They took natural uranium, and they separated those two isotopes, highly enriched it in uranium 235.

Hardly at all. That's why it is still around. Uranium, two isotopes uranium 235, uranium 238 both of course are radioactive.

Because I think it'll fission. I think it'll fission just like uranium 235.

They'd take uranium 235 from less than one percent up to like 90 plus percent.

Now, let's say we were looking at uranium 235 as if it was its own thing.

You can see that uranium 235 is on par with the abundance of silver and platinum.

Uranium 235 on the other hand has a much shorter half life, seven hundred million years. OK.

You can see that uranium 235 is on par with silver and platinum. Can you imagine burning platinum for energy?

The bomb, called Little Boy, was the first atomic bomb ever used in warfare and utilized uranium 235 as fissile material.

We can make about 500 to 600 million in electricity and another 50 or 60 million on the fission of the uranium 235.

So really quickly they were going, OK, we can work with uranium 235, that seems OK, we can work with plutonium, that seems OK, but this uranium 233 stuff has bad news for making a nuclear weapon.

Yellowcake uranium, Mark.

It's less than one percent of uranium, it's about 0.7 percent uranium.

Uranium hexafluoride is a gas.

Uranium tetrafluoride is in solution.

He is not protecting himself from the uranium, he's protecting the uranium from himself.

And then we get to uranium.

It's going to stay in solution. But the uranium will come out as uranium hexafluoride, a gas.

And uranium 233 is being consumed but the neutrons from the fission are making new uranium 233.

It became uranium 233. Isn't that cool?

These lovely ladies are uranium fuel rods.

Large uranium reserves for nuclear fission still exist.

Uranium is used in the production of nuclear power.

Here's the decay chain that uranium 232 is on.

like uranium, plutonium, and everything else when they decay.

So, uranium, which is very big, wants to split.

You wouldn't happen to have any uranium on you?

You're fissioning uranium 233, but you're making a new one.

This is a handful of these uranium oxide fuel pellets.

You hit the salt with fluorine gas, and what'll happen is... There's uranium tetrafluoride, four fluoride ions, and there's uranium hexafluoride, six fluoride ions.

Now What about thorium and uranium? Both are naturally occurring materials.

The uranium and plutonium took on a gas form to escape.

Uranium 233, if you hit it with a neutron it will fission.

And with current reactor technology we really don't have very much uranium.

And you have the uranium mining that you have to deal with.

So they started looking at it, and it turns out, no, it's a really bad idea, because as you made the uranium 233, you were always making uranium 232.

Their major asset for developing nuclear weapons is the Natanz uranium enrichment facility.

It doesn't have anything to do, in specifics, with centrifuges, with uranium enrichment.

The radioactivities are mixture of Uranium and Plutonium used in Hiroshima and Nagasaki.

In reality, all our reactors today are burning uranium 235 which is like burning platinum, very, very, very rare. We didn't take either one of these paths ultimately. This was the great division in the beginning, was it going to thorium or is it going to be plutonium.

We could use thorium about 200 times more efficiently than we're using uranium now.

They say to me, We're going to run out of uranium. I said, OK.

You've got this core fluid, a lithium beryilium salt, with uranium tetrafluoride in there.

So now, you've just refueled your core salt with uranium tetrafluoride. Cool trick, huh?

India and Pakistan developed nuclear weapons secretly by enriching uranium in nuclear energy facilities.