Uranium Is So Last Century — Enter Thorium, the New Green Nuke

[Wild Cobra]

It looks promising. The fact that uranium/plutonium reactors have been already retrofitted to run on thorium shows there's a path for progress. The major problem for a complete LFTR solution seems to be the materials that are used on the core. They would need to be much stronger than what's currently used as there's much more heat generated under that process.

It looks to me like this could be a good solution for nuclear power without the risk of nuclear weapon proliferation.

They run on partial thorium like cars today run on partial ethanol.

[ElNono]

[Removed irrelevant Sciences ramble]

Here is the natural decay process of thorium:



the propose to change it to this:

Correct

but also adding neutron bombardment to the U-233 to change it to Th-232 again.

Incorrect

Now I would like to know how they plan to direct the neutrons at just the U-233 and Th-232, without creating unwanted isotopes from the Th-233 and Pa-233. they are in a molten salt solution, where you cannot separate them.

Uh?

- You bombard the fluoride-salt fuel containing U-233 and Th-232 with neutrons.
- The U-233 nucleus fissions, releasing energy and neutrons, which in turn hit more U-233 and Th-232, thus creating the necessary chain reaction while at the same time leaving Th-233 as 'waste'
- The Th-233 is drained out as the process happens. It takes aprox 20 minutes for the Th-233 to decay into Pa-233. Plenty of time to make it outside of the core and into storage.
- The Pa-233 in storage decays into U-233 after aprox a month, which can be then mixed again with Th-232 into the fluoride-salt solution.

The naturally occurring Th-232 is the actual fuel of the reactor.

I can name problem after problem that would have to be solved. the concept of the breeder reactor isn't such a bad idea. The U-233 can be used to create power. However, the trick is to still get more energy out of it than you put in to start with. You still have to put in a great deal of energy to change the Th-232 to Th-233. Another issue that occurs as the isotopes decay is they don't decay 100% to a desired form. The Pa-233 not only changes to U-233, but also Pa-232 then U-232.

- The conversion of Th-232 to Th-233 is done for 'free' as part of the nuclear fission, by means of neutron absorption.
- The parasitic reactions that produces small amounts of U-232 impurity are well known, and does not prevent the system from working.

The theories have been out there for decades to make thorium work. Nobody has created one yet that produces more power than it takes to drive the process.

Believe in perpetual motion also by chance?

Who claimed anything remotely to that?
Or you're just ready to move the goalposts?

The idea here is to make nuclear power safer, cheaper, less waste and without the possibility of building weapons from the byproducts.

Did you read the linked articles?

[ElNono]

Ok, I found an image that helps explain their proposal. I forgot where it was when I made the last post:



Looks like a proposed perpetual motion machine to me, to get more energy out than put in.

You obviously don't know how to interpret the graph if that's how you see it...

See those green dots in the arrows? They mean something... let's see if you figure out what it is...

[Wild Cobra]

Look, I hope I'm wrong on this idea. If it works as advertised, it would be awesome. I just don't see it happening. If the process didn't start with requiring neutrons to change thorium 232 to thorium 233, then we wouldn't have to count neutrons. In the end, you need to produce more neutrons than you use to make it viable. These other hybrid reactors that work use U-235 as a constant neutron source. U-233 is synthetic. The process to make it uses energy. As I said, looks like they expect perpetual motion to me.

[Wild Cobra]

You obviously don't know how to interpret the graph if that's how you see it...

See those green dots in the arrows? They mean something... let's see if you figure out what it is...

How about reading my post before that one.

[ElNono]

Duh... No Sherlock.
Start counting the neutrons. Tell me if you see viability.

This is gold...
This is no hypothesis... this is actually working right now.

Let me ask you, where you don't see the 'viability'?

They run on partial thorium like cars today run on partial ethanol.

Exactly.

[Wild Cobra]

OK, I misspoke on the neutron to change the U-233 to Th-233. This neutron and more come from the U-233. We have a problem with our neutron count. We are losing more neutrons from the U-233 than we are using to convert the Th-232 to Th-233. the U-233 is depleting faster than it can be renewed without external neutron bombardment.

I would love it if you can show me I'm wrong.

[ElNono]

Look, I hope I'm wrong on this idea. If it works as advertised, it would be awesome. I just don't see it happening. If the process didn't start with requiring neutrons to change thorium 232 to thorium 233, then we wouldn't have to count neutrons. In the end, you need to produce more neutrons than you use to make it viable. These other hybrid reactors that work use U-235 as a constant neutron source. U-233 is synthetic. The process to make it uses energy. As I said, looks like they expect perpetual motion to me.

Production of neutrons to start a nuclear reaction is already tackled and solved by regular uranium/plutonium reactors (be it with particle accelerators or a plutonium core).
Again, the chain reaction is what generates the cascade of neutron generation. This is basic nuclear stuff, BTW.

How about reading my post before that one.

Your assumption that the process involved turning U-233 into Th-232 was wrong.

[Wild Cobra]

Production of neutrons to start a nuclear reaction is already tackled and solved by regular uranium/plutonium reactors (be it with particle accelerators or a plutonium core).
Again, the chain reaction is what generates the cascade of neutron generation. This is basic nuclear stuff, BTW.



Your assumption that the process involved turning U-233 into Th-232 was wrong.

That's fine. If I'm wrong about them changing the U-233 back to Th-232, so be it. I thought that was wrong anyway. There is still a neutron count problem.

[ElNono]

OK, I misspoke on the neutron to change the U-233 to Th-233. This neutron and more come from the U-233. We have a problem with our neutron count. We are losing more neutrons from the U-233 than we are using to convert the Th-232 to Th-233. the U-233 is depleting faster than it can be renewed without external neutron bombardment.

I would love it if you can show me I'm wrong.

U-233 releases about 2.6 neutrons per fission. Not all the remaining 1.6 is salvaged for breeding, but outside of Pu-239, you'll be hard pressed to find better fuel for breeding.

[ElNono]

Now that we dispelled the myth that there's a neutron count problem...

did you read the linked articles?

[Wild Cobra]

Now that we dispelled the myth that there's a neutron count problem...

did you read the linked articles?

OK, I have an issue with myself.

Every Th-232 that changes to Th-233 requires 1 neutron.

Each Th-233 eventually changes to U-232 or U-233.

Each U-x emit two neutrons. Nice trick getting 50% of them to target the thorium, but yes, I am technically wrong there. Don't know what I was thinking.

You still have the U-233 wanting to fissile out faster than it is replaced, by it's bombardment upon itself. Just how do we insure 50% of the neutrons strike the nuclei of the thorium? If we have less than 50%, the chain is broken.

As for reading the article. Yes, I did. I do remember them saying something about needing 2:1 neutrons, but forget if and how they fixed the issue.

[ElNono]

OK, I have an issue with myself.

Every Th-232 that changes to Th-233 requires 1 neutron.

Each Th-233 eventually changes to U-232 or U-233.

Each U-x emit two neutrons. Nice trick getting 50% of them to target the thorium, but yes, I am technically wrong there. Don't know what I was thinking.

You still have the U-233 wanting to fissile out faster than it is replaced, by it's bombardment upon itself. Just how do we insure 50% of the neutrons strike the nuclei of the thorium? If we have less than 50%, the chain is broken.

As for reading the article. Yes, I did. I do remember them saying something about needing 2:1 neutrons, but forget if and how they fixed the issue.

There's different approaches to breeding thermal reactors like this one. The LFTR model described in the article mentions mixing Th and U together into the fluoride-salt mixture, which makes the fuel actually liquid. Fluoride works because it can withstand the high temperatures of the cores. Once the fuel is in the core, you simply bombard it with neutrons ONCE to start the reaction. You end up with a chamber with a heck of a lot of heat, a lot of neutrons and a lot of Th-233 in the fluoride-salt liquid (which you drain). Controlling the reaction is different than a a non-breeding reactor though. Can't use the neutron-absorbing rods, you have to instead regulate the input of fuel into the core. You also have problems cooling, since you don't want to mess the Th-232 neutron absorption, so the material of the core needs to be a lot tougher and a good heat dissipation system is a must (and these are right now probably the biggest obstacles).
Other Thorium breeding reactors use a blanket system (this is what converted uranium reactors use). The core only holds the U-233, and the Th-232 is sitting outside of the core like a 'blanket' around it. Neutrons are allowed to reach the blanket area. So you only have fission in the center of the core producing heat and neutrons, which then get absorbed by the Thorium in the surrounding blanket. In this system, you can also use some plutonium as part of the fuel so you can generate excess neutrons (Pu-239 releases a little over 3 neutrons per fission)

Another thing which I think you have a misconception about, is that all the Th-232 you put in needs to be converted into Th-233. It doesn't. Even if some Th-232 gets stored as 'recyclable' fuel alongside the Th-233, only the Th-233 will decay to U-233 (and a very tiny amount of U-232 impurity) in the set time (about a month). But since you're then again mixing the U-233 with Th-232 in the fluoride-saline solution, it's not an impurity, it's actually welcome.

[MannyIsGod]

Smh