North Korea is believed to have shut down its sole plutonium-producing nuclear reactor either for refueling or maintenance purposes, a U.S. think tank said Sunday, citing commercial satellite imagery.
The Institute for Science and International Security (ISIS) said it reached the decision based on the absence of two key indicators of operations at the 5-megawatt reactor: steam venting from the reactor and cooling water discharge from it.
"In imagery dated Aug. 27 and Sept. 29, 2014, both these signatures are missing," ISIS said in a report authored by David Albright, a nuclear expert and chief of the institute, and another researcher, Serena Kelleher-Vergantini.
"ISIS assesses that it is possible that the reactor is partially or completely shut down," it said.
It is unclear what exactly led to the shutdown, but the North could be carrying out a partial refueling of the reactor's core if some fuel rods are defective, the institute said. A total core refueling is unlikely because the reactor has only been running for a year, it said.
The institute also said the North could have shut down the reactor for maintenance or renovation purposes. Satellite images show unidentified activity taking place on the roof of the reactor's turbine building, it said.
The reactor at the North's main Yongbyon nuclear complex has been the source of weapons-grade plutonium for the communist nation. The small reactor is capable of producing spent fuel rods which, if reprocessed, could give the regime enough plutonium to make one bomb a year.
Plutonium from the reactor was used in at least two of the three nuclear tests the North has conducted.
Separately from the 5-megawatt reactor, the North has also been building a larger-scale light water reactor at Yongbyon that experts say could give Pyongyang enough plutonium to make about five or six weapons a year.
ISIS said that the start-up date of the light water reactor still remains unclear.
"Satellite imagery shows no signs of activity or even movement of objects at the site. However, activity may be occurring inside the building; and some foreign procurements continue for this reactor. Thus, North Korea is expected to operate this reactor at some point," it said.
The institute said the North is believed to be working on a project to expand its uranium-enrichment centrifuge plant at its Yongbyon complex as the latest imagery shows activity renovating the roof of a building adjacent to the centrifuge plant.
"It is likely that North Korea has installed centrifuge cascades inside the new section of the centrifuge building," it said. "However, it cannot be determined whether North Korea has finished the expansion of this centrifuge plant." (Yonhap)
The Institute for Science and International Security (ISIS) said it reached the decision based on the absence of two key indicators of operations at the 5-megawatt reactor: steam venting from the reactor and cooling water discharge from it.
"In imagery dated Aug. 27 and Sept. 29, 2014, both these signatures are missing," ISIS said in a report authored by David Albright, a nuclear expert and chief of the institute, and another researcher, Serena Kelleher-Vergantini.
"ISIS assesses that it is possible that the reactor is partially or completely shut down," it said.
It is unclear what exactly led to the shutdown, but the North could be carrying out a partial refueling of the reactor's core if some fuel rods are defective, the institute said. A total core refueling is unlikely because the reactor has only been running for a year, it said.
The institute also said the North could have shut down the reactor for maintenance or renovation purposes. Satellite images show unidentified activity taking place on the roof of the reactor's turbine building, it said.
The reactor at the North's main Yongbyon nuclear complex has been the source of weapons-grade plutonium for the communist nation. The small reactor is capable of producing spent fuel rods which, if reprocessed, could give the regime enough plutonium to make one bomb a year.
Plutonium from the reactor was used in at least two of the three nuclear tests the North has conducted.
Separately from the 5-megawatt reactor, the North has also been building a larger-scale light water reactor at Yongbyon that experts say could give Pyongyang enough plutonium to make about five or six weapons a year.
ISIS said that the start-up date of the light water reactor still remains unclear.
"Satellite imagery shows no signs of activity or even movement of objects at the site. However, activity may be occurring inside the building; and some foreign procurements continue for this reactor. Thus, North Korea is expected to operate this reactor at some point," it said.
The institute said the North is believed to be working on a project to expand its uranium-enrichment centrifuge plant at its Yongbyon complex as the latest imagery shows activity renovating the roof of a building adjacent to the centrifuge plant.
"It is likely that North Korea has installed centrifuge cascades inside the new section of the centrifuge building," it said. "However, it cannot be determined whether North Korea has finished the expansion of this centrifuge plant." (Yonhap)
