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Heat is typically carried through a material by vibrations known as phonons. In some crystals, however, different atomic motions — known as phasons — carry heat three times faster and farther. This illustration shows phasons made by rearranging atoms, shown by arrows. Credit: Jill Hemman/ORNL, U.S. Dept. of Energy

Warming a crystal of the mineral fresnoite, ORNL scientists discovered that excitations called phasons carried heat three times farther and faster than phonons, the excitations that usually carry heat through a material.

Even small movements of hydrogen, shown in yellow, were found to cause large energy shifts in the attached iron atoms, shown in silver, which could be of interest in creating novel chemical reactions. Credit: Jill Hemman/ORNL, U.S. Dept. of Energy

Researchers from Yale University and ORNL collaborated on neutron scattering experiments to study hydrogen atom locations and their effects on iron in a compound similar to those commonly used in industrial catalysts.

ORNL researchers used neutrons at the lab’s Spallation Neutron Source to analyze modified high-entropy metal alloys with enhanced strength and ductility, or the ability to stretch, under high-stress without failing. Credit: Rui Feng/ORNL, U.S. Dept. of Energy
Researchers at Oak Ridge National Laboratory have developed a method of adding nanostructures to high-entropy metal alloys, or HEAs, that enhance both strength and ductility, which is the ability to deform or stretch
Fuel pellets sometimes degrade to a sandlike consistency and can disperse into the reactor core if a rod’s cladding bursts. ORNL researchers are studying how often this happens and what impact it has, in order to let reactors operate as long as possible without increasing risk.

A developing method to gauge the occurrence of a nuclear reactor anomaly has the potential to save millions of dollars.

 Using the ASGarD mathematical framework, scientists can model and visualize the electric fields, shown as arrows, circling around magnetic fields that are colorized to represent field magnitude of a fusion plasma. Credit: David Green/ORNL

Combining expertise in physics, applied math and computing, Oak Ridge National Laboratory scientists are expanding the possibilities for simulating electromagnetic fields that underpin phenomena in materials design and telecommunications.

The 1250 ton cyrostat base is positioned over the ITER tokamak pit for installation. This base is the heaviest lift of tokamak assembly. Credit: ITER Organization

ITER, the world’s largest international scientific collaboration, is beginning assembly of the fusion reactor tokamak that will include 12 different essential hardware systems provided by US ITER, which is managed by Oak Ridge National Laboratory.

Nuclear — Seeing inside particles

Oak Ridge National Laboratory researchers working on neutron imaging capabilities for nuclear materials have developed a process for seeing the inside of uranium particles – without cutting them open.

This simulation of a fusion plasma calculation result shows the interaction of two counter-streaming beams of super-heated gas. Credit: David L. Green/Oak Ridge National Laboratory, U.S. Dept. of Energy

The prospect of simulating a fusion plasma is a step closer to reality thanks to a new computational tool developed by scientists in fusion physics, computer science and mathematics at ORNL.

Argon pellet injection text

As scientists study approaches to best sustain a fusion reactor, a team led by Oak Ridge National Laboratory investigated injecting shattered argon pellets into a super-hot plasma, when needed, to protect the reactor’s interior wall from high-energy runaway electrons.

Tungsten tiles for fusion

Using additive manufacturing, scientists experimenting with tungsten at Oak Ridge National Laboratory hope to unlock new potential of the high-performance heat-transferring material used to protect components from the plasma inside a fusion reactor. Fusion requires hydrogen isotopes to reach millions of degrees.