Feb. 8 (UPI) -- North Korea could have about 100 pounds of plutonium and 600 pounds of highly enriched uranium in its arsenal, a South Korean analyst said Thursday, local time.
Lee Sang-hyun, a chief researcher at the Sejong Institute, a South Korean think tank, said at a conference in Seoul North Korea could have been secretly producing highly enriched uranium, or HEU, while staying relatively undetected, Yonhap reported.
HEU can be produced in small-scale facilities, unlike plutonium that requires larger stations like nuclear reactors, Lee said.
Lee said his findings indicate North Korea can produce about 13 pounds of plutonium annually, while its cache of HEU increases by 176 pounds every year.
The South Korean researcher said it typically takes 4-13 pounds of plutonium to produce a nuclear warhead, and 33-44 pounds of HEU to make a similar payload.
"North Korea appears to have used HEU in its fifth nuclear test [last September], and the demonstration of a relatively strong explosive power can mean the country has produced enough HEU," Lee said.
The amount of fissile material in North Korea's possession means it is at an advantage when miniaturizing nuclear warheads. The country can produce more nuclear weapons with smaller quantities of nuclear material, the researcher said.
Lee said "pressure diplomacy" must be strengthened while making it known to the North the objective is not the collapse or the removal of the regime.
Park Byung-kwan, a director at government-run Institute for National Security Strategy, said he is concerned about the "void in South Korean leadership."
Park also said North Korea could go ahead with the test-launch of a long-range missile if Pyongyang decides it did not make a breakthrough in U.S.-North Korea relations with the new Trump administration.
North Korea has previously requested a peace treaty from the United States, and recognition as a nuclear weapons state.