Vermilion Tide
For centuries, nations have argued over territorial claims in the South China Sea. Now China may have found a way to further strengthen its island bases in the region: floating nuclear plants. Adding a nuclear dimension introduces radioactive risks that could deter U.S. intervention. To maintain the flexibility to respond to a crisis in the South China Sea and the credibility that it would do so, the United States needs to prepare to fight against a nuclear reactor-hardened adversary. The U.S. needs to raise its forces’ awareness of risks posed by nuclear technology to avoid disaster.
A Floating Nuclear Island
By installing a small modular reactor (SMR) on a seafaring barge, floating nuclear power plants (FNPPs) offer unique solutions to provide power to remote or otherwise challenging areas. Commercially, they can electrify remote communities, power offshore drilling, and fuel desalination. Built in dry dock on a nonpropelled tow barge around 450’ by 100’ in size, FNPPs can be mass produced, quickly deployed, and relocated at a whim across the world.
Despite complex regulatory and safety concerns, the United States, Singapore, Denmark, and South Korea are entering the FNPP market. Each is playing for second place behind Russia. In 2020, Russia’s Akademik Lomonosov became the first modern FNPP to enter sustained operation. However, as promising as their commercial applications may be, their military utility may be greater. Nowhere is this military promise more significant than in the South China Sea.
Importance of the South China Sea
The South China Sea is heavily disputed territory, with China, Taiwan, the Philippines, Brunei, Malaysia, and Vietnam each claiming total or partial sovereignty. China’s irridentist and contested “nine-dash line” demarcates its imposed sovereignty, which covers over 62 percent of the South China Sea and breaches the exclusive economic zones of neighboring states. Consolidating ownership across the nine-dash line, China began in 2013 to artificially construct 27 islands hosting military outposts across the contested Paracel (20) and Spratly (seven) Islands. These islands house anti-ship and surface-to-air missiles, aircraft and airfield infrastructure, electronic warfare systems, and ammunition depots, which both widen and entrench Beijing’s options to “detect and challenge activities by rival claimants.”
Conflict in the South China Sea could ignite over any number of causes. Conflicts with Taiwan, Japan, or even the United States may incite China to restrict the one-quarter of global maritime trade that passes through the South China Sea. In the wake of the operations in Iran, anxieties over energy security (whether domestic or in regional competitors) could lead China to secure or even expand its de facto claim to some of the world’s largest reserves of oil and natural gas. As of 2023, China holds claims to 40 percent and 14 percent of the South China Sea’s oil and natural gas reserves, respectively, though the region is substantially underexplored.
However, the most likely avenue for military conflict remains low-level disagreements that could spiral into larger military aggression, with China using gray-zone encroachment tactics to legitimize military responses against its rivals. This type of conflict is not without recent precedent. The 2024 Second Thomas Shoal incident demonstrated China’s desire to assert its territorial claims through such low-level disagreements, including ramming maneuvers, military-grade lasers, and the use of water cannons. These tensions with the Philippines only deepened in 2025. As China increasingly antagonizes the Philippines, the United States may be drawn into a conflict in the South China Sea through its “ironclad” mutual security commitment to the Philippines under the revived Enhanced Defense Cooperation Agreement.
The Potential Nuclearization of the South China Sea
Any flashpoint could soon face a new, nuclear dimension: floating nuclear power plants. Ambiguity prevails over China’s FNPP intentions in the region. Despite once indicating plans to deploy as many as 20 FNPPs to its facilities in the South China Sea, China suspended these plans in 2023. The combination of unresolved technical challenges, domestic regulatory hesitancy, and strategic ambiguity about international norms created a pause. Yet U.S. officials, including Adm. John Aquilino, confirmed in 2024 that China is still pursuing the program.
While concerns over FNPPs in the South China Sea are nothing new, China’s state-owned nuclear enterprises have recently made significant strides in land-based SMR construction, with the same design once being proposed for an FNPP. With China’s Linglong-1 expected to begin world-first SMR operations within 2026, the time required for China’s sprint to FNPP deployment is significantly narrowed. To expedite developing this technology for FNPP deployment, China could leverage Russia’s deep expertise and its mutual agreement to outcompete the United States. Meanwhile, the commercial FNPP market is gaining steam, with deployment expected by the late 2020s to mid 2030s. The International Atomic Energy Agency also recently stood up the ATLAS initiative to advance the FNPP market. FNPPs hence represent an instance when commercial incentive could drive military opportunity, and not vice versa.
Whatever the status of its FNPP industry, China is poised for fleet-wide deployment in the South China Sea. The heightened security requirements of FNPPs could legitimize China’s gray-zone tactics by setting a perimeter of denial around its territorial claims.
China’s primary incentive to deploy FNPPs to the region is likely to be able to conduct sustained and resilient operations. Weekly sea-lift deliveries of potable water and fuel to island bases are vulnerable to low-cost interventions that can choke these supply lines. FNPPs can operate for two years or more without interruption, hardening an installation’s infrastructure through desalinating seawater and powering the base. Increasing the durability of these forward-postured outposts pushes the United States’ and allied bases further out, impairing rapid response in the theater. However, FNPPs can also serve a direct military purpose.
FNPPs are incredibly energy dense, each generating megawatts of power sufficient to operate a fleet of direct energy weapons. Beyond simply blinding optical equipment, the Chinese LY-1 high-energy laser (HEL) system is potentially capable of intercepting aircraft and anti-ship missiles. High-power microwave weapons, such as China’s Hurricane series, can disable drones further than 3 kilometers away, and the Guangjian HEL series can close the altitude gap by downing drone swarms flying in blind zone altitudes. Limited by power supply, FNPPs offer potentially limitless magazine depth to these emergent capabilities.
The Extent of FNPP Deterrence
Contemporary policy discussions often consider nuclear reactors as a deterrent in and of themselves—tripwires of such radioactive potential as to intimidate states from launching attacks against the sites housing them. FNPPs change the calculus of carrying out a strike and the means to achieve it. While the radiological risk and responsibility lie with China, initiating a radiological incident is a step-change, and one that the United States is unlikely to want to risk.
U.S. strategic objectives may nevertheless require military action against Chinese bases in the region, compelling U.S. forces to confront FNPPs. Allowing a radioactive tripwire to deter any form of engagement would set a dangerous precedent. Accepting this logic would grant de facto immunity to any military facility housing a nuclear reactor, a position that becomes increasingly problematic as countries, including the U.S., explore the deployment of nuclear reactors on military bases. To maintain credibility that the mere presence of FNPPs will not deter the United States, the U.S. military should thoroughly prepare for the potential consequences of operations on or near FNPPs. These preparations take two routes: kinetic strikes and on-site operations.
The U.S. will likely need to inflict enough damage to degrade these outposts’ military effectiveness in the early stages of a conflict in the South China Sea. Given the limited conventional munitions in the Indo-Pacific, efficient kinetic strikes—often targeting key energy infrastructure—become paramount. FNPPs complicate these operations by threatening radiological release if struck, pressuring recourse to much more accurate and expensive strikes on the remaining hardened infrastructure, such as electrical transformers. Kinetic strikes must further contend with second-order effects from collateral damage. For example, debris could clog water intake pipes, preventing the reactor from cooling sufficiently. Given the unique confounding physics, engineering, and operational factors contributing to the Chornobyl incident, a Chornobyl-style accident is highly improbable in either a direct strike or a collateral damage scenario. However, radiation release more akin to the 2011 Fukushima accident is not outside the realm of possibility. A major radiation release could render significant areas of the South China Sea inaccessible to U.S. forces and affect neighboring allied nations.
Kinetic strikes on military FNPPs will raise legal and diplomatic concerns over their precedence, escalation dynamics, and responsibility—arguments prevalent in debates on strikes against civilian nuclear infrastructure. Though Additional Protocol I of the Geneva Convention may permit direct strikes against a military-supporting FNPP, and despite not ratifying this protocol, the United States would not be inclined to risk the international ramifications of doing so. Indeed, a decision to strike an operating nuclear powerplant would have the U.S. join the ranks of Iran and Russia. Such an attack could be internecine as any released radiation would travel subject to the transborder winds and tides to affect civilians, potentially breaching the legal principle of proportionality. Meanwhile, localized damage to islands and reefs claimed by US allies and partners could lead them to rescind occupation on account of the considerable expense required for cleanup, thereby conceding ownership to China. China is unlikely to be dissuaded by any mutual radioactive risk, having demonstrated a willing disregard for nuclear safety in its own land-based reactors. Consequently, China could exploit this asymmetric deterrent-tripwire as a favorable by-product of an FNPP.
An operations planner concerned with this risk asymmetry and constrained by conventional munitions resources may then determine on-site operations as the more strategically favorable option. A small team of operatives could seize control of an FNPP and subsequently relocate it to a secure location. This forward operation would pose significant and protracted risk to U.S. forces, especially during the exposed relocation. However, safely operating (or disabling) a nuclear reactor—especially a novel one of foreign design, potentially sabotaged or damaged—requires extensive expertise. Though an FNPP of proposed Chinese design can shut down in seconds, it will require operational cooling for hours, even weeks afterward, to prevent fuel melt. Whether this cooling can be maintained during a relocation is yet to be determined, to say nothing of the assumed responsibility the United States will then hold while transporting a vulnerable radioactive target.
Concerningly, on-site operations may inevitably be required regardless. Precision strikes against the military outpost could impair operating personnel’s ability or will to operate safely, one of the International Atomic Energy Agency’s seven indispensable pillars of war-exposed nuclear reactors. Though proposed Chinese FNPPs could remain safe for up to 72 hours without operator intervention (a technical requirement widely adopted in the wake of the 2011 Fukushima disaster), challenges unique to FNPPs undermine this promise, while longer-term safety will necessitate on-site caretaker maintenance. Given FNPP mobility, post-strike seizure may likewise be required to avoid the proliferation risk from opportunistic theft. An operations planner must therefore contend with the reality that both an FNPP seizure scenario and a kinetic strike scenario will likely require experienced, on-site operations.
Building Nuclear IQ
The U.S. military will have to raise its forces’ nuclear IQ before taking any action against FNPPs. This requires reemphasizing the nuclear and radiological elements of chemical, biological, radiological, nuclear, and high-explosive (CBRNE) training; planning to integrate civilian experts in operations; and conducting war games to strategize a possible intervention.
Operational planning can account for CBRNE hazards, with most of this operational capacity being held in the U.S. Army’s 20th CBRNE Command and its Nuclear Disablement Team (NDT), as well as the U.S. Marine Corps’ Chemical Biological Incident Response Force. However, the unique maritime and isolated nature of the South China Sea complicates the logistics of deploying elements of these commands as well as essential equipment, such as decontamination chambers. Elements of an Explosive Ordnance Disposal (EOD) company would further be required in the possible event of sabotage. Special Operations Forces with NDT and EOD support are the more likely solution to on-site infiltration.
Experience in such forces is nonetheless limited by capacity. More than two decades of the “war on terror” have deteriorated the salience and expertise of CBRNE that was otherwise prevalent during periods of great power competition. Dealing with a fleet of FNPPs across the 27 islands could overwhelm the already atrophied expertise on hand. This is not a trivial detail, as operating or safely shutting down a nuclear reactor requires specialized training that will have to be developed based on intelligence gathered about deployed designs.
While world-class training exists, the uncertain and unique designs of foreign FNPPs demand a bespoke FNPP curriculum to simulate reality as closely as possible. Updating operations planning documentation to include FNPP scenarios would contribute to this goal. Revising Annex T of Joint Publication 5-0, Joint Publication 3-11, and the CBRN FM 3-11 to account for operations against or involving FNPPs is essential. Meanwhile, increasing the number of CBRNE officers and technicians trained in FNPPs may be needed to retain operational readiness and sustainment. Whether it is procedurally feasible to expect this level of expertise embedded within the forces is debatable, and so integrating civilian experts from the Department of Energy, its national laboratories, and the Nuclear Emergency Support Team may be necessary. Integrating experts is not without precedent. However, the short (three-day) timelines and significant transboundary radioactive hazards are undoubtedly unique to FNPPs, and so operational structures need to be in place ex ante.
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FNPPs could simultaneously harden and sustain Chinese expansionism while posing a transborder radiological threat. With FNPP commercialization expected in the next decade, preparations now will improve effective crisis response in the future. Operations planning increasingly contends with the challenges of entangled dual-capable systems, that is, systems that can serve both a civilian and a military purpose with little or no design change. This planning may soon include FNPP-hardened military bases in the South China Sea. Future war-gaming scenarios must confront the complex diplomatic and legal dimensions of this “tripwire” problem. War-gaming scenarios would benefit from debating the relative merits and risks of kinetic strikes and on-site operations, the international response to a radiological release, and the possible integration of civilian expertise in operations. These preparations would maximize operational success while maintaining the United States’ credibility that it would not be deterred by “FNPP-hardened” targets.
The unique nature of military FNPPs in the contested South China Sea poses a prominent and perhaps the most volatile instance when CBRNE preparations will be essential. Bespoke training dedicated to the particulars of FNPPs must be developed to avoid an international, ecological, medical, and diplomatic disaster. Regardless of stimulus, as nuclear energy gains global traction, adequately preparing U.S. forces for CBRNE operations will become an increasingly salient requisite for operational readiness.
