Though currently only proven in low-temperature metals like aluminum, the team says that the ability of the nanotubes to slow the breakdown process could improve the operating lifetimes of research and commercial reactors.
Radiation isn't just bad for living things, it's also bad for metals – which is unfortunate because nuclear reactors are full of the stuff. The constant exposure of metals to strong radiation makes them brittle and porous to the point where they crack and fail. Needless to say, this impacts the safety and economy of reactors, so preventing this is a high priority for scientists and engineers.
The problem is that as they are bombarded by radioactive particles the atoms in the metal transmutate and split. This causes tiny bubbles of helium to form in a sort of metallic case of the bends. Just as the bubbles of nitrogen that form in a diver's blood if he ascends too quickly can cause damage, so do these helium bubbles that form along the borders of the crystalline grains that make up the metals. Eventually, the metal becomes porous and brittle and much more prone to fracturing.