The United States Congress has presented a report that deals with the issue of the Navy aiming to procure a next-generation attack submarine.

The report reveals that the US Navy estimates that the procurement of the first SSN(X) class will be pushed to financial year 2040, instead of the earlier dateline of FY 2035.

This delay is largely going to be because of the limitations on the US Navy’s total budget.

The US Navy currently operates nuclear-powered ballistic missile submarines (SSBNs), nuclear-powered cruise missile and special operations forces (SOF) submarines (SSGNs), and nuclear-powered attack submarines (SSNs).

SSNs are known for being general-purpose vessels that can carry out a number of tasks during both peacetime and war.

More about the US Navy’s SSN(X) program

As per the report prepared by Congressional Research Service (CSR), which was released on December 12, the X in the name signifies that the exact design of the boat has not yet been determined.

The Congressional Budget Office (CBO) report from 2023 estimated that in constant FY 2023 currency, the SSN(X) would cost approximately $7.7 billion to $8 billion per unit.

The US Navy projects that the average procurement cost per unit would be $6.7 billion to $7.0 billion, which is 14 to 15 percent lower than CBO’s estimates.

Regarding the size of the vessel, the CBO estimates that the SSN(X) design would have a submerged displacement of about 10,100 tons, about 11% more than that of the SSN-21 design.

The report also quotes the US Navy stating 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,” it further adds.

A mix of features in the new submarine

The US Navy wants SSN(X) to have the speed and payload of the fast and heavily armed “Seawolf (SSN-21) class SSN design, the acoustic quietness and sensors of the Virginia-class design, and the operational availability and service life of the Columbia-class design.”

These expectations could lead to the next-generation attack submarine being larger than the original design of Virginia class vessels – which have a submerged displacement of roughly 7,800 tons.

It also wants the vessel to be powered by a nuclear reactor plant using low-enriched uranium (LEU), rather than the highly enriched uranium (HEU) used on other Navy nuclear-powered ships.

The Navy estimates that 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 $25 billion.

The report states that it has taken 75 years for the US Navy to develop and improve the naval reactor using HEU – and the ones running on LEU would not provide any added advantage.

Questions for US Congress members

The US Navy’s FY 2025 budget has requested $586.9 million for research and development funding related to the SSN(X) program.

The report presents some key issues which Congress needs to ponder over before deciding the future of US Navy’s SSN(X) program.

The CRS report urges Congress to question whether the Navy has correctly identified the required capabilities and its impact on cost of the next-generation attack submarine.

It also urges the Congress to question whether this cost would have an adverse impact on the Navy’s other needs. The question of delaying the procurement of the first SSN(X) unit, and its impact on US’ dominance in the seas is also an important one.

The last issue is the SSN(X) using LEU over HEU fuel, and whether it will provide any benefits to the service.