Question about nuclear bombs

[Tinsel]

I understand that in a chemical reaction, when two or more element's protons and electrons form new bonds that are stable, that there is possibly a change in physical form and that heat is given off during the reaction. The heat given off during the reaction results in a loss of mass, so if you look at it that way, there is heat given off when mass is converted to energy. This is an underlying concept of nuclear reactions, isn't it. That there is a great amount of energy released when a substance is converted into energy. Well how can this be described more accurately. What is this splitting of the atom all about, and how is the nucleus involved here. What is going on exactly.

 

[Ursa major]

Chemical reactions can be exothermic (they release energy in the form of heat) or they can be endothermic (they require and so absorb energy).



As for nuclear reactions, check out these:

Nuclear fission - Wikipedia, the free encyclopedia

Nuclear fusion - Wikipedia, the free encyclopedia
​

 

[Tinsel]

So those are the proper terms for describing the process. I did not know about the later type of reaction.

Yes, read, read, and read...more. Where is the laymans description? I might have to read those articles, thanks.

 

[Doctor Crankenstein]

I'll give the layman's version a crack.

Fission - the nuclei of a large fissile substance (uranium for example) is bombarded by a neutron which causes it to split into two smaller substances. In the process it releases more neutrons to continue the process and large ammounts of energy.

Fusion - smaller atoms come together under extreem conditions (energy, density, heat) and bind together into larger atoms releasing energy in the process.

Nuclear weaponry is Fission. Hiroshima was Uranium. Nagasaki was Plutonium.

Suns are Fusion.

How's that?

 

[Tinsel]

I'll give the layman's version a crack
/*(see above)*/
How's that?

That is more towards what I wanted to hear, but I can't quite reply in such a way as to further the conversation just yet because my mind is off topic, but that information is something to work with. The basic presumption that I had was that matter is being converted into heat energy and you said that particles are used to split the nuclei of various types of atoms/elements.

 

[chrispenycate]

Forget the mass difference with chemical reactions; even if you could collect all the bits and pieces of your stick of dynamite back together, there is nothing sensitive enough to measure it. It'd be a bit like trying to detect the increase in mass of a car pulling away from traffic lights; the air compressed into its engine would have several orders of magnitude more effect.
A nucleus of helium is, however, a teetzy weeny bit less massive than two nuclei of deuterium, for the same two protons, two neutrons, and each heavier element continues the trend until iron, after which you're going back uphill – and by the time you get into the transuranics, this has become a serious factor. You can either consider this mass as the binding energy holding the nucleus together, (not particularly well, in the case of the transuranics) or a fundamental particle; when it is released, the cee squared factor means that very few picograms make lots and lots of ergs. Or joules, or BTU, not to mention a fair amount of destruction.

The instability of the very heavy elements is generally used to trigger this, particularly with Uranium 235 and plutonium 239's inability to hang onto their neutrons, but this doesn't have to be the case. Sufficiently high temperatures and pressures (as in the heart of a star) will do the job quite nicely. Unfortunately, (or perhaps not that unfortunate) the only places we can duplicate these conditions on Earth are very temporarily in particle accelerators like the one down the road in CERN, or in nuclear explosions.
Research continues, and it is not impossible that we will one day have a bomb the size of a matchbox for annihilating city blocks (although I'm more in favour of antimatter to that end) but, for the time being, if you want a nuclear weapon I'm afraid it will be at least suitcase size, with a kilogram of plutonium and twice that amount of chemical explosive to squeeze it together.

This wasn't very layman, was it?

 

[Tinsel]

Instead of a bomb, if they were able to harness the heat energy in the conversion of mass to energy of an atom or a whole element or an object, than that would solve all energy consumption needs around the world. I don't really hear anything about this effort or if it is even on the table. Instead you hear a lot about weapon making which was not meant to happen in the first place.

So if the nucleus is split, than this causes a total mass conversion into heat energy? Is there nothing left over?

 

[chrispenycate]

If the nucleus splits, or is persuaded to split, a tiny fraction of a percentage of the mass is released as energy. Most goes on as different elements or different elementary particles. Frequently neutrons. But total mass conversion, as with a matter/antimatter interaction, would produce a million times as much energy (figure pulled out of my hat; too lazy to actually calculate it)

Now, atoms are very small, and do not contain much mass, so one atom being converted to energy would not make much difference to the Earth's energy needs, and the energy comes out in the most disorganised fashion possible – heat (well, wide band electromagnetic radiation, generally, but that translates to heat by the time we're trying to use it), and that needs steam turbines or whatever to convert it to something useable. With a bomb, you don't worry about details like that; heat will do just fine.

Layman's terms. We are nowhere near total mass conversion yet. The principal problems with energy are not the quantity, but availability, transport and storage, none of which would be effected by greater generating potential. The only nuclear reactions we have so far succeeded in disciplining are heavy element fission, and when you break up the big atoms some of the small ones you get as waste are pretty nasty. Also, having lots of spare neutrons kicking around tends to modify the matter in the containment vessel.

Everybody and his uncle is cheering for fusion; sticking multiple light nuclei together to get fewer heavier ones. If they can make it work, it could well be the energy source of the future, but until there is a working prototype, it's difficult to guess what the side effects will be.

Since what we are describing here is basically a very small star, or a continuously exploding hydrogen bomb, NIMBY tactics might be wise; but then transporting the power where it's actually needed becomes an issue.

If solar cells were more efficient, we might be able to harness the flash directly, without needing to go through heat and turbines; but is solar cells could be made that efficient, we would probably have enough energy, anyway. And still the problem of getting it where it's needed (and storing it, yes.)

France, fifty years ago, tried to go all modern, and nuclear. It wasn't a disaster, but it wasn't an outstanding success, either.

And bombs are easy relative to controlled continuous power output; it's always easier to break something than to create.

 

[Tinsel]

What exactly does a nuclear power plant work on. Based on the information in your post it seems like they are able to generate power (as a byproduct?) but they are not able to convert atomic mass into pure energy. Are they making weapons down there or are they creating an energy supply, or is energy a byproduct as a result of some other purpose.

 

[chrispenycate]

Your standard fission power station uses enriched uranium (larger percentage than natural of U235, which is the less stable isotope (stop me when I'm not layman enough) When a nucleus of this is hit by a neutron (heavy nuclear particle with no charge) it has a tendency to break into pieces; and some of those pieces tend to be neutrons. When more neutrons are being released than are escaping, we have a chain reaction; we call the mass of metal sufficient for this critical mass.
When the big atom breaks down into several smaller ones there is a miniscule loss of mass, which turns up as quite a large quantity of energy (megawatts for picograms), and the thing heats up. There are a number of ways to use this heat to produce electrical energy, often involving heat exchangers and liquid sodium and other such esoteric techniques, but the simplest is to consider it as a fire, get it to turn water into steam, and use that to run an ordinary, primitive steam turbine with bearings and bits that wear out, just like a coal fired generator.

A breeder reactor turns some of the poor uranium (almost entirely U238, the most stable, long lived isotope) into Plutonium 239, an even more effective fuel, and the heart of modern atomic bombs. Separating this out from the other radioactive waste products in the spent fuel rods is dangerous, unpleasant and very profitable, because this is the only way this substance can be obtained. It doesn't exist in nature, so is extremely poisonous, as well as being radioactive. I still think the energy is their primary aim; the nuclear weapons are just perks.

But nobody trust Iran when they say they're only in it for the power…

So, a miniscule percentage of the incoming mass ends up as energy, most of it goes out as unchanged, and is recovered from the waste, and some – quite a bit – ends up as different elements, many radioactive in their own right, which are a nuisance to get rid of (especially as you don't want a terrorist either getting his hands on them, or spreading them over the countryside).

 

[Tinsel]

That was a good post Chrispenycake. That was nice and clear. I was wondering about the whole nuclear question and I'm sure that it would take a lot of reading to uncover these answers. I just wanted to have some ground in the matter as I have been reading a little bit about Einstein's theory of relativity or modern physics.

Now the radio active byproduct of the synthesis is a potential weapon. We have now learned about this here, not that I was looking for that information, but I should say something about this new fact that has been introduced.

Well I know what it feels like to be poisoned and I'm tired of it. When you work in an industrial area and use equipment there are safety concerns, yet I have seen a number of technological improvements. Now this potential risk is very severe, and you have to wonder if this has lead to certain actions being taken. Such information could reduce the confusion over what position to take on Iran or Korea. It may reduce the concern over other problems that are not as critical in nature.

 

[chrispenycate]

Studying the development of human technology it's clear that just about any new procedure/technique/invention can be used as a weapon. If there's one thing we're good at, it's beating ploughshares into swords (or just hitting our enemies with the plough).

If you want poison, you've got a good one at the enrichment stage; fluorine. This might by now have changed, but at the beginning of separation, the only uranium compound that could be gasified (evaporated?) was uranium hexafluoride; as the lighter isotope would diffuse faster than the more stable heavier one, it could be partially separated, or at least concentrated, by successive passes.

Now fluorine is seriously nasty, and chews through just about anything (Teflon, Polytetrafluoroethylene or PTFE because nobody could spell it, was invented at this time to have something to put it in) and the only other place it turns up in quantity (apart from toothpaste) is in aluminium smelting; and there it's supposed to stay as compounds, not go out on its own.

Unfortunately, since it's used at the start of the process and would be the same for civilian or military uses, you can't judge the final use from increase in fluorine poisoning.

 

[Tinsel]

Just one post review comment.

This whole concept of converting mass to energy isn't very precise in fact. If only a small amount of energy is created and then the process being unclean. They are shooting the nucleus into parts instead of having a stable chemical reaction take place. Perhaps they need to have these small parts, electrons, protons, neutrons, that get blown apart to take place in an environment which will claim a stable chemical reaction to deal with the mess.

 

[chrispenycate]

Not very precise at all. Blindfold billiards. Mind you, at a molecular level, quite a lot of chemical reactions are like that, too.

But some of the waste products are seriously short lived (hence the radioactivity) and chemical solutions can't do much about that. Nor do we know all the things that are being generated (apart from alpha particles – nude helium. And you won't find anything much more resistant to chemical entrapment than that.)

Don't forget that, in order to achieve critical mass, a large percentage of the matter present has to be uranium, frequently very hot. Not convenient for adding chemical purifiers, even assuming we knew what was wanted, and that the elements involved were not violently modified by the neutron flux.

The independent particles; they are not chemical. Chemistry is the interaction of atoms and molecules, largely dependent on electron shells, and in nuclear reactions, we ignore electron shells; indeed in fusion, have disposed of them. So chemical solutions are not going to work. Electromagnetic ones might, but not on neutrons.

Not the same set of problems, and the solutions so far have been a bit crude. However, I'm not clever enough to point out obvious improvements. so I hesitate to go ultra, and rant against a solution which, while not perfect, actually works.

 

[Tinsel]

That would be a good book to write, that is, for someone who has first hand knowledge of the process, because it is not covered by theory. It is more of an application area or applied science. Obviously it is important.

How do they develop a technique to deal with nuclear waste, or even how is it handled to this day, keeping in sight mass to energy as a valid energy resource solution.

I'm under the impression that if they have nuclear plants, that they developed weapons or positioned for nuclear development in the days of the nuclear arms race, although the new age has come bringing with it closure in the form of alternatives such as converting the asset into energy production.

 

[Doctor Crankenstein]

Have you heard of synrock?

By using synrock you completely avoid groundwater irradiation problems that arise from normal disposal methods. Even if the stainless steel disposal container is compromised the synrock is practically impenetrable. Australia is essentially completely geologically stable as it sits solidly in the centre of the Indo-Australian Plate so the likelihood of the containers being damaged from seismic activity is infinitesimally small, if not zero.

Synrock is essentially a "Synthetic Rock", comprised of geo-chemically stable natural titanate minerals that have the ability to immobilize uranium and thorium for billions of years. These rocks can incorporate into their crystalline structure nearly all of the elements present in high-level radioactive waste and completely immobilize them. Synrock can take various forms depending on its specific use and can be tailored to immobilize different kinds of radioactive waste from nuclear power plant by-products to problematic cold war legacy waste.

According to Melody Carter: (Research Scientist, Institute of Materials & Engineering Science ANSTO) the synrock advantages were validated by the selection of synrock by the US Department of Energy for the plutonium immobilisation program in the late nineties. This program dealt with the immobilisation of surplus plutonium in the US and Russia (although with the change in US government this option is in suspension, highlighting the political nature of the industry). Currently there is a synroc plant being designed in Britain to immobilise 5 tonnes of plutonium residue waste at the British Nuclear Fuels Limited Sellafield Site. This plant will result in approximately £100 million cost savings from the current waste liability.

To safely dispose of radioactive waste you have to:

1. Immobilize waste in an insoluble matrix of synrock
2. Seal inside a corrosion-resistant container, e.g. Stainless steel.
3. In wet rock: surround containers with bentonite clay to inhibit groundwater movement.
4. Locate deep underground in a stable rock structure.
5. Site the repository in a remote location.

Australia has a plethora of suitable disposal sites, most notably the countless abandoned mines in Western Australia (The same place that the uranium is mined in the first place... how convenient).

Decommissioning can be solved in much the same way. A large portion of the plants can be reused in the construction of the nuclear fusion plants he has proposed, anything else such as the contaminated aluminium rods can be disposed of with synrock in much the same way as the waste.

 

[chrispenycate]

A lot of the NIMBY panic comes from transport hazards (including Greenpeace extremist trying, for the good of mankind, obviously, to derail trains carrying nuclear waste.

And there's a lot of energy tied up in that waste; probably more than was gained in generating it. Plus chemicals that don't exist anywhere else; with adequate separation, it could turn out to be a gold mine. Seems a pity to bury it in holes down under – or holes here, for that matter.

And if it were possible to transport the power conveniently, we could set our solar generators over the bits of Australia nobody wants, and give the roo fellas some shade. Otherwise, the 'mine it, enrich it, generate with it and then stuff it back into the holes it came out of' philosophy would tide us over for a good long time.

But fission produces very little waste, when compared with say, the ashes from coal-fired generators. It's just very unpleasant waste. And an awful lot of it is generated before the electricity starts flowing (actually, looking at slag mountains, I suppose that's fairly ordinary; but we don't transport that like the U238).

Obviously, I have a genius level solution to all these problems, but can't patent it as you have to be able to produce a working model. (and I admit there might be one or two tiny drawbacks ) So perhaps I'll write a science fiction novel about it.

No, that would come out all fifties, yay technology and humans irrelevant. I think I'll just wait for someone cleverer than me to come up with the idea.

 

[Tinsel]

Well as long as they stop dumping it in the ocean. Or they could send it all into outer space; there musn't be that much energy being produced.

 

[PTeppic]

What exactly does a nuclear power plant work on. Based on the information in your post it seems like they are able to generate power (as a byproduct?) but they are not able to convert atomic mass into pure energy. Are they making weapons down there or are they creating an energy supply, or is energy a byproduct as a result of some other purpose.

In the vast majority of commercial reactors, the purpose is to create energy, in the form of "pure energy" as you term it. However, that energy comes split into two forms, radiation and heat. A big problem is that neither of these is a usable form, e.g. electricity. The "inefficiency" in nuclear power generation (which is not only "on the table" but widely used in many countries) is that there's a huge waste of energy in converting the heat from a reaction into electricity (and the radiation isn't just unusable but dangerous too).

Going back to my first line, the UN keeps track of all those who can create nuclear weapons, and it's very much an old boys club: okay if you're already in but they don't want any new members, thank you.

 

[Doctor Crankenstein]

I'm an australian so I was talking from a 'having an australian nuclear power plant' perspective. Never meant to suggest transporting it from other countries to here...

And the 'roo fellas' don't need shade! They are in plague proportions at the moment. 10 000 Grey Roo's were culled last week...