OAK RIDGE, Tenn. – EM contractor Isotek began processing the remaining inventory of uranium (U)-233 stored at Oak Ridge National Laboratory (ORNL) last week, attaining a 2022 priority for the cleanup program.
Starting processing operations moves EM closer to achieving its highest cleanup priority at ORNL: safe and secure disposal of the Cold War legacy nuclear material stored in the world’s oldest operating nuclear facility, Building 3019.
Crews began the campaign by transferring a canister of U-233 oxide from Building 3019 into an adjacent, newly upgraded hot cell facility for downblending processing.
“Receiving startup approval for the initial processing campaign is a defining moment for the U-233 Disposition Project,” Isotek President Jim Bolon said. “Isotek personnel have invested over 500,000 hours of effort over several years to make this dream come true. I am extraordinarily proud of their hard work and commitment to the U-233 disposition mission.”
Using the hot cells, which are heavily shielded rooms, workers are protected from radiation exposure as they handle the radioactive nuclear material. Employees open canisters inside the hot cells, strip the transuranic material — which has a higher atomic number than uranium — from the U-233, and mix it with depleted uranyl nitrate.
This downblending lessens the enrichment of the U-233 material, converting the material into a form safe for transportation and permanent disposal. Downblended uranyl nitrate is solidified onsite and transported offsite for disposal.
EM and Isotek’s work to safely process this Cold War-era nuclear material will reduce risks and eliminate costs to taxpayers of keeping the material safe and secure in storage.
U-233 was created as an alternative nuclear fuel source in the 1950s and 1960s. However, due to its trace amounts of U-232, a highly unstable radioactive isotope, it was too difficult to use. Eventually, it was sent to ORNL for storage.
EM and Isotek completed an earlier phase of the project last year. Together, they successfully finished processing and disposing the low-dose inventory of U-233. That two-year effort eliminated a portion of the site’s legacy nuclear material and provided rare nuclear isotopes for next-generation cancer treatment research.
An initial approach involved processing all of the remaining U-233 inventory in 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. Now that the hot cells have been upgraded, employees can begin processing the high-dose inventory.
The U-233 Disposition Project is not only reducing risks and eliminating future costs, but also benefiting the medical field. Under a partnership with TerraPower, Isotek is extracting thorium-229 from U-233 during processing.
Thorium-229 will be used to produce vital medical isotopes ideal for a promising new cancer treatment, known as alpha targeted therapy. The inventory of U-233 stored at ORNL is the only source of Thorium-229 in the world today. Processing of all U-233 canisters in Building 3019 is expected to yield enough thorium to produce up to 200 times more cancer treatment doses per year than what is currently available worldwide.
The U-233 processing campaign is expected to continue the next few years. By the end of the campaign, about 90% of the original nuclear inventory in Building 3019 will be dispositioned.
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