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

[peter fels]

Thanks Todd...encouraging...



On Mar 21, 2011, at 6:43 PM, Todd Rich wrote:

> 
> 
> 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.
> 
> 
> 
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