Russia Provides North Korea with Nuclear Submarine Technology, Reports Say
September 18, 2025 – Newsweek
Intelligence reports from South Korea indicate that Russia has supplied North Korea with critical nuclear submarine technology, including a nuclear reactor, to advance its submarine fleet capabilities. This development marks a significant step in the growing strategic military partnership between Moscow and Pyongyang.
Details of the Transfer
According to multiple South Korean government officials cited by the Korea JoongAng Daily, Russia delivered "two to three nuclear submarine modules" to North Korea in the first half of 2025. These components encompass a nuclear reactor, turbine, and cooling system—key elements for powering a nuclear submarine. Notably, these modules were reportedly sourced from decommissioned Russian nuclear submarines rather than being newly manufactured parts.
One official revealed that while Russia had initially resisted North Korea’s requests—made since last year—for nuclear propulsion technology and advanced fighter jets, it eventually agreed to provide the submarine-related technology. South Korea has shared this intelligence with its allies, including the United States, as it continues to verify the information’s credibility. The South Korean Defense Intelligence Agency stated it is closely monitoring the situation.
Efforts to secure comments from Russia’s defense and foreign ministries have so far been unsuccessful, and North Korea’s embassy in Beijing did not immediately respond to inquiries.
Strategic Partnership Context
This exchange underscores the expanding military cooperation between Russia and North Korea, formalized last year through a strategic partnership agreement. North Korea has provided troops and munitions to support Russia’s war effort in Ukraine in return for military equipment and technological support from Moscow.
North Korea has been actively enhancing its naval power, focusing on the construction of a nuclear-powered guided-missile submarine alongside two 5,000-ton destroyers. This expansion aims to counterbalance the superior naval forces of the United States and South Korea in the region.
Significance of Nuclear-Powered Submarines
Unlike conventional diesel-electric submarines, nuclear-powered submarines offer virtually unlimited endurance, speed, and operational range, limited only by onboard food supplies. Only a handful of countries, including the United States and Russia, currently operate such vessels.
In March 2025, North Korean state media disclosed that a "nuclear-powered strategic guided missile submarine" was under construction. North Korean leader Kim Jong Un personally toured the submarine and emphasized the importance of developing nuclear-armed naval forces as a vital part of the nation’s defense strategy.
The United States currently maintains a similar class of submarines, including four Ohio-class boats that have been converted from nuclear missile launchers to conventional strike platforms armed with up to 154 Tomahawk cruise missiles, each capable of striking targets up to 1,000 miles away.
Leadership Statements
During a high-profile meeting in Beijing on September 3, 2025, Russian President Vladimir Putin praised the growing alliance with North Korea, highlighting the "special dimension of trust, friendship and alliance" between the two nations. He also acknowledged and honored North Korean soldiers’ contributions, likely referencing their involvement in the conflict in Ukraine.
Earlier in March, Kim Jong Un declared that North Korea would not remain passive amid perceived threats from "naval and underwater military maneuverings" by adversaries. He emphasized the nation’s resolve to defend its maritime sovereignty and to strengthen its naval forces as part of securing the Korean peninsula and regional security.
Regional and Global Implications
The timeline for North Korea’s launch and commissioning of its first nuclear-powered submarine remains unclear. However, its eventual deployment may spur South Korea to accelerate plans for its own nuclear-powered submarine capabilities in response.
This technological transfer could significantly alter the naval balance in Northeast Asia, escalating tensions and prompting increased military vigilance among regional actors and their allies.
For further updates on this developing story, stay tuned to Newsweek.
Reporter: Ryan Chan
Based in Hong Kong, Ryan Chan specializes in security and defense issues in the Western Pacific. He has over a decade of experience reporting on China and broader geopolitical developments. Contact: r.chan@newsweek.com
