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PostPosted: Jan 25, 2017 8:53 am 
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I found this article: https://articles.thmsr.nl/the-flibe-energy-lftr49-the-triple-ace-in-nuclear-gen-iv-design-ea9bffcd71dd#.szx2vbyv0 which is apparently a few weeks old but I have not seen anyone else post a link.

The reactor names LFTR23 and LFTR49 appeal to me, since I read Kirk's doctoral dissertation and understand the references, but I'm not sure about the marketing appeal it may have. But as an engineer I'll say marketing is not my strong suit....

I do think the prospects of eliminating Pu stocks and/or TRUs from SNF *while* creating U233 that can be fuel or a medical isotope source...should be really compelling.

Jim L.


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PostPosted: May 03, 2017 3:58 pm 
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I agree with you Jim. And the logical place to build a LFTR-49/23 installation would be SRS!
Kirk Sorensen wrote:
Building LFTRs on the thorium fuel cycle and retiring enrichment facilities and burning down plutonium, now that would be an improvement on the state of things . . .
From: http://energyfromthorium.com/forum/viewtopic.php?f=51&p=63790#p63790

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PostPosted: May 05, 2017 11:31 pm 
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Thanks to Jim L. for posting this and to Tim Meyer for giving it a bump. I missed this the first time around and the bump allowed me to give it a look. After reading the article I have some things to ponder, allow me to share my thoughts as I "think out loud" and comment if you like.

First thing was the name...
Jim L. wrote:
The reactor names LFTR23 and LFTR49 appeal to me, since I read Kirk's doctoral dissertation and understand the references, but I'm not sure about the marketing appeal it may have. But as an engineer I'll say marketing is not my strong suit....


The article mentioned that this reactor was called "LFLEUR" at one time without spelling out where the acronym came from, assuming it is an acronym. I did a Google search on this and found out that this is French for "the flower" and the name of a perfume. This seems like a good enough reason to pick a different name but I'm curious what the acronym means/meant. I'm not the marketing type either and LFLEUR is a mouthful which is also a good reason to pick a different name.

The name does need some explanation beyond just spelling out what the letters stand for since the "element 49" nomenclature for Pu-239 is certainly not common knowledge. I do recall Mr. Sorensen walking the audience through the psychology of picking the LFTR name for his design and it seems to have worked well so far. I'm at a loss of thinking of a "better" name. It burns plutonium, breeds thorium, is a kind of molten salt reactor... I got nothin'... I think WAMSR was a good name that Transatomic came up for their reactor that shares a lot in spirit, but not necessarily in function, with LFTR49 but that name is obviously taken.

I'm with Jim L. on this, it's an appealing name but... Nope, still can't come up with a better name.

Jim L. wrote:
I do think the prospects of eliminating Pu stocks and/or TRUs from SNF *while* creating U233 that can be fuel or a medical isotope source...should be really compelling.


I see the production of U-233 as compelling as well but when I read that article I thought the mention of keeping the uranium from the reactor was hand waved over too quickly. I realize I'm not the audience for this kind of article and it certainly made a good case to keep the U-238 out but I had to think about variations on this theme.

What I see is that the thorium is added and U-233 extracted for the purpose of producing seed fuel for LFTR23, it can do this because the plutonium is sufficiently neutron rich that this extraction of neutrons would not upset the neutron balance. Could these neutrons be soaked up by something other than thorium? If there was no thorium added then that kind of kills the LFTR49 name but that's not where my thoughts took me, at least not originally.

I thought through the idea of adding some of the uranium extracted from the original spent fuel. I know that was gone through in the article but if plutonium is good for starting up these LFTR49 reactors then would not a design that can make more Pu-239 from U-238 be good too? After thinking about it some more I can see another reason why this should not be done besides the points made in the article. I see a possibility of the addition of U-238 could be a means to produce weapons grade plutonium from this reactor. I'll have to think this through some more but it seems at least plausible on first look.

When I see a new reactor design one exercise I like to go through is put on my "black hat" and think about ways I could use this as a way to make weapons. I do this because I know some anti-nuke type is going to do the same thing and I'd like to see if I can argue on how weapon proliferation fears are unfounded, or think of ways I might change the reactor to address those fears.

So far the best I can come up with is a "batch" process to produce weapon grade plutonium, much like what was done with solid fuel reactors long ago. This would be obvious to any observers that it was done, since it would severely affect it's ability to produce power. Attempts to create a continuous process would require non-trivial and obvious changes to the chemical processing.

I also thought of other means of exploiting those neutrons. What if we wanted to optimize the process for waste destruction? Some radioactive waste is long lived enough that only neutron bombardment will satisfy some people. This also brings me back to my thoughts of the similarities with Transatomic WAMSR. The original WAMSR was supposed to be able to be sufficiently neutron efficient to burn the U-238 in the spent nuclear fuel. Transatomic had to walk back their claims once people started to do their own analysis of their design. As I recall, and I could be mistaken on the details, that WAMSR would be able to not only burn the U-238 but also destroy many fission products by neutron bombardment.

If there is no U-238 in the way, like in LFTR49, and no thorium either then there could be a lot of neutrons to destroy "a lot" of fission products. How much is "a lot"? I didn't do the math. Perhaps a reactor like this could be used to bombard some other material to produce a valuable isotope. What kind of isotopes? I'm not sure, perhaps lithium-7? Tritium?

What ever this element you'd want to bombard with this reactor (that is not called a LFTR since we're not bombarding thorium) it would have to be something compatible with the salt and containment. Lithium is compatible I'd think. Perhaps not so much with the hydrogen.

That's about all my thoughts on this so far. Thanks to those that read this to the end. And I still have nothing "better" than LFTR49 for a name.

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PostPosted: May 06, 2017 7:07 am 
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Hello Kurt Sellner! Long time. So, I can't resist reacting to your latest post here. I'm hardly a nuclear engineer (either) and I love your "thinking out loud" for it's honesty. I love your marketing analysis of "LFLEUR"—fascinating! (Liquid/lithium fluoride low-enriched uranium reactor?)

Jim says Kirk published a PhD dissertation, and if so, I want a copy. I know his master's thesis from UT-Knoxville and EVERYBODY should read it, IMHO: Thorium Research in the Manhattan Project Era from May 2014. Excellent! I'd be embarrassed if I missed the explanation as to how they came up with "49" as code for 239—"23" seems obvious enough, and I hope people will forgive my brain dysfunction (it's a medical condition).

Young Albert Einstein I've heard would daydream about traveling with light or having light's point of view—a strange idea. Albert earned his exemption. You, sir, are riding with the precious highly-restricted neutrons—of WAY more "concern" compared to photons, would you say?

Isn't it always necessary in this vital concern of energy technology policy to bear in mind the neutrons' energy regime? Seems this whole mess goes back to having to decide fast versus thermal when both were not allowed—only one, and the decision was fast.

I have to wince a little to read you, though. It is so very easy to write an opinion from a distance without any real-time pressure in the midst of having the heavy responsibilities for the decisions.

Dr. Darryl Siemer has weighed in on fission products: Darryl Siemer - Vitrification of Sustainable Nuclear Fuel Cycle Radwastes and the title should be amended to read "MSR Radwastes" in my opinion humble or otherwise.

Though my chemistry is a lifetime ago and Dr. Seimer is a real nuclear chemist like Glenn Seaborg, I envision like the crazy Einstein fellow—speaking of a hot fluid phase mixture of fission products—that the system ought to be amendable to fractionation and partitioning as in liquid chromatography only where the mobile phase is FLiBe. I bet Dr. Darryl would say, "Sure if you have a huge budget." (Did we settle on the dollar value of a gram of neutrons?)

I'm pretty sure neutrons are WAY too precious for anything other than burning Pu-239 in a way to produce U-233 for the LFTR-23; where Kirk said in the subject report, one LFTR-49 for three LFTR-23s—impressive! But the goal is to get AWAY from U-238 (U-235) and move away from the higher actinides. I thought that was one of the great benefits of thorium! This is the "Energy from Thorium" Thorium Energy Alliance is it not? Thorium is about three times more abundant than uranium. That speaks for itself.

I'm a little concerned about placing a lot of eggs in the targeted alpha therapy basket. I bet there are other and more vital medical isotopes the LFTRs would supply?

I'm not very qualified to be posting in this forum. I'm a fan of Kirk Sorensen—kind of awkward—and other nuclear engineers and science professionals here despite their general gruff dispositions and impatience of idiocy—to be expected. But I am extremely frustrated with the U.S. conservative so-called climate change deniers versus the liberal "save the planet" types. What if a ten-mile-wide asteroid were headed for Earth right now? All this bickering is so very stupid coming from supposedly "smart" people. Call me a freaking dumb ass—I feel like one. One tonne of thorium has the energy of a million tonnes of coal—just for starters. The energy density advantage speaks for itself and no one is listening except the Thorium Energy Alliance?

I'm an Irish Catholic. Meanwhile, I vote Flibe Energy. Their whole philosophy in my view is the absolute BEST all the way around! EVERYTHING depends on energy. Get that right and everything else improves. EVERYTHING! No joke. In Kirk's thesis he highlights how Dr. Seaborg once remarked that the energy-to-dollars equivalent of thorium is THOUSANDS OF TRILLIONS OF DOLLARS. Guaranteed! How stupid am I? Introduce the U.S. Thorium Energy Act right way. Mint the money against the future value of the energy. What did President Trump say in the inaugural? Make America wealthy again? What are we waiting for? Ego aggrandizement? "I am the great one! I figured it all out! Now kneel!" So stupid. This is a big-time group effort.

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Last edited by Tim Meyer on May 07, 2017 3:10 pm, edited 1 time in total.

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PostPosted: May 06, 2017 2:50 pm 
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Tim Meyer wrote:
I'm pretty sure neutrons are WAY too precious for anything other than burning Pu-239 in a way to produce U-233 for the LFTR-23; where Kirk said in the subject report, one LFTR-49 for three LFTR-23s—impressive! But the goal is to get AWAY from U-238 (U-235) and move away from the higher actinides. I thought that was one of the great benefits of thorium! This is the "Energy from Thorium" Thorium Energy Alliance is it not? Thorium is about three times more abundant than uranium. That speaks for itself.

Getting away from needing uranium as fuel is certainly "A goal" but not necessarily "THE goal". There are a number of problems with using uranium as an energy source, weapon proliferation fears is probably on the top of that list. It will be difficult to remove ourselves completely from needing uranium as a nuclear fuel because uranium-235 is the only naturally occurring isotope that is fissile. We might be able to remove the need to enrich uranium with the use of heavy water reactors and other technology, that should reduce fears of nuclear weapon proliferation.

Just so I'm clear here I will say that there is nothing inherently wrong with having the ability to produce nuclear bombs. We live our lives of freedom and comfort because past generations developed nuclear bombs. It becomes a problem when madmen get their hands on the technology as then they become a much greater threat, just as if they had access to any other weapon of mass destruction. This is a genie we cannot put back in the bottle, so long as people know that nuclear bombs are possible, and people have access to dirt or seawater, there will be a threat that someone will extract the uranium and do something evil with it.

Also, I'm not saying that LFTR49 is a bad idea, it's a very good idea. As an engineer I tend to think of ways to "fix" things, even if those things aren't broke. LFTR49 produces neutrons for the bombardment of thorium, producing U-233, an excellent idea. I'm just playing on this theme to see if other valuable products could be made from this. This is a forum dedicated to the uses of thorium for energy but we can't narrow ourselves with this too much or we'd be ignoring the value of thorium as a source of medical isotopes. It's not too far of a leap to think of other variations on this technology, such as the production of Pu-239 for starting more LFTR49 reactors, feeding military power reactors, producing fuel for solid fuel reactors, etc. Thorium is more abundant than uranium so using thorium over uranium is preferable. Even better would be to utilize both as a fuel since that opens us to even more energy possibilities.

This brings to mind an alternative use for the U-233 produced. We have a lot of solid fuel reactors still. I expect that not only will these be operational for a very long time yet but more will be built. What of taking the U-235/U-238 mix of isotopes from the spent fuel and mixing it with some of the U-233 produced to make new solid fuel rods? One big thing holding back MSR technology is that the solid fuel people see it as a threat for their business model. If this can be sold as a means to recycle the spent solid fuel into new solid fuel then this might be more popular.

Another big reason we cannot free ourselves from uranium as a fuel completely is its value as a feedstock for Pu-238. We can get to Pu-238 from thorium but that takes a lot more valuable neutrons than if you start with natural uranium. This leads into my next point on alternative materials for neutron bombardment.

Tim Meyer wrote:
I'm a little concerned about placing a lot of eggs in the targeted alpha therapy basket. I bet there are other and more vital medical isotopes the LFTRs would supply?

I'm sure there are plenty we could dream up. Tc-99m comes to mind as that is what was used for my bone scans. I'll disagree with the "eggs in one basket" here since it sounds like what is being proposed is two paths for the usage of the U-233 produced with LFTR49. One use is as a fuel for LFTR23, the other is as a source for valuable decay products of which one has a potential use for targeted alpha therapy.

With a two fluid reactor design we can think up all kinds of variations on a theme where the core fluid is fissioning and producing heat and neutrons for a blanket salt. This blanket can contain thorium to produce U-233, U-238 to produce Pu-239, or any of a number of elements to produce fuel and non-fuel isotopes. So long as the balance of neutrons is maintained there's a lot of possibilities.

I believe that Flibe Energy succeeded with LFTR49 where Transatomic failed with WAMSR was with an understanding of the chemistry needed. It takes an understanding of nuclear fission to keep those neutrons where they need to be but without the chemical processing beforehand that balance becomes difficult or impossible. WAMSR keeps the chemistry simple but then made the neutron balance hard. LFTR49 added complexity to the chemistry which made the neutron balance easier.

I won't even pretend I understand all the chemistry and nuclear physics here but I do understand algebra. If you put 2 neutrons in and get back 1.9 then you come up negative. If you put 2 neutrons in and get 2.2 back then that little extra can be used in a lot a different ways. Using those neutrons for U-233 production is a great idea. What I was pondering with my previous post was using them to produce more Pu-239, which has a lot of peaceful and not so peaceful uses. I see potential for variations on this theme to produce all kinds of valuable isotopes, or maybe even use it to destroy isotopes that are difficult to dispose of by other means.

I'll wrap up my thoughts here by getting back to where I started, it seemed to me that the article was too quick to get to the conclusion that the uranium extracted from spent LWR fuel could be just thrown away. That uranium is valuable as a fuel. Put it in a HWR/CANDU. Mix in some U-233 to enrich it and put it back in a LWR. Just generally hit it with more neutrons so we can get things like Pu-239 (fuel), Pu-238 (RTG), Tc-99m (bone scans), Am-241 (smoke alarms), Co-60 (industrial radiography), and so on.

At a minimum perhaps we could be satisfied with using uranium for it's density and not just toss it in a hole. That density would come in real handy for weighing things down, radiation shielding, and armor. Don't throw it away.

Tim Meyer wrote:
What if a ten-mile-wide asteroid were headed for Earth right now?

I imagine it'd go something like this...
https://www.youtube.com/watch?v=iVL-xa4aZUo

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PostPosted: May 06, 2017 4:10 pm 
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Kurt Sellner wrote:
What of taking the U-235/U-238 mix of isotopes from the spent fuel and mixing it with some of the U-233 produced to make new solid fuel rods?


Super super bad idea.

Kurt Sellner wrote:
One big thing holding back MSR technology is that the solid fuel people see it as a threat for their business model.


Doesn't matter. Their business model is already dead. It's just that the corpse is still warm.

Kurt Sellner wrote:
If this can be sold as a means to recycle the spent solid fuel into new solid fuel then this might be more popular.


No, putting U-233 into an enriched uranium mix is an incredibly bad idea. Back to the drawing board.

Kurt Sellner wrote:
Another big reason we cannot free ourselves from uranium as a fuel completely is its value as a feedstock for Pu-238.


Nope, Np-237 is the feedstock for Pu-238. We have about 500 kg of Np-237 and vastly more in the worldwide inventory of spent fuel. We have enough for about the next thousand years of Pu-238 demand if we never do another thing. Certainly not a reason to keep the uranium fuel cycle around.


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PostPosted: May 06, 2017 6:44 pm 
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Kirk Sorensen wrote:
Kurt Sellner wrote:
One big thing holding back MSR technology is that the solid fuel people see it as a threat for their business model.


Doesn't matter. Their business model is already dead. It's just that the corpse is still warm.


Is there harm in trying to get the "old guard" of solid nuclear power as allies? If this technology can revive that corpse then we'd see a market for LFTR49 and the solid fuel people will sell it for us. (Again with the wide latitude on "we" and "us" I've used before, as in Americans, humans, or advocates for thorium fuel.)

You may be convinced their market is dead, and you can make a case to me, but do they know the market is dead? Take advantage of their delusion, get them sold on LFTR49 and when that warmed corpse finally cools then we'd still have our MSRs.

I'm just thinking out loud here, none of this is a fully formed idea yet.

Kirk Sorensen wrote:
Kurt Sellner wrote:
If this can be sold as a means to recycle the spent solid fuel into new solid fuel then this might be more popular.


No, putting U-233 into an enriched uranium mix is an incredibly bad idea. Back to the drawing board.


I am probably mistaken but I recall this being proposed somewhere. Failing that as an option I would think that there would be value in this "waste" uranium. This "waste" is in many ways like natural uranium, then use it in existing heavy water reactors, or just as a paperweight, just don't throw it away.

Kirk Sorensen wrote:
Kurt Sellner wrote:
Another big reason we cannot free ourselves from uranium as a fuel completely is its value as a feedstock for Pu-238.


Nope, Np-237 is the feedstock for Pu-238. We have about 500 kg of Np-237 and vastly more in the worldwide inventory of spent fuel. We have enough for about the next thousand years of Pu-238 demand if we never do another thing. Certainly not a reason to keep the uranium fuel cycle around.


What's the feedstock for Np-237? I recall that is U-235, that's where I was coming from. I was not aware of the vastness of the Np-237 reserves, only that NASA was in a panic on finding enough Pu-238 for the foreseeable future. I'm aware that Np-237 can be extracted from a LFTR23 if more is needed in the future, negating any future reliance on the uranium cycle for Pu-238.

Assuming that you make your case to the world that we don't need the uranium fuel cycle and everyone abandons it then is this uranium worthless? What of using it as a non-fissile stand in for U-233 in uranium chemistry research?

I'll go back to the original article:
Quote:
The right way to do it, according to Sorensen, is to separate all uranium isotopes from the process: U235, U236 and U238 are hardly radioactive and are present in the waste in approximately the natural composition of U ore. So they can be discarded.


Perhaps I misunderstood the article, by "discard" are we to bury it in the desert and forget it even exists? Or are we merely "setting it aside" since it's not part of the discussion any more, we'll still use it but just not in this reactor or not as an energy source?

This gets to a video I saw of Dr. Stephen Boyd where he laid out chemical processes that MSRs could perform and non-fuel uses of thorium. I see parallels here with LFTR49 and uranium, I see non-energy applications for this and non-fuel uses for uranium.

Thank you, Mr. Sorensen, for taking the time to reply.

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PostPosted: May 07, 2017 3:02 pm 
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Kurt Sellner wrote:
It will be difficult to remove ourselves completely from needing uranium as a nuclear fuel because uranium-235 is the only naturally occurring isotope that is fissile.
Based on the tone of our host's response that is consistent with the whole Flibe Energy philosophy and the spirit of the subject report: once the thorium fuel cycle is established, natural uranium enrichment (expensive) will become obsolete given a "critical mass" of U-233 production (that spontaneously develops the U-232 chain that leads to the nasty gamma emitters?) and the (evidently) inevitable retirement of the uranium fuel cycle.
Kurt Sellner wrote:
Tim Meyer wrote:
What if a ten-mile-wide asteroid were headed for Earth right now?

I imagine it'd go something like this . . .
https://www.youtube.com/watch?v=iVL-xa4aZUo
Well, Kurt? THAT was entertaining. Is this a sign you have a sense of humor?—kidding! My point is that I vote for the Flibe Energy plan and I believe once the power brokers open their minds and give it a chance, they'll see it is the BEST plan. What if the tens of billions spent on Vogtle/Summer had been spent on Flibe Energy?

I know: Our national nuclear laws are locked in on solid-fueled reactors because Director Shaw disagreed with the "all of the above" strategy—well, the other one of two (liquid metal fast and molten salt graphite).

I think SRS is a great opportunity to implement the LFTR-49/23 machines because it would kill two birds with one stone given that there's already tens of tonnes of WG Pu there that could be put to good use. But so much is classified in this arena. A regular science-informed (trans-scientist) citizen as myself cannot know if U.S. national security is hedging?

I may be naive but what could be a greater national security issue than sound energy technology policy? Flibe Energy deserves a preferred contract on principles, IMHO naive as it may be to say. I may be whacked, but given that excessive atmospheric carbon loading together with geologic carbon that will run out before thorium all amounts to something folks call "unwise", our nation needs to reallocate general revenues to start cashing in on that million trillion dollars worth of thorium energy Dr. Seaborg was talking about.

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