The Development of Floating Nuclear Power Platforms: Special Marine Environmental Risks, Existing Regulatory Dilemmas, and Potential Solutions

Abstract

Floating nuclear power platforms (FNPPs) are a novel form of nuclear energy infrastructure that is designed to generate electricity in coastal regions, particularly in areas with limited land availability or difficulty in building traditional nuclear power plants. However, the development and deployment of FNPPs have raised significant concerns about their potential marine environmental risks and the adequacy of the existing international regulatory framework for regulating these risks. This research aims to provide a comprehensive analysis of the regulation of FNPPs from an international law perspective, using a policy analysis approach to examine relevant legal instruments and their ability to regulate the environmental risks posed by FNPPs. This study identifies regulatory shortcomings and gaps in the current international legal framework, including pollution regulation dilemmas caused by FNPP positioning, potential conflicts between pollution regulation and freedom of navigation, deficiencies in environmental regulations, problems in the marine environmental impact assessment of FNPPs, and insufficient liability and compensation regime. This research also explores the potential solutions for improving the international regulatory framework, enhancing its ability to effectively address the marine environmental challenges posed by the development and deployment of FNPPs.

1. Introduction

In the context of the global energy transition toward carbon neutrality, the demand for clean energy continues to increase [1,2,3,4,5]. Due to the severe carbon emission problem of traditional fossil fuels and the high construction cost of other renewable energy sources, nuclear energy has become a feasible energy choice in ensuring the power supply for remote islands, offshore drilling platforms, and offshore exploration and development activities. Therefore, in recent years, many countries have endeavored to develop offshore nuclear energy technology, including floating nuclear power platforms (FNPPs).

An FNPP is defined by the International Atomic Energy Agency (IAEA) as a “transportable and/or relocatable nuclear power plant which, when fuelled, is capable of producing final energy products, such as electricity, heat, and desalinated water” [6]. As an effective combination of small modular reactor technology with ships and floating platform projects, an FNPP is often deployed in coastal waters and serves as a transportable nuclear power plant to provide an effective energy supply for remote islands and offshore oil and gas exploration platforms [7]. FNPPs can also be used for seawater desalination, providing large quantities of fresh water to coastal cities that are highly water-scarce.

Several countries have developed or are developing FNPPs. For example, the United States began operating its first FNPP—the Sturgis—in the 1960s. In 2022, the United States Department of Energy provided funding for a three-year research study on FNPPs [8]. Russia began building its FNPP—the Akademik Lomonosov—in 2007, and the platform started operation in December 2019 [9]. China has incorporated the construction of FNPPs into its national energy strategy to address the energy shortage issues that have restricted the country’s maritime activities and plans to deploy twenty FNPPs in the South China Sea [10,11].

Although nuclear energy is low-carbon-emission clean energy [12,13,14,15], FNPPs may have other special marine environmental risks. Deploying and developing FNPPs may not only pose challenges in terms of “safe storage for spent nuclear fuel and decommissioned on-board power plants” but also bring risks of radioactive marine pollution during the daily operation of FNPPs and in the event of major accidents [12]. The swaying, heaving, and navigation of FNPPs may affect marine flora, fauna, and ecosystems. When encountering tsunamis, terrorist attacks, maritime accidents, severe machine damage, fire/explosion, or nuclear leakage, FNPPs may seriously harm both human health and the marine environment. Therefore, a country’s deployment of FNPPs could significantly influence the nuclear safety and marine environment in surrounding waters and the interests of other neighboring countries in the region [16].

While there is currently no specialized convention particularly dedicated to regulating FNPPs, there are several international conventions, protocols, and resolutions that may involve the regulation of FNPPs and their pollution-related issues. In this context, through a policy analysis approach, this study aims to comprehensively examine and analyze the international framework concerning the regulation of FNPPs and their potential marine environmental risks from an international law perspective. This study also critically examines several shortcomings within the existing regulatory framework that hinder its ability to effectively address the marine environmental challenges posed by FNPPs, including pollution regulation dilemmas caused by FNPP positioning, potential conflicts between pollution regulation and freedom of navigation, deficiencies in environmental regulations, problems in the marine environmental impact assessment of FNPPs, and insufficient liability and compensation regimes. On this basis, this research explores possible solutions to improving the existing international regulatory framework in addressing FNPPs’ marine environmental risks.

2. The Literature Review and Analytical Framework

2.1. The Literature Review

The literature on regulating FNPPs and related marine pollution issues concentrates on three primary aspects.

First, existing studies have examined the safety and security challenges posed by developing FNPPs. Some studies have found that the operational safety of FNPPs in the marine environment during extreme weather events can be quite challenging [17]. Scholars have noted that from a nuclear technology perspective when an FNPP is statically tilted in the ocean, some of the FNPP’s safety mechanisms may work improperly, and beyond a certain degree of tilt, the platform’s emergency core cooling system can no longer function, causing severe safety risks [18]. Long-term maintenance to prevent FNPPs and their components from experiencing seawater corrosion is another safety concern. The potential risk of an FNPP being illegally moved or hijacked also poses security challenges to coastal states [17]. Some scholars have noted that despite being designed as zero-discharge plants that store all waste on board for removal during overhaul, they still pose the risk of marine environmental pollution when encountering maritime accidents [19].

Second, existing studies have also examined the regulatory challenges faced by states and their relevant maritime enforcement authorities in regulating FNPPs. The different positioning of FNPPs determines the different regulatory frameworks to which they are subjected. However, scholars and experts have different views on how to define the legal position and status of FNPPs. Some scholars hold the view that as long as FNPPs have actual navigability, they can be regarded as ships [16,20]. Additionally, some studies hold the view that once an FNPP is moored, it is considered an artificial island because of its attachment to the seabed [16,21,22]. Other studies view FNPPs as special artificial facilities [16,23]. Existing research has also focused on the regulatory powers of states. The country deploying an FNPP is considered to have responsibilities for nuclear safety, radiation protection, non-impediment of innocent passage, protection of the marine environment, and nuclear damage compensation [16]. Existing studies have also pointed out the problems of the ambiguity of applicability and the inconsistency among different conventions in the existing international nuclear legal framework in its regulation of FNPPs [24,25]. For more effective regulation of FNPPs, existing studies have proposed countermeasures, including formulating a new international framework, concluding bilateral or regional agreements, harmonizing the systems of international maritime law and nuclear security law, and cooperating to develop safer nuclear technologies for FNPPs [26,27,28].

Third, existing studies particularly examined the political challenges posed by deploying and developing FNPPs. Due to the serious damage caused by nuclear accidents, deploying, operating, and transporting FNPPs in coastal waters, particularly disputed waters, cause objections from other countries. Some studies found that deploying FNPPs constituted an unreasonable interference with the traditional freedom of navigation and marine scientific research [21]. From a geopolitical perspective, Melchiorre (2022) analyzed Russia’s deployment of Akademik Lomonosov in the Arctic and viewed the deployment as a reflection of Russia’s geopolitical ambition to economically develop the Arctic [29]. Nguyen examined the political tensions that might be aroused by China’s deployment of FNPPs in the South China Sea and proposed several ways to mitigate tensions [30].

Existing studies have examined FNPP-related issues from the perspective of multiple disciplines, covering FNPPs’ risk management, safety supervision, environmental impact, political challenges, etc. However, research on pollution control and environmental regulation over FNPPs remains insufficient. Few studies link marine environmental governance regimes with nuclear safety and liability regimes and examine the shortcomings and gaps within the existing international regulatory framework. Especially after the Fukushima Daiichi nuclear accident and Japan’s subsequent plan to release radioactive wastewater into the sea, radioactive marine pollution has attracted widespread attention from the international community, making the deployment of FNPPs in sea areas more environmentally and politically sensitive. Therefore, a more in-depth research is needed to comprehensively examine the existing international framework concerning regulating FNPPs and their potential marine environmental risks.

2.2. Methods, Materials, and Analytical Framework

“International law and institutions serve as the main framework for international cooperation and collaboration between members of the international community in their efforts to protect the local, regional, and global marine environment” [31]. From an international law perspective, this study employs a policy analysis approach to examine the relevant international legal instruments in place covering FNPPs and their related marine pollution issues and analyzes whether the existing international regulatory framework can effectively manage the potential risks and challenges posed by the recent development of FNPPs to the marine environment.

The main materials used for analysis are International conventions, protocols, and resolutions that involve the regulation of FNPPs and their related marine environmental issues. These international legal instruments include the 1982 United Nations Convention on the Law of the Sea (UNCLOS) [32] and a series of relevant international conventions, protocols and resolutions adopted under the auspices of the International Maritime Organization (IMO) and the IAEA (

Table 1. International conventions, protocols, and resolutions concerning the regulation of FNPPs and related pollution issues.

Category	Conventions, Protocols and Resolutions
Nuclear safety conventions	1979 Convention on the Physical Protection of Nuclear Material
	1986 Convention on Early Notification of Nuclear Accident
	1986 Convection on Assistance in the Case of a Nuclear Accident or Radiological Emergency
	1994 Convention on Nuclear Safety
	1997 Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radiation Waste Management (Joint Convention)
Nuclear liability conventions	1960 Convention on Third Party Liability in the Field of Nuclear Energy (Paris Convention)
	1963 Vienna Convention on Civil Liability for Nuclear Damage (Vienna Convention)
	1963 Convention Supplementary to the Paris Convention (Brussels Supplementary Convention)
	1997 Convention on Supplementary Compensation for Nuclear Damage (CSC)
Maritime conventions	1962 Convention on the Liability of Operators of Nuclear Ships
	1965 International Maritime Dangerous Goods Code (IMDG Code)
	1971 Convention Relating to Civil Liability in the Field of Maritime Carriage of Nuclear Material
	1972 Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Convention)
	1973 International Convention for the Prevention of Pollution from Ships (MARPOL)
	1974 International Convention for the Safety of Life at Sea (SOLAS)
	1981 Code of Safety for Nuclear Merchant Ships
	1982 United Nations Convention on the Law of the Sea (UNCLOS)

Source: Authors’ compilation.

). All international legal instruments are collected from the official websites of the United Nations Treaty Collection, IMO, and IAEA.

The remainder of this study is structured as follows. Section 3 reviews the development of FNPPs in practice and analyzes the potential marine environmental challenges posed by developing and deploying FNPPs. Section 4 critically examines whether the international regulatory framework in place is well equipped to address the potential environmental challenges posed by the development and deployment of FNPPs by identifying the regulatory shortcomings and gaps in the existing international regulatory framework. Section 5 explores potential solutions for improving the existing framework to enhance its capabilities in effectively addressing the marine environmental challenges posed by the development and deployment of FNPPs.

3. The Development of FNPPs and Their Marine Environmental Risks

Considering FNPPs’ advantages of providing an effective energy supply for remote islands and offshore platforms with zero carbon emissions and considerably lower costs than land-based nuclear power plants, many countries have endeavored to develop FNPPs. However, deploying, operating, and navigating FNPPs at sea may affect marine flora, fauna, and ecosystems, bringing challenges to the marine environment and marine biodiversity. These environmental challenges, in turn, may even lead to political tensions among the supplying states, host states, and states of transit.

3.1. The Development of FNPPs in Practice

The United States proposed the concept of FNPPs and built the world’s first FNPP—the Sturgis—in the 1960s. The Sturgis was a former World War II Liberty Ship. It was subsequently converted into an FNPP used for housing the MH-1A nuclear reactor to generate electricity for military and civilian use in the Panama Canal area [33]. However, regulatory and environmental concerns led to the demise of the Sturgis in the 1970s [34]. Research shows that from 1968–1975, MH-1A provided 10 megawatts of power in the Panama Canal area before being decommissioned due to high operating costs and the termination of the US Army’s nuclear reactor program [35]. In addition to efforts from the US Army, the first commercial use of FNPPs built by the private sector also originated in the United States [36]. In the 1970s, the Offshore Power Systems Corporation proposed manufacturing a 1200 MW FNPP. Ultimately, however, the plan failed because of opposition from local residents and governments [16,33].

Russia is currently the only country with a functioning FNPP. Akademik Lomonosov, Russia’s first FNPP, was put into operation in the port of Pevek in 2019 and fully commissioned in May 2020, aiming to generate enough power for remote and isolated regions and to provide power for offshore oil and gas platforms located in northern Russia and the Arctic Ocean [35]. The Akademik Lomonosov is “equipped with two KLT-40S reactor units” and “capable of generating up to 70 megawatts of electricity and 50 gigacalories per hour of thermal energy. This power is enough to ensure energy and heat consumption for a city with a population of 100 thousand people” [27]. Akademik Lomonosov is also expected to be used for seawater desalination in regions lacking water resources [27].

China is the third country to plan to develop FNPPs. China has incorporated promoting the development of FNPPs into its nuclear industrial development plans since 2016, aiming to ensure the power supply for isolated island residents, large ships, offshore oil and gas exploration, and similar maritime operation activities [37]. In its most recent nuclear industrial development plans for 2021–2025, China also emphasizes “promoting technological breakthroughs for offshore floating nuclear power platforms” [11,38,39]. China’s major state-owned nuclear and energy enterprises, such as the China National Nuclear Corporation (CNNC), China General Nuclear Power Group, and State Power Investment Corporation, have engaged in developing FNPPs together with the country’s state-owned shipping enterprises. In July 2016, the CNNC signed an agreement with the China State Shipbuilding Corporation (CSSC) to jointly develop FNPPs. In August 2017, China Marine Nuclear Power Development Corporation (CMNPD) was set up, which focused on developing FNPPs and other nuclear-powered vessels [40]. China also plans to deploy twenty FNPPs in the South China Sea to address the energy shortage issues that have restricted the country’s maritime activities [10].

Additionally, several other countries have also put efforts into developing FNPPs or similar offshore nuclear platforms. As noted by the IAEA, similar programs have been carried out and are in various stages of development in the United States, Russia, France, Japan, India, South Korea, and Argentina [6]. Denmark, Vietnam, Singapore, and other countries are also engaged in researching and developing similar FNPPs [33].

3.2. Special Marine Environmental Risks Posed by Developing FNPPs

FNPPs, similar to any other nuclear installation, may also pose risks to the environment [19]. Since the risks faced by FNPPs are a combination of nuclear safety and maritime safety risks, constructing, operating, and deploying FNPPs may encounter more safety and environmental issues than encountered by land-based nuclear power plants, posing challenges to the marine environment and marine ecosystem.

First, the daily operation, maintenance, and refueling of FNPPs may produce spent fuel and radioactive wastes [6,25]. “Radioactive wastes are not biodegradable, nor is there any possibility of removing them from the sea once they have entered it. These substances vary in their effect, but in general, they are absorbed by marine organisms, often becoming concentrated as they move up the food chain, and affecting the growth, reproduction, and mortality of marine life” [41]. Most of the environmental damage caused by the nuclear industry comes from the refueling and disposal of spent fuel and radioactive wastes [42]. For example, the incident at Chazhma Bay in August 1985 involved refueling operations. When submarine K-431 was being refueled, an accident occurred that caused the removal of reactor control rods. The accident during refueling destroyed much of the submarine, resulted in crew member casualties, and caused contamination to spread over a significant area due to ejected fresh fuel [19,43]. Moreover, the daily operation of FNPPs may affect the surrounding marine environment due to potential low-level radiation release and heat dissipation. Thermal pollution from FNPPs may affect marine flora, fauna, and ecosystems in nearby waters because water temperature change can fatally damage marine life, change the chemical composition of seawaters, and cause ecological imbalance [16,22,44]. Additionally, even the deployment of FNPPs in the ocean per se may have environmental impacts on the surrounding marine geography and ecology; these impacts include changing sediment deposition patterns in nearby waters and the unusual siltation and erosion of coasts, deltas, and beaches. FNPP accessory devices also have similar problems. For example, underwater power cables could pose disturbances to the seabed, adversely affecting marine flora, fauna, and ecosystems [35,45].

Second, when FNPPs encounter special circumstances (such as extreme weather, collisions, external threats, operational errors, severe machine damage, and fire/explosion) [46], FNPPs’ environmental risks may heighten. Once a severe accident occurs, for example, colliding with ships navigating with high navigation speed, colliding with rockets, or sinking in shallow water, there are risks of leaking radioactive pollutants into the marine environment. In the event of accidents or other catastrophic events, “nuclear damage could be of an extreme magnitude” [6]. Leaked radioactive materials from FNPPs could then quickly disperse into the ocean, potentially contaminating large areas of the sea and causing detrimental cross-border effects as well as serious harm to both humans and marine ecosystems [6,47]. Moreover, maritime security threats, such as terrorist attacks, armed intrusions, and the hijacking of ships, may also endanger FNPPs and surrounding waters, making physical protection against external threats vital for the deployment of FNPPs [48]. In addition, without effective training for crew members on board, human error-induced accidents are more likely to occur on FNPPs. Research shows that human errors are responsible for most ship accidents [49]. The offshore working environment on FNPPs is more stressful for humans and, compared with land-based nuclear installations, often lacks enough human resources; consequently, operators of FNPPs are more prone to making errors, inducing nuclear accidents [48]. Research shows that some radioactive leakage from nuclear-powered ships has resulted in emergency dumping [50].

Third, once the meltdown of nuclear reactors occurs, it may cause more serious maritime environmental disasters than land-based nuclear installations do. If a core meltdown were to occur at a land-based nuclear installation, “the radioactive core debris would melt into the rock below the plant, and the heat would melt the rock into an insulating glaze around the core. The radioactivity would be released slowly into the environment, which would allow for measures to counteract the radioactivity” [22]. However, if a core meltdown were to occur at an FNPP, “the radioactivity would be released immediately into the hydrosphere and would disperse more quickly. The impacts would be larger and more stressful, particularly on those species and organisms which had a low tolerance to radioactivity” [22]. Consequently, in the case of a core meltdown, the overall risks and consequences of FNPPs would be greater than those of land-based nuclear plants, as environmental pollution would become a global instead of a local problem [22,30,35].

How to prevent FNPPs from becoming the Chernobyl at sea has become an issue of concern to all countries and the whole international community. Once a nuclear incident occurs at an FNPP, its radioactive pollution to the marine environment would not be confined by national borders, making radioactive marine pollution a global problem. Particularly when FNPPs are deployed in disputed waters or in sea areas beyond national jurisdictions, FNPPs may not only arouse opposition from other countries but also cause political and diplomatic tensions among states [16,30]. FNPPs’ potential marine environmental risks make their deployment quite sensitive and may even induce political and diplomatic tensions among states [16,30]. The interests of neighboring countries in the region can be affected by the deployment of FNPPs. For example, countries with fisheries and tourism industries may see their livelihoods impacted by potential environmental change or damage caused by FNPPs. Countries that rely on shipping lanes may also be affected by potential navigation hazards. Additionally, countries with competing territorial claims may view the FNPP deployment as a threat to their interests in the region. Deploying FNPPs in waters with sovereign disputes may also induce the problem of overlapping jurisdiction and overlapping application of different state laws in the regulation of FNPPs, creating regulatory disputes and chaos. Because of these reasons, China’s plan of deploying twenty FNPPs in the South China Sea has aroused concerns from its maritime neighbors, such as Vietnam and the Philippines. These neighboring countries claimed that the deployment of FNPPs in disputed waters would undermine their sovereignty and called for a collaborative approach in which the potential effects on navigation safety and the marine environment are evaluated and taken into account before any deployment is approved [30,51,52].

4. Dilemmas of the Existing International Regulatory Framework in Addressing FNPPs’ Marine Environmental Challenges

Deploying and operating FNPPs often involve multiple countries. FNPP-related marine environmental challenges cannot be effectively regulated through the efforts of a single country [31]. Therefore, an effective international regulatory framework is essential in addressing FNPPs’ marine environmental challenges. While there is currently no specialized convention particularly dedicated to regulating FNPPs, there are several international conventions, protocols, and resolutions that may involve the regulation of FNPPs and their pollution-related issues. However, there are still several shortcomings within the existing regulatory framework that hinder its ability to effectively address the marine environmental challenges posed by FNPPs. The existing international regulatory framework is composed of both the nuclear convention system formulated under IAEA auspices and the maritime convention system formulated under the auspices of the United Nations and IMO (Table 1). The lack of sufficient coordination between the two legal systems creates fragmentation and complexity in the international community’s response to radioactive marine pollution. Efforts have been made to resolve the difficulties and conflicts arising from the concurrent application of nuclear and maritime conventions [53,54]. However, the 1971 Convention on Civil Liability for Maritime Carriage of Nuclear Material has not been widely adopted, with only seventeen contracting parties and limited state participation [55].

4.1. Controversies in Pollution Regulation Caused by FNPP Positioning

In international law, there are controversies in terms of the positioning of FNPPs [6,16,20,21,22,23]. The different positioning of FNPPs—ships, artificial islands, or artificial facilities or structures—and related controversies may make FNPPs’ pollution regulation encounter dilemmas under the existing international regulatory framework [26].

The 1972 International Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Convention) [56] regulates only the dumping of “wastes or other matter from vessels, aircraft, platforms or other man-made structures at sea” (London Convention, 1972, Article 3). The discharge of wastewater from structures on land is excluded from the application scope of the London Convention. However, if FNPPs are positioned as artificial islands, their pollution would then be treated as land-based pollution, and their regulation under the London Convention will be in dispute. The 1973 International Convention for the Prevention of Pollution from Ships (MARPOL) [57] also regulates vessel-source pollution, but the convention defines a ship as “a vessel of any type whatsoever operating in the marine environment and includes hydrofoil boats, air-cushion vehicles, submersibles, floating craft and fixed or floating platforms” (MARPOL, 1973, Article 2). However, if FNPPs are positioned as artificial islands, structures, or facilities, MARPOL’s regulation over FNPPs would be controversial. The 1974 International Convention for the Safety of Life at Sea (SOLAS Convention) [58] incorporates a special chapter for the safety regulation of nuclear ships. However, if positioned as artificial islands, structures, or facilities, SOLAS may face the same regulatory dilemma as MARPOL.

Furthermore, UNCLOS has established different rules for “land-based pollution” and “vessel-source pollution”, as well as different rules for “nuclear-powered ships and ships carrying nuclear substances” and “artificial islands, installations, and structures.” Controversies in FNPP positioning also imply controversies in applying these different rules [16,26].

Additionally, in terms of nuclear safety and liability conventions, as many of the conventions confine their application scope to land-based nuclear installations, some scholars disagree with the broader interpretation of the application scope in these conventions and argue that they apply only to land-based nuclear installations [24]. These disputes pertaining to the application scope pose practical difficulties for regulating FNPPs under existing nuclear safety and liability regimes.

4.2. Potential Conflicts between Freedom of Navigation and Deploying and Regulating FNPP

Deploying FNPPs and, subsequently, regulating them to prevent and control pollution may inflict concerns for potential conflicts with the freedom of navigation. Deploying FNPPs may affect other countries’ navigation, fishing, and marine scientific research activities in surrounding waters, although some countries may regard a country‘s deployment of FNPPs in its territorial waters as eroding existing sea lanes and impeding the freedom of navigation. Nevertheless, as long as the deployment of FNPPs does not impede the innocent passage of other countries, the deployment of FNPPs within a country’s territorial waters does not generally conflict with the principle of freedom of navigation [16]. Particularly considering the limitations of freedom of navigation, as pointed out by some scholars, the deployment state may have a right to suspend other ships’ innocent passage when FNPPs are deployed within its territorial sea [23]. Meanwhile, other states also have a right to require the deployment state to designate specific sea lanes for them to ensure their navigational rights [23].

Deploying FNPPs in the exclusive economic zones or in waters above the continental shelf may also inflict relevant debates. Under UNCLOS, in the exclusive economic zones or in waters above the continental shelf, coastal states are allowed to establish reasonable safety zones when necessary around the artificial islands, installations, and structures “to ensure the safety both of navigation and of the artificial islands, installations, and structures” (UNCLOS, 1982, Articles 60, 80). It implies that if FNPPs are positioned as “artificial islands, installations, or structures” rather than ships, coastal states that deploy them thereby will have the right to establish safety zones in the exclusive economic zones or in waters above the continental shelf. UNCLOS allows the coastal state to determine the breadth of the safety zones within a distance of 500 m around the artificial islands, installations, or structures. When determining the breadth of the safety zone, coastal states are required to consider “applicable international standards” (UNCLOS, 1982, Article 60). If authorized by the “generally accepted international standards or as recommended by the competent international organization”, the breadth of the safety zones can exceed 500 m (UNCLOS, 1982, Article 60). However, in terms of FNPP deployment-related safe zone issues, there is a lack of relevant “applicable international standards”, “generally accepted international standards”, or recommendations from the IMO. Given the lack of relevant international standards and guidelines, if coastal states are allowed to have discretion in deploying FNPPs, “it is likely to result in safety zones with a wide variety of breadth, which may negatively affect navigation, fishing and marine scientific research activities in surrounding waters” [59]. Due to the lack of relevant international standards, if coastal states vigorously promote developing and deploying FNPPs in the ocean, such actions “could even lead to a potential effect of closing off large areas of the sea to navigation” [60].

Deploying FNPPs and establishing relevant safety zones, in turn, may also affect coastal state control. If the deployment state deploys FNPPs in its coastal waters, problems will not arise in terms of the regulation of these FNPPs. However, in many cases, the deployment of FNPPs may involve multiple countries, including the licensing/supplier states, the host/deployment states, the flag states, and the transit states (whose territorial waters through which FNPPs are to be transported) [6]. In such cases, effective coordination among these states would be critical to effectively regulating FNPPs and their marine environmental risks. In particular, if an FNPP is deployed in disputed waters in which sovereignty disputes exist among neighboring states, regulatory frictions or even political disputes may arise.

4.3. Deficiencies of Environmental Regulation

Regulating FNPP-related environmental risks is governed by a series of existing conventions. However, the existing international regulatory framework still has many shortcomings. In particular, the FNPP “export/outsourcing scenario” [6] involves the interplay among the supplier states, the host states, and the third-party states through the territorial waters of which the FNPPs would be transported. In such a scenario, the issue of separation of coastal and flag state regulations may arise. The existing international regulatory framework does not solve insufficient regulation due to the flag of convenience, nor does the framework impose clear pollution control responsibilities on deployment states when they deploy FNPPs in coastal waters. Consequently, FNPP-related marine environmental risks may not be effectively regulated.

Under the existing international regulatory framework, coastal states may play only a limited role in regulating FNPPs. Regulating FNPPs relies mainly on the flag state. Although UNCLOS specifically stipulates coastal states’ regulatory measures for nuclear ships passing through their territorial waters (UNCLOS, Articles 22–23), coastal states’ regulatory measures over nuclear ships are largely limited to the territorial sea. The navigation of FNPPs in the exclusive economic zones is considered to enjoy the freedom of navigation, leaving the regulatory power over FNPPs to the flag states [42]. SOLAS has introduced a special chapter to ensure the safety of nuclear ships by requiring the flag states to “take measures to ensure that there are no unreasonable radiation or other nuclear hazards at sea or in port, to the crew, passengers or public, or to the waterways or food or water resources” (SOLAS, 1974, Chapter VIII, Regulation (6). However, flag state control obviously has deficiencies arising from ineffective regulation due to the problem of the “flag of convenience” [59]. Experience shows that “flag states often fail to provide adequate oversight with so-called ‘flags of convenience’ offering low-cost registration, loose environmental and operational requirements, and weak enforcement” [61]. The 1994 Convention on Nuclear Safety [62] establishes a rather comprehensive regulatory framework for the operational safety of nuclear installations. However, confined by its application scope, the convention is considered to regulate only land-based nuclear installations, and its applicability to FNPPs in navigation is uncertain. As transportable platforms at sea, the navigation of FNPPs from supplier states to deployment states may involve different marine zones, including the territorial seas, exclusive economic zones, or even the high seas. Therefore, a more effective international regulatory framework for FNPPs and their marine environmental risks is necessary to balance the regulatory powers and responsibilities of multiple states in different maritime zones.

Moreover, implementing pollution prevention obligations for the deployment state may encounter practical difficulties within the current international regulatory framework. FNPPs’ manufacturing and transportation to their final deployment involve multiple states. In terms of pollution control regulation, the existing nuclear conventions and maritime conventions focus largely on the regulatory powers and obligations of coastal states and flag states. Although, in most cases, coastal states are the FNPP deployment states and are, thus, allowed to deploy FNPPs in their coastal waters and bear corresponding pollution prevention obligations, there are several exceptions that would lead to disputes in practice. For example, deployment states rent FNPPs from other supplier states to solve energy shortage problems and deploy FNPPs in disputed waters, or deployment states purchase FNPPs from other supplier states, and FNPPs’ delivery must pass through sea areas under jurisdictions of other states. In these circumstances, problems arise—can the coastal state hold the deployment state accountable for the FNPPs’ unauthorized passage or deployment in disputed waters? Does the deployment state have a duty to regulate the environmental risks of FNPPs? When marine pollution accidents occur, can the deployment state be required to bear responsibility and make compensation? Since the deployment state may be neither the flag state nor the coastal state, the existing international regulatory framework that takes coastal state and flag state regulation as the main regulatory approaches may encounter problems when these exceptional situations occur, hindering prompt ex ante response and effective ex post accountability and relief. While environmental due diligence obligations outlined in UNCLOS and post-Rio Declaration environmental law may be imposed on states deploying FNPPs [63,64], implementing these obligations may prove challenging in practice. “The due diligence standard has sometimes been criticized as elusive and too flexible” [65,66], leaving many issues unanswered. Japan’s nuclear wastewater discharge after the Fukushima nuclear disaster provides such a reflection on FNPPs’ nuclear accidents. Can the deployment state legally discharge radioactive materials into the ocean following a nuclear accident on board FNPPs? Or is the discharge activity per se a violation of due diligence obligations? What are the criteria used to determine whether a state has fulfilled its due diligence obligations and whether the presence of environmental damage alone constitutes a breach of such duty [67]? Does the authorization and guidance from the IAEA make the deploying state’s discharging activity compliant with due diligence obligations even if it results in ocean pollution? Is authorization from the IMO also necessary due to the potential impact of FNPPs on the marine environment? Most importantly, does the adoption of a fault-based due diligence approach undermine the principle of no-fault liability established by the nuclear liability conventions?

4.4. Problems in FNPPs’ Marine Environmental Impact Assessment

FNPPs have environmental risks throughout their life cycle. Whether in operation or during transportation, FNPPs may affect the marine environment and marine ecosystem due to the potential discharge of radioactive waste or nuclear leakage [16]. As ruled by the International Court of Justice in the Pulp Mills case, undertaking “an environmental impact assessment where there is a risk that the proposed industrial activity may have a significant adverse impact in a transboundary context” has been considered “a requirement under general international law” [68]. Hence, to prevent the operation of FNPPs from harming the marine environment, the deployment state should implement an environmental impact assessment for FNPP deployment. The current international conventions involving FNPPs’ marine environmental impact assessment can be divided into the following four main categories: (1) nuclear safety conventions; (2) UNCLOS; (3) conventions aiming to address pollution from ships; and (4) conventions concerning environmental impact assessment of transboundary harm [69]. However, under the existing international regulatory framework, FPNP-related marine environmental impact assessments may face difficulties in practical implementation.

First, existing nuclear safety conventions, such as Convention on Nuclear Safety and Joint Convention [70], stipulate the safety assessment requirements for nuclear installations, which provide a basis for the environmental impact assessment of nuclear facilities. However, as mentioned above, the controversial issue of these conventions’ application scope makes their application to FNPPs difficult. Additionally, these conventions set assessment requirements only for “safety” and do not clearly specify the possible “environmental” impact requirements of nuclear installations. In addition, these conventions only require the deployment state to disclose information to “contracting parties in the vicinity” to facilitate their safety assessment without considering the FNPP’s potential impact on international commons, such as the high seas and polar areas.

Second, UNCLOS specifically stipulates the marine environmental impact assessment requirement. Article 206 provides that “when states have reasonable grounds for believing that planned activities under their jurisdiction or control may cause substantial pollution of or significant and harmful changes to the marine environment, they shall, as far as practicable, assess the potential effects of such activities on the marine environment” (UNCLOS, 1982, Article 206). This is a direct state obligation, and relevant general marine environmental impact assessment obligation also covers private activities. However, there are no definitions for “substantial pollution” or “significant and harmful changes”, thus implying a great degree of discretion in implementing marine environmental impact assessments. Since FNPPs are considered to have less impact than land-based nuclear installations on human beings because their locations are often far from densely populated areas on land, they may enable the deployment state to claim a lack of “substantial pollution” or “significant and harmful changes” [71].

Third, Annex II of the London Convention establishes a detailed procedure for assessing wastes or matters that may be considered for dumping. However, as mentioned above, the convention only regulates dumping “from vessels, aircraft, platforms, or other man-made structures at sea” (London Convention, 1972, Article 3). If FNPPs are positioned as artificial islands, they may not be covered by the convention. Furthermore, the convention excludes the disposal of wastes derived from ships’ normal operations from regulation. If the radioactive materials discharged from FNPPs can be considered as derived from normal operation, the procedure for the environmental impact assessment would not apply.

Fourth, there are also conventions covering environmental impact assessment pertaining to transboundary harm. The 1991 Convention on Environmental Impact Assessment in a Transboundary Context (Espoo Convention) is one of the key instruments [72,73]. It thoroughly outlines the substantive and procedural requirements for environmental impact assessment. Affected states have a right to be notified and to participate in the assessment process [74]. However, the problem is that the impacts of FNPPs on the marine environment are not confined to national borders, and it is difficult to determine the scope of affected states [73].

Most importantly, there are also difficulties in determining the sufficiency and adequacy of environmental impact assessments related to the deployment of FNPPs by international judicial institutions. UNCLOS does not provide specific guidance on the scope and content of marine environmental impact assessments and does not refer to any internationally agreed rules and standards for these assessments [75,76]. Neither the scope nor content of environmental impact assessments are specified in general international law [16,77]. Consequently, the specific requirements of an environmental impact assessment may vary depending on the case and rely largely on the deployment state’s domestic laws [68,77,78], resulting in difficulties for international adjudication bodies in determining the sufficiency and adequacy of environmental impact assessments related to FNPP deployment. Additionally, assessing the adequacy of environmental impact assessments related to the deployment of FNPPs may involve the evaluation of scientific evidence; however, judges and arbitrators “may not necessarily have sufficient scientific expertise” for such evaluation [75]. As the scholar commented, “the lack of an adequate mechanism for transboundary environmental impact assessment at the onset of the conflict under UNCLOS” makes the international adjudication bodies “incapable of addressing the root cause” of the case [75].

4.5. Shortcomings in Liability and Compensation Regime

When FNPPs cause radioactive marine pollution, effective accountability for those responsible parties and “access to justice based on prompt and adequate compensation” for those victims, in particular transboundary victims, would be the foundation that underlies the whole relief process [79]. Several international maritime conventions and international nuclear liability conventions have established liability and compensation frameworks for transboundary radioactive damage. However, in regard to the marine pollution caused by the daily operation of FNPPs or the sudden occurrence of nuclear accidents, victims might face practical problems seeking relief under the existing international legal frameworks.

First, the different positioning of FNPPs and inconsistent principles and approaches for liability channeling may lead to confusion in determining the civil liabilities and compensation for FNPP-induced pollution damage. As mentioned above, in international law, there are controversies over the positioning of FNPPs in terms of whether they should be considered ships, artificial islands, facilities, or structures [6,16,21,22,23]. If defined as land-based facilities or structures, FNPP-related pollution liability and compensation can be solved in accordance with nuclear liability conventions. However, if defined as ships, the application of these liability conventions would face controversies. Although the 1962 Convention on the Liability of Operators of Nuclear Ships (Brussels Nuclear Ship Convention) addresses nuclear ship-related liability issues, the ratification of the convention has become deadlocked and failed to enter into force [53,80].

Second, under the existing nuclear liability regime, the liability and compensation issues for FNPP-related pollution damage may also have problems. Under existing nuclear liability conventions, compensation is often premised on the damage induced by nuclear incidents. However, marine pollution may also be produced by the daily operation of FNPPs, the liability and compensation for which are not effectively covered by the existing nuclear liability conventions. Even the application of basic principles of the nuclear liability regime, namely, channeling exclusive liability to the operator, imposing supplementary liability to the installation state, establishing exclusive jurisdiction of the courts in the state where a nuclear accident occurs, setting limitations for the liability, etc., could face problems in the case of FNPPs. The existing nuclear liability regime imposes exclusive liability on the operator, which may make the “supplier and other service providers free from liability and compensation” [81]. Moreover, if FNPP pollution occurs in disputed waters or waters beyond the deployment state’s jurisdiction, only allowing victims to bring lawsuits to the courts of the deployment state may impede victims’ access to prompt and effective relief. Additionally, the limitation of liability may keep the amount of compensation from meeting the demand of the marine environment and ecological restoration.

Third, under existing international laws, victims’ access to adequate compensation also faces difficulties. The rule that “every state has obligations not to knowingly allow its territory to be used for acts contrary to the rights of other states and to ensure that activities within its jurisdiction respect the environment of other states or areas beyond its national jurisdiction” has been recognized in a series of important cases adjudicated by the International Court of Justice [82,83,84]. Under this rule, compensation for transboundary damage is often dependent on a state’s “knowledge and foreseeability of the risk” [66]. Therefore, marine pollution caused by FNPPs due to unforeseen reasons, such as natural disasters may not necessarily be fully compensated. Another element that may limit compensation is the “significant damage” threshold. International law for transboundary damage often requires the damage to be significant or material enough to render the victims a right to compensation [85]. Failure to prove the significance of pollution would deprive the affected parties of compensation [66,86]. As a result, these legal thresholds may obstruct transboundary victims’ efforts to obtain compensation [54,87].

5. Potential Solutions for the Existing Regulatory Dilemmas

Developing and deploying FNPPs may pose many challenging issues to the international community in terms of nuclear safety maintenance and radioactive marine pollution prevention and control. The existing international regulatory framework has several shortcomings and insufficiencies in coping with these challenges. Therefore, the existing framework must be improved to address the potential marine environmental challenges brought by developing and deploying FNPPs.

5.1. Resolving the Convention Application Dilemma

As mentioned above, the different positioning of FNPPs has caused serious difficulties in pollution regulation under the existing international regulatory framework. Therefore, resolving these problems requires improving the existing international institutional framework.

A feasible way is to extend the application scope of existing nuclear safety and nuclear liability conventions to cover FNPPs by fostering interpretative developments. Whether existing nuclear conventions are applicable to FNPPs depends on whether FNPPs can fit into the term “nuclear installations” as defined in these conventions. When how to position FNPPs is highly controversial in theory and in practice, a feasible solution that may be considered is to expand the application scope of existing nuclear safety and nuclear liability conventions [26]. FNPPs can be included through the revision of the Paris Convention or the Vienna Convention. Both conventions contain the possibility of expanding their scope to include FNPPs. According to the Paris Convention [88], a “nuclear installation” includes any “other installations in which there are nuclear fuel or radioactive products or waste” as determined by OECD (Paris Convention, 1960, Article 1). The Vienna Convention [89] also added any “other installations in which there are nuclear fuel or radioactive products or waste”, as determined by IAEA (Protocol to amend the Vienna Convention on Civil Liability for Nuclear Damage, 1997, Article 2). Therefore, OECD and IAEA can exercise their authority and incorporate FNPPs into the existing nuclear convention system [26]. By expanding the scope of application of existing conventions to include FNPPs, their safety regulation, pollution prevention, control, pollution liability, and compensation can be resolved through existing international conventions while avoiding controversies in FNPP positioning. However, this method may encounter several problems, including whether the expansion of the application scope is mandatory and applicable to all contracting parties. Will the reluctance of some contracting parties, in particular those FNPP deployment states, to accept such a change of scope lead them to withdraw from the conventions, thereby undermining rather than reinforcing the existing international regulatory framework?

Another way that could be considered is to establish specialized bilateral/regional agreements or international conventions pertaining to FNPPs to more thoroughly solve issues in terms of their safety regulation, pollution prevention and control, and liability and compensation. Since FNPP deployment can raise quite politically and diplomatically sensitive issues, such as passage through designated sea lanes, port access approval, and sovereignty disputes over deployment waters, establishing cooperative and collaborative arrangements between countries through bilateral or regional agreements can help to address and resolve these sensitive issues. It may also be useful to establish effective mechanisms for the preparation, response, and cooperation of contracting parties, thereby enhancing the capabilities in jointly dealing with pollution incidents induced by FNPPs. Although there are no interstate agreements or international conventions specifically for FNPPs, there have been some specialized bilateral agreements and international conventions for nuclear ships, for example, the Brussels Nuclear Ship Convention, the 1964 USA-UK Agreement relating to the Use of United Kingdom Ports and Territorial Waters by the N.S. Savannah, and the 1968 Agreement between the Federal Republic of Germany and the Kingdom of Netherlands on the Use of Dutch Waters and Harbors by the NS Otto Hahn. These results can provide a reference for regulating FNPPs and their related marine environmental risks. Considering the special safety and environmental risks posed by FNPPs, a bilateral agreement can be concluded between the supplier state and the host state to determine relevant rights and obligations in terms of FNPPs’ navigation safety protection, pollution-prevention regulation, and nuclear damage liability and compensation [24]. Considering that the navigation of FNPPs may pass through the jurisdictional waters of a third country, similar agreements may also be negotiated between these states and the transit states to avoid disputes that could arise during FNPPs’ navigation from the supplier state to the deployment state [90].

A further way, an idealistic yet potentially more fundamental one, to resolve the convention application dilemma is for the international community to seek consensus on the legal status of FNPPs under maritime law and the law of the sea regimes. The legal status of FNPPs should be analyzed specifically in combination with the specific technology and specific situation adopted by FNPPs. UNCLOS does not define ships, but a summary of the definitions can be found in the London Convention, MARPOL, United Nations Convention on Conditions for Registration of Ships, and other conventions, confirming that navigational ability is the key element to defining ships. Whether FNPPs can be defined as ships depends on whether they have navigability. Considering the development of ship nuclear propulsion technology and the widespread practice of using nuclear propulsion icebreakers in the Arctic region [2,46,91], it is no longer a problem for FNPPs to have the autonomous navigational ability from a technological view. Moreover, if placed on barges, FNPPs may also be considered to have the navigational ability as a whole. Additionally, for “fixed or floating platforms” navigating in the marine environment, some conventions often include them in the definition of ships, such as the MARPOL 73/78, the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, and the Nairobi International Convention on the Removal of Wrecks. Therefore, FNPPs with autonomous navigational ability, FNPPs placed on moving barges, and FNPPs navigating in the ocean should all be considered as meeting the definition of ships. However, under current technologies, there is also a portion of FNPPs that lack autonomous navigational ability. Some are directly placed on the seabed, some are placed on floating dock-type reinforced concrete structures, and some are protected by breakwaters built around them [22,92]. These FNPPs are associated with fixed structures of a permanent nature and may not be considered able to meet the definition of ships. For these FNPPs with a fixed nature, it needs to be considered whether they could be defined as artificial islands or “artificial installations and structures”. UNCLOS has not made a clear definition of artificial islands. Legal academia generally considers that artificial islands need to meet several conditions, including non-natural formation, exposure of the water surface at high tide, and fixity on the seabed [41]. UNCLOS broadly defines “artificial installations and structures” as man-made “artificial installations and structures primarily used for the purposes of exploring or exploiting ocean resources (UNCLOS, 1982, Article 60). Some scholars have also pointed out that the Convention’s terminology on artificial installations and structures should be regarded as including artificial islands [93,94]. Therefore, if the design technology of FNPPs is to fix them on the seabed permanently, FNPPs may be considered artificial islands [16,22]. If the design of FNPPs uses non-permanent fixation technology, such as fixing them by breakwaters, FNPPs may be considered as artificial installations and structures. In summary, defining the legal status of FNPPs should be a combination of law and technology, with full consideration of the specific technologies and situation of FNPPs to determine their attributes together with a proper interpretation of the existing international maritime law and the law of the sea regimes.

5.2. Balancing FNPP Regulation and Freedom of Navigation

Coastal states’ deployment and regulation of FNPPs may create conflicts with freedom of navigation, “reflecting the ongoing contest between the freedom of navigation of maritime states and the regulation of coastal states” [95,96]. However, the existing international regulatory framework is inadequate in solving potential tensions. Therefore, relevant rules must be formulated to mitigate such tensions at the international level.

More specifically, these rules must address at least the following issues: Based on the existing marine zone delamination under the law of the sea, within what range of sea areas are states allowed to deploy FNPPs? Can FNPPs be deployed in the exclusive economic zones, in waters above the continental shelf, or on the high seas? If so, do FNPPs enjoy the freedom of navigation like ships? Should the special radioactive environmental risks of FNPPs be considered as constituting an inherent threat to the peace and good order of the coastal states and therefore empowers them the right to suspend innocent passage [41]? Or should FNPPs be treated as nuclear-powered ships and ships carrying nuclear substances, to which UNCLOS grants them the right of innocent passage on condition that they must comply with special requirements, including carrying documents, observing “special precautionary measures established for such ships by international agreements”, and confining passage to the sea lanes designated by the coastal states (UNCLOS, 1982, Articles 22, 23)? After the coastal states deploy FNPPs, are they allowed to establish safety zones around the FNPPs based on safety regulation and pollution prevention reasons? What are the “generally accepted international standards” or standards “recommended by the competent international organization” to clarify the breadth of safety zones around FNPPs? Only by establishing relevant rules to clarify these important issues can potential disputes and tensions be avoided.

5.3. Ensuring Prudent Marine Environmental Impact Assessment

Considering FNPPs’ pollution risks, the deployment of FNPPs should undergo prudent environmental impact assessment. In the Pulp Mills case, the International Court of Justice identified “the obligation to conduct environmental impact assessment as a requirement under general international law when industrial activity may have a significant adverse transboundary impact” [68]. UNCLOS has imposed the obligation of conducting marine environmental impact assessments on the states that plan to take activities with substantial marine environmental impacts. In this sense, deployment states have an obligation to ensure prudent marine environmental impact assessments before FNPP deployment [16]. However, as mentioned above, several insufficiencies remain in the environmental impact assessment stipulations under UNCLOS. Institutional improvements are, therefore, necessary to ensure the effective implementation of marine environmental impact assessments in practice.

To transform the general and rather vague obligation under UNCLOS into more concrete stipulations with effective implementation in practice, the “creation of a marine environmental impact assessment protocol for UNCLOS” can be considered as a viable choice, as recommended by Tanaka [75]. Such a protocol could “make assessment procedures operational from the initial stage of controversial projects”. The protocol could also provide the international adjudication bodies and an arbitral tribunal with “concrete guidelines and sufficient capacity to evaluate the adequacy of the marine environmental impact assessment” [75]. Furthermore, to ensure the effective implementation of marine environmental impact assessment before FNPPs are deployed, oversight from the IAEA would be critical. The IAEA should supervise the deployment state to ensure that the state fulfills its obligation of risk notification, monitor whether the notification is timely and whether it covers the necessary information that should be disclosed, supervise whether the deployment state promptly responds to the information fed back by the affected parties, and ensure the fairness and transparency of assessment procedures [97].

5.4. Improving Liability and Compensation Regimes

When FNPP-related marine pollution occurs, an effective liability and compensation mechanism is important for determining liabilities and providing remedies to victims. Unlike in the case of traditional land-based nuclear power plants, the manufacture, deployment, and operation of FNPPs involve multiple parties and countries. Consequently, the allocation of loss and liabilities is quite difficult. The several parallel and overlapping regimes concerning liability and compensation in place have created a significant fragmentation problem for FNPP-related pollution damage claims. The dilemmas posed by the different positioning of FNPPs and inconsistent principles and approaches for liability channeling have bordered the achievement of effective ex post remedies. In this context, relevant international organizations, such as the United Nations, IMO, and IAEA, should consider either drafting resolutions clarifying when FNPPs become subject to existing nuclear liability conventions or drafting a specialized convention to address the liability and compensation issues for FNPPs [6].

Nevertheless, it must also be recognized that regardless of which of the above approaches is adopted, the premise of drafting such international legal instruments is that “the international community first needs to seek a more unified framework for the basic principles and approaches in dealing with liability and compensation issues” [59]. Therefore, the international organization that leads the draft of such international legal instruments needs to address a series of highly disputable issues to ensure that the draft can gain broad international recognition and consensus, thereby avoiding future ratification deadlock. These thorny issues include clarifying whether the traditional liability channeling principle under nuclear liability conventions applies to the FNPP situation, determining how to allocate liabilities among the deployment state, supplier state, and flag state, ascertaining whether a collective compensation fund needs to be established, designating a proper legal forum for compensation claims and deciding a reasonable compensation cap when the limitation of liability is adopted in pollution damage.

6. Conclusions

In the context of the global energy transition toward carbon neutrality and the pursuit of more environmentally sustainable shipping [98,99], countries’ interests in nuclear energy are reawakened. Developing FNPPs to provide power supply for remote islands, offshore drilling platforms, and offshore exploration and development activities are becoming a feasible clean energy choice. Many countries have developed or are developing FNPPs. However, the deployment of FNPPs may pose challenges to the marine environment. The potential release of radioactive materials from FNPPs might have long-term consequences on the ocean, posing risks to the global community’s environmental interests in ocean governance [100,101]. An effective international regulatory framework with safety regulations, pollution control mechanisms, regular inspections, prudent environmental impact assessment, cooperative emergency response plans, prompt relief, and adequate compensation is essential in addressing FNPPs’ marine environmental challenges, securing the international community’s environmental interests in ocean governance. However, the existing international regulatory framework has several shortcomings and insufficiencies that may hinder its ability to effectively address relevant challenges. It, therefore, calls for relevant reforms and innovations to promote the formulation of a more effective international regulatory framework. Some potential solutions, such as reaching an international consensus on the legal classification of FNPPs, expanding the scope of existing nuclear conventions to include FNPPs, creating specialized bilateral or regional agreements, and improving marine environmental impact assessment, liability, and compensation regimes, may help to address the shortcomings of the existing regulatory framework for FNPPs and their related marine pollution issues. We hope that this research could provide some insights for future studies on regulating FNPPs, preventing their radioactive marine pollution risks, and developing a more effective regulatory framework to facilitate the development, deployment, safe operation, and pollution control of FNPPs.