Yongbyon (Nyongbyon)

North Korea, according to a report 15 May 2022 by CNN, had restarted construction on a nuclear reactor that could increase its production of plutonium for nuclear weapons by a factor of ten. Citing satellite images and a source familiar with U.S. intelligence, CNN reported over the weekend that the reactor in question, at the North's nuclear facility at Yongbyon, is under construction again work having stopped initially in 1994. Officials, the report said, say the North is not trying to hide the work. This reactor has a capacity of 50 megawatts, while the other one, active since the 1980s, is 5 megawatts. A weapons expert, Jeffrey Lewis at the Middlebury Institute, told CNN that the images show the North is working on the reactor's cooling loop, which would explain other activities seen at the site in recent years.

Commercial satellite imagery released by the U.S.-Korea Institute at Johns Hopkins University 03 June 2013 suggested North Korea was finishing interior work on a 20-30 megawatt [electric] experimental light-water reactor that could be operational in nine-12 months. The North had said the light-water reactor will generate electricity for civilian purposes. However, the U.S. is concerned it could also be used to make the weapons-grade plutonium that North Korea is believed to have used in past nuclear tests.

50-MW(e) Reactor

North Korea apparently began constructing a 50-200MW reactor at Yongbyon sometime in the 1984-1985 timeframe. Some reports suggested that US intelligence did not detect this reactor construction until the project was already half complete. In June 1988, US satellite imagery reportedly showed a 50MW reactor under construction at Yongbyon. In early 1989, US imagery intelligence satellites reportedly detected construction activity of additional nuclear-related facilities at Yongbyon. These facilities included a research center, housing complex, nuclear detonation test site, a third reactor (initially estimated at between 50-200MW), and a reprocessing facility.

The 50-megawatt (electric) reactor would have produced enough plutonium for North Korea to build an additional 7-10 nuclear weapons per year. This reactor was expected to be completed in 1995. With this schedule, all of the reactor's equipment and components, including the reactor's graphite blocks and fuel-handling machines, should have been available for inclusion in the reactor's building. Instead, North Korea eventually informed IAEA that it had manufactured only about 50 percent of the graphite blocks needed for the 50-MW(e) reactor and none of the graphite blocks needed for the 200-MW(e) reactor at Taechon. According to IAEA, North Korea explained that there was no reason for it to continue manufacturing equipment and components for the 2 reactors after July 1993, since it had begun discussions with the United States about replacing the graphite-moderated reactors with light-water reactors. However, North Korea's explanation was insufficient for IAEA to rule out whether any additional nuclear equipment and components exist.

The 2 higher power reactors under construction at Yongbon and Taechon were expected to yield another 200 kilograms of plutonium annually, enough plutonium for about 50 atomic bombs per year. The reactor facilities reportedly were not attached to a power grid, increasing concern that the facilities were intended to produce material for making nuclear weapons rather than for producing electricity.

On 08 January 2004, an unofficial American delegation visited North Korea and the Yongbyon complex. The North Koreans stated to the delegation that construction of the 50 MWe reactor stopped in 1994. They stated that at that time it was within one year of completion. Nothing had been done since. At the time of the delegation's visit the North Koreas stated that they were evaluating what to do with the reactor. The US delegation drove past the 50 MWe reactor site twice. They confirmed that there was no construction activity at this site and that there were no construction cranes on site. The reactor building appeared to the Americans to be in a terrible state of repair. The concrete building structure showed cracks. The steel exhaust tower was heavily corroded, as was other steel equipment on the site. The building was not closed up and resembled a deserted structure. The Americans concluded that the reactor was much more than one year from completion now, and that it was not clear how much of the existing structure could have been salvaged.

Stanford professor John Lewis, an expert on Northeast Asian security issues, made his 11th visit to North Korea in late May 2005. At that time the North Koreans told him that they had restarted construction of the 50 MWe and 200 MWe reactors that had been frozen under the 1994 Agreed Framework. As reported on 6 June 2005 by Knight Ridder, the North told Lewis they planned on finishing the reactors within 2 years. On 15 June 2005 Kyodo News reported that North Korea had informed a visiting American scholar in late May 2005 that it had resumed the construction of the 2 nuclear reactors that was halted under the 1994 Agreed Framework. According to this report, US Government sources stated on background that this information had already been communicated to the US government. The 2 reactors could produce about 275 kilograms of plutonium annually, enough for about 50 atomic bombs.

On 30 June 2005, Japan's Nihon Keizai Shimbun reported an American source claimed that North Korea had resumed construction work on the 50MWe reactor at Yongbyon and the 200 MWe reactor at Taechon. Work on these facilities had been halted under the 1994 Agreed Framework with the US. The report claimed that the North had recently informed the US government that it had resumed construction of the reactors. The activities were said to be on a scale easily detected by satellite. The sources said above-ground work had begun on a 50 MWe reactor in Yongbyon, while the ground was being leveled for a 200 MWe reactor in Taechon.

According to reports, a South Korean source claimed that there was no information indicating the North had resumed construction. In a news briefing, Japanese Chief Cabinet Secretary Hiroyuki Hosoda (also rendered Hirouki Hosoda), stated that he could not confirm the resumption of reactor construction, though he acknowledged that North Korea had previously indicated plans to restart the project.

If renewed activity was confirmed, it was regarded by South Korean, Japanese, and American observers as a provocation to gain leverage in the process of resuming the Six-Party Talks. The move would not immediately increase North Korea's nuclear capacity, since several years would have been required to complete the reactors.