STUK assesses the safety of small nuclear power plants together with the French and Czech authorities

Finland is currently in the process of renewing its nuclear energy legislation and the complementary regulations and guidelines issued by STUK. One of the objectives of this work is to streamline the licencing of new nuclear power plant types. The work carried out with the French and Czech authorities provided valuable information on the suitability of the current regulations and guidelines for assessing the safety of small nuclear reactors. Finland's current rules have been drawn up mainly for large electricity-producing reactors, and for that reason some of the requirements are not applicable to smaller reactors.

The French and Czech authorities that participated in the assessment have regulations and guidelines that are very similar to the Finnish ones and both countries also aim to develop their legislation to better take into account the specific characteristics of SMRs. For example, the International Atomic Energy Agency (IAEA) has considered how assessments made by the nuclear safety authorities of different countries on the safety of nuclear power plants could be used in other countries' licencing processes.

Eero Virtanen, Principal Advisor for STUK, who was responsible for the assessment project, says that the work provided experience on assessments carried out jointly by various authorities, as well as an opportunity to learn more about one type of SMR plant. Although the objective was not to harmonize the requirements used in different countries, the work still aimed to help plant designers in finding solutions that would be acceptable in several countries.

All authorities involved in the assessment used their existing national legislation as a starting point. “All participants got a good idea of the regulations and guidelines of the participating countries, background to the requirements and the licencing procedures", says Eero Virtanen.

The assessment was carried out on the NUWARD SMR plant developed by the French energy company EdF. EdF is planning to build nuclear power plants based on this reactor type in France and submitted for evaluation the documentation it has prepared for the pre-licencing process in France. The assessed topics included safety design requirements, initiating events used as design basis, the use of passive systems in safety functions, and the development of software used in safety analyses.

There are on-going discussions about continuing the preliminary assessment of the NUWARD SMR facility with new topics. Other countries’ radiation and nuclear safety authorities interest in participating in the assessment is also being surveyed.