North Korea has restarted production of plutonium fuel, a senior State Department official said on Tuesday, showing that it plans to pursue its nuclear weapons program in defiance of international sanctions.
The U.S. assessment came a day after the U.N. nuclear watchdog said it had “indications” that Pyongyang has reactivated a plant to recover plutonium from spent reactor fuel at Yongbyon, its main nuclear complex.
The latest developments suggest North Korea's reclusive communist government is working to ensure a steady supply of materials for its drive to build warheads, despite tightened international sanctions after its fourth nuclear test in January.
The U.S. official, who spoke on condition of anonymity, said that Washington is worried by the new plutonium reprocessing effort, but he offered no explicit word on any U.S. response.
International Atomic Energy Agency chief Yukiya Amano told a news conference in Vienna on Monday that there have been indications of renewed plutonium reprocessing activities at Yongbyon. Reprocessing involves extracting plutonium from spent reactor fuel, one route to obtaining bomb fuel other than uranium enrichment.
Experts at the U.S.-Korea Institute at Johns Hopkins University's School of Advanced International Studies in Washington predicted last year that North Korea's nuclear weapons stockpile could grow to 20, 50 or 100 bombs within five years, from an estimated 10 to 16 weapons at that time.North Korea has come under tightening international pressure over its nuclear weapons program, including tougher U.N. sanctions adopted in March backed by its lone major ally China, following its most recent nuclear blast and ballistic missile tests.