Imagine you have a ship, running on nuclear reactor. We will assume this ship uses some kind of advanced technology that allows nuclear reactors to function in gravity-less environment.

This ship is in critical shape, having fought 3 alien ships at the same time. The nuclear reactor is going critical, so the captain wants to eject it and have it crash against an alien ship. Crashing the ship itself is against his good judgement, as he wishes to give his crew a chance to survive.

We shall assume that in such a split second decision, it is impossible to calculate detonation timer and it is too late to fit a proximity or remote detonator onto the nuclear reactor.

Now my question,

1) If the critical nuclear reactor crash against an alien ship, will it achieve the same devastating effect as a nuclear weapon as seen in Battlestar Galactica for example?

2) If this happens in the orbit of Earth, will it have any effect on those on the surface, or will it simply be turn into harmless microwave?

closed as off-topic by Mike Scott, Zibbobz, Null, TGnat, Valorum Feb 2 '15 at 21:26

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  • Hi and welcome to Scifi.SE! Sorry, but this question is not on-topic in Sci-Fi. You are asking about the effects of a scientific phenomena, and this site is for asking questions about fictional phenomena and other things related to Fantasy and Science fiction. This question may be better suited on another SE Site stackexchange.com/sites#science . – Zibbobz Feb 2 '15 at 21:10
  • "Advanced technology that allows nuclear reactors to function in a gravity-less environment" ? Absolutely no part of that sentence made any sense whatsoever, and even allowing for proper terminology it's still a nonsensical question. – Shadur Feb 3 '15 at 9:04

Nuclear reactors on Earth tend to fail by going into meltdown. What this means is that the cooling system can no longer keep the reaction under control so it melts everything at the middle and just makes a big mess that won't stop producing heat. For reference, the Earth's core gets its heat from the same thing: nuclear fission without a nuclear blast.

In fact, even a nuclear warhead will impact harmlessly against a ship unless it is detonated. The point of a detonator is to cram a mass of fissionable material greater than the critical mass together fast enough that enough of it reacts before it blows itself apart to produce an explosion. This is handled by conventional explosives surrounding the material and blasting them together.

Therefore it's almost completely certain that an ejected reactor would have absolutely no effect. Neither would a disarmed nuclear warhead.

On top of that, in the future we're likely to be using much better reactors that make use of technologies like molten salt (like in a Thorium reactor) or fissionable material impregnated into a ceramic or other material that's built to prevent enough material coming in close proximity so it won't be possible to even melt down, let alone detonate.

There is also the idea of a fusion reactor. If it's anything like the Tokamak design, there is no significant danger even if you lose containment because the plasma won't do more than cause a bit of corrosion on the inner surface of the reactor.

Now if you have a matter/anti-matter reactor, like in Star Trek, and you lose containment of the anti-matter, that'll make a big boom.


Note that the Project Orion idea actually uses nuclear blasts as a form of propulsion. If that was your propulsion mode, then you'd have a ready supply of nuclear bombs to hurl at your enemy, if you could figure out how to launch them.

  • What if the nuclear reactor is already at meltdown which is only contained by its resistant container, and the impact cracks the container allowing its internals to release lots of directed heat against the ship it hit? Will this cause any significant damage? – Shion Feb 2 '15 at 21:26
  • 1
    @Shion - I doubt it. I think the mechanical damage caused by the impact would be more significant. Any impact in space is potentially catastrophic (at least with current spacecraft). If you're looking for plot material, maybe the core material could splatter on the side of the ship, cool quickly and solidify, and now you've contaminated the other vessel with radiation. Of course any long range spacecraft has some form of radiation shielding due to all the existing radiation floating around out there, so... no. – Scott Whitlock Feb 2 '15 at 21:35
  • @Shion - see my edit. – Scott Whitlock Feb 2 '15 at 21:40

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