This is why refueling a nuclear submarine can take more than three years

Published on Dec 29, 2025 at 3:29 AM (UTC+4)
by Daisy Edwards

Last updated on Dec 11, 2025 at 8:06 PM (UTC+4)
Edited by Emma Matthews

Refueling a nuclear submarine can take more than three years, and the scale of the job is on another level.

Unlike regular ships, these vessels need ultra-controlled, highly specialized overhaul projects to safely replace their nuclear fuel without a complete disaster occurring.

Some projects, like the USS Louisiana, stretched to 40 months from start to finish.

It’s one of the slowest, most expensive, and highest-stakes maintenance operations in the entire military.

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Refueling a nuclear submarine is a dangerous game

Nuclear submarines are very dangerous pieces of tech, and they run on highly enriched uranium, so swapping that out isn’t as simple as opening a hatch and pouring in more fuel.

The sub has to be hauled into a secure dry dock, completely powered down, and surrounded by radiation-shielding infrastructure before any of the hardest work can begin.

From there, engineers have to carefully dismantle major sections of the submarine to reach the reactor deep inside the hull.

The job requires specialists in nuclear engineering, radiation safety, weapons systems, and even naval architecture.

Every bolt, panel, and cable removed is tracked, inspected, and logged because precision is everything – even a small error in a nuclear submarine can compromise the entire sub.

Why the overhaul takes years

Refueling is only one part of the process, and while the submarine is opened up, the Navy makes the most of the opportunity to rebuild almost every major system on board.

All of that includes electronics, propulsion components, sonar arrays, navigation hardware, and all the facilities where the crew live and work.

At the same time, specialist teams handle radioactive materials under some of the strictest safety rules on the planet.

Obviously, that slows everything down, but it’s necessary when workers are literally inches away from a nuclear reactor.

By the time the job wraps up, the submarine is essentially a new machine built around a fresh nuclear core.

So next time you’re stuck waiting at a fuel pump with your car, just remember: some vehicles need three years to top up.

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Daisy Edwards is a Content Writer at supercarblondie.com. Daisy has more than five years’ experience as a qualified journalist, having graduated with a History and Journalism degree from Goldsmiths, University of London and a dissertation in vintage electric vehicles. Daisy specializes in writing about cars, EVs, tech and luxury lifestyle. When she's not writing, she's at a country music concert or working on one of her many unfinished craft projects.