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From the Department of Energy’s Oak Ridge National Laboratory
September 2016
ADHESIVES – Metals that bind …
Oak Ridge National Laboratory and 3M are teaming up to study whether adhesives can
be developed to join heating, ventilation, air-conditioning and refrigeration components.
Using neutron imaging capabilities at the lab’s High Flux Isotope Reactor, the research
team will characterize novel aluminum-to-copper adhesive bonding materials at the
microscopic level. The ability to non-invasively quantify the adhesive’s coverage and
evaluate geometric pathways that affect joining strength could ultimately improve
efficiency and performance when applied in heating, ventilation, air conditioning and
refrigeration systems. [Contact: Sara Shoemaker, (865) 576-9219,
shoemakerms@ornl.gov]
A new ORNL and 3M project will investigate ways to improve adhesive joining materials
used in heating, ventilation, air conditioning and refrigeration systems.
SOLAR – Cleaner coatings …
Keeping energy-concentrating mirrors at solar thermal power plants free from dirt is
both labor and time intensive. Researchers at Oak Ridge National Laboratory are
working to address the challenge with lab-developed superhydrophobic coating
technology. “We’ve shown that applying superhydrophobic coating to the surface of
solar mirrors reduces dust particle accumulation,” said ORNL’s Georgios Polyzos.
“Now, we’re working to improve the coating’s durability, which could make it a cost-
effective solution for boosting energy production and operational efficiency at
concentrated solar power plants.” The ORNL team is subjecting thinly sprayed mirror
samples to simulated harsh desert conditions. Following successful lab testing, they
plan to evaluate the coatings on mirrors in the field. [Contact: Sara Shoemaker, (865)
576-9219, shoemakerms@ornl.gov]
Cleaning and maintaining solar mirrors could become less labor and time intensive with
the application of ORNL-developed superhydrophobic coating technology.
NUCLEAR — Testing future reactors …
Fluoride salt-cooled high-temperature reactors (FHR) are a promising design in the next
generation of nuclear energy production, and one of the first steps from concept to
reality is underway at Oak Ridge National Laboratory. A team led by ORNL’s Graydon
Yoder Jr. is operating a test loop to see how fluoride salts would perform in transferring
heat from the FHR’s core. “It’s the first high-temperature fluoride salt pumped test loop
facility in the U.S. since the 1970s,” Yoder said. “The loop can provide useful
information to reactor developers showing that liquid salt heat transfer meets
performance goals and safety requirements.” The FHR would provide temperatures well
above 600 degrees Celsius, which increases energy efficiency while maintaining a low
pressure because the fluoride salt is far from its boiling point. The research team is also
testing other new concepts, including silicon carbide as a piping component and a dry
rotating gas seal design. [Contact: Jason Ellis, (803) 804-4122; ellisjk@ornl.gov]
ORNL researchers use infrared photos to identify temperature loss that could create
problems in the high-temperature fluoride salt pumped test loop.
MATERIALS – Modeling radiation damage …
In nuclear reactors, energetic neutrons slam into metal atoms that are ordered in a
lattice, displacing them with enough force to trigger a cascade of collisions. Laurent
Béland,Yuri Osetsky and Roger Stoller, of the Energy Dissipation to Defect Evolution
Energy Frontier Research Center at the Department of Energy’s Oak Ridge National
Laboratory, modeled radiation damage and discovered that the number of defects
ultimately created in a material correlates with atomic displacements that high-pressure
shock waves generate early in the collision cascade. “In a typical simulation, the forces
emerging from interatomic interactions at these distances are inaccurately modeled,
which impacts the final outcome of the cascades,” Béland said. “This region where we
had only an ad hoc description of collisions is where all the important things happen,”
Stoller added. Their better understanding will improve simulations of chemically
complex alloys. [Contact: Dawn Levy, (865) 576-6448; levyd@ornl.gov]
Bombarding a nickel lattice with high-energy neutrons creates a cascade of collisions
that displace atoms. High-pressure energy waves generated early in the collision
cascade determine the fate of defects that ultimately form in the material. Image credit:
Oak Ridge National Laboratory, U.S. Dept. of Energy