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Gnomemoot 0: Iran - what is the problem? | 194 comments (194 topical, editorial, 0 hidden)
Re: The Science Angle (4.00 / 2)
Actually, they don't need bigger centrifuges so much as they'd need more of them.  And technically, they don't need more, either.

My understanding of the process is that the difference between enriching uranium to a low level (for energy) and a high level (for weaponry) is simply a matter of scale -- if they are currently enriching uranium to a low level (which they claim that they are) the technology they already have can produce highly enriched uranium, it will just take a lot longer.

The attraction of bigger/more centrifuges is being able to get the uranium to that point faster.

by the stormy present (stormypresent aaaaaaat gmail etc) on Fri Feb 17th, 2006 at 12:23:55 PM EST
[ Parent ]
Re: The Science Angle (none / 0)
Thankyou! That was my understanding as well.

Obviously, it is possible to build a centrifuge that makes it extremely hard to reach weapons grade, but as I understood it, one of those is so hobbled as to make fuel grade hard to reach too...

by Metatone (metatone [a|t] gmail (dot) com) on Fri Feb 17th, 2006 at 12:37:16 PM EST
[ Parent ]
Re: The Science Angle (none / 0)
References anyone? This is surely a point of contention that can be cleared up by the power of Google. Or a chemist.
by Colman (colman at eurotrib.com) on Fri Feb 17th, 2006 at 12:38:27 PM EST
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Re: The Science Angle (4.00 / 2)
You need a physicist ;-)

The physical principle is to use the centrifugal force to produce an "exponential atmosphere" in order to separate the lighter from the heavier isotopes in gas form. The process of enrichment proceeds by multiplicative increments.

I can write something more detailed if I must.

Larger centrifuges are able to produce higher gradients, so a higher degree of enrichment is possible at each step.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman

by Carrie (migeru at eurotrib dot com) on Fri Feb 17th, 2006 at 12:53:05 PM EST
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Re: The Science Angle (none / 0)
Well, I would request more detail, if you are willing.

In particular can you comment on Nomad's assertion that there are centrifuges which are useful for fuel creation which are not useful for weapons creation?

by Metatone (metatone [a|t] gmail (dot) com) on Fri Feb 17th, 2006 at 01:34:25 PM EST
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Re: The Science Angle (none / 0)
I'll write more detail when I have time.

To a first approximation, the number of enrichment cycles it would take to reach a given level of enrichment increases as the log of the level of enrichment.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman

by Carrie (migeru at eurotrib dot com) on Fri Feb 17th, 2006 at 01:36:51 PM EST
[ Parent ]
Re: The Science Angle (none / 0)
On the engineering design side of the question I have little to say. Wikipedia says fuel grade is up to 5% enriched, but weapons grade is 20% (crude weapon) to 85% or more.

Wikipedia has a brief article about Gas centrifuges. I could try to answer questions about that.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman

by Carrie (migeru at eurotrib dot com) on Fri Feb 17th, 2006 at 01:42:56 PM EST
[ Parent ]
Wikipedia... (none / 0)
...has been lovely. I've been reading for a few hours this evening. Of course Francois pummeled me to the punch, but what gives.
by Nomad (Bjinse) on Fri Feb 17th, 2006 at 05:31:33 PM EST
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Re: The Science Angle (4.00 / 3)
Migeru,

In practice, the diameter of a centrifuge is limited by the structural strength of material and the dimensional control. The larger, the more stress at a given rotational speed and the harder to maintain geometry (and keep the rotor balanced).

The determining factor for the dimension of a centrifuge is not really the enrichment target but simply technical feasibility.
by Francois in Paris on Fri Feb 17th, 2006 at 02:01:49 PM EST
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Re: The Science Angle (none / 0)
BTW, have you seen any report on Iranian technical capabilities for metal work. Are they using aluminium or maraging steel?

by Francois in Paris on Fri Feb 17th, 2006 at 02:04:42 PM EST
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Re: The Science Angle (none / 0)
I have no idea.

How hard is it to work maraging steel anyway?

Remember I'm not an engineer.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman

by Carrie (migeru at eurotrib dot com) on Fri Feb 17th, 2006 at 03:56:17 PM EST
[ Parent ]
Re: The Science Angle (none / 0)
Well, the rumours are that maraging steel is an important smuggling item into Iran. But, I don't know how reliable the rumours are.
by Metatone (metatone [a|t] gmail (dot) com) on Fri Feb 17th, 2006 at 04:05:09 PM EST
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Re: The Science Angle (none / 0)
I do believe they are using maraging steel at least at the Natanz facility.

Bitsofnews.com Giving you the latest bits.
by Gjermund E Jansen (gjans1@hotmail.com) on Sat Feb 18th, 2006 at 02:43:17 AM EST
[ Parent ]
Re: The Science Angle (none / 0)
Well, at least some of them seems to be.....

Bitsofnews.com Giving you the latest bits.
by Gjermund E Jansen (gjans1@hotmail.com) on Sat Feb 18th, 2006 at 04:10:43 AM EST
[ Parent ]
Re: The Science Angle (none / 1)
You're right: it all comes down to a balance between how big the centrifuge is and how fast you can make it spin.

The key parameter is the centrifugal acceleration on the centrifuge's rim: this is proportional to the diameter of the centrifuge times the square of the rotation frequency... or the square of the speed at the rim divided by the diameter. In terms of structural stability, smaller is better.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman

by Carrie (migeru at eurotrib dot com) on Fri Feb 17th, 2006 at 03:54:06 PM EST
[ Parent ]

Gnomemoot 0: Iran - what is the problem? | 194 comments (194 topical, 0 editorial, 0 hidden)
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