US DUF6 conversion ahead of schedule

25 January 2019

The return to service of all seven uranium conversion production lines enabled the US Department of Energy Office of Environmental Management (EM) to convert over 5000 tonnes of depleted uranium hexafluoride (DUF6) - more than half its yearly target - to a more stable form within the first three months of fiscal 2019.

Personnel at EM’s Portsmouth Site celebrate the return of all seven DUF6 Conversion Project production lines to simultaneous operation (Image: EM)

The DUF6 Conversion Project converted 5110 tonnes of DUF6 from October to December. This is over half of its 9000 tonne goal for fiscal 2019, which runs from 1 October 2018 to 30 September 2019. EM was able to achieve this through the return to simultaneous operation of all seven production lines at its Ohio and Kentucky facilities after several pauses for safety and maintenance purposes, as well as upgrades and improvements, including the installation of new, more reliable hydrogen-generation systems at both facilities.

The DOE's 800,000 tonne inventory of DUF6 is a legacy of over 60 years of operations at gaseous diffusion uranium enrichment plants at Portsmouth, Ohio and Paducah, Kentucky. The enrichment plants supplied enriched uranium for the early nuclear weapons programmes and later for the commercial nuclear energy industry. The Portsmouth plant ceased operations in 2001 and Paducah in 2013.

EM's facilities convert stored DUF6 to depleted uranium oxide, which is more chemically stable for future storage, re-use or disposal. A byproduct of the process is hydrofluoric acid, which can be used industrially. The project has converted more than 70,000 tonnes of the DOE's inventory since the conversion facilities were commissioned in 2010.

"This past year, the DUF6 project implemented facility improvements and operational efficiencies that build a foundation for sustained safe production," Robert Edwards, manager of EM’s Portsmouth/Paducah Project Office, said.

Portsmouth's DUF6 inventory is expected to be processed in about 18 years and Paducah's inventory, which is larger, within 30 years.

Researched and written by World Nuclear News