Clean Fusion Bombs: Possibility of "Clean" Explosions

[SkepticJ]

Could it be possible to one day create fusion bombs that are "clean"(not create radioactive isotopes and other nasty stuff that lingers for years)? The only thing it'd do is create thermal energy and the bast when it goes off?

 

[mathman]

To trigger a fusion bomb you need intense pressure and high temperature. At present using a fission bomb is the only practical method. Maybe in the distant future a laser trigger might be possible. At the moment they are simply trying to get something for a fusion reactor, using lasers.

 

[Morbius]

To trigger a fusion bomb you need intense pressure and high temperature. At present using a fission bomb is the only practical method. Maybe in the distant future a laser trigger might be possible. At the moment they are simply trying to get something for a fusion reactor, using lasers.

mathman,

That's correct.

Additionally, saying that the fusion reaction is "clean" because it doesn't
create any radioactive species [ at least not directly ] is short-sighted.

The main fusion reaction under consideration is "D-T" fusion:

D + T --> He4 + n + 17.6 MeV

The product isotope He4 is stable - so it is often said that fusion is
"clean" and doesn't produce radioactive species.

However, that neutron; the "n" ; receives 14.1 MeV worth of energy and
the next atom it hits will most likely become radioactive.

So D-T fusion is only "clean" if you look at just the first generation of
products. If you look one generation removed from the initial products -
then you are going to have radioactive species and fusion is not "clean".

In fact, fission gives you about 2 radioactive atoms per reaction, which
releases about 200 MeV worth of energy. Fusion gives you 1 radioactive
atom per reaction that releases 17.6 MeV of energy.

So in effect, on a per energy released basis; fusion is more than 5 times
more "dirty" than fission.

Dr. Gregory Greenman
Physicist

 

[hitssquad]

Clean fusion bombs via tungsten or lead jacketing

in effect, on a per energy released basis; fusion is more than 5 times more "dirty" than fission.

But can't the neutrons be stopped with lead?
http://www.cartage.org.lb/en/themes/Sciences/Chemistry/NuclearChemistry/NuclearWeapons/FirstChainReaction/TypesofNuclear/CombinedFission.htm

--
By jacketing the third stage with non-fissionable material, three stage devices can produce high yield clean weapons. Both Zuni and Tsar Bomba were in fact very clean devices - Zuni was 85% fusion and Tsar Bomba was 97% fusion. Both designs permitted replacing the lead or tungsten third stage jacket with U-238 however.
--

 

[Morbius]

But can't the neutrons be stopped with lead?

Yes - but you get radioactive lead - albeit a relatively short lived isotope.

http://www.cartage.org.lb/en/themes/Sciences/Chemistry/NuclearChemistry/NuclearWeapons/FirstChainReaction/TypesofNuclear/CombinedFission.htm

--
By jacketing the third stage with non-fissionable material, three stage devices can produce high yield clean weapons. Both Zuni and Tsar Bomba were in fact very clean devices - Zuni was 85% fusion and Tsar Bomba was 97% fusion. Both designs permitted replacing the lead or tungsten third stage jacket with U-238 however.
--

The "clean" Tsar bomb had a yield of 58 Megatonnes, or 58,000 kilotons.
If it was 97% fusion, then it was 3% fission. Thus the fission yield was
1740 kilotons - so Tsar was 116 times as "dirty" as Little Boy.

The last line above tells the story on this. The lead jacket is used in lieu
of a jacket of U-238. Under the flood of fast neutrons, the U-238 would
fission thus creating lots of radioactive fission products.

The fully configured Tsar bomb, with the U-238 jacket, was supposed to
have a yield of 100 Megatonnes. Since the fusion yield was 97% of the
tested 58 MT yield; or 56.26 MT - the fully configured device would have
a fission yield of 43.74 MT. So the never tested "full-up" version would be
56.25% fusion and 43.74 % fission. The "as tested" device, although having
a yield that was 97% fusion - there was still very substantial fission yield.

So the lead jacket case is only relatively clean in that you are not
letting the neutrons cause extra fissions. You aren't escaping the
fact that the neutrons are going to induce radioactivity; no matter
what you do.

Dr. Gregory Greenman
Physicist

 

[kapton]

wow!

Are you blind,

the energy that is emmited from Deutrerium and Tritium fusion on the order of 17.6 meV is radioative - a stream of photons of a 10^-14 gamma wavelength.

 

[SkepticJ]

Well if fusion won't work what about anti-matter-matter bombs? IIRC anti-matter reactions only give off gamma and thermal energy. How would one shield the gamma from getting out but still have the huge explosion?

 

[mathman]

There are at least two obvious problems using anti-matter (in spite of Star Trek). First, how to make it in sufficient quantities for a bomb? Second, what sort of container can you use to hold it until you want the bomb to go off?

 

[sid_galt]

There are at least two obvious problems using anti-matter (in spite of Star Trek). First, how to make it in sufficient quantities for a bomb? Second, what sort of container can you use to hold it until you want the bomb to go off?

Third, If accidentally the container gets broken or the bomb is hit with a nuclear missile, the whole bomb explodes. You don't want a 100,000 kiloton explosion in your own country.

 

[Pengwuino]

lol i think this proves how people actually do care about the environment. We want the weapons that are made to kill hundreds of millions of people to be as harmless to the environment as possible lol.

 

[Pyrovus]

Well if fusion won't work what about anti-matter-matter bombs? IIRC anti-matter reactions only give off gamma and thermal energy.

The only problem there is that the gamma rays produced are extremely high energy. As soon as they hit a nucleus, these rays would easily be able to knock several nucleons out, possibly even splitting the atom altogether. And these nucleons would likely have high kinetic energies, and thus be capable of causing further radioactivity upon impact with other nuclei.

 

[Astronuc]

Well if fusion won't work what about anti-matter-matter bombs? IIRC anti-matter reactions only give off gamma and thermal energy. How would one shield the gamma from getting out but still have the huge explosion?

Thermal energy implies particles other than photons, i.e. thermal energy is the manifestation of particle kinetic energy. A proton-anti-proton reaction generally causes pions or Kaons, which then decay muons and pions/muons respectively (see table on decay modes), and muons ultimately decay into electrons and neutrinos.

Photo-nucleon reactions have a threshold, the binding energy of the nucleons. The gamma-rays are much more likely to scatter off-electrons.

One does not keep gamma-rays from getting out - they scatter and each subequent photon has less energy.

 

[theCandyman]

Going back to the inital topic for a second, why make something like fusion a weapon!? I want to go into research on fusion when I graduate and I do not want to make it into something that is a weapon. I know that is far too idealistic, but I would feel better thinking that I am helping the world, not working towards its destruction.

 

[Morbius]

Going back to the inital topic for a second, why make something like fusion a weapon!? I want to go into research on fusion when I graduate and I do not want to make it into something that is a weapon. I know that is far too idealistic, but I would feel better thinking that I am helping the world, not working towards its destruction.

Candyman,

Although it is counterintuitive; nuclear weapons, in the opinion of many,
are responsible for keeping the peace.

There is an old expression from "Epitoma Rei Militaris" by Vegetius -
"Igitur qui desiderat pacem, praeparet bellum." or "If you want peace,
prepare for war".

Owing principally to both World War I and World War II; during the
first half of the 20th century - about 1 million people per year were
killed in war.

After 1945, that number dropped precipitously. What happened in
1945 to cause that? The dropping of the bombs on Hiroshima and
Nagasaki is what!

Due to the existence of nuclear weapons - all out war, like humankind
experienced twice in the first half of the 20th century, is no longer an
option.

The deterence to war afforded by the existence of nuclear weapons
has arguably saved many, many lives. In that matter; those that
work on nuclear weapons are helping to save the world - not destroy it.

Dr. Gregory Greenman
Physicist

 

[arivero]

The deterence to war afforded by the existence of nuclear weapons
has arguably saved many, many lives. In that matter; those that
work on nuclear weapons are helping to save the world - not destroy it.

Ir is regrettable that this people lost time "saving the world" instead of, for instance, decoding the origin of the spin-orbit coupling at magic numbers.

 

[SkepticJ]

lol i think this proves how people actually do care about the environment. We want the weapons that are made to kill hundreds of millions of people to be as harmless to the environment as possible lol.

Were did I say weapon? I didn't. The point of having non radioactive isotope creating bombs is you could use them for stuff without hurting biology for decades afterwards. Using nukes for blasting out huge amounts of rock in pit mines is one use I can think of, or that pesky mountain you want gone.

 

[SkepticJ]

There are at least two obvious problems using anti-matter (in spite of Star Trek). First, how to make it in sufficient quantities for a bomb? Second, what sort of container can you use to hold it until you want the bomb to go off?

Particle accelerators designed to make it in high amounts, they are powered by fusion power plants.

Magnetic bottles, like we already use to hold small amounts of anti-matter. Or the ones that keep plasma from touching matter in plasma rockets.<-- These things already exist; they just need improving before NASA uses them.
Or out in the realm of still speculation, thin tanks of monopolium .

 

[mathman]

Particle accelerators designed to make it in high amounts, they are powered by fusion power plants.

How high is high amounts - thousands of anti-protons? For bomb purposes, it may not be enough. There are no fusion power plants!

 

[Pengwuino]

Were did I say weapon? I didn't. The point of having non radioactive isotope creating bombs is you could use them for stuff without hurting biology for decades afterwards. Using nukes for blasting out huge amounts of rock in pit mines is one use I can think of, or that pesky mountain you want gone.

you guys get offended so easily lol. Its a weapon against mountains!

 

[Pengwuino]

Going back to the inital topic for a second, why make something like fusion a weapon!? I want to go into research on fusion when I graduate and I do not want to make it into something that is a weapon. I know that is far too idealistic, but I would feel better thinking that I am helping the world, not working towards its destruction.

... fusion bombs already exist. They are banned by international treaty though but Russia and the US most likely still have half a dozen or so sitting around. At least that's how i think it is... not sure. Can anyone clarify?

And whoever said the whole, nukes have stopped war... man... isn't that the greatest irony this worlds ever realized lol. The real question though is having the threat of a small accident causing the human race's exstinction vs the practical guarantee of no massive wars killing tens of millions ever happening again. And i hate when people think its bad to have nukes because there 'full of hate' or some other hippie slogan like that. I mean come on, look at Russia now and look at it the past 50 years. Take nukes outta the equation and we'd be doing WW5 right about now. We learned nothing from WW1 and WW2 (typical human nature) and would probably have gone into ww3 the second another nation got back to military strength. So yes, totally, peace = threat of annihilation!

 

[theCandyman]

I think the hydrogen bomb relies on fusion, I am not completely sure. I see the point of Morbius' comment, but I still see that a fusion bomb is a weapon and the point of a weapon is to kill.

 

[Pengwuino]

Yah... a hydrogen bomb can't be a fission bomb... that would make no sense

 

[Huckleberry]

I was under the impression the hydrogen bomb was a fission/fusion bomb. Please don't ask me to explain that. I was doing some research on fusion bombs and was looking at something called Red Mercury. Supposedly it is a pure fusion weapon, using deuterium and tritium to fuel the fusion reaction.

As far as nuclear weapons keeping the peace. Yeah, that may work for a time, but it seems inevitable that something that is built will eventually be used. I would rather see WW3-5 over the span of the last half a century or so than see the end of humanity in the next.

What was the question?
Huck

 

[Astronuc]

I was under the impression the hydrogen bomb was a fission/fusion bomb.

That was explained by Mathman and Morbius at the top of page 1 of this thread. The fission (Pu) trigger provides the high temperature required for the fusion reaction.

As for the US arsenal - The Trident II D5 missile can be fitted with the W88/Mk5 mini-thermonuclear warhead (~475 kT each (from FAS.org)). There are more than a few dozen.

 

[Morbius]

I was under the impression the hydrogen bomb was a fission/fusion bomb. Please don't ask me to explain that. I was doing some research on fusion bombs and was looking at something called Red Mercury. Supposedly it is a pure fusion weapon, using deuterium and tritium to fuel the fusion reaction.

Red Mercury is a bunch of nonsense.

Hydrogen bombs have to be triggered by atom bombs.

You have both fission and fusion going on in an H-bomb.

As far as nuclear weapons keeping the peace. Yeah, that may work for a time, but it seems inevitable that something that is built will eventually be used. I would rather see WW3-5 over the span of the last half a century or so than see the end of humanity in the next.

Why do you think a nuclear war is inevitable?

The history of the last half century is that war - both nuclear and
conventional is restrained. I wouldn't accept the millions of deaths
that WW3 - WW5 would represent so easily.

Nuclear weapopns represent such a large quantitative increase
in destructive power, that they are a qualitative difference - a difference
in kind. A typical 2000 lb. bomb as can be dropped from many of our
aircraft represents an ~ 1 tonne yield. A hydrogen bomb can be a
Megatonne - a million times greater. That's what I mean by a difference
in kind. I don't think you can extrapolate from past experience that since
every other weapon has been used that, of necessity, that means the
hydrogen bomb will eventually be used - not when it represents a jump
of 1 Million. Past experience with lesser weapons doesn't speak to the
use of thermonuclear weapons.

In our quest to avoid some imaginary nuclear war, we would be unwise
to eliminate nuclear weapons and once again make the world safe for
all out conventional war.

Dr. Gregory Greenman
Physicist

 

[Huckleberry]

In our quest to avoid some imaginary nuclear war, we would be unwise
to eliminate nuclear weapons and once again make the world safe for
all out conventional war.

Have you ever played poker? In order to keep peace through the use of nuclear weapons there must be the threat that they will actually be used. If nobody believes that they will be used then they lose their effectiveness in forcing nations to be peaceful. Eventually someone will call the bluff intentionally because they have nothing to lose and the potential for much to gain afterwards. The person with the fewest chips is most likely to make that call.

What was the question?
Huck

 

[NEOclassic]

Recalling Candyman's 1st post in this String:

Going back to the inital topic for a second, why make something like fusion a weapon!? I want to go into research on fusion when I graduate and I do not want to make it into something that is a weapon. I know that is far too idealistic, but I would feel better thinking that I am helping the world, not working towards its destruction.

Hi Candyman,
I seriously applaud your didication to the development of a sustained fusion reactor which will be more an engineering feat than a physics one. Be not deceived by the current fusion technology where tritium, as now used in relatively small applications, has become a sort of a poster-boy that could be reckoned as a kind of catalyst to fusion reactor success. And well it might be at the beginning of such a project, but its availability on a one to one demand basis could become an onerous problem for anyone of a few reasons, it would be wise to go for DD fusion rather than DT fusion. Recall what Morbius has mentioned often is that the neutron energy from the DT fusion is about 14 MeV compared to that of the DD fusion of about 2.5 MeV. Before making a point on the relative size of the reactor let's consider a modelling as follows: Centered in a large extremely heavy walled spherical shell is a smaller spherical shell made of some hydrogen sieve material, such as palladium, that contains the reaction zone where the neutrons that carry off so much of the fusion energy are created. These neutrons radiate isotropically and lose energy to the deuterated fuel that fills the gap between the two shells.
[The deuterated fuel could be water or lithium-D or dodecaborane etc because it is these light materials that most effectively absorb the kinetic energy transfers and so it becomes important that the thickness of the fuelgap be large enough that most of the neutron energy is retained. One reason why I would chose to go with DD is that the outer shell would be much smaller with DD than with the 14 MeV neutrons of the DT.]
Now then the absorbed energy of the fuel results in a temperature gradient of some sort but it should be possible to have, in onion layered fashion, bimetalic thermocouple porous shells whose voltages are to be amplified such that at say 200 KeV directed from the inner surface of the palladium shell to the dead centered pod/anvil that holds deuterons that have been shared from the Pd source can produce a continuum of sustained reaction. Don't you think? Its just a thought from one dedicated contrarian. Cheers, Jim

 

[Morbius]

In our quest to avoid some imaginary nuclear war, we would be unwise
to eliminate nuclear weapons and once again make the world safe for
all out conventional war.

Have you ever played poker? In order to keep peace through the use of nuclear weapons there must be the threat that they will actually be used. If nobody believes that they will be used then they lose their effectiveness in forcing nations to be peaceful. Eventually someone will call the bluff intentionally because they have nothing to lose and the potential for much to gain afterwards.

Huck,

Why do you think nobody believes they will be used?

The USA has its weapons laboratories maintaining these weapons so that
they will be ready to use. The U.S. Navy, for example, has its Trident
submarines practice launching nuclear missiles as part of their normal
operations.

It is quite clear that the USA will use nuclear weapons in response to a
nuclear attack.

You've bought into the questionable assumption proferred by many
anti-nukes that nuclear weapons are just too powerful to be used - so
they won't be used. They are wrong.

As an analogy, suppose a police officer mistook you for a dangerous
criminal and held you at gunpoint; ordered you to lie on the ground,
and not to approach him. Would you say, "Oh he's not going to shoot me;
he'd kill me - and that would be too strong a reaction. So the police
officer is just bluffing - and I can approach him"?

If you do approach inspite of the officer's admonitions not to - and the
officer feels threatened by the approach of someone he thinks [ albeit
mistakenly ] a dangerous criminal - he'll shoot and be well within his
rights to do so.

It would be STUPID for anyone to think that a large-scale attack on the
USA would not be met with a nuclear reprisal.

Look at President John Kennedy's handling of the Cuban Missile Crisis.
He put our nuclear forces on alert - and the USA was ready to release
a nuclear barrage against the Soviet Union. Kruschev was not dumb -
and did not assume that those missiles would not be fired.

Or look at the first Gulf War in 1991. Back then we knew [ as was later
confirmed by the post-war inspectors ] that Saddam Hussein actually
had chemical weapons at his disposal. His forces could very well have
used chemical weapons against coalition forces or Israel.

Yet the Iraqi military didn't use the one type of weapon that would
really have caused us some difficulty. Why not?

Because British Prime Minister Maggie Thatcher and then President
George H.W. Bush made it very clear to Saddam that use of chemical
weapons would meet a retaliation by tactical nuclear weapons.

To back that up, tactical nuclear weapons, AFAPs [ Artillery Fired
Atomic Projectiles ] were moved into the Iraqi theater, ready for use -
and they would have been used under the right circumstances.

NO - don't buy this propanganda that nuclear weapons can't be used.
The USA used them to end World War II, and will use them again if the
circumstances demand it.

Just as that police officer is ready, willing, and able to shoot you dead
if you don't comply properly - the USA will use its nuclear forces should
the need ever arise.

And that, my friend, is what keeps the peace.

Dr. Gregory Greenman
Physicist

 

[Morbius]

Hi Candyman,
I seriously applaud your didication to the development of a sustained fusion reactor which will be more an engineering feat than a physics one. Be not deceived by the current fusion technology where tritium, as now used in relatively small applications, has become a sort of a poster-boy that could be reckoned as a kind of catalyst to fusion reactor success. And well it might be at the beginning of such a project, but its availability on a one to one demand basis could become an onerous problem for anyone of a few reasons, it would be wise to go for DD fusion rather than DT fusion. Recall what Morbius has mentioned often is that the neutron energy from the DT fusion is about 14 MeV compared to that of the DD fusion of about 2.5 MeV.

NEOClassic,

Given that the energy loss is logarithmic - the difference between a
2.5 MeV neutron and a 14.1 MeV neutron is absolutely TRIVIAL.

Let's express the neutron energy, as is commonly done when we are
doing neutron slowing down calculations, in terms of its "lethargy".
The lethargy is the common logarithm of the ratio of the neutron
thermal energy divided by the energy of the neutron.

With E_thermal = 0.025 eV; the lethargy difference of a 2.5 MeV neutron
is 8.0; while the difference in lethargy of the 14.1 MeV neutron is 8.75 -
a rather trivial difference. In fact, the fact that you have hydrogen
around - means that you need only about ~2 more collisions to slow down
the 14.1 MeV neutron on average, than you need for the 2.5 MeV neutron.

So the claimed advantage of D-D fusion over D-T fusion due to the
lower product neutron energy is INSIGNIFICANT.

However, it is more difficult to achieve the D-D fusion conditions than
it is for the D-T fusion conditions. Therefore, by going to D-D fusion,
you increased the difficulty of achieving fusion - and the payback of
lower product neutron energy is TRIVIAL. So it makes for a very bad
tradeoff.

The scientists working on fusion aren't dumb - they've chosen to work on
D-T fusion for a reason.

Before making a point on the relative size of the reactor let's consider a modelling as follows: Centered in a large extremely heavy walled spherical shell is a smaller spherical shell made of some hydrogen sieve material, such as palladium, that contains the reaction zone where the neutrons that carry off so much of the fusion energy are created. These neutrons radiate isotropically and lose energy to the deuterated fuel that fills the gap between the two shells.

Just how big is your fusion reaction zone going to be? The mean free
path of high energy neutrons - be they 2.5 MeV or 14.1 MeV is measured
in 10s of centimeters. You are not going to be able to get much energy
transfer from the neutrons in order to sustain your fusion reactions.
Not unless your reaction zone is orders of magnitude greater in size
than anything that anybody is considering.

No - you sustain the fusion reaction itself by capturing the energy of
the other reaction product - the charged ion. The neutrons are captured
in a "blanket" outside the reaction zone. That's where they can be used
to breed additional Tritium [ by including Lithium-6 in the blanket
material ], as well as where you recover the bulk of the energy desired
for the power plant.

[The deuterated fuel could be water or lithium-D or dodecaborane etc because it is these light materials that most effectively absorb the kinetic energy transfers and so it becomes important that the thickness of the fuelgap be large enough that most of the neutron energy is retained. One reason why I would chose to go with DD is that the outer shell would be much smaller with DD than with the 14 MeV neutrons of the DT.

As above - the difference in shell thickness would be TRIVIAL.

Now then the absorbed energy of the fuel results in a temperature gradient of some sort but it should be possible to have, in onion layered fashion, bimetalic thermocouple porous shells whose voltages are to be amplified such that at say 200 KeV directed from the inner surface of the palladium shell to the dead centered pod/anvil that holds deuterons that have been shared from the Pd source can produce a continuum of sustained reaction. Don't you think?

My thoughts - not much.

Dr. Gregory Greenman
Physicist

 

[Huckleberry]

Morbius,

I personally do believe the threat of nuclear war is real and that they will some day be used. It seems you're attempting to confuse me with some weird logic.

Why do you think a nuclear war is inevitable?

Why do you think nobody believes they will be used?

It would be STUPID for anyone to think that a large-scale attack on the
USA would not be met with a nuclear reprisal.

This is essentially why I believe keeping peace with nuclear weapons will make nuclear war inevitable eventually. How many nations are there in the world that would like to see the downfall of the U.S.? How many terrorist organizations would be willing to use a nuclear weapon against the U.S.? Should we invade every third world nation on the planet that could potentially harbor resentment towards the U.S. looking for terrorists real or imaginary? Wouldn't that just accelerate other nations resentment against us and cause them to come together while we are separated from our allies?

Admittedly, there are a lot of what ifs, but this does seem to be a very plausible, natural progression to me. I have very little doubt that nuclear weapons will be used. I am not saying total human annihilation, just that they will eventually be used and that the more we rely on them for peace the sooner it will happen.

In your cop scenario only one person has a gun. Also, I'm not sure I like the inclusion of myself in your scenario.(please let me be my own puppet) Imagine if they both believed they had the proper authority (were both good guys from their own points of view) and they both had guns pointed at each other and came to an unresolvable conflict of interests. How would that scenario go then? All we need is the unresolvable conflict of interests such as freedom of government or availability of resources and then there will be people anxious to take advantage of the chaos that would result.

The reaction of the U.S. and the world to the 9/11 attack solidifies my opinion on the matter. That was the loss of a few major buildings and a few thousand lives. Law has changed arguably at the expense of freedom and constitutional rights, wars have been fought under apparently false pretenses, foreign relations strained somewhat, and a general increase in discontent in Arab nations. This is all bad for the U.S. and good for its enemies, but what should we do, nothing? There will always be a reaction. The masses will demand it. Aggression begets aggression (not every day you get to use the word beget ) Peace begets peace (Wow! twice in one day )

What was the question?
Huck

 

[sid_galt]

However, it is more difficult to achieve the D-D fusion conditions than
it is for the D-T fusion conditions.

So why is it more difficult? Isn't the coulomb barrier the same?
Or is it because the nuclear force is greater in D-T that D-T scores over D-D?

 

[Astronuc]

Certainly, the DT reaction (17.6 MeV) is more exothermic than DD (~3.27 MeV for ³He + n products, or 4.03 MeV for T + H products).

Perhaps it is that D is more stable than T, and the compound nucleus is more likely to form (fuse) in the case of DT rather than scatter in DD.

 

[Morbius]

So why is it more difficult? Isn't the coulomb barrier the same?
Or is it because the nuclear force is greater in D-T that D-T scores over D-D?

Sid,

You got it - Coulomb barrier is the same, nuclear attraction greater.

Dr. Gregory Greenman
Physicist

 

[Morbius]

In your cop scenario only one person has a gun. Also, I'm not sure I like the inclusion of myself in your scenario.(please let me be my own puppet) Imagine if they both believed they had the proper authority (were both good guys from their own points of view) and they both had guns pointed at each other and came to an unresolvable conflict of interests. How would that scenario go then?

That was the Cold War - and nuclear weapons kept it a standoff until the
USSR couldn't maintain their threat - it became too expensive. The USA
had an advantage in technology - our bombs are smaller - so the missiles,
which are the expensive part, are WAY, WAY cheaper. In addition, the
USA has a bigger economic engine to fund this. So it cost the USA less
in actual cost - and way, way less in fractional cost [ % of GDP, for ex. ].
The USSR collapsed from the strain.

It didn't escalate into a hot war - because of the nuclear deterrent.

Aggression begets aggression (not every day you get to use the word beget ) Peace begets peace (Wow! twice in one day )

I don't believe the those "slogans". Weakness begets aggression -
strength begets peace is what history teaches.

Dr. Gregory Greenman
Physicist

 

[Morbius]

Morbius,

I personally do believe the threat of nuclear war is real and that they will some day be used. It seems you're attempting to confuse me with some weird logic.

Huck,

The logic isn't weird.

The fact that the USA is ready, willing, and able to use nuclear weapons,
makes the threat of their use believable; thus giving rise to deterrence.

It is that deterrence that prevents war.

Nations don't go to war by happenstance - they CHOSE to go to war.
When the status quo of some "unresolvable" conflict becomes more
burdensome than the consequences of war - you get war.

Nuclear weapons "raise the bar" with respect to the consequences of war.

Imagine that you are the absolute ruler of a nation. What is so important
to you that you will risk conflict with a nuclear armed superpower?

What are you willing to go to war for - when the downside is the nuclear
devastation of your nation?

Dr. Gregory Greenman
Physicist

 

[SkepticJ]

How high is high amounts - thousands of anti-protons? For bomb purposes, it may not be enough. There are no fusion power plants!

You are correct there are none, now. If you read any number of my threads you'll see I ask questions about future possibilities a lot. Doesn't matter to me if it won't be possible for decades, or even centuries.

 

[russ_watters]

Small expansion because I don't want this to become too political...

The logic isn't weird.

The logic of MAD seems weird at first, but really its just a standard risk-reward analysis. Nuclear weapons make the risk so high that no reward is worth the risk of using them.

What makes the current situation different is that framing the problem in risk-reward terms requires the involved parties to be rational. The enemies that we are worried about today (terrorists and rogue nations) are not necessarily rational.

Have you ever played poker? In order to keep peace through the use of nuclear weapons there must be the threat that they will actually be used. If nobody believes that they will be used then they lose their effectiveness in forcing nations to be peaceful. Eventually someone will call the bluff intentionally because they have nothing to lose and the potential for much to gain afterwards. The person with the fewest chips is most likely to make that call.

The poker analogy is a good one, but you get it wrong at the end: there is never a point at which you have so few chips that you're willing to throw them away on a virtual guaranteed losing hand. And that's what MAD is.

You are correct there are none, now. If you read any number of my threads you'll see I ask questions about future possibilities a lot. Doesn't matter to me if it won't be possible for decades, or even centuries.

The reason scientists and engineers don't generally look that far into the future is that for the purposes of science and engineering, a 30 year time horizon and "never" are essentially the same thing.

 

[Huckleberry]

Have you ever played poker? In order to keep peace through the use of nuclear weapons there must be the threat that they will actually be used. If nobody believes that they will be used then they lose their effectiveness in forcing nations to be peaceful. Eventually someone will call the bluff intentionally because they have nothing to lose and the potential for much to gain afterwards. The person with the fewest chips is most likely to make that call.

The poker analogy is a good one, but you get it wrong at the end: there is never a point at which you have so few chips that you're willing to throw them away on a virtual guaranteed losing hand. And that's what MAD is.

The person with fewer chips in a poker game is in a weaker position. A loss of fewer chips is a more signifigant loss to that player. If one player has a vastly superior number of chips they can force the other out of the game entirely buy going all in. So in the example the person with the fewest chips either forfeits or calls the bluff. It is a rational decision to call the bluff.
Even if it wasn't rational people spend millions of dollars every day in casinos and lotteries when the games are designed to earn more money than they pay. It is not a rational decision to gamble and yet people do it, albeit for entertainment and not under the threat of nuclear death. It's not a perfect scenario.
There are circumstances where nations or terrorist organizations would initiate a nuclear exchange. My point for the scenario is if a nation, or a secular leader of a nation or organization, that has nuclear capability is desperate and their options are limited to give up autonomy or die, then they are actually very likely to try to hurt their opponent as best they can before they are forced out. What would have happened if Stalin or Hitler had nuclear weapons during the Cold War period? Or if Saddam Hussein had nuclear weapons how that would affect the politics of the Middle East and our involvement in the war in Iraq. How long will it be before a terrorist organization obtains a nuclear weapon? Is it feasible that we can keep them out of their hands forever? The power vacuum created by the chaos could be beneficial to them.

I apologize for my comments in this forum. Been here a few days and I'm still learning the ropes. I realize now the subject matter of my posts here do not belong in this thread. Again, I apologize.

Huck

 

[Morbius]

There are circumstances where nations or terrorist organizations would initiate a nuclear exchange. My point for the scenario is if a nation, or a secular leader of a nation or organization, that has nuclear capability is desperate and their options are limited to give up autonomy or die, then they are actually very likely to try to hurt their opponent as best they can before they are forced out. What would have happened if Stalin or Hitler had nuclear weapons during the Cold War period?

Huck,

Good Grief - go study some history!

Stalin DID have nuclear weapons during the Cold War! The U.S.S.R.
exploded their first nuclear weapon in 1949. Stalin was still the
leader of the Soviet Union when they developed nuclear weapons.

Even someone like Stalin - who was bent on the expansion of the Soviet
empire did not attack the USA; even when he had nuclear weapons. The
reason not is that the USA had a superior nuclear force. That deterred
any attack by Stalin.

Or if Saddam Hussein had nuclear weapons how that would affect the politics of the Middle East and our involvement in the war in Iraq.

Saddam Hussein came very close to having nuclear weapons - which is
why the USA put a stop to his ambitions. In January 2004, the chief
nuclear weapons inspector, Dr. David Kay had this exchange with
Senator Cornyn while Dr. Kay was testifying before the Senate Armed
Services Committee:

http://www.globalresearch.ca/articles/KAY401A.html

"CORNYN: You said something during your opening statement that
intrigues me, and something that I'm afraid may be overlooked in all of
this back and forth; and that has to do with proliferation...

But do you consider that to have been a real risk in terms of Saddam's
activities and these programs -- the risk of proliferation?

KAY: Actually, I consider it a bigger risk. And that's why I paused on the
preceding questions. I consider that a bigger risk than the restart of his
programs being successful.

KAY: I think the way the society was going, and the number of willing
buyers in the market, that that probably was a risk that if we did avoid,
we barely avoided."

Dr. Kay stated that we "barely avoided" having a nuclear armed Iraq.
That is why it is important to shutdown the nuclear programs of rogue
nations so that they can't become a nuclear threat; and why, as former
President Clinton stated in his proclamation of August 11, 1995:

http://www.lcnp.org/disarmament/npt/polsta4.htm
http://www.inesap.org/bulletin22/bul22art06.htm

"As part of our national security strategy, the Unitied States must and
will retain strategic nuclear forces sufficient to deter any future
foreign leadership with access to strategic nuclear forces from acting
against our vital interests and to convice it that seeking a nuclear
advantage would be futile. In this regard, I consider the maintenance of
a safe and reliable nuclear stockpile to be a supreme national interest
of the United States."
-President Bill Clinton, August 11, 1995

it is important that the USA retain its nuclear weapons.

In November 1997, President Clinton signed Presidential Decision
Directive 60. Before that date, it was the policy of the USA to someday
get rid of its nuclear weapons. President Clinton changed that policy
to one where the USA would rely on nuclear weapons for its protection
for the "INDEFINITE FUTURE". See:

http://www.lcnp.org/disarmament/npt/polsta4.htm

How long will it be before a terrorist organization obtains a nuclear weapon? Is it feasible that we can keep them out of their hands forever?

The production of nuclear weapons is a very large scale process that is
beyond what a terrorist organization could muster. Only a nation will
have the resources to produce these weapons. The only way a terrorist
organization can get their hands on a nuclear weapon is if it is provided
by a nation that supports terrorism. That is why it is imperitive to
deny nuclear weapons to such nations. [ like Iraq, Iran, Libya...]

However, as Russ correctly points out - we are straying from science
and into politics.

Dr. Gregory Greenman
Physicist

 

[russ_watters]

The person with fewer chips in a poker game is in a weaker position. A loss of fewer chips is a more signifigant loss to that player. If one player has a vastly superior number of chips they can force the other out of the game entirely buy going all in. So in the example the person with the fewest chips either forfeits or calls the bluff. It is a rational decision to call the bluff.

Have you played poker? I don't care if you have $5 in the pot and $5 in your stack, you don't bet that $5 in your stack on a guaranteed loser (say, a 2-7). Its throwing your money away.

And this isn't the way you apply the analogy anyway: Remember, in the nuclear deterrence game, no one has any chips in the pot yet. Everyone has their cards and their stack, but hasn't risked anything yet and has nothing to gain yet. If you haven't put any chips into the pot yet and you're guaranteed to lose if you do, you don't bet. Simple as that.

Even if it wasn't rational people spend millions of dollars every day in casinos and lotteries when the games are designed to earn more money than they pay. It is not a rational decision to gamble and yet people do it, albeit for entertainment and not under the threat of nuclear death. It's not a perfect scenario.

In poker, the house isn't playing: you're playing against other people.

Morbius handled the rest just fine - it seems your biggest misunderstanding here is the history of the situation (which could be why you're applying the poker analogy wrong): Hitler wasn't alive during the Cold War and Stalin did have nuclear weapons.

 

[sid_galt]

Thank you for the replies Dr. Greenman and Dr. Astronuc.

the compound nucleus is more likely to form (fuse) in the case of DT rather than scatter in DD.

What is DD scattering? Does it mean that the DD nuclei simply bounce of each other instead of fusing?
If that is so, what are its causes?


Additionally, I read in a physics text that in the sun, most of the protons simply bounce of each other instead of fusing. Is this true and if it is, then is it because of excess kinetic energy of the particles so that the nuclear force can't hold them together after collision?


Is there an optimum KE at which DT fusion occurs?

 

[Morbius]

Thank you for the replies Dr. Greenman and Dr. Astronuc.

What is DD scattering? Does it mean that the DD nuclei simply bounce of each other instead of fusing?
If that is so, what are its causes?

Although it is only one component or cause of scattering - the simplest
to explain is "potential scatter".

You have to remember that in the nuclear regime, we're in the realm of
quantum mechanics [ also called "wave mechanics" ] where particles are
described by their wave functions.

The nuclear attractive force can be represented as a "potential well" -
a dip in the potential energy. [ A ball that has fallen down an old well,
of the familiar kind, is in a gravitational potential well. ]

The well has an edge. Any time there is a discontinuity in the space
through which a wave travels - you get reflections. When light goes
from air to glass - the light partially reflects from the surface of the
glass because the speed of light in the material changes [ they have
different index of refraction ].

So too in the nuclear realm - the boundary of the potential well is a
discontinuity as far as the wave function of the particles [ nuclei ] are
concerned - and the wave can reflect. That reflection is scatter -
in this case, it is called "potential scatter" since you are scattering off
the potential well boundary.

Dr. Gregory Greenman
Physicist

 

[Astronuc]

What is DD scattering? Does it mean that the DD nuclei simply bounce of each other instead of fusing?
If that is so, what are its causes?

In a confined plasma the ions (nuclei) and electrons are colliding. There are ion-ion interactions, electron-electron and ion-electrons. The electrons scatter off one another - energy is too low for any transformation, the electrons are trying to recombine with the ions to form atoms (lower energy state), and the ions scatter or collide and combine. Basically if two ions collide and but do not fuse, they then scatter as describe by Morbius. One can demonstrate experimentally, that DT is more likely than DD at a given energy, as Morbius has discussed elsewhere.

Additionally, I read in a physics text that in the sun, most of the protons simply bounce of each other instead of fusing. Is this true and if it is, then is it because of excess kinetic energy of the particles so that the nuclear force can't hold them together after collision?

Most likely someone has demonstrated that the cross-section (probability) for fusion of protons (p + p) is much lower than the cross-section for scattering, i.e. in an interaction between protons, there is a higher probability of scattering than fusing. Obviously, the sun is there, so it works.

I don't know if it is excess kinetic energy necessarily that is limiting the fusion reaction rate, but beyond some energy, yes the excess kinetic energy would reduce the probability of fusion. I think however, it is simply that scattering is more likely than fusion.

Is there an optimum KE at which DT fusion occurs?

If you go to the thread on Nuclear fusion reactions, I provided a figure with reaction rate parameters for the various fusion reactions. The DT parameter peaks around 80 keV which would be the optimum temperature (kinetic energy) for a reaction. Actually it is pretty broad so between 50-80 keV would be good, but the lower the better since is means less energy input/recycled.

 

[Morbius]

In a confined plasma the ions (nuclei) and electrons are colliding. There are ion-ion interactions, electron-electron and ion-electrons. The electrons scatter off one another - energy is too low for any transformation, the electrons are trying to recombine with the ions to form atoms (lower energy state), and the ions scatter or collide and combine. Basically if two ions collide and but do not fuse, they then scatter as describe by Morbius. One can demonstrate experimentally, that DT is more likely than DD at a given energy, as Morbius has discussed elsewhere.

Exactly - when nuclear particles collide there are multiple possible
outcomes - "channels" as they are called. The probability of each of
these outcomes or channels is dictated by the laws of quantum
mechanics.

The collisions between nuclear particles are stochastic - that is you
don't know exactly what will happen - you only know what the various
probabilities are. Even Mother Nature doesn't know what is going to
happen - the "choice" is made at the time of the collision.

That's how quantum mechanics works. For example, let's take the
example of the Stern-Gerlach experiment. You send a stream of
electrons or other particles with spin = 1/2 through a magnetic field
with a gradient in the vertical direction. Particles with spin = 1/2
can have one of two states - spin up or spin down. In the magnetic
field gradient, the spin up particles are deflected upwards, the spin
down particles are deflected downward. However, a given electron
doesn't know if it is spin up or spin down until it is forced to make
the "choice" when going through the magnetic field.

In quantum mechanical terms, the particle can be thought to be
represented by both a spin up and a spin down wave function. When you
make a measurement - you "collapse the wave function" - you force the
particle to choose one path or the other.

Likewise, a given ion doesn't know whether it will fuse or scatter before
it encounters another ion. The ions "make the choice" at the instant of
collision - with the probabilities of each event dictated by quantum
mechanics.

In the nuclear realm, where quantum mechanics reigns; there are no
absolutes, only probabilities.

Dr. Gregory Greenman
Physicist

 

[sid_galt]

Thank you for the replies.

So what is the most important factor the probability of fusion depends on?
Temperature of the plasma?

 

[Morbius]

Thank you for the replies.

So what is the most important factor the probability of fusion depends on?
Temperature of the plasma?

Sid,

The reaction cross-sections [ probabilities ] are energy-dependent - they
depend on the energy of the ions that are colliding.

In a sense, that depends on the temperature - because the temperature
tells you the distribution of energies. For a given temperature, not all
ions will have the same energy - the temperature tells you what the
distribution of energies looks like.

For a given collision, the probability of fusion depends on the energies of
the colliding ions.

So you have, in effect, a two-level probability scheme. For a given
temperature T - that tells you the probability that a randomly chosen
ion will have energy E. Likewise, the temperature T tells you the
probability that another ion will have energy E' - which may or may
not equal E.

The energies of the two ions, E and E'; will give you the probability of
a reaction - be it a scatter, or fusion, or whatever.

To get the total probability, you have to integrate over all possible
combinations of E and E'.

In addition, you have to take into account the probability that the
ion with energy E will collide with a particle of energy E' - and that's
a function of the density.

So you have a very complex function of temperature and density.

Dr. Gregory Greenman
Physicist

 

[spartan3123]

i don't believe so. World war one was caused by colonialism, created by some of the powerful empires at that time - the British empire and Germany, Germany and England were competing for control of the seas, both side built their militaries so they could maintain defend their colonies in Africa and else where. Tensions soon built up cause many "Nations" to form alliances. Really no one was "good" in W1 (expt USA) even France had colonised some countries. After the assination of some guy in the Austro Hungry Empire War was declared and all the countries stayed true to their pacts.

It took 2 world wars for the world to realize that colonialism could not operate as the world is far 2 small ( Japs started as well)

USA also pressured England to release all of its former colonies and the UN was formed to ensure that all nations and cultures of all Tec level ( min: farming societies) would not be invaded.

Thus after W2 even if nucs wern't invented there their probably wouldn’t be any more wars at the worst there would be 3 ( cold war).

It is true that NUC have played a contribution to ‘world peace’ but I think it is the change in attitudes of people that has made to largest contribution.

 

[LennoxLewis]

Just as that police officer is ready, willing, and able to shoot you dead
if you don't comply properly - the USA will use its nuclear forces should
the need ever arise.

And that, my friend, is what keeps the peace.

Dr. Gregory Greenman
Physicist

I respect your knowledge of nuclear physics, but i don't believe what you're saying about nuclear weapons keeping peace for a moment.

In your police officer analogy, what if another man comes along with a gun? We already know what the answer is... it doesn't prevent peace.

Now to make things even worse... what if it's a man who thinks his life on Earth is nothing compared to the afterlife Allah will grant him, hence, he will not hesitate to do something that will result in the end of his own life on earth? What if a terrorist with no clear own bomb able country launches on at the US and unchains an string events that result in the end of 99% of human life and setting us back to the stone ages technology wise?

I recommend to watch the movie Threads (1984), which shows the horrible consequences of MAD. Better to do WWI & II over than setting us back thousands of years.

 

[Morbius]

I respect your knowledge of nuclear physics, but i don't believe what you're saying about nuclear weapons keeping peace for a moment.

In your police officer analogy, what if another man comes along with a gun? We already know what the answer is... it doesn't prevent peace.

LennoxLewis,

That's why I don't advocate letting another man have the gun. I don't want any more countries to
have nuclear weapons.

Now to make things even worse... what if it's a man who thinks his life on Earth is nothing compared to the afterlife Allah will grant him, hence, he will not hesitate to do something that will result in the end of his own life on earth? What if a terrorist with no clear own bomb able country launches on at the US and unchains an string events that result in the end of 99% of human life and setting us back to the stone ages technology wise?.

Again - I certainly do NOT want Iran or Libya or Syria or... to have nuclear weapons.

However, I cite Pulitzer Prize winning historian Richard Rhodes in the following:

http://www.spiegel.de/international/0,1518,367260,00.html

Dr. Gregory Greenman
Physicist

 

[LennoxLewis]

LennoxLewis,

That's why I don't advocate letting another man have the gun. I don't want any more countries to
have nuclear weapons.


Again - I certainly do NOT want Iran or Libya or Syria or... to have nuclear weapons.

However, I cite Pulitzer Prize winning historian Richard Rhodes in the following:

http://www.spiegel.de/international/0,1518,367260,00.html


Dr. Gregory Greenman
Physicist

Okay, you don't want other countries to have them, but let's look at the reality of the situation: there are nearly 10 countries/states that have them, and several others that share them. So your analogy is off and unrealistic.

As for your article, great, but what if someone with nothing to lose launches a nuclear weapon and basically ends mankind because of the retaliation?