Yongbyon Nuclear Plant

Henri Fernandez
March 13, 2017

Submitted as coursework for PH241, Stanford University, Winter 2017


Fig. 1: The Yongbyon 5MWe Nuclear Reactor. (Source: Wikimedia Commons)

The Yongbyon Nuclear Scientific Research Center was built just north of Pyongyang, Democratic People's Republic of Korea in the 1980s. The Yongbyon site is the major nuclear facility in North Korea. [1] The sight is known for its October 6, 2006 nuclear test that sparked fear all around the world. [2] Before being shut down as part of the 6PT program to halt North Korean weaponry, it is reported that the reactor produced enough weapons-grade plutonium for North Korea's arsenal of eight to twelve nuclear weapons. [1]

Yongbyon Site

The Yongbyon site was home to a large nuclear weapons test in 2006. [1] However, in 2007, an agreement was reached with the 6PT to shutdown the Yongbyon site. North Korea officials complied with the 6PT agreement to shutdown the plant in 2008, by destroying the large and visible cooling tower at the plant. [3]

In April 2013, North Korea announced their plans to reopen the reactor in Yongbyon. An analysis of the satellite images from August 2013 showed that the plant was likely running again. [1] Analysts say that the reason for the plant shut down is unknown, but claim that North Korea will unlikely remove the entire core reactor in Yongbyon. Analysts presume that the shutdown was probably caused by partial refueling, maintenance, or renovating the reactor in Yongbyon. [1]

Even though much of the components of the Yongbyon Site are not known to the public, in January 2004, Stanford University professor Siegfried S. Hecker and his colleagues traveled to Pyongyang, North Korea to tour the Yongbyon facility with the director of the site, Ri Hong Sop. [2] They toured the three main components of the facility that include the 5 MWe reactor, the spent-fuel storage pool, and the plutonium repossessing facility. [2]

The most major installation of the Yongbyon site is the 5 MWe reactor which has been operating since 1986. An image of the reactor can be seen in Fig. 1. The 5 MWe reactor could have produced enough plutonium for five or six bombs and it is speculated that some of the fuel from the reactor has been used for reprocessing. [4] At the time of Professor Hecker's visit, the 5 MWe reactor was operating by with some restrictions. It was operating at 25 MWt (thermal power), but the output temperatures have been reduced from 350 degrees Celsius to 300 degrees Celsius. He noted that the lower temperature creates higher weapons-quality plutonium, but reduces efficiency of the power output. [2] With respect to the fuel fabrication facility, the Yongbyon director stated that they expect to begin new fuel fabrication in 2007, and it will take them a year to fabricate fuel rods. Concerning the Reprocessing facility and the plutonium metal production, the Yongbyon director said that they decided to postpone the waste treatment activity to 2006. [2]


The Yongbyon Nuclear Scientific Research Center has been at the center of North Korean nuclear weapon development. [2] In this report, we have gotten an overview of the nuclear site, while also learning about its components. Looking forward it will be interesting to follow the future developments of the site that is at the core of North Korea's nuclear weapon program.

© Henri Fernandez. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] K. Davenport, "Images Suggest N. Korea Reactor Shutdown," Arms Control Today 44, No. 9, 35 (November 2014).

[2] S. S. Hecker, "Report on North Korean Nuclear Program," Center for International Security and Cooperation, Stanford University, 15 Nov 06.

[3] G. J. Moore, "America's Failed North Korea Nuclear Policy: A New Approach," Asian Perspect. 32, No. 4, 9 (2008).

[4] A. Mack, "The Nuclear Crisis on the Korean Peninsula," Asian Surv. 33, 339 (1993).