Specialized cylinders stand in a cylinder yard at the Paducah Site. (Photo: DOE)
A milestone has been reached at the Department of Energy’s Paducah Site when work crews successfully fabricated valves from old equipment and installed them on 137 specialized cylinders. This action will enable future work crews to transform depleted uranium hexafluoride (DUF6) stored inside the cylinders into depleted uranium oxide, a stable chemical form suitable for reuse, storage or disposal.
According to the DOE, the valves are essential for feeding the DUF6 material into a conversion system, which also produces the coproduct hydrofluoric acid that is reused industrially.
Some history: The DOE’s Portsmouth/Paducah Project Office (PPPO) manages the cleanup efforts at the two former gaseous diffusion plant sites–Paducah in Kentucky and Portsmouth in Ohio. The sites were active primarily for uranium enrichment, a process used to produce nuclear fuel initially for defense purposes and later for commercial nuclear power plants.
DUF6 was historically containerized during the enrichment process as tails, which are large quantities of depleted uranium. The DUF6 has been stored in cylinders of various types over the years.
The work: In this latest milestone, workers removed the cylinder plugs and attached the valves, which were fabricated from obsolete converter components at Paducah. The work was performed outdoors and required rigorous safety protocols due to the inherent risks associated with handling cylinders with unknown pressure conditions.
The 137 specialized cylinders are the largest DUF6 units by volume in the Paducah Site’s inventory, with a full cylinder weighing about 39,000 pounds.
The next step: Paducah will now proceed with the next phase: installing a DUF6 evacuation vacuum header. This work allows for a more efficient and flexible means to process the DUF6 material, the DOE noted. The specialized cylinders don’t fit in the project’s autoclave (a heated container), so workers will transfer the DUF6 material from the specialized cylinders to standard cylinders where it can be processed in the autoclave. Compared to a full specialized cylinder, a full standard cylinder weighs about 32,700 pounds.
Quote: “These 137 cylinders represent an innovative solution to reuse former gaseous diffusion plant equipment from decades ago to containerize DUF6 material,” said Zak Lafontaine, DUF6 program manager of the PPPO. “Their unique size and configuration presented a significant challenge to the Mid-America Conversion Services team, and I am pleased we have safely completed the first phase of this endeavor.”
Mid-America Conversion Services is the PPPO DUF6 contractor.
