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Nuclear power?
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sean
Downsizer Moderator

Joined: 28 Oct 2004
Posts: 42207
Location: North Devon

Posted: Tue Jul 05, 05 1:16 pm Post subject:

bagpuss wrote:

Northern_Lad wrote:

The waste could be water, but at the moment it's far more likely to be helium. The bigger the atoms you weld together, the harder it is, so it's being done with deuterium (an isotope of hydrogen: two neutrons and a proton) and adding a proton (helium = 2p+2n). In theory, you could end up with water (2 hydrogen + 1 oxygen), but it'd be darn tricky in practice.

that will be good though as we are running out of helium as its escape velocity is less than our gravity or something like that

And everyone will be able to talk in really high-pitched voices.

Jb

Joined: 08 Jun 2005
Posts: 7761
Location: 91ï¿½ N

Posted: Tue Jul 05, 05 1:45 pm Post subject:

bagpuss wrote:

JB wrote:

Except that it is much easier to contain uranium waste and its decay products. By their nature of being heavy metals they tend not to escape whereas carbon wants to merge into your body.

I actually don't think that is true. the nuclear waste produced by fission contains probably proportional numbers of alpha and beta emitters. The other downside is for uranium it takes far more decays to reach a stable product but in carbon 14 lose one electron via beta decay and it is stable and that is without taking in consideration the toxicity of nuclear waste aside from its radioactivity

My point was that if you are considering the danger of the radiation from nuclear waster or even just fuel then using the fact that proportionally coal releases more radition then it as a indicator that it is safer is a little meaningless as while the numbers do show that coal releases more beta radition through carbon 14-13 emissions taking that fact on its own is slightly meaningless.

I suspect I wasn't clear about my point. The waste products from nuclear power, while they are highly toxic and radioactive and have long decay chains and all the other problems that are undoubtedly true, appear in a form that can be contained. The waste fuel from a nuclear power station is containable. In fact sometimes it is processed into a glass form - non volatile, solid at all realistic temperature and while its highly toxic and radioactive it will just sit there as a lump. The waste fuel from a power station is either dispersed directly into the atmosphere or dumped as land fill and in either case is in a form which is readily absorbed back into the environment.

Its a bit like a car with a catalytic convertor. The car is cleaner but you are left with a highly toxic lump to dispose with at the end instead of having just dispersed it into the atmosphere.

bagpuss

Joined: 09 Dec 2004
Posts: 10507
Location: cambridge

Posted: Tue Jul 05, 05 1:52 pm Post subject:

Yes we are realising carbon 14 into the atmostphere which wasn't previously there but on the scale of issues with burning fossil fuels and the problems and pollutions it cause this will also be low on the list because compared to the other pollutants that burning fossil fuels produces carbon 14 isn't that much of an issue or danger but in nuclear fuel the radioactivity though is one of the primary concerns which is why I am saying its not meaningful to really compare them

Blue Peter

Joined: 21 Mar 2005
Posts: 2400
Location: Milton Keynes

Posted: Tue Jul 05, 05 2:00 pm Post subject:

Can I take a slightly different tack and look at things from an energy perspective rather than a waste perspective (though of course, there is a link).

One argument for nuclear power is that it doesn't produce carbon dioxide. This is more or less true of it's method of power generation, but not of its mining and transport of its fuel. I believe that if you add this into the equation, then there is a significant CO2 contribution, though still less than pure fossil fuels (but it's not zero greenhouse).

More importantly, nuclear energy is not renewable energy because it uses up its fuel, and, in general, as time goes on, it will become more difficult to get the fuel. At some point, indeed, it will take more energy to recover the uranium than the uranium will eventually produce (and the CO2 emissions will increase).

There are some estimates which suggest that this situation could occur fairly soon (e.g. see:

https://www.oprit.rug.nl/deenen/

and

https://afr.com/articles/2005/06/23/1119321845502.html

though I don't know enough to verify what they say).

In which case, I can't see much point in going for nuclear energy, leaving aside the waste issue. Far better to spend the money on energy efficiency and renewables.

Northern_Lad

Joined: 13 Dec 2004
Posts: 14210
Location: Somewhere

Posted: Tue Jul 05, 05 2:08 pm Post subject:

Blue Peter wrote:

In which case, I can't see much point in going for nuclear energy, leaving aside the waste issue. Far better to spend the money on energy efficiency and renewables.

Fission: I agree - it will only be a stop-gap, but generally cleaner than coal and the like.
Fusion: Not true - it's ingredients are all around us.

One thing that has just struck me is that coal powered stations burn coal (quick, aren't I?) at, say, 10 tonnes per hour. Now, the coal is ground into dust to make burning more efficient and reduce wasteage. At the end of the burn, very little of the 10 tonnes is left in the burner - where does it go? The only place I can think of it the atmosphere.

Jonnyboy

Joined: 29 Oct 2004
Posts: 23956
Location: under some rain.

Posted: Tue Jul 05, 05 2:20 pm Post subject:

JB wrote:

With respect I think that's incorrect. A lot of fuel is reprocessed through dissolving in acid. Technetium-99 is present in the waste and is one of the radioactive substances for which there is no known safe method for disposal. The result is that it is dumped in the sea from sellafield and can show up as far away as Norway or Russia. TC-99 has a half life of 200,000 years and the cumulative effects are unknown.

1996, concentrations of TC-99 in lobster, virtually zero.
2005, concentrations of TC-99 in lobster, 660 becquerels per kilogram.

European Union limted for radiation exposure in the event of a nuclear accident : 1250 becquerels per kilogram

Current concentration in wet seaweed at Sellafield discharge points: 17,000 becquerels per kilogram

Blue Peter

Joined: 21 Mar 2005
Posts: 2400
Location: Milton Keynes

Posted: Tue Jul 05, 05 2:21 pm Post subject:

Northern_Lad wrote:

Fusion: Not true - it's ingredients are all around us.

But going for fusion is a bit of a gamble, whereas wind turbines aren't (and wind is all around us - especially when I post

)

Peter.

bagpuss

Joined: 09 Dec 2004
Posts: 10507
Location: cambridge

Posted: Tue Jul 05, 05 2:29 pm Post subject:
Peter though isn't the reason nuclear is being considered is because that it isn't clear whether renewable sources like wind power even if setup large scale could actually cater for our energy needs? where as nuclear can and does in at least france

Northern_Lad

Joined: 13 Dec 2004
Posts: 14210
Location: Somewhere

Posted: Tue Jul 05, 05 2:32 pm Post subject:

Blue Peter wrote:

Northern_Lad wrote:

Fusion: Not true - it's ingredients are all around us.

But going for fusion is a bit of a gamble, whereas wind turbines aren't (and wind is all around us - especially when I post

)

I'm certainly not saying that we should only go with fusion. Wind, solar, tidal and wave are all all free at point of use, relatively easy to 'harvest' and shouldn't run out for a couple of billion years. Problem is, oil's cheeper.

Blue Peter

Joined: 21 Mar 2005
Posts: 2400
Location: Milton Keynes

Posted: Tue Jul 05, 05 2:38 pm Post subject:

Northern_Lad wrote:

[Problem is, oil's cheeper.

At the moment,

Peter.

Guest

Posted: Tue Jul 12, 05 3:30 pm Post subject:

I think anyone that argues that nuclear waste is less contaminating than coal waste has rather missed the point. Agreed there is quite a bit of background radiation near a coal pile, almost as much as in a granite cave. Its not the level of radiation thats the problem.
1) Buildup
The contaminents from nuclear fuel are known to get into the food chain, and when they do they buildup, seaweed might be low level contaminated but if you eat the fish which ate the seaweed you get a concentrated dose and you can't get rid of it.
2) Time
Exposure over time is the big problem yes you can contain nuclear waste "easily" and yes you can put it into inert glass (which btw is a fluid over 200,000 years) but that part of the world is then a no go for hundreds of millenia the alternatives are better

Northern_Lad

Joined: 13 Dec 2004
Posts: 14210
Location: Somewhere

Posted: Tue Jul 12, 05 3:35 pm Post subject:

Anonymous wrote:

I think anyone that argues that nuclear waste is less contaminating than coal waste has rather missed the point.

Quite right, but I don't think anyone here has.

nathanbriggs

Joined: 23 Mar 2005
Posts: 35
Location: Chester

Posted: Tue Jul 12, 05 3:42 pm Post subject:

that guest post was me (i forgot to login) in case anyone wants to flame me.

besides I think the important arguments are against nuclear actually on purely financial grounds. Most of our nuclear capacity reaches end of life in the next 15 years, the proposed solution from nuclear was to spend 20 billion to give 11 GW of electricity, but the should have started in 1995, if they start now it would arrive too late.

Worse than that you can't build a test nuclear reactor you have to build a real one, and the latest designs, which are supposed to be so much safer and better than chernobyl and other outdated technologies are just that theoretical designs, how do you test them? build one and see. So would you rather live next to an experimental reactor or any other sort of power station?

The best thing to do is spend money on research to develop a clean nuclear alternative. But imo to spend money on known BAD technologies is just foolish.

tahir

Joined: 28 Oct 2004
Posts: 45420
Location: Essex

Posted: Tue Jul 12, 05 3:49 pm Post subject:

nathanbriggs wrote:

The best thing to do is spend money on research to develop a clean nuclear alternative. But imo to spend money on known BAD technologies is just foolish.

I don't think you're wrong but aren't we going to need a stopgap if our energy requirements don't start declining?

I'm not pro nuclear, I'm pro reducing energy usage but that's not happening on either a governmental or personal level....

Jb

Joined: 08 Jun 2005
Posts: 7761
Location: 91ï¿½ N

Posted: Tue Jul 12, 05 3:55 pm Post subject:

Anonymous wrote:

You are right that it is not the level of radiation that is the problem. Hence the fact that coal produces more C14 and radiation from that than is emitted from a nulcear power station is not alone sufficient to condemn it. The fact that it dumps a few hundred million tonnes of slag, ash, spoil and CO2 into the environment is a different matter altogether.

In that respect nuclear power stations are less contaminating than fossil fuel power stations. I don't think that anyone would argue that nulcear _waste_ is less contaminating than fossil fuel waste but in normal practice is is contained in a manner that fossil waste isn't.

BTW glass is not a fluid it is an amorphous solid, that is to say a solid having no distinct crystalline form it will not even over 200,000 years flow away like water (see https://www.star-bits.com/ldglass.htm for examples of glass that are 28 million years old). Essentially glass is not a fluid or a solid but rather glass is glass.

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