For the first time in more than 57 years, silence fell on the equipment of the uranium enrichment cascade May 30, 2012 in the former gaseous diffusion plant at the Department of Energy Portsmouth Site in Piketon. The last part of the complex network of machines was shut down to end operations in the X-326 Process Building.
The X-326 Process Building, together with the X-330 and X-333 process buildings, housed the uranium enrichment cascade, nearly 100 acres in size. The cascade was a network of converters that processed a supply of uranium hexafluoride (UF6). The uranium was “enriched” at the atomic level to make it useable fuel for nuclear reactors. The converters were machines connected by an elaborate path of piping through which the UF6 was fed in a heated gaseous state. Converters and related equipment grouped in “stages” were arranged together in groups called “cells.”
“This cascade and all of its supportive systems are a tremendous legacy of the engineering prowess and ingenuity of our communities and our nation,” said DOE Site Lead Joel Bradburne, who attended the ceremonial shutdown. “More than half of a century of successes and achievements will never be duplicated.”
Facility Shift Supervisor John Hutchison says the shutdown process has been significant to the workers, most of whom have been together for more than a decade.
“There are a lot of mixed emotions among the operators. They’re sad to see the X-326 being shut down,” Hutchison said. “There’s a lot of activity to support operations.”
When it was time to shut the cell down, Operator Russ Nickell verified personnel were in place on the cell floor and in the local control center. Watching the instrument panel, a small crowd waited for needles on the gauges to reach zero before Nickell pushed the “Motor Stop” button and motors on the cell floor came to a slow halt.
“That’s it. Lights are out. We’re done,” Nickell said.
The enriched uranium was originally used by the Defense Department. Later operations produced fuel for the U.S. Navy and civilian power plants.
The first cells of the cascade were brought online in 1954. Preparations for the shutdown began in January after completion of a cleanup and treatment program on the equipment. The last cell was one of the high-speed cells used to separate uranium from the lighter gasses.
Over the lifetime of the cascade, more than 1 billion pounds of uranium was processed, filling nearly 40,000 14-ton cylinders. The cascade was placed in “cold standby” status in 2001 in the wake of newer technologies and changes in market demand for enriched uranium.
The plant was placed in “cold shutdown” in 2005 as the Department of Energy began to plan for decontamination, decommissioning, and site cleanup. Fluor-B&W Portsmouth assumed cleanup contractor duties for the Department of Energy in March 2011.