just sticking these links here as the appear to be the most accurate/least media biased/regularly updated sites I've seen so far and I'm tired of searching through this thread to find them:

http://www.iaea.org/newscenter/news/tsunamiupdate01.html
http://mitnse.com/
http://www.world-nuclear-news.org/default.aspx

I'm talking about an originally non-radioactive material radiated with radioactive radiation.
So, can atoms break/"mutate" because of alpha/beta/gamma radiation? So that they may become radioactive?

He already answered your question pretty well, if you read what he wrote

Alpha/Beta/Gamma can only ionize your atoms to make you sick.

Neutron radiation though, which occurs in reactors, can irradiate non-radioactive material, so that it becomes radioactive itself.
The process is called neutron activation, and you can read some about it here:

http://en.wikipedia.org/wiki/Radiation
http://en.wikipedia....tron_activation

I guess you misunderstood the question (which caused rate-down).

Not me. Aren't we glad downvotes are back...

So, can atoms break/"mutate" because of alpha/beta/gamma radiation? So that they may become radioactive?[/quote]
Of course. Atoms are protons, neutrons and electrons held together by nuclear (from nucleus) force. If hit, they may be smashed.

Radiation comes in many forms, but one relevant here is alpha, beta or gamma. Alpha is helium nucleus, beta is neutron and gamma is electron. As such, what is called radiation in this context are actual tangible particles, same as parts of atoms. All of these fall under ionizing radiation.


Assuming you have a glass of pure H2O. That cannot change to suddenly become radioactive. But, if exposed to radiation of adequately high energy, some of the H and O atoms will be smashed. The result will be something smaller, perhaps stable elements, perhaps unstable. During the process, some of alpha, beta or gamma particles may be released as well. This in itself does not mean material became radioactive.

If any of the results here are unstable elements, they will fall apart on their own, spontaneously. When this occurs, same process will occur. Atom will fall apart, possibly releasing some alpha, beta or gamma particles.

This later process is what defines radioactive materials - unstable isotopes which emit ionizing particles. Other sources are cosmic radiation, electromagnetic spectrum, photons, ....


So if irradiation of H2O causes some of those atoms to break down into unstable isotopes, the water will have become radioactive, since it will be emitting ionizing radiation even after irradiation ends. But the chemical composition will no longer be pure H2O. Some of those atoms will be broken down into other elements and chemical composition will change. U-235, after the end of decay chain becomes lead, it just takes millions of years.

In nuclear warheads one of bigger problems is maintenance of plutonium. Since some of the isotopes used have short half life, the chemical composition of warheads keeps changing. So all warheads need to be maintained (somehow) to correct for this, or that nice little nuke from the 50s fired today would fizzle.

Alpha is helium nucleus, beta is neutron and gamma is electron. As such, what is called radiation in this context are actual tangible particles, same as parts of atoms. All of these fall under ionizing radiation.

AFAIK Beta is electron and gamma is photon. And yes, they are ionizing radiations, but being ionized is pretty far from being radioactive. And AFAIK they are not powerful enough to destroy/modify the nucleus. The neutron can fuse with the nucleus, but AFAIK neutron radiation is not emitted when a nucleus decays spontaneously.

So I'm not convinced about the radioactivity part, but I am, about the neutron radiation (which is maybe happening in that reactor)

If I remember my physics, Alpha is a helium nucleus (a helium atom, but without any electrons), beta is neutrons and gamma is electromagnetism.

The alpha is by far the biggest particle and so does the most damage as it smashes into other atoms (including the DNA in your cells, which is how radiation gives you cancer). The gamma is the least destructive although it's far from 'safe' and is still destructive at high intensities.

The natural decay of any unstable nucleus will release either alpha or beta radiation, as well as a bit of gamma and turn the atom it hit into a different type of atom, for example Uranium-238 is unstable and decays naturally into a helium nucleus (alpha radiation) and a Thorium-234 atom, and also a squirt of gamma radiation as the decay occurs. This Thorium nucleus is also unstable and will naturally decay into a neutron (beta radiation) and a Protactinium-234 atom. And so on. The full chain for Uranium-238 is here: http://en.wikipedia....ivity_and_decay When we say a substance 'is radioactive' it means it is naturally decaying into other atoms and flinging out neutrons and helium nucleii which if you get it the way can break apart or otherwise alter the atoms in your body which is why it's dangerous.

When things decay, the alpha and beta particles they decay into are flung off at high speed and can smash into other atoms. When this happens, the atoms they hit can absorb and join onto the particle (fusion) or break apart into smaller particles (fission), both events changing it into a different kind of particle. As Antheus says, these new particles may or may not be unstable and decay further. The smash is also likely to to produce more high-speed alpha or beta particles which can smash into further atoms - casuing a chain reaction which can be harnessed to produce electricity or make a *really* big bang, depending on your intent.

If I remember my physics, Alpha is a helium nucleus (a helium atom, but without any electrons), beta is neutrons and gamma is electromagnetism.[/quote]

AFAIK Beta is electron and gamma is photon. And yes, they are ionizing radiations, but being ionized is pretty far from being radioactive... neutron can fuse with the nucleus, but AFAIK neutron radiation is not emitted when a nucleus decays spontaneously.

Bleh, ignore that. I was thinking of reactions inside reactor and miswrote. Yes.

. And AFAIK they are not powerful enough to destroy/modify the nucleus. The [/quote]Depends on energy. A nuclear accelerator is used to smash just about anything using several types of particles. In original question you asked about possibility of water begin radioactive, which can occur.

So I'm not convinced about the radioactivity part, but I am, about the neutron radiation (which is maybe happening in that reactor)[/quote]
The point I was trying to make was towards the "pure" radiation. There is no such thing.

Matter is radioactive when its composition changes. Oxygen atom does not somehow magically become radioactive. It can however be either smashed into other atoms or it can change into an isotope.

Chemically pure H2O can be made radioactive. What kind of irradiation and what energies it would take however is beyond me. But whatever the end result of such exposure will be, the contents will no longer be same atoms and molecules that were in original H2O. At least some of them will need to change.

As for Japan reactor - the sea water is probably irradiated, but it is the Na in salt that will become by far most active. The rest, such as H2O, even if they do activate, are negligible as far as total mass goes. Still, compared to everything else here, this type of irradiation is negligible.

[quote name='Prefect' timestamp='1300350308' post='4786912']
Finally, there is no way that nuclear power generation should be in the hands of private corporations. The free market has pretty clearly decided that the risks associated with it are so great that they cannot be insured, and so the risk is squarely placed on the general population, while the financial reward is in the hands of a few. This kind of moral hazard is simply inacceptable. If nuclear power is at all an option, it must be operated on a non-profit basis.

How is that any different than fossil fuels? We have just as much evidence to suggest that fossil fuels can be just as harmful. In fact, I wouldn't be surprised if fossil fuels were directly responsible for more destruction than nuclear power plants.
[/quote]
It is different from the point of view of the insurance companies. That should really tell you everything you need to know, because those people basically breathe risk assessment. Besides, fossil fuels do have the same problem with risks that aren't widely discussed, as was seen in the Gulf of Mexico.

But that's a red herring anyway. This is not nuclear vs. fossil. It's nuclear vs. solar.

[quote name='Alpha_ProgDes' timestamp='1300376464' post='4787050']
Is the reactor exposed (as in you can see it from the helicopter) or something? It seems that dropping water on the roof isn't very effective....

yes you can actually see from pictures that the protective buildings around some of the reactors are destroyed. They even think there's a crack in the bottom of one so they question whether pouring water into what's left of the container will do anything.[/quote]No, the reactor is not exposed and the buildings' containment walls aren't destroyed (except building 2, which is assumed to have an unidentified breach somewhere in it's airtight seals). The destruction you can see is the regular-strength walls that were built around the 2m thick concrete shields.

Helicopters aren't dropping water onto the reactors - they're dropping water onto the cooling ponds used to store spent fuel rods (i.e. nuclear waste), which happen to be located on the roof of the reactor buildings. The ponds are either emptying through a leak or through evaporation, so are being refilled via hoses and helicopters. If the ponds run dry, the nuclear waste could be released into the atmosphere (as has already happened somewhat in building 4 where the waste may have been burning). These ponds are usually kept at 25ºC, but yesterday they were up to 60-80ºC (100ºC is boiling point for the Imperialists among us )

These ponds are probably a bigger threat than the reactors at the moment, because they're not contained inside 2m thick concrete buildings like the reactors are.

This is a crazy statement, but if space development actually flourishes, in the future, we could dispose of nuclear waste into space. Haha. Well, afaik people can bring cameras into orbit and program them to take pictures from space while hanging onto those hot-air balloon-like structures, so there might be a good chance of sending the waste into some mechanism like that IN THE FUTURE.

in this article, they eventually decay, but can potentially take a really really long time. so they contain it somewhere where the waste will not disturb/be disturbed while slowly decaying.

We may have to worry though if the container does get disturbed by people or disturbs the ecosystems around it

Japan is third largest economy in the world. What do you suggest they use to replace around 20GW of power with?
Serious question - what is the alternative. And nothing hypothetical/in theory/looks nice. The stuff that can be built today, by a company that has built stuff like this, that can supply 20GW of constant, industrial grade (not residential) power. That means individual megawatt consumers.

Warning: your statement makes no sense. "customers" don't care about installed power (GW) they care about energy they need (TWh). As such, your question is not serious. If you want to make it serious add serious constraints such as (in no particular order):

1. How much time to build?
2. How much money to build?
3. How much uptime year?
4. How much energy output per year?
5. How much money to run (maintainance)?
6. How much money to dispose?
7. How long must be able to operate (technical life)? 20y? 40y? 60y?
8. Are CO2 emissions a problem?
9. Do we want to consume little amount of terrain? How much?
10. Do we need to centralize production? Perhaps we want a fleet of smaller, units instead?
11. How reliable must it be against earthquakes/hurricanes/terrorism?
12. Do we need to cover base load or peak load?
13. Are we talking about day peak or year peak?
14. Do we need to route the energy to a specific section of the grid?
15. Do we need to move generator far away from consumption?
16. Is there any hazard to public health we are willing to accept? Is there the case to move this away from population?
17. How do we want to fund this? (government takes direct action)
18. Do we want to subsidize this? (private citizens takes direct action)
19. Are technical risks well known? Can we have sufficient guarantee issues will be promptly solved? (this is very much like risk assessment in SW development cycles)
20. Any economical risks?
21. If it cannot be built today, can we arrange to build it tomorrow? Different wording: do we want to do research so this becomes possible in the short term? (short term is "a couple of years" in this case)
22. Do we need it RIGHT NOW?

Fill the matrix, then we can talk.