Redesign may make the Ohio replacement the quietest nuke sub ever

A redesign to the reactor and propulsion system on the Ohio Replacement (OR) would make it the quietest nuclear powered submarine ever built. The Navy is looking at a second attempt at an electric drive system in the OR program. This would go along with a new reactor design that would eliminate the mid-life refueling that currently keeps the boat out of service for up to three years, and allow them to run the entire 50 year life cycle on one fueling. This would also allow them to replace the current 14 Ohio boats with 12 replacements, because they won't have to have the down time for refueling.

This would also eliminate the mechanical drive linkages that are on current subs, eliminating a lot of the potential noise of the sub. This could lead to a significant drop in noise levels, even over the current Ohio class subs (which are already one of the quietest boats ever built).

The design would incorporate an electrical grid inside the sub, which would power the systems as well as the drive. If this works, it would free up more power for systems other than the drive. Currently anywhere from 75-80% of the power from the reactor goes to the drive system.

The Navy tried an electric drive in the 60s and 70s, and found them to be underpowered and maintenance nightmares. It'll be interesting to see what happens with this design, and if it goes forward. They are facing some non-engineering issues as well with the program. They've already slipped it a couple of years, and are trying to cut the budget from 7-8B all the way down to 4.9B.

The U.S. Navy is betting the future of its submarine force on a secret and revolutionary nuclear drive system that aspires to be more efficient and quieter than anything under the water today.

The heart of the planned ballistic missile Ohio Replacement (OR) program will be built around a drive that will not need to be refueled for the 50-year life of the boats and cuts out potentially noisy direct mechanical connection to the drive train. In other words, the Navy’s next-gen subs could be almost silent, and keep running for a half-century straight.

The Navy’s ballistic missile fleet, or boomers, rely on stealth to hide from rival boats, ships and sub-hunting aircraft. The quieter the boat, the harder it is to find. (And these boats are big: the current Ohio boomer is more than a football field and half long displacing 19,000 tons.)

Source