It is the site of the first nuclear reactor designed to make plutonium.

It started operation in 1943 in the middle of the Second World War.

The reactor is still there, though it's no longer operating.

I thought it was operating because there were three workers apparently working on it.

But then I realized that they were just models.

Brady thinks that's very funding.

So we're at Oak Ridge National Laboratory, and this is the site of the world's first continuously operated reactor.

You may recall that at Chicago, a pile of uranium and graphite led to the first measurement of criticality.

What happened here was the design and construction of the first purpose built reactor to run continuously.

There were three paths to a nuclear weapon.

One of them was involved involved the production of plutonium, which is an artificial element which must be produced in a nuclear reactor.

This reactor was built to demonstrate that process.

It was a project led by Fair me.

The design was principally done by Eugene Whitner, who was a Nobel Prize winner who lead researcher of the lab for a number of years and by Alvin Weinberg, who was the director of the lab for a number of years.

Exactly three days after here, Oshima B 29 set out for Nagasaki at 10.

58 the morning of August 9th, the bomb was exploded above the city and in the towering mushroom Japan could read its due.

This is the face of the reactor.

This is where the fuel lodge would be inserted after they were in the reactor for a sufficient length of time.

They were then pushed out the other end.

They dropped into a pool and were drug underwater to a chemical plant where the plutonium was extracted.

You can see the rod that's actually used to push the rod.

But inside many of those holes would be an aluminum rod that has within it pallets of humane.

It gets more and more rods go in.

What are we getting closer to him?

Well, you have neutrons flying around, and eventually what happens is that enough neutrons hit uranium fuel that you split enough, Adam.

Each Adam you split releases two neutrons, and now you start getting multiplication.

Criticality needs actually getting to that point where the multiplication is enough to sustain the reaction when you kick them out the other side, though it's not.

You haven't now go up, wrote a pure plutonium.

It's still work to be done.

You have, ah, log of a mixture of a lot of fission products uranium that hasn't transformed.

And so you have to chemically separate all that and that that is actually an art in itself.

And that was done in a building adjacent to this.

Uranium has two isotopes atoms with different numbers of neutrons.

In them.

There's uranium to 35 which is in quite small abundance, about 0.7% and uranium to 38 which is 99.3% abundant.

And this reactor worked on the decay of the uranium to 35 which generated the neutrons, which then tumble, did the target.

This is your favorite room, isn't it?

Well, you know, I didn't control it.

So this is the original control room.

This is where the reactor with controlled from this is obviously model number one of control rooms for reactors.

And it looks, you know, similar to what subject reactors from that error would have looked.

And so these various controls would tell you about power level and about radiation levels and the extent to its rods were inserted and things that relate to the operation of the systems, like the cooling systems.

This was leading to the production reactors which were to be built and were built in Hanford, Washington, for the actual production of kilogram quantities off plutonium.

Why is it called a graphite reactor?

Because you'd be talking to me about uranium and plutonium.

So the graphite is the moderator.

And so what you have to do is in the fission process, you get two neutrons off.

But the energy is wrong, and the graphite is one of the means by which you can reduce the energy to the range where you maximize the cross section for the next vision.

So this is actually the original logbook from the day when the reactor first went critical and family was actually here.

And he was called at five o'clock in the morning because the researchers knew it was going to go critical, and he came in and observed the first criticality of this reactor.

As a scientist, you Sophie's probably kept a few look books.

Do you look at that.

I feel a bit of excitement.

Well, you know, we all feel out lock logbooks, and we all have this hope that maybe our log book someday get this level of attention.

So it's actually quite exciting to be here and see this.

This is at the mid plain of the reactor, and that means that the neutrons that are coming out from the reactor going to come out horizontally.

And this is where the first neutron scattering measurement was done.

Now, to give a little background, we got three ways of looking at the nanoscale, or atomic scale properties of materials.

One is with the electron microscope.

One is with X rays, and one that is probably not as well known is with neutrons and the neutrons associated with this reactor, which operates at thermal energies.

These neutrons have wavelengths comparable to the distances between Adams and solids, so you actually can do diffraction experiments from solids, which Steve two different information than you would get with X rays.

At least information on magnetism.

It leads to information on the dynamics of the motions of off the atoms and the first neutrons guy.

Experiments were done here and that led to a Nobel Prize for Cliff Shoal, who developed neutron scattering in the forties and fifties.

At this laboratory, I kept on wondering why they still had this reactor.

They're my theory.

I have no idea if it's right is that the reactor is still so radioactive inside that it is easier to seal the outside and turn it into a museum than to work out how to decommission it before all the radio activity inside has dedicated way.

This is the birth of the nuclear error from the perspective off the scientific and technological application neutrons, and that has had a very important part.

And is the reason that Oak Ridge National Laboratory exists today because the fact that this reactor existed after the war and this capability existed and it was important for isotopes and it was important to the neutron scattering and it was important for materials, irradiation and the development of nuclear power is what led to the continuing off the scientific effort here for peaceful purposes, and that led to Oak Ridge National Laboratory.