Fundamental Research Division
The DRF at the CEA assemble approximately 6,000 scientists since January 2016.
Scientific result | Radioactive waste
The conditioning of highly active and long-lived nuclear waste should include several barriers to isolate radionuclides from the environment, during the required storage time. One of these barriers is a steel outer container that will corrode extremely slowly over several thousand years.
While field experiments continue at the Andra in the Meuse/Haute-Marne, researchers from Iramis are modelling these long-term processes based on laboratory experiments and the study of analogous archaeological parts that have been corroding for centuries. In particular, they have analyzed the corrosion of a steel model in storage conditions at Saclay, by combining several complementary techniques. These techniques include transmission electron microscopy and field emission microscopy, as well as scanning transmission X-ray microscopy.
Steel is known to corrode by forming iron carbonates that are more or less porous. However, Iramis's analyses show a submicronic layer of iron oxides (magnetite and maghemite) located between the steel and these corrosion products. The thickness of this layer varies from a few tens of nanometers to a micrometer, depending on the compactness of the clay environment. According to the study, it is this distinct interface that controls the corrosion rate of the steel.
Interfacial layers at a nanometre scale on iron corroded in carbonated anoxic environment, RSC Advances.
CEA is a French government-funded technological research organisation in four main areas: low-carbon energies, defense and security, information technologies and health technologies. A prominent player in the European Research Area, it is involved in setting up collaborative projects with many partners around the world.