North Korea shows first domestically built nuclear submarine

Key Points
  • North Korea says it has formed the first corps of a domestically produced nuclear-powered strategic guided missile submarine, unveiled during Kim Jong Un’s visit to the Pongdae Shipyard.
  • Analysts warn the submarine, if completed as described, could carry nuclear-armed ballistic missiles and expand Pyongyang’s sea-based nuclear capability with potential implications for U.S. and regional security.

North Korea has unveiled what it describes as the first corps of a domestically produced nuclear-powered submarine.

The announcement was made by Korean Central News Agency, which reported that the submarine was presented during a visit by leader Kim Jong Un to the Pongdae Shipyard. The vessel is described as an 8,700-ton nuclear-powered strategic guided missile submarine that is currently under construction.

KCNA said Kim used the visit to criticize recent developments involving South Korea and the United States. “Saying that the nuclear submarine development plan of the ROK, which Washington has agreed on at the solicitation of Seoul recently, will worsen the instability in the region of the Korean Peninsula, he stressed that the DPRK regards it as an offensive act severely violating its security and maritime sovereignty and a threat to its security that must be countered,” KCNA reported, using acronyms for South Korea and North Korea.

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The North Korean leader made the remarks during what the agency described as an on-site inspection of the submarine hull and internal structures. KCNA reported that Kim also said the nuclear armament of the navy had become an urgent task in light of what he called a worsening security environment around the Korean Peninsula.

Observers quoted by South Korean media say Pyongyang is seeking to justify its own nuclear weapons development by pointing to Seoul’s plans for nuclear-powered submarines. South Korea has publicly discussed building submarines that would use nuclear reactors for propulsion but carry only conventional weapons, a distinction Seoul has emphasized in statements to allies.

8,700-ton nuclear-powered strategic guided missile submarine at Pongdae Shipyard. (Pyongyang's state-run Korean Central News Agency)
8,700-ton nuclear-powered strategic guided missile submarine at Pongdae Shipyard. (Pyongyang’s state-run Korean Central News Agency)

“North Korea’s nuclear submarine construction, which was officially announced at the 2021 Eighth Party Congress, appears to have made considerable progress,” said Lim Eul-chul, an expert on North Korea at the Kyungnam University Institute for Far Eastern Studies. “The North’s submarines are no longer a hypothetical threat but an emerging reality that could threaten not only South Korea but also the U.S. mainland,” Lim added.

Photos released by KCNA show what analysts assess to be a nearly completed pressure hull, with external features consistent with a ballistic missile submarine. Analysts say that if the vessel is indeed an 8,700-ton-class submarine, it would likely rely on highly enriched uranium, with enrichment levels exceeding 90 percent. In such a configuration, the reactor would not require refueling during the submarine’s operational lifetime.

This approach would differ sharply from South Korea’s plans. Seoul is expected to complete its first nuclear-powered submarine around 2035, with U.S. backing for nuclear fuel supplies. South Korean designs are expected to use low-enriched uranium at roughly 20 percent, which would require reactor refueling at intervals of about 10 years. South Korean officials have repeatedly stated that their program is focused on endurance and stealth rather than nuclear armament.

North Korea, by contrast, is believed to be pursuing a platform capable of carrying ballistic missiles armed with nuclear warheads, expanding its sea-based nuclear deterrent beyond diesel-electric submarines.

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