In November 2016, China announced that it had begun building its first floating nuclear power plant, a project called a ‘top priority’ that would boost Beijing’s ‘strong maritime power strategy’. In February 2017, a government spokesperson for science and technology confirmed that a floating reactor would be operational by 2020 to help fuel China’s offshore activities. While a floating nuclear power plant isn’t a new concept, China General Power Corporation (CGN) announced that it could be used for deep-water oil and gas development in the South China Sea. That idea, should it materialise, would dramatically alter the security landscape of maritime Southeast Asia, and would constitute a serious provocation against ASEAN claimant states. Nuclear power plants, floating or otherwise, require security, safety and safeguards. Those requirements would provide justification for Beijing’s further militarisation of the disputed sea, in turn strengthening its illegal presence and claims in the area.

Chinese installations on its artificial islands are currently powered mainly by diesel generators, supplemented by limited solar and wind power. According to the Global Times, Beijing will deploy floating nuclear power plants in the South China Sea by 2020. CGN reports that China’s construction of several 200 MWt small modular nuclear reactors for maritime use, codenamed ACPR50S, are for the supply of electricity, heat and desalination on far-flung islands and for offshore oil and gas exploration. Significantly, part of the budget for the effort comes from the military.

There are several reasons why these deployments should be blocked before they are yet another fait accompli. First, nuclear power plants would justify further militarisation of the area. Any nuclear reactor, on land or the sea, has to be protected. Since maritime Southeast Asia is a hotbed of piracy and other transnational crime, Beijing would be justified in increasing its military and paramilitary presence in the contested South China Sea. The need for securing nuclear reactors could provide an excuse for the Chinese to deploy even more highly armed Coast Guard vessels, and even PLA Navy ships, in addition to radar and weapon systems on artificial islands.

Second, stationing floating reactors within other nations’ exclusive economic zones (EEZs) is illegal. Most of those areas fall under the UN Convention on the Law of the Sea-mandated EEZs of littoral ASEAN states. Under section 1 of UNCLOS’s Article 56, and according to the July 2016 ruling of the Arbitral Tribunal constituted in The Hague, only ASEAN littoral states have legitimate EEZs that confer “exclusive” sovereign rights over resources around the Spratlys, and can exercise jurisdiction over activities of foreign entities in the area. And, while freedom of navigation in coastal states’ EEZ is guaranteed under UNCLOS, stationing vessels, such as floating reactors, in another country’s EEZ and continental shelf is a different matter.

Finally, nuclear power plants would provide China an instrument to strengthen its presence in disputed waters and to fence off a body of water considered to be the ‘throat of the world.’ Since floating reactors would likely be deployed to power China’s military installations on its artificial islands, the extra energy would boost the coverage and reach of the PLA’s radar and missile systems in maritime Southeast Asia in ways that couldn’t be done through diesel, solar and wind energy sources. There are also hints that China will declare an Air Defense Identification Zone over the South China Sea once it completes its buildup in the area. Nuclear reactors could provide the Chinese the capability to do so. In addition, the presence of nuclear reactors would boost China’s strategic deterrent, as any armed conflict could lead to nuclear meltdown in an important trade route and sea-lines of communication.

It’s time for Washington to be proactive and forward looking in crafting its Asia policy. America has been largely reactive to events happening in the region over the past few years. From Pyongyang’s nuclear activities to Beijing’s island building, disruptions in Asia’s strategic balance have caught Washington off guard. In essence, these disruptions have become a fait accompli, as nothing tangible, short of war, could be done to reverse them.

The Trump administration should anticipate the possibility that China will deploy nuclear reactors in the South China Sea. That would encourage Washington to develop a strategy to not just cope with the scenario after the event, but also to deter or prevent it from happening.

US leadership is critical. Washington should lead discussions on preventive diplomacy, rally regional public opinion against the issue of floating nuclear plants in an area rich in marine biodiversity, support ASEAN claimants’ call for an effective and binding code of conduct that includes provisions against the presence of nuclear materials on disputed domains, and significantly increase the cost that proceeding has to China’s reputation. Collectively, those actions could compel China to publicly disown the idea.

A successful deployment of nuclear reactors in the South China Sea would be a game-changer. It would dramatically alter the strategic calculus in maritime Southeast Asia to the detriment of the rule of law and of America’s position in the region. The US, its Asian partners and allies, and ASEAN have a strong interest in preventing that from happening.

Jeffrey Ordaniel is a resident research fellow at the Pacific Forum-Center for Strategic and International Studies, USA and Ph.D. candidate at the Graduate Institute for Policy Studies, Japan.