Key Points – The US Navy’s SSN(X) program envisions its most technologically advanced attack submarine, designed to combine the Seawolf’s speed and payload, the Virginia’s stealth and sensors, and the Columbia’s longevity to counter peer adversaries.
-However, this ambition comes with a steep price, estimated at $5.8 to $6.2 billion per submarine—more than double the Virginia-class.
-The Navy has rejected lower-cost Low-Enriched Uranium fuel, citing performance degradation.
-These ballooning costs threaten to reduce the number of SSN(X)s procured, strain already challenged shipyard capacity, and could potentially delay submarine deliveries to Australia under the AUKUS agreement.
SSN(X) Might the Be Navy’s Great Submarine Failure
The United States Navy’s upcoming SSN(X) submarine, once in the water, will be the most technologically advanced submarine fleet the United States Navy has ever had in service. By combining the best aspects of several previous submarine classes, the new submarines will offer a potent blend of speed, stealth, and a prodigious offensive capability.
The US Navy explains that the SSN(X) “will be designed to counter the growing threat posed by near-peer adversary competition for undersea supremacy. It will provide greater speed, increased horizontal [i.e., torpedo-room] payload capacity, improved acoustic superiority and non-acoustic signatures, and higher operational availability. SSN(X) will conduct full spectrum undersea warfare and be able to coordinate with a larger contingent of off-hull vehicles, sensors, and friendly forces.”
Furthermore, the US Navy has explained it would like the upcoming SSN(X) submarine to combine the very high sprint speed and payload capacity of the Cold War-era Seawolf-class, a particularly heavily armed submarine, with the advanced sensor suite and low acoustic signature of the Virginia-class submarines and the long service life and high operational ability of the Columbia-class subs.
However, one of the obstacles facing the program is cost—which is rapidly ballooning.
Show me the Money on SSN(X)
One of the suggested issues for Congress—but not explored—is using low-enriched uranium as fuel rather than the highly enriched uranium typically used as part of a cost-saving effort. However, the US Navy has pushed back against exploring this option.
In a paper given to the Congressional Research Service, the Navy explained, “Prior estimates have been 10-15 years and $1B to complete enough work to determine whether a fuel system may be viable and what performance may be achieved. Success is not assured. An optimistic estimate of total time to develop and deploy a naval LEU fuel system is 20- 30 years (which includes the 10-15 years initial development program) and $25B. This does not include the cost of additional force structure to cover the mission of submarines being refueled.”
Furthermore, “The US Navy has developed and improved technology using highly enriched uranium (HEU) fuel over the past 75 years, providing the US Navy with unmatched asymmetric advantages in naval warfare. US Navy warships requirements determine naval fuel system design features, including the use of HEU fuel. An LEU fuel system would not provide any military benefit to the performance of US naval reactors. It would decrease the available energy in the propulsion plant, negatively affect reactor endurance, reactor size, ship costs, force structure, and maintenance infrastructure.”
The US Navy has not yet made clear how many SSN(X) submarines it would ultimately like to procure.
Still, in previous years, it has said it would like to have a fleet of around 66 fast-attack submarines, including the SSN(X) class and the US Navy’s current Virginia-class submarines. The crux of the procurement issue is cost.
Compared to the Virginia-class, the SSN(X) submarines will cost significantly more—though how much exactly remains to be seen. While the Virginia-class submarines cost approximately $2.8 billion per hull, the US Navy has estimated the SSN(X) will cost $5.8 billion each — while the Congressional Budget Office estimated their cost at a whopping $6.2 billion per submarine.
Implications
If the SSN(X) ‘s per-hull costs continue to increase, the US Navy might be forced to procure fewer submarines than it needs, potentially undermining the future submarine force structure. Additionally, the SSN(X) will compete for funding with the Columbia-class SSBNs, the modernization of the surface fleet, investment in unmanned naval systems, and other high-priority (and costly) naval programs.
The two shipbuilding defense industry heavyweights of Electric Boat and Newport News Shipbuilding are struggling to meet their current production schedules for the Virginia-class and Columbia-class submarines. With the addition of another submarine class, those firms could risk falling woefully behind production schedules, leading to future delays and production bottlenecks. If the class’ production falls off, blowback from lawmakers could result in a significant scaling back of the program.
What Happens Now on SSN(X)?
One tangible consequence of higher than projected SSN(X) costs could be a delay in the submarine delivery to Australia as part of the tripartite AUKUS agreement. As part of that agreement between the United States, the United Kingdom, and Australia, nuclear propulsion technology was promised to Canberra.
However, suppose the United States cannot meet its own submarine needs. In that case, the future Australian nuclear submarine fleet may be delayed or curtailed — which is not only bad news for the Royal Australian Navy and American shipbuilders.
U.S. Navy Submarines Photo Essay
(July 9, 2018) – Multi-national Special Operations Forces (SOF) participate in a submarine insertion exercise with the fast-attack submarine USS Hawaii (SSN 776) and combat rubber raiding craft off the coast of Oahu, Hawaii during Rim of the Pacific (RIMPAC) exercise, July 9. Twenty-five nations, 46 ships and five submarines, about 200 aircraft, and 25,000 personnel are participating in RIMPAC from June 27 to Aug. 2 in and around the Hawaiian Islands and Southern California. The world’s largest international maritime exercise, RIMPAC provides a unique training opportunity while fostering and sustaining cooperative relationships among participants critical to ensuring the safety of sea lanes and security of the world’s oceans. RIMPAC 2018 is the 26th exercise in the series that began in 1971.` (U.S. Navy photo by Mass Communication Specialist 1st Class Daniel Hinton)
U.S. Navy Virginia-Class Submarine.
Western Australia, Australia (Feb. 25, 2025) The Virginia-class fast-attack submarine USS Minnesota (SSN 783) prepares to moor at HMAS Stirling, Western Australia, Australia, Feb. 25, 2025. Minnesota arrived in Western Australia kicking off the first of two planned U.S. fast-attack submarine visits to HMAS Stirling in 2025. Minnesota is currently on deployment supporting the U.S. 7th Fleet, the U.S. Navy’s largest forward-deployed numbered fleet, operating with allies and partners in preserving a free and open Indo-Pacific region. (U.S. Navy photo by Lt. James Caliva)
Virginia-Class Submarine.
Image of Virginia-Class Submarine. Image Credit: Creative Commons.
Virginia-Class. Image Credit: Creative Commons.
About the Author: Caleb Larson
Caleb Larson is an American multiformat journalist based in Berlin, Germany. His work covers the intersection of conflict and society, focusing on American foreign policy and European security. He has reported from Germany, Russia, and the United States. Most recently, he covered the war in Ukraine, reporting extensively on the war’s shifting battle lines from Donbas and writing on the war’s civilian and humanitarian toll. Previously, he worked as a Defense Reporter for POLITICO Europe. You can follow his latest work on X.
