The truth is hiding in plain sight. It’s in the arithmetic of uranium enrichment.
The arithmetic shows that the Iranian nuclear program has already done more than 80 percent of the uranium enrichment work necessary to build three to four Hiroshima type atomic bombs.
First some background. A Hiroshima-type atomic bomb requires about 44 pounds of highly enriched uranium. Highly enriched uranium consists of 96 percent U-235 (the fissile isotope) and about 4 percent U-238 (the non-fissile one). By contrast, naturally occurring uranium contains only 0.6 percent U-235; the other 99-plus percent consists of U-238, which alone can’t sustain the chain reaction that’s essential for an atomic bomb, or even powering a nuclear reactor.
(The difference between U-235 and U-238 is that the latter has three more neutrons in its nucleus than the former. They are chemically identical, which is what makes them so hard to separate.)
Most of the uranium used in nuclear power plants contains only 3.6 percent U-235 and can’t be used to make a bomb.
Since highly enriched (bomb-grade) uranium contains more than 26 times as much U-235 as the slightly enriched (reactor grade) kind, people haven’t gotten too excited over the fact that Iran has been successfully enriching uranium to 3.6 percent for the past four years. Uranium enriched to 3.6 percent U-235 seems a long way away from the 96 percent U-235 bomb-grade stuff.
But it isn’t — as a bit of simple arithmetic shows.
Say you start with a ton of natural uranium. It contains 12 pounds of U-235 and 1,988 lbs of U-238. The way to produce enriched uranium from it is to get rid of most of the U-238. What’s left then contains proportionately more U-235 and is considered “enriched.”
Now consider the arithmetic of this process: To produce uranium enriched to 1.2 percent U-235 from a ton of natural uranium, you have to remove 1,000 lbs of U-238. To achieve 2.4 percent enrichment you have to remove another 500 lbs of U-238. Enrichment to 3.6 percent U-235 — reactor fuel grade — will require the removal of another 167 lbs, leaving 333 lbs of uranium enriched to 3.6 percent.
So the process of enriching some of the original ton of natural uranium to 3.6 percent U-235 involved removing 1,667 lbs of U-238 — or more than 80 percent of the original sample.
Recently Iran announced that it intends to further enrich its stash of 3.6 percent enriched uranium (Iran’s stash might be a little richer or a little leaner, but for simplicity assume it’s 3.6 percent) to 20 percent U-235. For the sample used in the foregoing example, that would require the removal of only an additional 273 lbs of U-238, leaving 60 lbs of uranium enriched to 20 percent U-235.
From there, reaching bomb grade would require removing fewer than 48 more lbs of U-238.
According to a story in the March 3 issue of the Washington Post, creating enough weapons-grade uranium to build a bomb from a stock of 20 percent enriched uranium would take about a month.
Uranium enrichment is a lot like launching a big multi-stage rocket: most of the energy is expended and most of the work is done by the first stage.
And the first stage — enrichment to reactor grade — is what the Iranians have already done.
So in terms of getting the necessary fissile material to build a bomb, they are already 80 percent of the way there.
According to a story in the Feb. 26 issue of The New York Times, quoting International Atomic Energy Agency inspectors, on Feb. 14 the Iranians moved 4,300 lbs of low-enriched uranium from their main enrichment facility to the smaller one (presumably the one near the holy city of Qom). That would be consistent with their announced intention of producing 20 percent enriched uranium; not nearly as many centrifuges will be needed to handle the 3.6 percent to 20 percent leap, because not nearly as much material needs to be processed.
The 4,300 lbs figure for the amount of uranium Iran has enriched to 3.6 percent U-235 should serve as a wake-up call in its own right. In order to get 4,300 lbs of reactor-grade uranium, the Iranians would have to have run nearly 13 tons of natural uranium through their centrifuges (or obtained several tons of reactor-grade uranium from somewhere like North Korea or Pakistan to supplement their own production). Either way, the 4,300 lbs contains nearly enough U-235 (154 lbs) for 3.5 Hiroshima-type bombs.
If the object of the Iranian nuclear program is to kill Israel and wake up the Hidden Imam — or pop one off in the realm of the Great Satan to really get the Final Countdown under way — they wouldn’t need many more than that.
And given Iranian President Mahmoud Ahmadinejad’s ongoing obsession with End-of-Days theology, together with the Islamic Republic’s ongoing infatuation with martyrdom, the foregoing possibility can’t be lightly dismissed. Basic human survival instincts can’t be taken as a given in the case of Iran.