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Megan Khalife, Gabriel Helupka, Magdalena Breyer, Kiara Alexander, Mateo Maya

Elena Rossetti, Senior Editor

January 17, 2024

Yongbyon Located in the North Pyongan Province Highlighted in Red[1]

Key judgments  

North Korea’s Yongbyon Nuclear Scientific Research Centre will very likely continue undergoing construction efforts to advance the country’s nuclear fuel and weapon manufacturing capabilities. The operationalization of the new light water reactor (LWR) to increase plutonium production and the potential advancement in North Korea’s nuclear arsenal will almost certainly increase tensions in the Korean Peninsula and lead to continued global scrutiny. The international community will very likely implement additional sanctions to maintain its diplomatic efforts aimed at denuclearization, with neighboring countries very likely reassessing their conventional and nuclear security postures through the enhancement of their military and defensive strategies. This study analyzes observable developments at the Yongbyon nuclear complex over the past two years using geospatial-intelligence (GEOINT) tools like Google Earth and the Copernicus Programme’s Sentinel-2 satellite. GEOINT tools combined with available open-source reporting foster the analysis of strategic implications for the LWR’s integration into North Korean nuclear ambitions. The study analyzes the implications of increased plutonium production for nuclear armament, North Korea's efforts to conceal such activities, and the subsequent geopolitical impacts on global and inter-Korean nuclear nonproliferation efforts. Google Earth and Sentinel-2 provide historical evidence of observable changes to the complex’s terrain, construction efforts, operational changes, and LWR developments.

Tracking the changes in North Korea's nuclear development in Yongbyon 

  • Region and focus of the study: This report examines operational and strategic changes to North Korea’s Yongbyon nuclear complex, located in the North Pyongan Province, highlighting ongoing construction activities and renovations and their potential uses to advance the country’s nuclear weapons program. North Korea established the Yongbyon Nuclear Scientific Research Centre in 1961 through agreements with the Soviet Union to bolster the country’s military mission of producing fissile material for its nuclear weapons. The complex includes reactors and assets, notably the IRT-2000 reactor, the five-megawatt (5MW) reactor, the experimental LWR, the uranium enrichment facility, and the plutonium reprocessing center.[2] This report primarily focuses on the LWR, which North Korea founded in 2010 for electricity production and remained externally complete with no evidence of operations.

  • North Korea's nuclear program and nonproliferation activities: North Korea initially ratified the Nuclear Nonproliferation Treaty (NPT) in 1985 but withdrew in 2003, emphasizing self-defense against perceived threats from the US.[3] During an April 2003 trilateral meeting between China, the US, and North Korea, the country revealed that it possesses nuclear weapons publicly for the first time. In 2005, following multiple rounds of the Six-Party Talks that started in 2003 between China, Russia, Japan, the US, South Korea, and North Korea, the country agreed to several concessions. These concessions included abandoning nuclear weapon production efforts, allowing monitoring by International Atomic Energy Agency (IAEA) inspectors in exchange for food and energy assistance, and rejoining the NPT.[4] Despite asserting peaceful nuclear intentions, North Korea has since conducted six nuclear tests, with the UN Security Council (UNSC) imposing sanctions on the country to curb its nuclear weapons development program.[5] In 2009, North Korea ejected IAEA inspectors, forcing Western nations and nuclear monitors to rely only on satellite imagery from geospatial intelligence.[6] Operations at Yongbyon increased significantly following failed discussions between the US and North Korea at the 2019 Hanoi Summit, which aimed to negotiate the denuclearization of the Korean Peninsula.[7] 

  • Investigative focus: The LWR is capable of producing plutonium, one of the primary fuels for nuclear weapons. On December 21, 2023, the IAEA reported that North Korea likely started operating the Yongbyon LWR in a possible attempt to produce nuclear-capable bomb fuel. The IAEA observed heightened levels of activity at and around the Yongbyon complex consistent with LWR commissioning.[8]

  • Affected points:

 Image of the Yongbyon Nuclear Complex, October 13, 2019[9]

 Image of the Yongbyon Nuclear Complex, September 19, 2022[10]

  • Patterns between affected points:

 Image of the Yongbyon Nuclear Complex, February 24, 2023[16]

Image of the Yongbyon Nuclear Complex, January 10, 2024[17]

Secondary Source Analysis

Activities at Yongbyon increased substantially following the US and North Korea’s failure to reach an agreement at the 2019 Hanoi Summit, as the construction activities in Yongbyon city and the nuclear center.[18] The continued residential growth of the town almost certainly proves the North Korean government’s permanent commitment to sustain and increase its nuclear power.

Satellite imagery indicates that the plutonium production restarted in February 2021, with the reactivation of the thermal plant’s noticeability.[19] Imagery from August 2021 verified this conclusion through the observable discharge of cooling water into the Kuryong River, likely evidence for a new uranium core of the 5MW reactors and its active production of plutonium.[20] Thermal infrared satellite imagery from January 2022 showed that water in proximity to the 5MWe reactor’s cooling discharge pipe was thawed.[21] 

Regarding uranium production, the discernment of snowmelt on multiple buildings, including the uranium hexafluoride feed used for uranium and nuclear fuel production, in February 2022 provided evidence of the likely operation of the facility.[22] Between February and September 2023, commercial satellite imagery confirmed ongoing renovation activities of the uranium conversion facilities and the erection of new buildings nearby,[23] almost certainly indicating North Korea’s plans to expand its uranium production capacities. Renovations appear to be complete, with the new buildings nearing completion.[24]

Indicators for the further operability of the Yongbyon nuclear installations are recent activity in the LWR, which has been under construction since 2010, and the continuing developments on long-range delivery systems. The IAEA will very unlikely be able to determine the operability and capabilities of the LWR without entering the facilities.[25] There is a roughly even chance North Korea will have maintenance and safety issues on its facilities without the IAEA’s assistance and monitoring. Unmonitored safety protocols will likely generate an environmental impact like water containment, especially in the cooling systems’ water sources. North Korea is very likely building up its military capabilities, with a focus on nuclear weapons, satellites, and attack drones. According to Kim Jong Un, further military development will expand North Korea´s offensive and deterrence capabilities.[26] North Korea will very likely develop its satellite systems capabilities to combine them with its nuclear capabilities, likely intensifying its nuclear testing in the Yongbyon complex. North Korea will likely invest in satellite and long-range communications programs to support its nuclear infrastructure and systems.


North Korea’s growing capacity for plutonium production very likely heightens geopolitical tensions and introduces new challenges in addressing the country’s nuclear ambitions. The Counterterrorism Group (CTG) recommends that the international community acknowledge gaps in diplomatic strategies and mechanisms intended to curb nuclear proliferation. The IAEA should consider enforcing restrictions and monitoring North Korea’s nuclear activities, as the direct access to North Korea’s Yongbyon Nuclear Scientific Research Centre and reliance on satellite imagery will very unlikely to assist in confirming the operational status of the LWR and delay understanding the full scope of the facility’s nuclear development. Gaps in the study include the limited real-time Google Earth data as the latest images date to October 2022, along with likely North Korean concealment efforts of the facility from a satellite view. Weather impacted the visibility of the complex on several dates in December 2023 and January 2024. Future research areas could include analysis of nuclear production capabilities and utilization of measurement and signature intelligence (MASINT) to analyze the acoustics of future North Korean missile tests. Research can also use thermal and infrared analysis of the Yongbyon facility to determine continued activity or water discharge from the LWR.      


[2] Yongbyon: The heart of North Korea's nuclear programme, BBC, February 2019,

[3] North Korean Nuclear Negotiations, Council on Foreign Relations,

[4] North Korea’s Nuclear Weapon Program: A History, Columbia Law School: Center for Korean Legal Studies, 

[5] North Korean Nuclear Negotiations, Council on Foreign Relations,

[6] Reactor at North Korean nuclear site likely to be operational this summer, The Asahi Shimbun, December 2023, 

[7] Trump, Kim end summit with standoff over easing US sanctions, AP, February 2019, 

[8] North Korea appears to be looking to make more bomb fuels at its main nuclear facility, experts say, AP, December 2023, 

[9] Gabriel Helupka via Google Earth

[10] Ibid

[11] Growing Activity at North Korea’s Experimental Light Water Reactor, 38 North, April 2023, 

[12] Progress at North Korea’s Experimental Light Water Reactor at Yongbyon, 38 North, February 2018,

[13] Second North Korean nuclear reactor appears to be operational, IAEA says, Reuters, December 2023,

[14] Kim calls South Korea a principal enemy as his rhetoric sharpens in a US election year, AP, January 2023, 

[15] North Korea halts radio broadcasts, curbs exchanges with South -Yonhap, Reuters, January 2024, 

[16]Sentinel Playground,, Sinergise Ltd. Modified Copernicus Sentinel data 2024/Sentinel Hub.

[17] Ibid

[18] North Korea’s Yongbyon Nuclear Research Center: Upgrades Around the Complex, 38 North, May 2022, 

[19] Ibid

[20] North Korea’s Yongbyon Nuclear Complex: More Evidence the 5 MWe Reactor Appears to Have Restarted, 38 North, August 2021, 

[21] Thermal Imagery Analysis of Continued Activity at Yongbyon, CSIS: Beyond Parallel, February 2022, 

[22] North Korea’s Yongbyon Nuclear Center: In Full Swing, 38 North, March 2022, 

[23] Yongbyon Nuclear Scientific Research Center: An Overview of Changes at the Uranium Enrichment and Conversion Facilities, 38 North, November 2023, 

[24] Ibid

[25] IAEA Director General Statement on Recent Developments in the DPRK’s Nuclear Programme, IAEA, December 2023,

[26] N Korea to launch new satellites, build drones as it warns war inevitable, Japan Today, December 2023, 

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