Skip to main content

How Nanomaterials Can Make Nuclear Reactors Safer and More Efficient

The following is a guest post from Matt Wald, senior communications advisor at NEI. Follow Matt on Twitter at @MattLWald.

From the batteries in our cell phones to the clothes on our backs, "nanomaterials" that are designed molecule by molecule are working their way into our economy and our lives. Now there’s some promising work on new materials for nuclear reactors.

Reactors are a tough environment. The sub atomic particles that sustain the chain reaction, neutrons, are great for splitting additional uranium atoms, but not all of them hit a uranium atom; some of them end up in various metal components of the reactor. The metal is usually a crystalline structure, meaning it is as orderly as a ladder or a sheet of graph paper, but the neutrons rearrange the atoms, leaving some infinitesimal voids in the structure and some areas of extra density. The components literally grow, getting longer and thicker. The phenomenon is well understood and designers compensate for it with a variety of techniques. One simple one is replacing some metal parts every few years.

But materials scientists at the Nebraska Center for Energy Sciences Research, at the University of Nebraska in Lincoln, are working on a variety of “radiation-tolerant” materials that are self-healing. These would improve the durability of the metal parts, which would be helpful for the current fleet and more important for advanced reactors still in the design phase. Fuel elements in existing reactors are replaced after a few years, but some of the new designs would leave metal parts in place for far longer. And better materials can improve the reliability of any industry.

The researchers are working with the fact that a different class of materials, called “amorphous materials,” do not suffer damage when bombarded with neutrons. Amorphous materials, which are already in common use, do not suffer the same kind of damage. The atoms in an amorphous material are not arranged in a repeated pattern. Polymers and gels are two kinds of amorphous solids.

What the Nebraska researchers have discovered, in work partly funded by the Nebraska Public Power District and the Department of Energy's office of Nuclear Energy, is that if crystalline materials are sandwiched with amorphous materials, the flaws in the crystalline materials --- both the voids and the areas with extra density --- migrate toward the border of the two. And when they meet, they annihilate each other.

The researchers use a particle accelerator rather than a reactor, to create the damage, and then study it with powerful microscopes. They work with layers a few microns thick.

Bai Cui, an assistant professor of mechanical and materials engineering, said that at the boundary, the two flaws neutralize each other quickly. The atoms are vibrating at a rate of about 130 trillion times per second (ten to the 13th), and the flaws locate each other in about 100 cycles – that is, on the order of a trillionth of a second.

Jian Wang, an associate professor at the center, pointed out that some advanced reactor designs would have operating temperatures of over 200 degrees C and would use corrosive coolants, like molten salt or supercritical water, and are intended to run for 80 years or more. Micro-layers of amorphous materials could work well in that environment, he said.
The center is also working on nano-materials that can be mixed into steel to attract and neutralize flaws. The material can be used in a weld, and is then mixed in using “laser peening.” Generally, peening means shooting particles at a target at high velocity, often to strip off the top layer of the target. But in laser peening, the pressure of light distributes the nano-materials within the steel.

The center is directed by Dr. Michael Nastasi, a research scientist formerly at the Energy Department’s Los Alamos National Laboratory. The cutting-edge nuclear research here is not its only focus; this being Nebraska, it also conducts research on wind turbines, biofuels, crop irrigation and other areas.

Comments

Popular posts from this blog

A Design Team Pictures the Future of Nuclear Energy

For more than 100 years, the shape and location of human settlements has been defined in large part by energy and water. Cities grew up near natural resources like hydropower, and near water for agricultural, industrial and household use.

So what would the world look like with a new generation of small nuclear reactors that could provide abundant, clean energy for electricity, water pumping and desalination and industrial processes?

Hard to say with precision, but Third Way, the non-partisan think tank, asked the design team at the Washington, D.C. office of Gensler & Associates, an architecture and interior design firm that specializes in sustainable projects like a complex that houses the NFL’s Dallas Cowboys. The talented designers saw a blooming desert and a cozy arctic village, an old urban mill re-purposed as an energy producer, a data center that integrates solar panels on its sprawling flat roofs, a naval base and a humming transit hub.

In the converted mill, high temperat…

Sneak Peek

There's an invisible force powering and propelling our way of life.
It's all around us. You can't feel it. Smell it. Or taste it.
But it's there all the same. And if you look close enough, you can see all the amazing and wondrous things it does.
It not only powers our cities and towns.
And all the high-tech things we love.
It gives us the power to invent.
To explore.
To discover.
To create advanced technologies.
This invisible force creates jobs out of thin air.
It adds billions to our economy.
It's on even when we're not.
And stays on no matter what Mother Nature throws at it.
This invisible force takes us to the outer reaches of outer space.
And to the very depths of our oceans.
It brings us together. And it makes us better.
And most importantly, it has the power to do all this in our lifetime while barely leaving a trace.
Some people might say it's kind of unbelievable.
They wonder, what is this new power that does all these extraordinary things?

New Home for Our Blog: Join Us on NEI.org

On February 27, NEI launched the new NEI.org. We overhauled the public site, framing all of our content around the National Nuclear Energy Strategy.

So, what's changed?

Our top priority was to put you, the user, first. Now you can quickly get the information you need. You'll enjoy visiting the site with its intuitive navigation, social media integration and compelling and shareable visuals. We've added a feature called Nuclear Now, which showcases the latest industry news and resources like fact sheets and reports. It's one of the first sections you'll see on our home page and it can be accessed anywhere throughout the site by clicking on the atom symbol in the top right corner of the page.
Most importantly for you, our loyal NEI Nuclear Notes readers, is that we've migrated the blog to the new site. Moving forward, all blog posts will be published in the News section, along with our press releases, Nuclear Energy Overview stories and more. Just look for the &qu…