Chapter seven Assessing the proliferation risks of civilian nuclear programmes Nuclear power plants alone are not a prolifera- ence of small clandestine gas-centrifuge enrichment tion risk. Without enrichment or reprocessing plants is the greatest challenge. Unlike reactors or capabilities, power-reactor fuel, whether fresh or reprocessing plants, such facilities produce very spent, cannot be used for the production of nuclear few environmental emissions or other transmis- weapons. There are various ways, however, in sible signatures, and so can be extremely difficult which reactor projects and related nuclear fuel-cycle to detect. Enrichment plants can also be housed in facilities could be used to further a nuclear-weapons small and nondescript facilities, or buried under- development programme. This chapter describes ground, and thus can be hard to discern from these various possible proliferation pathways. overhead imagery. A state that complements a It should be stressed that no successful nuclear- nuclear-reactor programme with such sensitive weapons programme has ever relied on commercial fuel-cycle technologies (which could be replicated reactors. Most of the states that have pursued in secret) thus presents a possible proliferation weapons programmes went on to construct nuclear concern. power plants, but only after their dedicated mili- In the event that a violation is detected, any tary programmes were successful, nearing success enforcement actions are at the discretion of the IAEA or had been abandoned. The scenarios for prolif- board of governors and the United Nations Security eration activities related to nuclear power plants Council. The efficacy of the system for ensuring described here are, therefore, only hypothetical, but compliance with safeguards agreements is therefore they cannot be ruled out, especially in light of the dependent on the effectiveness of IAEA safeguards, increasing availability of nuclear-weapons-related the mechanisms for agreeing on enforcement actions technologies spread by black-market networks.1 and the enforcement actions themselves. As outlined in the introduction to this dossier, IAEA standard safeguards are designed to detect Sources of plutonium in a timely manner the diversion of nuclear mate- In all nuclear reactors, the irradiation of uranium rial from declared nuclear facilities. Diverting fuel produces plutonium, among other products. material from declared and safeguarded fuel-cycle In military-dedicated reactors (including research facilities is difficult; it is likely that a would-be reactors that are actually operated for weapons nuclear-weapons state would construct clandestine purposes), plutonium production is the intent. In facilities as part of a parallel secret programme. The civilian power reactors, plutonium is a by-product effectiveness of IAEA safeguards, even with the of electricity generation. For plutonium to be used strengthening provisions of the Additional Protocol, in a nuclear weapon, it has to be separated out from varies according to the type of facility in question. the other materials and fission products that make Nuclear power plants themselves are relatively up most of the spent fuel. The spent fuel contains straightforward to safeguard. Detecting diversion highly radioactive fission products. Separating at facilities which handle large quantities of liquids, plutonium from spent fuel without posing a severe gases or powders (known as bulk-handling facili- hazard to workers requires a heavily shielded dedi- ties), such as full-scale enrichment or reprocessing cated facility and a series of remotely operated plants, is more of a challenge. Detecting the exist- chemical separation steps. Nuclear Programmes in the Middle East: In the shadow of Iran 141 Chapter seven Power reactors IAEA inspections The plutonium produced as a by-product of nuclear- power generation can be used to make a nuclear The activities that IAEA inspectors perform during 2 device, though it is not optimal. The problems inspections include: associated with the use of power-reactor fuel come examining facility records and comparing them about as a result of the length of time for which fuel with reports submitted by the state; is irradiated in this type of reactor. If reactor opera- verifying declared inventories and flows of tors remove the spent fuel after a low ‘burn-up’ (a nuclear material (e.g., through item counting, few weeks of irradiation), the plutonium will have a non-destructive assay measurements, material high concentration of Pu-239, the plutonium isotope sampling for destructive analysis); best suited for use in a nuclear weapon. In practice, verifying, under item-specific agreements, however, reactor operators normally irradiate fuel certain non-nuclear material and equipment; for two to six years, which results in ’reactor-grade applying containment and surveillance plutonium‘ that has a larger quantity of other, less measures; desirable, plutonium isotopes. The isotopes Pu-238 confirming the absence of undeclared activities and Pu-240 are particularly problematic because (e.g. unreported nuclear production at reactors, they have a high spontaneous fission rate that could or the undeclared use of reprocessing and enrichment plants or hot cells), such as through cause premature initiation of the chain reaction taking environmental samples; and resulting in a dramatically reduced explosive yield. confirming the absence of borrowed nuclear The heat emitted by the alpha decay of the Pu-238 material from another facility in the state that isotope and the intense gamma radiation emitted by could be used to conceal diversion. Pu-241 and its decay products also complicate the Source: The Safeguards System of the International Atomic use of reactor-grade plutonium in a nuclear weapon. Energy Agency, http://www.iaea.org/OurWork/SV/Safeguards/ safeg_system.pdf, p. 12. But although a weapon using reactor-grade fissile material would tend to have an unreliable yield, even a ‘fizzle’ (a partial explosion) would still create a very large blast. North Korea’s 9 October 2006 test as research reactors; examples are the facility Iran is often described as a fizzle (though the cause of is building at Arak and the Es Salam reactor in failure remains a matter for speculation), as it had a Algeria. yield of less than 1 kilotonne of TNT. LWRs have an additional proliferation-resistant Whether or not a would-be nuclear power could feature in that their fuel cannot be loaded or removed build a successful nuclear weapon using reactor- without the entire power plant shutting down, which grade plutonium is a difficult judgment to make in principle should be readily observable by interna- without access to classified information.3 The use of tional inspectors or remote monitoring equipment. reactor-grade plutonium would be likely to reduce By contrast, reactors moderated by graphite or the predictability of the weapons’ yield, as new heavy water continue to operate during refuelling, proliferators are unlikely to have access to advanced thereby complicating safeguards against diversion. weapons designs that could overcome the pre- Because of the way in which nuclear reactors are ignition problem.4 But whether this would deter a refuelled, fuel assemblies discharged from a reac- proliferator from trying – given that a fizzle might tor’s core during the first refuelling are irradiated well be as powerful as a thousand large Second for a considerably shorter period of time than those World War bombs – is unclear. normally discharged in subsequent refuellings. They Power reactors fuelled with natural (or slightly therefore contain a higher proportion of Pu-239. In enriched) uranium and moderated by heavy water addition, fuel assemblies near the periphery of the or graphite produce spent fuel that is somewhat core are irradiated less than those near the centre. more suitable for nuclear weapons than is the spent Therefore, assemblies near the periphery of the core, fuel from light-water reactors (LWRs). Today, such particularly those of the first two discharges, are the reactors are rarely constructed for civilian power most desirable to divert. The fuel assembly of a large generation, though there is some interest in them power reactor can contain four to six kilogrammes 142 an IISS strategic dossier Assessing the proliferation risks of civilian nuclear programmes Areva Spent-fuel cooling pond of plutonium – approximately the amount of pluto- have several other features that make them poten- nium in a nuclear weapon. tially amenable to non-peaceful use. Indeed, If the location within a reactor’s spent-fuel pond ‘research reactor’ is a misnomer for the plants of of those assemblies with high-grade plutonium this type that have been used for dedicated nuclear- content was clearly marked, it might be possible for weapons purposes in several countries. Research preparations to be made for their clandestine removal reactors are relatively affordable, and require no and reprocessing. The diversion of assemblies from a more than a few dozen staff in total to operate nuclear power plant’s spent-fuel pool has never been them. Because their fuel burn-up is usually low, accomplished, so far as is known, and would be very research reactors often produce weapons-grade or difficult, if not impossible, to achieve, given thatIAEA near-weapons-grade plutonium. The quantity of safeguards cameras permanently survey spent-fuel plutonium produced annually in a research reactor ponds and transmit the