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PostPosted: Sep 23, 2017 11:48 pm 
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Kurt Sellner wrote:
Kirk Sorensen wrote:
If you're running an MSR on greater than 5% enriched uranium fuel, you're running it on HEU. The only difference being that the government downblended it before you got it, and then you downblend it even further.


Is that a complaint against Terrestrial's IMSR or against the current enriched uranium industry?

Kirk Sorensen wrote:
Commercial enrichment facilities don't make enrichments greater than 5%. Governments make it from HEU.


What is preventing commercial enrichment facilities from producing 5% U-235? If there is a legal restriction then while we lobby the government for regulations that allow MSRs to get built then we should also lobby for a rule change to allow the production of the fuel needed for them. If it's a matter of not having a market for 5% U-235 that keeps commercial enrichment from producing it then the problem solves itself with the construction of reactors that will need it as fuel.

The lack of commercial 5% enriched uranium production shouldn't count against IMSR any more than a lack of commercial thorium production should count against LFTR.


AFAIK there is no legal restriction on LEU >5% and <20% enrichment.
The issue is there isn't much of a commercial market for that, hence enrichment companies just aren't interested in that.
Its a chicken and egg problem. Too little demand = no supply, which perpetuates the problem of too little demand. Terrestrial doesn't want to depend on a type of fuel for which there isn't much (or none at all) supply.
The only types of operational civilian and commercial scale reactors in the world that need fissile content above 5% are fast reactors, and those don't work too well on U235, they need higher levels of Pu239 on their cores instead.
If Terrestrial can start with <5% enrichment pure Uranium fuel, its a better start because it avoids a lot of certification issues.
If you look at presentations on proliferation issues that any MSR must face, like the complexity of keeping track of fissile/fertile stockpiles on a reactor that continuously looses noble gasses and where the fuel isn't divided on discrete units such as fuel pins, any MSRs have enough issues without throwing Thorium and Uranium enrichment above 5% challenges.
The easier the better, aka the KISS principle.
Don't make it complicated where you don't absolutely need to.
Its easy to dream its soooo hard to achieve.
Once there are dozens or hundreds of operational MSRs in the market, it will be so much easier to create a market for DMSR 80% Th232+15% U238+5% U235 fuel.

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PostPosted: Sep 24, 2017 1:34 am 
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macpacheco wrote:
AFAIK there is no legal restriction on LEU >5% and <20% enrichment.

That's what I thought. So, the problem is purely economics?

macpacheco wrote:
The issue is there isn't much of a commercial market for that, hence enrichment companies just aren't interested in that.
Its a chicken and egg problem. Too little demand = no supply, which perpetuates the problem of too little demand. Terrestrial doesn't want to depend on a type of fuel for which there isn't much (or none at all) supply.

Sounds like an interesting compromise to have to make. Flibe is betting on it's easier to get thorium than >5% U-235 and Terrestrial is betting on it being easier to get >5% U-235 than thorium. I know that's simplifying the engineering decisions greatly but that does seem like one way to summarize the problem.

macpacheco wrote:
If Terrestrial can start with <5% enrichment pure Uranium fuel, its a better start because it avoids a lot of certification issues.

I'm quite certain that Terrestrial would rather not have to use >5% U-235 as fuel but that's what they calculated as the "best" fuel. I'm sure if they could design a reactor to run off of discarded banana peels they'd do that, that would solve a lot of certification issues too.

macpacheco wrote:
The easier the better, aka the KISS principle.
Don't make it complicated where you don't absolutely need to.

I agree. It seems that to simplify the reactor Terrestrial has complicated the fuel.

macpacheco wrote:
Once there are dozens or hundreds of operational MSRs in the market, it will be so much easier to create a market for DMSR 80% Th232+15% U238+5% U235 fuel.

Yes, another chicken and egg problem. It's going to be very hard to get the first MSR online, the 100th won't be nearly as difficult. It's not like it's impossible for Terrestrial to get 5%, 12%, 18%, or whatever LEU, they'll just have to ask the government very nicely for it and write a large check. LFTR is going to have a similar problem, getting the fuel it needs until a market develops.

Thinking about what IMSR offers that LFTR does not some more I have to wonder, could either be used for marine propulsion? I think of the Russian nuclear icebreakers and if MSRs could be used for something like that instead of a solid fuel reactor. If Terrestrial can deliver on the promise of a reactor in the 150MWt range then that sounds like just about the right size for a heavy icebreaker.

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PostPosted: Sep 24, 2017 6:29 pm 
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There are also safety issues with higher enrichment. From https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&cad=rja&uact=8&ved=0ahUKEwiS8ejt-r7WAhUqAcAKHUxbBnYQFghTMAY&url=http%3A%2F%2Fwww.princeton.edu%2F~aglaser%2Flecture2007_makingheu.pdf&usg=AFQjCNEoNmOMsWp2Xc8ZM_GCegQint-YYg , page 5, we see that the critical mass of 5% enriched uranium with a beryllium-reflected sphere is very large and might be infinite. At 20%, it is 144 kg. If one is processing a soluble form of uranium, and it drops into water, then the issues are much more difficult. IIRC, there was a fatal criticality accident involving unexpectedly highly enriched uranium dissolved in water.

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PostPosted: Sep 24, 2017 9:55 pm 
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pstudier wrote:
There are also safety issues with higher enrichment. From https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&cad=rja&uact=8&ved=0ahUKEwiS8ejt-r7WAhUqAcAKHUxbBnYQFghTMAY&url=http%3A%2F%2Fwww.princeton.edu%2F~aglaser%2Flecture2007_makingheu.pdf&usg=AFQjCNEoNmOMsWp2Xc8ZM_GCegQint-YYg , page 5, we see that the critical mass of 5% enriched uranium with a beryllium-reflected sphere is very large and might be infinite. At 20%, it is 144 kg. If one is processing a soluble form of uranium, and it drops into water, then the issues are much more difficult. IIRC, there was a fatal criticality accident involving unexpectedly highly enriched uranium dissolved in water.


Pretty minor issue - easily resolved by design provisions (batch size, neutron poisons).

In any case, arguments, or even presented facts running towards the implication of, "we shouldn't use technology X because it leads to/could lead to/has led to, Y deaths", are weak and counter-productive. Technology is risky. Period. Even apparently innocent and cute technologies such as pillows and cords kill many a year. You don't want to start googling the number of children that suffocate in pillows or cords, or the number of people that die from falling from stairs. It does not follow that we should go out and claim we should not have such technologies on account of death toll. We can ban the stair industry, but apart from being inconvient, draconian and even silly, you'd have to ask how many additional deaths would occur from motor vehicle accidents since single story buildings take up so much more space, requiring increased travel distance and thus miles driven.

A ban or non-use decision on technology is only rationalized if it meets a simple condition: the ban saves more lives, globally, than not banning.

There are not many technologies that meet this condition. Ozone depleting driving or working gasses are a good example - alternatives are available, at lower cost even, and the ban saves many lives from increased skin cancer and other UV exposure effects compared to non action. But it is only because alternatives are readily available that the decision to ban CFCs became quite easy.

Banning stairs is silly, but that doesn't mean we can't minimize risks within reason: stairs can be provided with high-friction surfaces and railings to minimize slipping accidents. We could also provide each stairwell with robots that grab and save anyone that slips, but now we have clearly left the bounds of reasonable-ness: the cost would be ridiculous. Installing elevators in big buildings is a potential way to reduce the risk of stairs since elevators are much safer and are more convenient to use so people would naturally choose it over the stairwell.

I honestly can't think of a technology that has killed fewer people than criticality accidents with LEU fuel (<19%). Pillows, chords and stairs are many orders of magnitude more dangerous.

Campaigning against IMSR because one thinks LFTR is better so we should burn more fossil fuels in the meanwhile certaintly does not meet the condition. It is more a case of "perfect is the enemy of done". Further, what is up with this dichotomy in the first place? Competition is a good thing and a sign of a promising idea, rather than a one-man-has-a-good-idea-show. If you are afraid of competition you should not be in a private business and certainly not in the business of innovation. Competition is what keeps us sharp, and honest.

In any case, thorium advocates better get comfortable with higher reactive fissile materials, because a thorium reactor CAN NOT be started with 5% LEU or it's equivalent in transuranic material. It needs something one-heck-more-reactive to start up with, and the implications of this - both technical and regulatory - need to be understood and managed appropriately.


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PostPosted: Sep 25, 2017 5:47 pm 
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Cyril R wrote:
In any case, thorium advocates better get comfortable with higher reactive fissile materials, because a thorium reactor CAN NOT be started with 5% LEU or it's equivalent in transuranic material. It needs something one-heck-more-reactive to start up with, and the implications of this - both technical and regulatory - need to be understood and managed appropriately.


Here's how I understand the complaint against IMSR. With LFTR there is no doubt there would have to be a starter fuel load of something like U-233, Pu-239, or (not like anyone would actually do this) supergrade U-235. This is a starter load of fuel, it's needed precisely once to get the reactor started. After that a LFTR would require only thorium as makeup fuel. On the other hand IMSR is a burner, the starter fuel and makeup fuel would both need to be enriched fuel. If we assume similar fuel consumption rates, a 60 year operational life for LFTR, and an annual charge of fuel for IMSR, then we'd see 60x the enriched fuel burn for IMSR compared to LFTR. I'm just making up numbers so insert more realistic values if you can find them.

Taking this further is that as a LFTR is decommissioned the fuel that is drained from it can be used to start another LFTR. If we assume an efficient enough design where a LFTR can produce more uranium than it consumes then it is entirely possible that in the operational life of a given LFTR it produces enough U-233 (and maybe even Pu-239) to start several other LFTRs. With IMSR someone would have to keep going back to some enriched fuel well to draw from to keep operational. With LFTR the well is drawn from once and then potentially that LFTR becomes another well to draw from for other LFTRs.

Another related complaint on IMSR is that once you put that enriched fuel into the reactor there is no getting that back. With a solid fuel reactor you might have a fuel rod with (again pulling a number out of the air) 12% enriched U-235 as a starter fuel rod. Perhaps you can let it burn down to 3% before it has to be replaced, so long as the average among the rods is above 5% it keeps going. If for some reason the reactor needs to be shutdown early you can pull that enriched rod back out. At that time it might be 10% U-235, or maybe 8%, but it's not going to be 5% like the other rods. That preserves at least some of the investment in the enrichment.

With IMSR it might need 5% U-235 in the fuel to keep going. Once someone drops in 12% enriched makeup fuel it's gone, you cannot get that back even if you shutdown early. What you are going to get out is that average of what was put in (12%) and what was in there before (5%). Presumably the makeup fuel is quite small compared to the total fuel in the reactor so what comes out would be only marginally better than 5%.

In a solid fuel reactor pulling out a rod that's burned down to 3% immediately increases the average enrichment in the reactor. You gain by adding and removing. With IMSR removing fuel doesn't increase the average enrichment, it only makes room for more enriched fuel. All else equal, unless I missed something, an IMSR will need more enriched fuel than a comparable solid fuel reactor. That means going back to the enriched fuel well more often. The well, as it is now, being the government and their military uranium enrichment facilities.

As usual with my little "thought experiments" I hand waved over details. If I went too far with my examples then please offer corrections and clarifications.

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PostPosted: Sep 26, 2017 6:04 am 
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Kurt Sellner wrote:
Cyril R wrote:
In any case, thorium advocates better get comfortable with higher reactive fissile materials, because a thorium reactor CAN NOT be started with 5% LEU or it's equivalent in transuranic material. It needs something one-heck-more-reactive to start up with, and the implications of this - both technical and regulatory - need to be understood and managed appropriately.


Here's how I understand the complaint against IMSR. With LFTR there is no doubt there would have to be a starter fuel load of something like U-233, Pu-239, or (not like anyone would actually do this) supergrade U-235. This is a starter load of fuel, it's needed precisely once to get the reactor started. After that a LFTR would require only thorium as makeup fuel. On the other hand IMSR is a burner, the starter fuel and makeup fuel would both need to be enriched fuel. If we assume similar fuel consumption rates, a 60 year operational life for LFTR, and an annual charge of fuel for IMSR, then we'd see 60x the enriched fuel burn for IMSR compared to LFTR. I'm just making up numbers so insert more realistic values if you can find them.

Taking this further is that as a LFTR is decommissioned the fuel that is drained from it can be used to start another LFTR. If we assume an efficient enough design where a LFTR can produce more uranium than it consumes then it is entirely possible that in the operational life of a given LFTR it produces enough U-233 (and maybe even Pu-239) to start several other LFTRs. With IMSR someone would have to keep going back to some enriched fuel well to draw from to keep operational. With LFTR the well is drawn from once and then potentially that LFTR becomes another well to draw from for other LFTRs.

Another related complaint on IMSR is that once you put that enriched fuel into the reactor there is no getting that back. With a solid fuel reactor you might have a fuel rod with (again pulling a number out of the air) 12% enriched U-235 as a starter fuel rod. Perhaps you can let it burn down to 3% before it has to be replaced, so long as the average among the rods is above 5% it keeps going. If for some reason the reactor needs to be shutdown early you can pull that enriched rod back out. At that time it might be 10% U-235, or maybe 8%, but it's not going to be 5% like the other rods. That preserves at least some of the investment in the enrichment.

With IMSR it might need 5% U-235 in the fuel to keep going. Once someone drops in 12% enriched makeup fuel it's gone, you cannot get that back even if you shutdown early. What you are going to get out is that average of what was put in (12%) and what was in there before (5%). Presumably the makeup fuel is quite small compared to the total fuel in the reactor so what comes out would be only marginally better than 5%.

In a solid fuel reactor pulling out a rod that's burned down to 3% immediately increases the average enrichment in the reactor. You gain by adding and removing. With IMSR removing fuel doesn't increase the average enrichment, it only makes room for more enriched fuel. All else equal, unless I missed something, an IMSR will need more enriched fuel than a comparable solid fuel reactor. That means going back to the enriched fuel well more often. The well, as it is now, being the government and their military uranium enrichment facilities.

As usual with my little "thought experiments" I hand waved over details. If I went too far with my examples then please offer corrections and clarifications.


And all this is arguing over 0.2 cent/kWh for the fuel. aesthetically pleasing, but totally pointless economically.

The real economic problem is capital cost. You have to get this down. If you think having a full-blown reprocessing plant at each reactor site will help reduce capital costs, or that this helps with commercial technology development and licensing, we can agree to disagree. If you think having availability of bomb grade uranium for startup charges is going to be easy peasy, and that this (togethe with a non standard fuel cycle) will help with expedient licensing, we can further agree to disagree. If you think that the IMSR's simplification and modularization effort in the MSR field is not worth pursuing, we can completely agree to disagree some more.


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PostPosted: Sep 26, 2017 7:07 pm 
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Cyril R wrote:
If you think having availability of bomb grade uranium for startup charges is going to be easy peasy, and that this (togethe with a non standard fuel cycle) will help with expedient licensing, we can further agree to disagree.


I wouldn't characterize it as "easy-peasy" and I don't think anyone else would, but any sustainable nuclear fuel cycle will involve a fissile species chemically distinct from a fertile species. It will either be plutonium in uranium-238 in a fast-spectrum reactor, or uranium-233 in thorium in a thermal or fast-spectrum reactor. If we continue to "burn" uranium-235 in thermal spectrum reactors then we will be just as the anti-nuclear forces accuse us: an unsustainable option not worth further pursuit.


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PostPosted: Sep 27, 2017 12:54 am 
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Cyril R wrote:
And all this is arguing over 0.2 cent/kWh for the fuel. aesthetically pleasing, but totally pointless economically.


A quick Google search tells me that your cost estimate for fuel is close enough to real numbers that I'm not going to dispute it. A quick Google search also tells me that the typical rate for electricity in the USA is about 10 cents/kWh and that the typical profit margin for electricity is less than 10%. So, a typical power plant can expect less than 1 cent of profit for every kWh sold. You can say that 0.2 cents/kWh is pointless to argue over but I believe otherwise. This would especially be true if we're talking about a power plant that produces 1 GW of electricity, for something like 7000 or 8000 hours per year, for likely 40 or 60 years, and small numbers like 0.2 start to look really big. That's also a lot of electricity to spread out any increase in capital expenses.

Cyril R wrote:
The real economic problem is capital cost. You have to get this down. If you think having a full-blown reprocessing plant at each reactor site will help reduce capital costs, or that this helps with commercial technology development and licensing, we can agree to disagree.


Enriching fuel has capital expenses too, and non-trivial operating expenses. We can assume these costs are zero so long as the government is giving away blended down nuclear warhead cores but that well will run dry real quick if nuclear power has any growth.

Cyril R wrote:
If you think having availability of bomb grade uranium for startup charges is going to be easy peasy, and that this (togethe with a non standard fuel cycle) will help with expedient licensing, we can further agree to disagree.


I believe that any government willing to sell blended down weapon grade uranium for fuel is going to either run out of stockpiled uranium to sell at some point, or run out of enrichment capacity, if there's a new batch of nuclear reactors coming on line that need enriched uranium to start. Civilian nuclear power will need civilian enrichment capacity to meet this need, and at a price that makes economic sense, or civilian nuclear power will have to find a way to minimize (or eliminate) the need to go to the government for weapon grade uranium. In reality the solution will likely be a combination of the two.

Cyril R wrote:
If you think that the IMSR's simplification and modularization effort in the MSR field is not worth pursuing, we can completely agree to disagree some more.


I believe IMSR is a good idea. I also believe LFTR is a good idea. I also believe solid fuel reactors, especially heavy water reactors, have a place in the future of nuclear power. I foresee a future where there's a variety of nuclear reactor designs competing in the market.

The argument over IMSR vs. LFTR is largely the argument over burner vs. breeder. Uranium enrichment is expensive, not just economically but also politically. At the same time we cannot do without enrichment, since enriched uranium is needed to jumpstart the breeder economy. Any nation that has nuclear power will want some enrichment as a fail-safe to protect their investment in breeders, while at the same time they'll want to minimize that enrichment to avoid the political and economic costs. A balance will have to be found.

I believe we'll keep using burners. They might be only for marine propulsion, research reactors, and so on where being small is as important as being cheap to fuel. The fuel they burn will likely come from a mix of breeders and enrichment.

To agree to disagree on something assumes I've come to some conclusion to disagree about. I've concluded that uranium enrichment is best avoided as much as we can, but it will not be eliminated. I've concluded that while burners have an increased cost in fuel the power density advantage they can achieve over breeders means that they will have a place in the market, perhaps a small part of the market but not zero. I've concluded that both IMSR and LFTR are MSR technologies that are worth pursuing. Solid fuel reactors will likely have a place too, again likely a small part. I've also concluded that a conclusion is just a convenient place to stop thinking. If there's something new that comes along then I'll have to start thinking again until I come to a new convenient place to stop.

It seems to me that solid fuel reactors can have a flexibility in fuel types that MSRs cannot have because the fuel is not mixed when added. Even calling them "solid fuel" reactors might be something of a misnomer in the future. Even though it might share a lot of design features with existing solid fuel reactors, primarily that of a fuel rod, the fuel inside the rod may in fact be molten while operating. This flexibility of fuel types may in fact make solid fuel reactors the "garbage disposer" that TransAtomic has promised.

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PostPosted: Sep 27, 2017 10:19 am 
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Quote:
A quick Google search tells me that your cost estimate for fuel is close enough to real numbers that I'm not going to dispute it. A quick Google search also tells me that the typical rate for electricity in the USA is about 10 cents/kWh and that the typical profit margin for electricity is less than 10%. So, a typical power plant can expect less than 1 cent of profit for every kWh sold. You can say that 0.2 cents/kWh is pointless to argue over but I believe otherwise. This would especially be true if we're talking about a power plant that produces 1 GW of electricity, for something like 7000 or 8000 hours per year, for likely 40 or 60 years, and small numbers like 0.2 start to look really big. That's also a lot of electricity to spread out any increase in capital expenses.


In this case I wish you good luck in having full onsite fuel reprocessing for under 0.2 cents/kWh. You're going to need it.

Heck just the R&D costs of the onsite fuel reprocessing is way out of reach of what a private startup company can fund, so it's totally academic anyway.

Apples in the store versus oranges yet to be invented.

Quote:
Enriching fuel has capital expenses too, and non-trivial operating expenses. We can assume these costs are zero so long as the government is giving away blended down nuclear warhead cores but that well will run dry real quick if nuclear power has any growth.


Used to be pretty bad with diffusion plants - massive facilities, enormous energy bills. With modern centrifuges, enrichment is cheap. Moreover, it is a commodity; plutonium or HEU for starting up a LFTR is not. Again, apples in the store versus oranges yet to be invented, tested, planted, and grown then shipped. And then hope nothing goes wrong in any of these steps.

Quote:
The argument over IMSR vs. LFTR is largely the argument over burner vs. breeder.


My issue is most advocates of LFTR reduce everything to the fuel cycle argument of breeder vs burner. There is so much more to a reactor than fuel cycle, indeed the historic myopic focus on reactor and fuel cycle has led to serious technical, regulatory, and economical problems. There are considerations of meeting regulations, proliferation requirements (or plan for applying high cost and lengthy and risky political pressure to change the regs), modularization, simplification (onsite fuel reprocessing is not simple to use an understatement), reliability, testability, inspectability, manufacturability, supply chain development, RD&D requirements and resources needed (setting up experiments on chemistry, thermalhydraulics, safety systems, etc. etc.), getting investors on board, design attention to balance of plant, instrumentation, controls, plant electrical, civil engineering (historically weak points in new reactor designs), the list goes on and on and on.


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PostPosted: Sep 27, 2017 4:54 pm 
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Cyril R wrote:
In this case I wish you good luck in having full onsite fuel reprocessing for under 0.2 cents/kWh. You're going to need it.


Well, that is the gamble the Flibe and Terrestrial has made. Flibe is betting on being able to get online processing costs low enough to be economical. Terrestrial is betting on an inexpensive source of enriched uranium. I believe both have a good chance in the market. Those two aren't the only players in this game either.

Cyril R wrote:
Heck just the R&D costs of the onsite fuel reprocessing is way out of reach of what a private startup company can fund, so it's totally academic anyway.

Apples in the store versus oranges yet to be invented.


This does not have to be funded by private startup. There's an opportunity for a public/private partnership. The US Navy has been quietly funding fusion and fission energy research for a very long time. Large companies have interests in developing this technology too. In both cases we're not likely to hear about it for years after the funding was made.

Cyril R wrote:
Quote:
Enriching fuel has capital expenses too, and non-trivial operating expenses. We can assume these costs are zero so long as the government is giving away blended down nuclear warhead cores but that well will run dry real quick if nuclear power has any growth.


Used to be pretty bad with diffusion plants - massive facilities, enormous energy bills. With modern centrifuges, enrichment is cheap. Moreover, it is a commodity; plutonium or HEU for starting up a LFTR is not. Again, apples in the store versus oranges yet to be invented, tested, planted, and grown then shipped. And then hope nothing goes wrong in any of these steps.


I agree that LEU is a commodity. I won't even pretend I can speak for Flibe Energy but I can read their website, there's no need for plutonium or HEU to start a LFTR. The potential to use recovered plutonium from LWR and HWR spent fuel was offered as a possibility to bootstrap the thorium economy was discussed in another thread. India has their three stage nuclear power program to reach a thorium fuel cycle without the need for enrichment. You can call them fools for trying, but I won't.

Cyril R wrote:
Quote:
The argument over IMSR vs. LFTR is largely the argument over burner vs. breeder.


My issue is most advocates of LFTR reduce everything to the fuel cycle argument of breeder vs burner. There is so much more to a reactor than fuel cycle, indeed the historic myopic focus on reactor and fuel cycle has led to serious technical, regulatory, and economical problems. There are considerations of meeting regulations, proliferation requirements (or plan for applying high cost and lengthy and risky political pressure to change the regs), modularization, simplification (onsite fuel reprocessing is not simple to use an understatement), reliability, testability, inspectability, manufacturability, supply chain development, RD&D requirements and resources needed (setting up experiments on chemistry, thermalhydraulics, safety systems, etc. etc.), getting investors on board, design attention to balance of plant, instrumentation, controls, plant electrical, civil engineering (historically weak points in new reactor designs), the list goes on and on and on.


I agree, it's more than just the fuel cycle. There's issues of proliferation concerns to deal with. Enrichment may be cheap but it's not free, and enrichment is politically difficult in many cases. India knows this, which is why they are starting their nuclear power program with heavy water reactors.

LFTR doesn't need enrichment to work. To be fair neither does IMSR. If there is no enrichment to feed IMSRs then there will have to be a fleet of HWRs, or some other breeder reactors, to provide the fuel it needs. If IMSRs use fuel from breeders then there needs to be chemical processing of the fuel, and it'd look a lot like what LFTR would need. The difference being IMSR fuel processing is an off-site batch process but LFTR is an on-site continuous process.

Perhaps the argument is then over using enrichment or chemical processing for the nuclear fuel. LFTR will need chemical processing of fuel to work. IMSR can be made to work with either enrichment or chemical processing. Chemical processing and enrichment take a lot of energy, so it would make sense to keep the your "well" of energy close to where it's used, kind of like putting the steel mill close to the coal mine. Would it not make sense to have your IMSR and centrifuges close together? If one is using chemical processing of the fuel instead of enrichment then it would seem wise to put the chemical processing close to the reactors that produce the fuel, no? How is that any different than having LFTR also keep the processing close to the reactor?

What does the future look like? I don't know. One future I can envision is sitting on the couch and watching an episode of "Ice Road Truckers" where they bring an IMSR "can" out to some diamond mine in northern Canada. Once there they'll load up a spent "can" for the trip back. While on the trip back they'll show the truck driver talking about how the reactor core he's carrying will end up at some American chemical processing plant where they use "this thorium stuff" to make a new can he'll have to bring out next season. Then he'll talk about how business was better years ago when he was trucking out diesel fuel and bringing back coal, before thorium made trucking less profitable.

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PostPosted: Sep 27, 2017 7:36 pm 
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Fissile is the real stuff of nuclear reactors. Rest is just its management.
Control and maximizing the conversion of fertile to fissile frees it from fuel shortage. Enrichment is the trick for initial LWRs. For breeders and thorium reactors you need external fissile feed. Aqueous processing was invented for weapons plutonium. It is the way of commercial processing now.
We need to develop high temperature processing involving chloride/fluoride volatility and electrolysis.
Temporarily, RG plutonium in spent LWR fuel could be extracted by known ways and used.


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PostPosted: Sep 27, 2017 8:09 pm 
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Location: Alabama
Kurt Sellner wrote:
One future I can envision is sitting on the couch and watching an episode of "Ice Road Truckers" where they bring an IMSR "can" out to some diamond mine in northern Canada. Once there they'll load up a spent "can" for the trip back.


You can imagine that future all you want, but the reactor vessel is not a transport cask. The requirements for a transport cask in the US are very stringent, and there's no way a reactor vessel can achieve them. I'm not sure if transport casks requirements are much different in Canada, but I imagine they're similar. No, trucks won't be carrying away reactor cores as "cans"...


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PostPosted: Oct 02, 2017 3:48 am 
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Joined: Apr 19, 2008 1:06 am
Posts: 2233
Ah! The NIMBY once again. It is NIMBY at Yucca too!


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