A new U.S. Government Accountability Office assessment of construction projects managed by the National Nuclear Security Administration finds that cost overruns and schedule delays at several defense nuclear modernization facilities have more than doubled since 2023.
The Feb. 27 report updates GAO’s oversight of the agency’s construction projects and compares current performance to a 2023 review of its nuclear weapons infrastructure modernization program.
GAO found that cumulative cost growth for key agency construction efforts increased from about $2.1 billion in 2023 to about $4.8 billion in June 2025.
The agency’s capital program includes new and replacement facilities that support uranium processing and plutonium pit manufacturing. It manages 28 major construction projects valued at more than $100 million each, representing a portfolio of at least $30 billion, GAO said. Sixteen are under construction, with 12 in design or early planning.
Within that portfolio, GAO found 17 projects facing challenges, including delays, redesigns, cost overruns or suspensions. They are expected to eventually exceed their approved budgets by at least 20%.
Timetable pressures are also increasing. The GAO said some projects initially expected to take about nine years could take up to 30 years from approval to completion.
Main projects under analysis
Congressional staff overseeing the agency say the problems reflect deeper structural problems beyond any single project.
Looking for quick answers on construction and engineering topics?
Try Ask ENR, our new intelligent AI search tool.
Ask ENR →
According to GAO’s analysis, accumulated cost overruns and schedule delays in NNSA’s large construction project portfolio have increased substantially since 2023.
Chart courtesy of GAO
“Every project that NNSA has on the construction side has been over budget and way behind schedule,” House Armed Services Committee staffers familiar with the portfolio, who were not authorized to speak publicly, told ENR.
“The reality is these buildings are old,” the employees said. “These facilities are old. Many administrations since the 1970s have not really prioritized the facilities, and now many of them are at the point of failure.”
GAO attributes much of the problem to weaknesses in early cost forecasting and project management, along with contractor oversight issues due to NNSA’s reliance on the contractor model of management and operation.
Committee staff said the findings reflect concerns raised during congressional oversight.
“If a building is going to cost $6 billion, it’s going to cost $6 billion,” one staffer said. “The problem is that historically NNSA has come in and said it’s going to cost $1.2 billion and it’s going to take six years. I don’t think they have the expertise on their side to fully scope these big projects.”
Two projects account for most of the cost growth identified in the report: the uranium processing facility at the Y-12 National Security Complex in Oak Ridge, Tennessee, and plutonium-related construction at the Savannah River site near Aiken, SC.
”
If a building is going to cost $6 billion, it’s going to cost $6 billion. The problem is that NNSA has historically said it would cost $1.2 billion and take six years.
— Staff member of the House Armed Services Committee
The uranium processing facility is designed to replace the old uranium component production buildings and consolidate operations into a new secure complex at Y-12. The site is managed for the federal agency by Consolidated Nuclear Security LLC, while Bechtel National Inc. serves as the prime construction contractor for the project.
GAO said the project’s core process construction cost increased from about $4.7 billion to about $7.45 billion, with completion expected in January 2032 instead of December 2025. The Uranium Processing Facility Recovery and Accountability Building also increased its baseline from about $1.18 billion to $2.25 billion. dollars with the same delay.
In 2019, ENR reported that a federal court ruling required the U.S. Department of Energy to reconsider parts of the uranium processing facility’s scope after environmental groups challenged the agency’s approach to replacing aging uranium processing operations at the Y-12 complex.
The facility was estimated to cost about $6.5 billion at the time.
At the Savannah River site, NNSA is developing new plutonium processing facilities to support expanded pit production. The site is operated by Savannah River Nuclear Solutions LLC, a consortium led by Fluor Corp. and Newport News Nuclear Inc.
The facility is part of a federal push to restore domestic plutonium pit production capacity needed to support the long-term modernization of nuclear weapons.
GAO said construction of the main process for this effort is now expected to cost more than $22 billion, with completion expected by September 2035.
Congressional staff said those projects remain a central focus for oversight.
“I would put Savannah River on that list and the uranium processing facility,” said one committee member. “Those are the big two. The uranium processing facility is much further along, so the possibility of this ballooning further is limited. But there are still a lot of questions around the Savannah River.”
RELATED
The court ruling affects the scope of the $6.5 million uranium processing project
Nuclear weapons infrastructure presents unusual construction challenges given the need to meet strict safety, security and environmental standards related to the handling of weapons-grade nuclear material.
Those requirements can dramatically increase costs, congressional staffers said.
“The costs are like four- to six-tuple if you’re inside the fence line compared to outside,” said one staffer, referring to highly secure Category 1 nuclear facilities where special nuclear material is processed or stored.
GAO said these facilities require heavy shielding, specialized security systems and extensive security infrastructure, engineering requirements that can be difficult to capture in early cost estimates.
Committee staff also pointed to post-pandemic inflationary pressure, which has driven up steel and concrete prices in federal construction programs.
The report notes that the agency has implemented several corrective actions in recent years to strengthen cost estimating and project management practices following previous cost overruns at the uranium processing facility. However, GAO said additional improvements are still needed.
RELATED
DOE Cancels Disputed $28 Billion Nuclear Site Award to Fluor-Amentum
In response to ENR’s questions about project management issues raised in the GAO report, including construction at Los Alamos National Laboratory, an NNSA staff member directed ENR to the recent GAO assessment.
Congressional staffers said lawmakers still support the modernization effort despite those challenges.
“If the United States wants to maintain a nuclear deterrent, we have to invest in these facilities,” one staffer said. “But the way the program has been managed clearly raises concerns.”
