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 Post subject: Plutonium dispostion
PostPosted: Mar 06, 2014 9:47 am 
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Now that the Savannah River Site MOX fabrication facility is shut down, how will the US meet its treaty obligations to dispose of at least 34 tons of weapons-grade plutonium?

A DMSR can burn 86% Th-232, 11% U-238, and 5% U-235. It doesn't take much fissile to keep it going. I would suppose about 5% Pu-239 would suffice, so the 34 surplus tons could produce roughly 780 GW-years of electricity in DMSRs. That's about the same as the current US LWR fleet produces in a decade.

http://nnsa.energy.gov/aboutus/ouropera ... ementaleis
http://energy.gov/sites/prod/files/EIS- ... y-2012.pdf


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 Post subject: Re: Plutonium dispostion
PostPosted: Mar 06, 2014 12:17 pm 
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Just use an MSR without thorium in it to "burn" plutonium. Thorium and the light uranics just complicate things if burning plutonium is all you're trying to do. I'm pretty convinced that had research on MSR continued into the early 80s they would have ditched the thorium part of the DMSR concept and just gone to a straight U/Pu burner.


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 Post subject: Re: Plutonium dispostion
PostPosted: Mar 06, 2014 1:31 pm 
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robert.hargraves wrote:
Now that the Savannah River Site MOX fabrication facility is shut down, how will the US meet its treaty obligations to dispose of at least 34 tons of weapons-grade plutonium?


I wouldn't assume that in today's political climate, with the Russian army occupying the Crimean peninsula, that anyone's too wrapped around the axle about our "treaty committments" to Russia.


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 Post subject: Re: Plutonium dispostion
PostPosted: Mar 06, 2014 2:42 pm 
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Hopefully this will blow over in a year.


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 Post subject: Re: Plutonium dispostion
PostPosted: Mar 07, 2014 1:56 am 
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http://dae.nic.in/writereaddata/.pdf_38
Refer to pages on plutonium disposition and PWR.
The plutonium can be usefully employed in existing PWR's, the main lot of reactors working. Fuel design and fabrication is the only work required. 233U will be a part of spent fuel for use if and when required.


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 26, 2014 12:31 pm 
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robert.hargraves wrote:
Now that the Savannah River Site MOX fabrication facility is shut down, how will the US meet its treaty obligations to dispose of at least 34 tons of weapons-grade plutonium?

A DMSR can burn 86% Th-232, 11% U-238, and 5% U-235. It doesn't take much fissile to keep it going. I would suppose about 5% Pu-239 would suffice, so the 34 surplus tons could produce roughly 780 GW-years of electricity in DMSRs. That's about the same as the current US LWR fleet produces in a decade.

http://nnsa.energy.gov/aboutus/ouropera ... ementaleis
http://energy.gov/sites/prod/files/EIS- ... y-2012.pdf

Ironically that makes it a poor pathway for the destruction of weapons grade Pu, because you cannot burn it fast enough. Even the initial disposition of weapons grade Pu into a running reactor core, there are other designs that would soak up that initial inventory faster (more fissile/core) which provides a very active form of protection and immediately starts the process on isotopic degradation to further reduce the attractiveness of this material.

I do believe that there is a niche market there that MSR's can fill, that may be one route to commercialisation, a government contract to destroy Pu by fission. If we all took a long term view, that could be via DMSR, but more likely a non-moderated fast spectrum design like the TMSR-NM requiring a high fissile loading.


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 26, 2014 7:37 pm 
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Table 3.5 Wash-1097.
Higher amount of Pu will be required for initial feed in a Th-Pu fast reactor. The used fuel will yield U-233 by extraction with chlorine as UCl6, if and when required for LFTR. Conversion of chloride to fluoride is likely to present least problems.


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 28, 2014 7:35 am 
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robert.hargraves wrote:
Now that the Savannah River Site MOX fabrication facility is shut down, how will the US meet its treaty obligations to dispose of at least 34 tons of weapons-grade plutonium
Starter charges for 2.2+ fluid Liquid Fluoride Thorium Reactors.

_________________
DRJ : Engineer - NAVSEA : (Retired)


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 28, 2014 9:51 am 
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From a recent (April 2014) DoE report:

https://dl.dropboxusercontent.com/u/116 ... 202014.jpg


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 28, 2014 3:41 pm 
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Lindsay wrote:
robert.hargraves wrote:
Now that the Savannah River Site MOX fabrication facility is shut down, how will the US meet its treaty obligations to dispose of at least 34 tons of weapons-grade plutonium?

A DMSR can burn 86% Th-232, 11% U-238, and 5% U-235. It doesn't take much fissile to keep it going. I would suppose about 5% Pu-239 would suffice, so the 34 surplus tons could produce roughly 780 GW-years of electricity in DMSRs. That's about the same as the current US LWR fleet produces in a decade.

http://nnsa.energy.gov/aboutus/ouropera ... ementaleis
http://energy.gov/sites/prod/files/EIS- ... y-2012.pdf

Ironically that makes it a poor pathway for the destruction of weapons grade Pu, because you cannot burn it fast enough. Even the initial disposition of weapons grade Pu into a running reactor core, there are other designs that would soak up that initial inventory faster (more fissile/core) which provides a very active form of protection and immediately starts the process on isotopic degradation to further reduce the attractiveness of this material.

I do believe that there is a niche market there that MSR's can fill, that may be one route to commercialisation, a government contract to destroy Pu by fission. If we all took a long term view, that could be via DMSR, but more likely a non-moderated fast spectrum design like the TMSR-NM requiring a high fissile loading.


You can definitely load up a fast reactor with more fissile but even in a thermal reactor you have flexibility to put in more or less heavy metal. You need to keep the fissile/fertile ratio reasonably constant, watch the melting point of your salt, and watch the loading of tri-fluorides but there is a lot of flexibility. I think the DMSR is much closer to ready so I think we could load these up fast enough. Even the MOX was planned to take over 20 years.


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 29, 2014 12:05 am 
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Lars wrote:
You can definitely load up a fast reactor with more fissile but even in a thermal reactor you have flexibility to put in more or less heavy metal. You need to keep the fissile/fertile ratio reasonably constant, watch the melting point of your salt, and watch the loading of tri-fluorides but there is a lot of flexibility. I think the DMSR is much closer to ready so I think we could load these up fast enough. Even the MOX was planned to take over 20 years.
I agree, DMSR is closer and an excellent place to start. If we need to disposition more Pu, let's just build more reactors or build cores with a slightly bigger volume, there are many ways to tweak DMSR to accommodate more Pu if that's part of the mission.

I'm fascinated by how little Pu DMSR accumulates over time, which probably means that it will burn down reasonably quickly.


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 29, 2014 4:22 am 
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An Indian paper gives thorium as the best way to get maximum from various fuels
http://dae.nic.in/writereaddata/.pdf_38
It covers various types of existing reactors in different sections. DMSR could form the basis for an additional section of MSR's. The initial D has unfortunate connotations of NPT. Uranium has the advantages of better solubility in salts but thorium could be better introduced as internal and external blankets of metallic thorium. U-233 could enter solution as fluoride.


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 29, 2014 8:00 am 
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Kirk Sorensen wrote:
robert.hargraves wrote:
Now that the Savannah River Site MOX fabrication facility is shut down, how will the US meet its treaty obligations to dispose of at least 34 tons of weapons-grade plutonium?


I wouldn't assume that in today's political climate, with the Russian army occupying the Crimean peninsula, that anyone's too wrapped around the axle about our "treaty committments" to Russia.


Kirk, it's your forum, and I'm not sure why you would want to bring politics into it, but please consider this, the Russian invasion and occupation of Crimea killed ... no one (why?, isn't that worth thinking about?). Contrast that with the American invasion and occupation of Iraq, which killed at a minimum 100,000 people. Can you understand that not everyone may see the World the way you do (or the way it is portrayed on American Television)?


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 29, 2014 10:15 am 
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Whether they killed anyone is irrelevant - they have decided that might is right once again.

In which case NATO is probably going to need additional might.

34,000kg of weapons grade plutonium is rather hard to replace once its burned off - might as well keep it for now.


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 29, 2014 10:55 am 
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SteveK9 wrote:
Kirk Sorensen wrote:
robert.hargraves wrote:
Now that the Savannah River Site MOX fabrication facility is shut down, how will the US meet its treaty obligations to dispose of at least 34 tons of weapons-grade plutonium?


I wouldn't assume that in today's political climate, with the Russian army occupying the Crimean peninsula, that anyone's too wrapped around the axle about our "treaty committments" to Russia.


Kirk, it's your forum, and I'm not sure why you would want to bring politics into it, but please consider this, the Russian invasion and occupation of Crimea killed ... no one (why?, isn't that worth thinking about?). Contrast that with the American invasion and occupation of Iraq, which killed at a minimum 100,000 people. Can you understand that not everyone may see the World the way you do (or the way it is portrayed on American Television)?


Maybe not in Crimea, but plenty of collateral damage in Donetsk. If they stopped with Crimea I doubt it would be a long lasting issue, but agitating in the eastern half of Ukraine is not something that can be easily ignored.


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