Speeding New Materials for Nukes

Next-generation nuclear power plants could produce much less waste than conventional reactors, eliminating a serious objection to a potentially abundant and otherwise clean source of energy. But the new technology requires materials that can withstand both high temperatures and radiation. Using conventional methods, it could take decades to develop such materials. But new computer simulations could cut this time down to months, says Steven John Zinkle, a researcher at Oak Ridge National Laboratory. Zinkle presented his recent work at the Materials Research Society conference in Boston.

The materials proven to work in today’s nuclear power plants operate within a small range of temperatures that won’t work in many new designs. Outside that range, the materials can become brittle or develop holes that make them look like “Swiss cheese,” Zinkle says. But researchers are learning that changing the composition of an alloy by a fraction of a percent can change its operating temperature by hundreds of degrees. Tweaking the heat treatment of the materials can also have a big effect. The problem is that sorting through the large number of possible subtle changes can take a very long time.

Zinkle says that computer modeling is making it possible to shrink development times from decades to months. Models allow researchers to quickly evaluate subtle changes without having to go through the time-consuming process of making a lot of slightly different materials. As a result, researchers have been able to identify small changes that, for example, transform materials that would normally break apart after a couple of days into materials that last for years without showing significant damage.

Oak Ridge researchers have already demonstrated the techniques with new materials for diesel engines, and they’re applying the techniques to speed the development of more environmentally benign nuclear power plants.