A U.S. nuclear expert projects North Korea could be able to extract eight kilograms of weapons-grade plutonium from its used fuel rods by October.

In an article in the Bulletin of the Atomic Scientists, Stanford University professor Siegfried Hecker said reprocessing all of the eight-thousand fuel rods at the North's five megawatt Yongbyon reactor could be possible in six months.

He also predicted that given the number of unspent fuel rods North Korea has in store, the country could, in the next few years, produce as much as an additional six kilos of plutonium, which would be enough to make one nuclear weapon per year.

North Korea recently declared that it plans to resume its nuclear activities in response to the U.N.’s adoption of a statement denouncing the North for its April fifth rocket launch.