London – The United Kingdom has formally joined the Convention on Supplementary Compensation for Nuclear Damage (CSC), marking a key milestone in the international effort to enhance nuclear safety, accountability, and environmental protection. The UK deposited its instrument of accession on October 3, 2025, becoming the 12th Contracting Party to the CSC. The convention will take effect for the UK on January 1, 2026.
The CSC, established under the International Atomic Energy Agency (IAEA), provides a common legal framework to ensure prompt and adequate compensation for damage caused by nuclear incidents, covering harm to people, property, and the environment. The UK participation bridges existing regional frameworks under the Paris and Vienna Conventions, advancing efforts toward a single, unified global nuclear liability system.
IAEA Director General Rafael Mariano Grossi called the UK’s move “a historic step” that connects the Paris and Vienna regimes for the first time. He said it brings the world closer to a universal nuclear liability framework, ensuring fairness and financial protection across borders.
The CSC also establishes a supplementary international fund to provide additional compensation beyond national levels in the event of a nuclear accident. Supported by contributions from all member states, this fund ensures broader coverage and international cooperation during emergencies.
With the UK membership, the CSC will cover around 190 nuclear reactors nearly 45% of the world’s operational total expanding its global reach significantly. The UK’s accession is the first by a Paris Convention member, setting an example for other European nations to join.
For over a decade, the IAEA has urged countries to join nuclear liability agreements to create a unified global safety and compensation system. The UK’s entry fulfills a long-standing goal, reinforcing international cooperation on nuclear responsibility.
Beyond legal and safety benefits, the move highlights the UK’s commitment to clean energy and climate goals. By strengthening confidence in nuclear governance, it aims to support the growth of low-carbon energy technologies, such as Small Modular Reactors and fusion research.
The UK’s accession marks an important step toward safer and more sustainable nuclear energy development ensuring swift and fair compensation in case of accidents while reinforcing global trust in nuclear power as a climate-friendly energy source.