Could one make a Enriched Uranium...sword? [Archive]

Ranchoth

02-05-2004, 02:00 AM

There's no easy way to put this, so I'll just say it...could I make a sword out of enriched Uranium? (http://en.wikipedia.org/wiki/Enriched_uranium)

Say, we're making a typical "bastard sword," (http://members.aol.com/dargolyt/TheForge/bastard.htm) just with HEU in lieu of Steel for the blade.

Would it be too radioactive to handle safely? If not, would it feel warm to the touch?

How much heavier than a Steel sword would it be? Could an average person even lift it, much less wield it?

Even if it was non-radioactive and light weight enough—which I doubt—to wield, could the metal even stand up to the punishment of combat? Would it be too brittle, or inflexible?

Finally...could you build a working reactor that would use several of these swords as fuel rods? (I'm thinking that fuel rod insertion would be manual...kind of like a reverse "Sword in the Stone" deal.)

So...any thoughts? Aside from that I shouldn't come up with "smart" ideas after watching anime steampunk? ;)

Well, thanks for your patience,

Ranchoth

Mangetout

02-05-2004, 03:01 AM

Heavier metals tend to be quite malleable; I can't find any plain English information on the structural properties though.

Desmostylus

02-05-2004, 05:59 AM

How much heavier than a Steel sword would it be? Could an average person even lift it, much less wield it? Uranium is about 2.4 times as dense as iron. So if your steel sword weighed say 10 kg, the uranium sword would weigh 24 kg.Would it be too radioactive to handle safely?Yes, but the answer really depends on exactly how radioactive it was, which depends on how enriched the uranium was, how much of it there was, what shape it was, and what other materials were close to it or built into it. And "safely" is not an objective measure anyway. I certainly wouldn't want one anywhere near me, but the hero in a novel may well take the risk if he's only going to be holding it for say a few minutes....would it feel warm to the touchYou could make one so that it was warm to the touch. It wouldn't be a good idea to be anywhere near it, because it would mean that you had a critical mass, i.e. a self-sustaining chain reaction. That's a very dodgy proposition, because you could accidentally bring your sword close to a moderator material, e.g. charcoal, which could make your sword supercritical: meltdown or "boom".Finally...could you build a working reactor that would use several of these swords as fuel rods? (I'm thinking that fuel rod insertion would be manual...kind of like a reverse "Sword in the Stone" deal.)Definitely.

kanicbird

02-05-2004, 06:06 AM

Think of the weight of a lead sword. You would have trouble lifting it. Also using depleated Uranium would be a healthier choice.

Achernar

02-05-2004, 06:32 AM

Yes, but the answer really depends on exactly how radioactive it was, which depends on how enriched the uranium was, how much of it there was, what shape it was, and what other materials were close to it or built into it. And "safely" is not an objective measure anyway. I certainly wouldn't want one anywhere near me, but the hero in a novel may well take the risk if he's only going to be holding it for say a few minutes.24kg of U-235 has 6.1e25 atoms for an activity level of 1.9e9 Bq = 52 mCi. U-235 produces 4.7MeV alpha particles, so if you absorbed 10% of this radiation, that's 0.0014 J/s. If you massed 80kg, that's 1.8 millirads/sec, or 35 millirems/sec. One hour would give you 126 rems of exposure, which will have biological effects. A few hours would be fatal.

However, I'm thinking that there should be some sort of reduction factor since it's only alphas. Did I leave out a step?

Mangetout

02-05-2004, 06:41 AM

You could make one so that it was warm to the touch. It wouldn't be a good idea to be anywhere near it, because it would mean that you had a critical mass, i.e. a self-sustaining chain reaction. That's a very dodgy proposition, because you could accidentally bring your sword close to a moderator material, e.g. charcoal, which could make your sword supercritical: meltdown or "boom".Definitely.
I thought a moderator had the opposite effect of, well, moderating (i.e. restricting or slowing down) nuclear reactions.

Desmostylus

02-05-2004, 06:56 AM

No. Neutrons from fission are fast moving. Those fast neutrons are less likely to be absorbed by another uranium nucleus than neutrons that have been absorbed and re-emitted by a moderator (in the sense of go-between or interface) and slowed down in the process.

swansont

02-05-2004, 07:10 AM

24kg of U-235 has 6.1e25 atoms for an activity level of 1.9e9 Bq = 52 mCi. U-235 produces 4.7MeV alpha particles, so if you absorbed 10% of this radiation, that's 0.0014 J/s. If you massed 80kg, that's 1.8 millirads/sec, or 35 millirems/sec. One hour would give you 126 rems of exposure, which will have biological effects. A few hours would be fatal.

However, I'm thinking that there should be some sort of reduction factor since it's only alphas. Did I leave out a step?

Alphas tend not to penetrate, so they shouldn't be a risk for external exposure. You'd be depositing the energy in you outer layer of dead skin, or clothing. If you're a sword swallower, though, it would be trouble.

swansont

02-05-2004, 07:15 AM

It wouldn't be a good idea to be anywhere near it, because it would mean that you had a critical mass, i.e. a self-sustaining chain reaction. That's a very dodgy proposition, because you could accidentally bring your sword close to a moderator material, e.g. charcoal, which could make your sword supercritical: meltdown or "boom".

I think a single sword is so far from a good geometry that there isn't much risk of criticality, though if you were wielding it, you are already close to a moderating material - the human body, and all of its water.

As for "boom," frankly, no. Making a bomb just isn't as easy as all that.

Desmostylus

02-05-2004, 07:23 AM

However, I'm thinking that there should be some sort of reduction factor since it's only alphas. Did I leave out a step?Where did you get the alphas from? The U235 goes to two daughters (or more) and some neutrons. It's conceivable that a daughter could be an alpha. There's no reason to assume that there are no neutrons emitted and that one daughter must always be an alpha.

Desmostylus

02-05-2004, 07:45 AM

As for "boom," frankly, no. Making a bomb just isn't as easy as all that.That's a fairly silly statement. Making something that will explode, if you already have the U235, is very easy.

In an uncontained reaction, like with the sword we're discussing, everything depends on the mass of uranium involved, the shape and the moderators. At the minimum, your sword turns to molten slag, because the energy being generated by the chain reaction is sufficient to do so. At a slightly higher rate of energy release, the sword gets blown to pieces. At still higher rates, we get Hiroshima.

You could argue that a sword wouldn't make a good bomb, because it required too much uranium for a given explosive yield, or because it was too dangerous, or whatever. You couldn't argue that it wouldn't make a bomb at all.

Achernar

02-05-2004, 07:50 AM

Where did you get the alphas from? The U235 goes to two daughters (or more) and some neutrons. It's conceivable that a daughter could be an alpha. There's no reason to assume that there are no neutrons emitted and that one daughter must always be an alpha.
I think maybe we're thinking about different things. I was talking about the radioactive decay of U-235, not fission.

I realize that 24 kg is well over critical mass for U-235, but I was just using that as example; in practice it would have to be much, much lighter. 10kg is a huge overestimate for the mass of a steel bastard sword.

swansont

02-05-2004, 08:11 AM

That's a fairly silly statement. Making something that will explode, if you already have the U235, is very easy.

In an uncontained reaction, like with the sword we're discussing, everything depends on the mass of uranium involved, the shape and the moderators. At the minimum, your sword turns to molten slag, because the energy being generated by the chain reaction is sufficient to do so. At a slightly higher rate of energy release, the sword gets blown to pieces. At still higher rates, we get Hiroshima.

You could argue that a sword wouldn't make a good bomb, because it required too much uranium for a given explosive yield, or because it was too dangerous, or whatever. You couldn't argue that it wouldn't make a bomb at all.

I think you can argue that it wouldn't make a bomb at all. Geometry is very important. Nuclear reactors, with a much more efficient geometry, aren't candidates for nuclear explosions because of this. Even if you had prompt supercriticality, once the material starts to melt, the geometry changes, and all bets are off. Bombs depend on the reactions happening very quickly. Neutron leakage needs to be minimized. You don't get that with a sword.

Now, if you want to re-cast the sword in a different geometry, then you can start talking bomb, but that's a different argument.

smiling bandit

02-05-2004, 08:17 AM

Uranium is about 2.4 times as dense as iron.

You could certainly lift it. A good sword can eigh as little as two pounds. Strange but true: they're not really that heavy. You could even lift a big German Zweihaender.

AndrewL

02-05-2004, 09:11 AM

MikeS

02-05-2004, 09:39 AM

Pop1

02-05-2004, 09:45 AM

Uranium shavings are pyrophoric, meaning that they have an annoying tendency to burst into flame when exposed to air. This site (http://web.ead.anl.gov/uranium/guide/ucompound/propertiesu/alloys.cfm) seems to imply that the same thing will happen if the surface is allowed to oxidize (which it apparently does quite readily.)

On the other hand, a sword that spontaneously bursts into flame might be kind of cool, too.

I don't know about that. We had some pieces of depleted Uranium sitting in stock where I used to sell specialty chemicals. We never had any problems with them bursting into flame.

Depleted Uranium is used as shielding for tanks and such, and so I doubt it would be brittle. Things that break apart easily make poor armor.

I can't say what kind of edge it would hold, though.

Wesley Clark

02-05-2004, 10:32 AM

Depleted uranium would be a better method. its obviously easier to come across than enriched uranium, and its also 2.5x as dense as steel. Plus depleted uranium is already used in weapons.

Umbriel

02-05-2004, 10:32 AM

Here's a sample Bastard Sword (http://www.armor.com/2000/catalog/item195.html), with weight given as 3.1lbs (1.4kg). A Uranium sword would therefore weigh approximately 7.4lbs (3.4kg). Probably very awkward for a real swordsman, but nothing you couldn't get accustomed to with training. It wouldn't make for very deft parrying, though. Mighty barbarian warriors or evil Witch Kings (loved that morning star in ROTK, BTW), of course, wouldn't be unduly inconvenienced.

This source (http://pearl1.lanl.gov/periodic/elements/92.html) asserts that U238 is normally slightly softer than steel, which is at odds with this site (http://pearl1.lanl.gov/periodic/elements/92.html), which asserts that it is the second hardest common metal known, after Tungsten. Even given that the depleted uranium used in projectiles is subjected to a classified hardening process, it seems to be an open question just how hard the enriched uranium sword would be.

Of course, a sword slightly softer than steel would still be a pretty effective weapon. The Romans and Greeks did fine with iron and bronze, after all. Moreover, the increased mass of the uranium sword would make it cleave that much more effectively. If, as a natural characteristic or due to alloying or hardening, the uranium sword is also harder than steel, it'd likely perforate armor wonderfully.

The pyrophoric quality of depleted uranium only kicks in at about 500C. It enhances the effect of high velocity projectiles, which easily reach that temperature on impact, but would not make much difference to a sword. Granulated uranium's pyrophoric qualities are accentuated, presumably because of increased oxygen exposure, and even friction. A sword would likely develop a "patina" that would limit further reactivity. However...

Another quality that makes depleted uranium desirable in projectiles is "adiabatic shear banding" (http://www.mindfully.org/Nucs/2003/DU-Amorphous-Tungsten-Alloy30jul03.htm). I.e., it's self-sharpening. A uranium sword might therefore hold a wicked edge. Moreover, the pyrophoric qualities of particles lost on impact with an enemy's sword or armor would make for a nicely showy spray of sparks, beyond what a sword fight would normally produce.

I've heard that even depleted uranium is slightly warm to the touch, so I expect that an enriched uranium sword would be as well, even if no fission activity was going on. All in all, I'd say go for it! Just be sure to wear a lead codpiece.

BlackPheonix

02-05-2004, 10:33 AM

What about the mechanical properties? Does uranium hold an edge well? Is it malleable, brittile, or tough? If you whack something with your uranium sword, will it hold up like a steel sword would, or will it bend or shatter? This will help determine the minimum weight for the sword - part of the reason good swords can be made suprisingly lightweight is because they're made from very good, high strength-to-weight steel alloys.

Lets stick to depleted uranium. It already has the properties we need.

Ok, just read a lot about it and here's what I've found:

Using uranium would be incredibly stupid, depleted would be excellent. Aside from being absurdly heavy your sword would be considerably stronger and tougher than steel. You'd probably want some sort of alloy just for weight concerns. Any wounds inflicted on your foe might be toxic and definitely radioactive but I'm not sure what affects would be with so little exposure.

On a side note, if you were wearing DU armor you would be virtually unstoppable... presuming you could move. Any kind of DU cross-bolt or arrow (not sure how well the latter would work) would be a formidable armor-piercing weapon.

Achernar

02-05-2004, 10:50 AM

I've heard that even depleted uranium is slightly warm to the touch, so I expect that an enriched uranium sword would be as well, even if no fission activity was going on.That's because U-238 is also radioactive, though only about one-seventh as much as U-235.

AndrewL

02-05-2004, 10:52 AM

According to Matweb (http://www.matweb.com), Uranium (http://www.matweb.com/search/SpecificMaterial.asp?bassnum=MEU000) compares poorly with a decent steel alloy (http://www.matweb.com/search/SpecificMaterial.asp?bassnum=M4140A). It's slightly less hard, has significantly worse tensile strength, and has almost no ability to elongate without breaking. This, along with the much greater density, makes for a poor choice for a sword; it'll be much more likely break if you actually use it to hit something.

The Matweb site doesn't state if the properties given are for natural, depleted or enriched uranium, but it probably doesn't matter. Having the same electron valences and nearly the same weight, U235 and U238 should have nearly identical chemical and mechanical properties.

Flash-57

02-05-2004, 10:58 AM

I certainly wouldn't want one anywhere near me, but the hero in a novel may well take the risk if he's only going to be holding it for say a few minutes.

But, if the hero had already mutated from contact with radioactivity, there'd be no additional problem.

Cervaise

02-05-2004, 12:19 PM

When people ask me why I love the SDMB, this is exactly the sort of thing I mean. The strangest, silliest questions provoke the most interesting and thoughtful discussions. Where else would an inquiry about a sword made out of — heh — uranium — heh heh — provoke such a technically detailed roundtable?

Sorry to gush. Please continue. :)

koeeoaddi

02-05-2004, 01:51 PM

When people ask me why I love the SDMB, this is exactly the sort of thing I mean.
Amen. I couldn't get this thread open fast enough. I've been wondering about the possibility ever since I read an adventure/fiction/potboiler novel, where the solution was a bit like Colonel Mustard in the Library with a hot sword. I can't think of a way of naming the book without spoiling it, but wondered if the OP had a novel in mind when he asked the question.

Chronos

02-05-2004, 01:57 PM

Lets stick to depleted uranium. It already has the properties we need.Depleted uranium most assuredly does not have the properties we need. The OP wants the sword to be radioactive. He wants to be able to start up a nuclear reactor by sliding the sword into a slot. If we didn't want a radioactive sword, we'd just use steel and be done with it.

The real question is how effective we want this thing to be as a sword. Is the protagonist going to be regularly engaging in heavy swordfights, or is he just going to draw it and everyone cowers in fear? The latter isn't too implausible... It would be very easy for a radioactive weapon to develop a reputation for being cursed. Additionally, in the event that it breaks in combat, would the mystique of the scenario allow for the blade to be re-forged? It'd still be uranium, so all of the "interesting" properties would be maintained.

Kinthalis

02-05-2004, 02:32 PM

Here's a sample Bastard Sword (http://www.armor.com/2000/catalog/item195.html), with weight given as 3.1lbs (1.4kg).

Nit pick - that's a longsword. ;)

N9IWP

02-05-2004, 03:23 PM

Depleted uranium used in a rotor:
http://www.cartercopters.com/High%20Technology%20Gyroplane.htm

(scroll about half way down, or search on uranium)

I've lifted said rotor (one blade), it is doable, but required effort.

Brian

Umbriel

02-05-2004, 03:33 PM

Well, they called it a Bastard Sword...

Noodling around elsewhere in that site, I find that our uranium bastard/long-ish sword would weigh about as much as a two-handed sword, so it would definitely be wieldable, it would just be a bit short for normal two-handed maneuvers and tactics.

I also see that I screwed up one of the links in my earlier post. The source asserting uranium as the second hardest common metal is here (http://www.eoslifework.co.uk/pdfs/DU2102A3a.pdf).

Kinthalis

02-05-2004, 03:43 PM

Well a great sword can weigh from 5 to 8 lbs, so yes, it would come in at the top of the scale there. BUT the reason such weapons are easily wielded is due to their point of balance and blade shape.

That much weight on a smaller sword might make it unwieldly even if it does weigh the same as a greatsword. Most likely the blade geometry and shape, probably the whole design would have to change.

smiling bandit

02-05-2004, 04:44 PM

Nit pick - that's a longsword.

I assure you a 3ft 8inch sword is well into the Hand-and-a-half range unless you're Shaqile O'Neil.

Kinthalis

02-05-2004, 05:09 PM

Ranchoth

02-06-2004, 02:18 AM

The real question is how effective we want this thing to be as a sword. Is the protagonist going to be regularly engaging in heavy swordfights, or is he just going to draw it and everyone cowers in fear?

I'd envisioned the sword—well, swords, for a reactor—as being something like a holy or royal relic (kind of like the Sword of Temporal Justice (http://www.muppetlabs.com/~deadman/gallery/tower_of_london_feb_2003/p0000700) or it's siblings, held in the Tower of London) It wouldn't be the hero's normal sword, just one that he was ferrying from one place to another. Though he might draw it to use in combat in a a desperate situation—like if he was caught off guard, without his own sword. Or even if he wanted to make a point of overawing someone. But he wouldn't even know was radiation was, much less that that was the danger the sword presented.

And, that being said...could a special shielded (with Lead, or maybe even Gold? (http://boards.straightdope.com/sdmb/showthread.php?p=3016147&highlight=gold+lead+radiation#post3016147)) scabbard to keep the Uranium sword in, to help protect one from the radiation? Or would a scabbard built hefty enough to provide meaningful radiation protection just be too heavy to carry?

And Cervaise, koeeoaddi? Double amen to that. Triple, even. Thanks for the replies, all!

smiling bandit

02-06-2004, 06:36 AM

Hence, why it is a longsword.

Longsword (langeschwert, spadalonga, etc) is a long blade with a full hilt that accomodates two hands.

The bastard sword is smaller and usually posseses a hilt that accomodates 1 and a half hands It's a tight fit for two-hands. It's basically an arming sword for either 1 or two-hands. Usually the blade tapers sharply into a point at the end.

You might be getting your definition of 'longsword' from D&D or role-playing.

No, there is no such real thing as a "longsword". I have found no contemporary account in Europe that anywhere describes a longsword. And modern commentary is decidedly mixed. That particular length is built such that it could be swung by one hand, if I understand correctly, but it's designed to be used by two for most people. Which is the definition of a bastard sword. The specific length of the hilt is irrelevant - ones intended for use in battle would probably have been built for a given user, anyway. There is no absolute gospel about swords.

Desmostylus

02-06-2004, 07:16 AM

No, there is no such real thing as a "longsword". I have found no contemporary account in Europe that anywhere describes a longsword. [Enter CAPULET in his gown, and LADY CAPULET]

CAPULET: What noise is this? Give me my long sword, ho!;)

----------

Kinthalis

02-06-2004, 07:48 AM

No, there is no such real thing as a "longsword".
[QUOTE]

Incorrect. The term was commonly used to describe the weapon I mentioned during the middle ages and the renaissance by fencing masters during these periods. I'm tempted to say master Lichteneur and Ringeck and all the others knew what they were talking about.

It is true that through out time the term was applied to any weapon with a long blade. The Roman's calvary sword (very basically a larger version of the gladius hispanicus) were termed 'longswords'.

[QUOTE]
I have found no contemporary account in Europe that anywhere describes a longsword.

Then you are not looking hard enough. In my studies as a historicla fencer I've come accross the term (Spadalonga, langeschwert, etc) many a times. I have trained to use the weapon, I'd be very embarrassed if I couldn't even use the correct term for it.

That particular length is built such that it could be swung by one hand, if I understand correctly, but it's designed to be used by two for most people. Which is the definition of a bastard sword. The specific length of the hilt is irrelevant - ones intended for use in battle would probably have been built for a given user, anyway. There is no absolute gospel about swords.

It is true that swords varied widely in design and length as well as other factors were sometimes tailored to the intended user. But the general terms for these weapon still applies as a way to identify them, their method of use, and their purpose on the battlefield.

A longsword, as I explained (and is pictured here: http://www.schwertkampf-ochs.de/willkommen.html) are well defined in the fechtbuchs or fencing manuals of the high middle ages. The sword was used two-handed but could also be used one-handed when mounted.

Here's an exmaple of a bastard sword: http://www.armor.com/2000/catalog/item081.html Notice the blade shape, and the hilt, which accomodates 1 hand and a half.