There are at least 500 too few employees at the Y-12 National Security Complex in Oak Ridge, Tenn., which has contributed to a cost increase and schedule slip for the uranium processing facility under construction there, the Secretary of Energy testified in Congress Thursday.

In its budget request for fiscal year 2024, the National Nuclear Security Administration (NNSA), part of the Department of Energy, said the Uranium Processing Facility (UPF) would cost between $8.5 billion and $8.95 billion to complete. That’s up from a previous estimated project cost of $6.5 billion and a construction-complete date of Dec. 31, 2025 at the latest. The agency acknowledged last year that UPF wouldn’t make those goals.

The new complex for producing the secondary stages of thermonuclear weapons should now be done some time between December 2028 and March 2029, according to the request. 

“There is an estimated delay associated with that,” Secretary of Energy Jennifer Granholm told the House Appropriations energy and water development subcommittee. “Part of the challenge, as is every business in the country, is that we are experiencing a labor challenge. For example, we have approximately 3,000 people on site every day. We need 3,500 and that has caused delays.” 

Delays in the project timeline in turn cause supply chain “crunches,” she added. The budget request says NNSA has had difficulty attracting qualified engineering staff and has only about 75 percent of the planned amount on its payroll. That created “the need to offer incentives and is lengthening design time, increasing indirect costs,” according to the request. 

Rebaselining the program took into account the need for more staff and built in margin for potential future delays, Granholm said. NNSA requested $760 million for UPF for fiscal year 2024, which begins Oct. 1.

“The new estimates contain significant margin and contingency allowances and they are based on labor productivity that has now been measured up, so procurements are complete,” she said. “We’re past the initial supply chain crunches that were plaguing us before. This [budget] meets those requirements.”

A version of this story first appeared in Defense Daily affiliate publication Nuclear Security & Deterrence Monitor.