Through its commitment to international nuclear nonproliferation - a mission focused on limiting the spread of nuclear weapons and sensitive technology while working to promote peaceful use of nuclear science and technology - the United States maintains a constant vigilance aimed at reducing the threat of nuclear and radiological terrorism worldwide.
With extensive research into both basic and applied uranium science, as well as internationally deployed operational solutions, the Department of Energy's Oak Ridge National Laboratory is uniquely positioned to contribute its comprehensive capabilities toward advancing the U.S. nonproliferation mission.
In 1943, seemingly overnight, ORNL emerged from a rural Tennessee valley as the site of the world's first continuously operating nuclear reactor, in support of U.S. efforts to end World War II. ORNL's mission soon shifted into peacetime applications, harnessing nuclear science for medical treatments, power generation and breakthroughs in materials, biological and computational sciences.
Eight decades later, dedicated professionals fan out across the globe to further the U.S. nuclear nonproliferation mission. Today, this mission includes countering the threat of the nefarious use of nuclear materials, and the foundational science required to advance this mission begins at ORNL.
DOE's National Nuclear Security Administration works to impede nuclear proliferation by preventing, countering and responding to threats. At ORNL, researchers pursue materials characterization, uranium processing and applied sciences in support of these nonproliferation missions.
"In the broader context of uranium science, ORNL has been leaned upon historically for our expertise, from the fundamental materials to the processing methods," said Jared Johnson, director of the lab's Nonproliferation Program Office.
Working with various domestic and international agencies, ORNL scientists examine and perform experiments with uranium samples to learn about the origins of nuclear materials and their probable processing history.
"When we talk about the nonproliferation mission, what we're talking about is a broad suite of topics, but it can vary from understanding the origin of a material, helping to supply information from samples collected from the IAEA, to even understanding how we could detect nefarious operations that haven't been declared," Johnson said. "The expertise in understanding uranium compounds at a very fundamental level in terms of chemistry, structure, morphology and isotopic information is critical for the nonproliferation missions we support."
Basic science
Each step of the nuclear fuel cycle - through which raw uranium ore is purified, processed and converted into useable nuclear fuel - produces changes in the material, which can be revealed in even the tiniest of samples.
At ORNL, Andrew Miskowiec and his team conduct fundamental materials science, much of which centers on analysis of uranium and uranium-adjacent material, to uncover a sample material's history.
"What started with the Manhattan Project has since progressed into an ongoing quest to answer ever-broadening questions about how an element interacts with others, like how it bonds, and to what degree it is magnetic. Each answer can contribute a piece of the nuclear forensics puzzle," said Miskowiec, leader of the Materials and Chemistry group in ORNL's Nuclear Nonproliferation Division.
Sometimes, materials of interest could be only tiny, single particles. For samples like these, researchers use leading-edge machines, including electron microscopes, to look for inherent signals - what Miskowiec artfully calls "a smattering of phenomenology" - that could offer clues as to how a sample may have been altered.
Miskowiec and his fellow electron-microscope-wielding scientists are looking for material signatures of nuclear fuel cycle operations, which are often only detectable in one of many intricately applied methods.
"Every element has a fingerprint, and these machines help us identify them at incredibly detailed levels, helping to tell the story of a particular material's history," Miskowiec said.
With the help of high-powered research tools, ORNL scientists examine materials to answer tough questions about what materials are made of and what happens to their properties and composition as temperatures or other factors are manipulated.
Miskowiec and his team are "bringing a unique set of tools to the premiere scientific institution in the world for materials, bringing all the big guns to bear - and applying all of this to the nonproliferation mission," he said.
Applied science
ORNL physicist Jennifer Niedziela understands how atoms function within different materials. In fact, she fingerprints them too.
"Inside any material you have, your atoms are in this specific arrangement governed by what that material is and the different atoms themselves. They respond differently to different types of probes," said Niedziela, who leads ORNL's Applied Materials Analysis group. "Atoms move around in certain ways and emit characteristic patterns that allow us to fingerprint them, like you would see in NCIS or any of those forensic shows, so you can get a really quick overview of what a material might be from those basic tools."
Niedziela and her team take the fundamental research produced by Miskowiec's group and translate it into reliable, operational workflows. Both teams ask, "What kind of information can you get out of a material that is sampled from different points in the fuel cycle process, and what can you extract about the processing history?"
To answer these questions, Niedziela's and Miskowiec's teams use an array of the biggest scientific tools in the world, including ORNL's Spallation Neutron Source and Frontier supercomputer. They explore how atoms contribute to observable stimuli and how specific arrangements of atoms shift depending on how they are manipulated. Ultimately, they reach a fundamental understanding of specific indicators of materials and how they change under different process conditions.
"We have a lot of technical capability and state-of-the-art characterization equipment that is targeted at this nonproliferation mission phase in advancing that foundational science around uranium chemistry," Niedziela said.
Operational solutions
Armed with the scientific expertise of his colleagues, Steve Cleveland and his team work to support the removal of uranium from foreign partners under the NNSA's Mobile Packaging Program. The boots-on-the-ground capability that he leads at ORNL is the Mobile Uranium Facility, or MUF, a deployable, shippable system of tools that the team can use to safely characterize and remove uranium in any form, from anywhere in the world. Operated in partnership with Y-12 National Security Complex, the MUF's rapid-response capability makes it a unique international asset.
By retaining the requisite experts and versatile equipment necessary for characterization and stabilization of various configurations of uranium - combined with packaging and removal capabilities for shipping in safe, approved cannisters and shipping arrangements - the MUF team can respond on-demand.
According to Cleveland, the satisfaction he derives from his work is rooted in the knowledge that with every effort to which he contributes, he and his team are actively helping to reduce the nuclear threat from bad actors. The first thing he noticed, and notices daily, is "the pride and drive among everyone on our team to make the world a safer place." "It's something we all share and work toward together," Cleveland added. "Seeing us take the basic science and research and apply it to operations and then actually seeing the world reduce the nuclear threat - that's absolutely one of my joys in coming to work."
From science to solution
As leaders in a concerted, global effort to increase the peace, uranium science researchers at ORNL are international detectives who solve complex, elusive nuclear material mysteries with at times dramatic implications. They look back to discover what may have happened to a sample of nuclear material, create new technology to better analyze and understand it in the future, and deploy operational solutions to real-world problems at a moment's notice.
"One of the best parts about this particular focus area here is that it really gets at the core of what Oak Ridge is about," Niedziela said. "We use big science tools to answer these hard problems, advance that foundational science around uranium chemistry and improve national security."
The Frontier supercomputer is part of the Oak Ridge Leadership Computing Facility, or OLCF, located at ORNL. OLCF and ORNL's Spallation Neutron Source are DOE Office of Science user facilities.
UT-Battelle manages ORNL for the Department of Energy's Office of Science, the single largest supporter of basic research in the physical sciences in the United States. The Office of Science is working to address some of the most pressing challenges of our time. For more information, visit energy.gov/science . - Chris Driver
