Tip:
Highlight text to annotate it
X
The idea of splitting matter and creating other particles, you're getting into a lot
of alchemical realms. Scientists as God territory that people, I think naturally are concerned about.
As a recent nuclear physics major in college, our current nuclear has a huge waste stream.
And I was appalled by it. Uri Gat of Oak Ridge taught me about molten salt reactors and that
reignited my passion in nuclear because to me, it solves the waste problem.
All you need is about 800 kilos of Thorium feed per year, you know, per gigawatt of electricity.
Out of that, you get 799.-something kilos of fission products. Well, the missing mass
turned into energy. E equals MC-squared. It turned it into energy.
800 kilograms of Thorium, you have 799 uh...
Point something...
Of fission products...
Of fission products.
You have some fissile nuclei. That means this is a nucleus that if you hit it with a neutron...
The nucleus begins to distend, and a piece comes off into smaller pieces about...
30 or 40 percent the original mass of the nucleus, and the larger fission product is
basically what was left over.
What this leads to a double-*** distribution in the masses of the fission products.
On this table, you see the smaller fission product highlighted in yellow, and then the
heavier fission product highlighted in green. Then there is this gap for a while where there
are things that simply are not made by fission. Tungsten, gold, mercury, none of those are
made by fission.
Then when you get to thallium, now you're getting to what's called the decay products.
These are not formed by fission. They're formed when you leave uranium and thorium, plutonium
alone for hundreds or thousands of years. They will decay into these products. Those
are shown in this chart in a pink color.
Then there is what's called the trans-uranics. That's what happens when the uranium absorbs
neutron and doesn't fission. It turns into plutonium and americium and curium and a few
others. Most of it's plutonium. The overwhelming majority of trans-uranics are plutonium.
You get a lot of different things from fission, but you don't get everything. That's significant.
It's not as if you're dumping the whole periodic table out when you make fission. You get certain
elements in a preponderance, and you get some very rarely and you get some not at all, from
instance. You can't make gold from fission.
When we first load nuclear fuel in a uranium-fueled reactor, it is entirely uranium and most of
that uranium 238.
As it burns down first of the year, two years then three years, you see the formation of
other things. These are the fission products as well as some of the trans-uranics.
The hatch at the bottom gives away the fact that most of the rod is still uranium-238.
The overwhelming majority is still this unburned uranium-238. Still most of that potential
energy remains to be exploited.
In fact, the only fraction that has been truly burned is the fraction that you see in those
light pastel colors. Those are the fission products. But the remainder of the material
is unrealized energy.
Xenon is the most common of the fission products.
Some of these fission products have a really, really big propensity to eat neutrons. They
call it a cross section. It's a term that we use to describe how probable is a reaction
going to be.
And here is xenon-135 cross section, relative to two nuclear fuels. See these little bitty
guys, so imagine we're playing darts or something and throwing them. Which ones are we gonna
hit? We're gonna hit the big red dot.
When xenon-135 forms from fission, it really wants to eat your neutron.
You split an atom, you get smaller atoms that can poison the fuel itself and kill fission.
Unless the poisons can come out of the fuel.
This becomes a problem for real nuclear reactors. This was one of the first reactors that was
ever built. This was the Hanford reactor. They turned it on and everything seemed to
be going, and after about a day or two of running it, all of a sudden the power went
[sound] and dropped. Like almost to zero.
And they left it alone and after about 12, 18 hours, all of a sudden it went [sound]
and it came back up, to power again and it held there. What? And pretty soon it goes
[sound] and it drops off again. And I'm going, this makes no sense, we're not doing anything!
The thing's like turning on and it's turning off. And it's turning on and it's turning
off.
Well what was going on was the reactor would turn on and xenon-135 would begin to build
up. And as it built up, it would start eating all those neutrons, right? And then went [sound]
and it would take the reactor back down again. And then after a while it would decay away.
And once it decayed away [sound] the reactor would come back on again.
So it was following this up and down effect. Just crazy. These guys didn't even know what
xenon-135 was. This was one of the first nuclear reactors ever built. This actually was a contributing
effect to the Chernobyl disaster, was the presence of xenon-135.
I have a friend I've made online who is a nuclear reactor operator and he's goes "I'm
always fighting Xenon in my reactor. That's like all we do as operators is try to deal
with this stuff." And it's really hard to deal with in solid fuel reactors.
Gases have a really hard time escaping from solids when you're trying to go in between
the atoms.
My name is Dr. Steven Boyd. I am a solid state chemist.
All of a sudden, there is an atom of xenon gas where there wasn't one. What did that
just do to the surrounding atoms that pushed them on a mesoscopic level? It cracks the
crystals.
The solid fuel will begin to swell and crack.
Having that trapped and having that the most abundant fission product in there is kind
of disastrous.
You begin to get this central void. This is actually a gap in the fuel.
Now, you have a structural integrity problem that's starting to break down. In my opinion,
that's not a good design.
Xenon is a gas.
What happens to gases in a liquid? They come right out of solution. We need to build nuclear
reactors that are based on liquid fuel, because liquid fuel is going to be a whole lot better
at doing a bunch of things.
What is easier? Running a liquid past a solid in order to transfer the heat or having the
fuel be a liquid and use that in and of itself.
I would argue that actually combining the two is easier. Sure, it's more chemistry,
but so what? I'm a chemist. There are lots and lots of chemists. A lot of them are a
hell of a lot smarter than I am. Go solve the problem.
There's a lot of good going to having fission in a solution. It's so controllable. Fission
solid form sucks. Solids are a ***. They're a pain to dissolve an acid. These fluorides
flow at moderately low temperatures, and they are just a piece of cake to process compared
to solid oxides.
There's no free lunch. There's no free lunch. There is always a cost-benefit analysis that
needs to be done, always. There's no such thing as a waste-free energy source. With
that waste, sits think carefully about that waste.
NASA uses xenon to throw out the back side of an ion engine. There is a spacecraft in
the asteroid belt now called Dawn, which is using xenon ion engines to propel itself extremely
efficiently. We used to joke at NASA that xenon was one of the few things worth launching
into space because it actually cost about as much as it cost to put up in space.
One man's waste is another man's treasure. If you come up with clever ways of utilizing
that waste, you could help a lot of people and you can monetize that waste. And you can
do it safely. You can do it, in some cases for very strategic reasons.
Molybdenum is another common fission product.
Molybdenum-99 will decay a technetium-99. A technetium-99 in turn is used in a variety
of different diagnostic procedures. How is your heart performing, also your bones, liver,
your lungs. It's really a remarkable diagnostic tool.
Our power reactors today make lots and lots of molybdenum, but it's not extractable. If
you want to get it out, you'd have to shut the reactor down, depressurize it, cool it,
extract the fuel, reprocess it. By the time you did that, the molybdenum's all gone. It's
only got a CC6 hour halfway. You can't do it fast enough.
Bismuth-213 could be connected to an antibody. These antibodies can be tailored to go and
hunt down specific cells, in this case, cancer cells. Bismuth only has a half life of 45
minutes. It's very radioactive, and it's going away quickly. In that time, that antibody
can go and find a cancer cell.
I got bismuth connected to the bismuth decays, and alpha particle goes through the cell,
and it kills the cancer cell.
I sometimes even lay in bed thinking, "If my kid had leukemia, how hard would I be working
on getting this therapy ready for them?"
The radiation techniques we're using cancer therapy today, they're all based on beta-emitting
isotopes not on alpha-emitting isotopes. Betas, they have a big kill radius. They're not very
directible. It's OK, but it's really not a smart bomb.
You'll look at this, and you think, "There's got to be good alpha emitters." Turns out
there's not. Bismuth-213, which is the favored one, exists on a decay chain that no longer
exists in nature than altunium decay chain.
It's hard to get the right kind, the right chemical one that will lock onto the right
thing that's close enough to being stable that even after decays, it doesn't just decay
10 more times in the body. Bismuth-213 is one decay away from being done, and that's
what you want. You want one that's just on its very last decay.
We, in the course of pursuing a thorium-powered world, we created this decay chain about 50
years ago.
People have known about it for a long time. Look at the time on this report. March 2001.
Actinium and bismuth-213 are currently extracted from purified thorium-229. The only practical
way is to get this from the natural decay of thorium-229. It's very potent. We only
need on the order of a billionth of a gram to treat a patient.
It's especially good against dispersed cancers like leukemia, cancer of the blood, not tumorous
cancers where there's a big hard lump, stuff that's hard to get to, pancreatic cancer.
You get pancreatic cancer, you're probably looking at a death sentence.
We can do both at the same time. We can make electrical power, and we can make this useful
medical isotope.
We need to get this stuff in the hands of doctors to treat deadly diseases like acute
myeloid leukemia and other cancers. If we had this material, I really think it would
lead to a revolution in fighting cancer.
In reactors today, there's basically two categories of the waste. There's the fission-product
waste then there's the trans-uranic waste.
That's what happens when the uranium absorbs the neutron it does in fission.
Plutonium and the americium, the Curium. By using the thorium cycle and using it efficiently,
we can eliminate that category, the production of trans-uranics. We can just about eliminate
that so we're not making that in the first place. We are still making the fission products,
and a number of those I mentioned can be extracted usefully.
By extracting the first four fission products, xenon, neodymium, zirconium and molybdenum...
Right away, you've reduced the waste stream considerably.
What about the rest? The true troublemakers are strontium and cesium. Strontium-90 has
a half life of 30 years. Cesium-137 has a half life of 30 years. Even those two could
have very useful applications. Strontium-90 could be fabricated into little heating modules.
Cesium-137 could be used to radiate food.
Food irradiation does not cause the food to become radioactive. It doesn't happen. By
irradiating strawberries or lettuce or other leafy vegetables, you can kill E. coli, and
E. coli does kill people. In fact, it kills a lot of people each year.
Think of your home. Think of your pantry. Imagine taking everything out of your pantry
and pouring it on the floor. Your sugar and your cornflakes and your flour and your baked
beans and everything is in a big pile on the floor. How valuable is that giant mix to you?
It's not valuable at all.
It's worthless. It's completely worthless. All you'd do is you shovel it up and you throw
it in the trash. Now, you've had the same stuff you had a minute ago. Now, it's all
been mixed together. What makes the stuff in your pantry valuable is the fact that it
is separated. The sugars in one container and the flour's in another and your cornflakes
are in another altogether.
What we got with nuclear with nuclear waste is we got that pile of everything mixed together.
If we could partition it, we could put it back in its separate categories, we would
find it almost every one of those things as useful if isolated and separated from everything
else.
With about 30 different elements in the fission product distribution, not every one of those
will be worth extracting. If you apply this to 10, you would probably find you had some
very, very valuable materials coming out of that.
Right now, all mixed together, worthless, worthless and dangerous. Partitioned, they
could be very, very valuable.
[sound effects]
[background music]
The rods generate energy by transforming some of the uranium into different elements. Over
time, fission products start to build up. We need chemistry to separate them out. Since
the fission products are thoroughly mixed with the uranium...
Pyro processing...
A nifty technology invented by argon scientists.
See, they call it pyro processing, but it's a molten salt process. They're dissolving
this thing in a molten salt, and they're doing electrochemistry on it.
After chopping the fuel rods into small pieces, you submerge them in a vat of molten salts.
When you run an electric current through the vat, the uranium and trans-uranics, separate
out and forms crystals on the electrodes.
Molten salt can not only be a fuel, it's a way to reprocess or process nuclear fuels
and clean them up for reuse.
I looked carefully at so-called pyro processing. There are obvious improvements that can be
made with respect to the actual pyro processing techniques. We can do this in a much more
streamlined fashion.
The dirty metals and the dirty metal oxides that have been spent, if they were fluorinated
with some really safe fluorinating agent, it could turned into to liquid fluorides and
separated far easier.
On the other side of the coin is you're going to use thorium as your base load fuel, so
to speak, you have to have a kick start with uranium-235 that's still left over, the plutonium-239.
But hey, that is not a great way to get rid of these materials, because we've got all
this waste. Here in the United States, we've got 70,000 metric tons of this waste. That's
terrible.
For me, as an entrepreneur and a scientist, I know that I can save lives by using those
isotopes. I know that I can make money and better society with those isotopes.
Take some of the wastes that's really been created in our uranium-fuel reactors and potentially
destroy those long-lived trans-uranics through fission. Waiting them out to decay is a very
slow process. Plutonium-239, for instance, has a 24,000-year half life. That's a long
time you're going to be waiting for that to decay.
On the other hand, you can fission it, and then those fission products will decay very
rapidly, and you also get an energy release and a neutron release, which is -- both of
which are good.
You hate nuclear waste, so do I. These reactors can eat nuclear waste.
The United States has no plans to recycle the valuable platting or all that uranium
that's in those used nuclear pellets.
70,000 tons of American nuclear waste. You're going to need, let's say, a ton to run an
experimental molten salt reactor, a ton of fissile fuel. If the reactor works, we've
opened a door to remediating all nuclear waste. If the reactor doesn't work, we've added one
ton to a 70,000-ton pile to see, if we can re-mediate all of it on the whole planet forever.
We hate nuclear waste too, but what we really hate is we hate wasting it.