The most widely accepted estimates of India's plutonium production have been made by David Albright (
[Albright et al 1997],
[Albright 2000]). His most recent estimate (October 2000) was that by the end of 1999 India had available between 240 and 395 kg of weapon grade plutonium for weapons production, with a median value of 310 kg. He suggests that this is sufficient for 45 - 95 weapons (median estimate 65). The production of weapon grade plutonium has actually been greater, but about 130 kg of plutonium has been consumed - principally in fueling two plutonium reactors, but also in weapons tests. His estimate for India's holdings of less-than-weapons-grade plutonium (reactor or fuel grade plutonium) are 4200 kg of unsafe guarded plutonium (800 kg of this already separated) and 4100 kg of IAEA safeguarded plutonium (25 kg of this separated). This unsafeguarded quantity could be used to manufacture roughly 1000 nuclear weapons, if India so chose (which would give it the third largest arsenal in the world, behind only the U.S. and Russia).
| Research Reactors at Trombay |
|---|
| Name | Year | Type |
| Apsara | August 1956 | Swimming pool type |
| CIRUS | July 1960 | Canadian reactor |
| Dhruva | August 1985 | Heavy water cooled & Moderated |
There has been conflicting statements regarding the lifetime capacity factors of the Dhruva and CIRUS reactors. U.S. officials, for example strongly feel that India's Cirus and Dhruva plutonium production reactors have a lifetime capacity factor of about 40 percent whereas. Indian officials have stated that the avera
ge capacity factor is significantly greater, as large as 60 percent. Thus for the estimate, the most likely choice was selected as 40 percent with values up to 60 percent having a diminished probability of occurring. On the other end, a lifetime capacity factor less than 30 percent was viewed as highly unlikely.
India's inventory was estimated by arriving at the total production of weapon-grade plutonium in the Cirus, Dhruva, and power reactors and thereafter subtracting the amounts used in nuclear testing, processing losses and civil uses of the plutonium in the power reactors. The median value, which is the value midway between the smallest and largest value, is about 310 kilograms of weapon-grade plutonium at the end of 1999. The estimated values range between 180 kilograms and 480 kilograms. But the values in the most probable 90% an 10% percentile range are 250 kilograms and 375 kilograms.
Latest update from Albright 2004 document...........
While making the latest estimates the lifetime capacity factor the Cirus reactor, covering the period from start up in 1960 until shutdown in 1997, is estimated as a triangular distribution in the Crystal Ball® calculations, with the most likely value as 50 percent and the minimum and maximum values as 30 and 70 percent have been used.
The capacity factor for the Dhruva reactor is estimated for two different periods. The first period stretches from 1985 through 1998, and the second period is from 1998 through 2004.
The capacity factor for the first period is represented as a triangular distribution with the most likely value as 40 percent and the minimum and maximum values as 30 and 60 percent, respectively.
For the second period, the multi-year capacity factor is represented as a uniform distribution with a minimum of 55 percent and a maximum of 75 percent.
The calculation for total plutonium production for the military program through 2004 gives a median value of about 575 kilograms of weapon-grade plutonium. The range is defined as all values between the 5th and 95th percentiles, which are 495 and 665 kilograms, respectively. One way to interpret the results is that there is a 90 percent certainty that the true value lies between 360 and 530 kilograms of weapon-grade plutonium, where the median value is about 450 kilograms.
The largest overall users of plutonium from these reactors have been civil reactors utilizing plutonium fuels, including the Fast Breeder Test reactor (FBTR), the Purnima reactor, the Zerlina reactor, and power reactors. Nuclear testing in 1974 and 1998 also used a portion of this plutonium.
As above, many of these draw downs had to be estimated and are represented by ranges in the calculation. The calculation for the total amount of draw downs has a median of about 130 kilograms and 5th and 95th percentiles of 110 and 150 kilograms, respectively.
At the end of 2004, the median value of the estimate of this inventory is 445 kilograms of plutonium, and the 5th and 95th percentiles are 360 and 530 kilograms, respectively.
