IX. North Korea's military nuclear capabilities

WORLD NUCLEAR FORCES 449 IX. North Korea’s military nuclear capabilities SHANNON N. KILE AND HANS M. KRISTENSEN The Democratic People’s Republic of Korea (DPRK or North Korea) maintains an active but highly opaque nuclear weapon programme. It is estimated that North Korea may potentially have produced 10–20 nuclear weapons (see table 11.10). This is based on calculations of the amount of plutonium that North Korea may have separated from the spent fuel produced by its 5 megawatt-electric (MW(e)) graphite-moderated research reactor at the Yongbyon Nuclear Scientific Research Centre and assumptions about North Korean weapon design and fabrication skills. North Korea is believed to be increasing its limited holdings of weapon-usable plutonium (see section X), although assessments differ about the scale and pace of the increase.1 When fully operational, the 5-MW(e) reactor at Yongbyon has been estimated to produce approximately 6 kilograms of plutonium per year, enough for one nuclear weapon.2 However, the operational status of the reactor since its announced restarting in 2013 has been unclear. Commercial satellite imagery and thermal imagery indicate that the reactor might be operating at low power or only intermittently.3 In August 2016 North Korea confirmed assessments made by the International Atomic Energy Agency (IAEA) and several non-governmental analysts earlier in the year that it was conducting a new spent fuel reprocessing campaign at the Yongbyon radiochemical laboratory.4 In 2016 North Korea publicly acknowledged that it was producing highly enriched uranium (HEU) for nuclear weapons.5 There has been considerable speculation that North Korea is seeking to build warheads using HEU as the fissile material in order to overcome the constraints imposed by its limited holding of separated plutonium. However, it is not known whether it has --- 1 See e.g. Yonhap News Agency, ‘North Korea has 50 kg of weapons-grade plutonium: Seoul’s defense white paper’, 11 Jan. 2017; and Albright, D. and Kelleher-Vergantini, S., ‘Plutonium, tritium and highly enriched uranium production at the Yongbyon nuclear site’, Insititute for Science and International Security, Imagery Brief, 14 June 2016. 2 Hansen, N. and Lewis, J., ‘North Korea restarting its 5 MW reactor’, 38 North, US–Korea Institute, Johns Hopkins University, 11 Sep. 2013. The 5-MW(e) reactor at Yongbyon operated between 1986 and 1994, and between 2003 and 2007. The reactor was then shut down and disabled pursuant to an agreement reached in the Six-Party Talks. It was restarted in 2013. 3 Bermudez, J. and Dinville, A., ‘Checks and balances: thermal imagery analysis of Yongbyon’, 38 North, US–Korea Institute, 25 Oct. 2016. 4 Kyodo News Agency, ‘North Korea confirms restart of plutonium processing’, Japan Times, 17 Aug. 2016; and Reuters, ‘North Korea apparently reopened plant to produce plutonium: IAEA’, 16 June 2016. 5 Kyodo News Agency (note 4).