Capability for Kim Jong-un’s submarines to launch missiles from anywhere would be a game changer
22 September 2025
Reports of Russia transferring nuclear submarine reactor technology to North Korea have surfaced over the past week. This is believed to be payback as Pyongyang sends troops and munitions to support Russia’s war in Ukraine: over 12,000 soldiers have deployed since October 2024, with plans for 30,000 more, according to Ukrainian estimates. UK Ministry of Defence figures put North Korean casualties at up to 600 killed and 4,000 wounded. In exchange, Kim Jong-un gets salvaged reactors from decommissioned Russian submarines, reportedly to be delivered this year. It’s a straightforward quid pro quo: cannon fodder for Moscow, nuclear powered submarines for North Korea.
North Korea has been pushing for advanced military technology since the June 2024 mutual defence pact with Russia. Requests included nuclear submarine tech and Su-35 fighter jets – those latter not quite Russia’s very latest, but probably the most advanced jet that Putin can spare in any numbers. The reactors being considered are compact pressurised water types and experts believe they’re sufficient to power a 7,000-ton submarine – big enough to carry vertical launch tubes. In other words, an attack submarine (SSN) with cruise missile capability or, more worryingly, a boat able to launch ballistic missiles (SSBN). Both cruise and ballistic weapons can have nuclear warheads, but ballistics are much harder to defend against.
Xi Jinping seems unfazed at the prospect of a much more militarily powerful North Korea: China shipped 19,000 tons of sugar to Pyongyang last week ahead of the Workers’ Party’s 80th anniversary, suggesting business as usual. For Russia, the transfer is a calculated risk: short-term battlefield help vs the possibility of sanctions blowback for violating the Non-Proliferation Treaty (NPT).
North Korea’s fleet nominally includes 70-plus submarines, mostly diesel-electric relics like the Soviet designed Romeo-class (20 hulls) and the Sang-O and Yono midgets (40+). These are fine for coastal operations, but lack the endurance or stealth for open ocean work.
In late 2023 an unholy bodge, a Romeo class with a missile section bolted on, was unveiled and met with a mix of derision and pity for anyone told to sail in it. As a threat, it was not taken seriously. Diesel-electric submarines cannot travel far or fast when submerged, and can’t stay down for all that long even moving at a crawl.
A new player on the world board
Nuclear propulsion changes everything, however. It means unlimited submerged runtime, 20+ knot submerged speed and worldwide range. The endurance of a nuclear powered sub is limited only by food for the crew – it makes its own air and water. A sub which can stay down for months on end is very difficult to detect or locate. This is why people put nuclear ballistic missiles on nuclear submarines: the enemy cannot locate your missiles and thus cannot knock them out with a pre-emptive strike.
Execution will be the problem. North Korea’s yards are sanction-hit and expertise thin, as the occasional massive blunder shows. Even with Russian help, producing a fully operational nuclear powered boat will take years. But if they manage it, a new player on the world board with unstrikeable ballistic nukes will definitely change the game.
Like many things Vladimir Putin does, the transfer is illegal under international law: Russia, as a nuclear weapon state under the NPT, can’t transfer such tech. North Korea quit the NPT in 2003, but UN Security Council resolutions (1718-2397) ban such aid outright nonetheless as violating the UN Charter’s Article 25. It’s a direct breach; now we have to see who cares.
Reaction has been muted so far. South Korea calls it escalation; Ukraine welcomes increased scrutiny on Russia’s enablers. No Western leaders have been quoted yet, but we can expect IAEA noise and tighter sanctions talks in due course. China stays silent, for now. For the UK, current defence pacts with allies in the region such as the AUKUS attack submarine alliance and the GCAP fighter jet project – which includes Japan – cause us to take notice, particularly as the risk to Taiwan just went up. As ever, our options to respond are limited.
The solution is investment: in verification, allies and deterrence. For the West, it’s a reminder to enforce red lines: NPT snapbacks, asset freezes, even counter strikes before rogue tech swaps, cyber-attacks and airspace violations escalate into outright invasions… again.
All submarines are formidable when well operated and ones with nuclear propulsion are a huge step up in lethality. Put nuclear missiles in them and they become a strategic gamechanger. These ones might be some time coming, they might not be very well run at first when they do appear and there is a plethora of political and military noise elsewhere drowning it all out, but it shouldn’t distract from what’s happened here. Russia has just put another totalitarian regime on the road to an undetectable nuclear strike capability.
Comment from :
Shaun Nelson
Time to eradicate these two madmen.
This is not a James Bond movie.
Free their people by topping them both!👍😡
The chicoms have used the norks as their junkyard dogs for 70 years.
But now the balence of power has changed. In the 1950’s, Stalin and his successor Khrushchev were the senior partners of the Sino-Rus relationship and they weren’t particularly friendly with each other. Now jinping is the capo di tutti i capi and putler and Kim are both his junkyard dogs/enforcers.
We have allowed these fucking turds to build their axis of evil with no pushback whatsoever.
Sensible leaders, which we haven’t had since Reagan-Thatcher, would have pushed back on these filth long before now.
We really have got to smash the chicom economy, as well as that of the putinaZis.
The Axis of Evil is just taking the piss at the moment.
Re. Commenter Nelson : “topping” is cockney gangster slang for killing. I guess he used it because the mods would have blocked the word “killing” in that context.
Nigel Farage, who is on course to be the next U.K. PM has been promoting his policy that will save £234 billion/year by kicking out benefits sponging immigrants.
That sounds like a winner to me.
But unfortunately Farage is another OrbanaZi and will make Britain into another Orbanistan; but with a much more powerful economy.
It is the failure of the Tories and Labour to deal effectively with the horde of invaders from primitive cultures that has put this putlerist on the brink of power.