Tuesday, March 22, 2011

Rare Earth Elements and Thorium Power.

97% of world market supplies of rare earth elements (REEs) come from China and look to become insecure in regard to meeting "green" energy targets, since exports of REEs are scheduled to be retained for Chinese energy projects. REEs are essential raw materials for the fabrication of high-performance magnets in hybrid cars and wind-turbines. Monazite sands contain around 45 - 48 % cerium, 24% lanthanum, 17% neodymium, 5% praseodymium, along with minor quantities of samarium, gadolinium and yttrium. Europium concentrations tend to be low, in the region of 0.05%, and very low concentrations of the heaviest lanthanides in monazite accord with the term "rare" earth for these elements, with correspondingly high prices. The thorium content of monazite is variable and can be as high as 20 - 30 %, although commercial monazite sands typically contain 6 - 12% thorium oxide. In view of the radioactive nature of thorium, a hazard is posed from waste produced in the processing of rare earth oxides, which contains it.

A controversial REE processing plant is to be built by the Australian based mining company Lynas in Malaysia where it is argued that environmental protection laws are less rigorous than in Australia. The plant is predicted to produce one third of global demand for REEs in two years, hence breaking the Chinese monopoly. It is intended to bury the thorium in concrete, but a better option would be to use the material as a nuclear fuel in place of uranium the price of which has recently risen above $100/pound, in coincidence with the price of crude oil which is now also above $100/barrel.

Now thorium cannot be used directly as a fuel but must first be bombarded with neutrons and "bred" into uranium-233 as the nuclear fuel using slow neutrons, thus avoiding the liquid sodium coolant of uranium-plutonium breeder reactors, and which has the following additional advantages. (1) Plutonium and uranium could still be consumed in a thorium reactor, but without the need to manufacture more” plutonium. (2) While uranium-235 and plutonium-239 can be shielded to avoid detection in a suitcase to use that cliche, uranium-233 could not, because it is always contaminated with uranium-232, a strong gamma-ray emitter, which is far less easily concealed as a bomb.There is the final matter of the exact means for obtaining energy from thorium, for example using very large accelerator driven systems (ADS). A more modest alternative is the "Liquid Fluoride Reactor" (LFR), which is described and discussed in considerable detail on the http://thoriumenergy.blogspot.com/ blog, and it appears likely that the LFR may provide the best means to achieve our future nuclear energy programme.

7 comments:

Anonymous said...

Seems Mr. Nocera's been busy lately:

http://blogs.discovermagazine.com/80beats/2011/03/28/scientists-create-worlds-1st-practical-artificial-leaf-10x-as-efficient-as-the-real-thing/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+80beats+%2880beats%29

Will this thing be useful?

Clarence

energybalance said...

Hi Clarence,

it's not "artificial photosynthesis" but a way of splitting water by this "leaf£" which is more properly named a "photocatalyst". It's interesting, and that he has got it working using cobalt and nickel.

There are indeed problems environmentally and otherwise of extracting these metals in the enormous quantities needed to make a hole in the energy demand wall that is coming our way. It doesn't immediately get round the peak oil problem - I wish people would understand this.

I'd need to see some detailed numbers to gauge how good this is really rather than the hype. I am presuming that bucket of water is full of these "leaves" not just one?

Regards,

Chris

Anonymous said...

Chris:

I like throwing things your way when I come across them as I think you are more qualified to speak about them then I am ( I have an undergrad biotech degree) as you are a PHD level chemist with many years of experience, also you tend to be fair in your assessment of them. I am glad this thing will soon be producing a small amount of power thanks to Tata, that should give us some "real world" data. I'll try to find some numbers for you in the next day or two based on preliminary releases.

Goodnight,

Clarence

Anonymous said...

Oh, by the way, I support Thorium power, though I think we've discussed it before. I have a blog on my list called "Energy from Thorium".

Sorry, if my post was off-topic to this thread, but I didn't really know where to put it and I wanted you to see it. So this post is partly to make up for that. See, now you have an on-topic post on your thread :)

Clarence

energybalance said...

Hi Clarence,

always good to hear from you, and yes, I do my best to answer questions/comments as best I can.

I got my Ph.D 25 years ago and have done all kinds of things since then. I became a full professor in my early thirties but decided to move on from academia and my involvement in the energy fields is in the past 5 - 6 years.

All the best,

Chris

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