OAK RIDGE, Tenn. – The Oak Ridge Office of Environmental Management (OREM) and its contractor Isotek successfully completed processing and disposing the low-dose inventory of uranium (U)-233 stored at Oak Ridge National Laboratory (ORNL) this month, ending a two-year effort that has eliminated a portion of the site’s legacy nuclear material and provided rare nuclear isotopes for next-generation cancer treatment research.

Watch a video about that effort, known as the Thorium Express Project.

With the low-dose U-233 inventory disposed, OREM and Isotek will focus on treating and disposing the remaining high-dose U-233 inventory stored at ORNL.

“Processing and removing the low-dose portion of the U-233 inventory at ORNL is a major step forward on one of our highest priority projects,” EM ORNL Portfolio Federal Project Director Nathan Felosi said. “It is vital that we continue driving this project forward so EM can reduce significant risks and security costs, and enable deactivation of the oldest operating nuclear facility in the world.”

Eliminating the inventory of U-233 is EM’s highest priority at ORNL. U-233 is a manmade isotope created as an alternative nuclear fuel source in the 1950s. The nation’s inventory of U-233 was later sent to ORNL for long-term storage.

OREM finished disposing approximately half of the U-233 inventory in 2017, while the remainder of the material required processing and downblending to convert it into a form for safe shipment and disposal.

An initial approach involved processing all of the remaining inventory in heavily shielded rooms, known as hot cells. However, the building where this would occur required significant upgrades before that work could begin.

Isotek identified a subset of the U-233 material with lower radioactivity levels that employees could begin processing in gloveboxes while other crews prepared the hot cells to address the U-233 material with higher radioactivity levels. This approach was made possible through a unique partnership with TerraPower, a private nuclear innovation company.

Isotek received funds from TerraPower to extract thorium isotopes from the U-233 inventory. Through this arrangement, TerraPower received rare medical isotopes to advance next-generation cancer treatment research, and Isotek received funds it reinvested in the project to purchase gloveboxes and accelerate the processing schedule, saving significant tax dollars.

“The Thorium Express Project was extraordinarily important to the overall U-233 disposition project,” Isotek President Jim Bolon said. “It kick-started the disposition phase of our contract with DOE, launched the thorium extraction initiative, and highlighted the great work being performed by employees at Isotek every day.”

With upgrades and installation of new equipment complete, Isotek is slated to begin its next phase of the disposition campaign in early 2022: processing canisters with the high-dose U-233 material. The heavily shielded hot cells protect workers and allow them to handle the material using remote manipulators. This upcoming phase will enable Isotek to enhance productivity by processing larger amounts of U-233 and extracting more medical isotopes.

Earlier this year, DOE awarded the Thorium Express Project a Secretary of Energy Achievement Award, one of the Department's highest honors.