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Published on 28 June 2016

The CEA is strongly committed to ensuring the highest levels of nuclear safety, whether as an operator of nuclear facilities or as a research organisation. The studies it leads in the field are not only backing by IRSN, but also French (EDF, Areva) and foreign nuclear operators. These studies fall within a long-term approach of continuous progress. It is worth distinguishing between R&D on current Generation II and III reactors, and research devoted to Generation IV reactors for which nuclear safety is a major priority.
Though the Fukushima accident did not reveal the existence of any new phenomena that needed investigating, it did highlight a number of key priorities and the need to maintain R&D efforts over time by relying on the available experimental facilities.

​General framework for nuclear safety research

The research programmes at the CEA cover two key areas:

  • Behaviour of structures during an earthquake
  • Behaviour of reactors in the event of a severe accident.

These programmes rely on the simulation of the physical phenomena involved and on the comparison of these simulations with the experimental results obtained in CEA's facilities, e.g.: shaking tables on the Tamaris platform to study the behaviour of structures under earthquake conditions, Mistra to study hydrogen risks, Plinius to study concrete-corium interactions, and Verdon to study fission product releases.

Safety of 2nd and 3rd
generation reactors

Research in this field can be divided into three main topics, each corresponding to a successive phase of an accident scenario:

  • Hydrogen risks, which are specific to water reactors and can result in the degradation of the reactor containment
  • Release and transport of fission products, which consists in analysing the risks of radioactive releases under accident conditions
  • Behaviour of corium, where the molten reactor core becomes a highly radioactive magma that can melt through concrete. Corium interactions with the reactor's containment barriers are studied to prevent the corium from coming into contact with the environment.

R&D at the CEA is exploited by both nuclear operators and IRSN in particular within the scope of regulatory safety reviews.

Safety of 4th
generation reactors

Research carried out at the CEA within the scope of the Generation IV international forum (GIF) is particularly focusing on sodium-cooled fast reactors (SFRs) via the Astrid integrated technology demonstrator.

Sodium-cooled fast reactors have a number of inherent safety advantages when it comes to reactor cooling: significant thermal inertia and diversified heat sinks (water, but also atmosphere and natural convection).

Astrid and Generation IV SFRs in general must comply with the highest level of safety requirements, in particular by taking into account feedback from the Fukushima stress tests. Several technology breakthroughs have been developed by the CEA teams: the development of a new reactor core concept with optimised safety features, the elimination of sodium interactions' possibilities with air or water (risk of chemical reactions) and the development of a corium core catcher.