Radley Balko has Greenpeace dead to rights on their anti-nuke demogoguery.

Note to self: Think about this. Could be bad, if [FILL IN SCARY AND ALARMIST SCENARIO WHERE SHEEPLE GET IT].

So where is Greenpeace in all the handwringing over Iran's nuclear ambitions?

One thing that is a legitimate worry about the use of nuclear power is the problem of what to do with the waste.

Two points about this; the problem gets a lot easier if you allow reprocessing to use the plutonium, which is the longest-lived fraction; and the easiest way to store the rest is to glassify it, put it in a big pile in the middle of a desert, surround the pile with a chainlink fence, and put up signs at 50-foot intervals saying "IF YOU CROSS THIS FENCE YOU WILL DIE".

If anyone crosses the fence after that? Well, Darwin always wins.

Ian: no, the problem does not get a lot easier if you allow reprocessing. Reprocessing is an uneconomical way to deal with waste. It's an order of magnitude cheaper to just stick the spent fuel rods (after a few years of cooling in pools) into sealed armored dry casks. Maybe at some point we'll want to reprocess the stuff (say, after the shortlived fission products have decayed sufficiently that the Pu that remains is judged too vulnerable to diversion, which might happen after a century or so), but delaying that for decades, centuries, or longer just makes reprocessing easier and greatly reduces the present cost due to the time value of money.

BTW, you'd want to recycle not just plutonium, but also other minor actinides. Conventional thermal reactors cannot destroy the Pu or minor actinides, since after a couple of trips throught the reactors the isotope mix becomes unacceptable. So, you either have to use fast reactors (with multiple recycles, taking many decades to destroy even the actinidies that have accumulated so far) or dispose of the actinides separately without transmutation.

Dry cask storage appears to be the solution we're moving to in the US. It's simple, cheap, and safe.

I imagine the talk of "reprocessing" economically depends on what is being reprocessed. My understanding is that fuel rods can be recycled (perhaps economically), while it makes little to do anything with low level radioactive waste.

To everyone:

It appears that one of the major arguments against nuclear power is that the waste will be around twenty times longer than civilisation has endured so far. As I understand it, the main species with this property is Pu239. So why not get rid of it? It can't be that difficult to design a reactor that can use used fuel rods.

Secondly, can anyone tell me why it is impossible to use the residual energy of the high-activity products (I'm told that waste tanks need to be actively cooled to avoid them boiling!) for something? Reactor cooling fluid preheating, perhaps?

The supply of uranium, particularly U235, is severely limited. If the world, or a significant fraction of it, decided to switch to nuclear, I am told that the estimated life of economically available uranium is about 30 years. Why not use the other 93% by making plutonium out of it?

And of course plutonium inside a reactor is unavailable for nefarious purposes, and plutonium that has been burned for energy is even more so. I would like to see a story about terrorists attempting to make a nuke out of used fuel rods - rad sickness seems to me to be a suitable death for scum like that.

Incidentally, can anyone tell me about thorium breeding to U233?

My understanding is that fuel rods can be recycled (perhaps economically), while it makes little to do anything with low level radioactive waste.

I was refering to the reprocessing of spent fuel. It's quite expensive.

So why not get rid of it?

Because it's a waste of money. Society is better off if we don't.

Look at it this way. Suppose you decide you do want to get rid of it. We don't reprocess immediately, since uranium is cheap and if you wait the waste gets cooler and, besides, storing the spent fuel costs very little. So, how long do you wait? Let's say you wait a year. The next year comes around, and you have to make the same decision. It's still cheaper to wait than to reprocess it now. So you wait again. Eventually, you realize that (unless reprocessing becomes far cheaper or uranium far more expensive) it never is economically rational to reprocess the fuel. This is essentially the process the US has been going through, reaching the correct solution by creative institutional procrastination.

At some point down the road, maybe centuries hence, perhaps the ultrafuturistic technology of the day will change the calculation. Or maybe they'll decide it's cheaper to ship the fuel, casks and all, up on some of those $5/lb. spaceliners that leaves for the moon every 3 minutes from Mojave Spaceport.

Ian: Here's a good briefing paper on using thorium

http://www.uic.com.au/nip67.htm

Two notes... first, somebody (SDB?) a while back pointed out that Japan figured out how to extract uranium from seawater. At cheaper prices than reprocessing fuel rods with current technology (but not close to the cost of mining it). Sorry, no source links for that.

Now, Jon Goff posted a link to a great Thorium resource recently.

http://thoriumenergy.blog*.com/

*spot

That covers a heck of a lot of the details. It certainly got me interested in the proposition.