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The Russian offer would not be acceptable to a country that wanted nuclear power for strategic reasons: would you give Russia control of your fuel supply in that scenario? Where does Iran get it's uranium from?

The other part of your point is good. Who says that they are building bigger centrifuges? Are there no other reasons for building them?

by Colman (colman at eurotrib.com) on Fri Feb 17th, 2006 at 11:15:14 AM EST
[ Parent ]
Agreed. As far as I understand it, the Russian deal dealt in yellowcake - which can also be used for civilian (nuclear fission) purposes. But I did not plunge too deeply into the details on that one.

Who says that they are building bigger centrifuges? Are there no other reasons for building them?

IAEA has released very little substantial materials besides their resolutions on this matter, but the press officer has released tentative hints. We'll have to wait on the IAEA report early March to see what's left of this. Note that the press isn't helpful on the issue as the focus is on enrichment only. Never mind that there's a difference between civilian and military use. Yet now everything that links to enrichment is Bad. Chalk that one up to bad press reporting.

According to the opinion of people working at ECN Petten, one of the two locations in the Netherlands with nuclear technology, bigger centrifuges are only meant for nuclear weapons.

by Nomad (Bjinse) on Fri Feb 17th, 2006 at 12:09:58 PM EST
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Chalk that one up to bad press reporting.

Again?

by Colman (colman at eurotrib.com) on Fri Feb 17th, 2006 at 12:15:37 PM EST
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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 ]
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 ]
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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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
[ Parent ]
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
[ Parent ]
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 ]
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 ]
...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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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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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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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 ]
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
[ Parent ]
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 ]
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 ]
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 ]
From Le Monde:

Le début de l'enrichissement a été constaté mardi par une équipe d'inspecteurs de l'AIEA, qui s'est rendue sur le site pilote de Natanz, au sud-est de Téhéran. "Notre équipe a vu que les Iraniens avaient commencé à introduire de l'hexafluorure d'uranium (un gaz) dans des centrifugeuses non reliées en cascade", affirme cette source.

A team of IAEA inspectors, who went to the Natanz experimental site, noted Tuesday that enrichment had begun. "Our team saw that the Iranians had started to introduce uranium hexafluoride (a gas) into non-cascaded centrifuges", said this source.

Le fait que cette manipulation concerne des centrifugeuses isolées, et non reliées en cascade, signifie que l'Iran n'a pas commencé à procéder à un enrichissement d'uranium à grande échelle - procédure indispensable à la production des composantes d'une arme nucléaire, et chose pour laquelle l'Iran aurait encore besoin de plusieurs années, selon des experts. <snip>

The fact that this experiment concerns separate centrifuges, not linked in cascade, means that Iran has not started the process of large-scale uranium enrichment -- indispensable to production of nuclear weapon components, and a process which will take Iran several years, according to experts.

Une délégation iranienne est attendue le 20 février à Moscou pour de nouvelles négociations sur la proposition formulée par le Kremlin de faire enrichir en Russie tout l'uranium dont Téhéran aurait besoin pour un programme nucléaire civil. Les Européens et les Américains soutiennent cette initiative russe, qui n'a cependant, à ce jour, recueilli que des réactions en demi-teinte côté iranien.

An Iranian delegation is expected to be in Moscow on 20th February for fresh negociations on the Kremlin's offer to enrich all the uranium Tehran would need for a civil nuclear programme. The Europeans and the Americans support this Russian initiative, which has only received, up to now, half-hearted reactions from the Iranian side.

by afew (afew(a in a circle)eurotrib_dot_com) on Fri Feb 17th, 2006 at 02:03:54 PM EST
[ Parent ]

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