Common approach for the safety of new reactors and nuclear safety in Ukraine, these are the topics discussed by WENRA in Paris

Update of the situation of nuclear plants in Ukraine, new strategic objectives that will outline WENRA's activities in the coming years and definition of safety levels for the new technologies represented by the emerging so-called Small Modular Reactor and Micro Reactor plants: these are the main topics addressed, on 14 and 15 November 2023, during the plenary meeting of WENRA (Western European Nuclear Regulators Association), the Association made up of the Directors responsible for the nuclear safety authorities of the Member States of the European Union. Switzerland, Ukraine and Great Britain are also full members.

WENRA aims to develop a common approach to nuclear safety, as a basis for its regulation within the EU and promotes its continuous improvement, guaranteeing the European institutions an independent evaluation capacity.

Over time, the Association has been opened to other States as Observatories (Canada, United States, Japan and Armenia). ISIN has participated in the Association since its establishment in 1999.

WENRA has developed considerable harmonization work which, starting from 2006, has led to the definition of a set of reference criteria for the safety of reactors in operation, the treatment, storage and disposal of radioactive waste and irradiated fuel as well as the decommissioning of the plants, subject to implementation by the Member States.

During the meeting, the Director of the Ukrainian Nuclear Safety Authority, the SNRIU, reported on the state of the Zaporizhzhya power plant and the impossibility of taking action to ensure nuclear safety. The situation of the water reserves for the refrigeration of the reactors was also described which, although stopped, always need the nuclear fuel inside them to be refrigerated. The loss of the Nova Kakhovka dam, downstream of the power plant area, led to a drastic reduction in the water reserves surrounding the power plant. However, the set of wells built to supply the systems' refrigeration basins as well as the approach of the winter season allow us to estimate a very prolonged autonomy.

With reference to the specific themes of the Association, the heart of the meeting was represented by the definition, approved by the directors of the nuclear safety authorities, of the new terms of reference for WENRA's action, and of the new strategic objectives that will outline the activities of the Association.Their definition was inspired by the current context of growing concern for a correct balance of the growth in energy demand and its consumption and by the nuclear industry's commitment to new and innovative technological solutions as well as by the prevailing geopolitical context and the consequent growing support for the issue of nuclear energy which is seen in many countries. In this context, the strategy of WENRA action is represented by the continuation of the search for common safety requirements on the main issues to be applied by each member, by the adoption of the practice of regulatory cooperation, in particular for review and evaluation of new technologies, from the commitment to seek a common position on the problems that will be addressed.

The new terms of reference will be signed by the Directors of all WENRA member nuclear safety authorities.

Also in this plenary, the topic of defining safety levels for the new technologies represented by the emerging so-called Small Modular Reactor and Micro Reactor plants was discussed. Although for these we can hypothesize greater safety in terms of a radiological inventory, lower installed power, passive heat removal systems, low power density of the fuel, lower radioactive releases even in the case of severe accidents, their widespread use on the territory (present where there is a demand for energy) requires safety requirements that can guarantee the non-necessity of providing evacuation zones for the population around the plant, even in the event of serious accidents. The review of the current safety objectives applicable to these new technologies therefore continues.

During the meeting it was decided that from 2024 the Presidency of WENRA will pass from the French Nuclear Safety Authority (ASN) to the Great Britain Nuclear Safety Authority (ONR).