North Korea’s Nuclear Sub Under Construction Is Massive, Points to Russian Assistance

North Korea recently showed the first images of its nuclear powered submarine. The boat, which had been rumoured for some time, is now looking more credible. It’s immense size points towards long-range nuclear armed missiles. Will this accelerate South Korea’s move in a similar direction?

As a more countries pursue nuclear weapons to create independent deterrents, North Korea is pushing ahead with an increasingly ambitious program. Its construction of a nuclear powered, and nuclear armed, submarine is likely to escalate an arms race on the Korean peninsula.

While the North Korean submarine may be years away from an operational capability, it is already reshaping the nuclear debate. The discussion on South Korea acquiring both nuclear weapons, and its own nuclear powered submarines, has gained new energy – both in public discourse and likely behind closed government doors.

North Korean Nuclear Submarine

In 2019 there was talk of nuclear disarmament when the leader of North Korea, Kim Jung Un, met President Trump. Beyond the grandiose photo opportunities, these went nowhere and today North Korea has more nuclear weapons than ever. And North Korea already has credible ways of delivering them. These include rudimentary missile submarines and underwater drones. The new nuclear submarine will add further credibility.

When it was launched in September 2016 the single Gorae-class boat was the smallest ballistic missile submarine in the world. Essentially a scaled-up Yono-class midget submarine, it featured only a single missile silo in the sail. Yet it was evidently up to the task of testing North Korea’s ballistic missiles, and pushing the boundaries of North Korean submarine construction at the same time. Missile submarine development has focused on converting a much older type, the Soviet-era Project 633 Romeo-class. This, until now the largest submarine in North Korea, has been adapted to carry cruise missiles and shorter range ballistic missiles.

North Korean missile technology has been developing fast. Learning from many tests, some successful and some less so, it is now mature. Russia is even using some shorter-range types in its invasion of Ukraine. In the submarine launched missile department the Pukguksong (north pole, aka Polaris) family has developed ever larger missiles.

The Submarine’s Great Girth

There have been  some missteps however. One Romeo-class boat being modified to carry larger ballistic missiles has never been seen in the water. Construction was likely shelved some time in the early 2020s. The most likely explanation is that North Korea found that newer submarine-launched ballistic missiles require a larger submarine. Now North Korea needs a submarine large enough to carry them.

Based on analysis of photos of the visit to the shipyard, the submarine is around 12 meters (40 ft) in diameter. This is broadly in line with the ballistic missile submarines of leading nations. This makes it, for a North Korean boat, unexpectedly large.

Possibly it uses double hull construction, whereby an inner pressure hull is surrounded by a second outer hull which is flooded. This would mean that the inside diameter of the boat is around 10 meters (33ft); still a very large submarine but more achievable. It is harder to gauge length, but it is easily over 100 meters (328 ft) long, with 130 meters (427 ft) a good starting figure.

Underway On Nuclear Power

The driver of the boat’s size is more likely to be the missiles than the nuclear power plant. The missiles are likely to be later versions of the Pukguksong family. The latest iteration, provisionally labelled Pukguksong-6, is approximately 13 meters (ft) long. This is comparable to the Trident missiles carried by American and British submarines. Although ranges haven’t been published, North Korean missile technology is maturing and it is possible that these missiles will be able to target American cities from the seas off Korea.

Such a large submarine could not realistically be conventionally powered however. The nuclear reactor, with its pumps, piping and pressure vessels is likely to take up a significant portion of the submarine. There is natural speculation that Russia has assisted in this technology, although North Korea may have been working on it for some years already.

Russian assistance, which is not improbable, may include other more elusive submarine technologies. These could logically include quietening and sonar. Overall however we can expect a comparatively basic design with limited stealth and poor sensors. Its main purpose will be to carry the missiles.

The nuclear debate in South Korea has been rekindled. Local media are discussing the country’s acquisition of nuclear weapons. And the nuclear submarine debate, with previous discussion of acquiring this technology, remains present. South Korea currently possesses superior submarine technology with the KSS-III armed with conventional missiles. But a North Korean nuclear boat will challenge this, even if it is less sophisticated. Combined with more U.S. allies looking to independent nuclear weapons, the die seems cast.

Source: Naval News