CYIL vol. 16 (2025)

VLADIMÍR SHARP, GABRIELA BLAHOUDKOVÁ financial liability. However, such limitations are subject to a minimum threshold set by the Convention itself. Specifically, liability cannot be limited to less than the equivalent of 5 million US dollars per nuclear incident. 32 This interpretation effectively brings SMRs under the scope of the Vienna Convention, even in cases where the associated risk is demonstrably lower. The exclusion clause for mobile reactors (sea or air-based) was not intended to reflect a reduced risk, but rather to address the jurisdictional complexities of mobile nuclear units operating across state boundaries. As such, the Convention offers no mechanism to exclude low-risk reactors, such as SMRs mounted on stationary terrestrial platforms, from its application. Efforts to modernize the Vienna framework have led to the adoption of the Protocol to Amend the Vienna Convention (1997), which establishes the Amended Vienna Convention. This revised instrument retains the core principles of strict and exclusive operator liability but introduces two mechanisms that may prove essential for the future regulation of SMRs: • Graduated liability limits: contracting parties can adjust the operator’s liability based on the specific nature of the nuclear installation or the nuclear substances involved, as well as the potential consequences of an incident. This mechanism permits the establishment of a lower financial cap than otherwise stipulated by the protocol, provided that it does not fall below 5 million SDRs. 33,34 • Exclusion mechanism: Under conditions to be defined by the International Atomic Energy Agency (IAEA), Parties may exclude certain types of nuclear installations from the Convention’s application, should their risk profile warrant such an exemption. 35 However, these mechanisms remain largely untested. The IAEA has not yet adopted specific criteria for excluding SMRs or other types of installations, and the number of contracting parties to the Amended Vienna Convention remains relatively limited. In the case of the Czech Republic, although it is a signatory to the Amended Convention, it has not yet ratified it, which currently limits its legal flexibility in addressing SMR-specific liability issues. In conclusion, it is questionable whether the current framework established by the original Vienna Convention may or may not present a regulatory barrier to the broader deployment of SMRs, due to its rigid liability provisions. Ratification of the Amended Vienna Convention, or alternatively, the development of a tailored liability regime, could certainly offer a viable legal path forward, aligning liability principles more closely with technological innovation and proportional risk assessment. 36 Under the current framework of the Vienna Convention on Civil Liability for Nuclear Damage, there is no provision allowing for the exclusion or differentiated treatment of nuclear material used in SMRs. Despite the long 32 The Convention uses a special unit of account tied to the value of the US dollar based on its gold parity as of 29 April 1963—equivalent to 35 US dollars per troy ounce of fine gold—resulting in a “floating” limit that reflects this historical valuation rather than current currency rates. See Vienna Convention, Article V(3). 33 SDR is an international reserve asset created by the International Monetary Fund. 34 Vienna Convention as amended by the Protocol, Article V(2). See the document including the explanatory text here https://www-pub.iaea.org/MTCD/Publications/PDF/Pub1279_web.pdf [accessed 30 June 2025]. 35 Vienna Convention as amended by the Protocol, Article I(2). 36 See HANDRLICA, J. and NOVOTNÁ, M., ‘The Feast of Insignificance of Small Modular Reactors in International Nuclear Law’ in Czech Yearbook of Public and Private International Law (Czech Society of International Law, Prague 2021) pp. 326–336.

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