North Korea’s Yongbyon Nuclear Complex: More Evidence the 5 MWe Reactor Appears to Have Restarted

Commercial satellite imagery of the Yongbyon Nuclear Scientific Research Center provides more evidence that operations at the 5 MWe Reactor have likely restarted. Consistent with a recent report by the International Atomic Energy Agency (IAEA), a discharge of cooling water into a new outflow channel leading into the Kuryong River is visible in satellite imagery from August 25. This has historically been one of the key indicators of reactor operations. However, unlike past intervals when the reactor was operating, no steam has been observed coming from the generator building.

Figure 1. Overview of reactor area.

Image Pleiades © CNES 2021, Distribution Airbus DS. For media options, please contact [email protected]

Figure 2. Close up of reactor outfall.

Image Pleiades © CNES 2021, Distribution Airbus DS. For media options, please contact [email protected]

This recent activity is the first indication of reactor operations since spring of 2018. Since then, traffic has consistently been observed in and around the reactor area, likely indicative of maintenance or other reactor start-up activities. Work has also been ongoing for several months on a dam in the Kuryong River to create a reservoir of water for the 5 MWe Reactor and Experimental Light Water Reactor (ELWR). This work appears to have been completed, although it will likely be tested by seasonal flooding in the coming weeks.

There have been no clear indicators yet that the ELWR has started operations.

At the same time, a series of images from early July to the present indicate that operations at the Thermal (Steam) Plant, supplying steam to the Radiochemical Laboratory for reprocessing activities, have ceased since early July. As noted in the IAEA report, the period of operations from mid-February to early July is consistent with the time needed to “reprocess a complete core of irradiated fuel from the 5MW(e) reactor.”

Figure 3. No visible smoke emission at Thermal Plant servicing the Radiochemical Laboratory.

Image Pleiades © CNES 2021, Distribution Airbus DS. For media options, please contact [email protected]
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