Korean Peninsula: Development of Nuclear-Powered Submarines
The development of nuclear-powered submarines is progressing in both North and South Korea. This occurs amidst shifts in the United States' security strategy in the region.
North Korea's Submarine Program
On Thursday, North Korean state media published an image of what it identified as an "8,700-ton nuclear-powered strategic guided missile submarine." This marks the first public disclosure of the submarine's tonnage and apparently completed hull since North Korea announced its intention to develop nuclear submarines in 2021.
North Korean leader Kim Jong Un stated that the new vessel is intended to bolster the country's defense capabilities in response to what he termed "the negative security situation that has come as present reality." Kim also characterized South Korea's plans to construct its own nuclear submarines as "an offensive act... that must be countered."
South Korea's Pursuit
South Korea has initiated steps to build its own nuclear-powered submarines, following an approval granted by former President Trump in October. A multi-agency task force was established in Seoul last week. South Korea's national security adviser, Wi Sung-lac, indicated that the country plans to negotiate an agreement for the United States to supply it with military-grade nuclear fuel.
This development for South Korea's submarine ambitions aligns with the United States' policy of encouraging allies to assume a greater share of their security responsibilities and increase defense expenditures.
South Korea has pursued nuclear submarine capabilities for decades, citing North Korea's expanding nuclear threats, which have recently extended to maritime capabilities. North Korea has conducted tests of submarine-launched nuclear missiles and claimed to have developed a nuclear-capable torpedo. In October, South Korea's defense minister, Ahn Gyu-back, stated that conventional diesel-powered submarines are less capable than North Korea's nuclear submarines in terms of underwater endurance and speed.
U.S. Regional Expectations
The United States anticipates that future South Korean nuclear submarines will serve a broader regional role beyond countering North Korea. Admiral Daryl Caudle, chief of naval operations of the U.S. Navy, stated during a November visit to Seoul that it is "a natural expectation" for these submarines to be used "to meet our combined goals on what the United States considers to be our pacing threat, which is China."
During an October summit with former President Trump, South Korean President Lee Jae Myung mentioned China, stating, "The limited underwater range of diesel submarines restricts our ability to track subs on the North Korean or Chinese side."
Yoon Sukjoon, a retired South Korean navy captain, commented that it is expected that South Korean nuclear submarines would operate in a wider underwater domain beyond the Korean Peninsula. Yoon noted that waters around the peninsula are shallow for submarine operations. He added that if the South Korean Navy extends its nuclear submarine operations to China, it could contribute to "strategic deterrence against the Chinese Navy's threats in the Indo-Pacific."
South Korea's Diplomatic Stance
Despite these discussions, South Korea has maintained a cautious approach regarding potential military confrontation with China, which is its largest trading partner. President Lee's office later clarified that his remarks to Trump "simply referred to submarines near our waters toward the direction of the North and China," without specifying countries.
This governmental stance reflects public sentiment in South Korea. A recent survey indicated that a majority of the South Korean public believes the country should remain neutral in the event of a significant conflict between the United States and China.
Strategic Considerations and Nuclear Armament
Kim Heungkyu, a political scientist and director of the China Policy Institute at Ajou University, suggested that South Korea (and Japan, which has also indicated interest in nuclear-powered submarines) is concerned about China's increasing regional influence. Kim further noted that as the U.S. reorients its defense focus, its allies may perceive a decreased security commitment in Asia.
A poll conducted by the Asan Institute in March revealed that less than half of Koreans believe the U.S. would respond with nuclear weapons if North Korea were to launch a nuclear attack on the South. Concurrently, a majority of South Koreans expressed support for nuclear armament, even if it entails international sanctions or the withdrawal of U.S. troops.
Kim Heungkyu suggested that in a changing international order in the Western Pacific, South Korea might seek a "survival strategy based on nuclear weapons," viewing nuclear-powered submarines as an "entry point toward a much bigger goal" of nuclear armament.
The South Korean government, which is also discussing access to uranium enrichment and spent fuel reprocessing with the U.S., has denied intentions to develop nuclear weapons. However, Kim stated that the Trump administration was "pushing South Korea and Japan toward the direction of nuclear armament, whether it intends or not."