GAO Report on NNSA Nuclear Weapons Infrastructure Projects

GAO Reports & Testimonies

Published February 26th, 2026

Detected February 27th, 2026

Summary

A GAO report released February 26, 2026, highlights significant cost overruns and delays in the National Nuclear Security Administration's (NNSA) major construction projects. The report indicates cumulative cost overruns have risen to $4.8 billion and delays to 30 years as of June 2025, impacting the modernization of nuclear weapons infrastructure.

View original document View source feed page

What changed

The Government Accountability Office (GAO) has released a report detailing substantial cost overruns and schedule delays in the National Nuclear Security Administration's (NNSA) major construction projects. As of June 2025, cumulative cost overruns for NNSA's portfolio of major projects in the execution phase have increased to $4.8 billion, up from $2.1 billion in 2023, with cumulative schedule delays reaching 30 years, an increase from 9 years. Two specific projects, the Uranium Processing Facility (UPF) Main Process Building and UPF Salvage and Accountability Building, account for a significant portion of these overruns and delays. Contributing factors include inadequate project management by contractors, poor vendor performance, and increased material costs.

This report serves as a biennial assessment of NNSA's progress on its critical infrastructure modernization efforts supporting the nation's nuclear weapons stockpile. While NNSA has addressed many prior recommendations, eight remain open. Regulated entities, particularly those involved in government contracting or oversight of large-scale federal projects, should note the persistent challenges in project management and cost control highlighted by the GAO. The report underscores the need for enhanced oversight and management practices to mitigate future cost growth and delays in these high-risk projects.

What to do next

Review GAO report GAO-26-107777 for insights into project management challenges.
Assess internal project management and oversight practices for large-scale infrastructure initiatives.
Monitor NNSA's progress on addressing the eight open GAO recommendations.

Source document (simplified)

GAO-26-107777 Published: Feb 26, 2026. Publicly Released: Feb 26, 2026.

Fast Facts

The National Nuclear Security Administration is overseeing more than $30 billion in major construction projects to modernize the research and production infrastructure supporting the nation's nuclear weapons stockpile—a High Risk List item. This is our second biennial assessment of NNSA's progress.

NNSA's major construction cost overruns grew since our last assessment in 2023 —rising from $2.1 billion to $4.8 billion. And delays have grown, too, from 9 years to 30 years, as of June 2025. Management, vendor, and input costs all contributed to cost growth and delays.

NNSA has implemented many of our prior recommendations but 8 remain open.

Rendering of Pantex Plant's High Explosives Science and Engineering Facility, Which is Being Built in Amarillo, TX

Artists' rendering of a nuclear research facility with two large, flat buildings and a paved area in the shape of a cartoon atom

Highlights

What GAO Found

The National Nuclear Security Administration (NNSA) is overseeing the design or construction of 28 major construction projects—each estimated to cost $100 million or more—that collectively are estimated to cost more than $30 billion.

Since GAO’s 2023 report, cumulative cost and schedule overruns have increased for NNSA’s portfolio of major projects in the execution phase (which have approved cost and schedule baselines). Specifically, as of June 2025, NNSA’s cumulative cost overrun for the portfolio had increased from $2.1 billion in 2023 to $4.8 billion, and the cumulative schedule delay increased from 9 years to 30 years (see figure).

Cumulative Cost and Schedule Overruns for NNSA’s Portfolio of Major Projects in Execution Phase, 2023–2025

Two of NNSA’s 16 major projects in the execution phase—the Uranium Processing Facility (UPF) Main Process Building and UPF Salvage and Accountability Building at the Y-12 National Security Complex—are responsible for about 80 percent of the cumulative cost overrun and 40 percent of the cumulative schedule delay. However, seven other major projects in this phase have incurred or expect to incur a cost overrun of more than 20 percent compared with their originally approved cost baselines.

According to NNSA documents and officials, cost or schedule overruns for major projects in the execution phase were often associated with inadequate project management by NNSA’s management and operating (M&O) contractors; poor performance by vendors or subcontractors overseen by M&O contractors; or increased costs of equipment, materials, or vendors.

Of the 12 NNSA major projects in the definition phase (which do not yet have cost and schedule baselines),

eight are either on hold, implementing design changes, experiencing design challenges, or assessing the effect of these issues on their cost and schedule estimates; and
four have identified critical technologies and have met milestones for maturing these technologies, according to project documents and officials.

Why GAO Did This Study

NNSA—a separately organized agency within the Department of Energy (DOE)—plans to invest tens of billions of dollars in major construction projects to modernize the research and production infrastructure supporting the nuclear weapons stockpile.

Senate Report 117-130, accompanying a bill for the National Defense Authorization Act for Fiscal Year 2023, includes a provision for GAO to review NNSA’s major projects on a biennial basis. GAO assessed (1) the performance of NNSA’s portfolio of major projects in the execution phase, and (2) the development and maturity of project designs and critical technologies for projects in the definition phase. This report also includes summaries of NNSA’s 28 major projects.

GAO collected and analyzed data on NNSA’s 28 major projects and interviewed officials. GAO analyzed information on cost and schedule performance for 16 projects in the execution phase. GAO also collected information on the status of design and technology maturity for 12 projects in the definition phase. GAO’s review excluded major projects that did not have approved preliminary cost and schedule estimates or were not subject to certain DOE acquisition requirements.

Recommendations

In prior work, GAO made multiple recommendations to improve NNSA’s management of its major projects. NNSA agreed with most of those recommendations and has implemented many changes. However, as of December 2025, NNSA had not fully addressed eight of the 21 recommendations.

Full Report

Highlights Page (1 page)

Full Report (96 pages)

GAO Contacts

Allison Bawden Director Natural Resources and Environment bawdena@gao.gov

Media Inquiries

Sarah Kaczmarek Managing Director Office of Public Affairs media@gao.gov

Public Inquiries

Topics

Energy Cost and schedule Nuclear security Plutonium Contractor performance Construction Project milestones Critical technologies Project management National security Cost estimates