Re: Question for Daniel Lavigne (among others)

Fritz Schlunder wrote:
> 
> about breeder reactors ... 
> are they not a feasible technology 
> that could eventually free us of fossil fuels?
> 
> What are the opinions of other readers in this newsgroup?


Breeder reactors that are cooled with liquid sodium 
have an interesting, although rather unimportant, 
advantage over the water-cooled ones that do the bulk 
of today's carbon-emission-free electrical generation: 
iodine binds strongly to sodium, 
and sodium iodide is an involatile compound, 
much like the familiar sodium chloride.

So in sodium reactors the radio-iodine pathway 
to accidental exposure of plant neighbours 
has one more barrier, a very reliable one. 
A liquid metallic sodium surface, so to speak, 
never sleeps in its vigilant watch for halogen.

The scarce-uranium part of the story that justified 
breeder prototypes never made any sense. 
A US dollar buys ~40 grams of natural
uranium and in today's burner reactors, e.g. CANDU, 
with no reprocessing, that makes > 2 electrical megawatt-hours. 
The uranium mining cost is less than US$0.0005/kWh. 

Breeders, with reprocessing, can reduce that to US$0.000005/kWh 
but to date, at prototype scale, have increased total costs.

Raising the price offered for uranium mining 
to a penny or two per kWh 
would yield at least tens of gigatonnes of it. 
See "World Uranium Resources"*, Kenneth S. Deffeyes and
Ian D. MacGregor, Sci. Am. January 1980.
It shows on page 74 a plot of seawater
and other low-grade ores.
The bar for "Black Shales" is 30 billion tonnes
high and centred at 0.006 mass percent uranium.

So uranium scarcity cannot, for at least several thousand 
years, close down burner reactors like today's. 


--- Graham Cowan
http://www.eagle.ca/~gcowan/Paper_for_11th_CHC.doc --
fireproof fuel, real-car range, no emissions