N Korea may have 21 nukes or more: US think tank

The Institute for Science and International Security (ISIS) based the estimates on the amounts of weapons-grade plutonium and highly enriched uranium the North is believed to have produced at its Yongbyon nuclear complex.

The report came after International Atomic Energy Agency (IAEA) chief Yukiya Amano said last week that North Korea might have reactivated a plant at Yongbyon for reprocessing plutonium for use in nuclear weapons. In late 2014, ISIS estimated the North’s nuclear arsenal at 10 to 16 weapons.

Since then, the North has added another four to six weapons to the stockpile for a total of 13 to 21 or more on Wednesday, ISIS said. The 13-21 estimate did not take into account the additional contribution of a possible second centrifuge plant the North may have built to produce weapons-grade uranium, it said.

“Nonetheless, this exercise, despite not being comprehensive, shows that North Korea could be significantly increasing its nuclear weapons capabilities”, the Washington-based think tank said. Most of this increase since 2014 can be attributed to the production of weapons-grade uranium, it added.

Amano, citing satellite imagery, said last week in Vienna: “The indications that we have obtained... (are of) activities related to the five-megawatt reactor, expansion of enrichment facilities and activities related to (plutonium) reprocessing.”