Healing Radiation Damage in Nanoscale Materials
Typically radiation is associated with some kind of damage, because the high energy emission often causes damage to whatever it hits. This means it is important to understand how radiation damage affects materials used in nuclear reactors. Researchers at the California Institute of Technology, Sandia National Laboratories, UC Berkeley, and Los Alamos National Laboratory have recently worked together to test what radiation does to nanoscale structures and found some surprising results.
A well-known phenomenon when radiation enters a material like steel is that an atom gets displaced and a pocket of helium appears. With enough pockets, the material becomes porous, brittle, and more likely to break. The researchers decided to mimic this in nanoscale materials by building up pillars of pure copper and pillars of copper with iron on top, with helium bubbles inside. As expected, there was actually some hardening as a result of the helium, but surprisingly there was none of the associated embrittlement. This suggests that the helium will migrate within the material to an interface, like that between the copper and iron, resulting in a healing effect.
While the information from this may not be directly useful for reactor designs, as we do not build nanoscale reactors, it will still be incorporated into future models. Those models will be used to design new materials for use in future reactors.