China fears growing nuke threat

North Korea’s nuclear arsenal consists of about 20 warheads – twice as many as had been thought, according to Chinese experts.

The Stalinist state may also be able to produce another 20 weapons every year, giving it the ability to overtake Britain’s nuclear arsenal within a decade.

The assessment by Chinese Government experts was conveyed to American specialists during a meeting in Beijing in February. It charted how North Korea had progressed from testing a crude nuclear device in 2006 to building a fully functioning arsenal.

North Korea has reached the vital stage when it can manufacture nuclear warheads for delivery by short and medium-range missiles. In addition, the country’s scientists have mastered how to produce weapons-grade uranium and plutonium.

‘‘Some eight, nine or 10 years ago, they had the bomb but not much of a nuclear arsenal,’’ said Siegfried Hecker, a former head of the US nuclear laboratory at Los Alamos, who attended the meeting in Beijing. ‘‘I had hoped they wouldn’t go in this direction, but that’s what happened in the past five years.’’

Chinese experts believed North Korea had 20 nuclear warheads, Hecker told The Wall Street Journal. This compared with an estimate of 10 to 16 devices offered by the Johns Hopkins School of Advanced International Studies earlier this year.

China also believes North Korea has enough weapons-grade uranium in its stockpile – and the capacity to produce more of this material – to make another 20 warheads every year.

Britain’s nuclear deterrent consists of fewer than 160 deployed warheads. The latest estimate suggests that North Korea’s nuclear arsenal could be larger than Britain’s by 2022.

Mark Fitzpatrick, a nonproliferation specialist at the International Institute for Strategic Studies, said the Chinese estimates presented a ‘‘worrying’’ picture. ‘‘If true, it means that North Korea has more than the fledgling nuclear weapons programme we had assumed: it means they’ve made far greater strides than had been predicted.’’

One risk is that North Korea’s regime might sell a warhead to terrorists. ‘‘The more nuclear weapons they have, the more willing they may be to sell some to a willing buyer, particularly a terrorist group,’’ said Fitzpatrick.

Instead of selling a finished weapon, North Korea could choose to transfer weapons-grade uranium. The terrorists would then use this material to make their own device.

China is North Korea’s only ally, but China has opposed the regime’s nuclear ambitions and Beijing’s estimates could be unreliable.