South Korea Could Build Nuclear Submarines, But It Shouldn’t
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South Korea Could Build Nuclear Submarines, But It Shouldn’t
Wilson Grossman-Trawick
June 15, 2026
Commentary
South Korea Could Build Nuclear Submarines, But It Shouldn’t
#Defense Industry
#Seapower
#South Korea
Wilson Grossman-Trawick
June 15, 2026
In late May 2026, South Korean Defense Minister Ahn Gyu-back unveiled a roadmap to achieving one of Seoul’s top military acquisition goals: nuclear-powered submarines. This roadmap is heading in the wrong direction.During last month’s inaugural meeting of the Future Defense Strategy Committee, South Korea published its Basic Plan for the Development of Nuclear-Powered Submarines. Chaired by President Lee Jae Myung, the committee was formed to help South Korea build robust, self-reliant defense capabilities. During the event, Lee’s opening remarks underscored the symbolic significance of the nuclear submarine capability and stressed the program’s role in “strengthening the Republic of Korea’s defense industry capabilities.”<br>Despite Lee’s strong rhetoric, the country’s nuclear-powered submarine program risks leading South Korea’s defense industry off course. The high costs and technological complexity of developing a niche capability like nuclear submarine shipbuilding are more costly, complex, and less beneficial than Seoul may realize. Moreover, these dynamics run counter to the export-oriented strategy that has made K-defense an international success and could drain talent and resources from an innovative economic engine. Ultimately, the entire endeavor risks creating unintended budgetary and political pressures that could undermine South Korea’s procurement flexibility and constrain long-term defense spending.
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What South Korea’s Shipbuilding Success Doesn’t Guarantee<br>South Korea’s shipbuilding industry is an international leader, surpassed only by China in market share. However, despite this robust, advanced, and capable — some might even argue superior — shipbuilding industry compared to that of the United States, its expertise, existing infrastructure, and ecosystems are distinctly non-nuclear. While South Korea does have a mature nuclear energy sector — operating 26 reactors to provide roughly one-third of the southern peninsula’s electricity — proficiencies in both sectors are necessary, but not entirely sufficient conditions for a nuclear shipbuilding industry.<br>In fact, Seoul’s success in both sectors likely leads South Korean officials to discount the unique challenges of naval nuclear propulsion, which powers submarines. That’s because the technical expertise required to succeed in both areas is not immediately transferable. Naval nuclear reactors are engineered to meet strict acoustic, shock, and safety standards, all in the confines of a small space capable of operating under some of the most extreme conditions known to man for decades on end. Naval nuclear reactors’ scale, engineering complexity, the no-fail nature of operating underwater at pressure, and overall economics are simply different than their civilian nuclear equivalents. Moreover, nuclear shipbuilding — especially submarine construction — and nuclear vessel operations pose distinct challenges because they require bespoke regulatory, training, and qualification ecosystems and standards that should be developed and maintained alongside existing non-nuclear requirements.<br>Now, that’s not to say that South Korea’s engineers are incapable of achieving such a feat. Rather, I am arguing that nuclear submarine shipbuilding may not enhance South Korea’s defense industry capabilities in the way policymakers claim it will. And its costs risk running South Korea against the shoals.<br>Most importantly, though, building such an industry from the ground up, much less maintaining it over the long term, will take substantial time and resources — and it’s unclear whether the ends justify these expensive means. For example, the U.S. Navy has been constructing nuclear submarines for over 70 years, and it remains a profoundly expensive endeavor — from 2027 to 2031, nearly half (roughly 46 percent) of all new shipbuilding spending will go toward nuclear submarine construction. And this doesn’t include additional funds allocated to right the ailing submarine industrial base.<br>Another example of nuclear shipbuilding’s complexity, even for countries with advanced engineering capabilities, is Japan’s Mutsu: a rare nuclear-powered cargo ship built in the...