For thousands of years, tunnels have been built to connect people to places that were previously inconvenient or unreachable. These engineering marvels provide a conduit for transporting goods and commodities efficiently. The Uranium Processing Facility Project recently achieved a historic milestone that connects Y‑12’s past to the future: the Highly Enriched Uranium Materials Facility Connector tunnel is now “in the dry,” with the last concrete placement for the roof completed. Equipment for critical systems that will be used during operating conditions, such as roll‑up doors, ventilation systems, fire protection and detection, and emergency notification systems, can now be installed, bringing UPF one step closer to construction completion.
“With the completion of HCON, we have finished UPF’s last structural skyline change at Y‑12,” said UPF HCON Yard Area Manager Chris P. “UPF’s building lines are now complete, and will be seen by everyone at Y‑12 for decades to come. It has been an honor to work with the team of craft professionals, UPF professional staff, and CNS Safeguards and Security that continue to deliver the mission through safe performance and first‑time quality.”
The construction of HCON was an impressive undertaking, requiring massive amounts of materials and manpower to reach this most recent milestone. With 4,900 cubic yards of concrete, 22 tons of reinforcing steel, and more than 37,000 hours of work, the HCON team — comprised of laborers, iron workers, cement masons, operators, electricians, pipefitters, and carpenters — safely completed the tunnel 10 months ahead of schedule, cementing its place in Y‑12 history.
Due to the teamwork and advanced coordination between UPF Construction and Y‑12 Safeguards and Security, and the oversight provided by the NNSA Y‑12 Project Management Office, the ahead‑of‑schedule completion of the tunnel’s construction also supports completing the UPF portion of the Perimeter Intrusion Detection and Alert System by the end of 2026. HEUMF is currently within PIDAS, while UPF is outside of it.
“The UPF Security Support team, CNS Physical Security, Construction, and PMO worked in lockstep to overcome many unique challenges to achieve this significant achievement,” said UPF Security Manager Chris M. The efforts of this collaboration saved thousands of additional Construction and Protective Force hours and had a direct impact on the early completion of HCON. The HCON connection extends beyond the physical structure. It sets the stage for a new era of efficiency, and has fostered collaboration among diverse groups working together to achieve timely delivery to the nation.
