Massive Particle Accelerator Revving Up : Energy Technology - Page 3

Massive Particle Accelerator Revving Up

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Re: Massive Particle Accelerator Revving Up

by Tanada » Tue 17 Apr 2007, 06:29:34

$this->bbcode_second_pass_quote('Rock_solid_bacon', 'A')ctually, the longhairs GUESSED that lithium 6 (rare) would make the reaction so they tried to separate lithium 7 and lithium six. the ruskies built a billion dollar plant top make lithium 6 isotope so they could make a fusion bomb.
Military longhairs ran out of 6 (hard to separate) so they said WHAT IF we just use hnatural lithium 7?

they did and it put out THREE times the energy as lithium 6.
Because lithium 7 breaks down into TWO tritium molecules! WOW.
now you have deuterium tritium fusion, and it put out 15 megatons instead of expected 4.8 megatons

it wiped the island off the map and exposed inhabited islands hundreds of miles away to deadly doses of readiatiinn and the army personel on the monitoring island were overcome by the mushroom cloud which was 100 miles wide, they hid in the basement until they could be rescued.

In other words COMMON LITHIUM 7 right out tof the ground is way more explosive than lithium 6 isotope which the Ruskies worked on for months to separate!

too interesting.

In reality when you bombard Li-7 with neutrons you get one He-4 and one H-3(aka Tritium), you do not get $this->bbcode_second_pass_quote('', 'T')WO tritium molecules

that would be (4) H-3 bound together in two pairs. They always knew that you could get a Li-7+H-1 reaction, the error was in calculating the threshold energy needed to overcome the coulomb barrier. The orriginal plan was to use Li-6+H-2 as the solid fuel, more or less as you stated, however the reason they did that was because Li-6 breaks into H-3 easier than Li-7 does. The plan was split Li-6 into H-3 and fuse the H-3 and H-2 to make He-4 and a lot of energy plus free neutrons. There was no plan to fuse Li-6 or Li-7 directly, hence the surprise when the Li-7 fused with the H-1 it was carrying for stabillity.

All if this information is availible in the open literature, particularly in the book US Nuclear Weapons: The Secret History by Chuck Hanson Book or from his website Website

$this->bbcode_second_pass_quote('Alfred Tennyson', 'W')e are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.

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Re: Massive Particle Accelerator Revving Up

by EnergyUnlimited » Tue 17 Apr 2007, 07:16:21

$this->bbcode_second_pass_quote('Tanada', 'T')here was no plan to fuse Li-6 or Li-7 directly, hence the surprise when the Li-7 fused with the H-1 it was carrying for stabillity.

If all that is true, why our nuke designers still bother with tritium?
It is inconvenient (needs replacing every few years), expensive to make etc.
On the other hand relatively common chemical, lithium hydride worth something like $25/kg could make far better fusion explosive and should work nicely, once heated sufficiently with fission primer.
Fusion of such a fuel also appear clean as only 4-He is formed.
Can you comment on that?

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Re: Massive Particle Accelerator Revving Up

by Tanada » Tue 17 Apr 2007, 08:03:13

$this->bbcode_second_pass_quote('EnergyUnlimited', '')$this->bbcode_second_pass_quote('Tanada', 'T')here was no plan to fuse Li-6 or Li-7 directly, hence the surprise when the Li-7 fused with the H-1 it was carrying for stabillity.

Seems how you ask and I actually know the answer here we go.

Lithium hydride is the fusion fuel of an H-bomb, tritium is the booster fuel in the fission trigger for the H-bomb. If that is clear as mud here is what it boils down too. The H-bomb is actually two or more distinct stages of weapon, the first stage is a fission bomb to heat and compress the fusion stage 2. Fission bombs to be efficient need to be compressed as far as possible by implosion with high explosives. The best way to do that is to machine the fissionable material into a hollow sphere or cylinder because the implosive inertia will cause a larger effect than straight crushing impact on a solid target. Back in the late 1940's they figured out that if the sphere is hollow anyhow you can inject a few grams of Tritium into the sphere right before the explosives crush it. The Tritium is now in the center of a very highly compressed fissionable mass. When the compression reaches maximum density an external neutron source injects a few hundred neutrons to start the chain reaction. Within 30 nanoseconds from initiation of fission the fissionable mass expands out too far for fission to continue, but in those 30 nanoseconds an extreamly rapid series of events takes place. As the first fissions start they rapidly spread, doubling in number in a few nanoseconds. In turn this releases heat on a scale unseen except in the sores of supernova stars, so hot that the Tritium easily fuses early on in the fission process. As each pair of tritium atoms fuse they in turn release two high energy neutrons that add to the doubling rate of the fission reaction. The reactions go on simultaneously to the extent that the fission energy yeild for a boosted weapon is 4 to 8 times as great as it would be without the tritium.

Energy and neutrons from the fission first stage compress and initiate the fusion second stage which is actually a mass of Lithium hydroxide with a shell of Uranium on the outside and a pencil like shaft of Plutonium on the inside. As the uranium pusher crushes the lithium hydroxide onto the plutonium pencil from the heat of the fission first stage neutrons escaping the first stage initiate fission in the plutonium pencil. The plutonium fission heats the lithium hydroxide while also releasing neutrons. These fission neutrons impact Li-6 nuclei in the lithium hydroxide releasing tritium, which fuses with the deterium present in the Li-6+H-2 molecules releasing more energy and neutrons. Some of these neutrons release more Tritium from the Li-6, some cause increased fission in the Plutonum pencil, and some cause fission in the Uranium pusher. As all three sources of energy increase the temperature and pressure in the second stage the Li-7+H-1 also begins to undergo fusion resulting in Be-8=(2)He-4and even more energy. The reaction is synergistic, all four sources reinforce and boost each other.

The higher the compression for each stage the more time it takes for the energy produced to overcome inertia and stop the reaction. Each successive stage is releases roughly nine times as much energy as the stage immedietly preceeding it in the chain. By boosting the fission trigger 400% with Tritium you therefore get an increased yeild of 3600% from the second stage. You can have an arbitrary number of stages as you choose, the largest weapons ever tested were three stages and at that level you can get 100 to 200 Megatons TNT equivelent. A four stage weapon could therefor easily reach 900-1800 Megatons, about the same as a minor asteroid impact. With five stages you could duplicate Chixilube in the Yucatan which is suspected of wiping out the dinosaurs. Hopefully nobody will ever be that stupid.

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Re: Massive Particle Accelerator Revving Up

by EnergyUnlimited » Wed 18 Apr 2007, 03:07:20

$this->bbcode_second_pass_quote('Tanada', 'S')eems how you ask and I actually know the answer here we go.

Many thanks for your "introduction to nuclear weapons" primer.
It was interesting to read.
Now I do understand, that tritium comes handy there, however it may not be critical.
What if tritium booster is ommited?
Would it be still possible for crap, non boosted fission stage to generate sufficient temperatures to set off fusion stage, which could ignite further fusion stage etc?
Or maybe initial fission stage would fail to deliver enoug energy and fusion would fail to ignite alltogether?

$this->bbcode_second_pass_quote('', 'F')ission bombs to be efficient need to be compressed as far as possible by implosion with high explosives. The best way to do that is to machine the fissionable material into a hollow sphere or cylinder because the implosive inertia will cause a larger effect than straight crushing impact on a solid target.

I accept this reasoning, but with plutonium we can also help ourself with delta-to-alpha plutonium transition. there is significant (25%, if I remember well) density increase there.
$this->bbcode_second_pass_quote('', 'B')ack in the late 1940's they figured out that if the sphere is hollow anyhow you can inject a few grams of Tritium into the sphere right before the explosives crush it. The Tritium is now in the center of a very highly compressed fissionable mass.

Why not to insert a small ball of lithium-6 tritide into geometrical centre of Pu hollow sphere, instead of pumping gas in for simplicity reasons?
Why not to collapse sphere made of Plutonium or Uranium-235 tritide (both metals are forming easily compounds with hydrogen)?
one could probably get neat design with good boosting by doing so.

$this->bbcode_second_pass_quote('', 'W')hen the compression reaches maximum density an external neutron source injects a few hundred neutrons to start the chain reaction.

Why do they use external neutron sources (Polonium-Beryllium?) with Pu?
There is enough of free neutrons in weapons grade Pu (and even more in reactor grade...) to set off fission regardless. For that reason gun design is unsuitable with Pu weapons.
Even U-235 would have enough free neutrons to set business going...
My suspicion is that they do it to increase yield, are there any other reasons?
NB. Polonium-Beryllium neutron sources. I had red somewhere that nearly all early weapons workers absorbed harmful amounts of 210-Po. It was apparently impossible to prevent that.

$this->bbcode_second_pass_quote('', 'W')ithin 30 nanoseconds from initiation of fission the fissionable mass expands out too far for fission to continue, but in those 30 nanoseconds an extreamly rapid series of events takes place.
I was believing that this stage takes about microsecond, but you corrected me.

$this->bbcode_second_pass_quote('', 'A')s the first fissions start they rapidly spread, doubling in number in a few nanoseconds. In turn this releases heat on a scale unseen except in the sores of supernova stars, so hot that the Tritium easily fuses early on in the fission process.
That is surprising. In cores of supernovas quark soup is probably forming. It is hard to believe, that fission is so violent event.
In any case it is rather electric, than nuclear event, if you look on actual physics.
Did they calculate peak temperatures in fission cores?
How high these temperatures could be?
$this->bbcode_second_pass_quote('', 'E')nergy and neutrons from the fission first stage compress and initiate the fusion second stage which is actually a mass of Lithium hydroxide with a shell of Uranium on the outside and a pencil like shaft of Plutonium on the inside. As the uranium pusher crushes the lithium hydroxide onto the plutonium pencil from the heat of the fission first stage neutrons escaping the first stage initiate fission in the plutonium pencil.
This Pu "pencil" is critical part of Ulam-Teller design.
On the other hand uranium casing is not. Largest bomb ever detonated by Soviets (50Mt) was free of uranium casing to reduce fall-out.
97% of energy came out of fusion there.
$this->bbcode_second_pass_quote('', 'Y')ou can have an arbitrary number of stages as you choose, the largest weapons ever tested were three stages and at that level you can get 100 to 200 Megatons TNT equivelent. A four stage weapon could therefor easily reach 900-1800 Megatons, about the same as a minor asteroid impact. With five stages you could duplicate Chixilube in the Yucatan which is suspected of wiping out the dinosaurs. Hopefully nobody will ever be that stupid.
Some cynical peoples are suggesting, that something like 6-7 stages warhead with few thousands tons of thermonuclear explosives, humble lithium hydride comes to mind as major component of that... is installed right under Pentagon.
It would be detonated once US had realised that it is losing atomic war...
I don't believe in those gossips, but who knows?

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Re: Massive Particle Accelerator Revving Up

by Tanada » Wed 18 Apr 2007, 06:35:28

$this->bbcode_second_pass_quote('EnergyUnlimited', '')$this->bbcode_second_pass_quote('Tanada', 'S')eems how you ask and I actually know the answer here we go.

You pretty much summed it up, if the fission trigger doesn't produce the needed minimum energy to ignite the fusion burn the weapon is called a 'fizzle'. The first fusion test done by the United States used unboosted Fission primaries to ignite the fusion fuel, however up until the 1990's fissionable material was treated as a rare and precious resource and US weapons were designed to use as little as possible. $this->bbcode_second_pass_quote('', '
')

$this->bbcode_second_pass_quote('', 'F')ission bombs to be efficient need to be compressed as far as possible by implosion with high explosives. The best way to do that is to machine the fissionable material into a hollow sphere or cylinder because the implosive inertia will cause a larger effect than straight crushing impact on a solid target.

I accept this reasoning, but with plutonium we can also help ourself with delta-to-alpha plutonium transition. there is significant (25%, if I remember well) density increase there.

Compared to explosive implosion the phase change rate for Plutonium is not a significant factor in the ultimate density at full compression. Plutonium is the only known material with 6 phase changes in density IIRC dependent upon temperature.
$this->bbcode_second_pass_quote('', '
')
$this->bbcode_second_pass_quote('', 'B')ack in the late 1940's they figured out that if the sphere is hollow anyhow you can inject a few grams of Tritium into the sphere right before the explosives crush it. The Tritium is now in the center of a very highly compressed fissionable mass.
Why not to insert a small ball of lithium-6 tritide into geometrical centre of Pu hollow sphere, instead of pumping gas in for simplicity reasons?
Why not to collapse sphere made of Plutonium or Uranium-235 tritide (both metals are forming easily compounds with hydrogen)?
one could probably get neat design with good boosting by doing so.

That's an easy one to answer, if you make the sphere of Plutonium or Uranium tritide you face two problems, firstly it doesn't compress as well and secondly the Tritium undergoes beta decay over time. In as little as three years the Tritium decay becomes a major factor because when it decays it becomes He-3, which is a neutron absorber as well as being chemically inert. This both breaks the chemical bonds between the fissionable material and the tritium it also has the opposite effect during the implosion of both reducing the ultimate compression and robbing the reaction of neutrons. By placing the Tritium in a seperate fuel charge tank it is simple and easy to switch out the tritium every year or so to be purified. To do that with a fissionable mass chemically combined with the Tritium you would have to take all the mass out for remanufacturing.

As for the Li-6+H-3 small sphere in the very core of the weapon you have two issues. First same as above the Tritium will decay and He-3 will build up requiring extraction and remanufacturing, second by using pure H-3 you get two high energy neutrons per fusion event, if you use Li-6+H-3 you get less because the Lit-6 has to be struck by a neutron before it releases Tritium to fuel the reaction.

$this->bbcode_second_pass_quote('', '
')
$this->bbcode_second_pass_quote('', 'W')hen the compression reaches maximum density an external neutron source injects a few hundred neutrons to start the chain reaction.
Why do they use external neutron sources (Polonium-Beryllium?) with Pu?
There is enough of free neutrons in weapons grade Pu (and even more in reactor grade...) to set off fission regardless. For that reason gun design is unsuitable with Pu weapons.
Even U-235 would have enough free neutrons to set business going...
My suspicion is that they do it to increase yield, are there any other reasons?
NB. Polonium-Beryllium neutron sources. I had red somewhere that nearly all early weapons workers absorbed harmful amounts of 210-Po. It was apparently impossible to prevent that.

Testing back in the early years of nuclear technology demonstrated that while fission does result from compression without a neutron source on average the yield was half or less than with a neutron initiator. The reason for this is pretty basic, the reaction time is so short that with criticallity initiated fission the mass is rebounding outward from the implosion before the rate builds up enough to yeaild well. Each fission generation yields twice what the preceding generation yielded, loosing just the last generation reduces your yeild by half, loosing two generations cuts yeild by 75% and so on. Timing therefore becomes critical, to get the best possible yield you need the reaction to start at exactly the nanosecond of maximum density, if it starts sooner the fission energy will overcome inertia too soon and you loose a generation or two of fission, if it falls too late the same thing happens.

The reason weapon designers shudder at using reactor grade plutonium is all about predetonation, initiation occurs before maximum compression can be obtained. For a terrorist with a large mass to play with this can be an advantage, no seperate initiator is needed and with enough Plutonium you overcome the predetonation losses. It isn't elegant engineering, it just works.

Po-Be sources stopped being used around the beginning of the Korean War, because the Po-210 is so highly radioactive they had to be changed out frequently just like the Tritium capsuals are today, they were expensive, and worst of all they relied upon mechanical crushing to release large quantities of neutrons so they were not perfectly suited to initiation at maximum compression. As soon as the crushing hit the critical threshold they began releasing neutrons so if you used them it set an arbitrary limit on how much compression your weapon could acheive before detonation effects took over the reaction. An external initiator is just a miniature particle accellerator that fires Deuterium at a target mass, usually Berylium. It operates in a very precise manner allowing exact timing for the flood of neutrons to initiate fission at the moment of max compression.

$this->bbcode_second_pass_quote('', '
')

$this->bbcode_second_pass_quote('', 'W')ithin 30 nanoseconds from initiation of fission the fissionable mass expands out too far for fission to continue, but in those 30 nanoseconds an extreamly rapid series of events takes place.
I was believing that this stage takes about microsecond, but you corrected me.

$this->bbcode_second_pass_quote('', 'A')s the first fissions start they rapidly spread, doubling in number in a few nanoseconds. In turn this releases heat on a scale unseen except in the cores of supernova stars, so hot that the Tritium easily fuses early on in the fission process.
That is surprising. In cores of supernovas quark soup is probably forming. It is hard to believe, that fission is so violent event.
In any case it is rather electric, than nuclear event, if you look on actual physics.
Did they calculate peak temperatures in fission cores?
How high these temperatures could be?

Yes they have calculated peak temperatures and so on, but I have not seen those numbers in a long time and do not rememeber exactly. Commonly thrown around phrases are hotter than a supernova core and smaller than an asprin meaning that in about on cc of space you have a spot hotter than anything else in the Universe, but of course it only stays that way for an instant.
$this->bbcode_second_pass_quote('', '
')
$this->bbcode_second_pass_quote('', 'E')nergy and neutrons from the fission first stage compress and initiate the fusion second stage which is actually a mass of Lithium hydroxide with a shell of Uranium on the outside and a pencil like shaft of Plutonium on the inside. As the uranium pusher crushes the lithium hydroxide onto the plutonium pencil from the heat of the fission first stage neutrons escaping the first stage initiate fission in the plutonium pencil.
This Pu "pencil" is critical part of Ulam-Teller design.
On the other hand uranium casing is not. Largest bomb ever detonated by Soviets (50Mt) was free of uranium casing to reduce fall-out.
97% of energy came out of fusion there.

Tsar Bomba was designed to use Uranium pushers in the fusion stages, in the end the Soviets decided it might not be prudent and wasn't nessecery to prove the design worked so they eliminated the Uranium pusher from the third stage and substituted lead. The original design and the one deployed would have yielded 150-200 MT if the third stage had used a Uranium pusher because the reaction would have reinforced itself instead of just igniting the Fusion burn.

Certainly you can make the pusher mass non-fissionable as the Soviests did for the Tsar Bomba test you cite above, doing so however greatly reduces your ultimate yield or "bang for the buck"
One of the earliest fusion desgins was to take a plain fission weapon like the Fat Man dropped on Nagasaki and put a well insulated tank full of liquid Deuterium around it. It was big, it was bulky, and it was complicated, but it worked. Doing it that way you can just increase the size of the tank to increase the size of the burn so if you are using a ground station at least in theory you can do away with staging.
$this->bbcode_second_pass_quote('', '
')
$this->bbcode_second_pass_quote('', 'Y')ou can have an arbitrary number of stages as you choose, the largest weapons ever tested were three stages and at that level you can get 100 to 200 Megatons TNT equivelent. A four stage weapon could therefor easily reach 900-1800 Megatons, about the same as a minor asteroid impact. With five stages you could duplicate Chixilube in the Yucatan which is suspected of wiping out the dinosaurs. Hopefully nobody will ever be that stupid.
Some cynical peoples are suggesting, that something like 6-7 stages warhead with few thousands tons of thermonuclear explosives, humble lithium hydride comes to mind as major component of that... is installed right under Pentagon.
It would be detonated once US had realised that it is losing atomic war...
I don't believe in those gossips, but who knows?

Same scenario as the movie Dr. Strangelove about the Soviets setting up a device like that linked to detectors all over their empire. If the detectors discovered a sneak attack they would detonate the planet buster and wipe out life on Earth.
Dr. Strangelove

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