Energy and Water Development Appropriations for Nuclear Weapons Activities: In Brief

Contents

• Introduction
• NNSA's Weapons Activities Account
• FY2026 Budget Request
• FY2025 Budget Request
• Selected Major Programs for FY2025
• Stockpile Management
• Production Modernization
• Stockpile Research, Technology, and Engineering
• Infrastructure and Operations
• Selected Legislative Activity
• FY2025 Appropriations
• FY2025 Authorizations
• FY2024 Appropriations
• FY2024 Authorizations
• Potential Issues for Congress

Introduction

Responsibility for U.S. nuclear weapons resides with both the U.S. Department of Defense (DOD) and the U.S. Department of Energy (DOE). DOD develops, deploys, and operates the missiles and aircraft that can deliver nuclear warheads. Based on presidential guidance, DOD also generates military requirements for the warheads carried on those platforms. The National Nuclear Security Administration (NNSA), a semiautonomous agency within the DOE, oversees the research, development, test, and acquisition programs that produce, maintain, and sustain the warheads.¹ NNSA partners with DOD through the congressionally established Nuclear Weapons Council (NWC) to coordinate the nuclear weapons work between the two departments. The NWC is also responsible for the annual certification of NNSA's budget request.²

NNSA is also responsible for storing and securing undeployed warheads that are not deployed and for dismantling warheads that have been retired and removed from the stockpile. NNSA manages and sets policy for the U.S. nuclear weapons complex, consisting of eight sites in seven states. These sites include three laboratories (Los Alamos National Laboratory, NM; Lawrence Livermore National Laboratory, CA; and Sandia National Laboratories, NM and CA); four production sites (Kansas City Plant, MO; Pantex Plant, TX; Savannah River Site, SC; and Y-12 National Security Complex, TN); and the Nevada National Security Site (formerly Nevada Test Site).³ (For additional information on NNSA and its sites, see CRS Report R48194, The U.S. Nuclear Security Enterprise: Background and Possible Issues for Congress.)

Congress authorizes funding for DOD and NNSA nuclear weapons activities in the annual National Defense Authorization Act (NDAA) and provides funding for the NNSA through the Energy and Water Development Appropriations Act. (For an overview of the Energy and Water Development Appropriations Act, see CRS Report R48097, Energy and Water Development: FY2025 Appropriations.)

NNSA operates three programs, each of which receives funding in a dedicated appropriation account: Defense Nuclear Nonproliferation, Naval Reactors, and Weapons Activities. The Weapons Activities account is the subject of this report. This account supports U.S. nuclear warheads and associated components, provides the materials and components for those weapons, and sustains and modernizes the infrastructure that supports these missions.

NNSA's Weapons Activities Account

FY2026 Budget Request

According to Office of Management and Budget documentation released on May 2, 2025, NNSA's budget request for FY2026 is $30.0 billion, which includes $6.0 billion in Congressional Reconciliation resources.⁴ According to a more detailed May 30, 2025, DOE "budget in brief" document for FY2026, the Weapons Activities account request is $24.9 billion, $5.6 billion (29%) more than the enacted funding of $19.3 billion in FY2025, out of the $30.0 billion budget request.⁵ This Weapons Activities request amount includes $4.8 billion in "mandatory Reconciliation resources," the DOE "budget in brief" states.

FY2025 Budget Request

In its FY2025 budget request, NNSA notes that the "overarching mission" for Weapons Activities is to "deliver warheads that meet military requirements." As required by Congress, the FY2025 budget request lists the following NNSA integrated priorities for weapons activities:⁶

• Support the active stockpile.
• Execute warhead modernization programs.
• Reestablish and modernize production infrastructure and capabilities.
• Plutonium pit production.
• Modernization and production programs for other materials and components.
• Develop and sustain strong science, technology, and engineering efforts to support the stockpile and the design, assessment, and certification infrastructure which underpin the deterrent.
• Continue assessing concepts to meet future threats.
• Address gaps in experimental and computational capabilities.
• Hire and retain the workforce necessary to achieve deliverables and address retirements.
• Secure transport of nuclear materials and warheads.
• Uphold strong proactive maintenance and recapitalization programs.
• Implement physical security systems and measures across the complex.
• Sustain and improve information technology systems and cybersecurity to meet. directives and other requirements.

Selected Major Programs for FY2025

NNSA's budget request for FY2025 seeks $19.8 billion for Weapons Activities, $740.6 million (3.9%) more than the enacted funding of $19.11 billion in FY2024,⁷ within a total budget of $25 billion for NNSA.⁸ The FY2025 request contains funding to continue NNSA's nuclear warhead modernization programs and to modernize NNSA production and research facilities, as well as funding to support future plutonium pit production at the Savannah River Site and Los Alamos National Laboratory. The Weapons Activities appropriation is organized into four main mission areas, after being reorganized and renamed in FY2021. These programs, each with a request of over $3 billion for FY2025, include the following:

• Stockpile Management. The budget requested $188 million (-3.5%) less funding for FY2025 than was enacted in FY2024 to support work on nuclear warhead life extension programs, warhead surveillance and quality assurance, maintenance, and related activities.
• Production Modernization. The budget requested $11 million (0.2%) more funding for FY2025 than was enacted in FY2024 for programs that focus on maintaining and expanding the production capabilities for nuclear weapons components critical to weapons performance.⁹
• Stockpile Research, Technology, and Engineering. The budget requested $106 million (-3.2%) less funding for FY2025 than was enacted in FY2024 for programs that provide the scientific foundation for the current and future stockpile. This category replaces the Research, Development, Test and Evaluation program area.
• Infrastructure and Operations (I&O). The budget requested $715 million (27.7%) more funding for FY2025 than was enacted in FY2024 for programs to maintain, operate, and modernize NNSA's infrastructure. This category is intended to support construction of new facilities and also fund deferred maintenance in older facilities.

In addition to these activities, the NNSA also requested in the budget a total of $195 million (9%) more funding for FY2025 than was enacted in FY2024 for several other programs, such as the Secure Transportation Asset, Defense Nuclear Security, Information Technology and Cybersecurity, and Legacy Contractor Pensions (see Table 1).

The outyear funding requests provided in the FY2025 budget requests anticipate further steady growth of the Weapons Activities account, potentially from $20.6 billion in FY2026 to $22.4 billion in FY2029.¹⁰ Then-NNSA Administrator Jill Hruby stated in a 2024 speech that "NNSA is being asked to do more than at any time since the Manhattan Project."¹¹ In a separate speech, she emphasized that the U.S. nuclear security enterprise will require further "increased investment," including to avoid delays in implementing the current program of record through the mid-2030s as well as to "avoid failure, because we are pushing all the limits of our infrastructure."¹²

Stockpile Management

According to NNSA's FY2025 budget materials, the Stockpile Management requirements "maintain a safe, secure, reliable and effective nuclear weapons stockpile."¹³ The activities in this program area include warhead life extension, modification, and design efforts; the annual assessment process for the current active stockpile; stockpile sustainment activities; warhead dismantlement activities; and sustainment of manufacturing capabilities and capacities. The Stockpile Management program includes five subprograms:

• Stockpile Major Modernization: includes continuing activities for the B61-12 Life Extension Program (LEP), W88 Alteration (ALT) 370, W80-4 LEP, W87-1 Modification program, and a feasibility study for the W93 program. The FY2025 budget request also includes development and production engineering activities for the B61-13 program. The budget request further notes that, "while a dedicated line item for the Sea Launched Cruise Missile (SLCM) is not currently included in the FY 2025 request, NNSA is proposing $1,165 [million] for the W80‐4 warhead which the NDAA associates with SLCM‐N."¹⁴
• Stockpile Sustainment: includes activities to maintain and develop each Stockpile System and Multi-Weapons System. According to NNSA, Stockpile Sustainment executes "maintenance, surveillance, assessment, surety, management activities, and support of weapons until they are dismantled for all enduring weapons systems in the stockpile."¹⁵ The program includes the B61, W76, W78, W80, B83, W87, and W88 Stockpile Systems, and Multi-Weapon Systems.¹⁶
• Weapons Dismantlement and Disposition (WDD): includes funding for the interim storage of warheads awaiting dismantlement, funding for actual dismantlement, and funding for the disposition of warhead components and materials.
• Production Operations (PO): sustains manufacturing capabilities and capacities, including weapons assembly and disassembly, component production, surveillance, and weapon safety and reliability testing.
• Nuclear Enterprise Assurance (NEA): a program introduced in FY2023, NEA "actively manages subversion risks to the nuclear weapons stockpile and associated design, production, and testing capabilities."¹⁷

Table 2 provides data on weapons activities by warhead program.¹⁸

Production Modernization

According to NNSA's FY2025 budget materials, the Production Modernization program is tasked with "modernizing the facilities, infrastructure, and equipment that produce materials and components to meet stockpile requirements and maintain the Nation's nuclear deterrent."¹⁹ The highest spending category in NNSA's FY2025 budget request, the Production Modernization program includes six subprograms:

• Primary Capability Modernization: includes plutonium pit modernization and high explosives and energetics modernization. In its FY2025 budget request, NNSA notes that the increase supports plutonium pit production at Los Alamos National Laboratory. NNSA states that the agency "remains committed to achieving the pit production capability goals on the path to 80 [pits per year]" and will provide congressional with quarterly briefings on pit production.²⁰
• Secondary Capability Modernization: includes uranium modernization, depleted uranium modernization, and lithium modernization. This category's budget primarily request reflects increased investment in a variety of operations at the Y-12 facility.²¹
• Tritium Modernization and Domestic Uranium Enrichment: the Tritium Modernization portion of this program funds activities needed to produce, recover, and recycle the tritium gas used in U.S. nuclear weapons, while the Domestic Uranium Enrichment Program is designed to ensure a reliable supply of enriched uranium to support U.S. national security and nonproliferation needs. The budget increase is due to "needs for labor and material purchases" as well as the initiation of design activities for the Domestic Uranium Enrichment program.²²
• Non-Nuclear Capability Modernization: according to NNSA, this program area funds capabilities necessary for the "design, qualification, production, and surveillance" of non-nuclear components for multiple weapon systems.²³ The budget increase is for the expansion of efforts at the Kansas City plant and the modernization of capabilities at Sandia National Labs.²⁴
• Capability Based Investments: according to NNSA, this program "modernizes scientific and manufacturing capabilities that have degraded due to aging, broken, or outdated equipment and supporting systems."²⁵
• Warhead Assembly Modernization: this program, new in FY2025, is for modernizing capabilities associated with the assembly and disassembly of warheads at the Pantex plant.²⁶

Stockpile Research, Technology, and Engineering

According to NNSA's FY2025 budget materials, the Stockpile Research, Technology, and Engineering program "provides the knowledge and expertise needed to maintain confidence in the nuclear stockpile without additional nuclear explosive testing."²⁷ The program funds not only science and engineering programs, but also large experimental facilities, such as the Enhanced Capabilities for Subcritical Experiments (ECSE) program at the Nevada National Security Site (NNSS), and NNSA's first Exascale high performance computing system at Livermore Laboratory.²⁸ The Stockpile Research, Technology, and Engineering program includes five subprograms:

• Assessment Science: this program area performs experiments to obtain the materials and nuclear data required to validate and understand the physics of nuclear weapons performance, and conducts activities that develop, exercise, and maintain the expertise of NNSA's nuclear weapon design, engineering, and assessment community.²⁹
• Engineering and Integrated Assessments: this program area aims to ensure that current and future nuclear weapons systems are survivable and adaptable. It includes developing advanced weapons capabilities as well as certification and qualification capabilities.³⁰
• Inertial Confinement Fusion: this program area focuses on High Energy Density (HED) science capability development for nuclear weapons applications. It includes funding for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory.³¹
• Advanced Simulation and Computing: this program area supports stockpile stewardship with advanced modeling and computing capabilities to help maintain confidence in the nuclear stockpile without underground explosive testing.³²
• Weapon Technology and Manufacturing Maturation: according to NNSA budget documents, this program area provides "agile, affordable, assured, and responsive technologies and capabilities for nuclear stockpile sustainment and modernization."³³

Infrastructure and Operations

According to NNSA budget materials, the Infrastructure and Operations Program "maintains, operates, and modernizes NNSA's infrastructure," which includes planning and constructing all NNSA support facilities except for complex-construction projects (which are funded by that specific capability sponsor).³⁴ Major changes in the FY2025 budget request include increased funding for the production of plutonium pits and for the expansion of capacity at the Kansas City facility, as well as for projects at the Savannah River Site.³⁵

Selected Legislative Activity

FY2025 Appropriations

NNSA's budget request for FY2025 seeks $19.85 billion for Weapons Activities, $740 million (3.9%) more than the enacted funding of $19.11 billion in FY2024. The House of Representatives Committee on Appropriations-reported FY2025 Energy and Water Development and Related Agencies Appropriations Act (H.R. 8997) provides $20.34 billion for Weapons Activities, which is $490 million over the NNSA request. The Senate Committee on Appropriations-reported FY2025 Energy and Water Development and Related Agencies Appropriations Act (S. 4927) provides $19.93 billion for Weapons Activities, which is $81 million over the NNSA request.³⁶

On March 15, 2025, President Trump signed the Full-Year Continuing Appropriations and Extensions Act, 2025 (P.L. 119-4), which funded the Weapons Activities account at $19.293 billion, which is $556 million less than the FY2025 request (-3%) but $185 million (1%) more than the FY2024 enacted level.³⁷ The American Relief Act, 2025 (P.L. 118-158) provided an additional $2 million under the Weapons Activities account to mitigate damage caused by Hurricanes Helene and Milton.³⁸

FY2025 Authorizations

The House of Representatives-passed FY2025 National Defense Authorization Act (NDAA) (H.R. 8070) authorizes $19.98 billion for Weapons Activities, which is $127 million over the NNSA request. The Senate Armed Services Committee-reported FY2025 NDAA (S. 4638) authorizes $19.90 billion for Weapons Activities, which is $51 million over the NNSA request. The conference FY2025 NDAA (P.L. 118-159) authorizes $19.98 billion for Weapons Activities, $132 million over the FY2025 request.

FY2024 Appropriations

NNSA's budget request for FY2024 sought $18.83 billion for Weapons Activities, $1.72 billion (10.0%) more than the enacted funding of $17.12 billion in FY2023. The Energy and Water Development and Related Agencies Appropriations Act, 2024 (P.L. 118-42), provided $19.108 billion for NNSA Weapons Activities—$275 million (1.4%) more than the requested amount (see Table 4).

FY2024 Authorizations

The National Defense Authorization Act for Fiscal Year 2024 (NDAA; P.L. 118-31) authorized $19.12 billion for NNSA Weapons Activities (see Table 5).

Potential Issues for Congress

Congressional oversight activities for the programs described above could include hearings, annual appropriations and authorizations, reporting requirements, or site visits. Members of Congress have previously expressed concerns about NNSA's ability to meet its goals, carry out capital infrastructure projects on time and within budget, and hire and retain contractor and federal staff in across the nuclear security enterprise. (For additional information, see CRS Report R48194, The U.S. Nuclear Security Enterprise: Background and Possible Issues for Congress.) Congress may continue to track progress on NNSA's ability to meet its program goals, particularly as part of the annual budget cycle hearings.

This report was originally authored by Alexandra Neenan, Analyst in U.S. Defense Infrastructure Policy, and Mary Beth Nikitin, Specialist in Nonproliferation.

Footnotes