The protection of the environment in the nuclear sector is one of the primary aims both of nuclear law and of environmental law. Both branches of law do apply to nuclear activities, but they are not only different in nature, but they have also developed differently.
Nuclear law is a branch of law that is not only older than environmental law, it also contains much more detailed and complex rules of a technical nature. This is of course not surprising since nuclear energy legislation applies to a highly technical field of the economy, with some activities and materials posing unusual risks to human health, safety and the environment, as well as national and international security risks. It applies to a variety of technical fields, from nuclear power generation to the use of radioactive sources in hospitals, industry and agriculture.
Safety is the principal requisite for the use of nuclear energy and the applications of ionizing radiation and nuclear law therefore essentially aim at preventing nuclear accidents that may cause harm to individuals, society and the environment. The primary objective of nuclear law is broader than the one of environmental law. Unlike environmental law, it also takes into account the protection of individuals and property: "To provide a legal framework for conducting activities related to nuclear energy and ionizing radiation in a manner which adequately protects individuals, property and the environment [3]." Core nuclear law conventions such as the IAEA Nuclear Safety Convention (1994) [4] and the IAEA Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management (1997) [5] aim at reaching a higher level of safety worldwide, including preventing the occurrence of nuclear accidents that would negatively impact people, property and the environment.
Environmental law is a branch of law that was developed later than nuclear law and that, unlike nuclear law, is not specific to one type of industry. The primary objective of environmental law is focused exclusively on the protection of the environment: "To provide substantive, procedural and institutional rules […] that have as their primary objective the protection of the environment [8]." After a number of industrial accidents in the second half of the twentieth century that had devastating consequences for the environment, governments and lawmakers realized that there was an urgent need to take action. Environmental law entered the gates of international law through the 1972 Stockholm ("Stockholm Declaration") and the 1992 Rio de Janeiro ("Rio Declaration") Declarations of the United Nations Conference on the Environment [9]. Both declarations constitute major milestones for recognizing explicitly the right to a healthy environment and to affirm the need to protect, preserve and improve the state of the environment and to ensure sustainable and environmentally sound development. They were an attempt at forging a basic common outlook on how to address the challenge of preserving and enhancing the human environment.
One of the most relevant principles of the Stockholm Declaration for nuclear activities is embodied in its Principle 21 which provides in its first part that States have, in accordance with
the Charter of the United Nations and the principles of international law, the sovereign right to exploit their own resources pursuant to their own environmental policies. It acknowledges that States with uranium mines, oil reserves or gas wells on their national territory have the right to use these resources for their economic benefit. However, if these States decide to do so, they must respect the second part of Principle 21 which relates to the prevention of environmental harm. The second part of Principle 21 stresses that States also have the responsibility to ensure that activities within their jurisdiction or control do not cause damage to the environment of other States or of areas beyond the limits of national jurisdiction. This part is particularly important for nuclear activities, as evidenced by the 1986 Chernobyl accident that had an impact on the environment in a multitude of States. Immediately after this nuclear accident two international nuclear law conventions were adopted under the auspices of the Agency that aimed at mitigating environmental damage. The Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency (1986) and the Convention on Early Notification of a Nuclear Accident (1986) requiring States to cooperate and facilitate prompt assistance and support in the event of nuclear accidents or radiological emergencies and to report the accident's time, location, nature, and other data essential for assessing the situation are strong illustrations of Principle 21 of the Stockholm Declaration. In its Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons [10], and later in the Pulp Mills on the River Uruguay case [11], the International Court of Justice considered the obligation not to cause damage to the environment of other States to constitute a rule of international customary law.
The Rio Declaration very much resembles the Stockholm Declaration but makes an explicit reference to some of the most fundamental principles of environmental law such as the precautionary principle ("In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation") [12] and the polluter pays principle ("National authorities should endeavour to promote the internalization of environmental costs and the use of economic instruments, taking into account the approach that the polluter should, in principle, bear the cost of pollution, with due regard to the public interest and without distorting international trade and investment") [13]. Both the precautionary principle and the polluter pays principle play indeed a very significant role in the nuclear field.
The precautionary principle is most visible in the optimization of protection against radioactive emissions as illustrated by the term ALARA ("as low as reasonably achievable, economic and social factors being taken into account"), as required by the International Commission on Radiological Protection (ICRP), which indicates that the purpose of radiation protection is to ensure that the hazards from radiation are kept low. The polluter pays principle has been at the heart of the development of international nuclear third party liability legislation which in essence holds the operator of a nuclear installation ("the polluter") liable for the damage that is caused by a nuclear accident. The first 'generation' of international nuclear third party liability conventions, including the Vienna Convention on Civil Liability for Nuclear Damage that was concluded under the auspices of the Agency (1963) [14] and the Paris Convention on Nuclear Third Party Liability that was concluded under the auspices of the OECD (1960) [15], focus on property damage and personal injury. Neither of the first generation conventions contained a specific or explicit reference to environmental damage but this did not mean that environmental damage could not be compensated as property damage or otherwise. After the 1986 Chernobyl accident lawmakers realized that international nuclear third party liability legislation needed to be reformed, in particular to increase the liability amounts. The polluter pays principle was maintained in the second 'generation' of international nuclear third party liability conventions, including the Protocol to amend the Vienna Convention on Civil Liability for Nuclear Damage (1997) [16] and the Protocol to amend the Paris Convention on Nuclear Third Party Liability
(2004) [17], but amendments were made to ensure compensation for environmental damage subject to a range of qualifying elements to determine to what extent costs shall be compensated. Costs of measures to reinstate significantly impaired environment, loss of income from an economic interest in the use of the environment and costs of measures to prevent nuclear damage as defined have become compensable to some extent [18]. The polluter pays principle is also widely applied when funding costs for decommissioning nuclear power facilities and when managing radioactive waste. This may be illustrated by legislation in the European Union where Article 37 of the Euratom Treaty obliges each European Union Member State to provide the European Commission with such general data relating to any plan for the disposal of radioactive waste in whatever form will make it possible to determine whether the implementation of such plan is liable to result in the radioactive contamination of the water, soil or airspace of another EU Member State [19].
But the Rio Declaration also goes further than the Stockholm Declaration by supporting the development of procedural techniques to protect the environment including most notably the obligation to conduct environmental impact assessments. The obligation to organize environmental impact assessments also applies for nuclear installations and was later reproduced in the IAEA Convention on Nuclear Safety:
“Each Contracting Party shall take the appropriate steps to ensure that appropriate procedures are established and implemented: […] for consulting Contracting Parties in the vicinity of a proposed nuclear installation, insofar as they are likely to be affected by that installation and, upon request providing the necessary information to such Contracting Parties, in order to enable them to evaluate and make their own assessment of the likely safety impact on their own territory of the nuclear installation [20].”
Another procedural technique is the obligation to notify and provide information to other States of emergencies that are likely to produce effects on the environment of other States and the obligation to consult with these States at an early stage and in good faith. The obligation to notify other States of harmful events that have taken place on national territory had already explicitly been integrated in international nuclear law as a result of the 1986 Chernobyl accident with the adoption of the abovementioned IAEA Convention on Assistance in the Case of a Nuclear Accident or a Radiological Emergency (1986) and the IAEA Convention on Early Notification of a Nuclear Accident (1986).
Since the adoption of the Stockholm and Rio Declarations international and national environmental law have further developed with the objective to limit activities that are harmful for the environment and to ensure remediation of environmental damage. Several international environmental law conventions do apply to nuclear activities as illustrated for example by the London Dumping Convention (1972 and 1996) which prohibits the dumping of radioactive waste at sea [21], the United Nations Convention on the Law of the Sea (UNCLOS, 1982) which obliges its contracting parties to minimize to the fullest possible extent the release of toxic, harmful or noxious substances, especially those which are persistent such as nuclear substances [22] and the Convention for the Protection of the Marine Environment for the North-East Atlantic (OSPAR, 1992) which imposes an obligation on contracting parties to take all possible steps to prevent and eliminate pollution to the maritime area, including radioactive substances and waste [23]. In developing their respective national programs for the peaceful uses of nuclear energy and ionizing radiation, national legislators will therefore bear in mind the importance of protecting the environment.
A very effective way to ensure environmental protection in the nuclear field has proven to be public access to information and involvement of stakeholders in nuclear decision-making. Since the soil, the air, the water and the biodiversity are not owned by anyone individually but are considered to belong to all of us, one of the principal tools of environmental law is to ensure transparency of environmental information and to involve various stakeholder in the decision-making of industrial projects, including not only the public who is affected or likely to be affected by the environmental consequences of these projects, but also non-governmental organizations that aim at preserving the state of the environment. In the nuclear area this objective of environmental law has been implemented in various ways such as, for example, by actively informing the public and other stakeholders on the risks of nuclear activities and the impact of radioactive emissions on human health and the environment, by allowing stakeholders to get involved in decision-making regarding nuclear licensing, by involving the public when assessing the environmental impact of new nuclear installations and by concluding long-term partnership agreements with local communities for hosting radioactive waste facilities and repositories. Several States with nuclear installations have made a giant step between the early days of nuclear development and now in terms of participation of stakeholders in nuclear decision-making. Whereas in the 1960s and 1970s most governments adhered to a "decide, announce and defend" model to build and operate nuclear installations whereby there was hardly any possibility for stakeholders other than the operator, the regulator and the government to have a say, many governments have now substantially moved to a model of "engage, interact and cooperate" [24]. In the broadest sense, “stakeholders” now include the public, businesses and corporations, economic actors, representatives from non-governmental organizations, local, regional and national public authorities and nuclear regulators. Two conventions in the environmental law domain have served as a source of inspiration on transparency of information and stakeholder involvement for States worldwide [25].
Under the United Nations Economic Commission for Europe Convention on Access to Information, Public Participation in Decision-Making and Access to Justice in Environmental Matters ("Aarhus Convention", 1998) contracting parties are required to make the necessary provisions so that public authorities (at national, regional or local level) will contribute to these rights to become effective, including the right of the public to access environmental information, the right of the public to participate in environmental decision-making and the right the public to accede to court. The right of access to environmental information includes the right to receive environmental information that is held by public authorities [26]. This may include information on the state of the environment prior to the construction of a new radioactive waste repository or a nuclear power plant or a nuclear research reactor, but also on policies or measures taken, or on the state of human health and safety where this can be affected by the state of the environment. In addition, public authorities are obliged to actively disseminate environmental information in their possession such as, for example, on the impact of the discharging of a nuclear power plant's cooling water on the temperature of the nearby river or sea. The Aarhus Convention also foresees the right to participate in environmental decision-making including making arrangements by public authorities to enable the public affected and environmental non-governmental organizations to comment on, for example, proposals for new nuclear installations affecting the environment, or plans and programmes relating to the environment, these comments to be taken into due account in nuclear decision-making, and information to be provided on the final decisions and the reasons for it. Finally, the Aarhus Convention also contains the right to challenge decisions by public authorities that have been made without respecting the two aforementioned rights or environmental law in general before a court.
The United Nations Economic Commission for Europe Convention on Environmental Impact Assessment in a Transboundary Context ("Espoo Convention", 1991) imposes obligations on contracting parties to assess the environmental impact of certain activities at an early stage of planning, including nuclear activities [27]. It lays down the general obligation of contracting parties to notify and consult each other, as well as the public in these contracting parties, on all major projects for individual installations under consideration that are likely to have a significant adverse environmental impact across boundaries. Such notification of and consultation with other contracting parties is done on the basis of environmental impact assessments whereby the environmental effects of a particular facility or plan are analysed and recorded in a report together with corrective measures to limit the negative effects. The comments of these contracting parties and their public must be taken into account prior to licensing the facility. The Espoo Convention is particularly important for nuclear activities for two reasons. Firstly, because the entire nuclear sector and all fuel-cycle facilities are based on a regulatory model of licensing and authorisations. The IAEA Convention on Nuclear Safety mentions that:
"The legislative and regulatory framework shall provide for: […] (ii) a system of licensing with regard to nuclear installations and the prohibition of the operation of a nuclear installation without a licence" [28].
The Espoo Convention obliges contracting parties to ensure that environmental impact assessments are organised and that transboundary consultations take place prior to granting specific licenses in the nuclear field. Secondly because a substantial number of nuclear facilities has been built near borders with neighbouring States and because nuclear accidents cause radiological emissions and environmental effects that may go far beyond national borders. The Espoo Convention obliges States to notify and consult with other States prior to licensing nuclear facilities that may affect the environment of these other States either as a result of normal operation or as a result of an accident. In this regard it is also worth mentioning that in 2017 good practice recommendations on the application of the Espoo Convention to nuclear energy activities have been published [29].
A decade after the adoption of the Espoo Convention several States decided to extend the idea of conducting environmental assessments, transboundary consultations and public participation beyond the level of individual installations and to apply it to certain governmental plans, programmes and policies which are likely to have significant environmental effects. The Protocol on Strategic Environmental Assessments ("Kiev Protocol", 2003) covers plans, programmes and policies that set the framework for future consent of individual installations [30]. A strategic environmental assessment is the evaluation of the likely environmental, including health, effects which comprises the determination of the scope of an environmental report and its preparation, the carrying out of public participation and consultations, and the taking into account of the environmental report and the results of the public participation and consultations in a plan or programme. A specific illustration of the application of the Kiev Protocol to the nuclear field is, for example, a governmental plan for selecting a particular method for the long term management of low, intermediate or high level radioactive waste or a governmental program on whether or not nuclear should be part of the national energy fuel mix to secure electricity supply in the future [31].