Article

2005-06-02 China-Japan-Koreas

U.S. Intel: Plutonium sent by Norks this year makes Iran direct threat

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Posted by Alaska Paul 2005-06-02 00:00|| || Front Page|| [5 views since 2007-05-07] Top

#1 Would like to see verification before I start jumping up and down like an organ grider's monkey, but my surprise meter would register 0 if true.

Posted by mmurray821 2005-06-02 00:09|| 2005-06-02 00:09|| Front Page Top

#2 I am a little curious as to why everyone seems to be pursuing the enriched uranium bomb when plutonium weapons seem more appropriate for missile launch. Is there something significantly more difficult about creating a plutonium device?

Posted by DO 2005-06-02 00:48|| 2005-06-02 00:48|| Front Page Top

#3 This would be very, very, very, very bad.

Bush's Iran strategy -- to punt -- would have totally failed.

Posted by someone 2005-06-02 00:49|| 2005-06-02 00:49|| Front Page Top

#4 yeah, no doubt Bush is as stunned as we are. Bush, is of course to blame, as the world is a much simpler place if you just blame Bush for all that is wrong in the world. It's deep....so deep...to do so.

Posted by 2b 2005-06-02 02:05|| 2005-06-02 02:05|| Front Page Top

#5 Do, although both types of bombs are technically difficult a plutonium bomb is more difficult than a uranium bomb and potentially more destructive. With a uranium bomb you need a critical mass basically devided in half. The two halves are then slammed together in a bomb to start the chain reaction that leads to an explosion. In a plutonium bomb a sphere of plutonium is incased in explosives that, when ignited, compress the plutonium. The result of pressing all those plutonium atoms so closely together breaks down their atomic structure thereby releasing the energy. Thats the short, simple explanation. You can then add tritium at the instant of explosion to greatly increase the explosive force. Much more technically difficult.

Posted by Deacon Blues">Deacon Blues 2005-06-02 07:14|| 2005-06-02 07:14|| Front Page Top

#6 See also BLOOMBERG.COM - the US claims it has intercepted 11 WMD shipments bound for North Korea and Iran over the past nine months. ARE YOU READY FOR A WAR!?

Posted by Glotle Flomons5456 2005-06-02 08:00|| 2005-06-02 08:00|| Front Page Top

#7 The rogue nations are going the enriched uranium route because they lack (for now) the facilities for plutonium. These facilities are also impossible to hide.

With the Uranium enrichment, they need a source of uranium ore and an enrichment facility containing a centrifuge cascade. This can be hidden underground.

For Plutonium, they needs a reactor, its Uranium fuel and additional facilities for reprocessing the spent fuel rods and separating the Plutonium.
The reactor is typically heavy water moderated and this requires large plants for the heavy water production.
If you go down the Plutonium route, you need complete fuel cycle technology, from ore to fuel reprocessing/vitrification.

Apart from (apartheid era) South Africa, nations have not gone for the simpler Uranium gun assembly type weapon.
The rogue nations have the same Chinese design. It uses Uranium but is a more sophisticated implosion type bomb.

Posted by john 2005-06-02 08:50|| 2005-06-02 08:50|| Front Page Top

#8 Uranium is essentially easier to obtain, and requires something analguous to the "shotgun" type device that was used in the Trinity test. Theres very little doubt such a device would work too. The problem with enriched uranium is that you need a pretty significant amount of it even these days to make a nuke, with plutonium you need I think as low as 2-5kg to make the warhead, although the implosion device involved is quite a bit more complicated and has tighter tolerances.

Posted by Valentine 2005-06-02 12:01|| 2005-06-02 12:01|| Front Page Top

#9 Trinity was a Plutonium bomb, that's the whole deal with a two stage device. Unless you have a long history with them you just gotta test.

Posted by Shipman 2005-06-02 12:30|| 2005-06-02 12:30|| Front Page Top

#10 Deacon Blues

No amount of pressure generated chemically can break atomic structure. Not even the pressures at the core of Earth. What you describe is what happens in neutron-stars.

Plutonium bombs work through the same principle than uranium bombs: neutrons splitting atoms who in turn deliver more neutrons. If you don't have critical mass neutrons escape from material at a higher rate than they create new neutrons. If you have critical mass then the creation of new neutrons exceeds the number of those who escape and the process begins to grow exponentially so you have a bomb.

Both in uranium and plutonium bombs explosives are there just to press tightly the subcritical masses into a critical one for the short time needed for the reaction starting.

Posted by JFM">JFM 2005-06-02 13:56|| 2005-06-02 13:56|| Front Page Top

#11 Trinity was a Plutonium bomb...

Right. They didn't even bother to test the uranium bomb. It was considered sure to work (and did).

You have to get the explosive "lens" for the plutonium bomb just right, or bits of it pre-detonate and you get a big, radioactive mess.

Unless you have a long history with them you just gotta test.

That's what I was thinking. Unless they have full, detailed blueprints from somewhere.

Posted by Angie Schultz 2005-06-02 14:10|| http://darkblogules.blogspot.com]">[http://darkblogules.blogspot.com] 2005-06-02 14:10|| Front Page Top

#12 JFM, that's what I meant, I just didn't say it right.

Posted by Deacon Blues">Deacon Blues 2005-06-02 16:02|| 2005-06-02 16:02|| Front Page Top

#13 An implosion type bomb can use Uranium 235, Uranium 233 or Plutonium 239.

Because of U232 isotope contamination, U233 is generally not used (one of the daughter nuclides is a hard gamma emitter).

A gun type bomb can use only Uranium.

U233 has similar critical mass to Pu239
U235 requires more material.
Actual amounts of fissile material required are dependent on the skill of the designers.

The Chinese designed weapon given to Pakistan and subsequently supplied to North Korea and Iran is an implosion type device.

The Pakistani attempts to purchase triggered spark gaps (used in medical lithotripters) show that their Uranium device is uses implosion lenses (they are using the spark gaps to trigger the lenses).
The plans discovered in Libya (sold to them by the Pakistani proliferation network run by AQ Khan) showed an implosion type weapon.

It may use Uranium but is not the crude gun design. It is second generation Chinese and designed to fit on top of a ballistic missile.

Posted by john 2005-06-02 16:16|| 2005-06-02 16:16|| Front Page Top

#14 "You have to get the explosive "lens" for the plutonium bomb just right, or bits of it pre-detonate and you get a big, radioactive mess."

This would suit their purpose just as well in their minds.

Posted by BrerRabbit 2005-06-02 16:17|| 2005-06-02 16:17|| Front Page Top

#15 Also, there is no need to test this design.
The Chinese have already done all the work.

Advances in computers have made much testing unneeded (especially for an unboosted fission weapon)
The presence of Pakistanis at one test at Chinese Lop Nor test range indicate that they probably tested a Pakistani assembled weapon in the 80's.

The 1998 Pak tests were done without any measuring equipment. They basically dug a tunnel, emplaced the weapon and set it off. There was no desire (or need) to obtain data. The test was a political act. The Paks probably lack the scientific talent to actually design (or modify) a nuclear weapon.
As this article points out
In the first 48 years Pakistani universities produced very few PhDs. In the last 50 years several hundred thousand students have graduated in various disciplines. However the output of PhDs from universities and research institutions remains very low. During the first 40 years, all the universities and research institutions in Pakistan produced only 128 PhDs in scientific disciplines. Of these 89 were produced in 1982-86.

Most of these PhDs were in chemical and biological sciences. Physics, a subject essential for developing a nuclear energy programme, has been a neglected science in Pakistan. In the first 40 years, Pakistani universities and research institutions produced less than a dozen PhDs in this field.

The Chinese had to provide detailed engineering drawings , with copius notes, to explain the fabrication of the weapon components.

Any North Korean or Iranian weapon will be a copy of the Pak suppied Chinese design. They will not need to test.

Posted by john 2005-06-02 16:29|| 2005-06-02 16:29|| Front Page Top

#16 AQ Khan Labs worked on a Uranium implsion bomb.
PAEC (Pakistan Atomic Energy Commission) under the late Munir Khan, using separate Chinese designs) worked with both Plutonium and Uranium. Munir Khan was in charge of the team that built Kahuta plant and cold tested the Pak bomb in 1983.

If the design passed to the Iranians is one using Plutonium, then a second proliferation channel exists (the AQ Khan network is the first).

Posted by john 2005-06-02 16:40|| 2005-06-02 16:40|| Front Page Top

#17 Thanks for the info. I wasn't aware a uranium design could be made small enough for the small to medium sized ballistic missiles these dopes have. I guess we now know which commentors are with, or might have been with, one of the National Labs. ;^)

Posted by DO 2005-06-02 17:02|| 2005-06-02 17:02|| Front Page Top

#18 You can use smaller amounts of Uranium 235 if your pit is a "composite" one that includes Plutonium 239.

I've read that after the Trinity test, it was suggested that the Uranium in the gun type weapon be instead fabricated into composite cores. This would have increased the number of bombs available. The proposal was rejected.

Posted by john 2005-06-02 17:38|| 2005-06-02 17:38|| Front Page Top

#19 Ah! Live and learn! Thanks John.

Posted by Shipman 2005-06-02 19:05|| 2005-06-02 19:05|| Front Page Top

#20 Here is relevant quote

Availability of additional bombs

It is very unlikely any more Little Boy-type bombs would have been used even if the war continued. Little Boy was very inefficient, and it required a large critical mass. If the U-235 were used in a Fat Man type bomb, the efficiency would have been increased by more than an order of magnitude. The smaller critical mass (15 kg) meant more bombs could be built. Oppenheimer suggested to Gen. Groves on July 19, 1945 (immediately after the Trinity test) that the U-235 from Little Boy be reworked into uranium/plutonium composite cores for making more implosion bombs (4 implosion bombs could be made from Little Boy's pit). Groves rejected the idea since it would delay combat use.

The improved composite core weapon was in full development at Los Alamos when the war ended. It combined two innovations: a composite pit containing both U-235 and Pu-239, and core levitation which allowed the imploding tamper to accelerate across an air gap before striking the pit, creating shock waves that propagated inward and outward simultaneously for more rapid and even compression.

The composite pit had several advantages over using the materials separately:

* A single design could be used employing both of the available weapon materials.
* Using U-235 with plutonium reduced the amount of plutonium and thus the neutron background, while requiring a smaller critical mass than U-235 alone.

The levitated pit design achieved greater compression densities. This permitted using 25% less than fissile material for the same yield, or a doubled yield with the same amount of material.

Posted by john 2005-06-02 19:44|| 2005-06-02 19:44|| Front Page Top

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