OAK RIDGE, TN - Y-12 National Security Complex recently completed efforts to downgrade Building 9206 from the status of nuclear facility to radiologically contaminated, an improvement milestone that reflects significantly reduced risk and moves the building a step closer to eventual demolition.

Pink fixative covers much of the abandoned equipment in 9206. The fixative is put on the equipment to encapsulate any remaining contamination. image by DOE

Building 9206 was shut down in 1994 with a significant inventory of uranium-bearing materials and contaminated equipment left behind. Because the building contained nuclear materials, it had to be monitored and managed.

“Our goal was to deactivate and downgrade Building 9206 by the end of 2025 to reduce nuclear criticality safety risk, free up valuable resources, and apply lessons learned to efforts in other production buildings,” said Building Transition Strategy Program Manager Anita Hazelwood.

Building 9206 was constructed in 1944 and served as a sister facility to another production building, with historical missions including chemical recycling, charge preparation, highly enriched and depleted uranium recovery and processing, and processing for the beta stage of the electromagnetic separation plant, also known as beta calutrons.

Building 9206 played a valuable role in both the Manhattan Project and the Cold War by processing special nuclear material. image by DOE

Efforts to remove the nuclear materials from Building 9206 began in 1994. De-inventory and decontamination were conducted intermittently until 2015 as part of various initiatives using different funding sources, but there was no clear deactivation and downgrade strategy.

In 2015, the Transition Strategy program received funding to downgrade the facility with two primary drivers: generating lessons learned before deactivating/downgrading other production buildings, and removing material from Building 9206 that would need to be processed through another production building prior to its shutdown.

The following actions had to be completed to satisfy the program goals:

• Draining fissile solutions,
• Removing holdup or components mechanically/physically,
• isolating system/components to prevent water ingress and/or applying fixative to isolate and prevent movement of residual holdup, and
• completing a final nondestructive assay evaluation in support of downgrade and turnover.

The team developed lessons learned for deactivation/decontamination of future buildings. These lessons included developing a nuclear criticality safety downgrade strategy, allotting dedicated resources for key disciplines, and conducting long-term facility maintenance.

Downgrading Building 9206 was completed on time at a cost of approximately $60 million, which was far below the original estimate of $160 million. Clearing this facility of enriched uranium and fissile materials took a significant effort, including disconnecting and draining process equipment and miles of piping.

Now that the downgrade is complete, the building will transfer to Y-12’s Legacy Facility Stewardship program for management. They will ensure the facility remains in a safe configuration until the U.S. Department of Energy Office of Environmental Management beginsdemolition work in the future.