| Reframing the Issue: ROK-US Priority and Parallel Korea-France Cooperation Are Not Contradictory

South Korea's pursuit of a nuclear-powered attack submarine (SSN) is no longer an abstract concept or a long-term research agenda. On May 26, 2026, the Ministry of National Defense released the Basic Plan for the Development of the Republic of Korea's Nuclear-Powered Submarine, publicly committing to use low-enriched uranium (LEU) fuel below 20 percent enrichment, to develop and build the submarine domestically, and to comply with nuclear non-proliferation obligations and IAEA safeguards. By setting a target of launching the first vessel in the mid-2030s and achieving operational deployment in the late 2030s, the government has moved the debate over nuclear-powered submarines beyond the question of "necessity" and into the stage of "implementation conditions and procedures."¹⁾

At the core of a nuclear-powered submarine is the conversion of heat generated by a reactor into steam or electricity to produce propulsion—a function entirely distinct from nuclear warheads or nuclear explosive devices. The submarine Korea intends to build is not a nuclear-powered ballistic-missile submarine (SSBN) carrying nuclear weapons, but a nuclear-powered attack submarine (SSN) that is not armed with nuclear weapons. To enhance the international acceptability of a Korean nuclear-powered submarine, Korea must consistently present four principles: a "non-nuclear-armed SSN," "LEU below 20 percent," "prior consultation with the IAEA," and "consistency with the ROK-US alliance."

The core argument of this paper is straightforward. Korea should treat the LEU fuel agreement with the United States as its primary axis, while institutionalizing non-nuclear cooperation with France at an early stage—covering platform integration, safety-design review, maintenance, training, land-based test facilities, and nuclear safety culture. This is not an approach intended to bypass or replace the United States. Rather, it is an approach that complements, rather than bypasses, the ROK–US alliance: by combining the U.S. experience of operating highly enriched uranium (HEU) naval reactors—which differs in character—with France’s experience in LEU naval propulsion, Korea can raise both the likelihood of success and the safety of its nuclear-powered-submarine program.

Nor is it desirable to portray France’s role as merely “secondary” or as a “fallback option.” While the ROK–US framework remains the primary axis for fuel supply, France can offer Korea unique value in such areas as practical operational experience with LEU-based naval propulsion, reactor–hull integration, management of major-overhaul and refueling cycles, training of crew and maintenance personnel, and the cultivation of a safety culture. France is not a substitute for the United States in Korea’s nuclear-powered-submarine program; it is a strategic technology-verification partner that can help Korea complete its LEU-based nuclear-powered submarine more quickly and more safely.

| Why France: The Strategic Value of LEU Naval Propulsion Experience

France is one of the very few Western countries to have operated LEU-based naval nuclear propulsion over a long period. Whereas the United States and the United Kingdom developed HEU-based models favorable to long-life cores, France advanced LEU-based naval propulsion and maintenance systems through the Rubis-class and Suffren-class nuclear-powered attack submarines, the Triomphant-class ballistic-missile submarines, and the aircraft carrier Charles de Gaulle.²⁾

Alain Tournyol du Clos, former head of the Reactor Division at the French Atomic Energy Commission (CEA) and one of the key architects of France's naval nuclear propulsion program,³⁾ has explained that France's choice of LEU was not a decision made at the expense of performance, but a rational choice that weighed safety regulation, maintenance systems, economics, and civil-military nuclear infrastructure as a whole. France had established a safety-regulatory regime requiring inspection of civilian and military reactor components on a ten-year cycle, and designed naval-vessel overhauls⁴⁾ and refueling around that cycle. Moreover, as France expanded its civilian nuclear power generation on a large scale from the 1970s onward, it linked the defense ministry's naval propulsion program as closely as possible with civilian nuclear organizations and infrastructure, thereby reducing costs and sharing operational experience.⁵⁾

An important feature of the French LEU model is that submarines were designed from the outset to be "maintainable nuclear-powered submarines." French submarines incorporate special access structures that enable reactor refueling and maintenance, designed to improve refueling efficiency while preserving the integrity of the pressure hull. This carries an important implication for Korea: if Korea is to build an LEU-based nuclear-powered submarine, it must build maintenance accessibility, radiation protection, spent-fuel management, crew safety, and maintenance-base operations into the design from the very beginning.

Nor should the difference between HEU and LEU be explained simply in terms of performance superiority. HEU's higher energy density gives it an advantage in achieving a relatively compact core and long periods of operation without refueling. LEU, by contrast, lowers the non-proliferation burden and enhances international transparency and explainability, but generally places greater importance on refueling and major-overhaul infrastructure and fleet-readiness management. A report by the Nuclear Threat Initiative (NTI), a nonpartisan, nonprofit U.S. nuclear-security think tank, similarly notes that while naval vessels can clearly be powered by LEU, achieving a long-life core with the same output in the same space presents more difficult design conditions and maintenance/refueling challenges than with HEU.⁶⁾

This is precisely why cooperation with France matters. The United States is the world's foremost operator of naval reactors, but the core of its experience lies in HEU-based long-life cores. Korea, however, has officially chosen a model based on LEU below 20 percent. France is the Western naval power whose operational experience in LEU-based nuclear propulsion is closest to the path Korea has chosen. Korea should secure the institutional foundation for LEU fuel supply and allied operations from the United States, while learning LEU-based platform integration, maintenance, and safe-operation experience from France.

| The Benefit of Korea-France Technical Cooperation: Safety Matters More than Schedule Compression

The real benefit of Korea-France technical cooperation lies less in simple technology transfer than in its effect on Korea's development schedule and safety. If Korea attempts to independently design and verify both the reactor and the submarine platform for its nuclear-powered submarine, the greatest risks are likely to arise not from the reactor itself but from the areas of platform integration and safe operation—the reactor-hull interface, radiation shielding, cooling systems, vibration and noise reduction, land-based test-facility operation, maintenance accessibility,⁷⁾ crew training, and emergency-response procedures. By cooperating substantively with France, which has operated LEU-based naval nuclear propulsion vessels for more than 40 years in these areas, Korea could significantly reduce unavoidable technical trial and error and shorten the overall construction and verification schedule by one to two years or more. More important than schedule compression itself, however, is the ability to build a safer nuclear-powered submarine from the earliest design stage by factoring in maintenance, refueling, radiation protection, and emergency response.

Of course, this benefit does not imply that France would provide core reactor design or nuclear fuel. The realistic focus of cooperation should be non-nuclear areas: platform-integration advisory services, safety reviews, maintenance-system design, land-based test-facility operational experience, and training for crew and maintenance personnel. Korea should therefore maintain the ROK-US LEU fuel agreement as its primary axis while building a technology-verification cooperation framework with France that reduces development risk and enhances safety for Korea's nuclear-powered submarine.

This approach is also persuasive in terms of cost-effectiveness. The most expensive costs in a nuclear-powered-submarine program are not consulting or training fees but the schedule delays and redesign costs arising from design errors, delays in land-based testing, maintainability defects, safety-regulation reviews, and inadequate crew training. By establishing a limited but substantive verification-and-advisory mechanism with France at an early stage, Korea can reduce, on the front end, the trial and error that would otherwise have to be paid for at far greater cost years later. The value of French cooperation should be assessed not by "how much more it costs" but by "how much risk and delay it prevents in advance."

Accordingly, the cooperation Korea should build with France should not take the form of a large-scale technology-transfer agreement but rather a phased, performance-based technology-verification framework. Phase 1 would cover confidentiality and technology-protection procedures; Phase 2, joint working groups on platform integration, maintenance, and training; Phase 3, advisory work on land-based test facilities and safety review; Phase 4, crew and maintenance-personnel training and emergency-response drills; and Phase 5, policy advisory on spent-fuel management and long-term maintenance systems. Structured this way, costs can be controlled while substantive benefits are maximized.

| France's National Interest: Cooperation with Korea as a Strategic Opportunity for France

Korea-France nuclear-powered-submarine cooperation should not be framed as a one-sided request serving only Korea's interests. To win a positive reception from the French government and experts, Korea must clearly explain the strategic, industrial, and normative benefits France itself stands to gain. France is a key European maritime-security actor with overseas territories, exclusive economic zones, and military bases in the Indo-Pacific. Cooperation with Korea on nuclear-powered submarines could allow France to secure a reliable, advanced-technology partner in the Indo-Pacific and substantively extend Europe's strategic autonomy.

First, France could position itself as the leading country in spreading a responsible international model of LEU naval nuclear propulsion. Naval propulsion models that use HEU have always been accompanied by sensitive debate within the non-proliferation regime. Chunyan Ma, a researcher in weapons-systems development and arms control at China's Defense Science and Technology Information Center, and Frank von Hippel, professor of public and international affairs at Princeton University—both of whom have long examined the use of HEU in military reactors critically from a non-proliferation standpoint—argued in a 2001 paper in The Nonproliferation Review that HEU production for naval reactors could create a "military-reactor exemption" loophole in discussions of a Fissile Material Cutoff Treaty (FMCT), and could make IAEA verification more difficult on grounds of military secrecy.⁸⁾

Korea’s LEU-only model, by contrast, is clearly distinguishable from nuclear armament and can secure international transparency through prior consultation with the IAEA. If France cooperates with Korea, France can strengthen the international credibility of its own model - demonstrating that “high-performance naval nuclear propulsion can be achieved while lowering proliferation risk.” This would simultaneously reinforce both France’s technical prestige and its non-proliferation diplomacy.

Second, cooperation with Korea could open new avenues of advanced strategic cooperation within France's naval nuclear propulsion ecosystem. TechnicAtome, which has played a central role in the reactors and nuclear steam supply systems of French naval nuclear propulsion vessels; Naval Group, France's leading defense shipbuilder, with experience in submarine and surface-ship design, construction, and systems integration; the French Atomic Energy and Alternative Energies Commission (CEA), the national nuclear research and development institute; and the École des applications militaires de l'énergie atomique (EAMEA), responsible for naval propulsion and military nuclear-application training, each possesses distinct strengths in nuclear steam supply systems, platform design and systems integration, nuclear research and development, and military nuclear education, respectively. Without requiring the transfer of core reactor design or nuclear fuel, these institutions could provide substantive, high-value cooperation for a Korean nuclear-powered submarine in areas such as platform-integration advisory services, review of maintainability and ease of inspection, safety assessment, land-based test-facility operational advisory services, quality assurance, radiation protection, nuclear safety-culture training, and crew/maintenance-personnel training. This would allow France to share its accumulated LEU-based naval nuclear propulsion experience with a key Indo-Pacific partner, while expanding the international credibility and strategic influence of France's defense and nuclear industries.

Third, the combination of Korean shipbuilding and French naval technology could also offer complementary value in third-country maritime defense markets. Korea has strengths in large-scale shipyards, precision welding, modular construction, schedule management, and price competitiveness, while France has strengths in advanced naval technology, combat-system integration, nuclear-propulsion vessel operating experience, and defense networks across Europe, the Middle East, and the Indo-Pacific. If the two countries cooperate, the relationship could extend beyond nuclear-powered-submarine cooperation alone to submarine MRO, joint surface-ship-and-submarine packages, naval training, nuclear safety services, and third-country defense cooperation.

Fourth, Korea-France cooperation could be an opportunity to give substance to the "Global Strategic Partnership" elevated at the 2026 Korea-France summit. The two countries agreed to deepen strategic dialogue, interoperability, and information exchange in the security and defense field, and to strengthen cooperation on safety, radiation protection, the fuel cycle, and spent-fuel management in the civilian nuclear field.⁹⁾

While this joint statement is not a document committing to the transfer of military naval reactors, it broadens the diplomatic foundation for Korea-France cooperation. If Korea treats France not merely as an "alternative supplier" but as a "strategic co-design partner," France is also likely to view cooperation with Korea as an opportunity consistent with its own national interest and standing.

| U.S. National Interest: Korea-France Cooperation Complements the ROK-US Alliance

Korea's cooperation with France is unlikely to succeed without a convincing explanation to Washington. The United States could react sensitively for three reasons: first, it might suspect that Korea is seeking to bypass U.S. atomic-energy law and congressional procedures; second, it might be concerned that U.S.-origin technology, equipment, nuclear material, or software could be indirectly used in cooperation with France; and third, it might find it unclear how a Korean nuclear-powered submarine would connect to combined ROK-US operations, submarine operational security, and Indo-Pacific naval strategy. The opening line of any explanation to Washington must therefore be: "France is not a substitute for the United States."

Korea should explain that, while it will rely on the United States as its primary channel for LEU fuel supply, it intends to cooperate with France in non-nuclear areas—design, platform integration, maintenance, training, and land-based testing—in order to enhance the safety and reliability of its nuclear-powered submarine. The phrase "technology-verification partner for an LEU-based, non-proliferation-friendly model" is more appropriate than portraying France as an alternative card. Under AUKUS (the U.S.-UK-Australia security partnership), the nuclear material to be provided to Australia is special nuclear material transferred in the form of a fully welded power unit, and is HEU-based which entails non-proliferation controversy.¹⁰⁾

Korea, by contrast, has formally committed to using LEU below 20 percent, building the submarine domestically, foregoing the possession or development of nuclear weapons, and establishing an IAEA safeguards regime - and can therefore present the United States with an alliance model that carries a lower non-proliferation burden. Korea’s nuclear-powered submarine should be explained not as an independent nuclear force operating outside U.S. control, but as an alliance burden-sharing instrument that strengthens combined ROK–US anti-submarine warfare and maritime-deterrence capabilities.

Securing the support of the U.S. administration requires consideration not only of Congress but also of the Department of Energy (DOE), the Department of Defense (DOD), naval-reactor-related agencies, the National Nuclear Security Administration (NNSA), the State Department, and the White House National Security Council (NSC). DOE and NNSA focus on nuclear material, reactor information, and nuclear-security standards; DOD and the U.S. Navy on operational security, anti-submarine warfare, combined operations, and the submarine industrial base; the State Department on non-proliferation diplomacy and alliance politics; and Congress on legal authorization and budget oversight. Korea must manage the concerns of each institution as a single, integrated package.

To this end, Korea should formalize a “clean chain” principle - meaning that U.S.-origin nuclear material, equipment, information, and software will not be used without authorization in Korea– France cooperation, and that the origin of, and access rights to, technology will be managed separately. Concretely, this requires distinguishing ROK–US cooperation networks, Korea–France cooperation networks, and Korea’s independent development network, and establishing a firewall procedure under which any material containing U.S.-origin technology is not shared with the French side without prior U.S. consent. This principle would not only ease U.S. concerns about information protection but also provide France with a basis for recognizing the legal stability of cooperation with Korea.

Korea's package for Washington can be summarized in five formulations. First, LEU-only: Korea's nuclear-powered submarine will use only LEU below 20 percent. Second, no HEU: Korea will not discuss obtaining HEU from the United States or any third country. Third, no nuclear weapons: Korea does not seek to possess or develop nuclear weapons. Fourth, full IAEA consultation: Korea will consult with the IAEA on special safeguards procedures for naval-propulsion nuclear material under paragraph 14 of INFCIRC/153. Fifth, alliance interoperability: Korea's nuclear-powered submarine will operate consistently with combined ROK-US operations, information protection, and anti-submarine warfare networks. These five formulations are designed both to ease Washington's concerns and to clarify Seoul's negotiating objectives.

| Cost-Effectiveness and Concrete Cooperation Mechanisms for Korea-France

Strategic dialogue with France alone will not be sufficient. Two key questions arise in this regard. First, what reciprocal benefit can Korea offer France? Second, given that Korea could also pursue non-nuclear cooperation with the United States, why should it incur the additional cost of building a concrete cooperation mechanism with France? The answer lies in designing Korea-France cooperation not as an abstract friendly relationship but as a cost-effective risk-reduction mechanism.

Korea can offer France four kinds of reciprocal benefit. First, Korea can offer world-class shipbuilding production capacity and schedule management. Second, Korea is a stable partner that can reinforce France's strategic presence in the Indo-Pacific. Third, Korea has an industrial-cooperation base that can be linked to French cooperation in SMRs, nuclear-plant operation, defense, and cyber, space, and maritime security. Fourth, cooperation with Korea offers France an opportunity to strengthen the international legitimacy of the LEU naval nuclear propulsion model and to lead in setting a non-proliferation-friendly naval-propulsion standard.

The reasons for investing additional cost in cooperation with France are equally clear. While the United States is an essential partner for fuel supply and allied operations for Korea's nuclear-powered submarine, France offers a far more directly relevant reference case for the operation, maintenance, and refueling experience of the LEU naval-propulsion model Korea has chosen. U.S. support alone cannot fully bridge the gap between HEU-based long-life-core experience and an LEU-based maintenance/refueling model. Korea should cooperate with France not because "the United States is insufficient," but because "the strengths of the United States and France differ."

To enhance cost-effectiveness, the cooperation mechanism should be designed in stages, beginning with lower-threshold areas of cooperation. First, the two defense ministries should agree on confidentiality and technology-protection procedures for naval nuclear propulsion. Second, the scope of non-nuclear cooperation with TechnicAtome, Naval Group, CEA, and EAMEA should be specified. Third, the list of design data, software, and equipment requiring French export-control authorization—and items unlikely to be authorized—should be identified in advance.¹¹⁾

Fourth, joint working groups should be organized around “safety, maintainability, training, and land-based testing” rather than “nuclear fuel.” Fifth, an annual Korea–France naval nuclear propulsion safety dialogue, or a Track 1.5 expert consultative body, should be established so that government, navy, nuclear-safety authorities, industry, and experts from both countries can gradually build trust. This approach respects France’s strategic standing and institutional sensitivities while achieving Korea’s practical objectives and minimizing U.S. concerns - a balanced approach.

| Korea's Implementation Procedure: From the Government-Wide Consultative Body to a Special Law, National Assembly Support, and an IAEA Package

A nuclear-powered-submarine program is not an ordinary vessel-acquisition project. It is a national strategic undertaking in which the reactor, nuclear fuel, submarine platform, defense acquisition, foreign agreements, information protection, IAEA safeguards, and radioactive-waste management must all move in tandem. The Korean government has already convened, under the Ministry of National Defense, the first meeting of the "Government-wide Consultative Body on Nuclear-Powered Submarines" on December 18, 2025, with relevant ministries and agencies participating, followed by a second plenary meeting on June 10, 2026.¹²⁾

The existence of this government-wide consultative body alone, however, is not sufficient. Going forward, Korea should consider elevating it into a permanent project organization, or a "Jangbogo-N Program Promotion Committee" coordinated under the Presidential Office and the National Security Council (NSC). This body should comprehensively review the ROK-US LEU fuel negotiations and IAEA safeguards consultations, the scope of Korea-France non-nuclear cooperation, preparation of special legislation or statutory provisions, life-cycle costs, the force structure for building four to six vessels, the siting of land-based test reactors and maintenance bases, and spent-fuel management arrangements.

The first domestic legal gateway is Article 60 of the Constitution. If the nuclear-powered-submarine cooperation agreement is merely a research-cooperation memorandum of understanding, it may not require National Assembly consent. However, if it involves nuclear-fuel supply, military-reactor safety, exchange of classified information, long-term fiscal commitments, or spent-fuel management or disposition obligations, it would be politically prudent to pursue National Assembly consent, or at minimum parallel closed-door reporting and budget-approval procedures.¹³⁾

The second gateway is nuclear safety and security legislation. Because Korea's existing Nuclear Safety Act and Defense Acquisition Program Act were developed on the premise of civilian nuclear power plants and general defense-improvement projects, they have limitations in comprehensively covering the safety review of naval military reactors, crew qualifications, nuclear-material accounting, physical protection, accident liability, radioactive-waste management, and submarine decommissioning. A "Special Act on the Construction, Operation, and Nuclear Safety and Security of Nuclear-Powered Submarines," or a special chapter added to existing laws, will therefore be needed.¹⁴⁾

The third gateway is IAEA safeguards. As a non-nuclear-weapon state, Korea is subject to a Comprehensive Safeguards Agreement (CSA). Naval nuclear propulsion is a non-proscribed military activity unrelated to nuclear-weapons development, but because the nuclear material involved may temporarily fall outside the standard application of safeguards, Korea must negotiate a separate arrangement with the IAEA. In the AUKUS case, the IAEA Director General stated that the United Kingdom or the United States could not transfer naval-propulsion nuclear material to Australia until Australia had concluded the necessary paragraph-14 arrangement and implementation mechanisms.¹⁵⁾

Korea should refer to this precedent while clarifying the distinctiveness of its own model. The Australian case is a composite one combining an HEU power unit, the introduction of Virginia-class submarines, and the sharing of U.S./UK naval-reactor information, whereas Korea's case is premised on LEU use and domestic construction. Korea should therefore proactively consult with the IAEA on an "LEU-based, non-nuclear-armed, verifiable naval propulsion model" in parallel with concluding the ROK-US fuel agreement.

| Implementation Roadmap

If the preceding sections examined, respectively, the necessity of Korea-France cooperation, the procedures involved, the logic for persuading the United States, and the scope of French cooperation, this section rearranges that discussion into a chronological implementation plan. Rather than repeating the foregoing discussion, it presents concisely when the Korean government should pursue what, and in what order. The roadmap's guiding principles are: priority for the ROK-US LEU fuel agreement; advance institutionalization of Korea-France non-nuclear cooperation; technology verification based on a Land-Based Test Site (LBTS); treatment of a French fuel option as a secondary, lower-priority consideration and building toward a four-to-six-vessel rotational operating system.

In particular, the opening of the Mun Mu-dae-wang Science Institute could mark an important turning point in the development schedule for Korea's nuclear-powered submarine. While this institute has been publicly described as a research facility for the development and demonstration of marine reactors, its demonstration infrastructure, specialized personnel, and safety-management system could, from a policy and technical standpoint, be linked to serve as the core foundation for land-based verification prior to at-sea installation of the reactor and propulsion system intended for a Korean nuclear-powered submarine. The most hazardous stage in developing a nuclear-powered submarine is not only the reactor design itself, but the process of verifying that the reactor-hull interface, radiation shielding, cooling systems, vibration and noise reduction, emergency-shutdown and accident-response procedures, maintenance accessibility, and crew-training systems all function in an integrated manner under actual vessel operating conditions. If the Mun Mu-dae-wang Science Institute performs these demonstration and verification functions in stages, Korea could substantially reduce the development risk of the reactor and propulsion system for its nuclear-powered submarine, and combined with platform-integration and safe-operation advisory cooperation with France—considerably advance the construction and verification schedule.

​

The meaning of this table is simple. Korea should maintain the ROK-US LEU fuel agreement as its primary axis while institutionalizing, from the outset, cooperation with France focused not on nuclear-fuel supply but on platform integration, maintenance, training, safe operation, and technology verification. In particular, once LBTS-based verification linked to the Mun Mu-dae-wang Science Institute gets underway in earnest, France's LEU-based naval nuclear propulsion experience can help reduce the development risk of Korea's nuclear-powered submarine and advance the construction and verification schedule. It would be realistic to treat the French fuel option only as a medium- to long-term contingency measure to be examined if needed—one that does not conflict with the ROK-US agreement.

| Conclusion: What Korea Needs Now Is a Procedurally Sound Strategic Action Plan

Korea's pursuit of a nuclear-powered submarine has already crossed the threshold of a national strategic undertaking. But a nuclear-powered submarine cannot be secured by declaration alone. The LEU fuel agreement, IAEA safeguards, special legislation, National Assembly support or consent, land-based testing, crew training, maintenance bases, spent-fuel management, and diplomacy toward both the United States and France must all move forward together. Concealing this complexity erodes policy credibility; conversely, institutionalizing it with precision can make Korea's pursuit of a nuclear-powered submarine an internationally acceptable, non-proliferation-friendly model.

This is also where the meaning of Korea-France cooperation lies. France is not a simple detour that could replace the United States. Rather, French cooperation should be understood as a complementary axis to ensure the success of the LEU fuel agreement with the United States, a technology-verification partner for integrating Korea's own reactor and shipbuilding capabilities into a naval nuclear propulsion system, and an institutional partner for long-term maintenance, training, and safety culture. This approach respects France's strategic standing while reassuring the United States, and offers the Korean public and policymakers a realistic path to increasing the likelihood of success for the nuclear-powered-submarine program.

Three policy measures are urgently needed. First, the government-wide consultative body should be elevated to a permanent project organization to integrate and coordinate ROK-US, Korea-France, and IAEA consultations. Second, a special law or statutory provisions on nuclear-powered submarines should be prepared to govern safety, security, nuclear material, radioactive waste, and decommissioning. Third, with the goal of concluding the ROK-US LEU fuel agreement in the first half of 2027, Korea should prepare a persuasion package for the U.S. Congress, DOE, DOD, NNSA, and State Department, while institutionalizing cooperation with France beginning with training, platform integration, maintenance, and safe operation.

A Korean nuclear-powered submarine should not become a simple import of foreign technology. It must be a responsible naval nuclear propulsion model that combines Korea's own reactor and shipbuilding capabilities, the institutional foundation of the ROK-US alliance, France's LEU naval-propulsion experience, and the IAEA transparency framework. Pursued in this way, Korea can secure long-range, long-duration covert operational capability to respond to North Korea's increasingly advanced nuclear and missile threats and a future North Korean SSBN threat, while opening a new path toward becoming a state operating nuclear-powered submarines in harmony with the international non-proliferation regime.

1. Republic of Korea Ministry of National Defense, "Basic Plan for the Development of the Republic of Korea's Nuclear-Powered Submarine," May 26, 2026.
2. Alain Tournyol du Clos, France's Choice for Naval Nuclear Propulsion: Why Low-Enriched Uranium Was Chosen, Federation of American Scientists Special Report, December 2016.
3. Alain Tournyol du Clos is a graduate of the École Polytechnique in Paris, where he specialized in naval architecture and nuclear engineering. He held technical and managerial responsibilities for naval propulsion at the French Ministry of Defense's Naval Construction Directorate and at TechnicAtome. He joined the French Atomic Energy Commission (CEA) in 1999, where he served as head of the Reactor Division, and later served as nuclear counselor at the French Embassy in Beijing.
4. "Overhaul" refers to maintenance work in which machinery or equipment is fully disassembled so that each component can be inspected, cleaned, repaired, or replaced, restoring performance to nearly new condition.
5. Alain Tournyol du Clos, France's Choice for Naval Nuclear Propulsion, pp. iii-4.
6. George M. Moore, Cervando A. Banuelos, and Thomas T. Gray, Replacing Highly Enriched Uranium in Naval Reactors, NTI Paper, March 2016, pp. 1-4.
7. "Maintainability," as used in the military and engineering fields, refers to the degree to which equipment or a vessel is designed so that it can be easily, safely, and quickly inspected, repaired, replaced, disassembled, and reassembled when it malfunctions or requires periodic inspection. In the context of a nuclear-powered submarine, maintainability encompasses such factors as whether maintenance personnel can safely access the reactor compartment, whether radiation shielding and maintenance access routes are appropriately designed, whether the hull structure is designed to allow refueling or replacement of major components, whether faults in the cooling, electrical, and propulsion systems can be quickly diagnosed and repaired, and whether radiation-exposure risk to crew and technicians during maintenance can be minimized.
8. See Chunyan Ma and Frank von Hippel, "Ending the Production of Highly Enriched Uranium for Naval Reactors," The Nonproliferation Review, Spring 2001, pp. 86-89. Chunyan Ma is a researcher in weapons-systems development and arms control at China's Defense Science and Technology Information Center, and at the time of writing this paper held fellowships at the Monterey Institute of International Studies and as a visiting researcher at Princeton University's Center for Energy and Environmental Studies. Frank von Hippel is professor of public and international affairs at Princeton University and a leading expert in nuclear disarmament, non-proliferation, and fissile-material control.
9. Republic of Korea Ministry of Foreign Affairs, "2026 Summit Diplomacy Korea-France Summit"; Élysée, "Joint statement between the President of the French Republic and the President of the Republic of Korea," April 3, 2026.
10. White House, "Letter to Congressional Leaders Transmitting the AUKUS Naval Nuclear Propulsion Cooperation Agreement," August 7, 2024; IAEA, "Director General Statement in Relation to the AUKUS Naval Nuclear Propulsion Agreement," August 15, 2024.
11. France Diplomatie, "Export controls on war material: SGDSN," Contrôler les exportations de matériels de guerre, November 23, 2022; Naval Group, "Prosub: France-Brazil, an unwavering proximity," December 10, 2020.
12. Ministry of National Defense, "First Meeting of the 'Government-wide Consultative Body on Nuclear-Powered Submarines' Discussing General Matters for Nuclear Submarine Construction," Korea Policy Briefing, December 18, 2025; Lee Jong-yun, "Second Government-wide Consultative Body Meeting on Nuclear Submarines Held: 'Foundation to Be Completed Next Year, Special Law to Be Initiated'," Financial News, June 10, 2026.
13. Constitution of the Republic of Korea, Article 60.
14. Nuclear Safety Act and Defense Acquisition Program Act, Korea Ministry of Government Legislation, National Law Information Center.
15. IAEA, "Director General Statement in Relation to the AUKUS Naval Nuclear Propulsion Agreement," August 15, 2024.

※ The opinions expressed in Sejong Focus are those of the author and do not represent the official views of the Sejong Institute.