Energy From Thorium Discussion Forum

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PostPosted: Nov 21, 2009 7:11 am 
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Any use of a fast reactor with chloride salts will require 37Cl isotope separation. There is a thread dealing with use of eutectic metal based fuel.
viewtopic.php?f=2&t=1678&hilit=Eutectic+metal
Sch a reactor shall use metallic uranium and plutonium which can quickly scale up fast reactors and really build up fissile feed for thorium too. Indians are unsure of any fluid fuel so far and are using oxide fuel and a thorium blanket in the PFBR to avoid any political setback in case of a lack of success. They are also working on solid metallic fuel. It is frequently stated by the Chairman Indian AEC that they shall collect fissile feed for a few decades before starting thorium use on an industrial scale. Meanwhile research on thorium powered reactors (AHWR) goes on.
I wish they would simultaneously continue research on fluid fuel carriers and salt and lead-Bismuth coolants. I feel apprehensive about fire prone sodium.
I think I have read somewhere (http://www.energyfromthorium.com/pdf/FFR_chap20.pdf) solubility in lead/Bismuth varies as Pu>U>Th. Pu metal, on the other hand, gives problems in solid state due to volume variations. Pu can be therefore be fruitfully carried in a lead solution with an interior U blanket and an exterior Th blanket.


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PostPosted: Nov 21, 2009 1:06 pm 
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There is absolutely no good reason to reject plutonium. I think it’s a key component of the future, if there is, in fact, to be a future at all. We need plutonium, more of it, lots more of it. That’s what I personally want for all of that depleted uranium, a raw material for Pu-239.

We certainly dont need Pu. Theres just too much uranium to ever consider utility of using plutonium. The premise of using Pu239 is if we're in any sort of fissile shortage. It will allways be more economic to mine more or enrich tailings than to bother with fast reactors at any premium.

Now if you can design fast reactors that operate at a discount to either current infrastructure or any other thermal regime (like LFTR) it might make sense. But absent fissile fuel shortage, theres no way I can see fast reactors being less expensive to build and run than thermal reactors.


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PostPosted: Nov 21, 2009 3:05 pm 
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NNadir,

Your position seems to presume that we can't mine enough fissile to meet the start-up needs of the coming reactor fleet.
It appears to me that we have several plausible ways to convert 235U into 233U (or 239Pu) with fairly decent efficiencies.
Suppose we want to start-up 10,000 GWe worth of reactors. Further suppose each requires 2 tonnes fissile as the startup charge.
We then need 20,000 tonnes fissile. Assuming we get something like 0.5% u235 from natural uranium it means we need 4 Mtonnes natural uranium to start the whole fleet. The current estimate from http://www.world-nuclear.org/info/inf75.html is that the we have 5.5Mtones of "Reasonably Assured Resources plus Inferred Resources, to US$ 130/kg U, 1/1/07, from OECD NEA & IAEA, Uranium 2007: Resources, Production and Demand ("Red Book")." This is likely a significant underestimate of the supply.

To put this into perspective, the current fleet of 500GWe worth of reactors needs something like 500 tonnes fissile per year so we are talking about roughly 40 years worth of fuel. It will take us longer than 40 years to build 10,000 reactors so we are actually talking about a mining and enriching capacity here that is similar to the existing capacity.

In other words, the world already knows where to get more than enough u235 to satisfy the start up charge requirements for even an extremely large fleet of reactors. I'm not sure we ever need to build true breeder reactors. At a minimum, to justify building breeders on a significant scale one would need to show that the cost of producing surplus fissile using the breeder is less than the cost of supply fissile by mining, enriching, and cleaning up the natural uranium mines. I suspect that will be a very difficult challenge to meet.

As far as I can tell we must develop a LFTR reactor and we need to have a means to convert 235U to 233U with reasonable efficiencies. Once this is done, I don't see the need for other reactor types.


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PostPosted: Nov 21, 2009 4:19 pm 
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Lars wrote:
The current estimate from http://www.world-nuclear.org/info/inf75.html is that the we have 5.5Mtones of "Reasonably Assured Resources plus Inferred Resources, to US$ 130/kg U, 1/1/07, from OECD NEA & IAEA, Uranium 2007: Resources, Production and Demand ("Red Book")." This is likely a significant underestimate of the supply.

Unfortunately supply estimates do not take into account politics.

Jagdish has reminded us a number of times on this forum, of the difficulties of starting & operating U mines.

Canada may be the world's largest supplier of U, but we face those issues here just the same - if not more so (compared to, say, Kazakhstan, which will soon replace Canada as the world's largest U suplier).

Its a pretty safe bet that getting U mine operating licenses is going to become increasingly more difficult and costly in the future, courtesy of "green" politics.

Shall I re-post the long series of articles from various countries documenting exactly this ? (....again ?)

Anyway, this is something of a non-issue, since U/Pu "breeders" need not be LMFBRs, nor do they need to involve traditional off-site reprocessing of solid fuel.....


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PostPosted: Nov 21, 2009 7:18 pm 
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I find it extraordinarily implausible that opening mines and expanding uranium production is a less reliable source of fissile material than breeders, no matter what political interference you try to imagine.


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PostPosted: Nov 21, 2009 11:28 pm 
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Outside some Canadian mines, the uranium ores have less than 0.1% uranium and the grade is typically expressed in ppm. I have not lately heard of a four figure grade. A 1000 ton uranium mining shall require a million tons (or more) of ore removal. India have problems in Meghalaya province since the nineties and reactors constructed could not be operated due to uranium shortage. This motivated the PM to start dialog with President Bush ( In face of strong opposition) which helped import uranium from Russia, Kazakhstan and France (mined in Niger). There is a different politics which is holding up import of uranium from biggest exporters Australia and Canada.
I think, in fact am convinced, that it is better to burn U238 in fast reactors and to create fissile isotopes for thorium fuel than to depend on opening additional uranium mines. Additional uranium mining is desirable but risky and undependable. Depleted uranium is better used in fast reactors than in anti-tank ammunition.
I believe India would go for fast reactors in a big way if Russia could and UK would sell surplus reactor grade Plutonium as reactor fuel.


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PostPosted: Nov 22, 2009 1:31 pm 
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jagdish wrote:
Outside some Canadian mines, the uranium ores have less than 0.1% uranium and the grade is typically expressed in ppm.

Whats your point? Even at 100ppm the energy density is vastly higher than coal even in LWR once through fuel cycles. If India wished they could have opened up uranium mines in low ore grades domestically a long time ago for far less than any breeder project.

Fuel is not now nor will it ever be a constraint in nuclear power development.


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PostPosted: Nov 22, 2009 7:44 pm 
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Seriously, if Rossing with 300ppm hard rock ores can turn a profit after the uranium price crashed with only the infrastructure of Namibia, India is simply doing it wrong. And I guarantee that their little toy will generate far less fissile material for the investment than any mine would.


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PostPosted: Nov 22, 2009 8:05 pm 
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dezakin wrote:
Seriously, if Rossing with 300ppm hard rock ores can turn a profit after the uranium price crashed with only the infrastructure of Namibia, India is simply doing it wrong.

In fact Rossing was considering closing the mine after the uranium price crashed. They were losing money. You MUST know that.
How do labour and federal tax levies in Namibia compare to other places ?


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PostPosted: Nov 22, 2009 11:06 pm 
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Lars:

I can't see one good reason, from an external cost standpoint, for mining more uranium and going through the dubious process of isotope separation - the only nuclear power technology that is inherently dual use, weapons and power - creating even more so called "depleted uranium," and this in the form of UF6.

It is not wise in my view to mine uranium.

There are physics differences between plutonium and U-233, of course, particularly with delayed neutrons, but the fact is that there are many nuclear reactors around the world that operate on MOX and do so quite well - these challenges have demonstrably been met.

The situation with respect to U-238 and Th-232 are analogous: Both are just one neutron away from fissile nuclei. Both are present with large inventories in already mined material. Both have been considered "waste products" although the thorium waste product largely derives from the former use of lanthanides in television tubes.

Done right, both are proliferation resistant, in spite of the blather to the contrary by anti-nukes. Specifically, weapons resistant plutonium can be made by increasing the proportion of Pu-240 and by adding a little neptunium - of which we have plenty - to the mix to generate Pu-238.

We have many thousands of reactor-years of PWR and BWR experience, and almost all have performed admirably, some loaded with MOX. Thus there is no good reason to reject the experience, simply because MSR's are sexy - although I concede that MSR's are sexy.

I believe in MSR's, and I believe in the importance of generating U-233, but, that said, we do not have thousands of reactor-years of experience with them.

But I do not believe in enrichment plants. They are wasteful. They have been more trouble than they are worth. I would abandon U-235 as a fuel, if the choice were left to me, except where it is created by capture in U-234 that was, itself, created by capture in U-233.


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PostPosted: Nov 23, 2009 12:13 am 
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jaro wrote:
dezakin wrote:
Seriously, if Rossing with 300ppm hard rock ores can turn a profit after the uranium price crashed with only the infrastructure of Namibia, India is simply doing it wrong.

In fact Rossing was considering closing the mine after the uranium price crashed. They were losing money. You MUST know that.
How do labour and federal tax levies in Namibia compare to other places ?

At the outlier for utilizing the lowest of ore grades during the hard times, because of a flood of fissile material from cold war stockpiles. My point is if India found fissile material of strategic importance they could do it far more efficiently than breeding. Now perhaps Pu-239 itself is of strategic importance, you know, with Pakistan being such a bother...

Breeding will never be desirable for any resource constraints on its own however.


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PostPosted: Nov 23, 2009 2:47 am 
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NNadir wrote:
Lars:

I can't see one good reason, from an external cost standpoint, for mining more uranium and going through the dubious process of isotope separation - the only nuclear power technology that is inherently dual use, weapons and power - creating even more so called "depleted uranium," and this in the form of UF6.

It is not wise in my view to mine uranium.

There are physics differences between plutonium and U-233, of course, particularly with delayed neutrons, but the fact is that there are many nuclear reactors around the world that operate on MOX and do so quite well - these challenges have demonstrably been met.

The situation with respect to U-238 and Th-232 are analogous: Both are just one neutron away from fissile nuclei. Both are present with large inventories in already mined material. Both have been considered "waste products" although the thorium waste product largely derives from the former use of lanthanides in television tubes.

Done right, both are proliferation resistant, in spite of the blather to the contrary by anti-nukes. Specifically, weapons resistant plutonium can be made by increasing the proportion of Pu-240 and by adding a little neptunium - of which we have plenty - to the mix to generate Pu-238.

We have many thousands of reactor-years of PWR and BWR experience, and almost all have performed admirably, some loaded with MOX. Thus there is no good reason to reject the experience, simply because MSR's are sexy - although I concede that MSR's are sexy.

I believe in MSR's, and I believe in the importance of generating U-233, but, that said, we do not have thousands of reactor-years of experience with them.

But I do not believe in enrichment plants. They are wasteful. They have been more trouble than they are worth. I would abandon U-235 as a fuel, if the choice were left to me, except where it is created by capture in U-234 that was, itself, created by capture in U-233.


1) I agree that enrichment is a proliferation risk. But in the earlier post I showed that even with a massive, supply the world's energy type rollout of MSR's we do not need to increase the existing capacity of enrichment. And with each plant we build we reduce the future demand for enrichment services.
Choosing to store the DU as UF6 is an economic decision based on the thought that a better enrichment technique (or high uranium prices) will render the UF6 valuable to use as feedstock again. It isn't a long term solution.

The rest of the response avoids the key issue: where do we get the fissile startup charge needed for 10,000 GWe of new nuclear capacity? By the way, the question is equally valid whether we are talking about LWR's, MSR's, and more important for fast reactors (HWR's get to avoid this question). As I see it there are two choices: mine it (u235) or make it (breeders). Breeders will make only a modest amount of new fissile per GWe-year. For a breeding LFTRs this is 100-200kg/GWe-year - worth roughly $3-6M/year minus whatever it costs to extract the generated fissile from the reactor and the additional security costs imposed by moving fissile around and the proliferation risks engendered by having the capability to bred surplus fissile. I'm not sure just how much a safe, breeding solid fuel reactor might generate but I'm thinking it is unlikely to be more than 400kg/GWe-yr.

This is a relatively small amount of money (and with the added costs for extraction and security it isn't clear to me that you make any money by using a breeder to make fissile). Even supposing the added costs for extraction and security are zero you have very little capital budget to work with. A nuclear reactor needs to generate a return on investment much greater than 10%/year. So if you sell $5M of fissile per year and it costs you nothing to extract it etc. your additional capital budget must be less than $50M. This is very unlikely for a fast breeder. It might happen for a LFTR but also seems unlikely. So, my conclusion is that startup on u235 will be the dominate form. While I don't particularly like mining of any sort, the mining required to start a LFTR on u235 is minor compared to the society benefit generated.


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PostPosted: Nov 23, 2009 7:04 pm 
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For various reasons given by different members, thermal cycle will lead to peak uranium. Fast breeders will result to a virtually inexhaustible source of energy from uranium already mined and from easily mined thorium in which case ores/wastes with 1-10% thorium are still available.
As regards slow build up of fissile stocks, theoretically the breeding ratios of 1.3-1.7 are possible. It is time to change over to such designs that make it possible. Indians are already trying to develop a metallic fuel.
MSR (Chlorides) is one option. There would be others.


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PostPosted: Nov 24, 2009 1:59 am 
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Well Lars, here's how I see it:

We have huge inventories of U-235, on which the United States has been running for quite some time, much of it from old Soviet weapons stocks and weapons. Roughly, if I believe some of the anti-nuke sites you see around, the world has a stock of somewhere in the neighborhood of 1600 MT of plutonium, and growing. Only about 200-300 MT of this is weapons grade material.

One of the fun ways to achieve nuclear weapons reductions and disarmament is to make government plutonium a revenue source for sale. Hell, that’s precisely what the Russians did in the 1990’s.

The plutonium, as I see it, represents about 120 exajoules of thermal primary energy, more than a one year supply for all the energy from all sources now used in the United States, and just shy of 1/4 of the world demand for energy.

Right now we produce about 30 exajoules of primary thermal energy from nuclear energy.

The amount you speak of would represent about 300 exajoules, but it's not going to come on line over night, and as it does come on line, it will produce more plutonium even at a breeding ratio of less than one, so long as we keep some depleted uranium in the mix.

By judicious use of thorium in thermal systems we can in fact realize modest breeding even in existing types of reactors.

I have always liked the Radkowsky concept, assuming that one can really get high burn-ups over 100,000 MWD/MT without making the fuel fall apart.

This may be just one way of assuring fuel supplies. I also like the DUPIC/Thorium scheme being proposed in Korea, Canada and maybe a few other places, cf. Annal.Nucl.Ener.35.10.2008.1842-1848, Annal.Nucl.Ener.35.10.2008.1842-1848. This sort of approach makes used nuclear fuel into new fuel.

We have, in this country alone, 75,000 of used fuel alone. Were we to build 10 or 20 CANDUs, we could burn that stuff for a long time, maybe even longer with DUPIC/Thorium, Pu/thorium/DU or any variation therin.

All along the way we can accumulate U-233 and more plutonium in this scheme.

In the meantime we can build homogenous thermal reactors and homogeneous fast reactors of various types and chemistries. Having a hell of a lot of aged plutonium around, with plenty of Pu-240 and Pu-241 can make for a hell of a breeding party, and I’m not talking about a debutante ball in Sands Point.


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PostPosted: Nov 24, 2009 2:16 am 
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I agree that we should pull the actinides out of the spent fuel and use it as a starter charge in LFTRs. This is because burying the Pu is such a bad idea.
But I can't see building breeders if a break-even LFTR is available.
Cost estimates for preliminary designs are never very reliable but cost projects for LFTR are noticeably under LWR's and with plausible reasons.
Cost estimates for fast breeders are generally 20% higher than LWR's and may be considerably higher.

Fissile mined from the ground is cheaper than fissile produced in breeders and there is a sufficient supply of fissile in the ground.
I'm not sure how much Pu extracted from spent fuel will cost if it is processed in a more modern fashion. Technically, it seems like a challenge but quite feasible - but people get pretty funny about isolating plutonium so I'm not wanting to see us dependent on that. I'm happy to promote the elimination of both weapons grade and spent fuel actinides if the policy makers can decide that this is a good thing. But I would rather not have to fight that battle - so a startup plan using 20% LEU seems like a good baseline plan.


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