personal communication with personnel at the Office of Defense Nuclear Non-Proliferation, DOE, April 2000.

27. DOE (1996), p. 5.

28. IAEA INFCIRC/570 Attachment. "United Kingdom Fissile Material Transparency, Safeguards and Irreversibility initiatives". A significant portion (4.4 tons of plutonium and over 9.0 tons of enriched uranium) of the stock has been made available for IAEA/Euroatom safeguards.

29. A contract in which the United States should undertake to pay the cost of preparing an inventory of Russia's plutonium stockpile in return for receiving information at the same level of detail as the Unites States has already released, has been proposed. From Bukharin, O. and Luongo, K. (1999), p. 23.

30. For political and technical reasons, all of the initiatives remain to be implemented. For an overview of US-Russian bilateral transparency initiatives, see Bunn, M. (2000), p. 47.

31. Although the annual publications of the civil holdings have been successful overall in creating more transparency, the declarations of several countries are incomplete. Moreover, in accordance with the goal of universal membership and adherence, more countries possessing civilian plutonium need to be involved.

32. See DOE (undated), "Megatons to Megawatts: Implementing HEU Transparency Measures,


33. While it clearly is the goal to verify that the uranium shipped originates from Russian weapons, doubts have been raised whether the measurements really can determine if the HEU is of weapons origin.

34. Mastal, E.F., Benton, J., and Glaser, J.W. (1999) "Implementation of US transparency monitoring under the US/Russian HEU purchase agreement." INMM Annual Meeting. Phoenix, Arizona.

35. Decman, D.J, Glaser, J., Hernandez, J.M. and Luke, S.J. (1999) "Portable NDA Equipment for Enrichment Measurements for the HEU Transparency Program". INMM Annual Meeting. Phoenix, Arizona.

36. IAEA (1999) "IAEA Verification of Weapon-Origin Fissile Material in the Russian Federation and the United States," Press Release, September 27,


37. Personal communication with personnel at the Office of Defense Nuclear Non-Proliferation, DOE, April 2000.

38. IAEA (1999).

39. GAO (2000) Nuclear Nonproliferation. Limited Progress in Improving Nuclear Material Security in Russia and the Newly Independent States. United States General Accounting Office. Report to Congressional Requesters. GAO/RCED/NSIAD-00-82, p. 30.


US & Russian Naval Nuclear Operations

The US naval propulsion program has designed, built and operated more than 30 distinct types of reactors.1103 US navy reactors were operating as of October 1999.2 Based on estimates during the 1980s, Cochran et al. found that a US submarine reactor core contains, on an average, 200 kg of U-235 enriched to 97.3% (the rest of the core being U-238).3 Larger as well as smaller charges are possible, but such enrichment levels are supported by other open source information.4 US naval nuclear propulsion materials are directly useable in nuclear weapons, where the highly enriched uranium is enriched to 93.5%.5 In terms of the number of submarines and naval reactors produced, the Russian naval program outmatches the US program. Officially, the Russian Navy currently operates 26 strategic nuclear submarines and 50 nuclear general-purpose submarines.6 However, Russian submarines are now at an all-time low in terms of deployment and readiness. The vessels spend significant time in port due to the current economic hardship in the country. Most Russian submarines are equipped with two reactors, and the overall number of submarine reactors produced by the Soviet Union/Russia is 458. Additionally, the eight ships in the Russian icebreaker fleet are nuclear propelled, each with one or two reactors, and accompanied by two battle cruisers with twin reactors.7 The total number of Russian naval reactors produced is therefore 473. Of these, a total of 24 reactors are believed to have been designed to use uranium enriched to 90% U-235.8

1. Schwartz, S.I. et al. (1998), The Atomic Audit. The Costs and Consequences of US Nuclear Weapons since 1940. (Brookings Institution Press. Washington, D.C., p. 140.)

2. Based on Sharpe, R. (ed.) Jane's Fighting Ships 1999-2000. 102nd edition, (Jane's Information Group Limited. Surrey UK. (1999)), pp. 789-838, and personal communication with personnel at the Naval Nuclear Propulsion Program Directorate.

3. Cochran, T.B., Arkin, W.M., Norris, R.S. and Hoenig, M.M. (1987) Nuclear Weapons Data Book. Volume II. US Nuclear Warhead Production. Natural Resources Defense Council. Ballinger Publishing Company. Cambridge, Massachusetts, p. 71. In addition to the U-238 fraction, some U-234 remnants from the enrichment process is probable.

4. E.g. Miller, M. (1992) "Nuclear Submarines and their Implications for Weapons Proliferation". In Leventhal, P. and Tanzer. S. (eds.) Averting a Latin American Nuclear Arms Race. Nuclear Control Institute, Washington, D.C. and Macmillan Press, p. 157, and von Hippel, F. and Levi, B.C. (1986) "Controlling the Nuclear Weapons at the source: Verification of a Cutoff in the production of plutonium and highly enriched uranium for nuclear weapons". In Tsipis, K. et al. (eds.) Arms Control Verification. The Technologies that makes it possible. Pergamon-Brassey's International, p. 367.

5. Roser, (1983). Quoted in Chow, B.G. and Solomon, K.A. (1993) Limiting the Spread of Weapons-Usable Materials. The National Defense Research Institute. RAND, p. 5, footnote 5.

6. "32 nuclear subs to remain in service" The Bellona Foundation, 25 May 2000. http://www.bellona.no/imaker?id=16916&sub=1

7. See Sharpe, R. (1999), pp. 556-574. For a description of the Russian nuclear icebreaker fleet, see Maerli, M.B., Ek, P. and Volkov, V. "Physical Protection of Nuclear Materials in the Nuclear Powered Icebreaker Fleet in Murmansk". Proceedings from a conference on physical protection of nuclear materials: Experience in regulation, implementation and operations, 10-14 November 1997 (International Atomic Energy Agency, Vienna, (1998)), p. 262.

8. Bukharin, O., "Analysis of the Size and Qualities of Uranium Inventories in Russia". Science and Global Security, Vol. 6. (1996), p.63.

Morten Bremer Maerli is a Science Fellow at the Center for International Security and Cooperation (CISAC), Stanford University. Thanks to George Bunn and John Finn at CISAC for useful comments while preparing the paper. Any errors or inaccuracies are the sole responsibility of the author, as are the views expressed. This paper and research was made possible during a beneficial stay at CISAC during the 1999-2000 academic year, with funding provided by the Fulbright Foundation, the Scandinavian-American Association, CISAC, NATO and the Norwegian Ministry of Defense.

© 2000 The Acronym Institute.

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