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View Full Version : Can the Hoover dam withstand a nuclear blast?


03-27-1999, 05:26 PM
My buddy, a phd. in Chemistry says so. In a way it makes sense, it withstands an incredible amount of water pressure, but I am not so sure. I don't recommend an empirical test. If a blast could destroy it, where would it have to explode.

03-27-1999, 10:37 PM
It all depends on how large a bomb you got. To do the job with a Hiroshima or Nagasaki type bomb you would certainly have to bury it somewhere within the dam itself and have people with same skills as those demolition experts who bring down Las Vegas Hotels with a couple hundred pounds of dynamite.

Keep in mind that those early A-bombs were fire crakers compared to what we have today. You're Phd. buddy must know of some universal law that prohibits the ability to build nuclear bombs beyond a certain yeild. Given enough fissionable material you could blow up the whole solar system, dams and all.

03-27-1999, 11:12 PM
I seem to recall from "Dark Sun : The Making of the Hydrogen Bomb" by Richard Rhodes, that there was a limit to the size of a fission bomb. I don't remember why, if it was explained.

However, I think there's no limit to the size of a hydrogen/fusion bomb.

-- Revtim

03-28-1999, 03:58 PM
I'm no physicist, as will be obvious shortly. But, the limit on the size of a fission bomb is related to the difficulty in keeping the fissile material compressed long enough for the chain reaction to occur.

This was a problem even in the first atomic bombs. What happens if you put enough fissile material together to explode is that as the chain reaction ramps up, the material will blow itself apart before achieving a totally involved chain reaction. I believe they referred to such things as squib explosions. Anyway, to counteract this problem they have to do a variety of things.

First, they use conventional explosives to compress the material long enough for the big kaboom to occur. The Hiroshima bomb used a modified naval gun to shoot half of the mass at the other half and thus compress the fissile material long enough. The Trinity and Nagasaki bombs used shaped explosives to implode a sphere made of plutonium.

The Trinity and Nagasaki bombs also had neutron emitting devices at their center which were made of some rare elements which I don't remember. These neutron enhancers were triggered with the explosion, The idea was to get the free neutron count up more quickly so that the kaboom could occur before the mass blew itself apart. This is the same type of technology that has been refined to produce the smaller warheads we have been hearing about in the news lately.

I am sure that all of this boils down to a maximum size for a critical mass based on the distance a neutron can travel before things get out of hand.

I would love to hear someone knowledgeable give us a few details on this topic.


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The Trustworthy Troglodyte

03-28-1999, 06:22 PM
I'm sure that at some point, weight would get to be a factor. Uranium and Plutonium are quite heavy. At some science center somewhere they had a display in which you could attempt to lift various metal cylinders, maybe 3" across by 2" high or so. They had Aluminum, Steel, and spent Uranium. The first two were no problem, but the last was was unGodly heavy! That little cylinder had to weigh over 50 pounds! If you tried to build too big a nuclear warhead, it would probably be almost impossable to make it fly, due to shear weight of the fissionable material.

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"I had a feeling that in Hell there would be mushrooms." -The Secret of Monkey Island

03-29-1999, 12:00 AM
Sure, such a thing could blow a hole in it. Depends how you do it. IF you put a firecracker in your hand and light it, youll get a big surprise but your hand would be okay. However, if you close your fist on it, well,your hand won't be okay, you get the point. Kablooie!

Also, if you visit a patent library, like the one at UCSD, you can get all the patents necessary to make any kind of A, H or whatever Bomb you fancy!. I know, I did it once in the 70's. My librarian said she sure WOULDN'T show me how to find them patents. lol

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03-29-1999, 12:05 AM
I hope Dread Pirate Judy never sees this thread.



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Ranger Jeff
The Idol of American Youth

03-29-1999, 02:22 AM
According to one Cecil Adams, if the Russians set off the largest nuke they claimed to have, it would create a crater 19 miles in diameter. Hoover Dam would be gone.

The water does create a great deal of pressure on Hoover Dam, but it is relativly static pressure. A bomb blast, and it doesn't even have to be an atomic blast, could easily take out the dam if properly placed.

Look at anti tank weapons for instance. Insted of building bigger bombs in anti-tank warefare, they built smaller shaped charges (HEAT and HESH rounds)to cause specific pressure patterns to appear, breaching the tank defenses. You could do a similar thing with a dam.

As for where to place the bomb, it would be best to place it at the bottom of the inside (water filled side) of the dam in the middle as that's the watter pressure is the strongest. That's probably where the dam is strongest too, but without a detailed blueprint, you're not getting a better answer than that.

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Jim Petty
A Snappy message should appear here

03-29-1999, 11:48 AM
Yes, that would be right Jim.

I can just see the people running that place right now coming into the forum and squirming.

03-29-1999, 01:34 PM
Although the temperature at the center of the Hirosima explosion may have been enough to vaporize concrete it never had a chance. Nuclear tactical doctrine has always held that for greatest effect a bomb should be detonated several hundred or even thousand feet above the target so as to maximize the effect of the blast (ie spread the distruction over a larger area). The first A-Bomb test in New Mexico was a detonation at about 200 feet and still managed to melt some of the desert sand beneath it (sand and concrete are both made mostly of silica).

My guess is that if you removed the blast from the equation and tried to vaporize Hoover dam with just the heat of a Hiroshima bomb all you'd manage to do is melt a few inches of the exterior. If an analogy can be made to pottery kilns, this might make the dam even sturdier.

03-29-1999, 01:44 PM
Hmmmm the delivery system would definately make a difference. For example we currently have many types of smart bombs and guided missles for cracking intelligence bunkers capable of traveling through many feet of reinforced concrete. With this method the warhead, even a small warhead, would detonate INSIDE the structure of the dam. Might make a difference. I kinda like the pottery analogy.

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You can fool all of the computers some of the time.

03-29-1999, 01:44 PM
Also, if you visit a patent library, like the one at UCSD, you can get all the
patents necessary to make any kind of A, H or whatever Bomb you fancy!. I
know, I did it once in the 70's. My librarian said she sure WOULDN'T show me
how to find them patents. lol


Speaking as a librarian, it's none of her business what you're looking for. If you want something that's in a published government document, BY LAW, they have to help you.

However, a librarian doesn't have to engage in legal research for someone (and is not supposed to), so she could have used that rationale. A patent search is considered legal research.

03-29-1999, 02:12 PM
even the smallest of nukes, in a groundburst would take out any manmade structure on the surface, and in a radius. the hiroshima and Nagasaki blast were air bursts at thousands (I don't remember exact number) of feet. Air bursts maximize area of damage because the ground absorbs/deflects less of the effect. I would suggest placing the device on the open side of the dam at range.The overpressure "blast" of any exloplosion is expressed as Psi even at several miles the smallest nucear bomb puts out alot of pressure. How many square inches does that great big dam have. if one put great force on the dam towards the contsant pressure of the water it would then flex back and be torn to shreds.
if you put the device in the lake you lose have the fun as a great deal of the energy would be lost to the lake bed and water.
I've got the krytons, who's got some enriched Pu? let's build this thing!!!! <g>

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&lt;insert witty sig here&gt;

03-29-1999, 03:58 PM
As to where to place the bomb, I have a small observation. I remember reading about the Dambuster missions that the English ran during WWII. Part of the strategy was to detonate the damn underwater on the deep side so that the water itself would compress the blast. The rotating bombs were dropped, and they skipped across the water till they hit the dam and then sank. The bomb was triggered by a pressure sensitive device when the bomb got to a certain depth that I remember was somewhere above the bottom.

I guess part of the answer to the question depends on the defintion of "withstand". If that means "vaporize", I'm not sure what the answer is. If it mean "put the sucker out of service", as was the allied goal in WWII, it seems almost unquestionalbe that it would work. They weren't Hoover dams, but the ones on the Ruhr were pretty substantial and they were taken out with about 2,000 pounds of conventional high explosive.

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The Trustworthy Troglodyte

03-29-1999, 04:18 PM
If an analogy can be made to pottery kilns, this might make the dam even sturdier.

I'm not sure that's a good analogy. Clay is a homogenious (or pretty much) substance made of very small particles. Concrete is an mixture of larger particles of several different minerals, some of which are baked in the manufacturing process.

03-30-1999, 12:24 AM
[QUOTE]
As for where to place the bomb, it would be best to place it at the bottom of the inside (water filled side) of the dam in the middle as that's the watter pressure is the strongest. That's probably where the dam is strongest too, but without a detailed blueprint, you're not getting a better answer than that.
[\QUOTE]

I would have guessed the best place to put the bomb would have been on the outside, since the dam was not built to withstand any significant pressure from that side. But that's just a guess.

One factor that this thread has ignored is the incredible heat. Wouldn't the heat alone be enough to vaporize the concrete? Or does concrete simple not vaporize at the temperatures involved? What happened in Hiroshima, was all the damage at ground zero to concrete structures due to the blast, and not the heat?

-- Revtim

03-31-1999, 12:05 AM
if you put the device in the lake you lose have the fun as a great deal of the energy would be lost to the lake bed and water.
Actually, watter transmits shock waves much better than air does, because of its greater density.


I'm reminded of a video I saw in a physics class, where a smallish TNT bomb was placed at one end of a swimming pool, and a 5-gallon glass bottle at the other. When the bomb was set off, the bottle blew apart. When the experiment was duplicated in an empty pool of the same size, the bottle was unaffected.


Water does absorb radiation very well, so a nuke's "flash" might be greatly lessened, but I don't think it would have all that much effect on concrete anyway (unless it was intense enough to vaporise it entirely). Come to think of it though, the radiation would flash-boil one hell of a lot of water, and that would make a serious blast effect of its own.

04-13-1999, 10:03 AM
Drop a SUBROC...they're nuclear tipped torpedos, designed to flatten submarines (or sub groups). Submarines have an intense disadvantage, since even with the titanium hull of the Russian Alfa-class, normal torpedo explosions tend to cause a great deal of grief (hence why US Submarine technology has been based on *avoiding* torpedos more than withstanding them)

What does that have to do with a dam? The WWII dam busters were 1000 lb of explosives that were made to sink and explode near the base of the dam...they split the dams pretty easily. Magnify that by about 500-5000 (depending on size of bomb), and people several miles downstream will be picking pieces of Hoover Dam out of their house...

About the difference in medium: Water dampens the explosion a bit, but remember the weight difference between water and air. Getting hit by a 40 mph gust of wind isn't so bad, getting hit by a wave of water moving at 40 mph will knock you off your feet easily.

On the bright side: the heat factor of the explosion will lessen the floods a bit. On the down side, it'll be a bit balmy in the area for a while.

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Naggy

"I am an Anarchist. The reason I don't promote Anarchy is because I don't trust you idiots." -anon

Markxxx
08-23-1999, 06:02 AM
A situation occured where the dams upstream from Hoover appeared to give way. IF they had Hoover would've gone. So they wouldn't even have to blow up Hoover.

Israel apparently has kept Egypt in line more than once by threatening the Ansawm (sp??) Dam.

GregAtlanta
08-24-1999, 12:08 AM
Does it really matter whether the dam could withstand a nuclear blast? Isn't that sort of like asking whether your pants will still be nicely creased after a head-on collision?
"Well, we've been hit by a big-ass nuclear bomb and most everything's been incinerated. The unlucky few of us are sitting here watching our skin melt.
Uh-oh, here comes some water. That's going to ruin our day."
-- Greg, Atlanta
(Sorry to interrupt the scientific disucssion.)

Undead Dude
08-24-1999, 01:10 AM
As for where to place the bomb, it would be best to place it at the bottom of the inside (water filled side) of the dam in the middle as that's the watter pressure is the strongest. -- Jimpy
Well, just to be nit-picky, "the middle" would be irrelevant here, as water pressure is dependent on depth, but not position (or total water volume for that matter). So anywhere at the lowest depth would give you the best surrounding pressure.

The only logic in which I can actually see this survivability idea working is with the assumption that the attack would be from a normal cold war ICBM. It might survive an air burst, and a dam would represent a rather difficult target for a ground burst to hit. The accuracy of ICBMs is far poorer than some seem to think. :)

Of course the reservoir would be a pretty easy target, and a ground burst there might be enough anyway.