Energy From Thorium Discussion Forum

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PostPosted: Nov 24, 2014 12:49 am 
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KitemanSA wrote:
Removing cesium is quite simple. Plant industrial hemp or mustard. Both do a good job of bioaccumulating cesium. Harvest and anaerobically digest to reduce the contaminated volume/mass substantially. If they had started that around Chernobyl, the places treated would be effectively cesium free by now (actually 10 to 15 years ago).


That sounds expensive. Is there a market for the metals that can make up for the expense?

I'm reminded of an old metal refinery, I think they refined nickel, that was so dirty that after the refinery was rebuilt they would mine the land downwind for the metal that used to go up the smokestack. Sounds like a similar issue here, we have a valuable heavy metal that was spread far and wide. Rather than picking it up at great cost and dumping it in a hole, they mined it to be sold as a product.

This could make for a reasonable means to cleanup after a dirty bomb or nuclear power plant melt down. The government could, instead of pay people to pick it up, they could sell rights to collect it for market.

I'll also give another note on the safety of Pu-238, it was used to power implanted pacemakers. People had plutonium battery pack implanted surgically into their bodies. The only thing that I found to explain the discontinuation of the practice was the cost of the plutonium.

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PostPosted: Nov 24, 2014 9:13 am 
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Industrial hemp and mustard are rather cheap to raise really.
Especially as you don't care enough about yields to really put in any fertilisers - just plant and run a combine over it every year.


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PostPosted: Nov 25, 2014 1:15 pm 
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E Ireland wrote:
Industrial hemp and mustard are rather cheap to raise really.
Especially as you don't care enough about yields to really put in any fertilisers - just plant and run a combine over it every year.


As someone that grew up on a farm I can say that planting and harvesting are not "cheap". Assuming we can do away with fertilizers, pesticides, and herbicides the field that you want to plant still must be suitable for the equipment used to plant and harvest. That means it must be level enough that your tractor can get up and down the field without getting stuck or rolling over. Drainage must be that the tractors don't get stuck in the mud. Rocks, trees, and other obstacles need to be cleared so that the equipment is not damaged.

Running a combine is skilled labor, and the equipment is very expensive, meaning hiring someone to combine that crop is going to cost a lot of money. Just the fuel to run the equipment is a lot of money. I'm sure that planting a crop that preferentially draws in the element of concern is cheaper than a lot of other processes that could be used but I'm also sure that leaving it alone is the cheapest. Without some valuable product coming from the harvest I'm not sure that would be wiser than just leaving the area and waiting out the decay.

We might be getting off topic here but I'd think that if we are going to have an industry creating these elements that we should discuss the cleanup if there is a spill. For something like Pu-238 that can cost $1000/gram there's all kinds of ways to pick it up that might be economically feasible. For some other isotopes it may make more sense to just wait it out. That might mean declaring an area off limits for a century or four but it'd be cheaper and safer than trying to pick it all back up.

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PostPosted: Nov 25, 2014 10:28 pm 
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Location: Portland Oregon
I would like to make a comment about using an RTG for starting something like a car. RTG’s produce a study output of power, like the 110W RTG’s that NASA uses. But it does not do peak power draws well. A car starter can draw over 400 amps (4800W @ 12V). You could use the RTG to charge a battery, but you will still need the battery for the Peak power draw. Very large capacitors could also be used, if that technology improves enough.

I am not really proposing using RTGs in cars, but make this comment as an example of some of the limitations of RTGs. If there is a system that has a peak loads at times, combining RTGs and batteries could be a good combo.


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PostPosted: Nov 26, 2014 10:33 pm 
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www.youtube.com/watch?v=z3x_kYq3mHM&spfreload=10


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PostPosted: Dec 07, 2014 2:29 am 
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Kurt Sellner wrote:
KitemanSA wrote:
Removing cesium is quite simple. Plant industrial hemp or mustard. Both do a good job of bioaccumulating cesium. Harvest and anaerobically digest to reduce the contaminated volume/mass substantially. If they had started that around Chernobyl, the places treated would be effectively cesium free by now (actually 10 to 15 years ago).


That sounds expensive. Is there a market for the metals that can make up for the expense?

The idea isn't to harvest the metal, it is to remove it from the fields in a short enough time to make it feasible to expect to be planting and harvesting food within a reasonable portion of ones life span. And without removing the topsoil like current processing does. What is scaleable from the process is the bio-methane. No, it probably wouldn't earn enough to pay the cost, but it would stretch the remediation funding and make it less onerous.

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PostPosted: Dec 09, 2014 2:13 am 
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KitemanSA wrote:
Kurt Sellner wrote:
KitemanSA wrote:
Removing cesium is quite simple. Plant industrial hemp or mustard. Both do a good job of bioaccumulating cesium. Harvest and anaerobically digest to reduce the contaminated volume/mass substantially. If they had started that around Chernobyl, the places treated would be effectively cesium free by now (actually 10 to 15 years ago).


That sounds expensive. Is there a market for the metals that can make up for the expense?

The idea isn't to harvest the metal, it is to remove it from the fields in a short enough time to make it feasible to expect to be planting and harvesting food within a reasonable portion of ones life span. And without removing the topsoil like current processing does. What is scaleable from the process is the bio-methane. No, it probably wouldn't earn enough to pay the cost, but it would stretch the remediation funding and make it less onerous.


With modern agriculture I doubt that there is such a shortage of cropland that we would need to worry about clearing land of radioisotopes from a nuclear disaster. I do see a potential of using these means to harvest the valuable radioisotopes though.

Has anyone done a study of how long one would have to plant and harvest a bioaccumulating crop to remove dangerous radioisotopes from cropland? It's not like these crops will suck them all up at once, this bioaccumulation process with have a half-life of it's own. We'd have to compare the bioaccumulation half-life with the radioactive half-life of the isotopes. Of course the two processes would combine to reduce the radioactivity of the soil but if the bioaccumulation process is not fast enough then it does little to shift the equation in its favor.

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PostPosted: Dec 09, 2014 10:19 am 
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Kurt Sellner wrote:
With modern agriculture I doubt that there is such a shortage of cropland that we would need to worry about clearing land of radioisotopes from a nuclear disaster.

Tell that to Japan. In Japan you are taking culture, not reason.

Quote:
I do see a potential of using these means to harvest the valuable radioisotopes though.

Has anyone done a study of how long one would have to plant and harvest a bioaccumulating crop to remove dangerous radioisotopes from cropland? It's not like these crops will suck them all up at once, this bioaccumulation process with have a half-life of it's own. We'd have to compare the bioaccumulation half-life with the radioactive half-life of the isotopes. Of course the two processes would combine to reduce the radioactivity of the soil but if the bioaccumulation process is not fast enough then it does little to shift the equation in its favor.
I once read, but can no longer find, an article that seemed to say that cesium could be fully removed from the soil in 15 years with bio-accumulation where it would take 300 years without.

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PostPosted: Dec 09, 2014 10:32 pm 
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Paul Stamets has done studies on bi remediation of different pollution streams using mushrooms.

Here is one URL discussing it. although I am sure he has not studied the time it would take....

http://www.permaculture.co.uk/articles/ ... -fukushima


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