The remaining stockpile of uranium-233 at the Oak Ridge National Laboratory (ORNL) in Tennessee could be processed for disposal as low-level waste by 2025, according to an executive with the company managing the operation.
Cleaning out the uranium from Building 3019 is the top cleanup priority at ORNL because, among other things, storing the fissile nuclear material increases security costs and creates nuclear safety issues. Building 3019 was built to help with the top-secret Manhattan Project during World War II, and it is the oldest operating nuclear facility in the world, according to the Department of Energy.
The uranium stored at ORNL came to the lab from DOE-related missions at sites across the country. About half of the more than 1,000 canisters of the material that had been stored at the lab has been transferred for disposal, mostly at the Nevada National Security Site. That waste did not require processing, said Jim Bolon, president of Isotek Systems, the contractor responsible for securing, processing, and disposing of the uranium-233 stored in Building 3019.
More than 500 canisters remain. That waste will have to be processed before it can be shipped for disposal at a designated facility, Bolon told the Oak Ridge Site Specific Advisory Board on Wednesday evening. The processing will result in a solidified low-level waste in a grouted liner, Bolon said.
The uranium that is left in Building 3019 is stored in different forms, including oxide powders, metal, monoliths, and sodium fluoride traps from ORNL’s Molten Salt Reactor Experiment. It is being processed in Building 2026 at ORNL, across the street from Building 3019.
The processing of low-dose oxide powders started in glove boxes in Building 2026 in October, Bolon said. But most of the remaining canisters stored at ORNL are more radioactive, and will have to be processed in hot cells in Building 2026, possibly starting near the end of the year, he added. The uranium processing work could take about five years.
When they are processed, materials in the uranium canisters are divided into smaller batches, blended with a weakened solution to lower the radiation dose, and mixed with concrete for disposal as low-level waste.
The project has been boosted by an agreement with TerraPower, a company co-founded by Microsoft’s Bill Gates. Isotek is removing thorium-229 from the uranium-233 as it processes the material for disposal and selling the thorium to TerraPower, which then extracts actinium-225 for use in cancer treatment research.
Although the purchase price is confidential, Isotek will use the money from the sale of the thorium-229 to pay for part of the uranium-233 disposal. That allows the uranium processing operations to begin a year ahead of schedule and saves about $90 million through direct private funding and reduced costs as the material is removed from storage, according to DOE.
Isotek has been responsible since 2003 for overseeing the uranium-233 inventory at ORNL and preparing for its removal. The company’s uranium disposition contract, which has been valued at $557 million and in effect through December 2024, is managed by DOE’s Oak Ridge Office of Environmental Management.
Uranium-233 is a radioactive isotope of uranium that does not exist in nature, but it can be produced by bombarding thorium-232 with neutrons. Although it was created as an additional fuel source for nuclear reactors, uranium-233 has proved to be unviable as a fuel source because its creation also generated uranium-232, a highly unstable radioactive isotope, according to DOE and its contractors.
