North Korea appears to be close to operating an experimental light water reactor at its Yongbyon Nuclear Scientific Research Center.

U.S.-based North Korea monitoring Web site 38 North made the assessment on Monday based on commercial satellite imagery from February eleventh. 

The report said the reactor, having been under construction since 2010, seems to be nearing operational status. It cited improvements made over the past year, including new provisions for a more consistent cooling water supply, installation of internal equipment and the connection of the reactor to the local electrical grid.

The report added that the latest imagery from February eleventh shows the reactor is externally complete.

The site said that “among the most notable changes over the past year is the construction of an earthen dam with a sluiceway across the Kuryong River” which was constructed just downriver below the second cistern in late December 2017 into January 2018.