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Weapons of Mass Destruction (WMD)

Department of Defense Office of Inspector General

(U) Evaluation of Nuclear Ballistic Missile Submarine (SSBN) Sustainment



Our objective was to determine whether the Navy can sustain the current Ohio-class Nuclear Ballistic Missile Submarines (SSBNs) until the replacement Columbia-class SSBNs are fielded.


The United States maintains a nuclear triad consisting of manned bombers, land-based intercontinental ballistic missiles, and ballistic missile submarines capable of delivering nuclear weapons. Our review focused on Ohio-class SSBN sustainment.

The Navy decided in 1998 to extend the original 30-year service life of the Ohio-class to 42 years. The first Ohio-class SSBN is scheduled to be retired in 2027; the remaining 13 are scheduled to be retired one per year until 2040.

According to the Navy submarine program office, the first Columbia-class SSBN is expected to enter service in 2031. An additional 11 Columbia-class SSBNs are scheduled to be delivered approximately one per year until the last two join the fleet by 2042.

Each Ohio-class SSBN undergoes three types of maintenance cycles during its service life:

  • Incremental Refit This 35-day maintenance period consists of scheduled repairs, maintenance, and inspections, as well as unscheduled repairs and minor modernization tasks such as sonar, torpedo fire control, and navigation systems.
  • Extended Refit Period. This 7- to 8-month maintenance period replaces and refurbishes the major components of the hull and internal systems.
  • Engineered Refueling Overhaul (ERO). This 27-month overhaul occurs around the 20 –year point for the Ohio-class SSBN and includes extensive inspections, structural repairs, and a nuclear reactor refueling to extend the submarines service life.


The Navy has taken action to sustain the Ohio-class SSBNs at the minimum USSTRATCOM requirements until the replacement Columbia-class SSBNs are fielded.

In order to maintain USSTRATCOM requirements, the Secretary of the Navy designated sustainment of the Ohio-class SSBNs as the Navy's highest priority. Accordingly, the Navy has taken several steps to improve sustainment, which include the following.

  • The Navy has placed SSBNs ahead of aircraft carriers in maintenance priority.

o   This shift has reduced the time required for SSBN EROs. For example, the USS Maine completed the first of two ERO phases with a 43-percent reduction in cycle-time in comparison to the last SSBN that completed an ERO.

  • Shipyards have direct hiring authority to address maintenance manpower shortages.

o   The workforce size at shipyards now matches the workload. For example, in the past 4 years, Puget Sound Naval Shipyard alone hired more than 6,700 employees.

  • The Navy has developed programs to accelerate and improve training of shipyards’ new hires.

o   Shipyards use apprenticeships to develop an experienced workforce. In a recent pilot program, the Navy reduced the journeyman training time to repair a particular valve from 24 months to 10 weeks using a task based learning method.

  • The Navy has improved SSBN maintenance procedures and schedules.

o   Replicas allow personnel to practice difficult tasks prior to performing the task aboard an SSBN.

o   Personnel deploy as needed to conduct inspections and prepare for Incremental Refit maintenance while the submarine is returning to port.

o   Personnel reduced overdue Preventive Maintenance Requirements due to unavailable parts from 37 to 12 instances over a one-year period.



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