The NEA's working party on nuclear criticality safety. Tackling global challenges through international cooperation

Criticality-safety, like much of the nuclear industry, is under pressure to continuously optimise its practices to achieve holistic safety in all facets of energy production, while operating within a context of increased regulatory and societal expectations, among other drivers. International co-operation, as undertaken within the auspices of the OECD's Nuclear Energy Agency, has proven invaluable to member countries by effectively leveraging scarce experimental facilities, consolidating the collected knowledge of experts, and sharing the lessons learned within its members' collective experience. The Working Party on Nuclear Criticality Safety (WPNCS) and its members have been a global leader serving the international community for more than 25 years, in its capacity of forum of reference for criticality safety experts among countries, which represent approximately 85 percent of global nuclear energy production. This paper presents a review of the historical background leading to the creation of the working party, its governance and how it has evolved over its 25 years of operation. A review of major achievements since the last review paper in 2019 is provided, and new activities that are further presented as stand-alone papers at this conference are briefly listed. Finally, challenges on the horizon in criticality safety and perspectives for the WPNCS are addressed. (author)