The Navy's Evolving Submarines... Is a Nuclear-Powered Submarine Also Being Considered?

Successful Launch of the World's 7th SLBM in 40 Years Since the Introduction of the 1980s Dolphin-Class
Plans to Possess 4000t-Class Submarines Raise Speculation About Nuclear-Powered Submarines

[Image source=Yonhap News]

[Asia Economy Yang Nak-gyu, Military Specialist Reporter] North Korea has carried out missile provocations indiscriminately on land and underwater, drawing attention to domestic response capabilities. In particular, as the SLBM (Submarine-launched Ballistic Missile) successfully launched in South Korea last year is expected to serve as a deterrent against North Korean provocations, the performance of domestic submarines is gaining focus.

The history of the Republic of Korea Navy's submarines began with the introduction of the Dolgorae-class submarines in the 1980s. The first vessel, hull number 051, was commissioned in 1985, followed by hulls 052 and 053 in 1990 and 1991, respectively. However, due to severe aging, after 20 years, hull 051 was decommissioned in 2003, and the remaining two vessels were also retired. The introduction of the Dolgorae-class laid a significant foundation for the history of the ROK Navy's submarines. The Agency for Defense Development (ADD) established the basic concept of submarines, which later became a major driving force for the development of Korean underwater weapon systems.

Subsequently, South Korea's submarine program continued with the Jang Bogo-class I (Type 209, displacement 1,200 tons) and Jang Bogo-class II (Type 214, 1,800 tons) projects in the late 1980s. The Navy currently operates nine Jang Bogo-class I submarines and five Jang Bogo-class II submarines.

With the introduction of submarines, the Navy gained long-range navigation capabilities and expanded operational missions. The first overseas operation was in 1996. At that time, the Choi Mu-seon was deployed to Guam, home to the U.S. Navy submarine base. After arriving in Guam, Choi Mu-seon conducted joint exercises with the U.S. Navy's Kitty Hawk carrier strike group and submarines, and the following year participated in training in Hawaii.

The Jang Bogo-class II submarines have superior key capabilities compared to the Jang Bogo-class I, including underwater operational endurance, stealth, underwater acoustic detection, and onboard armaments. Their most notable feature is the Air-Independent Propulsion (AIP) system, which enables underwater operations for more than 10 days without surfacing. AIP is equipment necessary to generate power during submerged operations when external air supply is impossible. The Jang Bogo-class I lacked AIP, limiting submerged endurance to only 2-3 days.

The military plans to sequentially build the latest Korean submarines, including three Jang Bogo-class II (3,600 tons) and three Jang Bogo-class III (4,000 tons), following the three Jang Bogo-class I submarines.

Submarine names are given after independence activists. The first Jang Bogo-class III submarine is named “An Chang-ho,” after the independence activist Dosan An Chang-ho. Last year, the An Chang-ho successfully launched a submarine-launched ballistic missile (SLBM), making South Korea the seventh country in the world to possess SLBMs. Currently, only six countries? the United States, Russia, China, the United Kingdom, France, and India?operate SLBMs.

The SLBM equipped on the An Chang-ho is the Hyunmoo 4 series missile developed by the Agency for Defense Development (ADD), specifically the “4-4” variant. After SLBM deployment, the military plans to mass-produce the Hyunmoo 4-4 missile. The An Chang-ho carries a total of six SLBMs. Submarines are categorized into batches I, II, and III based on performance upgrades; the An Chang-ho is batch I, and the upgraded batch II and III submarines are expected to carry 10 missiles each.

The batch II project involves a 3,600-ton diesel-powered submarine measuring 89 meters in length and 9.6 meters in width. Compared to the batch I Dosan An Chang-ho, it is heavier and approximately 5.5 meters longer. Combat and sonar systems have also been upgraded. These systems play the most critical roles in submarine operations. The combat system integrates and processes various information necessary for navigation and combat and acts as the brain for weapon operation. It receives and processes target information from sensors such as sonar and radar and manages the entire process from detection to launching torpedoes or guided missiles. The sonar system functions as the submarine’s ears, receiving acoustic information underwater or emitting sound waves to measure the bearing and distance of targets.

Some voices have consistently called for the possession of nuclear-powered submarines as the threat level of North Korea’s military provocations rises.

At the 10th anniversary seminar of the Submarine Alliance last month, former Navy Vice Chief of Staff Kim Pan-gyu (professor at Sejong University) urged the acquisition of “strategic submarines” equipped with “future propulsion systems (large-capacity generators, nuclear power).” He argued that strategic submarines should be secured to operate in the East and South Seas and the East China Sea, assigned long-term missions and strategic target strikes. Considering North Korea’s SLBM-equipped submarines and future nuclear submarine threats, Kim assessed that 3 to 6 strategic submarines are necessary.

Nuclear-powered submarines are presented as a “powerful card” against North Korea’s intercontinental ballistic missiles (ICBMs) and SLBMs equipped with nuclear warheads. Nuclear submarines, called “nuclear subs,” generate power by turning turbines with steam produced from heat generated by nuclear fission. The nuclear fuel (enriched uranium) in the onboard small reactor does not need replacement for 10 years at minimum, and up to 20 to 30 years. Notably, their cruising speed reaches 45 km/h, more than three times faster than conventional submarines. This allows rapid withdrawal after striking targets and swift re-engagement in the shortest time.

The Ministry of National Defense announced in the 2021-2025 Defense Mid-term Plan, which outlines military construction and operation plans for the next five years starting in 2020, that it intends to possess 3,600 to 4,000-ton submarines. This plan is evaluated as considering nuclear-powered submarines. If nuclear-powered submarines are developed domestically, the Navy estimates that a multi-purpose integrated small modular reactor (SMART) can be used, and development can be completed within seven years at a cost of 1.3 to 1.5 trillion won.

However, the Korea-U.S. nuclear agreement poses an obstacle. The Korea-U.S. nuclear agreement stipulates that “South Korea’s uranium enrichment must not exceed 20% and cannot be used for military purposes.” To operate nuclear-powered submarines, South Korea must revise the Korea-U.S. nuclear agreement. This means that nuclear propulsion projects without U.S. support and consent are impossible.

This content was produced with the assistance of AI translation services.