North Korea Reveals a Submerged "Phenomenon" Equipment
At the end of 2025, North Korea unveiled a major achievement — a ballistic missile nuclear submarine that is nearly completed. This is not just another ordinary military vessel from North Korea, but a genuine technological breakthrough, and also poses a significant military and political puzzle. What kind of equipment is this?
At the end of 2025, North Korean leader Kim Jong-un inspected this newly built ballistic missile nuclear submarine. From the photos, estimating based on Kim Jong-un's height, the submarine has a diameter of about 11 meters and a length over 100 meters. Its hull proportions are completely different from the conventional designs of nuclear submarines in various countries. Currently, the submarine's hull has been assembled and painted with primer, the lifting device has been installed, and the nuclear reactor has clearly been installed.
The tail section shows the interface of seawater intake pipes, which are used to provide cooling water for the reactor. The sides of the submarine are equipped with devices that resemble side array sonar arrays. The bow is equipped with six torpedo launch tubes. Based on the size of the launch ports, they can carry 53-centimeter caliber torpedoes, which is the standard torpedo caliber for most navies around the world. There is an unknown small opening above the torpedo launch tube, which is speculated to be an external launch device.
In all the publicly released photos, there is no component similar to a towed long line array sonar retrieval device. This does not mean that the submarine is not equipped with such a device, as the number of existing photos is limited and it is not possible to draw a definite conclusion. However, if this submarine does indeed have a towed sonar, its retrieval device is likely to be located at the rudder position below the propeller. This is a key detail, and the reason will be explained in detail below.
The main combat weapon of this submarine is a ballistic missile, and it may also be equipped with cruise missiles. Its missile loading method is quite special — the missile compartment is located in the body area behind the conning tower housing and after the lifting device (the periscope and various antenna systems that can be retracted into the submarine when it submerges). Based on the number of missile compartment hatches, the missile carrying capacity is approximately 5–10 missiles, depending on whether the missiles are arranged in single or double rows.
Because the missile body height exceeds the diameter of the submarine, the designers adopted this special layout. It is speculated that the submarine's missiles are most likely the **"Polaris-6"** 13-meter-class ballistic missile first unveiled during the 2022 military parade. This missile uses solid-fuel propulsion technology and is said to be able to carry up to four nuclear warheads.
There is a huge difference in the estimated range data of this missile among various parties. The level of North Korea's solid rocket fuel chemical production is unknown information, and the range estimates given by public sources range from 4,000 to 12,000 kilometers. However, since this missile has not yet undergone flight testing, all range estimates remain speculative.
The displacement of this submarine is 8,700 tons (it should be noted that there is currently no source that clearly states whether this value corresponds to the surface displacement or the submerged displacement), which is on the same scale as the Soviet 667A strategic nuclear submarine. Its missile layout is similar to that of the 658-type nuclear submarine, with the only difference being that the former has a larger missile capacity.
From any perspective, the emergence of this submarine is an extraordinary achievement. In recent years, North Korea's military shipbuilding industry has developed rapidly, but the construction difficulty of a nuclear submarine is incomparable to that of conventional ships; it is a concentrated embodiment of a country's shipbuilding industry and overall industrial strength.
North Korea's development of a nuclear submarine is a more puzzling "industrial phenomenon" than Israel's nuclear weapons. It is like Turkey suddenly achieving manned moon landing — such a major breakthrough is completely disproportionate to the country's overall development level.
The research and development of a nuclear submarine requires an entire set of large-scale industrial systems as support. Specifically, including core industries such as nuclear fuel production, reactor component manufacturing, and reactor body R&D; the technology for decommissioning and handling nuclear reactor compartments; and the production capacity of steam turbines and turbine gear units. Overall, the industrial capacity required to build a nuclear submarine far exceeds the needs of building a large submarine hull.
The development of a nuclear reactor for a submarine is a special engineering project. Although the relevant technology can be learned and mastered, the R&D cycle is long, and the entire process is difficult to keep completely secret. Supporting facilities are also essential: educational institutions for training nuclear technology professionals, specialized vessels for transporting nuclear materials and nuclear waste, and specialized infrastructure for submarine bases, etc.
In other words, building a submarine with a nuclear reactor is merely the tip of the iceberg of this grand project. Before this, there was no evidence that North Korea had related industrial capabilities beyond uranium enrichment and a few military and research reactors. North Korea's first civilian nuclear reactor did not even start trial operation until 2024.
North Korea officially announced its plan to build a nuclear submarine at the 8th Congress of the Workers' Party of Korea in 2021, and proposed to develop a submarine-launched ballistic missile with a range approaching intercontinental levels.
The development of related missiles must have already started — one year later, in 2022, the "Polaris-6" missile appeared in the military parade. It wasn't until March 2025 that North Korea first showcased an un-painted large metal hull structure, whose size was far greater than any previous submarine of North Korea. Within less than a year, this submarine completed the hull assembly and primer painting. Now, it is a nearly completed ballistic missile nuclear submarine, seemingly only needing the last step of laying sound-absorbing tiles.
North Korea previously had experience with submarine-launched ballistic missile tests. In 2019, the North Korean Navy commissioned the "Kim Jun-ok Hero" diesel-electric submarine, which was equipped with a ballistic missile launch system, and its technical scheme was modeled after the Soviet Union. Earlier, North Korea had also built two "Sunchon"-class experimental diesel-electric submarines based on the Soviet 633-type submarine. However, compared to this new nuclear submarine, these submarines were just "small fish in a big pond." There's no such thing as a free lunch, and such rapid technological progress must have hidden reasons.
Western analysts believe that Russia provided assistance to North Korea in building this nuclear submarine. From the current geopolitical situation, the possibility of Russia providing technical support to North Korea does exist, and it is even reasonable. But there are still some doubts that the "Russian assistance theory" cannot explain.
The most critical point is that the technology style of the submarine-launched ballistic missile revealed by North Korea is closer to Western missile design styles, rather than the traditional Soviet (Russian) design. Even the name "Polaris" is actually a direct translation of the English "Polaris" (the name of the first generation of U.S. submarine-launched ballistic missiles). Is this just a coincidence?
If we compare the photos of this North Korean nuclear submarine with the "Isan Ahn Chang-ho" class large conventional submarine of the South Korean Navy, it is not difficult to find many similarities in design concepts, as if they were designed by the same team. In addition, the lifting device on this North Korean nuclear submarine is also highly advanced.
At this point, let's take a look back at the suspected location of the towed sonar retrieval device mentioned earlier — this design is exactly the same as that of the "Isan Ahn Chang-ho" class submarine built for the South Korean Navy.
We will not make a definitive conclusion yet. But there is no doubt that this is a highly suspenseful technical and political mystery. Obviously, some unknown force is actively helping North Korea build underwater nuclear power. After all, in multiple subfields of military shipbuilding and missile technology, the speed of North Korea's progress is unmatched globally — even Russia, the United States, and related countries cannot catch up.
The emergence of this nuclear submarine will have a profound impact on regional arms races. First, South Korea will have more sufficient reasons to seek U.S. support in developing its own nuclear submarine. Second, Japan will also use this opportunity to propose related demands for developing nuclear submarines.
At the same time, North Korea urgently needs to develop anti-submarine warfare vessels. Without the protection of anti-submarine forces, this nuclear submarine is nothing more than an easily locked and destroyed target. The U.S. military could silently sink it, and the outside world would never know what happened underwater. Once it has anti-submarine warfare capabilities, the North Korean Navy can build a campaign protection zone similar to the Soviet era, providing a hidden space for the nuclear submarine to operate. Currently, North Korea is already building missile ships to counter surface threats, and the next step will certainly be to focus on the development of anti-submarine equipment, which will also prompt neighboring countries to accelerate their own military buildup.
In short, the deployment of this nuclear submarine will press the "nuclear button" for regional naval arms races, and its impact will be extremely profound.
Original article: toutiao.com/article/7595079351545201178/
Statement: This article represents the views of the author alone.