Any ideas how to stop nuclear energy/fallout?

No.

Three feet of solid earth or a foot of water is supposed to provide as much protection as an inch of lead.

Note that several science fiction (and I use the term extremely loosely here) RPGs have postulated the idea of a field or shield wherein nuclear reactions could not be initiated. Of course, these fields or shields conveniently overlook the fact that if they shut down the possibility of close nuclear reactions they have rather nasty side effects on other nuclear reactions as well, particularly those keeping most of the individuals trapped inside those fields alive in the first place.

"Failure on your part to predict the potential side effects of an experiment that can have planetary-scale effects can most definitely result in my having and taking a direct interest in your future well being."

(Jason Carter, Pupae)

FOTSGreg said:

Three feet of solid earth or a foot of water is supposed to provide as much protection as an inch of lead.

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It's all about mass between the target and the emitter. Lead works well because its so dense, so you need less (volume) of it.

Note that several science fiction (and I use the term extremely loosely here) RPGs have postulated the idea of a field or shield wherein nuclear reactions could not be initiated. Of course, these fields or shields conveniently overlook the fact that if they shut down the possibility of close nuclear reactions they have rather nasty side effects on other nuclear reactions as well, particularly those keeping most of the individuals trapped inside those fields alive in the first place.

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Oh yes. It should be called a rule. Do not fuck around with the strong nuclear force.
Also, i'd say that if the technology is available to somehow locally alter the strong nuclear force to prevent decay, nuclear fallout really isn't even on the list of things to worry about.
On another note, Ghost in the Shell by Masamune has a a mention of nanomachines which are used to clean up fallout. Collecting radioactive material to clean up an area is a lot more believable (though those nanomachines could also be used in various manners for malignant mischief.

I recall a genuine scientific report in recent years regarding the control of radioactive decay on an atom-by-atom basis. Can't remember details or source, sorry, but it did turn out that the amount of energy needed was at least equal to that of the decay, making it essentially useless in practical terms.

It is probably possible to 'shield' yourself from harmful radiation with a monster magnetic field, but again, energy requirements would probably make 1m-thick lead walls a more realistic proposition.

Nuclear radiation is tricky because it comes in different kinds. The kind we worry most about is called ionising radiation, and includes alpha particles (charged bits of nucleus), beta particles (individual electrons), neutrons (uncharged bits of nucleus) and gamma rays (high-energy light).

The general aim in stopping ionising radiation is to give it something to hit and ionise that isn't yourself. Alpha particles can be stopped by metals, earth, enough water. They're charged, and you can also use strong electromagnetic fields to bend or deflect them. Beta particles are essentially electrons and lighter than alpha particles, so they can be stopped by a thinner layer of pretty much any of the above -- even your epidermis can stop a lot of beta radiation (and "beta burns" can make your epidermis slough away).

Neutrons are uncharged, and you want a thick layer of dense stuff to stop them. You do not normally want to use water to stop neutrons, because when neutrons hit water they tend to spray neutrons like shrapnel.

Like neutrons, gamma radiation is uncharged, and you want a thick layer of dense stuff to stop it. I'm not sure if you can play polarisation games with gamma, the way you can with visible light -- or if so, what material you'd use.

Fallout is made up of particles of radioactive dust and other heavy matter. Protective suits can help keep such dust away from you, but the real problem is that it makes its way into the food chain -- the water you drink and the food you eat. Filtering can help keep it out of drinking-water, but once it's locked into plant and animal tissue, I don't think there's much we can do other than not eat those plants or animals -- or else take medication for the effects of doing so.

Hope that helps.

The first book I read about this kind of question, was Alas Babylon by Franks. In it there is a scene, where days, weeks, or months, (I don't remember the time frame), looters raid stores. Those who raided jewelry stores and wore the jewelry were dead in a matter of days because the metal is HOT, as in it absorbed certain radioactive material and would be hot for thousands of years.

This made me think of what life would be like after a nuclear fall out. Even if you could protect yourself in a shelter or bubble, you could not leave the protection anytime soon because everything outside of it is contaminated. Homes, buildings, cars, water, the dust on the road, etc...

Not sure you could neutralize an area large enough to start farming again, or raising livestock. More than likely, survivors would move on to area's deemed safe and start again. But...would those who live in the safe area's accept everyone, or would it depend on what your skills are?

I don't mean this a derail --

But.

When I was in elementary school, from kindergarten through third grade, we had all sorts of drills -- including one for atom bombs that involved us huddling under our desks with our arms wrapped around our heads.

I've seen Hiroshima and Nakasaki photos of just that.

Medievalist said:

I don't mean this a derail --

But.

When I was in elementary school, from kindergarten through third grade, we had all sorts of drills -- including one for atom bombs that involved us huddling under our desks with are arms wrapped around our heads.

I've seen Hiroshima and Nakasaki photos of just that.

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Yes, I remember those days. I lived in the Midwest then, near minute men sites. We had lots of drills because we knew the area would be targeted. I later realized it was more so they could find us all in one spot instead of splattered all over the place from the blast and heat wave...

Zachariah said:

I recall a genuine scientific report in recent years regarding the control of radioactive decay on an atom-by-atom basis. Can't remember details or source, sorry, but it did turn out that the amount of energy needed was at least equal to that of the decay, making it essentially useless in practical terms.

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I'd like to know more about that - atomic decay is allegedly a "truly random" process (I'd like to know how they know that, but I'm not a physicist) and there's no way to slow it down that I've heard of. You can go ahead and make it happen by hitting the nucleus with a high-speed neutron, and that's exactly how a nuclear fission bomb works.

Zachariah said:

It is probably possible to 'shield' yourself from harmful radiation with a monster magnetic field, but again, energy requirements would probably make 1m-thick lead walls a more realistic proposition.

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As whoever said, a magnetic field won't stop or deter the uncharged particles, the neutrons and gamma rays. But I'm not sure just how far they go out through the air from the explosion. There's other things that can hurt or kill you - the heat, and the blast. Or indirectly - a building saves you from the direct blast, but then it falls down on you.

Medievalist said:

I don't mean this a derail --

But.

When I was in elementary school, from kindergarten through third grade, we had all sorts of drills -- including one for atom bombs that involved us huddling under our desks with are arms wrapped around our heads.

I've seen Hiroshima and Nakasaki photos of just that.

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I'm a little too young for for the get-under-the-desk drills though I later hard about them. I recall a third-fourth grade teacher - she was young, 20's, her husband was in the army, in Viet Nam. We (the class) were at lunch when the air raid siren on the school's roof went off, as it did every Wednesday at noon. Another student asked the teacher, innocently enough, "Why do they run that siren every week?" She answered, with fear in her voice, "So the Russians won't invade."

The answer was confusing at the time, but obviously she had grown up going through the under-the-desk drills, and her answer was a short-cut through the long story of the Cold War and Civil Defense.

Ruv Draba said:

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Pretty much correct on all counts except that neutrons aren't actually ionizing radiation (they're neutral, they don't ionize) and you switched the relative penetration of electrons and alpha particles (alpha is the least dangerous, actually not dangerous at all).

LOG said:

Can you...un-radiate something?
Or radiate it with something to neutralize the other radiation?

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You could theoretically use neutrons to change the atoms of radioactive isotopes into inert isotopes. Not a practical solution at all though, because if you can identify and target them that precisely, just removing the radioactive material physically would be much simpler.

thothguard51 said:

<snip>the metal is HOT, as in it absorbed certain radioactive material and would be hot for thousands of years.

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It's actually more a problem of secondary radioactivity. Fallout doesn't get absorbed by materials such as metals any more than "normal" dust, however neutrons hitting heavy elements can change those into radioactive isotopes. Generally less likely to happen to light elements but depends on the specific element hit (and neutron energy).[/quote]Not sure you could neutralize an area large enough to start farming again, or raising livestock.[/QUOTE]Interestingly enough, farming wouldn't be as much of a problem as eating the produce. Many plants are much more resistant to radiation than humans or animals.
You can actually protect plants from vermin by irradiating the fields just strong enough to kill bugs but not strong enough to kill plants.

benbradley said:

I'd like to know more about that - atomic decay is allegedly a "truly random" process (I'd like to know how they know that, but I'm not a physicist) and there's no way to slow it down that I've heard of.

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I'm curious too. The only thing affecting decay rates i've ever heard of is some research that found that heating radioactive elements to high temperatures (Sun temperatures, not Summer temperatures) appears to accelerate nuclear decay a bit. (a few percent bit, not a few times bit)
Which still boils down to it doesn't practically affect decay rates.

one of the first books I read about fallout of nuclear testing that was done in the fifties opened my eyes to nuclear bombs effect on enviroment. The book is "the day we bomb Utah" eye opening about the testing done above ground in the 50-60s. But also might shed light on fallout effects from a more realistic view point. "Food chain" and trickly down effect. Will have to advise some readers that everything in that book is truthful factual history. Sad but true what we have done and continue to do to our enviroment and people.

As another aside touching on radiation, Ernest Orlando Lawrence used to carry around a nickel-sized piece of plutonium in a cigar box. They had it and the cigar box on display under glass in the main lobby of the director's building while I was there for almost 5 years.

Legend has it that the cigar box alone was enough to shield almost all the radiation.

We once had someone leave radioactive samples (iodine as I recall) intended for use by the medical cyclotron facility at our main guard shack. When hazmat was called they took a look, shrugged, and left with it in their pants pocket.

As a comparison, an accidental spill of mercury closed the entire new nanotechnology building for 6 weeks while the tiny spill and all remnants (that had been tracked throughout the building by several scientists and grad students) were cleaned up.

Any theories on how such a thing could be accomplished in a specific area? Also, are there any theories on how to absorb or halt radiation?
God =P
Kidding.

There's a couple things that my imagination toys with. If you don't bury the area under the earth's surface, I would say there's two parts of science that you would have to look into: Empty matter (which there isn't too much information outside of theories and fuel use -- so you've got lots of room to play with), Magnetism (forcing north/south poles to switch could let the radiation leak out, but then you'd have to deal with all the shit from the atmosphere leaking in, which -- would probably lead to mass mutations), and last but not least, you can kinda make up something. Perhaps make up a new element that goes in the periodic table which soaks in radiation like a sponge. I dunno.

If there was something reasonable, I'm pretty sure it would be close to common knowledge (like lead). So you might be forced to use your imagination a bit. =)

As another aside touching on radiation, Ernest Orlando Lawrence used to carry around a nickel-sized piece of plutonium in a cigar box. They had it and the cigar box on display under glass in the main lobby of the director's building while I was there for almost 5 years.

Legend has it that the cigar box alone was enough to shield almost all the radiation.

We once had someone leave radioactive samples (iodine as I recall) intended for use by the medical cyclotron facility at our main guard shack. When hazmat was called they took a look, shrugged, and left with it in their pants pocket.

As a comparison, an accidental spill of mercury closed the entire new nanotechnology building for 6 weeks while the tiny spill and all remnants (that had been tracked throughout the building by several scientists and grad students) were cleaned up.

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:O That's pretty cool.

FOTSGreg said:

As a comparison, an accidental spill of mercury closed the entire new nanotechnology building for 6 weeks while the tiny spill and all remnants (that had been tracked throughout the building by several scientists and grad students) were cleaned up.

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That's why i'm kind of surprised plutonium would be treated casually. While not radioactively hot enough to be dangerous (gamma radiation is what's most dangerous to humans, but it's not relevant for creating a bomb) the stuff is highly toxic, and actually quite volatile.

From advice my dad gave me on the subject (was a nuclear chemist in the US submarine force).

Alpha = Harmless unless ingested, then extremely deadly. This is how that russian guy got killed a few years back by plutonium. Can be blocked by dead skin.

Beta = Mostly harmless unless very intense, small amounts can be ingested with out any real harm. Because it's just electrons they can usually penetrate a bit better than alpha particles.

Gamma = Dangerous.

Neutrons = Deadly. More dangerous than gamma rays because the neutrons can penetrate relatively well, but have the mass to do damage to cells.

Apparently, it's relatively safe in metallic form. Of course,I always half-suspected they weren't actually displaying the real metallic plutonium plug although I was assured that it was the real thing (the same lab displayed Lawrence's actual gold Nobel prize medal in their (unsecured) museum until it was stolen by an insider (it was recovered a week or two later).

DOE labs, both types, do all kinds of things that make security professionals grasp at their chests in panic over.

Dommo said:

Gamma = Dangerous.

Neutrons = Deadly. More dangerous than gamma rays because the neutrons can penetrate relatively well, but have the mass to do damage to cells.

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Kind of. Whether neutron or gamma are more dangerous depends mostly on the energy of the neutrons. Fast neutrons won't interact much, and are not very likely to impact and change atoms inside your cells. While gamma photons can't cause any nuclear change to atoms, they still can ionize them, even otherwise stable atoms locked in molecules (say, DNA) because they're so energetic.
Of course, in the long run neutrons are the really nasty type of radiation, because they cause secondary radioactivity in other materials.

Found it!

The Quantum Zeno Effect

Executive summary: Keep an unstable particle (like Pu[SUP]238[/SUP]) under continual observation, and it should never decay.

I am assured, by people who should know, that this is not some fancy quantum theory and has been observed in real experiments. But, as I remembered, is useless in practical terms due to the energy costs of observing every particle continuously.

As far as i know, that only works on quantum decay of particles. I.e. it shouldn't work on radioactive decay of atom cores.

Has anything come from the observations of a weak seasonal variation in radioactive decay? Has it been confirmed, refuted or still unknown? Initial reports indicated a dependency on earth-sun distance or solar activity. Google "seasonal radioactive decay rate" for more info.

In any case, at this time it should provide a jumping off point for a SF story.

I'm jumping in this thread way late. The issue interests me (as I assume it does others) because it's a big problem with long term space travel. It's no fun to have your main character get half way to the crisis in the story and die of bone cancer or some such. Damn.

It looks like the issues are mainly gamma (high energy photons) and slow neutrons. Of these, it's mainly gamma rays that are at issue for space travel (Lhun, please correct me if I'm wrong). The problem is damaged cell and genetic material that results from ionized atoms and radicals in complex molecules like, say, DNA. So, whaddawe do to get of the Earth? Seems to me that the shortest path to a technobabble solution is a medical one--modified body chemistry (read, white cells) that can recognise and destroy damaged cells that result from the radiation. The downside would be increased metabolic cost of maintaining a high level immune system, but it seems plausible to me. Any thoughts about why it wouldn't work?

While the hard cosmic background radiation certainly is a problem in space travel, it's less so than particle impacts, since the latter become much more dangerous the faster the ship goes, while the former become only marginally so.

Lhun said:

While the hard cosmic background radiation certainly is a problem in space travel, it's less so than particle impacts, since the latter become much more dangerous the faster the ship goes, while the former become only marginally so.

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Thank you, Lhun. I always appreciate your insights. Could you elaborate a bit about particle impacts? That sounds like we are getting away from the concept of radiation into micrometeoroids and interstellar hydrogen. Wouldn't physical barriers be effective against such, and wouldn't the direction of travel be the most important factor for designing the protection?