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Updated July 15, 2022
Navy Next-Generation Attack Submarine (SSN[X]) Program:
Background and Issues for Congress
Introduction
Procurement Schedule
The Navy wants to begin procuring a new class of nuclear-
The Navy wants to shift from procuring Virginia-class
powered attack submarine (SSN), called the Next-
boats to procuring SSN(X)s in the mid-2030s.
Generation Attack Submarine or SSN(X), in the mid-2030s.
The SSN(X) would be the successor to the Virginia-class
Figure 1. Virginia-Class Attack Submarine (SSN)
SSN design, which the Navy has been procuring since
FY1998. The Navy’s proposed FY2023 budget requests
$237.0 million in research and development funding for the
SSN(X) program.
Submarines in the U.S. Navy
The U.S. Navy operates nuclear-powered ballistic missile
submarines (SSBNs), nuclear-powered cruise missile and
special operations forces (SOF) submarines (SSGNs), and
nuclear-powered attack submarines (SSNs). The SSNs are
general-purpose submarines that can perform a variety of
peacetime and wartime missions.
Virginia-Class Program
Source: Cropped version of photograph accompanying Dan Ward,
As mentioned above, the Navy has been procuring
“Opinion: How Budget Pressure Prompted the Success of Virginia-
Virginia-class SSNs (Figure 1) since FY1998. Since
Class Submarine Program,” USNI News, November 3, 2014. The
FY2011, the Navy has been procuring them at a rate of two
caption states that it shows USS Minnesota (SSN-783) under
boats per year. When procured at a rate of two boats per
construction in 2012, and credits the photograph to the U.S. Navy.
year, VPM-equipped Virginia-class SSNs have a current
estimated procurement cost of about $3.6 billion per boat.
Design of the SSN(X)
For additional information on Navy submarine programs,
The Navy states that the SSN(X)
see CRS Report RL32418, Navy Virginia (SSN-774) Class
will be designed to counter the growing threat posed
Attack Submarine Procurement: Background and Issues for
by near peer adversary competition for undersea
Congress, by Ronald O'Rourke, and CRS Report R41129,
supremacy. It will provide greater speed, increased
Navy Columbia (SSBN-826) Class Ballistic Missile
horizontal payload capacity, improved acoustic
Submarine Program: Background and Issues for Congress,
superiority, and higher operational availability.
by Ronald O'Rourke.
SSN(X) will conduct full spectrum undersea
Submarine Construction Industrial Base
warfare and be able to coordinate with a larger
U.S. Navy submarines are built by General Dynamics’
contingent of off-hull vehicles, sensors, and
Electric Boat Division (GD/EB) of Groton, CT, and
friendly forces. It will retain and improve multi-
Quonset Point, RI, and Huntington Ingalls Industries’
mission... capability and sustained combat presence
Newport News Shipbuilding (HII/NNS), of Newport News,
in denied waters.
VA. These are the only two shipyards in the country
(Budget-justification book for FY2023 Research,
capable of building nuclear-powered ships. GD/EB builds
Development, Test, and Evaluation, Navy account,
submarines only, while HII/NNS also builds nuclear-
Vol. 3 [Budget Activity 5], p. 1305.)
powered aircraft carriers. The submarine construction
industrial base also includes hundreds of supplier firms, as
Navy officials have stated that the Navy wants the SSN(X)
well as laboratories and research facilities, in numerous
to be an “apex predator.” More specifically, they have
states. Much of the material procured from supplier firms
stated that the Navy wants the SSN(X) to incorporate the
for building submarines comes from sole-source suppliers.
speed and payload the Navy’s fast and heavily armed
Seawolf (SSN-21) class SSN design, the acoustic quietness
SSN(X) Program
and sensors of the Virginia-class design, and the operational
availability and service life of the Columbia-class design.
Program Designation
In the designation SSN(X), the “X” means that the exact
These requirements will likely result in an SSN(X) design
design of the boat has not yet been determined.
that is larger than the original Virginia-class design, which
has a submerged displacement of about 7,800 tons, and
https://crsreports.congress.gov
Navy Next-Generation Attack Submarine (SSN[X]) Program: Background and Issues for Congress
possibly larger than the original SSN-21 design, which has
for using LEU for the SSN(X) that was provided by the
a submerged displacement of 9,138 tons. Due to
Navy to CRS in unclassified form stated:
technological changes over the years for improved quieting
It is not practical to substitute LEU into existing
and other purposes, the designs of U.S. Navy submarines
with similar payloads have generally been growing in
naval fuel systems or to design a VIRGINIA Class
displacement from one generation to the next.
Submarine (VCS) replacement [i.e., the SSN(X)]
around an unproven advanced LEU fuel concept.
Potential Procurement Cost
Developing a newly designed submarine capable of
An April 2021 Congressional Budget Office (CBO) report
later acceptance of an LEU reactor core would also
states that in constant FY2021 dollars, the SSN(X)’s
involve insertion of substantial margin (e.g.,
average unit procurement cost is estimated at $5.8 billion
increased hull size) that would be difficult to
by the Navy and $6.2 billion by CBO—figures that are
estimate accurately at present and costly to
substantially higher than the $3.6 billion unit procurement
implement. If future United States policy requires a
cost of a VPM-equipped Virginia-class SSN. The report
shift to LEU, at least 15 years of advanced fuel
states that CBO’s estimate assumes that the SSN(X) design
development and significant investment would be
would be similar in size and capabilities to the SSN-21
required. This development timeline makes it
design.
impractical to design a lead ship VCS replacement
with an LEU reactor while meeting the Navy’s
Issues for Congress
schedule.
Issues for Congress include the following:
FY2023 Funding Request and
whether the Navy has accurately identified the
SSN(X)’
Congressional Action
s required capabilities and accurately analyzed
the impact that various required capabilities can have on
The Navy’s proposed FY2023 budget requests $237.0
the SSN(X)’s cost;
million in research and development funding for the
SSN(X) program, including $143.9 million in Project 2368
the potential impact of the SSN(X) program on funding
(SSN[X] Class Submarine Development) within Program
that will be available for other Navy program priorities;
Element (PE) 0604850N (SSN[X]), which is line 154 in the
Navy’s FY202
whether it would be technically feasible for the SSN(X)
3 research and development account, and
to be powered by a reactor plant using low-enriched
$93.1 million in Project 2370 (Next Generation Fast Attack
uranium (LEU), rather than the highly enriched uranium
Nuclear Propulsion Development) within PE 0603570N
(HEU) used on other Navy nuclear-powered ships, and
(Advanced Nuclear Power Systems), which is line 48.
if so, what impact that would have on nuclear arms
control and nonproliferation efforts and SSN(X) costs
The House Armed Services Committee, in its report
and capabilities; and
(H.Rept. 117-397 of July 1, 2022, pages 473 and 478) on
the FY2023 National Defense Authorization Act (H.R.
whether each SSN(X) should be built jointly by GD/EB
7900), and the House Appropriations Committee, in its
and HII/NNS (the approach used for building Virginia-
report (H.Rept. 117-388 of June 24, 2022, pages 198 and
class SSNs and, in modified form, for building
202) on the FY2023 DOD Appropriations Act (H.R. 8236),
Columbia-class SSBNs), or whether individual SSN(X)s
both recommend approving the Navy’s FY2023 research
should instead be completely built within a given
and development funding requests for the SSN(X) program.
shipyard (the separate-yard approach used for building
earlier Navy SSNs and SSBNs).
Ronald O'Rourke, Specialist in Naval Affairs
Regarding the third issue above, a January 2020
IF11826
Department of Energy (DOE) National Nuclear Security
Administration (NNSA) report to Congress on the potential
https://crsreports.congress.gov
Navy Next-Generation Attack Submarine (SSN[X]) Program: Background and Issues for Congress
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
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