Nuclear Power (merged threads)

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Re: Nuclear Q&A with Industry

Postby Barthanatos » Fri May 23, 2008 7:32 pm UTC

Mr. Beck wrote:How toxic are the fuel rods chemically? I know Uranium/Plutonium is highly hazardous, but does the ceramic neutralize that?

http://msds.chem.ox.ac.uk/UR/uranium.html

Just do a Google search for "MSDS plutonium" and you'll get more. MSDS is a Material Safety Data Sheet, and lists hazards for various chemicals. It may not exactly quantify the amount of toxicity, or in any way explain chemical reactions going on.

Also, why is there not more discussion of Thorium as a fuel?


I'm going to guess that it is because U-235 is a better thermal fuel. I don't remember off the top of my head what the factors are that affect usefulness of a material as a thermal fuel, unfortunately. Natural abundance, cross-section for absorption, and half-life come to mind, but don't quote me on that. It's been about ten years since I was trained on that, and such matters of theory are not applicable to day-to-day operation of a nuclear power-plant (see my profile).

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Re: Nuclear Power, what's your issue with it?

Postby Mettra » Fri May 23, 2008 11:55 pm UTC

zenten wrote:Solar power will one day be the main replacement for grid power, at least in my opinion.

It is no where near able to do that. Right now the environmental cost alone for making that many solar panels (and of course disposing of them when they break down, and replacing damaged parts, etc), and taking up land to use them makes them worse than nuclear, at least in most places.


From the stand-back point of view, everything except perhaps the heat of our planet's core boils down to solar power. Inevitably we will get to a point where we draw our energy directly from sol, but that point is a while away. It probably won't look like solar panels either, we'll do something more efficient like have giant space mirrors boil water or something to spin turbines - but I'm no engineer when it comes to that kind of stuff.

For now, our supreme number one bet is on nuclear fission. Fusion is perhaps a short way off, perhaps a long way off. We have fission right now, and if we can build a 26km gun that fires proton beams 100m under the ground and collides them at .999c, by god we can build an airtight nuclear plant. From the standpoint of modern engineering technology/capability, it'd probably be safe to have mini-reactors in apartment complexes or city blocks. We are so far advanced beyond even 10 years ago, we make it look like living in caves. Today we don't just use plutonium and uranium, we have reactors that run on all kinds of materials, reactors that 'create' their own fuel or use several types of fuel, reactors that run on the WASTE products of other reactors!, self-safety designs with a negative temperature coefficient of reactivity - this is the space age for nuclear reactors. Thank god (in a way) for Chernobyl and all the terrible mistakes we made because it kicked us in the ass and made us get serious about building these things safely and taking their operation seriously.

Anybody who is seriously concerned about the safety of building a nuclear reactor (even in your metaphorical back yard) fails at statistics - you're more likely to die from worrying about it than to actually die from it. Even in the US, where regulation is a four-letter word, nuclear reactors are extremely heavily regulated. Nuclear materials are extremely heavily regulated. The construction and maintenance of nuclear plants is constantly under oversight.

Yes, there is a chance that you will die. Yes, there is a chance that some horrible worst-case scenario will cause massive fatalities and untold environmental damage. But you're probably about as likely to quantum tunnel through your front door.

The piece of the puzzle that we do need to worry about is waste management. Unfortunately, a lot of 'waste' these days is wasted. It could be used in several reactor designs. But there is some waste that we haven't found a good way to deal with. Further advances in engineering will iron these issues out. The problems caused by this kind of waste, actually, are less ominous than the problems caused by fossil fuels. We are slowly taking away our ability to survive on this planet by changing the conditions such that the air is an intolerable mix of gases. Most of the waste produced by a nuclear plant is steam which, as the astute among you know, is just water.
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Re: Nuclear Q&A with Industry

Postby Vaniver » Sat May 24, 2008 5:04 am UTC

endolith wrote:Good luck persuading people that they don't have to worry about radiation from nuclear power plants. I think it's a better tactic to show them the much larger amount of radiation coming from the alternatives.
The thing is, you run the risk of people going "what? Airplanes are more of a radiation risk than nuclear plants? I'm never flying again!"

It's better to just do comparisons between background, power plants, and risk thresholds.
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Re: Nuclear Power, what's your issue with it?

Postby Minerva » Sat May 24, 2008 8:46 am UTC

Ashbash wrote:I understand that nuclear power > coal usage.

My only problem is that it's still not a renewable resource and there's the issue of waste products. It seems that there is a high percentage of people on the fora who argue for nuclear power, heart and soul. I just want to know, why isn't solar power considered much? Or is it considered ineffiecient/expensive or something? Because for me, solar power is the way to go (at least once it becomes a bit more effecient and compact etc), and the only reason I'm not a strong advocate of nuclear is that solar energy is completely 'renewable' in the sense that once it is gone, so are we, and that you can have solar panels on everyone's house (but you can't have personal nuclear reactors etc)



The whole argument of "oh, but it's still a finite, non-renewable resource" is nonsense.

There's no such thing as "renewable" energy, if you try and use some literal, meaningful definition of "renewable". That's really nothing more than a restatement of the second law of thermodynamics.
Eventually, the hydrogen in the sun will run out. Eventually, the radiothermal heat inside the earth will decay, and eventually, all the free energy in the universe will be exhausted, and the universe will die.

Some physicists have estimated that the efficient use of uranium, plutonium and thorium - not ridiculous once-through fuel cycles - will provide an energy resource that will last for approximately the same length of time as the hydrogen in the sun. You don't get much more "renewable" than that.

Nuclear waste is not a substance - it's something that certain stupid governments do, with stupid, grossly inefficient, once-through LEU fuel cycles in light water reactors, and no recycling of fuel.
If nuclear waste is such a problem, then stop wasting it!

Is solar power inefficient and expensive? Yes!

A typical nuclear power plant produces about 1 GW of power output, with a capacity factor of about 90%. (i.e. the average power output, averaged over a long period of time, is 90% of the name plate design power).

Now, think about the sheer number of solar collectors, and the sheer amount of area, needed to collect 1 GW of power from the sun. Now, you have to be able to store that energy, to be able to provide energy with a high capacity factor, say 90%, to make it comparable with nuclear power.

Since the solar energy reaching the Earth is intrinsically intermittent, you need lots of extra capacity, several times more, to give you the same amount of capacity, with any reasonable capacity factor.

When you consider how much it costs to deliver solar energy on this scale, it's frightful. It just doesn't scale up competitively.

You've got to compare one gigawatt-year per year of energy from apples to one gigawatt-year per year of energy from oranges. Only then do you see how these things truly compare.

As far as isolating radioactive waste from the environment over long time scales is concerned, it is, scientifically and technologically, a completely solved problem. We know how to do it.
Basically, we just do it the same way nature has been isolating nuclear reactor byproducts from the environment at Oklo for the last two billion years.
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Re: Nuclear Power, what's your issue with it?

Postby Izawwlgood » Sat May 24, 2008 5:34 pm UTC

Exacting and processing uranium is not a zero-cost operation. I just want to point that out.

Solar power is certainly not a zero-cost operation, and is in it's current stages, wildly inefficient, but solar panels require significantly less maintenance then does a nuclear power plant, and takes advantage of an otherwise wasted power flux.

Don't dismiss either.
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Re: Nuclear Power, what's your issue with it?

Postby Vaniver » Sun May 25, 2008 3:05 am UTC

Ashbash wrote:I just want to know, why isn't solar power considered much?
Nuclear fission: operational, safe, and economical for 50+ years. Solar power: semi-operational, not as safe, not economical, not aligned with demand. It might be competitive in ten-thirty years; but it's not now.

Izawwlgood wrote:solar panels require significantly less maintenance then does a nuclear power plant
Less maintenance per what? Per watt of power? I find that hard to believe, given the sheer size difference between a GW solar power plant and a GW fission power plant.
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Re: Nuclear Q&A with Industry

Postby Mabus_Zero » Sun May 25, 2008 8:58 am UTC

Vaniver wrote:
endolith wrote:Good luck persuading people that they don't have to worry about radiation from nuclear power plants. I think it's a better tactic to show them the much larger amount of radiation coming from the alternatives.
The thing is, you run the risk of people going "what? Airplanes are more of a radiation risk than nuclear plants? I'm never flying again!"

It's better to just do comparisons between background, power plants, and risk thresholds.


That reminds me of my personal thoughts on Fusion Reactors, and slaying the Atomic Boogeyman.

Anyone interested in starting another thread along those lines?
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Re: Nuclear Q&A with Industry

Postby endolith » Sun May 25, 2008 3:09 pm UTC

Mabus_Zero wrote:That reminds me of my personal thoughts on Fusion Reactors, and slaying the Atomic Boogeyman.

Anyone interested in starting another thread along those lines?


You mean the reactor that you have to replace every few years because it's embrittled by radiation?

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Re: Nuclear Q&A with Industry

Postby TheStranger » Sun May 25, 2008 9:29 pm UTC

Mabus_Zero wrote:That reminds me of my personal thoughts on Fusion Reactors, and slaying the Atomic Boogeyman.


The problem is that we are decades away from a stable fusion reactor, and maybe a century or more from viable commercial application.
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Re: Nuclear Q&A with Industry

Postby Mabus_Zero » Sun May 25, 2008 9:34 pm UTC

A limitation in the structural strength of existing materials could easily enough explain the questions I have on why ITER hasn't taken off yet. Does anyone have reliable information on that particular concept? I'd like to patch up holes in my existing knowledge, if possible.
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Re: Nuclear Q&A with Industry

Postby basher2 » Sun May 25, 2008 10:14 pm UTC

Take a look at the ITER website. They explain some of the issues, but not in very satisfying detail. What they do show is the amount of money being thrown at the project (I think its around $10 billion). Some of the issues involve some of the issues inherent in using a tokomak fusion reactor. Such as the need for extremely high, DC currents (several thousand amperes in the much smaller S-TORM reactor at my school). This necessitates huge capacitors, and a lot of safety measures. Another is the production of plasma, and its injection into the toroid. This is an area which has seen some significant progress at my school (University of Saskatchewan).

For the uninitiated, ITER is planned to be a huge tokamak reactor, which basically means a huge toroidal (donut shaped) magnet which is used to magnetically confine dueterium and tritium nucleii closely enough that strong molecular forces take over, and a helium nucleus is formed. This is an exoenergetic reaction. Enough so that it is economical to produce the heavy water needed for the reaction to take place. However, it has not yet been demonstrated in a setting large enough, with a large enough supply of the plasma to produce a sustainable reaction. It is hoped that ITER will be the first. Construction is supposed to begin this year, according to the website, with plasma being produced in 2016. The relative success of this will determine how far beyond that any commercial applications would be possible. 2020 would be very optimistic. Maybe ridiculously so, but well short of the hundreds of years. This is probably the wrong forum topic for this, however, since fusion is sort of the opposite of the fission this topic is based on. However, it is still a nuclear reaction, so maybe it does belong, after all.

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Re: Nuclear Q&A with Industry

Postby MotorToad » Sun May 25, 2008 11:26 pm UTC

As far as nuclear power for transportation, I think it's been covered pretty well: It doesn't work on land. I did want to add that one of the projects the gov't took on in the radiation-happy '50s was a train car reactor for the army to use as a portable power source, and that didn't pan out (ooh, ore mining pun! :)). I can't recall what the main problems were, but I'm pretty sure it was a feasibility/cost/safety/weight issue like any other land-based portable unit. The indefinite supply of cooling water is a bigger thing than you'd think.

The rest of this I've posted previously in another thread, but it seems very topical here.

From http://www.uihealthcare.com/topics/medi ... ation.html
Background radiation accounts for an individual receiving, on the average, about 300-350 mrem each year. For example, a cross country airplane flight results in a dose of 4 mrem per trip. A routine chest x-ray is about 10 mrem per film. Smoking 1.5 packs of cigarettes daily exposes the individual to about 1300 mrem per year.


"Unnatural" background radiation:

Living in a Brick House Uranium and Thorium 75 mrem/year

Watching TV Low Energy X-rays 30 mrem/year (Yay for LCD!)

Cooking/Heating with Natural Gas Radon 9 mrem/year

Natural background radiation:

Cosmic: Protons; ElectronsNeutrons; Muons 26 mrem/year (at sea level) 50 mrem/year (Denver, CO)

Terrestrial: Thorium; Radium; Polonium-210; Lead-210, Potassium-40 16 mrem/year (Gulf Coast), 30 mrem/year (Iowa), 63 mrem/year (Rocky Mtns.)

Internal: Food, Milk, Water Potassium-40; Lead-210; Polonium-210 39 mrem/year

Atmospheric: Air Primarily Radon 200 mrem/year
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Re: Nuclear Q&A with Industry

Postby Mabus_Zero » Mon May 26, 2008 1:15 am UTC

basher2 wrote:Take a look at the ITER website. They explain some of the issues, but not in very satisfying detail. What they do show is the amount of money being thrown at the project (I think its around $10 billion). Some of the issues involve some of the issues inherent in using a tokomak fusion reactor. Such as the need for extremely high, DC currents (several thousand amperes in the much smaller S-TORM reactor at my school). This necessitates huge capacitors, and a lot of safety measures. Another is the production of plasma, and its injection into the toroid. This is an area which has seen some significant progress at my school (University of Saskatchewan).

For the uninitiated, ITER is planned to be a huge tokamak reactor, which basically means a huge toroidal (donut shaped) magnet which is used to magnetically confine dueterium and tritium nucleii closely enough that strong molecular forces take over, and a helium nucleus is formed. This is an exoenergetic reaction. Enough so that it is economical to produce the heavy water needed for the reaction to take place. However, it has not yet been demonstrated in a setting large enough, with a large enough supply of the plasma to produce a sustainable reaction. It is hoped that ITER will be the first. Construction is supposed to begin this year, according to the website, with plasma being produced in 2016. The relative success of this will determine how far beyond that any commercial applications would be possible. 2020 would be very optimistic. Maybe ridiculously so, but well short of the hundreds of years. This is probably the wrong forum topic for this, however, since fusion is sort of the opposite of the fission this topic is based on. However, it is still a nuclear reaction, so maybe it does belong, after all.


Excellent. Good to know that according to you at least, my knowledge base is roughly more-or-less accurate. Do you have any resources I could peruse beyond the official ones and wikipedia, or perhaps some unusual terminology I should take a look at? I have a writing hobby for which I like to have my science as accurate as possible.
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Re: Nuclear Q&A with Industry

Postby basher2 » Mon May 26, 2008 3:26 am UTC

I'd start at the ITER site, and look at the contributing partners websites, as a beginning. Then, because I attend the school, maybe U of S website (usask.ca), and look up plasma research, especially anything by Dr Akira Hirose. I know there is significant work being done throughout the EU, especially France and Germany, as well as Japan. Looking up as much of the actual scientific papers as possible is a good bet. The best thing would be to actually meet someone who is doing work in the area, because they always seem willing to talk about their work. A lot of places with active research (usually that means a Tokomak reactor) offer tours to the public to raise awareness. That might be a way to do some research, and actually meet someone who would know more than my pretty feeble amount.

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Re: Nuclear Power, what's your issue with it?

Postby zenten » Mon May 26, 2008 1:49 pm UTC

Izawwlgood wrote:Exacting and processing uranium is not a zero-cost operation. I just want to point that out.

Solar power is certainly not a zero-cost operation, and is in it's current stages, wildly inefficient, but solar panels require significantly less maintenance then does a nuclear power plant, and takes advantage of an otherwise wasted power flux.

Don't dismiss either.


I'm willing to bet that per (consistent) watt the environmental damage from harvesting the components to make (and maintain, and dispose when they break down) solar panels and the space they take up is orders of magnitude worse than the environmental cost from the same with nuclear power, at least when it comes to things like powering cities.

Solar of course is good for things like calculators, and stop lights in rural areas.

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Re: Nuclear Power, what's your issue with it?

Postby zealo » Mon May 26, 2008 3:30 pm UTC

have you ever used a nuclear powered calculator though? how can you judge which is 'better'? :P
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Re: Nuclear Q&A with Industry

Postby endolith » Mon May 26, 2008 4:21 pm UTC

And in the maybe-fringe-maybe-not world, you've got Bussard and his Polywell fusion reactor, which he always hoped could produce energy from the low-neutron proton-Boron11 reaction and generate electricity directly from the motion of charged alpha particles.

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Re: Nuclear Power, what's your issue with it?

Postby Mettra » Mon May 26, 2008 4:53 pm UTC

zenten wrote:
Izawwlgood wrote:Exacting and processing uranium is not a zero-cost operation. I just want to point that out.

Solar power is certainly not a zero-cost operation, and is in it's current stages, wildly inefficient, but solar panels require significantly less maintenance then does a nuclear power plant, and takes advantage of an otherwise wasted power flux.

Don't dismiss either.


I'm willing to bet that per (consistent) watt the environmental damage from harvesting the components to make (and maintain, and dispose when they break down) solar panels and the space they take up is orders of magnitude worse than the environmental cost from the same with nuclear power, at least when it comes to things like powering cities.

Solar of course is good for things like calculators, and stop lights in rural areas.


I think the important thing to think about is practicality and engineering. At this stage, nuclear fission (even with all its extra costs of overhead, safety, and so on) is so much better (for current big problems) than any solar cell technology we have that it's not even worth considering.

Also, solar power is very useful locally but not 'globally' (in the sense of not-in-the-immediate-area). In some areas, it's quite good even considering current caps on the technology. In other areas, however, it is very poor - so poor that it's not even worth the initial cost. One of the biggest reasons it's not as useful 'globally' is that we wouldn't tap all the solar energy even if we could - we would experience global cooling, if you will, and die (this is a look at the long-run, obviously).

It's good in principle to 'push' solar since that's the only way the technology will advance, but there's no point comparing it to fission. They both have separate strengths. In a game of numbers, fission will always win. You can always build a few more fission reactors, even underground if need be. So fission is more useful for backbone infrastructure and large-scale output. Solar is useful for improving total efficiency. It's difficult and impractical to build a small-scale nuclear reactor - like a generator you could tow around in a truck for example. If someone gave you a contract for all the money you could possibly need and said 'build me a new energy infrastructure' you'd be better off making a 'grid' (the setup we have today) of nuclear reactors and making local use of solar power - apartment complexes, large buildings, housing materials, and so on. That way you could meet macro-scale demand practically, and still have very good efficiency locally.

You really need both for the win. In fact, as time goes on, it looks like the energy problem is better dealt with by tossing as many different energy methods into the hat as possible.

But the immediate problem is that coal power is problematic and needs to be replaced before it gets out of hand. The answer to this is nuclear fission.
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Re: Nuclear Power, what's your issue with it?

Postby Cosmologicon » Mon May 26, 2008 5:21 pm UTC

Vaniver wrote:Nuclear fission: operational, safe, and economical for 50+ years. Solar power: semi-operational, not as safe, not economical, not aligned with demand. It might be competitive in ten-thirty years; but it's not now.

Not as safe? Care to elaborate?
Mettra wrote:Also, solar power is very useful locally but not 'globally'.... we wouldn't tap all the solar energy even if we could - we would experience global cooling, if you will, and die

No, that's not true. What do you think happens to solar energy after it's "tapped"?

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Re: Nuclear Power, what's your issue with it?

Postby Vaniver » Mon May 26, 2008 5:49 pm UTC

Cosmologicon wrote:Not as safe? Care to elaborate?
Deaths per terawatt-hour produced, but now that I look for statistics I can't seem to find many- only a poorly sourced one for home solar panels that was higher than nuclear. I most likely mixed solar and wind (I know wind is less safe than nuclear).
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Re: Nuclear Power, what's your issue with it?

Postby Mettra » Mon May 26, 2008 6:19 pm UTC

Cosmologicon wrote:
Mettra wrote:Also, solar power is very useful locally but not 'globally'.... we wouldn't tap all the solar energy even if we could - we would experience global cooling, if you will, and die

No, that's not true. What do you think happens to solar energy after it's "tapped"?


It's reintroduced back into the system, as you are implying. But if we put all the energy into moving a big metal sheet back and forth (as a silly example), the ocean currents have no reason to maintain their current patterns. We'd have to put up lamps in forested areas. The total energy is of course conserved, but the distribution is not eqivalent, and the sun does a better job of distributing the energy to the natural systems than we could at this point.

So vast swathes of the world would become much much colder than they usually are, hence the gross 'global cooling' term. Presumably all that solar energy would not be put into heaters to reheat the world, it would be converted into mechanical and electrical energy to meet the demands of humans.
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Re: Nuclear Power, what's your issue with it?

Postby zenten » Mon May 26, 2008 6:46 pm UTC

Mettra wrote:
Cosmologicon wrote:
Mettra wrote:Also, solar power is very useful locally but not 'globally'.... we wouldn't tap all the solar energy even if we could - we would experience global cooling, if you will, and die

No, that's not true. What do you think happens to solar energy after it's "tapped"?


It's reintroduced back into the system, as you are implying. But if we put all the energy into moving a big metal sheet back and forth (as a silly example), the ocean currents have no reason to maintain their current patterns. We'd have to put up lamps in forested areas. The total energy is of course conserved, but the distribution is not eqivalent, and the sun does a better job of distributing the energy to the natural systems than we could at this point.

So vast swathes of the world would become much much colder than they usually are, hence the gross 'global cooling' term. Presumably all that solar energy would not be put into heaters to reheat the world, it would be converted into mechanical and electrical energy to meet the demands of humans.


I hate it when I have people arguing on my "side" who have no idea what they're talking about.

Please read this page, and make sure to understand it before continuing this discussion: http://en.wikipedia.org/wiki/Laws_of_thermodynamics

Essentially, no, the heat doesn't end up "turning into mechanical energy" forever. The only ways you're going to get what you describe is if solar panels reflect most of the light away (more than what they would normally be shining on them) or if everyone has something silly like high efficiency lamps pointed up at the sky.

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Re: Nuclear Power, what's your issue with it?

Postby Mettra » Mon May 26, 2008 7:12 pm UTC

zenten wrote:I hate it when I have people arguing on my "side" who have no idea what they're talking about.

Please read this page, and make sure to understand it before continuing this discussion: http://en.wikipedia.org/wiki/Laws_of_thermodynamics

Essentially, no, the heat doesn't end up "turning into mechanical energy" forever. The only ways you're going to get what you describe is if solar panels reflect most of the light away (more than what they would normally be shining on them) or if everyone has something silly like high efficiency lamps pointed up at the sky.


I'm not on anyone's side.

I didn't say anything even remotely like what you're talking about. My argument had to do with distribution - how, unless we built lamps in forests and heated ocean currents (and billion other things like this), all the heat would be distributed in areas such that the thermal topology would change.

The closest thing that looks like what you claim I said is "Presumably all that solar energy would not be put into heaters to reheat the world, it would be converted into mechanical and electrical energy to meet the demands of humans." But in a rational discussion about practical matters, one is supposed to realize that humans don't live in the oceans, in Antarctica, and other areas that would be affected by the hording of energy into human-populated areas - and that's even ignoring the context of the entire remainder of my post.

Since it's apparently good form to call someone a neanderthal in this discussion, I'll pass on my own useful link for your instruction: http://en.wikipedia.org/wiki/Reading_comprehension
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Re: Nuclear Power, what's your issue with it?

Postby MotorToad » Mon May 26, 2008 7:32 pm UTC

Mettra wrote:So vast swathes of the world would become much much colder than they usually are, hence the gross 'global cooling' term. Presumably all that solar energy would not be put into heaters to reheat the world, it would be converted into mechanical and electrical energy to meet the demands of humans.
I find this... astonishing. Please equip yourself with the very basest of clues before ever posting anything as if it were a fact.

This is so... uhm... far from smart that I can't even think how to argue against this without using language that would boil down to name calling. So, all I can say is please don't throw this tripe at our eyes anymore.
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Re: Nuclear Power, what's your issue with it?

Postby zenten » Mon May 26, 2008 7:36 pm UTC

Mettra wrote:
zenten wrote:I hate it when I have people arguing on my "side" who have no idea what they're talking about.

Please read this page, and make sure to understand it before continuing this discussion: http://en.wikipedia.org/wiki/Laws_of_thermodynamics

Essentially, no, the heat doesn't end up "turning into mechanical energy" forever. The only ways you're going to get what you describe is if solar panels reflect most of the light away (more than what they would normally be shining on them) or if everyone has something silly like high efficiency lamps pointed up at the sky.


I'm not on anyone's side.

I didn't say anything even remotely like what you're talking about. My argument had to do with distribution - how, unless we built lamps in forests and heated ocean currents (and billion other things like this), all the heat would be distributed in areas such that the thermal topology would change.

The closest thing that looks like what you claim I said is "Presumably all that solar energy would not be put into heaters to reheat the world, it would be converted into mechanical and electrical energy to meet the demands of humans." But in a rational discussion about practical matters, one is supposed to realize that humans don't live in the oceans, in Antarctica, and other areas that would be affected by the hording of energy into human-populated areas - and that's even ignoring the context of the entire remainder of my post.

Since it's apparently good form to call someone a neanderthal in this discussion, I'll pass on my own useful link for your instruction: http://en.wikipedia.org/wiki/Reading_comprehension


You stated that "So vast swathes of the world would become much much colder than they usually are". That's not going to happen, baring impossible designs for solar panels (or very highly inefficient ones). Which is why I assumed you just didn't understand the laws of thermodynamics.

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Re: Nuclear Power, what's your issue with it?

Postby bigglesworth » Mon May 26, 2008 7:40 pm UTC

Mettra wrote:I'm not on anyone's side.

I didn't say anything even remotely like what you're talking about. My argument had to do with distribution - how, unless we built lamps in forests and heated ocean currents (and billion other things like this), all the heat would be distributed in areas such that the thermal topology would change.


I understand what you're saying. But since internal combustion engines (and all engines) already release lots of energy concentrated in cities already, and since the cooling effect of some heat/light being converted into electricity is so small, the effect would be negligible.

The ocean currents are already changing because of the greenhouse effect - this effect would be much smaller.
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Re: Nuclear Power, what's your issue with it?

Postby Izawwlgood » Mon May 26, 2008 8:23 pm UTC

I'm not sure the temperature released from traffic is what is responsible for increases in temperature around some cities. In fact, I'm fairly sure it's not.

Conversly, I wouldn't think that really large solar panels would have any effect on the environment they are situated in. Perhaps immediatly under them you would experience lower temperature, but a 50mile x 50mile region of solar panelling isn't going to change a desert into a marsh.
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Re: Nuclear Power, what's your issue with it?

Postby Vaniver » Mon May 26, 2008 8:27 pm UTC

Izawwlgood wrote:I'm not sure the temperature released from traffic is what is responsible for increases in temperature around some cities. In fact, I'm fairly sure it's not.
I've heard that it's a combination of the buildings trapping heat and air conditioning systems dumping heat from inside the buildings outside- I don't know if transportation is significant or not.
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Re: Nuclear Power, what's your issue with it?

Postby Izawwlgood » Mon May 26, 2008 8:42 pm UTC

I've heard it's primarily reflected thermal radiation from building windows and blacktopped pavement. In addition to restricted air flow through city streets. I've never heard anything about traffic changing the air temperature of busy cities. Perhaps in the smog effect, but surely not due to heat waste from the engines.
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Re: Nuclear Power, what's your issue with it?

Postby Mettra » Mon May 26, 2008 11:34 pm UTC

zenten wrote:You stated that "So vast swathes of the world would become much much colder than they usually are". That's not going to happen, baring impossible designs for solar panels (or very highly inefficient ones). Which is why I assumed you just didn't understand the laws of thermodynamics.


The unfortunate thing about long discussions is that the details get carried away by the tide of points, counterpoints, and so on.

The entire discussion stemmed from "...we wouldn't tap all the solar energy even if we could - we would experience global cooling, if you will, and die (this is a look at the long-run, obviously)." When I say all, I mean 100% of it. The response that I gave the "vast swathes" comment to was responding to this point. So it was assumed at this point in the discussion that 100% of the solar energy reaching Earth was somehow being captured - the thing I imagined was some huge satellite array/contraption since putting solar cells on top of the ocean seemed nonsensical. Since this was the premise of the argument, it was the regime in which I was working. In other words, the discussion wasn't about solar cell technology - the method for capturing 100% was not discussed, it was just assumed. The discussion at that point was about 'what would happen if we were to do this?'.

Now, if one were to capture 100% of the solar energy reaching the earth and then concentrate that energy into human-populated areas only, it would change the thermal topography of the landscape. The implication is that we're not clever enough to avoid negative consequences that this might have.

I tried to be very explicit in this post, so hopefully that clears up any confusion. It's slightly annoying to be quote-mined into some 'soundbite' because of loss of context.

/edit - @MotorToad: perhaps you'd care to set me straight in a PM instead of adding noise to the discussion.
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Re: Nuclear Power, what's your issue with it?

Postby tdc » Tue May 27, 2008 7:54 am UTC

I would think that not letting any sunlight through to the earth would cause bigger problems than global cooling. Namely global plant death.
This is probably why nobody took your "capture all sunlight" as "capture ALL sunlight" ;-)

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Re: Nuclear Power, what's your issue with it?

Postby zenten » Tue May 27, 2008 1:43 pm UTC

Mettra wrote:
zenten wrote:You stated that "So vast swathes of the world would become much much colder than they usually are". That's not going to happen, baring impossible designs for solar panels (or very highly inefficient ones). Which is why I assumed you just didn't understand the laws of thermodynamics.


The unfortunate thing about long discussions is that the details get carried away by the tide of points, counterpoints, and so on.

The entire discussion stemmed from "...we wouldn't tap all the solar energy even if we could - we would experience global cooling, if you will, and die (this is a look at the long-run, obviously)." When I say all, I mean 100% of it. The response that I gave the "vast swathes" comment to was responding to this point. So it was assumed at this point in the discussion that 100% of the solar energy reaching Earth was somehow being captured - the thing I imagined was some huge satellite array/contraption since putting solar cells on top of the ocean seemed nonsensical. Since this was the premise of the argument, it was the regime in which I was working. In other words, the discussion wasn't about solar cell technology - the method for capturing 100% was not discussed, it was just assumed. The discussion at that point was about 'what would happen if we were to do this?'.

Now, if one were to capture 100% of the solar energy reaching the earth and then concentrate that energy into human-populated areas only, it would change the thermal topography of the landscape. The implication is that we're not clever enough to avoid negative consequences that this might have.

I tried to be very explicit in this post, so hopefully that clears up any confusion. It's slightly annoying to be quote-mined into some 'soundbite' because of loss of context.

/edit - @MotorToad: perhaps you'd care to set me straight in a PM instead of adding noise to the discussion.


Yeah, that would be a dumb thing to do. Especially since at that point it wouldn't be much harder to just capture sunlight with collectors that aren't in orbit around the Earth.

But anyway, solar power being a viable sole means of electricity generation doesn't require what you're talking about.

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Re: Nuclear Power, what's your issue with it?

Postby Mettra » Tue May 27, 2008 2:54 pm UTC

tdc wrote:I would think that not letting any sunlight through to the earth would cause bigger problems than global cooling. Namely global plant death.
This is probably why nobody took your "capture all sunlight" as "capture ALL sunlight" ;-)


I mentioned other natural systems in previous posts, including plants needing 'lamps' if we were to do this. Global 'cooling' was just a gross catch-all term for 'all the stuff that would happen'. Unfortunately I'm not any more creative than that. I suppose I could have called it the Mettra effect or something else ;).

zenten wrote:But anyway, solar power being a viable sole means of electricity generation doesn't require what you're talking about.


I agree here, and that wasn't the point of my example. All I was saying was that there is a 'low' maximum limit with solar compared with fission. Solar scales with area, but fission scales with volume, in other words. We have an awful lot more volume (building vertically under and above-ground) than we do area.

But that's just a detail. We will eventually need both of them AND other sources of energy in order to be efficient.

My overarching argument, however, was that fission should be our target for the immediate future. Solar power generating methods don't have the capacity at this stage in our technology/engineering to replace our coal power infrastructure. When we replace the coal power (I argued that coal power was problematic and should be replaced [not just in one place, over the entire globe]), then we can look at practically applying solar and other methods to increase the overall efficiency of our new fission grid. This is really the essence of what I was saying, solar isn't ready at this stage to step up to the plate and fix our immediate big problems.
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Re: Nuclear Q&A with Industry

Postby om617 » Thu May 29, 2008 12:55 pm UTC

Nuclear power is entirely viable for land transportation, and I'm surprised that nobody has brought this up: many trains are powered directly from overhead or ground lines, which can in turn be supplied by a stationary nuclear plant. Getting this to work with cars would probably not be feasible, but it doesn't have to be. Batteries and compressed air are both proven energy-storage mechanisms for the kind of short-term operation cars require.

and now on to...

Fusion
One of the biggest issues with fusion is plasma instability- the plasma doesn't like to stay in a nice ring, although the D-shaped cross section of the torus that JET uses (and ITER will use) seems to be better than a circular cross section. The tokamak design manages plasma instability by using a helical magnetic field. Coils running around the torus produce a B field parallel to the direction of the torus, while the current running around the torus produces a B field perpendicular to the direction of the torus... the combined result is helical. The massive current also provides resistive heating of the plasma, although that doesn't bring it all the way up to the necessary temperatures (10^8 K) as the effectiveness of resistive heating drops off with the heat of the plasma, which is where RF heating and neutral beam injection comes in.

The idea that a bigger torus results in a higher Q (energy out / energy in) is well established to the point that if ITER fails to net some energy, a lot of folks will be quite surprised. The biggest hurdles towards reaching commercial power involve a couple of different kinds of material engineering. The confinement chamber needs to be able to survive high temperatures and radiation levels, and the magnetic coils need to be able to survive the stress of constant operation. ITER will also be a proving ground for remote handing mechanisms, since once it ignites, the inside will be very (radioactively) hot, even when off, due to the chamber being constantly bombarded with small energetic guys.

Hope that helps.
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Re: Nuclear Q&A with Industry

Postby Mabus_Zero » Fri May 30, 2008 6:22 am UTC

Wow...thanks, that's all very interesting.
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Re: Nuclear Q&A with Industry

Postby Minerva » Fri May 30, 2008 8:28 am UTC

Isn't JET already providing something of a testbed for remote handling of the vessel components, activation of the materials in the D-T neutron spectrum, and tritium handling?

It's a shame that there's only that one facility out of all the tokamaks in the world that is actually burning deuterium-tritium. It seems like having more tritium-equiped facilities would be expeditious for the research.
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Re: Nuclear Q&A with Industry

Postby Barthanatos » Fri May 30, 2008 2:53 pm UTC

Minerva wrote:Isn't JET already providing something of a testbed for remote handling of the vessel components, activation of the materials in the D-T neutron spectrum, and tritium handling?


news.google.com search for (JET tritium) yields this 2005 article:
http://goliath.ecnext.com/coms2/summary ... 926672_ITM

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Re: Nuclear Q&A with Industry

Postby stevenf » Fri May 30, 2008 7:47 pm UTC

Have we factored into those contributions in this thread favourable to nuclear power the negative factors associated with the construction of plant, the decommissioning of plant and the storage over geological time periods of high level waste?

The UK is, at present, seething with angst on the question and the debate is getting hot - to put it mildly. The government seems to be in favour of nuclear but we have abundant alternatives (ocean currents, wave, tides, hydro, wind etc).

My own view primarily derives from biological considerations. We simply do not know what the long term consequences are of a steady rise in background on the DNA of all living matter. We have no hope of unwinding anything adverse - ever. We are vehicles for DNA rather than anything else - best not meddle Eh?

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Re: Nuclear Q&A with Industry

Postby om617 » Fri May 30, 2008 10:06 pm UTC

(As this thread was meant as a technical Q&A rather than an argument, I will try to keep this brief and limited to fact rather than opinion.) In response to the above:

1) Nuclear power plants do generate dangerously radioactive waste with a half life on the order of hundreds to thousands of years, which must be managed. Note that this waste is managed rather than being released into the atmosphere as is the (often radioactive) waste of other forms of baseload power generation.

2) The increase in background radiation from properly stored waste is negligible. Routine dental X-rays and cosmic background radiation are greater threats to human health. The increase in background radiation from a correctly built and operated power station is similarly negligible.

3) Breeder reactors permit us to reuse the waste from current reactors and eliminate the long lived isotopes from generated waste, resulting in waste with a half life on the order of scores of years. We can build some types of these today, but as power stations they are less economical than standard PWR designs. Note that the benefit of reduction in long-lived waste is not factored into these economics.

4) There are environmental costs from ore mining, waste heat, construction of, and decommissioning of the plants. There are similar environmental costs from all forms of power generation, including renewable sources.
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Re: Nuclear Q&A with Industry

Postby Yakk » Fri May 30, 2008 10:55 pm UTC

There are a bunch of "quality" issues with power.

A> Can it reliably produce more power when people need more power? Ie, is it reliable.
B> What is it's total costs? Infrastructure and fuel over plant lifetime.
C> What are it's capacity costs? Power demand changes over a day -- having a low-capacity cost plant is useful to deal with peak demand.
D> Can you get it near the consumers? Power transmission requires infrastructure and reduces efficiency.
E> How much does it cause damage to the environment?
F> How much does it kill people?

The problem with "wave, tides, wind" is that they fail horribly on <A> -- they produce power when they feel like it. Of their costs, most of their costs are fixed -- so they fail on category C as a "spike power" producer. Their total costs are amazingly high compared to other alternatives. And for the most part, the best places to generate this power aren't where the people are always.

Wind power causes a huge amount of human casualties in terms of people killed per power produced. I don't know about the others.

"hydro". Hydro acts as a battery pretty decently. You cannot, in general, have it near consumers -- it is where it is. Total costs aren't bad, if you don't count the environmental damage from huge massive flood projects. But Hydro is limited to what nature provides -- for it to be cheap, you need a large flow of water that falls rapidly to catch and draw power out of. It is pretty reliable, barring parched conditions.

"ocean currents" I know less about.

I believe Nuclear fails on A and C, with political problems sometimes causing problems with D. Nuclear beats out environment-wise other proven power technologies and it has a ridiculously low death rate compared to the competition, due to the low volume of the raw materials required to provide Nuclear power and the ability to contain the waste products.

Feel free to correct me if I'm in error.
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