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Updated April 25, 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 incorporate the speed and payload the Navy’s fast and
states. Much of the material procured from supplier firms
heavily armed Seawolf (SSN-21) class SSN design, the
for building submarines comes from sole-source suppliers.
acoustic quietness and sensors of the Virginia-class design,
and the operational availability and service life of the
SSN(X) Program
Columbia-class design.
Program Designation
Potential Procurement Cost
In the designation SSN(X), the “X” means that the exact
An April 2021 Congressional Budget Office (CBO) report
design of the boat has not yet been determined.
states that in constant FY2021 dollars, the SSN(X)’s
average unit procurement cost is estimated at $5.8 billion
https://crsreports.congress.gov
Navy Next-Generation Attack Submarine (SSN[X]) Program: Background and Issues for Congress
by the Navy and $6.2 billion by CBO—figures that are
It is not practical to substitute LEU into existing
substantially higher than the $3.6 billion unit procurement
naval fuel systems or to design a VIRGINIA Class
cost of a VPM-equipped Virginia-class SSN.
Submarine (VCS) replacement [i.e., the SSN(X)]
Issues for Congress
around an unproven advanced LEU fuel concept.
Developing a newly designed submarine capable of
Issues for Congress include the following:
later acceptance of an LEU reactor core would also
whether the Navy has accurately identified the
involve insertion of substantial margin (e.g.,
SSN(X)’s required capabilities and accurately analyzed
increased hull size) that would be difficult to
the impact that various required capabilities can have on
estimate accurately at present and costly to
the SSN(X)’s cost;
implement. If future United States policy requires a
shift to LEU, at least 15 years of advanced fuel
the potential impact of the SSN(X) program on funding
development and significant investment would be
that will be available for other Navy program priorities;
required. This development timeline makes it
whether it would be technically feasible for the SSN(X)
impractical to design a lead ship VCS replacement
to be powered by a reactor plant using low-enriched
with an LEU reactor while meeting the Navy’s
uranium (LEU), rather than the highly enriched uranium
schedule.
(HEU) used on other Navy nuclear-powered ships, and
if so, what impact that would have on nuclear arms
FY2023 Funding Request and
control and nonproliferation efforts and SSN(X) costs
Congressional Action
and capabilities; and
The Navy’s proposed FY2023 budget requests $237.0
million in research and development funding for the
whether each SSN(X) should be built jointly by GD/EB
SSN(X) program, including $143.9 million in Project 2368
and HII/NNS (the approach used for building Virginia-
(SSN[X] Class Submarine Development) within Program
class SSNs and, in modified form, for building
Element (PE) 0604850N (SSN[X]), which is line 154 in the
Columbia-class SSBNs), or whether individual SSN(X)s
Navy’s FY2023 research and development account, and
should instead be completely built within a given
$93.1 million in Project 2370 (Next Generation Fast Attack
shipyard (the separate-yard approach used for building
Nuclear Propulsion Development) within PE 0603570N
earlier Navy SSNs and SSBNs).
(Advanced Nuclear Power Systems), which is line 48.
Regarding the third issue above, a January 2020
Department of Energy (DOE) National Nuclear Security
Administration (NNSA) report to Congress on the potential
for using LEU for the SSN(X) that was provided by the
Ronald O'Rourke, Specialist in Naval Affairs
Navy to CRS in unclassified form stated:
IF11826
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
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
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https://crsreports.congress.gov | IF11826 · VERSION 14 · UPDATED