You CAN build a Nuclear Bomb using 2% or 20% enriched Uranium

[abduLMaria]

You CAN build a Nuclear Bomb using 2% or 20% enriched Uranium.

Chernobyl demonstrated the former.  It achieved a heating level of 1 million watts per pound, and had 400,000 pounds of Uranium, very slightly enriched to 2% Uranium.

At the peak of heating on the night of the Explosion, Chernobyl is considered by the science community to have reached a heating level of more than a 1/2 Terawatt, i.e. more than 500 Billion Watts.

Its normal heating for generating electricity was 3.2 Billion Watts.

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If you start studying Nuclear Science, you will find that "it's all about the probabilities".

When a Uranium 235 atom is approached by a Neutron from a Neighboring U235 atom, there is a much higher probability that the U235 atom will undergo fission, if the approaching Neutron is going "slow".  Which I admit is counter-intuitive, at first.

Slow for a Neutron is about 3000 feet per second.  When they are released by a U235 atom fissioning, the Neutrons have an energy of 10 MeV to 166 MeV, about 1/10 the speed of Light.  1/10 of 982 million feet per second.

The fast Neutrons have a low probability of interaction.  That's why nuclear reactors use Graphite and Water to slow down the Neutrons.  The Graphite & Water slow down the Neutrons, without stopping them (which heats up the Graphite and Water).

Boron is used to Capture the Neutrons, actually stopping them, to keep them from reaching a neighboring Uranium atom.  The Boron also heats up.

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So what is the trick to making a Nuclear Bomb with 20% Uranium ?

20% enriched means, it is 20% U235, vs. the 80% of typical weapons grade.

Part 1 of making it function as a bomb is, you have to increase the Probability that Neutrons will cause a Fission reaction in a neighboring U235 atom. By a factor of 4 - then you have just as many fission events, per pound of U235 - as the 80% U235.

This is not normally done, by the Jewish run countries that have Nuclear Bombs that utilize enriched Uranium.

They use the enriched Uranium, emitting Fast Neutrons, and surround them with solid Uranium metal.

Although there is a low probability of a Neighboring atom undergoing fission, because it is a "Target Rich environment", the fast Neutrons will still create Fission events.

Also, the Jewish run nations that have nuclear bombs - want to keep the technology all for themselves.

So all of us raised in those nations, are told that the way to build a nuclear bomb (using highly enriched Uranium) is to smash 2 separate pieces of U235 together, in the gun-type assembly that was used at Hiroshima.

Part 2 of making the lower-enriched Uranium function as a Nuclear bomb is, holding the assembly together while it heats up.

The bomb components tend to melt at 2600 F, the melting point of steel.

Yet the components of a Uranium (Hiroshima) type nuclear bomb heat up to 100,000+ degrees F.

The Uranium is heated far beyond its boiling point and becomes a Gas.  It is the Force & Pressure created by that expanding Gas, that gives a Nuclear Bomb its power.

The problem is, it is suspended in mid-air.  If it becomes liquid metal after 1 second but has only undergone a small fraction of its heating, it might still be a Big Mess, but it is not very useful militarily.

Telling your opponent that you are desperately trying to kill them, and then dropping a big radioactive mess on them, doesn't kill them but it does tend to upset them.


Part 3 - it's not trivial to have a Nuclear Bomb work the first time you test it.

In other words, a country that has Lower enriched Uranium that wants to test a composite assembly, has to do Nuclear Testing.  That tends to be detect-able, and then all the Jewish run nations that want to be the only countries with nuclear weapons, are notified of the bomb development process.


For reference I suggest 3 sources -
*  the HBO Movie "Chernobyl".  Especially the part where Jared Harris is explaining how Chernobyl became a Bomb, using simple red and blue pieces of printed plastic.  In English, of course.

It's actually one of the best movies I have ever seen.  I suspect the American CIA was involved, because SO MUCH MONEY was spent on set design and costumes and photo-realistic CGI.

*  Russian Nuclear Scientist Mikhael Malko's paper about Chernobyl.
https://www.rri.kyoto-u.ac.jp/NSRG/reports/kr79/kr79pdf/Malko1.pdf

*  The Semester Class at MIT that is taken by Sophomores majoring in Nuclear Science & Engineering.

https://ocw.mit.edu/courses/nuclear-engineering/22-01-introduction-to-nuclear-engineering-and-ionizing-radiation-fall-2016/lecture-videos/

Also very highly recommended.  I don't think NSE can be explained any better, to an academic audience.

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Getting back to Chernobyl.

The "Coup De Grace" explained by the Jared Harris character is that when the plant operators realized they had a BIG PROBLEM on their hands, they of course pushed the "AZ5" button.  The button that told the machine to insert all the Boron control rods back into the huge core of graphite and Uranium.

BUT the control rods were tipped with Graphite.

If you read the Malko paper, you will find that the individual Graphite blocks were 9.5 inches square, and that the stack was about 22 feet high. 

In the middle of the Graphite blocks, there was a 4.5 inch diameter hole.  The Fuel Assembly, a bundle of 19 tubes total, 18 of which had Uranium fuel pellets in them, occupied about 3 inch diameter.  The Boron control rods were about 1 1/4 inch diameter.  And that hole was also where the water flowed.

So the average path length of Graphite, for a Neutron leaving one Uranium atom, to strike a Uranium atom in a neighboring fuel assembly 9.5 inches away, was 5 inches.

What happened when the Control rods were re-inserted is that they got stuck, related to the reactor having already massively over-heated.

That meant the average path length for a Neutron, travelling through Graphite, increased from 5 inches, to 6 1/4 inches.
That meant the Neutrons were Additionally Slowed Down - at the top and bottom surfaces where the control rods were trying to re-insert.

The slower travelling neutrons had a significantly greater chance of causing a Fission event in whatever Uranium atom they struck.

And the rest became part of History.  But in the process of exploding, the Chernobyl reactor proved what may not have been obvious - that you can build a nuclear powered bomb using Low Enriched Uranium.