The stresses endured by reactor pressure vessels and other nuclear components go beyond the heat and pressure that metal experiences in other industrial settings. Fission produces energetic particles that can alter metal at the molecular level, sometimes impregnating it with tiny helium bubbles that can make steel brittle.At Caltech, researchers are studying these effects and developed a material that may help mitigate them. In papers published in the "Advanced Functional Materials" and "Small" scientific journals, a team led by Caltech Professor Julia R. Greer, along with colleagues from Sandia National Laboratories, Los Alamos National Laboratory and U.C. Berkley, studied the potential effects of radiation on nanolaminates. According to an article produced by Caltech, the researchers used electroplating to create nano-scale pillars of pure copper and pillars of stacked iron and copper crystals. Scientists then implanted them with helium ions like those that bombard reactor components.Under testing, the resulting material was not made brittle by the helium. The researchers found the material could maintain its ductility because its interface was able to deform gradually under stress. While practical applications for reactor designers are a long way off, the discovery represents a new avenue to explore in the area of advanced materials designed for the unique conditions at the heart of a nuclear plant.