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Re: Thorium Remix 2009

Unread postPosted: Mon 18 Oct 2010, 02:26:23
by Dezakin
EnergyUnlimited wrote:
Dezakin wrote:They form equilibrium concentration because they form at low concentration. They're at worst annoying.
http://energyfromthorium.com/2010/06/20 ... n-poisons/

It is big annoyance.
Salt distillation would not be needed, if you don't have to remove neutron poisons other than Xe135.

There are other neutron poisons that form with much smaller cross sections yet aren't in equilibrium. If we could get rid of Samarium for instance then we have more neutrons to play with, which in thermal and epithermal spectra are always precious.
You can via brute force remove everything but the uranium using fluoride volatility of UF6 to my knowledge. I humbly bow to those more experienced in molten salt chemistry, but wasn't aware of any real showstopping problems with molten salt reprocessing. Things we'd like to do better sure.

I don't understand your argument.
Molten fluoride Thorium reactor converts Th232 into U233 (and a bit of U232).
Thorium doesn't form volatile hexafluoride like Uranium (and with some pain Plutonium) does.
Essentially you would isolate fissile isotope (and you may end up with excursion, if you try it in naive fashion).
However bulk of initial thorium input will still remain mixed with fission products (neutron poisons) and so you will have to dispose this thorium - antithesis of thorium breeder concept.

That's where some misunderstanding may be. In a two fluid breeder, there is no thorium in the core. You're probably thinking of one fluid designs (like the one prototyped at ORNL), which has much more complicated reprocessing. There's two separate fluids, the outer blanket which is thorium fluorides where the uranium is extracted by fluoride volatility, and the inner core which doesn't have any thorium in it.

The two fluid core and blanket design is my favorite for several reasons. First the reprocessing is much simpler of course. But the other is that in a two fluid design the outer vessel is insulated from most of the neutrons by the blanket, and so can be selected much more for its chemical compatibility with the salt rather than its resistance to neutron damage. I believe that you still have to be aware of different electrochemical potential between the core/blanket barrier and the outer vessel wall, but it does open up more options.

Another advantage is breeding doesn't explicitly require protactinium partitioning in a two fluid system, and so you can decide weather to do partitioning or pay for a larger salt volume.

The downside is the barrier between the core and blanket is in a hell of neutron radiation, and so there's some question on weather it will have to be replaced every so often.

Edit:

This is David Leblanc's exploration of the various molten salt reactor concepts, along with his modified geometry two fluid design for a full breakdown of the issues with liquid halide breeders. Its quite helpful, and I think you might enjoy it:

http://energyfromthorium.com/2007/08/23 ... t-breeder/

I'll forward your concern to the LFTR community forum relating to vacuum distillation material, as there are several chemists and nuclear engineers there with far more experience than I. I read something about tungsten being an appropriate tubing material

Would be nice if you let me know, what they think about it.

We have still some considerable problems with fabrication of bulk tungsten items (you will need long sections and significant diameters of tubing).
I don't know how relevant these can be though.

BTW,
Which forum do you have in mind?

Kirk Sorenson maintains a forum relating to liquid halide reactors:

http://www.energyfromthorium.com/forum/

There's some discussion of using tungsten tubing in this thread:

http://www.energyfromthorium.com/forum/ ... &sk=t&sd=a


There wasn't anyone pursuing liquid halide cooled reactors at this time besides the US, so there was no program to abandon. Much of the blame for abandoning this program lay at the feet of one Milt Shaw.

Indians are meddling with Thorium for quite a while.
It seems sensible to explore molten salts reactors in this context, but they didn't (please correct me if not true).

You may dismiss them, saying that Indians are stupid and don't know what to do, but I don't think it is that simple.
There may be more reasons...

I think that outside of the US, France, Britain, and the Soviets, the world has largely been following nuclear innovation rather than engaging it during the twentieth century. And yes, you could say I'm a bit disappointed in the strategic decision making of the Indians with regard to nuclear power. They should be willing to pay a 100% premium on uranium from their mines as a nonsignatory of the NPT, and recover it from the poorer ore grades in India, but they don't and uranium shortage in India is a worry.

Sure, this reactor is gaining awareness, but I think its going to take a large government investment to develop it, and that is at least a decade away.

I always wonder why it seems impossible for private corporations to invest these few $ billions?
This is not a lot for many firms.

I don't know about that. The timescales are awfully long for firms that want to see a return inside of a decade. I don't know what the solution is to encourage corporations to invest in very long term development. These large engineering challenges always seem to be driven by government. Maybe if everyone was forced to pay for the externalities of coal and natural gas...

Re: Thorium Remix 2009

Unread postPosted: Mon 18 Oct 2010, 15:21:13
by EnergyUnlimited
Dezakin,

Thanks for your remarks regarding two fluids breeder.
I was obviously thinking about original 1 fluid, ORNL like design.
I have to read more about 2 fluid design to be able to discuss it further.
It seems to be a way forward comparing to 1 fluid design.

I will also read contents of Kirk's forum to learn more about prospects of thorium technology and related engineering issues.
Incidentally I consider this technology to be one of very few options left for us to mitigate at least partially developing energy crisis.
I do not expect it to allow preservation of anything resembling status quo but it certainly can help to provide basic electricity supply for long, long time, perhaps indefinitely.

However from perspective of this site (PO.com) it is easy to argue that thorium technology may show to be only a talk.
Perhaps it is viable but we are not paying enough attention to it while we are still in position to develop it.
There are still many engineering but also political* issues surrounding it.
Once we are forced to pay attention, there may not be enough capital left to proceed and crumbling industrial infrastructure may shut down a window of opportunity for many decades or indefinitely.
So time will show but IMO this horse is certainly not dead.

*U233, if free of U232, is a good weapon fuel, perhaps the best one in mankind disposal.
Suitable for high but also a very low tech weapon assemblies, simple enough to be made in someones basement.
Low critical mass, relatively low radiotoxicity, low concentration of unwanted free neutrons within its bulk etc.

Re: Thorium Remix 2009

Unread postPosted: Wed 20 Oct 2010, 12:33:35
by Carlhole
PopSci: The Truth About Thorium and Nuclear Power

Thorium has nearly 200 times the energy content of uranium without creating plutonium—an ingredient for nuclear weapons. Is this the nuclear fuel of the future?

Talk of a large-scale U.S. nuclear renaissance in the post-Three Mile Island era has long been stalled by the high cost of new nuclear power plants, the challenges of safeguarding weapons-grade nuclear material, and the radioactive lifespan of much nuclear waste, which can extend far beyond 10,000 years. But a growing contingent of scientists believe an alternative nuclear reactor fuel—the radioactive metal called thorium—could help address these problems, paving the way for cheaper, safer nuclear power generation.

Three to four times more plentiful than uranium, today's most common nuclear fuel, thorium, packs a serious energetic punch: A single ton of it can generate as much energy as 200 tons of uranium, according to Nobel Prize-winning physicist Carlo Rubbia.

Re: Thorium Remix 2009

Unread postPosted: Wed 20 Oct 2010, 13:30:56
by EnergyUnlimited
Carlhole wrote:
Thorium has nearly 200 times the energy content of uranium without creating plutonium—an ingredient for nuclear weapons. Is this the nuclear fuel of the future?

At best it contains ~140 times as much energy.
If you include burned U238 and MOX from reprocessing, it will be less than that.
It is also creating U233, good weapon fuel.

Re: Thorium Remix 2009

Unread postPosted: Wed 20 Oct 2010, 19:17:25
by Dezakin
It can often be considered 200 times the energy in a liquid halide when considering the higher thermodynamic efficiency of higher temperature operation and losses in the once through cycle to enrichment tailings.

So a LWR would use about 200 times as much ore per GWe as a LFTR. Really its only a public communication argument in my opinion though, since uranium is plentiful enough and a small enough portion of the cost of nuclear energy that its not really an issue. The bigger wins in my opinion are lower fuel cycle costs, lower political costs, and most important, lower capital costs.

U233 is a terrible weapon fuel. Its got good neutronic properties, certainly, but the effort to produce it free of U232 is rather large. You have to run a very thermal spectrum to ensure low productivity, use full protactinium partitioning. Its simply easier to make Pu239 in research reactors than subverting a power reactor for weapons production. Perhaps a CANDU style reactor with online reloading could do it, but liquid halide reactors often have too hard a neutron spectrum to be appropriate.

Re: Liquid Fluoride Thorium Reactors

Unread postPosted: Wed 16 Feb 2011, 15:21:00
by Carlhole
China bets on thorium

China has committed itself to establishing an entirely new nuclear energy programme using thorium as a fuel, within 20 years. The LFTR (Liquid Fluoride Thorium Reactor) is a 4G reactor that uses liquid salt as both fuel and coolant. China uses the more general term TMSR (Thorium Molten-Salt Reactor).


[There's a good 15-minute introduction to LFTR, here. WARNING: contains technical terms and scientific concepts. Renewable energy supporters may wish to meditate before and after viewing.]

Re: Liquid Fluoride Thorium Reactors

Unread postPosted: Wed 16 Feb 2011, 23:45:55
by mos6507
That's probably the smartest single move China has made to be ready for doom. Not sure they'll beat the clock, though.

Re: Liquid Fluoride Thorium Reactors

Unread postPosted: Thu 17 Feb 2011, 00:35:34
by JRP3
There is an even more informative and easier to follow 25 minute version.
http://www.youtube.com/watch?v=EHdRJqi__Z8

Re: Liquid Fluoride Thorium Reactors

Unread postPosted: Tue 22 Feb 2011, 11:22:04
by Frank
Great link - thanks.

Re: Liquid Fluoride Thorium Reactors

Unread postPosted: Tue 01 Mar 2011, 02:29:32
by kildred590
As I understand it, Thorium does not change into Plutonium.
So its not economically viable, there's no "nuclear cycle", you can only use the rods once.

Re: Liquid Fluoride Thorium Reactors

Unread postPosted: Tue 01 Mar 2011, 10:20:10
by JRP3
You should probably do more research.

Miracle Energy source? Or Pie In the Sky?

Unread postPosted: Wed 02 Mar 2011, 16:30:42
by AirlinePilot
Debunk this...Im discussing this with some other pilots....

"The other ugly little fact is that for every unit of energy you get out of coal there's 13 more in the form of thorium in the fuel. Assuming you burn one or two of those equivalents getting the thorium out of the ash (nothing is free in the real world) that still means for every 1000MWe coal plant we can build 10 more fueled by the waste it ejects, or we can burn none of the coal for power at all and use it to produce synfuel instead off the process heat (in part, at least.) This is a nearly-ideal cycle as the optimum temperature for the Fischer-Tropsch reaction tops around 300C - and LTSRs have operating temperatures around 650C.

They therefore can provide direct process heat to drive this reaction and then turn a turbine for electrical power on top of it. Oh yeah, and the high temperature operation means air-based heat exchangers are practical for the power-generating side too (they're not for a PWR due to the significantly lower process temperature.) That means you can put them anywhere, not just where there are massive fresh water sources.

Mine the coal, extract the thorium, burn it, convert the coal to diesel and gasoline while generating electricity with the rest of the process heat. There's your energy solution - we have over 1,000 years of coal supply when used in this fashion in America.

We can be entirely energy-independent within 20 years.

But we have to eat the Greens first.

By the way, we knew how to do this in the 1960s. We built a reactor at Oak Ridge and Germany perfected the Fischer-Tropsch reactions for synfuel during WWII. There is absolutely nothing required in terms of big technology breakthroughs - that is, things we don't know how to handle and must discover - required to make this a reality.

With oil at $10/bbl it's not economically viable. With oil at $100, it sure as hell is. And doing it makes us PERMANENTLY independent of the towel-heads. They can EAT their oil; it's value to us drops to near-literal zero.

Re: Miracle Energy source? Or Pie In the Sky?

Unread postPosted: Wed 02 Mar 2011, 16:32:12
by AirlinePilot
When i say debunk..I mean it...tell me WHY!!! 8)

Re: Miracle Energy source? Or Pie In the Sky?

Unread postPosted: Wed 02 Mar 2011, 17:08:39
by Pops
I have no idea what you are talking about, but Rapier did a piece at TOD today about due diligence and his first question when looking at the latest miracle is:

At what scale has the process been actually demonstrated, and is the process currently running?


Since you say this miracle isn't new then surely there are these plants operating all over because oil hasn't been $10 for a while. I'd think China would be all over this...

Re: Miracle Energy source? Or Pie In the Sky?

Unread postPosted: Wed 02 Mar 2011, 17:32:27
by AirlinePilot
What Im talking about is the Thorium reactor..LSR uses coal ash as a source and we use the heat to generate CTL. We did do it long ago at oak Ridge and Im wondering why it isnt being done now. Im pretty sure I know, but Im very interested in others take on this and if others think it possible to replace a significant portion of our fuel usage with CTL all at the same time continuing to generate Electric with the Nukes and continuing coal fired plants.

I think its purely amatter of NIMBY's and the cost of infrastructure to enbale it. Its the old scope and scale issue too big and not enough to matter until oil is pirced in the HUNDREDS of dollars..but Im still interested in the actual viability of Liquid Sodium reactors presently.

Re: Miracle Energy source? Or Pie In the Sky?

Unread postPosted: Wed 02 Mar 2011, 18:29:21
by TheDude
Image

Two economists spot a $10 bill on the ground. One stoops to pick it up, and the other advises, “Don’t. If it were really $10, it wouldn’t be there anymore.”


Thorium reactors — The new free lunch | Energy Bulletin

The fast breeder reactor is only the second stage of a long-term project. “There are no defined time lines as lot of technology development, research and demonstration activities need to be completed before commercial deployment of thorium reactors for power,” Thakur told me in an email. “I think it is decades away.” First, he explains, “we need to have a significant capacity of the fast breeder reactors where thorium could be used as a blanket.” (For a good overview on what this means, read this article on thorium reactor physics at the World Nuclear Association.)


Rednecks aren't my first choice for useful information on tech, either. Try TED instead of Drudge/Digg/etc.

Re: Miracle Energy source? Or Pie In the Sky?

Unread postPosted: Wed 02 Mar 2011, 18:47:39
by Keith_McClary
Why don't the proponents of don't ask government or industry experts why it has been ignored or neglected. There are several countries with nuclear industries - surely some people would be happy to give their opinion. The implication is that either the industry people are stupid or there is a vast conspiracy to suppress it.

Same with other magic bullet wonder technologies we see hyped from time to time.

Re: Miracle Energy source? Or Pie In the Sky?

Unread postPosted: Wed 02 Mar 2011, 19:49:53
by Newfie
While I don't know the details of what you propose let's assume it is feasible at the moment. (It may well be.)

Then the issue becomes the political will of the masses to spend large sums on R&D to create a new industry to solve a problem which the public does not perceive. THAT I think is the problem, not technological, perception. Until we perceive that there is a threat we will not act. Individuals might, but not the populace in general.

While I believe that NIMBYS are at times a problem, and could be if production were to go forward, I think that the greater problem is our inability to take preventive action.

But, suppose you are successful, would it solve anything? Lets suppose that 40 years ago a bunch of scientist figured out how to increase the worlds food supply by 200%. Wouldn't that have been wonderful? Well....no. We just ate it up and increased population until we are where we are. The same goes for highways. Replace a two lane road with a four lane separated highway and what happens? Growth until the four lane highway is overcrowded.

Re: Miracle Energy source? Or Pie In the Sky?

Unread postPosted: Wed 02 Mar 2011, 20:43:40
by Ludi
NIMBYS are much less of a problem than lack of investors.

But NIMBYS are easier to blame - gotta hate on them greenies! :)

Re: Miracle Energy source? Or Pie In the Sky?

Unread postPosted: Wed 02 Mar 2011, 20:45:50
by lper100km
I just wish you had not included the descriptor of ‘miracle’ in the title. That’s an immediate turn off and sinks the idea before it gets any traction. Also, since miracle = pie in the sky, I think this proposal is double doomed.

There are no miraculous solutions, so don’t bother looking for one. If the science logic chain holds, this may be an idea worth exploring for its technical feasibility and economic utility.

So what is the basis for this? Is there any published science, or is this the distillation of high altitude cockpit conversations?