Monitoring Nuclear Weapons and Nuclear-Explosive Materials An Assessment of Methods and Capabilities (2005) / Chapter Skim
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4 Clandestine Stocks and Production of Nuclear Weapons and Nuclear- Explosive Materials
4 Clandestine Stocks and Production of Nuclear Weapons and Nuclear- Explosive Materials
Pages 183-216
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From page 183... ...
But undeclared nuclear weapons and NEM could exist as a consequence of retention of undeclared existing nuclear weapons and NEM or could come into existence by the clandestine production of nuclear weapons from existing NEM. In addition, undeclared NEM for weapons might be produced clandestinely or diverted covertly from peaceful nuclear power programs.
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From page 184... ...
In both cases, we attempt to estimate very roughly the maximum size of an undeclared stockpile or production activity that might go undetected. TABLE 4-1 Routes to Undeclared Nuclear Weapons Route to undeclared nuclear weapons Source of NEM · Move existing weapons to a clan destine storage or deployment fa cility None Required · Transfer of weapons from another state · Existing, undeclared stocks at · Assemble new weapons at clan- clandestine storage facility destine facility · New, undeclared production at clandestine facility · Covert diversion from declared stocks or production facility · Transfer from another state These highlighted routes to undeclared weapons are the principal focus of this chapter.
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From page 185... ...
National Technical Means The main problem with discovering undeclared stocks is knowing where to look. Existing storage facilities for nuclear weapons and NEM, such as the bunkers shown in Figure 2-3, are distinctive and easily detected and identified using National Technical Means (NTM)
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From page 186... ...
Human Sources The surest way to locate a clandestine storage facility for undeclared nuclear weapons or NEM is through human intelligence-for example, the leak of information by someone who has knowledge of the hidden stocks. Governments have varied in their ability to maintain secrecy.
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From page 187... ...
One may be able to increase the probability that individuals would report activities that contravene international agreements to international authorities. If the individuals most likely to have knowledge of undeclared activities can be identified, inspectors can request confidential interviews with these people.
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From page 188... ...
Imagery taken by photoreconnaissance satellites might show activity at variance with the records -- for example, movements of large numbers of weapons out of or into the plant during periods when the operating records showed little or no activity. Operating records for NEM production facilities also could provide evidence about the existence of undeclared weapons, or undeclared stocks of NEM that could be used to assemble them.
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From page 189... ...
As with weapons, archived intelligence information might be checked for consistency with the records; for example, imagery of a plutonium production reactor or a gaseous diffusion enrichment plant could indicate whether the plant is operating and, at least roughly, the level of production. Production records for NEM could also be checked for consistency with records for weapon assembly.
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From page 190... ...
Physical Evidence A variety of methods exist for gathering physical evidence that could be used to confirm NEM production records and resolve uncertainties or apparent discrepancies in them. These methods are sometimes referred to as "nuclear archaeology." In the case of graphite-moderated plutonium production reactors, for example, isotope ratios of impurities in the graphite can provide an accurate estimate of the total integrated neutron flux that was available to produce plutonium during the life of a reactor.4 Isotopes of various common impurities capture neutrons and produce heavier isotopes of the same element.
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From page 191... ...
This depleted uranium resulted from the production of HEU at various enrichment levels for nuclear weapons and fuel for naval, research, and test reactors, as well as LEU at various enrichment levels for civilian reactor fuel. Moreover, the isotopic composition of the feed varied significantly, including partially depleted and slightly enriched uranium recovered from irradiated reactor fuels in addition to natural uranium.
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From page 192... ...
In March 1993 President de Klerk announced that South Africa had built and dismantled six nuclear weapons. The IAEA was given a full history of the nuclear weapon program, along with a list of the people involved in it.
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From page 193... ...
Verifying South Africa's HEU declaration was complicated by the fact that uranium had also been enriched for nonweapons purposes, and poor records were kept of wastes and materials not valuable for the weapons program. According to then-Director General Hans Blix, "There is inherent difficulty in verifying the completeness of an original inventory in a country in which a substantial nuclear program has been going on for a long time."8 The irony is that South Africa's nuclear program, which produced a total of six weapons, may prove to be the smallest and shortest lived of all programs that produced a nuclear weapon.
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From page 194... ...
All things considered, the accounting uncertainties in plutonium and HEU stocks are likely to be no smaller than 2 and 4 percent, respectively.9 To put this in perspective, Table 4-2 expresses the estimated uncertainties in total plutonium and HEU inventories of the de jure and de facto nuclear weapon states in terms of an approximate number of "Significant Quantities" as defined by the 9In this discussion the "accounting uncertainty" is defined as two standard errors, in which case there is a 5 percent chance that the difference between the actual stock and the estimated stock is greater than the accounting uncertainty. The estimated stock plus or minus the accounting uncertainty is the 95 percent confidence interval for the actual stock, meaning that there is a 95 percent chance that the actual stock is within this range.
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From page 195... ...
, we judge that Russia and the United States probably could confidently conceal from statistical detection undeclared NEM stocks equivalent to several hundred nuclear weapons; the United Kingdom, France, and China could conceal undeclared stockpiles equivalent to one or two dozen weapons; and Pakistan, Israel, and India may be able to conceal enough NEM for at most one or two weapons. TABLE 4-2 Uncertainties in Plutonium and HEU Inventories (Number of Significant Quantities)
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From page 196... ...
Thus, the inspected party could not be highly confident that undeclared stocks much larger than one-fifth of the accounting uncertainty would escape statistical detection by the inspecting party. 1.0 0.8 Stock Detection 0.6 Undeclared of Statistical 0.4 Probability Escaping 0.2 0.0 0 1 2 3 4 Undeclared Stock (tons)
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From page 197... ...
This was the only major uncertainty in South Africa's declaration, because in this case the entire declared stock of HEU was available for inspection. But if a state also maintains substantial declared stocks of nuclear weapons or weapon components, the inspecting party would also have to consider uncertainties in its knowledge about the amount of NEM in these weapons and components.
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From page 198... ...
DETECTING UNDECLARED PRODUCTION OF WEAPONS AND NEM The other main route to the acquisition of undeclared nuclear weapons is to produce new weapons in undeclared production and assembly facilities. The key elements of such a program are shown in Figure 4-1.
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From page 199... ...
FIGURE 4-1 Key elements of a program to produce nuclear weapons.
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From page 200... ...
National Technical Means The principal means of uncovering evidence of clandestine production of NEM or nuclear weapons would be provided by NTM; for example, mining and milling operations can easily be identified using photoreconnaissance satellites. A clandestine program to produce 10 Significant Quantities of HEU or plutonium per year would require 40 to 80 tons of natural uranium per year,12 as well as chemical facilities to convert it into forms appropriate for enrichment or fuel fabrication.
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From page 201... ...
The gaseous diffusion enrichment plants built by several of the nuclear weapon states are easy to detect by virtue of their enormous size, electrical power requirements, and heat output. A small gas centrifuge enrichment plant, on the other hand, would be much easier to conceal or disguise.
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From page 202... ...
Human sources are likely to be much more valuable in detecting the undeclared production of nuclear weapons or NEM, compared with the detection of undeclared stocks, simply because of the far greater number of individuals that would be involved in building and operating production facilities. The secret South African weapons program, for example, which produced six nuclear bombs, reportedly employed a total of 1,000 people (but no more than 300 at any one time)
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From page 203... ...
provides for a network of 80 air-sampling stations to detect radioisotopes released from clandestine nuclear tests. Similar "wide-area" environmental sampling networks have sometimes been proposed to detect clandestine production of NEM.
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From page 204... ...
Centrifuge enrichment facilities can have extremely low routine release rates, although a large pipe break or the failure of a number of centrifuges might release significant amounts of enriched uranium into the environment. Gaseous diffusion and electromagnetic separation facilities have much larger routine release rates, but it is highly unlikely that a state wishing to clandestinely produce HEU would use these older, much less efficient, and far more detectable technologies, unless they were unable to develop or otherwise acquire centrifuge technology.
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From page 205... ...
The IAEA study estimated that the krypton-85 released from a small reprocessing facility could be detected by a continuous gas sampler at distances of over 100 kilometers downwind under stable atmospheric conditions, with high detection probability and low false alarm rate. The study concluded that a network of 26 sampling stations would have a high probability of detecting the operation of a clandestine reprocessing facility within the portion of a million square kilometer area of the Middle East most capable of supporting a clandestine facility.17 In addition, particulate sampling may be useful for detecting accidents at reprocessing plants.
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From page 206... ...
.18 Releases from gaseous diffusion and electromagnetic isotope enrichment plants would be much larger and more detectable. Unless substantial progress is made in reducing the cost or increasing the sensitivity of analyzing uranium particulate samples, wide-area environmental sampling would be a practical method of detecting undeclared uranium enrichment activities only over small areas, such as the Korean peninsula.
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From page 207... ...
The right to conduct on-site inspections of suspect sites is provided for in the Additional Protocol to the IAEA safeguards agreements, as well as various other multilateral and bilateral arms control treaties. The modalities of how a challenge inspection would be initiated and conducted would depend on whether an agreement was bilateral or multilateral.
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From page 208... ...
intelligence in identifying foreign nuclear weapon programs is a valuable reference point for evaluating the likelihood that clandestine weapons programs would be detected in the future. At present the record and even some underlying capabilities of U.S.
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From page 209... ...
13-2-60, "The Chinese Communist Atomic Energy Program," December 13, 1960; National Intelligence Estimate [NIE] 13-2-62, "Chinese Communist Advanced Weapons Capabilities," April 25, 1962; Special National Intelligence Estimate [SNIE]
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From page 210... ...
India's nuclear test in 1974 came as a surprise,27 but the suspicious nature of the secretive Indian nuclear program was recognized a number of years earlier and the facilities supporting the development of the device had been identified.28 diffusion plant has not been completed. If this plant is in fact intended to be a gaseous diffusion facility, it probably could not produce weapon grade U-235 before 1965.
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From page 211... ...
In response to Pakistan's covert theft of Urenco centrifuge enrichment technology,30 the United States terminated economic and military aid to Pakistan in 1977 and again in 1979, many years before Pakistan was able to produce significant amounts of HEU and assemble its first weapon.31 · South Africa. The goals of the South African nuclear program were long suspect, particularly when in the 1970s South Africa developed the Helikon enrichment process capable of producing HEU.32 The United States cut off nuclear cooperation in 1976 due to South Af rica's refusal to sign the NPT.
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From page 212... ...
35 Gary Samore, ed. North Korea's Weapons Programmes: A Net Assessment, An IISS Strategic Dossier (Basingstoke, UK and New York, NY: International Institute for Strategic Studies and Palgrave Macmillan, 2004)
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From page 213... ...
The United States pressed China and Russia throughout the 1990s to curtail their nuclear cooperation with Iran, citing intelligence infor mation indicating that Iran intended to develop nuclear weapons. Evidence of a secret centrifuge enrichment program began to emerge publicly as early as 1995, and in August 2002 the existence of a secret nuclear facility at Natanz was revealed by an Iranian opposition group.38 Perhaps in response to these leaks, in 2003 Iran opened what it claimed to be all of its facilities to IAEA inspection, including a pilot centrifuge enrichment plant under construction near Natanz.39 The controversy over Iran's nuclear program continues, but the relevant point here is that the existence of the NEM production pro gram was discovered well before weapons or signifi cant amounts of HEU were produced.
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From page 214... ...
As noted in the previous section on environmental monitoring, an on-site inspection would be highly likely to detect any significant undeclared activities, such as the enrichment of uranium or the separation of plutonium. Based on the historical evidence, and with these additional capabilities, we judge that a clandestine nuclear weapons program very likely would not escape early detection.
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From page 215... ...
Given the extensive knowledge of existing nuclear programs, the massive amounts of additional information that would result from the process of verifying declarations, the new inspection capabilities provided by the IAEA Additional Protocol, and the demonstrated capabilities of NTM, it is very unlikely that any state, including Russia, participating in a cooperative fashion involving detailed declarations could develop a complete, stand-alone covert nuclear weapon production program that would not be discovered over time. If, however, undeclared stocks of NEM exist or can be diverted without detection from civilian stocks or production facilities, it is much more likely that the assembly of new weapons could escape detection.
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From page 216... ...
216 MONITORING NUCLEAR WEAPONS AND NUCLEAR-EXPLOSIVE MATERIALS lute uncertainties would be much less, leading to the possibility that these countries could conceal undeclared stocks equivalent to one or two dozen weapons in the case of China, and at most one or two weapons in the case Israel, India, and Pakistan. Confidence that declarations were accurate and complete, and that covert stockpiles or production facilities did not exist, would be increased by the successful operation of a monitoring program over a period of years in an environment of increased transparency and cooperation.
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