Isotek U-233: Turning Cold War Waste into Cancer Treatments

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Markets

Nuclear
Location

Oak Ridge, TN
Client

U.S. Department of Energy Office of Environmental Management

Managing nuclear waste has traditionally focused on containment and disposal. However, by using advanced processing methods, it can be transformed into a powerful tool for fighting cancer. Our Isotek Systems (Isotek) team is leading this transformative mission on a uranium-233 (U-233) project at the Oak Ridge National Laboratory (ORNL) in Tennessee.

Through a public-private partnership with the U.S. Department of Energy (DOE) and TerraPower, the Isotek U-233 project is addressing two critical needs: cleaning up legacy radioactive waste and extracting thorium-229 (Th-229). Th-229 is a rare isotope used to produce actinium-225 (Ac-225), which has shown promise in targeted alpha therapy (TAT) for cancer treatments.

U-233 was originally created as an alternative fuel source for nuclear reactors in the 1950s and 60s by bombarding naturally occurring thorium-232 with neutrons. However, this process also created trace amounts of the highly unstable radioactive isotope uranium-232, making U-233 an unreliable fuel source. Therefore, U-233 was sent to ORNL for storage, where it stayed for decades and cost a lot to safely maintain.

At the beginning of the project, about half of the U-233 inventory was safe for transportation and disposal. However, the rest needed to be dissolved, downblended and solidified first. Processing that inventory began in late 2019, a year ahead of schedule.

Isotek extracts Th-229 from U-233 when downblending the material. TerraPower then uses Th-229 to produce Ac-225. Ac-225 is a short-lived, alpha-emitting isotope ideal for TAT, a promising new cancer treatment where radiation is directly delivered to cancer cells with minimal damage to healthy tissue.

Currently, TAT shows promise in clinical trials involving various types of cancers, including prostate, breast and small-cell lung cancer, as well as gastroenteropancreatic neuroendocrine tumors and other undeclared solid tumor cancers. By enabling the production of Ac-225, annual cancer treatment doses have increased to 100,000, up from only 4,000 available worldwide beforehand.

To safely extract Th-229, Isotek designed and installed shielded gloveboxes as part of the award-winning Thorium Express pilot project. This approach was highly successful, extracting the isotope with 95% efficiency. However, it only processed 5% of the remaining U-233 inventory.

To support rapid scaling, existing hot-cell facilities at ORNL were refurbished and reactivated. These specialized containment systems, along with shielded gloveboxes, have helped the project surpass five million safe work hours by protecting workers from radiation, preventing contamination, and enforcing rigorous safety and criticality controls during material handling, dissolution and downblending operations.

Thanks to Isotek’s efforts, millions of taxpayer dollars have been saved, and the global supply of Th-229 has grown by 2,000%, marking a major advancement in the availability of this rare isotope. The long-term goal is to expand production enough to dramatically increase access to cancer treatments. In addition, over 70% of the U-233 inventory has been safely dispositioned, reflecting steady progress toward key program milestones.

Equipment being unload on the project site

Isotek personnel remove a U-233 canister from storage and transfer it to the processing facility. The canister is in a lead-shielded carrier to protect workers from radiological dose.

In the processing facility, the canister is placed in a hot cell where it will be dissolved in a solution to remove its ability to support criticality. After processing, the solution is solidified.