Central Estimates for Current and Former De Facto Nuclear Weapon States' Inventories of Unirradiated Plutonium and Highly Enriched Uranium (HEU) Produced in Nuclear Weapons Programs, end of 2003a
| Country | Category | Plutonium (kg) | HEU (kg) | ||
| Median | 5th-95th Percentiles | Median | 5th-95th Percentiles | ||
| Israelb | De Facto | 580 | 510-650 | ? | -- |
| Indiac | De Facto | 380 | 300-470 | HEU Production Possibled | -- |
| Pakistanc | De Facto | 40 | 20-60 | 1,100 | 1,000-1,250 |
| DPRKe | Ambiguous | 15-40 | -- | ? | -- |
| South Africa | Dismantled | 0 | -- | 430-580f | -- |
(a) The medians and the 5th and 95 percentiles in the table are calculated using the forecasting software Crystal Ball®. This software allows a more systematic and defensible uncertainty analysis. For North Korea (DPRK) and South Africa, ranges are given with no central estimate.
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(b) Israel's plutonium and HEU stocks remain difficult to estimate. The plutonium estimate is based on the Dimona reactor having a power of about 40 megawatts-thermal initially that increased to about 70 megawatts-thermal in the mid-1970s. Although significantly higher reactor powers are discussed publicly, the underlying reactor-based rationale for the higher reactor powers has proven hard to confirm or recreate. For a more detailed discussion, see D. Albright, Frans Berkhout, and William Walker Plutonium and Highly Enriched Uranium 1996 (Oxford: SIPRI and Oxford University Press, 1997). If the reactor power remained about 40 megawatts-thermal, total plutonium production would have been about 400 kilograms through the end of 2003. Although the reactor is about 40 years old, it is expected to operate for many more years. Public information suggests that Israel has had a gas centrifuge enrichment program, but this information is too spotty to determine whether Israel has a stock of HEU or, if so, its magnitude.
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(c) The values for India and Pakistan are updates of the estimates in India's and Pakistan's Fissile Material and Nuclear Weapons Inventories, end of 1999, by David Albright, October 2000.
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(d) India has been working on building a gas centrifuge plant for many years. The status of the project is rarely discussed in public, although progress should have been made. There has not been any public indication that the project was cancelled. Not enough public information exists to determine whether a significant amount of HEU has been produced in the facility or, if so, to estimate the size of an HEU stock. Nonetheless, based on the age of the project, India may now be producing HEU in significant quantities, perhaps enough to make both fission and thermonuclear weapons.
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(e) Because of the difficulty of estimating North Korea's plutonium stock, only a range is provided. North Korea has separated plutonium during two periods. It may have separated up to about 10 kilograms of plutonium prior to 1993. North Korea has stated that during the first half of 2003 it separated all the plutonium in a stock of fuel irradiated prior to mid-1994. Most experts accept that North Korea has separated a significant amount of plutonium from this irradiated fuel, but questions remain about whether North Korea separated all or the bulk of the plutonium in this fuel. The amount separated from this spent fuel is therefore preliminarily estimated to be between 15 and 30 kilograms of plutonium. In total, North Korea has an estimated 15-40 kilograms of separated plutonium. North Korea may have used gas centrifuges to enrich uranium. Available information suggests that little, if any, HEU has been produced in this program, but a great deal of uncertainty surrounds this issue.
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(f) South Africa dismantled all its nuclear weapons and associated programs in the early 1990s. In 1991, after the bulk of the dismantling occurred, South Africa had over 800 kilograms of HEU (average roughly 70% uranium 235), the vast bulk of which was unirradiated. Of this amount, South Africa used or irradiated about 200 kilograms of HEU in the Safari reactor as fuel (90% and 45% enriched) and targets (45% enriched). South Africa may recover the HEU used in the targets, about one-quarter of the 200 kilograms of HEU used in the reactor. Since the early 1990s, it may have blended down up to 150 kilograms of HEU in this stock of 800 kilograms to low enriched uranium. Thus, the unirradiated HEU stock at the end of 2002 was about 450-600 kilograms. This stock is estimated to have decreased in 2003 by roughly 20 kilograms of HEU that was used in the Safari reactor. South Africa's total HEU stock was roughly 600-750 kilograms as of the end of 2003.
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