[TheForge] nuke plants and other thoughts OT: POL:

[Todd Rich]

On Mon, 21 Mar 2011, Gladish, Andy wrote:

> Heard an interesting talk about radiation levels in coal plant waste.
> Apparently it's something we should be aware of- not as acute as with
> reactor waste of course, but far from benign.
> I always think of nuke by products as being in a class by themselves, but I
> think it makes more sense to think of them as one end of a bell curve.
> A.G.

http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html

>Based on the predicted combustion of 2516 million tons of coal in the 
>United States and 12,580 million tons worldwide during the year 2040, 
>cumulative releases for the 100 years of coal combustion following 1937 
>are predicted to be:
>
>U.S. release (from combustion of 111,716 million tons):
>Uranium: 145,230 tons (containing 1031 tons of uranium-235)
>
>Thorium: 357,491 tons
>
>Worldwide release (from combustion of 637,409 million tons):
>
>Uranium: 828,632 tons (containing 5883 tons of uranium-235)
>
>Thorium: 2,039,709 tons

Also, to get a perspective on amounts of radioactive exposure, here is a 
nice visual chart:

http://xkcd.com/radiation

And Pete?  Radioactive isotopes activity is inversely proportional to its 
longevity.  Yes U-285 will have a half life of 700 million years, but it's 
specific activity is so low it isn't an issue.

Take a look here: http://www.ead.anl.gov/pub/doc/uranium.pdf  The 
speicific activity is 0.0000022 curies/gram.

N-16 is an isotope that is produced in the water of light water reactors. 
A neutron replaces a proton in O-16.  That was most of the radioactivity 
that was coming out as steam in the first stage of the reactor problems. 
It has a half-life of 7.1 seconds.  It's specific ativity is better than a 
billion curies/gram.  But it is entirely gone in 10 minutes.  If you are 
right on top of this steam, and breathing it in, you have a problem, but 
short of that it isn't an issue.

The danger comes from the mid-range half-life isotopes.  Strontium-90, 
Cobalt-60, and several others.  But they hang around from a few years to 
at most a couple of centuries.

If we were allowed to reprocess nuclear fuel, these more dangerous 
isotopes could be extracted and stored.  Taking a lot less space up that 
currently happens with unprocessed nuclear fuel.  About 3 percent of the 
fuel gets used up in a nuclear fuel rod before it isn't practical to use 
it anymore.  If we could process out the actual waste, we could keep using 
the rest, and the waste only has to be store for a few lifetimes, not 
hundreds.

On top of that, there are acclerator assisted designs for thorium fuel 
cycle reactors that only fission when a particle accelerator is turned on 
to the pile.  It also has the added benefit of being able to burn up these 
nasty medium half-life waste istotopes as fuel.  At the end of a 200 year 
fuel cycle, your nuclear pile is a large chunk of lead.

Another nice thing about the acclerator assisted thorium cycle is that you 
don't wind up with any appreiciable amount of fissile materal that can be 
used to make nuclear weapons.