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.)

Now the Navy is developing an innovation that attempts to give OR boomers the quietest nuclear engine yet by “going to [an] electric drive,” Sean Stackley, the Navy’s chief weapons buyer, said in a January interview with the U.S. Naval Institute.