Nuclear security

North Korea’s Yongbyon Nuclear Research Center: Construction Progressing Rapidly Near Reactors; No Signs of Reprocessing

Commercial satellite imagery of the Yongbyon Nuclear Scientific Research Center from April 4 shows significant progress in the modifications underway associated with the 5 MWe reactor’s secondary cooling system. (Figure 1) Over the past five days, a rectangular, concrete-walled, vault-like foundation has been erected.[1] (Figures 2 and 3) The purpose of this new structure remains unclear, but it could be for a new pump house comparable to the one serving the ELWR. Given recent efforts to dam the river below this point to create a reservoir, this could be part of a larger effort to provide a steady flow of water into that reactor allowing it to run more continuously and safely in the future. Alternatively, since its location is near where the reactor cooling water used to be expelled during previous reactor operations, it could be part of a new cooling water outflow system to enhance the overall efficiency and potentially the cooling capacity of the secondary cooling loop.