Proposal of new safety measures for European Sodium Fast Reactor to be evaluated in framework of Horizon-2020 ESFR-SMART project

Following the previous European projects EFR and CP ESFR, a new Horizon-2020 project, called ESFR-SMART, was launched in September 2017. This project will consider the safety objectives envisaged for Generation-IV reactors and the update of European and international safety frameworks, taking into account the Fukushima accident. In accordance with these objectives, guidelines will be defined to drive ESFR-SMART developments, mainly simplifying the design and using all the positive features of the Sodium Fast Reactors (SFR), such as low coolant pressure; efficiency of natural convection; possibility of decay heat removal (DHR) by atmospheric air; high thermal inertia and long grace period before a human intervention is needed. In this paper, the safety objectives are presented in terms of defence-in-depth principle, extreme natural hazards to take into account, mitigation measures, etc. In this R&D framework, a set of new ambitious safety measures is introduced for further evaluation within the ESFR-SMART project. This proposed set aims at consistency with the main lines of safety evolutions since the Fukushima accident, but it does not yet constitute the final comprehensive safety analysis. This analysis will be done in the ESFR-SMART project to assess the relevance of the whole design in comparison to the final safety objectives. It should also be noted that some of these proposals are useful but could be replaced by other proposals in case of non-final validation. This first reassembly leads to a simplified reactor, forgiving and including a lot of passivity. This first version will be reinforced by the various tasks works in the forthcoming months.