Energy From Thorium Discussion Forum

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PostPosted: Dec 06, 2012 9:48 pm 
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If I recall correctly the DMSR is not as thermal as an LWR, so it takes a higher fissile/fertile ratio to become critical. After burning a bit of SNF/Pu in a thermal spectrum the fuel quality of the Pu degrades to the point that the plutonium portion of the reactor is less than break even.
Most certainly you could not take SNF and remove the poisons then add 3x as much Th and have a critical reactor unless it was a CANDU.


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PostPosted: Dec 07, 2012 5:59 am 
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Lars wrote:
If I recall correctly the DMSR is not as thermal as an LWR, so it takes a higher fissile/fertile ratio to become critical. After burning a bit of SNF/Pu in a thermal spectrum the fuel quality of the Pu degrades to the point that the plutonium portion of the reactor is less than break even.
Most certainly you could not take SNF and remove the poisons then add 3x as much Th and have a critical reactor unless it was a CANDU.


What if we fluorinate the spent oxide fuel, removing the low enriched uranium and other volatiles, and just use the fluorinator bottoms as startup fuel for the DMSR?

The lanthanides will come along, but there should be plenty reactivity left in the TRUs. It could also be sold as proliferation protection (having fission products to protect the fissiles). Then we could add some of the low enriched uranium, just enough to dilute the U233 to LEU during the first month or so (maybe a few hundred kg).

Kirk talked about adding Th-230 in the fuel. This greatly increases the production of U232, so you could get to the 2.4% level with a minor addition of Th-230 in the thorium. Th-230 can be coproduced in uranium mines (equilibrium grows in to about 17 ppm Th-230 in the uranium). This could be a good way to denature the U233.

http://energyfromthorium.com/2006/10/06 ... th-ionium/


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PostPosted: Dec 07, 2012 2:05 pm 
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Cyril R wrote:
Lars wrote:
If I recall correctly the DMSR is not as thermal as an LWR, so it takes a higher fissile/fertile ratio to become critical. After burning a bit of SNF/Pu in a thermal spectrum the fuel quality of the Pu degrades to the point that the plutonium portion of the reactor is less than break even.
Most certainly you could not take SNF and remove the poisons then add 3x as much Th and have a critical reactor unless it was a CANDU.


What if we fluorinate the spent oxide fuel, removing the low enriched uranium and other volatiles, and just use the fluorinator bottoms as startup fuel for the DMSR?

The lanthanides will come along, but there should be plenty reactivity left in the TRUs. It could also be sold as proliferation protection (having fission products to protect the fissiles). Then we could add some of the low enriched uranium, just enough to dilute the U233 to LEU during the first month or so (maybe a few hundred kg).

If you retain all the salt-seeking, non-volatile fission products you will have about as much mass of fission products as of plutonium (assuming you also remove the Zr and Cs). Assuming you start with 2 tonnes Pu/GWe then you are starting with a fission product load equivalent to 7 years full operation. This seems like a pretty severe handicap. I would guess if you are reprocessing spent fuel you are at a secure central facility that has jumped through the various regulatory hoops and has survived the anti-prolif crowds attacks. If they have done that then I think the technical job of separating the Pu from the majority of fission products is comparatively easy. One could do a "poor" job and retain 1% of the fission products to provide for the self-protection. This would especially be true if we are sure to include some fresh stuff with every batch.
Quote:
Kirk talked about adding Th-230 in the fuel. This greatly increases the production of U232, so you could get to the 2.4% level with a minor addition of Th-230 in the thorium. Th-230 can be coproduced in uranium mines (equilibrium grows in to about 17 ppm Th-230 in the uranium). This could be a good way to denature the U233. http://energyfromthorium.com/2006/10/06 ... th-ionium/

If this is being added to the fuel we may be fine. We do lose 2 neutrons to converting the Th-230 to U233. It would take a bit of analysis to see how the u232/u233 ratio evolves over time properly, how much Th-230 we need to have at the beginning, whether we need to periodically add more (easy) or wish we could remove some (not possible).


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PostPosted: Dec 07, 2012 9:30 pm 
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I think once you've made LFTRs more proliferation resistant than uranium enrichment or plutonium production, you're done. (And they are pretty much at that spot from the get-go) Trying to cripple LFTRs by denaturing (during normal operation) or some other scheme is a fool's errand, and most of the time on here we play right along by thinking up progressively more absurd schemes which result in a weapons diversion. Sometimes you guys remind me of an episode of the Big Bang Theory, where a simple task becomes progressively more complex.

The anti-nuclear forces don't want anything reasonable. They want complete abandonment of nuclear power. If that costs the Western standard of living and billions of lives, that's not big deal for them. They hate humanity anyway.

Future generations will bless us if we stand our ground against them.


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PostPosted: Dec 07, 2012 9:54 pm 
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I agree with Kirk entirely. Time to stand our ground. Logic has to prevail eventually. War clubs made of wood can kill so maybe we should have banned wood and never started fires for cooking and warmth. We do have a persistent problem however. What are we to do when Sec. Chu in congressional testimony brings up proliferation as an argument against LFTRs? At some point we must insist on brutal and honest evaluation of risks and rewards associated with all choices for energy. I've termed the illogical anti-anything crowd as being cruel to humanity. I do not think that is too strong.


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PostPosted: Dec 07, 2012 11:34 pm 
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"We're the US Marines! We're here to rescue you!"

No truer words ever spoken. Let DOD side-step the regs, help get a prototype out the door, and prove the science. I can't think of a better example of where to deliver a LFTR to prove proliferation reistance than a forward base.

Beat that with a stick.

P.S. There are old stories of soldiers sending whole Jeeps home in boxes of parts...I wonder...nah better not bring that up.


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PostPosted: Dec 08, 2012 12:11 am 
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War clubs of wood is a more colorful example but the fire is a closer comparison. If you exclude the war use of either, more people die every year in fires and fuel collection than ever died in pursuit of nuclear power. Still, you cannot have a kitchen worth the name without fire. Nor can we afford to ban fire. We proceeded from wooden fires to coal, oil and gas till we are looking at peak of fossil fuels. Light and heavy water moderated reactors were the one major step in nuclear energy. Misuse of nuclear power as weapons was unfortunately the first development of nuclear energy. Limiting it to first few developers of weapons and coming in the way of other more legitimate uses is unfair and immoral. By all means think of its misuse as an important consideration but do not let it hinder the progress.
I have no difference of opinion with those who want to forego it for their own safety. Many people do not want jobs involving the use of fire. Let the Japanese and some of the Europeans try to do without nuclear energy. They may change their minds later or depend on 'Nuclear' neighbors. Proliferation avoidance can be a positive factor like safety but not a restricting one.


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PostPosted: Jan 04, 2013 3:01 pm 
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Kirk Sorensen wrote:
I think once you've made LFTRs more proliferation resistant than uranium enrichment or plutonium production, you're done. (And they are pretty much at that spot from the get-go) Trying to cripple LFTRs by denaturing (during normal operation) or some other scheme is a fool's errand, and most of the time on here we play right along by thinking up progressively more absurd schemes which result in a weapons diversion. Sometimes you guys remind me of an episode of the Big Bang Theory, where a simple task becomes progressively more complex.

The anti-nuclear forces don't want anything reasonable. They want complete abandonment of nuclear power. If that costs the Western standard of living and billions of lives, that's not big deal for them. They hate humanity anyway.

Future generations will bless us if we stand our ground against them.


I think they draw on fears still left over from the Cold War when we feared instant annihilation.

With all the issues we face today around energy security and the closely associated economic stability, if we don't seriously start making changes today then the coming chaos will probably making any earlier collapses of this sort look pathetic.

We've got a small and closing window to bring this kind of technology online, future generations will probably damn those who stood in the way of things like LFTRs if they don't stop using clearly distorted arguments to stop it's development.


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PostPosted: Jan 05, 2013 5:01 pm 
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This seems like a clear response to the question by Drs. Hargraves and Moir;

Thorium non-proliferation characteristics.

Quote:
A commercial reactor will make just enough uranium to sustain power generation. Diverting any would stop the reactor, alerting authorities to a breach. Certainly terrorists could not steal U-233 dissolved in a molten salt solution along with lethally radioactive fission products inside a sealed reactor. International Atomic Energy Agency (IAEA) safeguards would require security, accounting of all nuclear materials, surveillance and intrusive inspections. It is conceivable that a nation or revolutionary group might expel IAEA observers, stop a liquid-fluoride thorium reactor (LFTR) and attempt to remove U-233....


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PostPosted: Jan 06, 2013 7:19 am 
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And the statement by Drs H&M is why the FLiBe Energy design concept for foreign deployment has a U238 denaturing dump tank at the ready.

Personally, I kind of like the additional option of having the operators be folks who don't come from the countries where the reactor they operate exist. That should limit the chance of collusion somewhat.

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PostPosted: Jan 06, 2013 12:05 pm 
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KitemanSA wrote:
And the statement by Drs H&M is why the FLiBe Energy design concept for foreign deployment has a U238 denaturing dump tank at the ready.


What prevents the foreign country to remove the U238 from the dump tank? Nothing. The onsite manipulators, cutters, etc. can just be used to remove the U238.


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PostPosted: Jan 06, 2013 5:23 pm 
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But first they have to take the plant over, giving time for the operators to denature the fuel.

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PostPosted: Jan 07, 2013 12:33 am 
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Per Wikipedia:
Quote:
Around 99.284% of natural uranium is uranium-238, which has a half-life of 1.41×1017 seconds (4.468×109 years, or 4.468 billion years).
There are easier ways to get U238...with little more than a shovel.


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PostPosted: Jan 07, 2013 2:44 am 
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Cyril R wrote:
KitemanSA wrote:
And the statement by Drs H&M is why the FLiBe Energy design concept for foreign deployment has a U238 denaturing dump tank at the ready.


What prevents the foreign country to remove the U238 from the dump tank? Nothing. The onsite manipulators, cutters, etc. can just be used to remove the U238.

Which is why Kirk advocates not selling reactors but rather selling the electricity only.


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PostPosted: Jan 14, 2013 1:11 am 
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Nuclear power is safer than other ways of producing electricity, having resulted in less deaths than other ways for producing same amount of mega watt years.
http://nextbigfuture.com/2012/06/deaths ... .html#more
Weapons are not made from products of commercial nuclear power plants but only those designed or operated for weapon use.
LFTR's are expected to be just like other nuclear reactors, no more and no less as a class. The main (but doubtful) advantage lies in possibility of thermal breeders and related advantages which are shared with fast spectrum reactors burning uranium. They also share the benefits of other MSR's. The rest is no more than a sales talk.
It may be best to refrain from making additional claims.


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