Source: EM Update | Vol. 12, Issue 31; Contributor: John Gray | October 20, 2020
After a pause due to the COVID-19 pandemic, DOE’s Oak Ridge Office of Environmental Management (OREM) and its contractor Isotek are resuming uranium (U)-233 processing and downblending operations using gloveboxes.
During the recent pause in operations, OREM and Isotek worked collaboratively to install upgrades and identify and implement numerous prevention methods to ensure workers remain safe while they eliminate the inventory of U-233 from the Oak Ridge National Laboratory (ORNL), which is EM’s highest priority at that site.
The project is removing a significant risk by eliminating the inventory of highly enriched fissile material stored in Building 3019, the world’s oldest operating nuclear facility located in the heart of one of the nation’s most important scientific research sites.
Employees, known as fissile material handlers, use shielded gloveboxes to dissolve U-233 into a low-level form so it can be mixed with grout for safe transportation and disposal. The material dates back decades and was originally pursued as a fuel for reactors; however, it did not prove to be a viable option.
Last year, OREM, Isotek, and TerraPower announced an innovative public-private partnership that makes use of the U-233 inventory before it is disposed. Isotek employees extract thorium before the material is processed into a disposal-ready form. Nuclear innovation company TerraPower is using the extracted thorium to support next generation cancer treatment research.
At the restart of U-233 processing, employees went through training again to ensure they were prepared and mindful to handle the radioactive material. They also trained on new procedures that incorporated COVID-19 related safety precautions.
During the suspension of work, a new filter was implemented for the dissolved U-233 that would catch undissolved particles. This filter will prevent undissolved particles from plugging up transfer lines, decreasing the time employees use the gloveboxes.
Another new implementation is an extended waste transfer line. This new line extends from the glovebox all the way to a negative pressure area so waste can be transferred directly to a safe zone. Before this, employees transferred waste to a drum and then moved the drum to the safe zone.
In conjunction with glovebox processing restarting, construction continues on getting Building 3019 ready for hot cell processing. Hot cells are needed to handle high-dose U-233 canisters, while gloveboxes are used for the low-dose portion of the inventory. Entry tubes are being fitted for remote manipulators that will handle material inside the hot cells. And an entire floor has been reconstructed for an air pallet that will be able to move 30 tons of waste after it has been processed for disposal.
Hot cell processing is expected to begin next year. Until then, Isotek will continue addressing the low-dose inventory using gloveboxes.