ASN-IRSN Merger: Constitutional Council Confirms Constitutionality of Nuclear Safety Reform

On Friday, May 17, the Constitutional Council rejected an appeal by parliamentarians from the Nupes and Liot groups who opposed the merger between the French Nuclear Safety Authority (ASN) and the Institute for Radioprotection and Nuclear Safety (IRSN). The merger is therefore set to proceed and is expected to be completed in 2025.

Initiated during the Nuclear Policy Council (CPN) in February 2023, the nuclear safety bill was adopted in April 2024 by a large majority of the National Assembly and Senate members. It plans for the creation of the Nuclear Safety and Radioprotection Authority (ASNR) in 2025, merging ASN and IRSN.

Following this vote, left-wing (Nupes) and independent (Liot) parliamentarians appealed to the Constitutional Council, arguing the risk of losing the independence of experts and fearing decision-making opacity. They particularly criticized the challenge to the “dual system” organization currently in place, which separates expertise from decision-making in the existing system. The complainants also criticized the Parliament for leaving the definition of several organizational modalities to the internal regulations, believing this undermined the legislature’s authority.

These arguments did not persuade the Constitutional Council, which ruled that the law does not alter the “obligations to which civil nuclear activities are subject.” Moreover, the council found that the reform measures maintain a distinction between expertise and decision-making. Complaints related to organizational aspects in the internal regulations were also dismissed.

Upcoming Steps

The law provides for the merger of ASN and IRSN on January 1, 2025, with several transitional steps following enactment. The current members of the Nuclear Safety Authority will continue their terms until their expiration.

The text stipulates that the ASNR will replace the IRSN, except for certain missions transferred to the CEA (French Alternative Energies and Atomic Energy Commission). In July 2024, the government must submit a report to Parliament on the necessary resources for the year 2025 and evaluate the possibility of appointing a “prefigurator” for the new entity, tasked with anticipating the organizational structure of the future organization. Finally, the accompanying organic law project provides that the Head of State will designate the president of the future authority after consultation with the relevant parliamentary committees. ■