The Houdaille-Hershey Plant was a secret Manhattan Project site located in Decatur, Illinois that was responsible for plating the interior of pipes with a nickel-powder barrier material that could be used for the gaseous diffusion process for the enrichment of uranium.
Continuing failure to develop a suitable barrier material for the gaseous diffusion process by 1943 led to a renewed sense of urgency to develop an adequate material that could withstand the high pressure of the heavy, corrosive gas used in the process.
By January 1943, interior-decorator Edward Norris and chemist Edward Adler had perfected an electro-deposited nickel mesh barrier that seemed promising. With the gaseous diffusion process dead in the water, Groves authorized full-scale production of the “Norris-Adler” barrier with the hope that this new material would revive the failing process. The Houdaille-Hershey Corporation took on the assignment on April 1, 1943 and began planning a new factory for the purpose in Decatur, Illinois.
In the fall of 1943, operating contractor Kellex succeeded in developing another promising barrier material—one that combined the best features of the Norris-Adler barrier and the compressed nickel-powder barrier. The problem then was what to do with the Houdaille-Hershey plant already under construction which was specifically designed to produce the Norris-Adler barrier.
Kellex wanted to strip the Houdaille-Hershey Plant and convert it, preferring a delay in the operation of K-25 to the risk of failure. Harold Urey argued that abandoning the Norris-Adler barrier would mean forgoing the production of U-235 by gaseous diffusion in time to shorten the war.
In January 1944, Groves decided to switch over to the new, superior barrier. The Houdaille-Hershey plant was stripped and reequipped to produce the new material.
Workers at the plant were tasked with nickel-plating all the pipe interiors, a difficult new process accomplished by filling the pipes themselves with a plating solution and rotating them as the plating current did its work.