Workers have begun processing a powder form of uranium-233 a year ahead of schedule as part of a larger environmental management, or cleanup, project to process and dispose of the remaining inventory of the nuclear material stored at Oak Ridge National Laboratory.

It’s the highest priority cleanup project at ORNL, a U.S. Department of Energy laboratory.

Isotek is the contractor responsible for processing and disposing of the uranium-233 inventory at ORNL. The work eliminates the need to use Building 3019, which is the oldest operating nuclear facility in the world, for storage of the material, according to DOE’s Oak Ridge Office of Environmental Management, or OREM.

In the 1970s and 1980s, nuclear facilities sent liquid uranium-233 to ORNL, and the site converted it into an oxide form, known as Oak Ridge Oxide, which is more stable for storage, OREM said in an “EM Update” newsletter published Tuesday. Some of the material was shipped to facilities for use as fuel in reactors. However, most of it was stored at ORNL until workers were able to dispose of it.