Energy From Thorium Discussion Forum

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PostPosted: Nov 19, 2010 9:49 pm 
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I admit I don't know a lot about this topic. But, the designs I have seen so far are batch processes, not continuous. That is to say, Thorium is irradiated to become Uranium-233 over a period of around a month. But wouldn't it make sense to continuously extract the protactinium, then uranium, by chemical means so that unwanted isotopes aren't created, and there's no danger involved in moving the U-233 'by hand'? I see a LFTR as a chemical plant, with a thorium input, heat as an output, and various actinides as wastes (low level, right? we can burn that active stuff).

Are people playing in their basements trying this stuff? I remember David Hahn, the 'radioactive boyscout', making a real mess of it. I am impatient, waiting for Westinghouse et al to jump on the LFTR bandwagon. Maybe the Energy Club at MIT can start a little project ;)

Hahn had Americium, from smoke detectors, and Radium, from old clock face-plate paint, and Thorium, from lantern mantles. He had some other stuff too but I can't remember what it was. We can use a Fusor for a neutron source, but it's probably not so great. Maybe a nice neutron lens, aimed at a diffuse thermal neutron source.


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PostPosted: Nov 19, 2010 11:30 pm 
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RWKeyes wrote:
I admit I don't know a lot about this topic. But, the designs I have seen so far are batch processes, not continuous. That is to say, Thorium is irradiated to become Uranium-233 over a period of around a month.

Generally the designs are for continuous processes while the small scale early experiments tend to be batch oriented. The thorium gets irradiated continuously as part of the power generation process.
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But wouldn't it make sense to continuously extract the protactinium, then uranium, by chemical means so that unwanted isotopes aren't created, and there's no danger involved in moving the U-233 'by hand'? I see a LFTR as a chemical plant, with a thorium input, heat as an output, and various actinides as wastes (low level, right? we can burn that active stuff).

The general concept of molten salt reactors is a chemical plant rather than a mechanical plant. This is where the ideas began.
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Are people playing in their basements trying this stuff? I remember David Hahn, the 'radioactive boyscout', making a real mess of it. I am impatient, waiting for Westinghouse et al to jump on the LFTR bandwagon. Maybe the Energy Club at MIT can start a little project ;)

The little projects would tend to be non-radioactive experiments on some key steps of the process.
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Hahn had Americium, from smoke detectors, and Radium, from old clock face-plate paint, and Thorium, from lantern mantles. He had some other stuff too but I can't remember what it was. We can use a Fusor for a neutron source, but it's probably not so great. Maybe a nice neutron lens, aimed at a diffuse thermal neutron source.
And as I recall the authorities did not appreciate his efforts. Handling of radioactive material is not for playing in your basement. Even dealing with 700-1000C molten salt that contains beryllium requires special safety equipment etc.


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PostPosted: Nov 20, 2010 5:13 am 
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Regarding being a chemical process and continuous, let me expand on another aspect of this: designs seem to be based upon that of a traditional Brayton turbine to then produce electricity. I am wondering if the heat can be used more directly, in the production of useful chemicals where the process is highly endothermic. The production of ammonia fertiliser comes to mind, and also Fischer Tropsch for the production of hydrocarbon fuels. Perhaps there processes would be sufficiently power dense to make use of the heat without large amounts of piping and nuclear fuel/flibe.


Yea, I was kidding about going Hahn's route. He's crazy (still).


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PostPosted: Nov 20, 2010 11:18 am 
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I would hardly call a closed cycle Brayton turbine a traditional solution. In fact, it seems likely to me that it will not be used initially simply because it is not traditional enough! (Or more precise to reduce the R&D investment required to get the first machines running).

Using nuclear heat for high temperature industrial processes are often discussed and look like a promising future application. But the baseload electricity application is lower risk and big payoff so it will likely be the first target.

When industrial applications do get applied we will likely supply the heat in the form of a large pool of molten salt. Such a salt would not contain nuclear fuel and would not be flibe. This disconnects the industrial application from the nuclear plant.


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PostPosted: Nov 20, 2010 12:10 pm 
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Lars wrote:
I would hardly call a closed cycle Brayton turbine a traditional solution. In fact, it seems likely to me that it will not be used initially simply because it is not traditional enough! (Or more precise to reduce the R&D investment required to get the first machines running).

You're right, its not traditional. I guess what I meant to say is the idea of using thermal energy to mechanical work to electricity is different than the direct chemical reactor. My brother is an engineer who works with turbines, so perhaps I should ask him to explain the closed-cycle turbine in detail, and perhaps get on this forum.
Lars wrote:
Using nuclear heat for high temperature industrial processes are often discussed and look like a promising future application. But the baseload electricity application is lower risk and big payoff so it will likely be the first target.

Electricity is a very vesatile resource. My concern is the overall efficiency of going thermal to electric and back to thermal again, for processes which are done in large volume. But demand for ammonia, for instance, may not even be large enough to justify a dedicated reactor. Perhaps some valve and loop can be added to an LFTR so heat can be used for other than for electrical generation.
Lars wrote:

When industrial applications do get applied we will likely supply the heat in the form of a large pool of molten salt. Such a salt would not contain nuclear fuel and would not be flibe. This disconnects the industrial application from the nuclear plant.

After posting my previous message, I thought of how dangerous it would be to have hydrocarbon fuels and heat in close proximity to the LFTR core. A bad idea of mine. Yes, there would need to be a heat exchanger and a coolant pipe loop out a safe distance.

I am a bit embarrassed. I come here, with my ideas which are not even fully formed, never mind informed, and I don't really know much about the field. I apologize for being a clueless newbie. I am just excited about the possibilities of a nuclear renaissance via LFTR. I work in software and networking, and too often I feel like I am not doing real, productive work -- only making money (and sometimes not!). I am also a student, but my University doesn't offer any courses which seem like they could be of direct use towards making LFTR become reality (Which is a shame, because my University is considered by many to be the best in the world. Perhaps it's politics, as this place is the training ground for 'Liberals', who are supposed to hate nukes, or so I am told. Yes, I can take Intro Physics but that's about it. Maybe I'd do better if I were in the day school and not night school). Perhaps I should just stick to my area of expertise, take some of those old FORTRAN programs from the '60s that were posted, and rewrite them in a modern language (Java...no, I think Ada/Spark, the high integrity programming language) and make myself useful in that way.


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PostPosted: Nov 20, 2010 4:59 pm 
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Location: Idaho Falls, Idaho
Don't be afraid to speak your mind. You never know where a uniformed thought presented may, instill in the more knowledgeable a path to tread.


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PostPosted: Nov 20, 2010 5:16 pm 
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No problem. A question can often trigger productive thoughts.


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