With a power of less than 300 MWe, SMRs are characterized by a design that is simpler than high power reactors currently in service. The diversity of the nearly 70 concepts proposed around the world calls for harmonization of safety requirements in force in countries wishing to develop such reactors. In France, EDF is developing a PWR reactor concept called NUWARD, intended for export.

In its information note, the Institute states that most of these concepts have not progressed past the detailed preliminary design stage. Because of their low power and small size, SMRs offer a variety of design choices, some of which can improve safety. A review of the available information tends toward showing that SMRs should be able to meet more stringent safety objectives than high power reactors in terms of limiting releases in normal and accident situations–including serious accidents–and the frequency of core melt.

These different concepts must therefore be examined in detail in order to be able to take a position as to the level of safety that can be achieved with this type of reactor. In this regard, identification of the inherent safety features of these reactors–particularly those based on passive safety systems–will require a thorough understanding of the physical phenomena involved.

Beyond several years of participation in the IAEA SMR Regulators’Forum, IRSN intends to develop its actions on this subject, specifically by implementingof dedicated studies and research.