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former Administrator of the National Nuclear Security Administration
March 7, 2018
Letter to the Editor: Detecting Clandestine Enrichment

James Acton

Trevor Findlay (“Looking back: The Additional Protocol,” Nov. 2007)  focused on the difficulties of verifying large bulk-handling facilities in his survey of future challenges. In reality, however, it is still the detection of clandestine nuclear activities that is the toughest challenge facing the International Atomic Energy Agency (IAEA)—exactly the problem that prompted a reworking of the safeguards regime in the 1990s. While the main product of that rethink, the 1997 Model Additional Protocol, has considerably enhanced the IAEA’s ability to detect certain clandestine activities, it has done much less to increase the IAEA’s prospects for detecting small gas centrifuge enrichment plants (GCEPs). Indeed, although David Albright and Jacqueline Shire (“A Witches’ Brew? Evaluating Iran’s Uranium-Enrichment Progress,” Nov. 2007) are absolutely right to highlight the importance of Iran restoring implementation of its version of the additional protocol, it is also surely true that this step alone would be insufficient to rebuild international confidence that Iran is not  carrying out undeclared centrifuge activity.

Given the putative nuclear renaissance and the economic attractiveness of the gas centrifuge as an enrichment technology, there is a danger that clandestine GCEPs could become de rigeur for proliferation. The most effective way to reduce this threat is to prevent the spread of gas centrifuge technology (and hence the knowledge of how to build and operate clandestine plants). Indeed, proposals that offer a guaranteed supply of nuclear fuel to states that voluntarily agree not to exercise their right to enrich could help accomplish this. Whether such fuel guarantees will be widely adopted, however, remains unclear.

In parallel, efforts also need to be made to enhance the IAEA’s ability to detect clandestine GCEPs. This is an extremely tough problem since environmental emissions from centrifuge plants are very small and hence wide area environmental monitoring (as envisaged by the additional protocol and discussed by Findlay) is not an realistic option for detecting them.

One approach to detecting clandestine GCEPs is to pay greater attention to the production of centrifuges and their components. As Albright and Shire point out, the manufacture of centrifuges is a complicated, demanding and expensive process; there are likely to be interconnections between a declared centrifuge manufacturing program and a clandestine one. Giving the IAEA greater legal rights to inspect facilities and talk to personnel involved in the manufacture of centrifuges may help it uncover such links. At the very least, permitting the IAEA to tag key centrifuge components would prevent a state from using a declared facility for the production of centrifuges for an undeclared programme.

The IAEA could also be given greater powers to monitor non-nuclear materials that are relevant to enrichment—such as fluorine gas. It would, of course, be utterly impractical to attempt any kind of materials accountancy on fluorine, but given that 70—80% of fluorine is used in the synthesis of uranium hexafluoride for enrichment,[1] declarations by member states on its production and use could potentially be useful for safeguards purposes. For instance, the discovery of undeclared fluorine manufacture (by open source analysis or even, conceivably, environmental monitoring) would be an indicator of clandestine nuclear activity. Fluorine is not the only non-nuclear material relevant to enrichment (maraging steel is another). Monitoring a few key non-nuclear materials could make a useful contribution to the safeguards system.

Finally, there is a need for national intelligence services to be more willing to share information with the IAEA (under article VIII.A of its statute the IAEA is entitled to receive and utilise such information). Indeed, the IAEA is in a unique position to compare intelligence data (ideally from a range of sources) with state declarations and information from its own inspectors. The results from such an analysis can be very useful in helping to guide a search for clandestine nuclear activities. National intelligence data is already used in this way to some extent, but by being more willing to share it, national governments could significantly enhance the IAEA’s ability to detect clandestine nuclear activity.

Unfortunately, the prospects for any improvements in the safeguards regime are bleak right now. As demonstrated by the debacle of “Committee 25” (which was tasked with finding ways of strengthening the safeguards system that would not require any new legal authority for the IAEA), few states have any appetite for more intrusive or effective verification. Ultimately, Findlay may well be right: a “punctuation”—quite possibly a proliferation shock—may be required to generate the international consensus required for reform. It would, however, clearly be desirable if the nonproliferation regime could be strengthened before further proliferation occurs.

The 2010 nuclear Nonproliferation Treaty Review Conference provides an opportunity to re-evaluate the regime. Success in strengthening the non-proliferation component of the regime (both in 2010 and beyond) will depend upon the burden of increased verification being sweetened by parallel concessions elsewhere. All states need to consider what form such concessions should take—but a particular responsibility must lie with the nuclear-weapon states and their willingness to make greater steps toward disarmament.


James Acton is a lecturer at the Centre for Science and Security Studies’ Department of War Studies at King’s College London. His previous research projects have included an analysis of IAEA safegaurds in Iran and a study on the detection of clandestine weaponization activities.



1. N. N. Greenwood and A. Earnshaw, “Chemistry of the Elements”, second edition, (Amsterdam: Butterworth-Heinemann, 1997), p. 797.

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