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Comment by etiam | Hacker News Reader

> U.S. submarines and aircraft carriers run on nuclear power, but they have large fusion reactors on board that have to be replaced on a regular cycle.

sigh To the extent this is true I suspect those "large fusion reactors" are tuned not so much for generating electricity and a great deal for annihilating whatever the carrying missile is pointed at.

But never mind fuzzy thinking at Reuters right now. This is amazing news if holds up. Fingers crossed.

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Looks like they issued the correction

> U.S. submarines and aircraft carriers run on nuclear power, but they have large fission reactors on board that have to be replaced on a regular cycle.

Even the need for regular replacement went away long ago. Our current (old) designs get refueled only once, and new ships don't get refueled at all (the core lasts as long as the hull does). They do all need regular maintenance, but that's true for all U.S. warships.

If by "large" they mean "very small" then, yeah.

Unless I'm missing something, I think you're making a similar mistake.

Submarines and carriers run on a fission reactor. And it powers everything - drives turbines for locomotion, electricity...

At the risk of speaking for the parent, I believe their point was that the only fusion "reactors" on a nuclear submarine are the warheads it carries.

Maybe you're just less bothered than I about the writer conflating fission and fusion when the difference between them makes for a good deal of the newsworthiness of the article.

I'm well aware of the fission reactors in large military ships, but if there is any application of nuclear fusion on them then pretty much the only option today is thermonuclear warheads. It would be really nice if that's about to change.

Most warheads have hollow plutonium pits that are filled with tritium (right before implosion) triggering a fusion reaction from the high heat of the plutonium fission reaction. So no, it's not only the H-Bombs, though those are primarily fusion while tritium is only used to "boost" classic implosion fission warheads.

He's making a joke about how fusion has been used successfully for decades, but only for bombs. Thus, aircraft carriers and submarines do have fusion devices on board, but they're only used for destructive purposes.

Must be early. A few people didn't get your joke/sarcasm.

I cringed when I saw that line too.

From what I've heard, the reactor actually outlives the ship, no?

https://en.wikipedia.org/wiki/United_States_naval_reactors#m...

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Civilian power reactors need refueling at about that pace, but Nimitz-class carriers "are capable of operating continuously for over 20 years without refueling"

http://en.wikipedia.org/wiki/Nimitz-class_aircraft_carrier#P...

25 years for current aircraft carriers [1]

[1]http://en.wikipedia.org/wiki/Refueling_and_Overhaul

I believe you're misunderstanding, those ships run on power generated by a nuclear reactor. A reactor is like when you think of a regular nuclear power plant, it's not part of a missile.

I think they understand; they were joking that the only things on the ship which involve fusion are the nuclear warheads.

You're right, but it was a joke pointing out an error in the article. They originally said the carriers run on fusion reactors, but it's been fixed.

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