Researchers discover conventional reactors burn their own waste when thorium is added

[wtmusic]

"Thorium mixed with plutonium and other actinide 'waste' could continuously power modified conventional reactors almost forever in a reusable fuel cycle, according to a discovery at the University of Cambridge in England.

The discovery, by PhD candidate Ben Lindley working under senior lecturer Geoff Parks, suggests that mixed thorium fuel would outperform mixed uranium fuel, which lasts only for one or two fuel cycles rather than for the “indefinite” duration of the thorium mix.

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By mixing thorium with 'waste' in a solid fuel, the nuclear industry could eliminate the need to bury long-lived plutonium and other actinides."

http://www.the-weinberg-foundation.org/2013/04/05/how-thorium-can-solve-the-nuclear-waste-problem-in-conventional-reactors/

"The idea of using thorium as a fuel source is not new; prototype reactors using thorium were operated in the United States in the 1960s. 'The reason why thorium was never seriously pursued as an alternative to uranium is believed to be because the uranium fuel cycle generates much more plutonium, which is the raw material used for nuclear weapons,' said Parks. In addition to its greater resistance to proliferation than uranium, thorium is also about four times more abundant."

http://www.eng.cam.ac.uk/news/stories/2012/safer_nuclear_future/

The thorium fuel cycle proposed for molten-salt reactors could be used in the world's 440 power reactors, with several advantages:

1) Complete burnup of long-lived actinides - nuclear waste would be less radioactive and "hot" for hundreds of years, instead of millions
2) Thorium is cheap and abundant
3) Safer, more stable reaction

[Warpy]

1. I was hoping thorium reactor research would turn something

completely unexpected up. I don't think anyone really anticipated this one.

If it can solve the most pressing problem with nuclear plants--the extremely toxic waste products--then nuclear power will have a future here. We just have to learn where to build them.

[kristopher]

9. I'm not seeing where it solves that problem

...the actinide waste could be safely recycled indefinitely

Previous claims about thorium have been wildly exaggerated by internet proponents, and I'd be careful of hype on this one also. If it is "recycling indefinitely" then it sounds like the process itself is a producing about the same quantity of actinide waste as it consumes.

I'd have to see some rigorous analysis of the full flow in the fuel cycle before believing this offers anything substantial.

Proponents claim that thorium fuel significantly reduces the volume, weight and long-term radiotoxicity of spent fuel. Using thorium in a nuclear reactor creates radioactive waste that proponents claim would only have to be isolated from the environment for 500 years, as opposed to the irradiated uranium-only fuel that remains dangerous for hundreds of thousands of years. This claim is wrong. The fission of thorium creates long-lived fission products like technetium-99 (half-life over 200,000 years). While the mix of fission products is somewhat different than with uranium fuel, the same range of fission products is created. With or without reprocessing, these fission products have to be disposed of in a geologic repository.

If the spent fuel is not reprocessed, thorium-232 is very-long lived (half-life:14 billion years) and its decay products will build up over time in the spent fuel. This will make the spent fuel quite radiotoxic, in addition to all the fission products in it. It should also be noted that inhalation of a unit of radioactivity of thorium-232 or thorium-228 (which is also present as a decay product of thorium-232) produces a far higher dose, especially to certain organs, than the inhalation of uranium containing the same amount of radioactivity. For instance, the bone surface dose from breathing the an amount (mass) of insoluble thorium is about 200 times that of breathing the same mass of uranium.

<snip>

Research and development of thorium fuel has been undertaken in Germany, India, Japan, Russia, the UK and the U.S. for more than half a century. Besides remote fuel fabrication and issues at the front end of the fuel cycle, thorium-U-233 breeder reactors produce fuel (“breed”) much more slowly than uranium-plutonium-239 breeders. This leads to technical complications. India is sometimes cited as the country that has successfully developed thorium fuel. In fact, India has been trying to develop a thorium breeder fuel cycle for decades but has not yet done so commercially.

One reason reprocessing thorium fuel cycles haven’t been successful is that uranium-232 (U-232) is created along with uranium-233. U-232, which has a half-life of about 70 years, is extremely radioactive and is therefore very dangerous in small quantities: a single small particle in a lung would exceed legal radiation standards for the general public. U-232 also has highly radioactive decay products. Therefore, fabricating fuel with U-233 is very expensive and difficult.

From factsheet on thorium: Thorium Fuel: No Panacea for Nuclear Power
By Arjun Makhijani and Michele Boyd

Full document can be downloaded here: http://www.ieer.org/pubs/

[Gregorian]

2. I'm giving this a rec without knowing much about this new mixing of fuels.

I know one thing, if population isn't going to stabilize for a number of years, and more people are wanting to live modern lifestyles (and who wouldn't since part of that means being healthy), then we've got to keep our minds open to all the possible energy conversion sources.

I still don't think we need to spend the money on this monumentally difficult nuclear scheme. The renewable ones seem to be cheaper to build. But I don't know what the lifetime of the fuel is for the Thorium reactors. It could be that the huge cooling facilities and other ancillary parts of these reactors are mortgaged down by the long term energy "production".

I don't know...

[zbdent]

8. Well, you do have to be careful.

Especially when you mix low-fat milk with pasteurized, and you dip your cookie into it. That shit blows up!

[phantom power]

3. interesting, the modification is using less water for neutron moderation

[wtmusic]

5. Seems like one of the big benefits is existing research reactors could be used to test it

by only modifying the fuel assemblies and the pellets inside them.

Having U-235/P-239 present only at the start would create a less-volatile sustained reaction. And less power, but the tradeoff is probably worth it.

Like trying to cook chicken on your grill using only lighter fluid, vs. charcoal ignited by lighter fluid.

[zbdent]

4. yes, but it gets tricky when Lokium enters the equation ...

[Mister Ed]

6. Heh. Good one.

[zbdent]

7. He's adopted.

Puny god ...

[RobertEarl]

10. I'm all for it

IF

"" Complete burnup of long-lived actinides - nuclear waste would be less radioactive and "hot" for hundreds of years, instead of millions""

And that is a mighty big IF.

But first thing we have to do is stop making more of the nuclear waste that is radioactive and hot for millions of years.

Indeed, how can anyone justify making more of something so deadly to our future generations? Really, how can any sane person support making more nuclear waste? How?

[hunter]

11. It reminds me of some of the CANDU waste burning proposals.

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