>From a posted site (Michael Pollak) on CANDU):
It is also where the "catch" comes in. If you can enrich uranium enough to make reactor fuel, it isn't all that hard to enrich it even more to build a bomb. Thus, the americans don't want Iran to obtain enrichment technology...
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This I think is actually untrue. I think it's the other way around. Enriching ore for a reacter is much easier than enriching for a weapon.
(Caution, I might have this exactly backwards or just wrong). The point to measuring the inputs and outputs of uranium isotope separation is to calculate the amount of energy needed. This is what SWU (separatable Work Units) are for (efficiency, energy, or work)
I am trying to figure this out with another member off list. I think it works like this. It takes work to separate the isotopes and concentrate the remainder up to fuel grade 3.5 or 4.0%. That `work' is the physics sense of the word. It takes more and more work to enrich the concentration the further you proceed.
The problem of enrichment is not linear. It is a curve in which you want to approach a given percentage.
About the only analogy I can think of at the moment is trying to climb a ladder, versus trying to climb a wine glass stem. The former is roughtly a straight angle and represents the work `curve' to get to fuel grade. The other is a steeping curve for weapons grade. So it takes an increasing proporitional amount of `work' to get to weapons grade than it takes to get to weapons grade. (This is the part that I might have wrong. You'll have to wait and see or play with this calculator and figure it out for yourselves):
http://www.fas.org/cgi-bin/sep.pl
The problem the IAEA faces is that a light water reactor can be reconfigued to produce plutonium as a by-product and the fuel can be pulled out and the plutonium can be removed from the fuel with chemical extraction. I am trying to get my kid (ex-chem major at UCB) to figure out how difficult this extraction process might be. He read up on Hartfort and other facilities in his nuclear chem class ten years ago.
I think the CANDU reactors in Canada are reactors that can be reconfigued to produce plutonium as a by-product of uranium fisson following Fermi and Seaborg ideas.
CG