Energy From Thorium Discussion Forum

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PostPosted: Mar 29, 2014 12:54 am 
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Kirk Sorensen wrote:
Zoom back and consider the victory these pieces represent.


As the famous saying goes first they ignore you...
They've gone past ignoring thorium now.

Kirk Sorensen wrote:
Except this time, he got thrashed for his poor argument in the comments section of the original Greenpeace article so soundly that I almost feel badly for the guy. On second thought, no I don't.


Made me smile. :D

As others have pointed out the radioactive waste diagram in the article is misleading, it assumes a once through fuel cycle. Even then I noticed something quite interesting on the chart, after about 500 years the radiation from the waste is 1% of where it started. Even at 200 years the waste produces 10% of the radiation that it started with, and drops rapidly from there.

No doubt 200 years is still a long time but that's nothing even close to the billion of years that they claim. At a billion years the waste has one millionth the radiation it started with, that has to be approaching the radioactivity of common dirt.

I've told people that a modern nuclear reactor actually reduces the radioactivity of the source material. No one believes me. Doesn't help that all they've been told their entire lives is that nuclear reactors produce piles of waste.

I've been telling people for years now, if it's radioactive then it's not waste, it's fuel.

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PostPosted: Mar 29, 2014 7:30 am 
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Maybe we just need a spacegun design like the Quicklauncher that can cheaply shoot up the waste into space.
500 tons per year of waste at 1000$/kg would cost half a billion but for the entire world.
Has anyone any numbers on todays costs for waste storage? Must be way more.

http://en.wikipedia.org/wiki/Quicklaunch


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PostPosted: Mar 29, 2014 9:41 am 
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Take it from an old space transportation guy---the last thing you want to do with nuclear waste is to try to shoot it into space---for so many reasons.

1. It's not really waste. If you can partition it almost everything in it is quite valuable.
2. Rockets don't always work, on a rate that would be absolutely unacceptable for nuclear waste transport.
3. The public would go insane if you ever suggested such a thing.
4. Where in space would you put it? Do you just want it floating around with an enormous amount of kinetic and potential energy, waiting to potentially re-engage the Earth at some future point, with enough stored energy (and I'm not even talking about the nuclear energy) to breach the casing and disperse radioactive material in the Earth's atmosphere.

Bad idea. Bad, bad, bad, bad idea.


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PostPosted: Mar 29, 2014 10:20 am 
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Wow! Wow! Wow!

I read the replies to the original Greenpeace article as linked by Mr. Sorensen. Wow! Or as they say where I come from Holy Wha!

Other than the Greenpeace shills, I saw no arguments on the pro side of the article. They ripped Jan a new one!

This was banging right at the back door of Greenpeace. It was their site. I think sooner or later one of these environmental groups is going to open a back door and let Thorium in. Judging from the response to that article, the momentum is no longer on their side.

Let's build one of these things and find the Achille's heel that way. If the heal needs a bandage, we'll just give it one.

It would be a fun project to work on.


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PostPosted: Mar 29, 2014 10:33 am 
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If you were going to dump the LLFPs in space, you would obviously not leave them into orbit for the reasons Kirk suggests, you would instead boost them into a Hohmann trajectory (or maybe Interplanetary Network) for Jupiter - timing it so they will slam into the Jovian atmosphere at tens of kilometres per second and will be completely burned up.

That is the lowest delta-v option that will not potentially cause problems for humans later. But even with a Falcon Heavy as a launch vehicle it is still more expensive than perpetual dry casks - maybe if they ever build a space elevator.


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PostPosted: Mar 29, 2014 11:41 am 
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E Ireland wrote:
If you were going to dump the LLFPs in space, you would obviously not leave them into orbit for the reasons Kirk suggests, you would instead boost them into a Hohmann trajectory (or maybe Interplanetary Network) for Jupiter - timing it so they will slam into the Jovian atmosphere at tens of kilometres per second and will be completely burned up.

That is the lowest delta-v option that will not potentially cause problems for humans later. But even with a Falcon Heavy as a launch vehicle it is still more expensive than perpetual dry casks - maybe if they ever build a space elevator.


The most practical trajectories to Jupiter involve multiple close Earth flybys. That would be absolutely unacceptable with nuclear waste. The interplanetary network you suggest takes an enormous amount of time to deliver a payload. Either strategy would require a robust spacecraft that could maneuver, make contact with Earth, maintain attitude control, and ensure payload integrity for many years.

Utterly, utterly, utterly impractical.


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PostPosted: Mar 29, 2014 1:11 pm 
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haha....yeah i had that thought already in mind,that it would fall down one day again and disperse in the atmosphere. yeah bad idea.
Just wanted to hear some opinion of some experts.


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PostPosted: Mar 30, 2014 12:08 am 
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E Ireland wrote:
If you were going to dump the LLFPs in space, you would obviously not leave them into orbit for the reasons Kirk suggests, you would instead boost them into a Hohmann trajectory (or maybe Interplanetary Network) for Jupiter - timing it so they will slam into the Jovian atmosphere at tens of kilometres per second and will be completely burned up.
Hey, If we put enough SNF into Jupiter and it reaches the gas core, might it turn Jupiter into a brown dwarf?

Quote:
That is the lowest delta-v option that will not potentially cause problems for humans later. But even with a Falcon Heavy as a launch vehicle it is still more expensive than perpetual dry casks - maybe if they ever build a space elevator.
A Kite-Launcher/HASTOL will do.

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PostPosted: Mar 30, 2014 1:15 am 
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Storage of LLFP on earth has a negligible risk, so you might as well discuss shooting bubble gum waste into Jupiter.

If we are going to do anything like this at all, it will likely be on the moon. Reprocessing and partitioning on the moon will be easy, as you don't have to worry about contamination inwards (like air or water ingress) or outwards (since the moon is completely sterile and isolated). Also high vacuum on the moon makes things like vacuum distillation easy. Getting to the moon is a darn sight easier than to Jupiter.

But we better hope that in the future, people will not be so utterly paranoid about radionuclides and recognize how tiny the risk is, rather than wasting huge amounts of materials and energy (the production of which involves considerably greater risk than any amount of radionuclide storage).


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PostPosted: Mar 30, 2014 1:55 am 
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If you want to throw away something from earth, why try Jupiter against solar gravity? The sun is a giant incinerator that can attract things thrown at it!


Last edited by jagdish on Mar 30, 2014 2:15 am, edited 1 time in total.

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PostPosted: Mar 30, 2014 2:14 am 
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The problem with thorium is that we want to go for the best straightaway. Start with spicing up the fuel with thorium for a high burn up in existing reactors.
http://dae.nic.in/writereaddata/.pdf_38
MSR is another good idea best started as a used fuel burner.


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PostPosted: Mar 30, 2014 11:21 am 
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jagdish wrote:
If you want to throw away something from earth, why try Jupiter against solar gravity? The sun is a giant incinerator that can attract things thrown at it!


That is a misconception, the delta-v requirement for dropping something into the sun from LEO is an order of magnitude greater than to putting it on a trajectory that takes into the Jovian atmosphere.


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PostPosted: Mar 30, 2014 11:23 am 
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cerebral wrote:
Maybe we just need a spacegun[/url]


This guy has derailed our productive thread. I am ashamed to see how well his plans have worked.

Back on topic!

The biggest reason in favor of thorium is liquid fuel. Is this correct?

Liquid thorium based fuel is low pressure, stable at high temperatures, and very very safe. This is the biggest reason for thorium right?


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PostPosted: Mar 30, 2014 11:25 am 
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Agreed, stick to the topic.


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PostPosted: Mar 30, 2014 12:44 pm 
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NicholasJanssen wrote:
The biggest reason in favor of thorium is liquid fuel. Is this correct?


That is what I thought. Most of the fission poisons would boil off the top where it could be collected and removed from the reactor. Sounds to me that this fact alone is enough to make LFTR viable. Additional continual processing of the fuel could remove other fission products that might poison the reaction. Even if all the non-gaseous fission products were not removed continually the use of liquid fuel would simplify batch processing, no? The decay of the short lived fission products would add to the power output of the reactor, so removing them may actually be detrimental.

Concerns over transuranic elements also sounds like a non-issue, leave them in the fuel until they fission. There may be a desire to remove the transuranics because they are especially valuable, like Pu-238. There may be a need to remove them because they are sucking up too many neutrons. It's my understanding that these transuranics would be effectively self enriching over time, that is the poison elements decay quicker than the fissile elements, allowing the material to be used for fuel in the future by only setting it aside. Is this true?

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