SCARY facts about Pakistan's nuclear stockpile

Pakistan has the world's fastest-growing nuclear stockpile and it could achieve 150-200 warheads in a decade despite the political instability in the country, two top American atomic experts have said.

Pakistan is in the process of building two new plutonium production reactors and a new reprocessing facility to fabricate more nuclear weapons fuel, wrote nuclear experts Hans M Kristensen and Robert S Norris in the latest issue of Bulletin of Atomic Scientists.

In their paper Pakistan's nuclear forces, 2011, the authors estimate that if Pakistan's expansion continues, its nuclear weapons stockpile could reach 150-200.

"Despite its political instability, Pakistan continues to steadily expand its nuclear capabilities and competencies; in fact, it has the world's fastest-growing nuclear stockpile," they wrote.

"We estimate that Pakistan has a nuclear weapons stockpile of 90-110 nuclear warheads, an increase from the estimated 70-90 warheads in 2009," the paper said.

"It is also developing new delivery systems. Enhancements to Pakistan's nuclear forces include a new nuclear capable medium-range ballistic missile, the development of two new nuclear-capable short-range ballistic missiles, and the development of two new nuclear-capable cruise missiles," they wrote.

"With four new delivery systems and two plutonium production reactors under development, however, the rate of Pakistan's stockpile growth may even increase over the next 10 years," they warned.

"The Pakistani government has not defined the number and type of nuclear weapons that its minimum deterrent requires. But Pakistan's pace of nuclear modernisation and its development of several short-range delivery systems indicates that its nuclear posture has entered an important new phase and that a public explanation is overdue," the experts said.

Pakistan may be producing 120-180 kg of HEU (Highly Enriched Uranium) per year, an amount sufficient for 7-15 warheads, they said, adding that the uranium ore is mined at several locations throughout Pakistan, with more mines scheduled to open in the future.

The revelation that Osama bin Laden was hiding for years in Abbottabad, only 16 km from a large military weapons depot with underground facilities, raised new questions about the security and control of Pakistan's nuclear weapons.

"Outside Pakistan, observers wondered if the nuclear arsenal was secure from potential terrorist theft; inside Pakistan, observers wondered whether the arsenal was safe from a possible United States or Indian incursion," the article said.

"Exactly how Pakistan safeguards its nuclear weapons, and what type of use-control features its weapons have, is unclear," they wrote, adding that the weapons are thought to have some basic use-control features to prevent unauthorised use.

"Its facilities and weapons are said to be widely dispersed in the country with most of the arsenal located south of Islamabad. Furthermore, the weapons are thought to be stored unassembled, with the cores separate from the weapons and the weapons stored away from the delivery vehicles," the report said.