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Y-12 National Security Complex (Y-12) is lending its computing power and technical expertise to improve fuel production for Oak Ridge National Laboratory’s High Flux Isotope Reactor (HFIR). Scientists use the reactor for basic science research and for producing medical isotopes to treat cancer patients. The research reactor is also being used for COVID-19 research and other studies.

For decades, Y-12 has been the sole supplier of the uranium oxide powder used in the fabrication of fuel for the HFIR. Recently, though, Y-12 used computed tomography (CT), or computerized X-ray imaging, to generate three dimensional images of surface and interior welds in the fuel elements for the HFIR. The scans—of three welds in the highly enriched uranium inner fuel elements—will help to ensure the elements will perform as designed before they are installed in the reactor.

The High Flux Isotope Reactor computed tomography scanning project is a Y-12 National Security Complex/Oak Ridge National Laboratory team effort.
The High Flux Isotope Reactor computed tomography scanning project is a Y-12 National Security Complex/Oak Ridge National Laboratory team effort.

An important mission

The Y-12 team worked closely with Dan Pinkston, an ORNL engineer who provides technical oversight for fabrication of fuel, control rods, and other internal components that go into the core of HFIR.

“We’ve worked well together,” Pinkston said. “Y-12 has been supportive of this effort because they understand the importance of HFIR’s mission. The reactor is the only reliable U.S. source for some industrial and medical isotopes, including the cancer-fighting isotopes actinium-227, californium-252, and strontium-90.”

Incorporating a new technology, overcoming challenges

We’ve worked well together. Y-12 has been supportive of this effort because they understand the importance of HFIR’s mission.

Dan Pinkston
Engineer, Oak Ridge National Laboratory

Before CT imaging, nondestructive examination of the fuel element welds was not possible, forcing the manufacturer to rely on less effective ways to ensure weld quality.

ORNL, seeking to improve weld inspection methods and to implement best practices, turned to Y-12 for help. Y-12 Engineering recommended CT imaging to assess weld integrity, having explored the technology for use in the site’s production operations. Taken from many angles, CT turns two-dimensional X-rays into a detailed 3D image with increased clarity.

“As part of our continuous improvement efforts, we made a commitment to the Department of Energy to implement CT scanning to improve the quality of the fuel element inspection process,” Pinkston said.

Y-12 was eager to assist in keeping the reactor operating at top performance levels. Though the site had the CT technology, the processes and procedures weren’t in place for handling the fuel elements.

Y-12 National Security Complex Material Clerk Kenny Blakely positions an inner fuel element so it can be secured for computed tomography scanning.
Y-12 National Security Complex Material Clerk Kenny Blakely positions an inner fuel element so it can be secured for computed tomography scanning.

A capability for Y-12 and strategic partners

“Not many places in the world are [using] CT scanning on enriched uranium fuel elements,” said Don Bible, project manager in Y-12’s Reactor and Material Supply. “The Y-12 and ORNL team pushed through a lot of technical challenges to accomplish this task.”

Y-12 CT engineer Aaron O’Toole agreed. “This project kind of kick-started our CT capability, forcing us to get procedures in place sooner than planned, learn advanced techniques for optimizing CT scans, and gain a deep understanding of our CT machine to squeeze every bit of performance out of it we can,” he said. “At the end of the day, we’ve matured our CT capability a ton and have a lot of confidence to tackle even harder problems in the future.”

The specialized expertise Y-12 gained on this project stands to benefit the National Nuclear Security Administration’s Nuclear Security Enterprise as well as Y-12’s other strategic partners.

“This project brought additional funding into Y-12 this fiscal year, and we are talking with other customers who have unique parts that require CT data,” Bible said. “Soon, I believe Y-12’s distinctive expertise will bring opportunities for other partnerships.” 

High Flux Isotope Reactor inner and outer fuel elements.
High Flux Isotope Reactor inner and outer fuel elements.