REAL PLUTONIUM

Okay, now I'm going to talk to you about

plutonium

, so I once referred to uranium as the Boogyman of the periodic table, but if uranium is the Boogyman, then there is a Hannibal elector of the periodic table and he's a couple of places away. the right. and that element is

plutonium

. Plutonium has a

real

ly quite unpleasant reputation, for example there is a book here about the history of plutonium, the most dangerous element in the world. When the human race evolved, it evolved with uranium in the environment, so physiologically we can deal with it to some extent.

It is a man-made element, it was not in the environment when we evolved and this means that we essentially have zero tolerance for it, making it quite dangerous for us. We are in Cellfield, in the northwest of England. We are the only core laboratory where we are interested in plutonium because we need to be able to recover it from spent radiation irradiated nuclear fuel. You can't just use plutonium in a normal laboratory, you need to have a laboratory that is specifically designed. handling it so it's handled safely is at the point in the periodic table where it does interesting things, there aren't many elements you can tell when they were created, sometimes you can say it was discovered in 1869 or 19, whatever, but plutonium It was first made in 1940, the reason it was made is that it is a radioactive element and decays with a half life that depends on what particular isotope it is, if plutonium was created at some point during the formation of the system solar.

It all broke down long before scientists started looking for it on Earth. I once saw a piece of plutonium. I don't think I can tell you where I saw it, but it looks like a shiny piece of metal. What we're going to look at today is plutonium and solution and that's

real

ly interesting because plutonium has some very intense colors and the colors change depending on the oxidation state of the plutonium, plus it's incredibly dense as a metal. You could cut it with a hacksaw and the hacksaw blade would break before removing the plutonium from the Shiite density.

The Shiite density is demonstrated by the fact that a golf ball-sized piece of plutonium would easily weigh more than a kilogram, which is actually quite heavy, so the intention here is to recover the plutonium from the plutonium in spent nuclear fuel. is present at about 1%, what we do is use solvent extraction to remove the plutonium from the fission products in the aqueous phase and move the plutonium to a solvent phase and that solvent phase is a mixture of tribuphosphate and a diluent called kerosene without order here we have some plutonium nitrate and this plutonium is in oxidation state four and that is the oxidation state that can be extracted into triti phosphate.

I have two separate solutions here, both are plutonium nitrate, they are just in different concentrations it is dangerous for several different reasons it is dangerous because it is the basis of atomic bombs the second atomic bomb called Fat Man that was dropped on Nagasaki in 1945 contained plutonium and It was the plutonium that made it explode, it was a bigger bomb in terms of the size of the explosion than the first bomb that was dropped on Hiroshima, but plutonium is also dangerous because it is very poisonous. Many heavy metals are poisonous, in particular, say thallium, but plutonium is poisonous not only because of its chemistry but also because of its radioactivity.

Plutonium decays radioactively emitting alpha particles in the helium core and when that hits the cells in your body it can cause terrible damage and that can lead to cancer etc. I'm going to take a tablespoon of 30%. This is the solvent phase, as you can see. there it hasn't been mixed yet, the solvent is less dense than the area phase and resides on top of the areas, but you'll see in a minute that brown color will rise to the top phase according to this book. There is a club or there was a club in Los Alamos the bomb factory where they developed the chemistry of plutonium and they made the plutonium bomb of four people that had a rather strange name this says puu which means that your urine contains plutonium and these are people who Due to some type of accident they had plutonium in their body.

There was a person described as Margle who was working with a box of gloves like the ones we saw in the nnl laboratories and for some reason he had a needle and he stuck himself. He passed the needle through The finger of one of his gloves and he took out his hand and saw that there was a small black speck on his hand that was a fragment of plutonium and although doctors who tried to unearth this for the next 50 years, the plutonium was detected in his urine. . It wasn't a very high concentration. According to this, he had to provide a gallon of urine, which is 4 liters, before they could detect the plutonium, but he still survived fine, so I have two samples in there with plutonium nitrate on the bottom and tribuphosphate kerosene on the top part, so what I'm going to do now is put them in this device called a Vortex mixer, so as that mixes, the plutonium rises to the solvent phase, it will form a thrill and the solvent will start to come off the phase aqueous and the two phases will separate.

Plutonium is formed in the nuclear fuel of nuclear reactors. Uranium having an atomic number of 92 can be transformed into plutonium having an atomic number of 94 by absorbing neutrons. uranium absorbs neutrons, that is, uranium 238, the type of uranium that does not spontaneously catch and provides energy for the nuclear reactor. Hanford Washington's active material production facility for uranium 238, the most abundant isotope in natural uranium, becomes an entirely new fishable material. element known as plutonium 239, so it's the one called if you like the inactive uranium isotope, but it can absorb neutrons and transform into plutonium, okay, that should be it, that should be done now it seems like an emotion right now as you To stop.

We will see that the upper phase now has the color, the plutonium nitrate has now formed a chemical complex with tbp molecules and those tbp molecules have made the plutonium soluble in the organic phase in the AR reprocessing of radiated nuclear fuel. the fission products would now be in this lower phase the plutonium and uranium would be in this higher phase here so you've separated them the plutonium itself the metal is actually a very fascinating material. I've never seen it but it is meant to be very hard metal but it has a surprisingly large amount of allotropes and the allotrope is a different crystal structure.

Plutonium has six or perhaps seven different allotropes that differ in their hardness, mechanical properties, and even density, making the machining of plutonium necessary for the manufacture of nuclear weapons. bombs are extremely difficult, it also has a fairly low melting point, it melts at 639 degrees Celsius, which is actually a very low melting point for a heavy metal, for example osmium, which is not far off in the periodic table, it has a melting point well above 3000 degrees Celsius. Many of the um isotopes of plutonium are so radioactive that they are actually quite hot, so if you feel the sample, some of them may even glow red hot, but even the least radioactive ones apparently feel quite hot to the touch, although there are You have to be quite brave.

To touch them, what happens in a solvent extraction process is that the solvent is separated from the aqueous phase and then new aqueous liquor is added to that solvent to try to recover the plutonium. What we're going to do is remove, remove the Acoustic Liquor from this now from the bottom and replace it with some new liquor that contains a chemical that will promote the recovery of the plutonium from the solvent and remove the Acres phase from the bottom, of course , on an industrial scale. This is done with a variety of devices. Why are you trying to get plutonium just because it has to be disposed of in a special way or because you want to reuse it?

It's separated and in a pure form so it can be reused in things like MOX fuel, which stands for mixed oxide fuels, so that's where you combine the plutonium with the uranium and you can put it back into nuclear reactors and generate new energy. There is also an interesting feature that when they radioactively decay it emits these nuclei of helium atoms, so as you get an older and older sample of plutonium, the helium builds up in this crystalline structure, so although It looks like a piece of metal, it actually has helium atoms inside, like the fruit inside the cake and because of this crystalline structure, it tends to have crystallites with limits.

So-Cal grain boundaries between crystallites and helium can build up at the grain boundaries and weaken the metal quite substantially. Helium has two problems, obviously, in the short term if If you're someone who makes bombs, you have to be careful not to build up too much helium in the core of your bomb because it may not work properly here in sequence. The four Snapper explosions detonated at the top of its steel towers on May 7 and 25 and June 1 and 5, the second problem is that if you are storing plutonium that comes from reprocessed nuclear fuel Pro and is stored as waste until it's safe to be in the environment, you'll bury it somewhere. in the ground in a very strong container and when you design that container you have to take into account the fact that your metal will start to produce a gas as it decomposes and therefore your container has to be able to withstand the internal pressure to don't Don't suddenly explode food, which would be embarrassing if it weren't for you, your grandchildren, or your grandchildren when they suddenly discover that these safe containers have exploded.

Did you just describe the explosion of a container containing radioactive plutonium waste as shameful? Yes, shall I tell you? What Mark, for all the excitement about plutonium, it all seems pretty harmless there, that little muddy brown solution, well, it's highly toxic to radiation and you wouldn't want to drink that either, so I won't, although it does look a bit close. Coca-Cola to get the plutonium back into the aqueous phase, I'm going to use two different techniques, one is a reduction to bring the plutonium 4 to a plutonium 3 oxidation state, so what I'm going to do with this one is ADD, uh. a chemical called hydroxyamine nitrate.

This is another method where we are using a complexant, which means it forms a molecular chemical compound and the chemical we are using is called acetohydroxamic acid. When we have mixed everything, the plutonium will remain. at the bottom okay so this is the acetohydroxamic acid solution and now it is separating between the aqueous phase and the organic phase and as you can see the color in the top phase has completely disappeared now so the solvent is now free of plutonium and has returned to the aqueous phase and that aqueous phase can then be sent to subsequent plants for final purification and conversion to the final form which is plutonium dioxide, so, yes, this has not been so effective, but you can see the orange.

The color that was in the top half has been diluted now and most of the plutonium is in the bottom half as plutonium 3, so I have another story that I've told before, but it's a really good one and Brady wants to listen to it again, One of the people who taught me chemistry, a Cambridge professor, Alfie Madic, worked with plutonium during the Second World War and one night, when he was quite tired, he spilled the entire UK supply of plutonium, which was 10 mg, on the floor. table the bank he was working on was really upset because he had lost the entire country's supplies, so he took a saw and cut a hole in the top of the table, burned the wood and from the ashes of the wood he recovered 9 and 2 mg of the 10 mg he lost and would have hidden everything but by then he was so tired he didn't have the energy to repair the table so when the people came the next morning there was a big hole and then they found out what happened.

The one on the left here with the red solution is plutonium 4 with hydrohydroxamic acid. The one on the right here is plutonium. The blue plutonium at the bottom is plutonium 3 that has been reduced by hydroxyamine nitrate.