Posted on 08/23/2008 4:36:48 PM PDT by decimon
Progress on South Africa's Pebble Bed Reactor Canada's SNC Lavalin has gotten a C$253 million contract to help build the second phase of a demonstration Pebble Bed Modular Reactor (PBMR) for completion by 2014 in Koeberg, South Africa. The small advanced reactor, a South African national project, would produce 165 MWe and could be built in 'packs' of eight. It is hoped that up to 30 of the units would be used in South Africa in coming decades, taking industrial heat-supply roles in the production of hydrogen and synthetic oils as well as electricity. The PBMR design is also a contender for build in the USA in the Next Generation Nuclear Plant project.
India's Thorium Reactor The head of the Mumbai reactor design and development group, Ratan Kumar Sinha, spoke to IEEE Spectrum about India's Thorium reactor design and plans. The Thorium reactor will have less waste (unburned fuel) than current reactors and is designed to operate for 100 years instead of 30-60 years for current reactors.
(Excerpt) Read more at nextbigfuture.com ...
What about thorium bombs?
Is this the next generation of terrorist dirty bombs?
http://www.candu.org/candu_reactors.html
We, the USA, should be shoulder deep in this work...
This will be a stranium on my cranium, but what the hey!
IIRC, thorium is not fissile - it can't be used for a bomb. As per the article, the thorium, in a reactor, will absorb neutrons to become U-233 but I don't believe U-233 is bomb material either. The U-233 would have to be somehow converted to U-238(?) to be suitable bomb material.
If I've botched that much then maybe someone will correct me.
I think we're doing some collaberative work with some other countries on thorium reactors.
Ping.
Sounds good. 'Natural uranium' seems much equivalent to thorium. Equivalent in a practical if not technical sense.
A thorium bomb is not possible because thorium will not fission. Thorium must fisrt be be converted to Uranium in a breeder reactor before it can be used in a reactor. Also the isotope of Uranium that Thorium is converted to is not useful as a bomb material because it does not easily fast fission.
Is this the next generation of terrorist dirty bombs?
First off thorium must pass through a breeder reactor to be converted to Uranium 233. The converted thorium will then need to be processed to be purified and processed in to new fuel.
At some point in that process if the irradiated fuel or the tailings of the reprocessing of the irradiated fuel were stolen they could be made in to a dirty bomb.
However the terrorist that planned such a project would have to be highly knowledgeable, very well equipped, spend many years of preparation and spend millions of dollars to equip a facility capable of building such a dirty bomb without killing everyone involved.
I would think that terrorist would rather spend their time and money on projects less dangerous to themselves and something less time consuming getting a bigger bang for the buck. I also believe that considering the size of such a project that it would be almost impossible to keep it a secret.
The thorium it self would be relatively benign as a dirty bomb as would the converted Uranium 233. Thorium and Uranium are toxic heavy metals but these material after being processed in to fuel are ceramics and not easily absorbed in the body. These materials are also not highly radioactive.
That would be U-235 that is useful for bombs and it can not be done. U-233 will fission upon absorbing another neutron.
So this is the quite possibly the next generation of nuclear power plants?
Without the waste disposal problem?
That would make all existing nuclear power plants practically obsolete (out of date) in the not too distant future?
The waste disposal problem would be the same. However reprocessing of fuel makes the volumes of fuel significantly less. But this is true for conventional Uranium fueled plants as well.
That doesn't seem to be the case with the described reactor. Unless the described fuels have been processed in a reactor.
From the article: "The fuel cluster has 54 pins arranged in three concentric rings around a central rod. The 24 pins in the outer ring have thorium-plutonium as fuel, and the 30 pins in the inner and middle rings have thorium-uranium-233 as fuel. The plutonium pins are placed in the outer ring to minimize the plutonium requirement. The thorium provides 60 percent of the reactor's power."
OTOH, I confess to be being baffled by descriptions like, "This is a vertical, pressure-tube-type, heavy-water-moderated, and boiling-light-water-cooled natural circulation reactor."
Okay then...U-235 is or can be derived of U-238?
Well that is what I get for not reading the entire article. I am partly wrong.
The reactor described in the article is in part a breeder reactor (as is a conventional Uranium Plant but this plant is designed to be more so than usual).
Much of the fuel in this reactor would be reprocessed fuel. The Uranium 233 and the Plutonium both would have to come from reprocessed fuel.
The Plutonium is there because it generates more neutrons during fission than the Uranium 233. Considering the amount of old nuclear weapons pits sitting around waiting for disposal I don’t know why they want to minimize the amount of Pu used in the reactor.
No.
U-238 can be converted (bred) in to Pu-239 the fissile isotope of Plutonium.
Thanks. You gotta be a real fissicist for this stuff. ;-)
Okay. Got my bombs backwards.
No problem. Glad to help.
Or schlep around the industry for long enough.
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