SSN/SSBN - Nuclear Powered Submarine

Kim Jong-un vowed 09 January 2021 to expand North Korea's nuclear arsenal unless the United States "withdraws its hostile policy". The North Korean leader said he will develop more sophisticated atomic weapons systems to combat "hostile forces" that threaten the DPRK. Kim ordered officials to develop weapons with multiple warheads, spy satellites, underwater-launched nuclear missiles and nuclear-powered submarines. Today there are only a few states in the world whose shipbuilding industry has sufficient scientific and technical potential for the design and construction of modern nuclear submarines.

North Korea’s lack the capability to construct a nuclear-submarine, Cha Du-hyeogn, South Korea’s former presidential secretary for crisis information who is now a research fellow at the Asan Institute for Policy Studies said 08 September 2023. “While North Korea is interested in acquiring it, building one in the short term presents significant technical challenges. Military collaboration with Russia may occur in part to address this gap. But it would be difficult to imagine Moscow supplying Pyongyang with nuclear submarines or transferring relevant technologies. Even with the transferred technology, constructing a nuclear submarine within a short time frame remains a challenge to North Korea.”

There are reports that when President Vladimir Putin and Kim Jong Un meet in Vladivostok there will be a request for Russian nuclear propulsion technology in exchange for the large amounts of ammunition and arms Putin needs desperately for his continuing war in Ukraine.

From the Russian perspective, there is talk of receiving conventional ammunition or missiles from North Korea to help in the war in Ukraine. Russia's stock of conventional weapons is in great trouble. It is difficult for Russia to provide food to North Korea because of the war in Ukraine. Then, it is difficult to provide cash because of sanctions against North Korea, and sanctions on Russia. So Russiia could give them advanced technology. If military cooperation between China, North Korea, and Russia and North Korea, China, and Russia really materialize, cooperation between Korea and the United States and Korea, the United States, and Japan will inevitably be strengthened.

In October 2017, the ROK Navy commissioned the Seoul-based Korea Defense Network to conduct a five month study on the feasibility of developing an indigenous nuclear-powered attack submarine. The think tank reported in March 2018 the results to the Navy, suggesting the service build a nuclear attack submarine along the lines of the French 5,300-ton Barracuda-class sub, which has a length of 99.5 meters. The French Rubis class nuclear-powered attack submarines, with a displacement of 2670 tons submerged and a length of 72 meters (236 ft), is the smallest SSN type in operational service with any navy.

A North Korean nuclear-powered attack submarine does not solve any evident North Korean problems. It would certainly be a noisy contraption compared to American nuclear-propelled attack submarines, and noisy compared to South Korean and Japanese diesel-electric boats. The advantages of nuclear propulsion, notably long endurance submergence, are of little value in North Korean home waters.

In recent years the DPRK has been working on a modification of the ROMEO diesel-election submarine capable of launching three medium-range NK-11 ballistic missiles from tubes in the submarine's sail. Such a configuration was used by the Soviet GOLF class conventional submarines and the HOTEL class nuclear submarines. The Korean missile's range could cover regional targets such as South Korea, Japan and Guam, but the Mod-ROMEO could not effectively bring these missiles within range of the Continental United States. An ICBM-class submarine launched missile, capable of reaching North America if fired from a bastion of North Korean home waters, is plausible but no moves in this direction are in evidence. A nuclear powered submarine could bring America within range of prospective North Korean missiles, even if the submarine could be tracked by American ASW assets such as SOSUS passive surveillance sensors.

In mid-2019 North Korea released a number of images of Kim Jong-un inspecting a new submarine. The images show the North Korean leader inspecting submarine under construction in drydock. Presumably the new sub is conventionally powered and will carry nuclear-tipped missiles that could threaten targets throughout the Asia-Pacific region. In the mid-1990s, North Korea acquired a small number of Project 629A Golf II ballistic missile submarines, with a length of about 99 meters and displacement of 3,550 tons Submerged. The Golf II class was based on the same Romeo-class submarines used by North Korea but modified to carry three missile tubes in the submarine’s sail. H.I. Sutton, author of the Covert Shores submarine blog, told Popular Mechanics the missile submarine is likely a conversion of one of North Korea’s Romeo-class submarines.

The Soviet Union's first nuclear powered submarine was the Project 627 Kit November class, with a length of 107 meters and a displacement of 4,700 tons. In the Soviet Union, the nuclear powered Project 658 HOTEL boats - based on the NOVEMBER design - carried 3 missiles, were 114 meters long and displaced about 5,000 tons.

In 1954, the US Navy launched the first submarine that used radioactive material as a power source. Its name was the USS Nautilus and it was the first submarine to travel to the North Pole in 1958. Before then, submarines used diesel engines and had to go into port for fuel. Nuclear power allowed submarines to run for about twenty years without needing to refuel. Food supplies became the only limit on a nuclear submarine’s time at sea.

Highly enriched uranium (HEU) containing 20 percent or more uranium-235 poses concerns about the possibility of nuclear proliferation which is not present with non-weapons-usable low-enriched uranium (LEU) fuel. Sébastien Philippe and Frank von Hippel noted that "The example of HEU use established by the U.S. Navy and the three other navies that use HEU fuel (India, Russia, and the United Kingdom) could be used by any non-nuclear-weapon state-party to the NPT, however, to legitimize acquisition of HEU – mostly likely through indigenous domestic production – and thereby a nuclear weapons option.... LEU fuel is already used in Chinese and French naval reactors. Little is known about China’s technology, but France has been relatively open... "

The atomic submarine ambitions of near-nuclear states such as Brazil and Iran are widely regarded as a pretext for circumvention of the Non-Proliferation Treaty. A North Korean atomic submarine project would provide a pretext for continued Uranium enrichment, and enrichment to near bomb-grade levels, even if North Korea were to forswear further enrichment for weapons purposes.

Many challenges must be overcome to design and build a general purpose submarine with useful characteristics and capabilities. Small size must be reconciled with high speed, navigation, seakeeping ability and long range. It has historically proven difficult to design a relatively small submarine capable of long-range navigating and seakeeping at high speed. Typical submarines that do the listed capabilities are extremely large, bulky, and expensive. Long-range underwater navigation has only been successfully accomplished through the use of nuclear power or enormous battery banks charged on the surface by diesel power. These methods are practical in large, transoceanic military submarines, but are not possible in a smaller submarine.

There are many different types of vessels that can be classified as submarines or submersibles. A submarine is typically considered an autonomous vessel, capable of moving forward and changing directions under water, capable of navigation on the high seas, with seakeeping capabilities, and capable of safely operating under water. A submersible is generally considered any vessel that can submerge and operate underwater, but may have limited or no capacity to navigate the seas on its own. Submarines and submersibles both carry human passengers under the surface of the water.

A general purpose submarine should be a capable navigator with a long operating range and strong seakeeping abilities. It should also be autonomous, capable of generating its own power and air supply and storing them for a dive. Such a vessel would be more efficient and less expensive than a vessel that requires a surface support vessel. The safety factor in rough seas would also be higher since it could ride out the storm without the assistance of a surface support vessel. The ability to navigate over a long range would allow private industry to be able dispense with the cost of a surface support vessel for the first time. The submarine could deploy from a regular dock and travel to its destination on its own.

Existing submersible designs incorporating pressure hulls are subject to catastrophic threats if swamping and leakage occur, and thus they require costly, complex safety engineering. Thus, using existing designs, it is not possible to achieve deep and long duration dives while also keeping the cost low and the design relatively simple. The next challenge in designing and building a general purpose submarine is reconciling design simplicity and low cost with safety. One of the key problems in designing a simple, low cost submarine has historically been the huge expense that goes into engineering safety into a typical submersible.

A good general purpose submarine should be able to attain decent speed, as traveling at high speeds is useful in many circumstances. Speed allows a tourist sub to carry more passengers without the need for a surface support vessel. Speed is also useful in military and security operations. Further, speed lowers mission duration, which decreases costs, and allows a vessel to avoid approaching storms.

A general purpose submarine should be configurable, possessing the ability to take on equipment needed for several different types of missions. Configurability is a key feature of a general purpose sub. Such a vessel should be able to increase passenger compartment comfort when used in a recreational or tourist role; have weaponry and armor added to it in a military role; and be equipped with cameras, manipulators, storage, and tools in a scientific or industrial role. These reconfigurations should not require substantial redesigning of the vessel; ideally these reconfigurations should not significantly increase the cost and time needed to deploy these variations of the general purpose submarine.

A general purpose submarine should be capable of diving and keeping passengers safe at depths that encompass the majority of water that is useful to industry and tourism. While for some purposes, such as tourism, depths of 33 feet may be sufficient, in many embodiments, such a vessel should be able to dive to at least 500 feet, covering about 90% of the useful water. These depths are sufficient to offer stealth to the military as it exceeds the depth at which light penetrates the water in most locations, and even long-range military submarines rarely operate below depths of 1,000 feet. For industrial operations, the majority of oil pipelines and infrastructure lie in the first 300 feet of water.

Some nations still use diesel-electric military submarines, which were in wide use during World War II. The modern versions display better submerged time, speed, stealth, and armament, but are similar in basic function. They use surface engines to charge electric batteries for a dive. Nuclear-powered designs that can spend months underwater have replaced many diesel-electric submarines in the U.S. Navy and in some foreign navies. The atomic reactors used to power these vessels can operate for years without needing to add fuel, and they typically only need to surface every few months to add supplies and exchange crews.

Transoceanic military submarines are used for many different missions, and each mission type is usually accomplished by a particular class of submarine. The U.S. Navy currently has the Ohio-Class Submersible Ship Ballistic missile Nuclear (SSBN), the Submersible Ship Guided missile Nuclear (SSGN)-Class, the Los Angeles and Seawolf Submersible Ship Nuclear (SSN) classes, and the Virginia SSN class. The Ohio-Class SSBN, also known as boomers, serve as a stealthy mobile launch platform for ballistic missiles. The SSGN-Class are boomers that are converted to carry cruise missiles and to serve as platforms for Special Forces operations. The L.A. and Seawolf SSN classes are fast attack submarines, and the Virginia SSN class is a fast attack sub, cruise missile launch platform, and Special Forces platform. All U.S. Navy submarines are atomic-powered and capable of diving to at least 800 feet below the surface of the water.

Transoceanic military submarines are designed for long-range cruising at relatively high speeds compared to surface vessels and for stealth. These vessels are typically as big as large surface ships. None of these military submarines have any non-military use. They are far too expensive and impractical to transport cargo. Passenger travel is cheaper, faster, more practical, and more comfortable by other means. Industrial use is not practical for these submarines since their size prevents operation around or under other vessels or offshore platforms. The lack of windows, large crew size needed for operation, and huge cost to produce precludes any tourism or recreational use. Thus, these huge military submarines have no other use besides their current warfare platform.

Any submarine or submersible must at least be able to attain negative or neutral buoyancy, and provide propulsion for the passengers. In submarines and submersibles, water is added to ballast compartments to help them sink below the surface. This can be looked at as either reducing the displacement of a vessel or increasing its weight; both have the same mathematical effect. In submarine terminology, adding ballast water is typically viewed as reducing the vessel's buoyancy. When ballast compartments are full, they are looked at as being essentially neutrally buoyant, and thus accounting for no buoyant force on the vessel. The mass of these ballast compartments must still be considered in the energy required to propel the vessel underwater. These ballast compartments are often called variable displacement, since they allow water to enter and reduce the buoyancy of a vessel by reducing its displacement.

For many years, national military strength and fighting capacity all making great efforts the advanced stealthy quiet atomic submarine of research construction, improve in each military power of the world. Build advanced stealthy quiet atomic submarine two big major techniques: reduce the noise of atomic submarine and the reflectivity of minimizing atomic submarine radar wave and sonar detection. In the United States Navy Seawolf nuclear naval vessels are with noise of nuclear naval vessels is about 100 decibels in Virginia. Submarine is one of the main equipment of naval in modern age, and it in use can run into various battle injury and marine accident. These accidents directly affect and threaten the survivability of submarine, and make submarine lose normal/cruise and perform the ability of combat mission, serious also causes submerged submarine in seabed.

Various countries all manage to reduce the noise that the nuclear naval vessels send desperately in building nuclear naval vessels process at present. The easiest propelling units such as screw propeller, pump and turbine that send noise of submarine are in the easiest generation cavitation of propelling unit of water body high speed rotation. Cavitation arises when local static pressure reduces, and causes the fracture of liquid or liquid one solid interface, break to form macroscopic view or visible bubble in bubble. Cavitation is the noise source of particular importance in the hydroacoustics. The submarine is in fact is not undetectable when cavitation is present.

The submarine propeller high-speed operation promotes current direction submarine rear flow at high speed, causes water body or water body one propelling unit generation cavitation, produce noise, and to around the borne noise ripple, the noise transmission of horizontal direction farthest, the ship in a distant place, warship and ship all are easy to detect.

The military science of each military power is developing the isolates sound technology at present, and breather vane propeller and waterjet propulsor reduce the noise of submarine in water body, improve the disguise and the military attack ability of submarine. Conventional submarine and atomic submarine are radiated the noise in water, are a kind of noises that the disguise of submarine itself is constituted a serious threat. Therefore, reducing submarine noise is the gordian technique of improving its combat capabilities.

The noise of conventional submarine and atomic submarine has three sources, and the one, by the running of the various mechanical equipments of Method for Inside Submarine's, vibration, friction, the major cycle water pump of the reducing gearbox of main frame and reactor etc.But the vibration of its various device and the noise of running are to pass to hull by the pedestal of equipment and air and other members, thereby cause the vibration of hull shell, and are radiated in water.The 2nd, screw propeller when rotation vibration, bounce current and the noise that produces; The 3rd, in the time of submarine movement, hull impacts the turbulent flow that causes of current and the hydrodynamic noise that produces.

At present, the measure of main noise-decreasing has: boat equipment adopt damping support or damping buoyant raft, adopts low noise screw propeller, development is used pump injecting type propelling unit that noise is less and the natural-circulation capacity (object is to cancel the noise of major cycle water pump) of MHD propulsion system, raising nuclear power plant, use electric propulsion (in order to eliminate the main noise sources of reducing gear in steam propulsion mode) etc., but its effect is undesirable, the submarines of China lagging behind the noise techniques of the U.S. and Russia.