STEELIER THAN STEEL: A new kind of metal could make nuclear reactors stronger and last longer – by Akshat Rathi ( – March 21 2016)

Despite opposition and safety concerns, nuclear power remains a big part of the world’s energy mix—providing about 10% of world’s electricity. And since nuclear reactors typically last 40 years, there are still hundreds of decades-old reactors around the world that must be maintained.

Most of those reactors are made up primarily of some form of stainless steel. But steel is showing its limitations—primarily that it can weaken or become defective over time, and in extreme cases break apart. This is an even bigger concern in newer reactors that run at higher temperatures and have more fast-moving neutrons.

So scientists have been on the hunt for metal alloys that are stronger and can last longer, and researchers in Finland and the US may have found a new category of such alloys. In a study to be published in Physics Review Letters, they report that high-entropy alloys could do the job better than steel.

A nuclear reactor sees the bombardment of neutrons onto radioactive fuel. As heavy atoms split apart, they produce more neutrons and vast amounts of heat (which powers turbines and thus produces electricity). While a vast majority of unnecessary neutrons are stopped by heavy water that fills the reactor, some make their way to the metal exterior that holds the reactor together.

When they hit that metal, they can dislodge the atoms that form the metal’s crystalline structure. Such dislodging causes defects, which can cause the reactor to break apart if they’re not fixed.

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