Elodie Collins 
United Cleanup of Oak Ridge, an Amentum-led partnership with Honeywell that works to deactivate and demolish former nuclear facilities, has named Jim Blankenhorn as president and CEO, effective April 1, 2026. Blankenhorn will succeed Ken Rueter, who will retire on March 30, 2026, UCOR said Tuesday.
Who Is UCOR’s New CEO?
Blankenhorn currently serves as senior vice president of Amentum’s Energy & Environment North America business, which offers nuclear management remediation, nonproliferation and other related services to the Department of Energy, the National Nuclear Security Administration and the Department of War.
Prior to his current role, he led as president of Amentum Technical Services. He also held the positions of the company’s lead executive for the Nuclear Operations and Cleanup Sector and as recovery manager, deputy project manager and chief operating officer at the Amentum-led Nuclear Waste Partnership.
His experience in the DOE Environmental Management industry is extensive. He was involved in the Waste Disposition Project at the Los Alamos National Laboratory and the DOE Mixed Waste Focus Area and worked at the Savannah River Site.
Blankenhorn’s career also includes service in the U.S. Army as a brigadier general who has led concept development, training, staffing, and doctrine development for Chemical, Biological, Radiological and Nuclear Forces, consequence management operations, and defense support to civilian agencies. He has been awarded the Legion of Merit, the Meritorious Service Medal, and the Army Commendation Medal.
Who Is Ken Rueter?
Rueter has led UCOR for over a decade. Under his leadership, the company secured a $4.1 billion contract to demolish the old K-25 Gaseous Diffusion Plant and an $8 billion contract to clean up soil and groundwater contamination.
“Together, we have safely delivered on one of the Department of Energy’s most complex cleanup missions, often ahead of schedule and under budget ‒ while setting new standards for safety, productivity, risk reduction, innovation and community impact,” Reuter said in his message to UCOR staffers. “This has not been an easy decision because serving alongside you has been one of the greatest honors of my career.”
Rueter will continue to serve UCOR in a part-time capacity as executive board director starting April 1.
