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Images Suggest N. Korea Reactor Shutdown
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November 2014

By Kelsey Davenport

Satellite images suggest that North Korea may have shut down a nuclear reactor that has been a key part of the county’s nuclear weapons program, according to an analysis by a Washington think tank.

In an Oct. 3 brief, David Albright and Serena Kelleher-Vergantini of the Institute for Science and International Security wrote that images of the Yongbyon site from August and September show that there is no longer steam venting from the reactor or water being discharged from the secondary cooling system. These observations led the two analysts to conclude that the reactor may have been shut down “possibly for either partial refueling or renovations.”

Steam and water discharge are typical indications that a reactor is operating. These signatures were present in past satellite images that the authors analyzed in April and June.

North Korea has not issued any statement on the operational status of the reactor, but a spokesman for the National Peace Committee of Korea said on Oct. 7 in Pyongyang that the North Korean government was continuing to “bolster its nuclear deterrent.”

The reactor produces plutonium, which, when separated, can be used for nuclear weapons. Built in the 1980s, the reactor was shut down and disabled in 2007 as a part of Pyongyang’s negotiations over its nuclear weapons program with six countries, including the United States. Before being shut down, the reactor produced enough weapons-grade plutonium for North Korea’s estimated arsenal of eight to 12 nuclear weapons.

In April 2013, North Korea announced its intention to restart the reactor. (See ACT, May 2013.) Analysis of satellite images from August 2013 indicated that the reactor was likely operational again. (See ACT, October 2013.)

Albright and Kelleher-Vergantini said the reason for the shutdown is unknown but it is unlikely that North Korea is removing the entire core of the reactor. Cores typically last several years, but a partial refueling could have caused the shutdown, the authors wrote. North Korea could also be performing maintenance on or renovating the reactor, they said.

If the reactor was shut down for any of these reasons, it is likely that North Korea will restart it in the future, Albright and Kelleher-Vergantini said.

Satellite imagery from September also shows that North Korea has completed an upgrade to the Sohae Satellite Launching Station, Nick Hansen said in an Oct. 1 piece published by 38 North, a website run by the U.S.-Korea Institute at Johns Hopkins University.

Hansen, a former military imagery analyst, wrote that satellite images of the Sohae site show the completion of a “major construction program” that began in early 2013, including an upgrade of the launch pad. The upgrade will enable North Korea to launch rockets that are larger than the Unha-3 satellite launch vehicle, Hansen said. North Korea launched two Unha-3 rockets, which have three stages and are liquid fueled, from the Sohae facility in 2012.

Citing modifications that increased the height of the tower and widened the access road to the launch, Hansen said rockets that are up to 50 meters tall can now be launched from the site. The Unha-3 is about 32 meters tall.

There is no evidence of preparations for another rocket launch, Hansen wrote, but North Korea is “ready to move forward” and could launch a rocket by the end of 2014 if it chose to do so.

Hansen also said the satellite images indicate the completion of several other construction projects at the site, such as new roads, a railroad spur to the main launch pad, and an underground data cable network that links the major facilities at the site.