North Korea’s Yongbyon Nuclear Facility: Operations Resume at the 5 MWe Plutonium Production Reactor

A 38 North exclusive with analysis by Jack Liu and Joseph S. Bermudez Jr.

New commercial satellite imagery indicates that operations at the 5 MWe plutonium production reactor located at North Korea’s Yongbyon Nuclear Scientific Research Center has likely resumed. Analysis from January 18 showed signs that Pyongyang was preparing to restart the reactor after spent fuel rods had previously been unloaded for a reprocessing campaign that produced additional plutonium for its nuclear weapons stockpile. Imagery from January 22 shows a water plume (most probably warm) originating from the cooling water outlet of the reactor, an indication that the reactor is very likely operating.

Figure 1. Close-up of the 5MWe Reactor on January 16.

Figure 2. Water plume originating from the 5Mwe Reactor cooling water outlet.

Currently, most of the river is frozen over except where this water mixes with the river. Currents carry this mix downstream—visible as a plume of ice-free water. Without being able to measure the water temperature rise or water flow from the reactor, it is impossible to estimate at what power level the reactor is running, although it may be considerable.

Figure 3. Close-up of 5MWe cooling water outlet and ice-free plume.