Letters to the Editor
Published Letters: 1824
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@ MD
[Read the article: ABC News' bizarre "scoop" on Iran's nuclear program]
[Read more letters about this article: Here]1,000 centrifuges, in line and operating efficiently (a "cascade"), are sufficent to produce enough weapons grade uranium for a single gun-style nuclear weapon (the type used on Hiroshima, but no longer utilized) PER YEAR. If Iran produced its first batch in 2009, it would be sometime in 2010 that a second batch would be available, and so forth.
While gun-type weapons are so reliable that they don't really need testing (the Hiroshima bomb was first "tested" in anger), it's not necessary to use a gun-type warhead with HEU (it is, with plutonium, because of the problems with pre-ignition). Better yields/efficiencies are achieved using implosion devices even with HEU, and the amount of fissile material requred are reduced. Thus, construction of an implosion device from HEU could be done in less time if the physics and engineering issues are resolved, and the limitation on speed to first bomb is in the acquisition of enough fissile material.
But the trade-off is that implosion devices are trickier to design and construct. But since the state of physics and engineering has improved markedly since 1945, the ability to get an implosion bomb right on the first try may be pretty easy (very few people have not managed to get one right the first time; the North Koreans perhaps the only exception).
Cheers,
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@ MD
[Read the article: ABC News' bizarre "scoop" on Iran's nuclear program]
[Read more letters about this article: Here]The nuclear weapons of the nuclear club, from the US on down (with the possible exeption of N Korea) are implosion devices, utilizing plutonium.
Not entirely true. HEU is used for some specialised weapons types, as are mixed HEU/Pu cores.
Cheers,
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@ NoahC
[Read the article: ABC News' bizarre "scoop" on Iran's nuclear program]
[Read more letters about this article: Here]The real way to go about producing your own nuclear weapons is with a heavy water reactor. It produces plutonium while producing power. Plutonium, being a totally different atom than Uranium, is relatively easy to reprocess....
Well, outside of its extreme toxicity (the most toxic element know to man), the fact that the irradiated fuel is extremely radioactive so you need remote processing facilities, and the fact that Pu spontaneously combusts.
... The kicker is that you can use naturally occurring uranium ore (Unprocessed!) to make this plutonium....
Not quite true. You can use natural uranium for the breeder material, but your reactor will be quite unwieldy if based only on natural uranium. Most breeders use enriched uranium.
... The only thing that you need is heavy water....
This helps as a moderator (that doesn't suck up neutrons), but there are other moderators available.
... Which, as any WWII buff can tell you, is not very difficult to make at all. Just electricity and water, and poof....
Not quite. Once again, you need to do isotopic separation (as opposed to chemical), just as you would for uranium isotopic enrichment. But you do have the advantage that deuterium is twice as heavy as hydrogen, so the difference in atomic weight between the isotopes is considerably greater for the hydrogen isotopes compared to the 1% difference in uranium.
Your reaction only needs a home and time, and you have yourself a plutonium bomb. Not only can you make it relatively easy, but you only need about 35 pounds.
Not quite that easy. See above.
FWIW, 20 pounds of Pu should be sufficient in a bomb (the critical mass in air is 10 kg., and implosion bombs use a subcritical sphere (at normal compression) and compress it considerably in the triggering process to make the resultant denser core with the same total mass supercritical.
Believe me, the HEU bomb is easier (and more fool-proof). But heavier. OTOH, while heavier, it's less detectable in transit (particularly since U-235 spectrum gammas are part of the natural background signal, and of lower intensity).
Cheers,
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@ NoahC
[Read the article: ABC News' bizarre "scoop" on Iran's nuclear program]
[Read more letters about this article: Here]Just for argument's sake:
D2O is most easily produced without centrifugation. All you have to do is electrolytically separate water. Heavy water is more difficult to split apart than is a regular water molecule.
All you need is some electricity and water. In world war II the Germans utilized hydroelectric plants to manufacture heavy water. All it takes is a steady source of electricity and enough water.
I didn't say centrifugation (nor was that the only method of isotopic enrichment for U-235).
Not sure electrolysis is a practical method (although it was used in Norway in WWII). See here:
http://www.fas.org/nuke/intro/nuke/heavy.htm
for more.
Cheers,
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@ NoahC
[Read the article: ABC News' bizarre "scoop" on Iran's nuclear program]
[Read more letters about this article: Here]There was a great PBS documentary on the Germans making heavy water at an plant in Norway called "Hitler's Sunken Secret." Worth a watch, if you can get your hands on it.
I've seen it. Being from Norway, and with parents that lived through the occupation, I've had an interest in that as well.
There was also the "Heroes of Telemark" which, being Hollywood, gussied up the story beyond repair. I've also read one account, complete with interviews of the survivors of the raid. It was tough to do the second attack (on the ferry); could have been many innocent civilian casualties. And in retrospect, it was prudent and necessary to take out the factory, even though -- given the lack of interest by Hitler -- the Germans wouldn't have gotten the bomb anyway. Far more justifiable than the U.S. attack on Iraq in a time of peace.
Cheers,
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@ Robert
[Read the article: If only Newt Gingrich were president]
[Read more letters about this article: Here]When all the neocons have is a hammer
every problem looks like a nail.
There might be some wags that would suggest that these people don't have a hammer ... and this accounts better for ther actions.
Cheers,
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@ shooter242
[Read the article: The people who claim "the surge is working"]
[Read more letters about this article: Here]There's certainly no partisan posturing here, thank goodness. LOL.
Glenn - It all reads like some caricatured cartoon of a country ruled by compulsive liars and two-bit cons -- like some college freshman's attempt to write a science fiction account of a country run by leaders who continuously manipulate the citizenry with the most unabashed, simplistic and transparent lies on the gravest of matters.
That's a dispassionate, clinical account. Why, do you dispute the accuracy?
Cheers,