SEOUL • North Korea could be separating isotopes used to manufacture sophisticated and more powerful nuclear bombs, United States experts have warned, after Pyong-yang announced that its main atomic weapons complex was fully operational.
The head of North Korea's atomic agency said on Tuesday that all facilities at the Yongbyon nuclear complex - including a uranium enrichment plant and a 5-megawatt reactor seen as the country's main source of weapons-grade plutonium - had "started normal operations". He also claimed that North Korea was "steadily improving" its nuclear weapons in terms of "quality and quantity". The announcement came just hours after the chief of the national space agency hinted at a satellite rocket launch next month - seen by the US and its allies as a step towards the development of a nuclear-tipped intercontinental ballistic missile.
Both statements - accompanied by a routine threat that nuclear weapons could be used against the US at "any time" - were seen as military muscle-flexing for both domestic and international audiences.
At home, North Korea is planning a massive military parade to mark a key political anniversary on Oct 10, while Pyongyang's nuclear capabilities will feature high on the agenda of an expected summit later this month between the Chinese and US presidents.
The Washington-based Institute for Science and International Security said satellite imagery analysis was unable to confirm all Yongbyon facilities were fully functional, although there were multiple indications that the reactor and uranium enrichment plant were, at the very least, operating intermittently.
The institute also raised a red flag over what appeared to be a new "hot cell" facility under construction at Yongbyon, that could be dedicated to separating isotopes from irradiated material produced in the reactor. "The signatures visible through a historical analysis of satellite imagery are consistent with an isotope-separation facility, including tritium separation," the think-tank said yesterday.
Tritium is a key component in the design of more sophisticated thermonuclear weapons with far greater yields than those made of only plutonium and uranium.
North Korea has carried out three nuclear tests - in 2006, 2009 and 2013. The first two were plutonium devices, while the third was believed - though not confirmed - to have used uranium as its fissile material. "Whether North Korea can make nuclear weapons using tritium is unknown, although we believe that it remains a technical problem North Korea still needs to solve," the Washington-based think-tank said. "Solving this problem would likely require more underground nuclear tests," it added.
If, as has been widely speculated, North Korea pushes ahead with a rocket satellite launch to mark next month's 70th anniversary of the founding of the ruling Workers' Party, then the possibility of a fourth nuclear test would come into sharper focus.
North Korea's last rocket launch in December 2012 triggered a surge in military tensions that culminated in its third nuclear test just two months later.