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blair.mitchelmore
2008-Nov-04, 09:27 PM
I registered here just to ask this question so hopefully someone knows.

So, the sun is a fusion reaction and nuclear bombs are fission reactions. What happens if you explode a nuclear bomb inside a fusion reaction or a fusion bomb inside a fission reaction? Anything spectacular or just more of the same with a little extra on the side?

Swift
2008-Nov-04, 09:48 PM
First, welcome to BAUT blair.mitchelmore.


What happens if you explode a nuclear bomb inside a fusion reaction
Humans have not yet developed a controlled fusion reactor, so I don't know. The only fusion reactions we run (on a big scale) are fusion bombs.

And exploding a fusion bomb on or in the Sun would be like a single water droplet in a huricane.


or a fusion bomb inside a fission reaction
I recall an article many (20+) years ago in Scientific American, during the height of the Cold War. They discussed what would happen if a nuclear bomb were exploded over a nuclear power plant - short answer: very bad. The explosion would spread all the radioactive material in the power plant into the fallout cloud, greatly increasing the amount and hazard of the fall-out. But as soon as you explode the bomb, the fission reaction in the powerplant stops.

Celestial Mechanic
2008-Nov-04, 09:52 PM
I registered here just to ask this question so hopefully someone knows.

So, the sun is a fusion reaction and nuclear bombs are fission reactions. What happens if you explode a nuclear bomb inside a fusion reaction or a fusion bomb inside a fission reaction? Anything spectacular or just more of the same with a little extra on the side?
More of the same. The "classic" hydrogen bomb was a fission-fusion-fission device. An initial fission reaction compressed a mixture of deuterium, tritium, and lithium which ignited a fusion reaction. The neutrons from both reactions in turn interacted with a U238 shell to form U239 which went through two quick beta decays to become Pu239 and neutrons reacting with that caused one last fission reaction. Whew!

One interesting thing I did not know about this design was that almost half of the explosive yield came from that last reaction.

The so-called "neutron bomb" (official euphemism: "reduced yield weapon") dispensed with the uranium shell (and some of the yield) in order to have more neutrons in the output. Lovely. :eek:

JustAFriend
2008-Nov-04, 10:10 PM
...and in case you're wondering 'could a country or terrorist explode a bomb on the Sun and doom us all',
remember that the BIGGEST bomb Man has ever exploded (http://nuclearweaponarchive.org/Russia/TsarBomba.html) only weighed 27tons
(probably only a few hundred pounds of fission material for the trigger?),
while the Sun converts matter to energy at the rate of a MILLION TONS per SECOND.
And has for billions of years.....

George
2008-Nov-04, 10:10 PM
So, the sun is a fusion reaction and nuclear bombs are fission reactions. The original nuclear bombs were often called Atomic, or Atom, bombs and were strictly fission bombs (Uranium and plutonium). Fussion bombs have been called thermonuclear bombs or Hydrogen bombs (H-bombs, too).

There is a rumor that the Sun would appear entirely white if a thermonuclear bomb were exploded on its surface. :whistle: [This is an inside joke.]

PraedSt
2008-Nov-04, 10:12 PM
More of the same. The "classic" hydrogen bomb was a fission-fusion-fission device.

I didn't know that. I'd always thought fission-fusion. Thanks Celestial.

kleindoofy
2008-Nov-04, 10:57 PM
... There is a rumor that the Sun would appear entirely white if a thermonuclear bomb were exploded on its surface. :whistle: ...

[slightly off topic]

That same rumor applies to me: if I drink a glass of orange juice on thursday morning, the Sun appears entirely white.

It works with apple juice too. ;)

[/slightly off topic]

JMV
2008-Nov-05, 12:04 AM
More of the same. The "classic" hydrogen bomb was a fission-fusion-fission device. An initial fission reaction compressed a mixture of deuterium, tritium, and lithium which ignited a fusion reaction. The neutrons from both reactions in turn interacted with a U238 shell to form U239 which went through two quick beta decays to become Pu239 and neutrons reacting with that caused one last fission reaction. Whew!
It's not necessary for the U-238 to turn into plutonium in order to contribute to the fission yield in a fission-fusion-fission bomb. Fast neutrons produced by deuterium-tritium fusion have enough energy to cause fission of U-238 nuclei directly. And I think the U-239 and Np-239 have too long half-lifes to produce any significant amount of Pu-239 in the very short period of time during which the nuclear reactions are to take place in a thermonuclear weapon.

George
2008-Nov-05, 02:47 AM
[slightly off topic]

That same rumor applies to me: if I drink a glass of orange juice on thursday morning, the Sun appears entirely white.

It works with apple juice too. ;)

[/slightly off topic] The reason is clear, the caloric intake in these drinks is equivalent to a single nuclear blast at 1 A.U. ;)

Celestial Mechanic
2008-Nov-05, 04:55 AM
It's not necessary for the U-238 to turn into plutonium in order to contribute to the fission yield in a fission-fusion-fission bomb. Fast neutrons produced by deuterium-tritium fusion have enough energy to cause fission of U-238 nuclei directly. And I think the U-239 and Np-239 have too long half-lifes to produce any significant amount of Pu-239 in the very short period of time during which the nuclear reactions are to take place in a thermonuclear weapon.Thank you for the correction.

astromark
2008-Nov-05, 05:44 AM
In my attempt to simplify this to its most basic level I have left the complexities of nuclear physics out. The fact that we have used heavy metals and critical masses of such in order to extract a explosive event... a given. While the sun being mostly just hydrogen being converted by fission / fusion into helium. This is not helping you with your question.

" Originally Posted by blair.mitchelmore
I registered here just to ask this question so hopefully someone knows.

So, the sun is a fusion reaction and nuclear bombs are fission reactions. What happens if you explode a nuclear bomb inside a fusion reaction or a fusion bomb inside a fission reaction? Anything spectacular or just more of the same with a little extra on the side? "

Yes. that is about right. More of the same.
Understanding that solar activity is the result of pressure. A great deal of pressure. Where so much mass is present that molecular structure itself fails. The elements become fused and the energy released is just a buy product. All of the Earth could be consumed by Sol without so much as a blip on the screen. All of the nuclear energy available to humanity would not even be detectable if detonated inside of the sun all at the same moment. Not even a detectable hic-up.

thorkil2
2008-Nov-05, 08:49 AM
What no one seems to be noting here is that the whole idea is moot because it wouldn't be possible to deliver a fusion device to the sun intact. Solar fusion occurs deep inside the sun, so any device would vaporize and just add to the overall mass of the sun before you could achieve the explosive effect you are asking about. If the explosion is impossible, then the question is without meaning even if such an explosion would be significant (and it wouldn't be).

blair.mitchelmore
2008-Nov-07, 05:26 PM
thanks for the helpful responses, you've confirmed what I figured was the case. appreciate the input from people far more knowledgeable with this stuff.

John Mendenhall
2008-Nov-07, 05:40 PM
Understanding that solar activity is the result of pressure. A great deal of pressure. Where so much mass is present that molecular structure itself fails. The elements become fused and the energy released is just a buy product.



Astro, you're a little hazy on this. Along with the pressure, the temperature is critical to the reaction(s). And the reactions are nuclear, not molecular.

Regards, John M.

sabianq
2008-Nov-07, 05:55 PM
First, welcome to BAUT blair.mitchelmore.


Humans have not yet developed a controlled fusion reactor, so I don't know. The only fusion reactions we run (on a big scale) are fusion bombs.



actually, not quite true,
there are many fusion reactors that humans have developed that have sustained controlled fusion.

DIII-D (fusion reactor)
http://en.wikipedia.org/wiki/DIII-D

DIII-D is the name of a tokamak machine developed in the 1980s by General Atomics in San Diego, USA, as part of the ongoing effort to achieve magnetically confined fusion. DIII-D pioneered new technology including the use of beams of neutral particles to penetrate the confinement field of the device and heat the plasma within. It achieved several milestones including the highest plasma β parameter ever achieved at the time (early 1980s) and the highest neutron flux (fusion rate) ever achieved at the time

http://en.wikipedia.org/wiki/EAST
EAST (fusion Reactor)

The Experimental Advanced Superconducting Tokamak (EAST, internal designation HT-7U) is an experimental superconducting tokamak magnetic fusion energy reactor in Hefei,

Tokamak Fusion Test Reactor
http://en.wikipedia.org/wiki/TFTR

The Tokamak Fusion Test Reactor (TFTR) was an experimental tokamak fusion test reactor built at Princeton Plasma Physics Laboratory (in Princeton, New Jersey) circa 1980.


http://en.wikipedia.org/wiki/Joint_European_Torus
JET (fusion Reactor)

JET, the Joint European Torus, is the largest nuclear fusion experimental reactor yet built.

In 1997, JET produced a peak of 16.1 MW of fusion power (65% of input power), with fusion power of over 10 MW sustained for over 0.5 sec.

http://en.wikipedia.org/wiki/JT-60
JT-60 (fusion Reactor)

T-60 (JT stands for Japan Torus) is the flagship of Japan's magnetic fusion program, previously run by the Japan Atomic Energy Research Institute (JAERI) and currently run by the Japan Atomic Energy Agencys (JAEA) Naka Fusion Institute[1] in Ibaraki Prefecture, Japan. In operation since 1985, it currently holds the record for the highest value of the fusion triple product achieved. (1.77 \times 10^{28} K \cdot s \cdot m^{-3} = 1.53 \times 10^{21} keV \cdot s \cdot m^{-3})[1]

http://en.wikipedia.org/wiki/Tore_Supra
Tore Supra (fusion Reactor)

Tore Supra is a French tokamak that began operating after the discontinuation of TFR (Tokamak of Fontenay-aux-Roses) and of Petula (in Grenoble). Its name comes from the words torus and superconductor, as Tore Supra is the only one of the largest tokamaks to have superconducting toroidal magnets, allowing the creation of a strong permanent toroidal magnetic field.

http://en.wikipedia.org/wiki/T-15
T-15 (fusion Reactor)

The T-15 is a Russian (previously Soviet) nuclear fusion research reactor located at the Kurchatov Institute, based on the (Russian-invented) tokamak design. It was the first fusion reactor to use superconducting magnets to control the plasma.

granted,A half second is the longest controlled reaction, but it was controlled nevertheless.

and
http://www.space.com/missionlaunches/launches/fusion_rockets_000719.html


NASA constructs small-scale fusion reactor in what may be the first step towards building fusion rocket engines

George
2008-Nov-07, 05:58 PM
granted, A half second is the longest controlled reaction, but it was controlled nevertheless. That is not the control implied. A controlled bull ride requires at least 8 seconds. :)

John Mendenhall
2008-Nov-07, 06:01 PM
Understanding that solar activity is the result of pressure. A great deal of pressure. Where so much mass is present that molecular structure itself fails. The elements become fused and the energy released is just a buy product.



Astro, you're a little hazy on this. Along with the pressure, the temperature is critical to the reaction(s). And the reactions are nuclear, not molecular.

Regards, John M.

Try here:

http://en.wikipedia.org/wiki/H-bomb

sabianq
2008-Nov-07, 06:04 PM
well, somebody here said,

Humans have not yet developed a controlled fusion reactor

and i just suggested that was not quite true.
and listed a couple of reactors that have been built by humans.

I would wonder how long of time the fusion reaction takes place during a Fission-fusion-fission detonation.

is it longer than 1/2 a second?

sabianq
2008-Nov-07, 06:31 PM
if you are interested,
you can see the scale of the energy released by the sun during a typical CME (coronal mass ejection) and compare it to our most powerful hydrogen bomb.

lets use (tons of TNT) as a measure stick.

according to here:
http://en.wikipedia.org/wiki/Nuclear_weapon_yield
all of our testing put together has yielded the equivilant 510,000 Kilotons of TNT

or 510 megatons of TNT just over 1/2 a gigaton.

so if we look at solar output here:
http://www.sciencebuddies.org/science-fair-projects/project_ideas/Astro_p021.shtml

"At over 1.4 million kilometers (869,919 miles) wide, the Sun contains 99.86 percent of the mass of the entire solar system: well over a million Earths could fit inside its bulk.
The total energy radiated by the Sun averages 383 billion trillion kilowatts, the equivalent of the energy generated by 100 billion tons of TNT exploding each and every second.


the sun outputs the equivalent 100 gigatons of energy every single second, which is about 200 times the energy of all of our nuclear testing put together.

a typical CME can output the equivalent a billion tons of TNT by themselves

http://www.exploratorium.edu/learning_studio/auroras/glossary.html

a sudden outburst of energy and matter from the Sun. Flares can release more energy than billions of tons of TNT (hydrogen bombs are measured in megatons: millions of tons!) in a matter of seconds or minutes.

so i would have to ask, would you think that exploding a nuclear bomb in the sun would make a difference?

mugaliens
2008-Nov-07, 06:32 PM
All of the nuclear energy available to humanity would not even be detectable if detonated inside of the sun all at the same moment. Not even a detectable hic-up.

Well, now, let's look at this...

First, nearly all nuclear weapons these days are two-stage fusion weapons, as they're "the most compact, scalable, and cost effective option once the necessary industrial infrastructure is built." Most of the energy comes from fission, not fusion. Even the 6-inch artillary shells can be 2-stagers.

I can only assume that whoever has enough of them lying around they're willing, and able, to lob one into the Sun, probably has the requisite industrial infrastructure.

The Sun converts more than 4 million tons of matter to energy each second. That's not like a 4 MT fusion weapon, as a weapon's yield is based on the equivalent energy released in terms of kT or MT of TNT. Rather, it's many, many orders of magnitude greater.

Thus, Astromark's emphasis that it's massive is an understatement.

But not detectible? Even a shout is detectible in a hurricane or tornado, and the S/N ratio is exceedingly small. The thing that makes it detectible is that it has a characteristic signature. Similarly, if a star's output never pings the thorium spectral absorption line (1), but someone explodes something that does, then it'll register, even though it's many orders of magnitude smaller.

(1) I know very little about spectral imaging of stars. I know a great deal about signals, noise ratios, and detecting signals well below the "noise floor." Base on my experience, I think it's doable.

Swift
2008-Nov-07, 06:40 PM
actually, not quite true,
there are many fusion reactors that humans have developed that have sustained controlled fusion.

Quite true, my bad. Just because they haven't reach the point of a net energy gain, doesn't mean they don't exist.

Ok, back to the OP, drop a nuclear bomb on one of the tokamak machines, what happens. I can't say I know for sure, but I suspect you destroy the machine. But I don't imagine it is any worse than what the bomb does by itself.

sabianq
2008-Nov-07, 07:06 PM
Quite true, my bad. Just because they haven't reach the point of a net energy gain, doesn't mean they don't exist.


they are getting very close,
I really cant wait to see fusion power as a major source of energy.
It is so cool that they are at least working on it!

sabianq
2008-Nov-07, 07:09 PM
Ok, back to the OP, drop a nuclear bomb on one of the tokamak machines, what happens. I can't say I know for sure, but I suspect you destroy the machine. But I don't imagine it is any worse than what the bomb does by itself.

I guess that would be like taking a stick of dynamite to a nitroglycerin pill,

probably wont to much but destroy the pill.

mugaliens
2008-Nov-07, 08:50 PM
I liken it to a freight locomotive squashing a fruit fly on the tracks, at which point the 480 wheels add their insult to the injury.

astromark
2008-Nov-10, 08:16 AM
John Mendenhall and Mugaliens
Senior Members... I except that with your knowledge of the subject you might be able to actually detect this little bang in the sun... for goodness sake look at what I said. look at the OP. Like farting at thunder... there are you happy now ?:(

Quote. "you're a little hazy on this. Along with the pressure, the temperature is critical to the reaction(s). And the reactions are nuclear, not molecular.
Regards, John M."

I object to being called 'hazy' I am well aware of the facts here. Are you ?
Gravity of the mass is the trigger mechanism of Stars. Yes that very gravity creates the density that builds the temperature to the point where your fission / fusion thingie happens... :) No mass sufficient, no bang.

John Mendenhall
2008-Nov-10, 05:32 PM
John Mendenhall and Mugaliens
Senior Members... I except that with your knowledge of the subject you might be able to actually detect this little bang in the sun... for goodness sake look at what I said. look at the OP. Like farting at thunder... there are you happy now ?:(

Quote. "you're a little hazy on this. Along with the pressure, the temperature is critical to the reaction(s). And the reactions are nuclear, not molecular.
Regards, John M."

I object to being called 'hazy' I am well aware of the facts here. Are you ?
Gravity of the mass is the trigger mechanism of Stars. Yes that very gravity creates the density that builds the temperature to the point where your fission / fusion thingie happens... :) No mass sufficient, no bang.

Yes, mass first, to get the pressure up, and temperature second, so the reaction will actually go, and I can't think of any way to get the center of that much mass cold, so the point is probably moot. But you do have to have both confinement (pressure) and very high temperature.

Ah, I think there's an article on inertial confinement somewhere, I'll edit it in here. It's an interesting story.

And the reactions are nuclear.

Regards, John M.

mugaliens
2008-Nov-10, 09:21 PM
John Mendenhall and Mugaliens
Senior Members... I except that with your knowledge of the subject you might be able to actually detect this little bang in the sun... for goodness sake look at what I said. look at the OP. Like farting at thunder... there are you happy now ?:(

Awww... What's Mr. Grumpy-wumpy sad about? Did Mr. Grumpy-wumpy catch a wiff of ozone and methane during his last thunderstorm?

Seriously, astromark, I get your drift, and while it's indeed a bit like farting at thunder, while doable, it's also one of those relatively pointless "so what?" exercises.

astromark
2008-Nov-11, 08:51 AM
I am not the one that said any thing different here. I agree with...

"Seriously, astromark, I get your drift, and while it's indeed a bit like farting at thunder, while doable, it's also one of those relatively pointless "so what?" exercises." quote mugaliens

and well, yes sort of... 'grumpy' and sun scorched. Here in New Zealand we are under a fairly large hole in Earths Ozone cover most of the year. And guess who stood about the BBQ for to long. I am not a methane producer...:)lol.
Despite the ability of some science boof head to measure the odd signature of multi nuclear detonations against the back drop of the massive nuclear activity ongoing...I am still tempted to say to the question asked. NO ! we would not see any changes.

Vallkynn
2008-Nov-11, 09:30 AM
But what's the purpose of dropping a nuclear bomb into the sun? A drop of water into the ocean......

astromark
2008-Nov-11, 10:09 AM
I registered here just to ask this question so hopefully someone knows.

So, the sun is a fusion reaction and nuclear bombs are fission reactions. What happens if you explode a nuclear bomb inside a fusion reaction or a fusion bomb inside a fission reaction? Anything spectacular or just more of the same with a little extra on the side?

and I thought I was confused.
. . . . . on a good day. You would just spread out your nuclear contaminates further and quicker.

John Mendenhall
2008-Nov-12, 05:15 PM
and I thought I was confused.
. . . . . on a good day. You would just spread out your nuclear contaminates further and quicker.

True. One point that is seldom mentioned about fusion reactors is the internal radiation problem. Even if you can sustain and contain the fusion reaction, the radiation inside the vessel is busily changing the material of the containment vessel into something else, and thus destroying its strength and producing plenty of really nasty radioactive waste.

Witness the local fusion reactor, which toasted you with mere ultraviolet from 90 million miles away.

Regards, John M.