The U.S.-based North Korea-focused outlet 38 North said on the 23rd that North Korea is carrying out upgrade work at the Yongbyon Nuclear Scientific Research Center, a key nuclear facility, including installing equipment believed to be heat exchangers.
Analyzing commercial satellite images taken from last month to this month, 38 North found modernization and expansion work across the Yongbyon nuclear complex.
At the building northeast of the Radiochemical Laboratory (RCL) in the research complex, which had been presumed to be a new uranium enrichment facility, additions such as a passage connecting a garage and the building were made, and concrete paving around the building was completed.
In satellite photos taken in June, the building, captured in an unfinished state, is a two-story structure that is estimated to have a floor area of 5,640 square meters per floor.
In the latest satellite images, six pieces of equipment that appear to be heat exchangers were also seen installed at the building. Heat exchangers are used to cool the centrifuges needed for uranium enrichment and to maintain the internal temperature of the building.
38 North also said satellite images of the Yongbyon nuclear complex showed continued operation of the 5-megawatt (MW) reactor and trial runs in a pre-operational phase of the experimental light-water reactor, adding that all such activities align with Kim Jong-un, chairman of the State Affairs Commission of North Korea, and his demand to strengthen nuclear forces.
Kim, the chairman of the State Affairs Commission, visited a nuclear material production base this year and said, "We must overfulfill the plan to produce weapons-grade nuclear material and strengthen the country's nuclear shield," calling for a buildup of nuclear forces.