2026

A delegation from the Spanish Nuclear Safety Council, led by Commissioner Francisco Castejón and comprising a team of the regulatory body’s technical experts, participated this week in the working sessions of the Committee on the Safety of Nuclear Installations (CSNI) of the Nuclear Energy Agency (NEA) held in Paris, France.

This meeting purpose is to review the progress and planning of mandated activities, as well as to approve working group mandates, new projects, and technical reports. These sessions aim to maintain an up-to-date programme of work defined around the interests and needs of the standing committee members, paying specific attention to prioritising CSNI activities for the upcoming 2027–2028 period.

Working Groups

During the sessions, various reports and proposals prepared by the CSNI working groups were presented for review and approval. In the field of risk assessment, the Working Group on Risk Assessment (WGRISK) proposed a technical document on dynamic probabilistic safety assessments (dynamic PSA), along with a follow-up activity to further develop this methodology. Additionally, it presented a final report comparing different approaches to analysing the effects of accidents involving radiological releases to the environment.

The Working Group on Integrity and Ageing of Components and Structures (WGIAGE), focused on structural integrity and component ageing, submitted several initiatives for approval. Notable among these were studies evaluating how uncertainties influence probabilistic structural assessments, as well as civil work damage state criteria under seismic events and their consistency with equipment supporting requirements. This group also presented several technical reports, including those related to the ageing management of key elements (such as containment liners and spent fuel pools), the results of an international benchmark exercise on "leak-before-break", and a summary report on pipe integrity.

Regarding human and organisational factors, the Working Group on Human and Organisational Factors (WGHOF) presented a report focused on ensuring safety during periods of prolonged disruption, drawing on lessons learnt from the COVID-19 pandemic. Furthermore, it addressed a specific analysis of the organisational challenges associated with Small Modular Reactors (SMRs), identifying the main difficulties, research needs, and potential methodological approaches for their safe implementation.

Joint Projects and Other Topics

The meeting also addressed the activities of the CSNI Programme Review Group (PRG) and reviewed the status and progress of the NEA Joint Nuclear Safety Research Projects. Among these, projects currently under consideration were evaluated, alongside the status of the Halden HTO project and technical progress within the framework of the PRIME experimental project and the ATHENA collaborative framework.

The second day covered topics of future interest, such as activities related to Artificial Intelligence (AI) and updates on the NEA workshop focused on the obsolescence of Instrumentation and Control (I&C) systems and the ageing of electrical cables, developed as part of the activities of the VVER reactors engineering fund. This planning effort includes key contributions to establishing the necessary scientific priorities to ensure the safety of existing installations, as well as driving new methodological frameworks developed by the Safety Assessment of Nuclear Designs (SAND) institute.

Coordination with other international institutions, such as the European Commission and the International Atomic Energy Agency (IAEA), was also discussed during these sessions. Both organisations presented their recent activity reports to optimise the implementation of good practices and lessons learnt, with the additional participation of several industry representatives.

The CSN maintained a prominent role in the Committee's technical sessions, taking part in discussions and in the review of the main reports and proposals submitted by the working groups in core areas such as risk assessment, structural integrity, and human and organisational factors.

Regulatory Activities Update

Within the framework of close coordination between the Agency's bodies, the meeting featured presentations from the heads of the NEA Division of Nuclear Installation Safety (SAF) and the Division of Radiological Protection and Human Aspects of Nuclear Safety (RP-HANS), who detailed the status of technical publications and ongoing activities. Similarly, the activity report of the Committee on Nuclear Regulatory Activities (CNRA) was presented, along with the latest updates from its Working Group on New Technologies (WGNT).

These exchanges enable the evaluation of shared strategic approaches in response to the entry of new actors into the industry, regulatory adaptation for the oversight of new reactors, and the licensing of emerging technologies. This ensures that the scientific developments of the CSNI directly support the inspection and regulatory control practices of oversight bodies.

Committee on the Safety of Nuclear Installations

The mission of the Committee on the Safety of Nuclear Facilities (CSNI) is to assist the NEA Member States in maintaining and developing the scientific and technical knowledge base necessary to assess the safety of nuclear power plants and fuel cycle facilities on an ongoing basis. The CSNI is made up of experienced scientists and engineers with responsibilities for nuclear safety and related research programs, as well as representatives of the regulatory authorities. To carry out its work, the Committee relies on several specialised working groups addressing different domains of nuclear safety.

The CSN participates in the main committee as well as in numerous associated working groups and projects, contributing to the analysis and management of accidents, risk assessment, the integrity and ageing of structural components, human and organisational factors, as well as the study of external events and fuel safety. Its involvement also spans the analysis of new technologies and the application of lessons learnt from operational experience, such as the Fukushima accident, within a framework of international cooperation.

The Spanish regulator considers it important to maintain active participation in all of them, as their results are essential for the advancement of technical knowledge that will be incorporated into the regulation.