IRIA News

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North Korea has revealed an 8,700-ton-class nuclear-powered strategic ballistic missile submarine, marking a significant development in its efforts to expand nuclear strike capabilities beyond land-based systems.

North Korean state media released photographs showing leader Kim Jong-un inspecting the construction of the vessel, which Pyongyang says will play a central role in its nuclear war deterrence.

The announcement, made on December 25, 2025, did not disclose the exact time or location of Kim’s visit. However, the release of detailed images of the submarine’s exterior and hull suggests the project has advanced to a late construction stage.

Analysts say the disclosure is intended to send a strategic message to the United States and South Korea at a time of heightened regional tension and deepening alignment between Pyongyang and Moscow.

Kim Jong-un Inspects Construction Site

According to state media, Kim Jong-un visited a shipyard where he inspected what North Korea called a “nuclear strategic attack submarine.” He was accompanied by senior officials and his daughter.

During the visit, Kim reaffirmed his commitment to strengthening the country’s naval nuclear forces, stating, “We have steadfastly built a nuclear shield that can reliably protect the nation’s safety.”

Kim described the submarine project as a “historic turning point” and an “epoch-making” development that would significantly enhance North Korea’s nuclear deterrent.

He emphasized that Pyongyang’s position on denuclearization remains unchanged, reiterating what officials refer to as the “non-denuclearization impossible theory.”

“Our party and government’s resolve to ensure absolute safety through nuclear forces remains unwavering,” Kim said, adding that North Korea would “continue strongly advancing the nuclear armament of the navy.”

Capabilities and Features

North Korea claims the submarine is capable of launching nuclear-armed submarine-launched ballistic missiles, indicating it is designed as a true nuclear-powered ballistic missile submarine, or SSBN. Images and assessments suggest the vessel includes 10 vertical launch tubes for SLBMs, potentially allowing it to carry up to 10 nuclear missiles.

In addition to the missile tubes, six torpedo launch tubes were identified at the front of the submarine. State media said Kim was briefed on the “research status of newly developed underwater secret weapons,” with images suggesting the development of advanced torpedoes and underwater mines.

Experts note that submarines are typically built from the inside out, meaning that the appearance of a largely completed hull suggests many internal systems, including propulsion components and possibly a reactor, are already installed. The welding of large hull sections is seen as an indication that reactor compartments may already be in place.

If confirmed, the installation of a nuclear reactor would allow the submarine to operate underwater for extended periods. In theory, the use of highly enriched uranium as fuel could enable near-indefinite submerged operations, greatly increasing survivability and stealth.

Second-Strike Implications

The operationalization of a nuclear-powered ballistic missile submarine would represent a major shift in North Korea’s nuclear posture. Such a platform would provide a second-strike capability, allowing Pyongyang to retaliate with nuclear weapons even if its land-based missiles and facilities were destroyed in an initial attack.

Submarine-launched missiles are significantly harder to detect in advance, raising concerns among neighboring countries. A stealthy platform capable of operating far from North Korea’s coastline would complicate missile defense planning and early warning systems across the region.

South Korea’s government and military have not issued an official response confirming or denying North Korea’s claims regarding the submarine’s capabilities.

Message to the United States and South Korea

North Korea’s decision to unveil the submarine on Christmas Day was widely interpreted as a symbolic message to Washington, which continues to call for the “complete denuclearization of North Korea.” Kim used the occasion to criticize South Korea’s own ambitions to acquire nuclear-powered submarines, a move Seoul has discussed with Washington.

Kim described South Korea’s plans as an “aggressive act that seriously infringes on national safety and maritime sovereignty,” and said they justified North Korea’s drive to modernize and nuclear-armed its military forces.

South Korea’s proposed submarine would be a nuclear-powered attack submarine, or SSN, using nuclear propulsion but not carrying nuclear weapons. By contrast, North Korea’s vessel is explicitly described as a strategic platform intended to carry nuclear-armed missiles.

Sanctions and Russia’s Possible Role

Questions persist over how North Korea, which remains under extensive United Nations Security Council sanctions, could obtain the resources and technology needed to build a nuclear-powered submarine. The transfer of nuclear reactors or related technology would constitute a serious violation of international sanctions.

Some analysts have raised the possibility that North Korea’s growing alignment with Russia may have played a role. Pyongyang has sent thousands of troops and large quantities of military equipment to support Russia’s war in Ukraine, leading to speculation that advanced technologies could be flowing back in return.

While some experts suggest North Korea may have sought a reactor from Russia, possibly from a retired submarine, others believe Pyongyang may have designed its own small-scale reactor, potentially with technical assistance. No independent confirmation has been made.

Part of Broader Weapons Program

A nuclear-powered submarine was included in a list of advanced weapons Kim Jong-un outlined during a political conference in 2021. That list also featured solid-fueled intercontinental ballistic missiles, hypersonic weapons, military spy satellites, and multi-warhead missile systems.

North Korea has since tested or unveiled several of these systems. It recently revealed a new naval destroyer, which Kim said would expand the operational range and preemptive strike capabilities of the country’s nuclear forces.

State media also reported that Kim supervised tests of new anti-air missiles fired into the sea. South Korea’s military said it detected several missile launches from an eastern coastal town, underscoring the continued pace of North Korea’s weapons testing.

Rising Regional Tensions

Tensions on the Korean Peninsula have intensified in recent years as Kim accelerated nuclear development and deepened ties with Moscow following Russia’s full-scale invasion of Ukraine in 2022. Pyongyang has rejected renewed calls from Washington and Seoul to resume negotiations aimed at rolling back its nuclear and missile programs.

Previous talks collapsed in 2019 after a failed summit between Kim and then-President Donald Trump. Since then, North Korea has increasingly framed its nuclear arsenal as non-negotiable.

The unveiling of a nuclear-powered ballistic missile submarine underscores that stance, signaling Pyongyang’s intent to move toward a more survivable and sophisticated nuclear force. For regional actors, the development raises fresh concerns about stability, deterrence, and the growing complexity of security dynamics in Northeast Asia.