Questions re: nuclear energy

[AlecBGreen]

Here in the E/E forum there seems to be a running debate on the usefulness & practicality of using more and more nuclear energy as we wean ourselves off fossil fuels. I think everyone here agrees on one point - fossil fuels are too dirty and too short-lived to be relied upon. They need to be replaced, ASAP. Here is where the discussion begins. IMO, we can transition away from fossil-fuels and toward a totally renewable global energy supply by investing in new technology and the appropriate use of existing tech. I believe wind, solar, geothermal, and some biomass combined with a focus on resource efficiency can and should replace fossil fuels. Others feel time is running too short and we shouldnt bet on renewables alone but rely on nuclear instead. Still others think we should use everything at our disposal, renewables AND nuclear. I thought I might pick the brains of my fellow DUer's:

1) What is the "best" method of generating electricity from nuclear reactions? Dont they use pebble beds now? Whats that all about?

2) Is uranium the only fuel for a nuclear power plant?

3) In general, how much does a new nuke plant cost and how long does it take to set up?

4) How much radioactive waste is produced? Is it just spent fuel rods and radioactive cooling water? Where should we put it?

5) Is fusion worth the effort or is it just a pipe dream?

6) Besides the previously mentioned sources of renewable energy (wind, solar, geo, hydro dams, wave & tidal, biomass (incl. ethanol & biodiesel) hydrogen) are there any others that I dont know about?

7) Given current trends, how long do we have until the planet turns into a total ****hole and humanity fights for its life? Im guessing 50 years. (OPINION QUESTION - feel free to spout off!)

8) Any other thoughts on the subject?

I am continually amazed by the many smart and talented people here on this forum. I hope some of you can help shed more light on this issue. PLEASE do not turn this into a name-calling mud-slinging session. I am here to learn about this issue and I know many of you are interested too. I think you might agree with me - the future of the human race depends on us finding a way to generate electricity safely, cleanly, and cheaply. Lets work to that end.

Cheers :hi:
-Alec

p.s. any good sources out there besides The Oil Drum?

[phantom power]

1. I'll take a stab...

1) I'll defer to others, such as NNadir, about "best choice," but pebble-beds do have one drawback: the fuel pellets don't lend themselves to fuel recycling, which isn't such a good thing, since fuel recycling vastly extends the amount of energy one can get out of the fuel.

I don't think there are any pebble-beds in operation, but there are some being planned. South Africa, I think.

2) Nuclear reactors can "burn" uranium or plutonium. They can also breed fuel from other elements, like thorium, or non-fuel uranium isotopes. There are probably other elements that could be used, but they aren't as common.

3) Cost seems to depend a lot on local economy, regulatory environment, etc. In the US, reactors seem to run from 4-7 billion. In France, I understand that they're cost runs more like 2 billion. India claims it will be building reactors at about 1 billion, pretty close to a "dollar/watt"

4) I'll defer to NNadir on the amount, I'm sure he has it memorized. The fuel ought to be recycled. It can also be stored on-site. There is lots of disagreement here about what should be done with spent fuel, and what risk it actually presents.

5) Fusion should be researched, but it's a completely unproven technology in the commercial sense. It has no place in any energy policy, in terms of what we should be doing today. (except for R+D funding)

6) That seems pretty complete to me.

7) We are in big trouble, and the trouble is starting now. We are entering a phase-change.

[TheWraith]

2. Not an expert, but I'll do my best to answer your questions.

1) What is the "best" method of generating electricity from nuclear reactions? Dont they use pebble beds now? Whats that all about?

A few use pebble bed designs, which are supposed to be unable to sustain a catastrophic accident due to their design. These are theoretically "best," but they're still considered experimental. Most new and existing ones are light water reactors.

2) Is uranium the only fuel for a nuclear power plant?

No, there are alternative fuel cycles. But for the majority of light-water reactors that we use, uranium is the primary choice.

3) In general, how much does a new nuke plant cost and how long does it take to set up?

That depends on a lot of things, including where you want to set up, if you're going from scratch, the capacity of the reactor, etcetera. It's cheaper and faster to add a new reactor to an existing facility than it is to build a completely new plant. However, you could safely say that numbers are in the range of 1 to 5 billion dollars, and 3.5 to 4 years to construct.

4) How much radioactive waste is produced? Is it just spent fuel rods and radioactive cooling water? Where should we put it?

Currently, it's something like 30 tons per plant, per year. We could get that done to about 1.5 tons if we reprocessed the waste to remove the still usable uranium, but this isn't currently done because it's not considered neccessary. The mass of the waste is primarily the spent fuel rods. As for storage, a deep underground site is pretty much ideal. Even if the material were to escape the packaging we put it in (unlikely), sites like the natural nuclear reactions at Oklo have shown that the fission byproducts won't move very far through the soil.

5) Is fusion worth the effort or is it just a pipe dream?

It's absolutely worth the effort. One of the leading minds in the field thinks that he and his team have developed a viable energy-positive reactor, and that they can build a 100 megawatt plant for $200 million.

6) Besides the previously mentioned sources of renewable energy (wind, solar, geo, hydro dams, wave & tidal, biomass (incl. ethanol & biodiesel) hydrogen) are there any others that I dont know about?

Not really, at least nothing that's practicable.

7) Given current trends, how long do we have until the planet turns into a total ****hole and humanity fights for its life? Im guessing 50 years. (OPINION QUESTION - feel free to spout off!)

I personally don't think it's going to happen. We humans are good at averting catastrophe.

[Kolesar]

3. (7) A global depression ala 1929 or Europe's 1945 post-colonial collapse might be a "soft landing"

A barrel can only hold a column of water as high as its rottenest stave. It is possible that peak oil could put the whole world into an unproductive funk and consumption of all resources would decline. Countries would retool to feed the people however they can. In America, the Dept of Agriculture developed guidelines for how to cook and still have nutritious meals with limited resources. Oatmeal and raisins instead of steak and imported fruit. In Europe, countries were still rationing meat and gasoline into the 1950s, IIRC.

It's possible we could still keep social order after our global economic empire dies. Rolling blackouts would surely diminish electricity demand.

[AlecBGreen]

4. this is a great point

something Ive never considered:

"It is possible that peak oil could put the whole world into an unproductive funk and consumption of all resources would decline"

[intaglio]

5. Except ...

Previous answers are pretty complete except for number (4) How much radioactive waste is produced? Is it just spent fuel rods and radioactive cooling water? Where should we put it?

There is a big problem with reactors, in that their lifetime is about 30 years and after that they should be dismantled. In practise most reactors function pretty well for another 10 to 15 years then they are shut down and should be dismantled. This involves BIG bucks. Everything in the containment building and everything in contact with the primary coolant is radioactive to a greater or lesser extent. Much is low or medium level radioactivity and and can be buried. The low level waste will be in fairly cheap unguarded sites the medium in long term secure sites. All of what remains is highly radioactive and needs to be stored, monitored, guarded and eventually buried. All of these materials are a total loss they cannot be recycled and used again. The site of the reactor has to be scraped clean and even then the site will be lost for further development for the forseeable future.

Of course the costing always avoids accidents to functioning reactors. Consider: the worst possible accident to a conventional power station would affect, at most, 100,000 people; the accident at Chernobyl (which was not the worst possible accident) affected the entire Northern hemisphere - there are still Cumbrian and Welsh farmers who cannot sell their animals because of radioactivity.

[bananas]

6. A lot of your questions are answered right here:

"Everything you could possibly want to know about nuclear power — and its (limited) potential as a potential climate solution — can be found in the new Keystone Center Report with the less-than-captivating title “Nuclear Power Joint Fact-Finding.”"
<snip>
"As the Keystone report makes clear — and as former Vice President Al Gore told Congress earlier this year — nuclear may be a part of the solution, but probably only a very limited part."
http://climateprogress.org/2007/06/18/nuclear-power-no-climate-cure-all