You miss the point. The energy the U produces in a power station is not the same as the energy it produced through natural decay. In nature it does not get neutrons fired at it to blast it’s atoms apart.
I think the information presented in other posts has answered my question. With a half-life of 700 million years, very little of the total energy in the U-235 is used up in the generating process.
OK. We won’t grind the waste up and scatter it around. You can sleep comforably unless you are near a nuclear waste disposal site and are counting on no accidents of any kind for the next few thousand years. Or you don’t happen to be near an aquifer that the designers of the storage site mis guessed on.
In any case, it would seem that we are going to be forced to nuclear energy because of the unreliability of the world oil supply, considering where it is.
And we had better get started because it looks like we’re going to need some energy to produce hydrogen to run our transportation system before too long.
Not sure what you mean by that. In nature, uranium decays very gently, the atoms do not get totally blown to bits. It just isnt the same thing, natural decay is different, much less energy is released, and it’s nothing to do with the half life, it just doesnt produce the same level of energy.
This is incorrect. The process in a nuclear power plant is exactly the same as “natural” radioactive decay. It’s just that a nuclear plant creates a self-sustaining reaction. Decay is not “splitting the atom” as it used to be called. A plant concentrates the power of the decay, but does not blow the atoms to bits in any way.
Hmm, I thought it was different, because the U-235 is hit by a neutron and broken, as opposed to decaying naturally? You dont get the same products, do you?
In fact it appear I am correct: http://en.wikipedia.org/wiki/Nuclear_fission
Your appology is accepted.
You’re looking at the wrong Wikipedia page. Try Nuclear Pile
That’s what I was referring to. I agree I should have phrased it better.
Interesting, I see what you meant now! 
Actually you have to be lying that you meant that, read what you said again. And in any case, the products of that natural fission reactor would have been similar to a nuclear reactor, not natural decay.
As I understand it the fuel rods in a reactor build up the products of fission and must be replaced after about 5 years of use. With a half-life of 700 million years, very little of the available energy in the rod has been used during that 5 years. It would seem that most of the original energy remains in the U-235 that is left in the rod when it is removed. Some of the energy lost has gone into heating water and some into highly radioactive waste products.
The half-life of uranium has no bearing on how much energy remains in the fuel. The uranium in the reactor is “burned up” by fission when the reactor is operating, it does not just decay away.
Well, now I’m confused. I thought I vaguely undstood this but it seems I don’t.
The uranium is an unstable atom. When it emits a particle it changes to something else and some of the available energy of the uranium atom has left with the particle. Or hasn’t it?
After 700 million years half the atoms have emitted particles. And that doesn’t mean that half of the total available energy in the uranium is gone?
So what is the Straight Dope on this?
No, that only means half the uranium is gone. Very little energy is released when it decays naturally. The energy that is released in a reactor comes from a uranium atom absorbing a neutron, then splitting into (usually) two large pieces which are called fission products, and a couple of free neutrons. The neutrons go on to cause more fissions (a chain reaction). The fission products are themselves elements, and are usually highly radioactive.
Well sure, but doesn’t the energy that heats the water ultimately come from the uranium?
Yes, but not from its radioactive decay. It comes from the mass difference between the uranium atom and its fission products.
As I was watching my taped golf tournament the light switched on. The half-life is for natural radiation. In the reactor the fission is a result of absorbing neutrons, and this is not related to the natural radiation.
You got it 
With regards the thread topic, nuclear power contributing to global warming, a few in the press have mentioned that the process of taking uranium from the Earth and refining it gives off enough in green house gases to offset the lack thereof from the power plant. No figures have ever been given however.
Anything that causes heat on earth, by very definition does contribute to global warming, at least initially, even if the amount of heat is very small, it still is there.
Now add that a nuke power plant usually has cooling towers which turn water into humidity which goes into the air, and water is a greenhouse gas, it would tend to increase the amount of sunlight captured also, further increasing the global warming. Unless that water causes reflective clouds and causes the sunlight to be reflected back into space.
Compaired to a fossil fuel plant it woudl seem to be much better however.
The actual mining would be insignificant. Refining and enrichment does use a significant amount of electricity, but certainly much less than will result from the fuel. If the electricity used for refining and enrichment was all generated by nuclear power there would be very little CO2 released in the fuel cycle.
Even if it was all coal generated, to say the emissions were the same would mean there was no net energy created by the mined fuel, i.e. that as much fossil fuel was burned in creating the fuel as the fuel will ultimately create. This does not make sense.