North Korea recently revealed it was building a nuclear-powered submarine for the first time. However, military experts believe Pyongyang faces overwhelming technical challenges that make its nuclear submarine ambitions nearly impossible — even with Moscow’s help.
North Korea’s official Rodong Sinmun on Saturday released images of a “nuclear-powered strategic guided missile submarine” under construction, along with a report of leader Kim Jong-un‘s visit to a major shipyard.
![Leader Kim Jong-un visits a major shipyard in this photo carried by North Korea's official Korean Central News Agency on March 8, [YONHAP]](https://www.koreadailyus.com/wp-content/uploads/2025/03/0313-submarine.jpg)
The project is part of a defense strategy announced at its ruling Workers’ Party Congress in 2021, marking the regime’s first public disclosure of what is believed to be a ballistic missile submarine (SSBN) under development.
Despite the display, experts remain highly skeptical of North Korea’s ability to produce a functional nuclear-powered submarine, pointing to major technological, industrial and material limitations.
“North Korea does not have the capacity to produce a nuclear submarine,” said Sam Tangredi, the director of the Institute for Future Warfare Studies, in an interview with Voice of America (VOA) on Wednesday. “That requires a substantial supply chain and infrastructure to acquire the materials and knowledge of nuclear propulsion.”
Tangredi emphasized that even countries with established nuclear power plants struggle to design submarine reactors, saying even China “took a considerable length of time” to develop this capability.
Some experts noted that the nuclear reactor is the heart of a nuclear-powered submarine, while North Korea is far from capable of developing one on its own.
“The key question for North Korea in this case is that a submarine’s nuclear reactor is a very advanced technology,” said Bruce Bennett, a senior researcher at the RAND Corporation, to VOA. “I don’t think they’re going to be able to put together a submarine’s nuclear reactor without substantial Russian help.”
Bennett pointed to the United States’ Columbia-class SSBN as an example, noting that even with America’s extensive nuclear submarine experience, the Columbia-class will take “eight to nine years” to build. Given North Korea’s lack of experience, experts doubt Pyongyang can develop and assemble a functional nuclear propulsion system anytime soon.
Other critical technologies are needed to create an operational nuclear submarine, including noise reduction technology to evade enemy detection, submarine-launched ballistic missile (SLBM) capabilities and advanced sonar and navigation systems. Bennett pointed out that “a lot of those tasks North Korea hasn’t even experimented with.”
![Leader Kim Jong-un visits a major shipyard to inspect the progress of building a nuclear-powered submarine in this photo carried by North Korea's official Korean Central News Agency on March 8. [YONHAP]](https://www.koreadailyus.com/wp-content/uploads/2025/03/0313-submarine-2.jpg)
Yoshihiro Makino, a visiting professor at Hiroshima University and diplomatic correspondent for Japanese daily Asahi Shimbun, highlighted another major challenge — the need for specialized materials that can withstand extreme underwater pressure.
“A submarine must have a hull capable of withstanding extreme underwater pressure,” said Makino in an interview with Radio Free Asia on Wednesday. “It’s difficult to understand how North Korea could have suddenly acquired such advanced technology.”
Beyond legal and diplomatic concerns, Yoshihiro warned that North Korea’s growing military capabilities could eventually pose a threat to Russia itself.
“Russia has never exported offensive weapons abroad that it couldn’t defend against,” he said, suggesting that if North Korea and Russia’s relations deteriorate, there is no absolute guarantee that Pyongyang would not one day threaten Russia with its nuclear arsenal.
South Korea’s Unification Ministry spokesperson Koo Byoung-sam said in a regular press briefing Monday that Seoul has been “closely monitoring” any signs of Russian involvement in Pyongyang’s military development and emphasized that any provision of military technology to North Korea is “strictly prohibited under UN sanctions.”
BY SEO JI-EUN [seo.jieun1@joongang.co.kr]
