Contents

• Introduction
• NNSA's FY2027 Budget Request
• Weapons Activities
• Defense Nuclear Nonproliferation
• Selected Legislative Activity
• FY2027 NNSA Budget Request: Summary of Congressional Action

Summary

The National Nuclear Security Administration (NNSA) is a semiautonomous agency within the U.S. Department of Energy (DOE). NNSA is responsible for maintaining the U.S. nuclear weapons stockpile, carrying out nuclear nonproliferation activities and nuclear and radiological emergency response, and providing nuclear reactors and fuel to the U.S. Navy. (For additional information on NNSA and its sites, see CRS Report R48194, The U.S. Nuclear Security Enterprise: Background and Possible Issues for Congress.)

For FY2027, NNSA requested $32.80 billion—$7.40 billion (29%) more than the FY2026 enacted discretionary amount of $25.40 billion. Of this, $27.44 billion was requested for programs related to development, production, certification, and maintenance of the U.S. nuclear warhead stockpile (i.e., the Weapons Activities account) and $2.39 billion for nuclear nonproliferation and nuclear counterterrorism (i.e., the Defense Nuclear Nonproliferation account). NNSA also requested $2.39 billion for the Naval Reactors program, carried out in collaboration with the U.S. Navy, and $577.10 million for NNSA federal salaries and expenses.

Congress generally authorizes funding for NNSA in an annual National Defense Authorization Act (NDAA) and provides funding for NNSA through an annual Energy and Water Development Appropriations Act. In authorizations and appropriations hearings for NNSA's FY2027 budget request, some Members have discussed oversight issues, such as proposed funding increases and warhead development activities in the Weapons Activities budget, NNSA's plutonium pit production strategy and costs, proposed cuts to the Defense Nuclear Nonproliferation budget and staff, costs and schedules of NNSA projects, NNSA's long-range plans to modernize infrastructure, NNSA's potential contributions to the monitoring and verification of Iran's nuclear capabilities, and U.S. policy on testing nuclear weapons. This report profiles NNSA's FY2027 budget request and tracks selected legislative activity.

Introduction

The National Nuclear Security Administration (NNSA) is a semiautonomous agency within the U.S. Department of Energy (DOE). NNSA is responsible for maintaining the U.S. nuclear weapons stockpile, carrying out nuclear nonproliferation activities and nuclear and radiological emergency response, and providing nuclear reactors and fuel to the U.S. Navy.¹

Congress generally authorizes funding for NNSA in an annual National Defense Authorization Act (NDAA) and appropriates funding for NNSA through an annual Energy and Water Development Appropriations Act. This report profiles NNSA's FY2027 budget request and tracks selected legislative activity.

NNSA's FY2027 Budget Request

In April 2026 congressional testimony, NNSA Administrator Brandon Williams stated that NNSA is "acting with urgency" to achieve its priorities,² which according to the NNSA's FY2027 budget request are to:

(1) maintain a safe, secure, and effective nuclear weapons stockpile;

(2) reduce global nuclear threats and keep nuclear and radiological materials or expertise out of the hands of terrorists and adversaries;

(3) provide safe and effective integrated nuclear propulsion systems for the United States (U.S.) Navy to ensure it remains an unmatched fighting force;

(4) strengthen key science, technology and engineering capabilities to support all missions; and

(5) modernize the Department of Energy (DOE)'s weapons production enterprise.³

For FY2027, NNSA requested $32.80 billion—$7.40 billion (29%) more than the FY2026 enacted discretionary amount of $25.40 billion.⁴ The FY2025 reconciliation law (P.L. 119-21), sometimes referred to as the One Big Beautiful Bill Act, provided an additional $3.89 billion for NNSA through FY2029. The budget request stated, "most of [this amount] will be obligated in FY2026."⁵ NNSA projected that its budget request would increase in the outyears, from $33.46 billion in FY2028 to $35.51 billion in FY2031.⁶

As detailed in Table 1, NNSA requested the following amounts for its four accounts:

• $27.44 billion for Weapons Activities focused on the development, production, certification, and maintenance of the U.S. nuclear warhead stockpile. This request would provide $7.03 billion (35%) more than the FY2026 enacted discretionary amount of $20.38 billion (see details below).
• $2.39 billion for Defense Nuclear Nonproliferation (DNN) programs focused on nuclear nonproliferation and counterterrorism. This request would provide $22.60 million (1%) more than the FY2026 enacted discretionary amount of $2.37 billion (see details below).
• $2.39 billion for Naval Reactors programs that design, develop, operate, maintain, and decommission the U.S. Navy's nuclear reactors and dispose of naval spent nuclear fuel.⁷ This request would provide $259.69 million (12%) more than the FY2026 enacted discretionary amount of $2.13 billion.
• $577.10 million for Federal Salaries and Expenses for a total of "1,992 [full-time equivalent staff] providing appropriate oversight to ensure NNSA can meet growing mission requirements and commitments."⁸ This request would provide $52.10 million (10%) more than the FY2026 enacted discretionary amount of $525.00 million.

Weapons Activities

As detailed in Table 2, the FY2027 Weapons Activities request is $27.44 billion, which would provide $7.06 billion (35%) more than the FY2026 enacted discretionary amount of $20.38 billion. P.L. 119-21 provided an additional $3.89 billion for NNSA, all for Weapons Activities, "most of which will be obligated in FY2026," according to the budget request.⁹ In testimony, NNSA Administrator Williams stated that NNSA is "urgently rebuilding America's nuclear weapons enterprise with agility and resilience to field a more diverse, flexible, and effective deterrent on a timeline that influences adversaries' decisions."¹⁰ The following selected programs are part of the Weapons Activities account:

• Stockpile Management, through which NNSA modernizes, sustains, and dismantles warheads in the U.S. nuclear stockpile. In FY2027, NNSA is executing "seven simultaneous warhead modernization programs" and plans to "authorize new future concept programs."¹¹
• Production Modernization, through which NNSA modernizes facilities and infrastructure involved in the production of materials and components for nuclear warheads. NNSA seeks the capacity to annually produce 80 plutonium pits for warheads "as close to 2030 as possible," as per congressional mandate in 10 U.S.C. §6128, and to continue the construction and refurbishment of a number of facilities, such as the Uranium Processing Facility in Tennessee.¹²
• Stockpile Research, Technology, and Engineering, through which NNSA "conducts weapons design, certification, and assessment activities," including subcritical testing and plutonium aging research, that "ensure confidence in the nuclear stockpile of today and tomorrow."¹³ The new Rapid and Advanced Capabilities subprogram, authorized in Section 3113 of the NDAA for Fiscal Year 2026 (P.L. 119-60), is "pursuing design, prototyping, and accelerated testing to deliver integrated and proven system concepts … for acquisition and fielding."¹⁴
• Infrastructure & Operations, through which NNSA "maintains, operates, and modernizes … infrastructure in a safe, secure, and cost-effective manner to support all NNSA programs."¹⁵

Defense Nuclear Nonproliferation

The DNN account consists of the Defense Nuclear Nonproliferation program (with several subprograms) and the Nuclear Counterterrorism and Incident Response (NCTIR) program.¹⁶ As detailed in Table 3, the FY2027 DNN request is $2.39 billion, which is $22.60 million (1%) more than the FY2026 enacted discretionary amount of $2.37 billion. Defense Nuclear Nonproliferation subprograms include

• Material Management and Minimization (M3) conducts global activities to reduce and, where possible, remove weapons-usable material (i.e., highly enriched uranium or plutonium) from civilian use.¹⁷ NNSA Administrator Williams has said that M3 plans to focus "on HALEU [high-assay low-enriched uranium] production, HEU [highly-enriched uranium] removals, and implementing executive order and legal requirements related to surplus plutonium management."¹⁸
• Global Material Security (GMS) works on international nuclear and radiological security and nuclear smuggling detection and deterrence. This subprogram has proposed funding decreases for FY2027 due to continued use of "additional FY 2026 enacted funding above the FY 2026 request level."¹⁹ According to NNSA, GMS is working to fulfill the congressional mandate of "eliminating the use of blood irradiation devices in the United States that rely on cesium chloride by December 31, 2027," per P.L. 115-232, §3141.²⁰
• Nonproliferation and Arms Control (NPAC) activities include technical support for civil nuclear agreement negotiations, reviewing export applications and technology transfer authorizations, and developing technologies for treaty verification and International Atomic Energy Agency (IAEA) safeguards, including the verification and monitoring of "Iranian nuclear capabilities (including impacts of [U.S. military operations in Iran, such as] Operations MIDNIGHT HAMMER and EPIC FURY)."²¹
• Defense Nuclear Nonproliferation Research and Development (DNN R&D) works on developing U.S. "capabilities to detect and characterize global nuclear threats," such as foreign nuclear material and weapons production, diversion of weapons-usable material, and nuclear detonations.²²
• The Nonproliferation Construction subprogram aimed to dispose of excess U.S. weapons plutonium through a "dilute and dispose" strategy until May 2025, when Executive Order 14302 halted the program.²³ The budget request did not include funding for Nonproliferation Construction in FY2027.

The NCTIR program evaluates nuclear and radiological threats and develops emergency preparedness plans. The Nuclear Emergency Support Team (NEST), which provides security for major events such as FIFA World Cup 2026, is part of the NCTIR.²⁴

Selected Legislative Activity

The Senate and the House of Representatives held hearings at which NNSA officials provided details on the FY2027 budget request, including²⁵

• an April 15, 2026, hearing of the House Committee on Appropriations, Subcommittee on Energy and Water Development and Related Agencies, in which some Members sought details on NNSA's plutonium pit production strategy and costs²⁶ and NNSA's spending plans for P.L. 119-21 funding;²⁷
• an April 20, 2026, hearing of the Senate Committee on Armed Services, Subcommittee on Strategic Forces, in which some Members sought details on proposed funding increases and warhead development activities in the Weapons Activities budget, NNSA's plutonium pit production strategy and costs, NNSA's potential contributions to U.S. efforts to denuclearize Iran, NNSA's spending plans for P.L. 119-21 funding, and NNSA's long-range plans to modernize infrastructure;²⁸
• an April 22, 2026, hearing of the House Committee on Armed Services, Subcommittee on Strategic Forces, in which some Members sought details on proposed funding increases and warhead development activities in the Weapons Activities budget, NNSA's plutonium pit production strategy and costs, and U.S. policy on testing nuclear weapons;²⁹
• an April 29, 2026, Senate Committee on Appropriations, Subcommittee on Energy and Water Development, in which some Members sought details on funding increases in the Weapons Activities budget, costs and schedules of NNSA projects, NNSA's spending plans for P.L. 119-21 funding, NNSA's plutonium pit production strategy and costs, cuts to DNN budget and staff, and NNSA's potential contributions to U.S. efforts to denuclearize Iran;³⁰ and
• a May 13, 2026, hearing of the Senate Committee on Armed Services, in which some Members sought details on proposed funding increases and warhead development activities in the Weapons Activities budget, NNSA's plutonium pit production strategy, NNSA's potential contributions to U.S. efforts to denuclearize Iran, U.S. policy on testing nuclear weapons, DNN R&D capabilities, and NNSA workforce issues.³¹

As the FY2027 budget cycle proceeds, this section and Table 4 will be updated to provide details on selected congressional activity related to an FY2027 NDAA, an FY2027 Energy and Water Development Appropriations Act, and other relevant legislation.

FY2027 NNSA Budget Request: Summary of Congressional Action

Footnotes