🚨 Nuclear-Powered Submarines

Today Korean Social News for Beginners | 2025.11.03

0️⃣ End of Korea's Balanced Diplomacy and Strategic Choice Between US and China

📌 New York Times: "Nuclear Submarine Approval Effectively Ends Korea's Balanced Diplomacy"

💬 The New York Times reported that Korea receiving US approval to build nuclear-powered submarines signals "the end of Korea's diplomatic balance." President Lee Jae-myung asked President Trump for nuclear fuel support at the APEC summit, and China strongly objected right after Trump approved it. The New York Times said this decision could be a turning point where Korea fully joins the US security system. President Lee tried balanced diplomacy by expressing his wish to restore relations with President Xi Jinping, but tensions grew as he also strengthened the alliance with the US. Experts point out that it is becoming harder for Korea to balance security and economic dependence between the US and China at the same time.

💡 Summary

• Nuclear-powered submarines are military submarines that use nuclear reactors for power and can operate for long periods without refueling.
• Korea's approval to build nuclear submarines is seen as a signal of full integration into the US security system.
• Korea's balanced diplomacy has reached its limits as US alliance strengthening and China's concerns collide.

1️⃣ Definition

A nuclear-powered submarine is a military submarine that uses a nuclear reactor as its power source. Unlike regular diesel-electric submarines, it uses nuclear fuel, so it can operate for months or even years without refueling. It can stay underwater for long periods, making it much better at staying hidden.

Even without carrying nuclear weapons, nuclear-powered submarines use sensitive nuclear technology like nuclear fuel and reactors, so they have been a major concern for nuclear proliferation internationally. Currently, only a few countries have them: the United States, Russia, China, the United Kingdom, France, and India. Recently, Australia has started developing them with support from the US and UK.

💡 Why is this important?

• They can operate for long periods without refueling, greatly improving their range and endurance.
• They are excellent at staying hidden underwater and provide strong deterrence.
• Because they use nuclear technology, they cause international concerns about nuclear proliferation and diplomatic impact.
• They directly affect Korean Peninsula security and military balance in Northeast Asia.

2️⃣ Background and Issues of Nuclear Submarine Approval

📕 Korea's Reasons for Pursuing Nuclear Submarines

• There is a strategic need to respond to North Korea's nuclear and missile threats. Main background:

  • North Korea continues to develop submarine-launched ballistic missile (SLBM) capabilities.
  • Korea's existing diesel submarines have limits in operation time and detection ability.
  • The naval security environment in Northeast Asia is changing as China and Japan strengthen their navies.
  • There is growing need to strengthen strategic deterrence by securing long-range operation capability.

• There have been technical and institutional constraints. Main issues:

  • Under the US-Korea Nuclear Agreement (123 Agreement), Korea cannot use military nuclear fuel without US permission.
  • Nuclear propulsion reactor technology requires high expertise and is difficult to develop independently.
  • There are constraints from the International Atomic Energy Agency (IAEA) monitoring system and the Nuclear Non-Proliferation Treaty (NPT).
  • It requires huge development costs and a long development period.

📕 US Approval and Diplomatic Impact

• President Trump's approval statement became a diplomatic turning point. Main points:

  • President Lee Jae-myung officially requested nuclear fuel support at the APEC summit.
  • President Trump expressed a positive position and suggested the possibility of technical support.
  • This could mean actual revision of the US-Korea Nuclear Agreement or application of exception clauses.
  • Considering Australia's precedent (AUKUS), it is interpreted as the US's intention to strengthen strategic alliances.

• China's strong opposition appeared immediately. Main reactions:

  • China's Foreign Ministry strongly criticized it as "an act that threatens regional security."
  • They pointed out concerns about nuclear proliferation and the possibility of triggering an arms race.
  • They interpreted it as Korea fully joining the US-led Indo-Pacific strategy.
  • Possibilities of worsening Korea-China relations and economic retaliation have been raised.

📕 Limits of Balanced Diplomacy and Strategic Choice

• Korea's balanced diplomacy has reached structural limits. Main dilemmas:

  • The structure of depending on the US for security while depending on China for economy has continued.
  • As US-China conflict deepens, pressure to choose sides from both has grown.
  • Korea has been repeatedly forced to take positions on THAAD deployment, semiconductor alliances, and Indo-Pacific strategy.
  • This nuclear submarine approval is being accepted as essentially choosing the US side.

• Diplomatic response strategies need to be reorganized. Main tasks:

  • Strategic communication is needed to minimize deterioration of relations with China.
  • It is becoming harder to manage security and economy separately.
  • Korea should pursue diplomatic diversification by strengthening cooperation with third regions like Southeast Asia and Europe.
  • Trust must be built through transparency and responsible behavior in the international community.

💡 Main Issues of Nuclear Submarine Approval

1. Diplomatic camp selection: Full integration into US security system and China's opposition
2. Nuclear proliferation concerns: Appropriateness of using military nuclear technology within the NPT system
3. Economic impact: Possibility of worsening economic relations with China and response plans
4. Arms race: Changes in military balance in Northeast Asia and security instability
5. Technical challenges: Strategic choice between independent development vs. dependence on US technology

3️⃣ Expected Effects and Future Challenges

✅ Expected Security Benefits

• Korean Peninsula defense capability will greatly improve. Main effects:

  • Detection and tracking capability for North Korean submarines and SLBMs will dramatically improve.
  • Long-term operation capability allows continuous monitoring of waters around the Korean Peninsula.
  • Excellent secrecy allows strategic deterrence while avoiding enemy detection.
  • Rapid response and preemptive measures become possible in emergencies.

• The Korea-US alliance will be further strengthened. Main effects:

  • Military technology cooperation with the US will develop to a higher level.
  • Combined operation capability and interoperability will greatly improve.
  • Korea's strategic value in the Indo-Pacific region will increase.
  • Trust in providing extended deterrence (nuclear umbrella) will be strengthened.

✅ Challenges to Solve

• Technical development and safety assurance are essential. Main tasks:

  • Nuclear propulsion reactor design and manufacture require advanced technical skills.
  • Radiation safety and nuclear material management systems must be thoroughly established.
  • Crew education and training programs must be systematically developed.
  • Thorough verification is needed to prevent safety accidents during development.

• Building international trust and ensuring transparency are important. Main tasks:

  • A transparent monitoring system must be established in cooperation with IAEA.
  • International trust must be gained through responsible behavior within the NPT system.
  • Devices are needed to clearly guarantee that nuclear materials will not be diverted to weapons.
  • Concerns must be addressed through continuous dialogue with neighboring countries.

• Huge costs and financial burden must be considered. Main tasks:

  • Nuclear submarine development is expected to cost trillions of won.
  • Continuous costs will occur for operation and maintenance.
  • Priorities may need to be adjusted with other defense projects.
  • It is important to secure public consensus and justification for financial investment.

4️⃣ Related Term Explanations

🔎 US-Korea Nuclear Agreement (123 Agreement)

• The US-Korea Nuclear Agreement is an agreement between the two countries for peaceful use of nuclear energy.
  • The US-Korea Nuclear Agreement is an agreement concluded based on Section 123 of the US Atomic Energy Act, and it defines the scope and conditions of nuclear cooperation between Korea and the US. It was first signed in 1956 and has been revised several times, with the current agreement from 2015 in effect.
  • Main contents of the agreement include: First, it allows only peaceful use of nuclear fuel and nuclear technology. Second, there are restriction clauses on uranium enrichment and spent fuel reprocessing. Third, US nuclear materials cannot be diverted for military purposes. Fourth, US prior consent is needed when transferring nuclear materials to third countries.
  • Regarding nuclear submarine development, this agreement is an important constraint. Nuclear-powered submarines using military nuclear fuel may fall under the military diversion prohibited by the agreement. Therefore, for Korea to build nuclear submarines, separate agreement with the US or revision of the agreement is needed, and President Trump's approval statement is evaluated as suggesting the possibility of easing these constraints.

🔎 Nuclear Non-Proliferation Treaty (NPT)

• NPT is an international treaty to prevent the spread of nuclear weapons.
  • The Nuclear Non-Proliferation Treaty is an international treaty that entered into force in 1970, aiming to prevent the expansion of nuclear weapon states, promote nuclear disarmament, and guarantee peaceful use of nuclear energy. Currently 191 countries have joined, forming the foundation of the international nuclear non-proliferation system.
  • The three pillars of NPT are: First, non-proliferation, which prohibits transfer of nuclear weapons from nuclear weapon states to non-nuclear weapon states. Second, disarmament, which obligates nuclear weapon states to make nuclear disarmament efforts. Third, peaceful uses, which guarantees the right to peaceful use of nuclear energy.
  • Nuclear-powered submarines are in a special position in the NPT system. They use military nuclear fuel but are not nuclear weapons, so they are not clearly subject to treaty regulations. However, they can raise nuclear proliferation concerns as they involve military use of nuclear materials. Therefore, developing countries must work closely with IAEA to ensure transparency and guarantee that nuclear materials will not be diverted to weapons. Korea faces the challenge of developing nuclear submarines while faithfully fulfilling its NPT obligations as a non-nuclear weapon state.

🔎 International Atomic Energy Agency (IAEA)

• IAEA is an international organization that promotes peaceful use of nuclear energy and prevents military diversion.
  • The International Atomic Energy Agency is a UN agency established in 1957 that promotes peaceful use of nuclear energy and monitors to prevent nuclear materials from being diverted for military purposes. Its headquarters is in Vienna, Austria, and currently 175 countries are member states.
  • IAEA's main functions include: First, safeguards, which inspect nuclear facilities and materials of member countries to prevent military diversion. Second, technical cooperation, which provides technical support and education for peaceful use of nuclear energy. Third, setting safety standards for nuclear safety and radiation protection. Fourth, information provision, which collects and distributes scientific and technical information related to nuclear energy.
  • IAEA's role regarding nuclear submarines is complex. Military reactors and nuclear fuel can be excluded from normal inspection targets, creating a kind of blind spot. However, voluntary cooperation with IAEA is important to address nuclear proliferation concerns. Recently, Australia presented a model of ensuring transparency by closely consulting with IAEA while developing nuclear submarines under the AUKUS agreement. Korea will likely need a similar approach.

🔎 AUKUS

• AUKUS is a security cooperation body of Australia, the United Kingdom, and the United States.
  • AUKUS is a trilateral security partnership between Australia, the United Kingdom, and the United States launched in September 2021, aiming to strengthen security in the Indo-Pacific region. The core of the agreement is for the US and UK to provide technology so Australia can possess nuclear-powered submarines.
  • Main contents of AUKUS include: First, transfer of technology to build eight nuclear-powered submarines to Australia. Second, promoting advanced technology cooperation in artificial intelligence, quantum technology, and cyber security. Third, joint development of military technologies such as hypersonic missiles and electronic warfare capabilities. Fourth, strengthening military cooperation in the Indo-Pacific region.
  • AUKUS is evaluated as a US-led security strategy to counter China. Australia will possess nuclear submarines despite being a non-nuclear weapon state, which becomes an exceptional case within the NPT system. Korea's nuclear submarine development is likely to refer to the AUKUS model. However, Australia decided not to enrich or reprocess nuclear fuel and to completely depend on the US and UK, and promised to return spent fuel to the two countries. These conditions serve as mechanisms to ease nuclear proliferation concerns.

5️⃣ Frequently Asked Questions (FAQ)

Q: Do nuclear-powered submarines carry nuclear weapons?

A: Nuclear propulsion and carrying nuclear weapons are separate concepts, and they don't necessarily carry nuclear weapons.

• Nuclear-powered submarines use nuclear reactors as a power source, which is different from carrying nuclear weapons. In fact, many nuclear-powered submarines only carry conventional weapons. First, attack nuclear submarines (SSN) carry conventional weapons like torpedoes and cruise missiles to attack enemy ships or submarines. Second, strategic nuclear submarines (SSBN) carry ballistic missiles to provide nuclear deterrence, which requires separate design and approval. Third, the nuclear submarines Korea is pursuing are attack type (SSN) and will not carry nuclear weapons.
• Korea, as a non-nuclear weapon state, complies with NPT obligations and has clearly stated to the international community that it has no intention of possessing nuclear weapons. Therefore, even if nuclear submarines are developed, they will not carry nuclear weapons and will only be equipped with conventional weapons. However, since using a nuclear reactor as a power source corresponds to military use of nuclear materials, ensuring transparency to address international community concerns is important.

Q: How long does it take to develop nuclear submarines and how much does it cost?

A: Development period is 10-15 years, and costs are expected to be in the trillions of won.

• Nuclear submarine development is a very complex project that takes a long time. First, 5-7 years are needed for technology development and design stages. Nuclear propulsion reactor design, submarine hull design, and various system integration are done. Second, 5-8 years are needed for construction. Reactor manufacture and installation, hull construction, and equipment loading proceed sequentially. Third, 2-3 more years are needed for testing and verification. Sea trials, safety verification, and crew training are conducted.
• In terms of cost, about 3-5 trillion won per unit is expected. The US Virginia-class nuclear submarine costs about $3 billion per unit (about 4 trillion won), and France's Barracuda-class costs 1.8 billion euros (about 2.5 trillion won). For Korea, the first vessel may be more expensive as it includes research and development costs. Also, operation and maintenance costs are much higher than regular submarines, with an additional several hundred billion won expected annually. Therefore, financial burden must be carefully considered and long-term budget plans established.

Q: How much will China's backlash affect the Korean economy?

A: There is a possibility of economic retaliation, but the impact may not be as large as in the past.

• China may take economic retaliation measures like during the THAAD deployment. First, it may strengthen non-tariff barriers against Korean companies or delay customs procedures. Second, it may impose restrictions on Korean tourism and cultural content. Third, it may make the business environment difficult for Korean companies in China. Fourth, it may encourage anti-Korean sentiment and boycotts of Korean products.
• However, unlike the past, there are some mitigating factors. First, Korean companies have reduced dependence on China through supply chain diversification. Major industries like semiconductors and batteries have expanded production bases to Southeast Asia, the US, and Europe. Second, China also depends considerably on Korean intermediate goods and parts, so total sanctions would hurt China too. Third, Korea's status in the global supply chain has risen, making China's unilateral pressure difficult. Fourth, China may refrain from obvious economic retaliation considering international attention. However, the government and companies must prepare comprehensive response strategies for China risk.

Table of Contents

• Go to Guide