The aim of the negotiations is to reconfigure the Iranian nuclear programme so that the international community can be confident it will not be used to build a warhead in secret, or so quickly that Iran becomes a nuclear-armed state before the rest of the world has time to react.
Until today such an option was a taboo subject among US government officials and their British counterparts, who have insisted Iran would be ultimately stopped from constructing a warhead.
At the lower figure, it would take Iran nearly a year to make a nuclear warhead, if it decided to do so.
They showed him the "perfect nuclear weapon", he wrote, "technologically more advanced than ours".To develop a credible nuclear threat, a country has to accomplish four tasks: obtain the explosive or fissile material; incorporate the explosives into a warhead small enough to fit on a long-range missile; build a long-range missile; and secure a platform to launch it from.
Bruce Bennett of the RAND Corporation, a think-tank, has tried to quantify the horror of a ten-kiloton warhead exploding in Seoul.
But the increasing tension with Russia over Crimea, China's more assertive territorial claims, Pakistan's growing arsenal of nuclear weapons, and the ongoing nuclear threat from an unstable North Korea mean such issues are no longer being left on the back burner.Right now, the NNSA's main concern is the production of "pits"—the hollow fissile core of a nuclear warhead.
Adopting two (or more) stages raises the output still further, while actually making the warhead more compact.
No one knows whether this collaboration has included warhead or other nuclear work too (though North Korea appears to have helped Syria to build a suspected and almost completed plutonium-producing reactor, which Israel destroyed in an air raid in 2007).Strutting its stuffNorth Korea is evidently quite happy to brandish its bombs.
They have plenty of evidence to suggest that Iran has done warhead development, besides other experiments whose purpose can only be to build a nuclear weapon, or enable one to be assembled at speed.But Iran refuses to answer their questions, and now threatens to increase its enrichment effort tenfold.
Sandwiched between hard plates, they discharge a rapidly expanding gas to absorb energy from a warhead.
On procurement, complex, politically driven multinational programmes that are bedevilled by demands for all the parties to share in the work, such as the Eurofighter Typhoon, could make way for simpler, bilateral projects.There are even discussions about Britain sharing in France's nuclear-warhead simulation testing facilities, rather than replicating them at huge cost.
