This brown rock could power the world with electricity for decades to come, and with
zero emission. Yes, it is controversial, but it is true.
It’s estimated that United States could power its entire population with clean energy
for more than 1,000 years based on just its own reserves of this stuff.
But the US is not even the country with the most reserves, that would be India. But in
general it’s found in many places around the world.
So how does a rock power the planet? Well, it’s not the rock itself but the element
Thorium found within this rock. Einstein’s famous equation E=mc² states
that mass is equal to a lot of energy, and this rock has a lot of Thorium which can be
converted to energy via nuclear processes. Now you might say, but I thought nuclear power
was bad and dangerous. Well, it may have been in the past, particularly when a different
kind of nuclear fuel is used, but with Thorium, it can become far less dangerous.
How do we extract this near limitless amount of energy to solve our energy needs for the
foreseeable future? To understand this, let’s review how nuclear power plants work, and
how Thorium can change the game, and shift our paradigm about nuclear energy,
which in principle can be safe with little to no environmental impact. That’s coming
up right now...
People ask me how I choose my topics to make a video on. In today’s case, I was inspired
after watching two videos on Magellan TV, today’s sponsor called "Fukushima, Robots
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world of knowledge to gain that’s available at your fingertips. So be sure to click the link in
the description. I don’t think even Einstein could have imagined
the impact that his mass-energy equivalence principle would have on the world. It comes
from the theory of special relativity, which he postulated in 1905.
The principle is simple, when you split some heavier atoms into two lighter atoms, you
get a lot of energy. So for example, an isotope of Uranium referred
to as Uranium-235 or U-235 is a fissile material. If you hit it with a neutron at the right
speed, it will split into two lighter atoms like barium-141 and krypton-92 plus 3 neutrons.
These neutrons can then go on to hit other U-235 atoms which again can split into two
lighter atoms and some extra neutrons. In this way, it can lead to a continuous chain
reaction, producing more and more energy. Where does this energy come from? Well, if
we consider the mass of Uranium-235 plus the one neutron that hits it, we get 236.053 unified
atomic mass units. But now if add up the mass on right side of
the equation - the barium-141, krypton-92 and 3 neutrons we get an atomic mass of only
235.867. Where did the difference in the mass go?
This mass went exactly into Einstein’s equation, it became energy. Now the question is where
did this mass come from in the first place, so that it could be converted to energy?
As we discussed in a previous video about how the sun shines, it is all about the binding
energy related to the strong nuclear force. Binding energy in this case refers to the
energy needed to break the bonds between the protons and neutrons in the nucleus of an
atom. In other words, it takes a lot of energy to keep protons and neutrons so tightly bound
together in the nucleus. This comes from one of the fundamental forces
of the universe, called the strong nuclear force.
This force or energy that keeps the protons and neutrons bound together contributes to
the mass of the atom. So when the nucleus is split apart, some mass
is lost in the process as less energy is required to keep the nucleus bound together. This is
where the mass that’s converted to energy comes from.
Binding energy refers to the energy need to break the nuclear bonds. The more energy that
is needed to break the bonds of the nucleus of an atom, the higher the binding energy
of the atom. An atom with higher binding energy is more stable than an atom with lower binding
energy. You release energy when you go from lower
binding energy to higher binding energy. It’s the difference in binding energy that is released
in the nuclear fission process. Uranium has a lower binding energy than the
combined binding energies of Barium and Krypton. When Uranium splits, the overall binding energy
of the system increases. This means that krypton and Barium are in
a more stable and lower energy state than Uranium. And in going to this more stable
energy state, energy is released. But you might say, what can a difference of
0.186 atomic mass units make? The answer is a lot! It’s around 173 million electron
volts, or MeV. For comparison, when you burn paper or a
fossil fuel, each carbon atom consumed in the burning releases around 4 eV.
So the nuclear process with 173 million electron volts, releases about 40 million times more
energy per atom than burning fossil fuels like petrol or gasoline!
In general, 1 kilogram of Uranium-235 corresponds to about 2.7 million kilogram of coal equivalent,
depending on equipment and type of coal. It should be noted that U-235 can be split
into other atoms as well, such as Barium-144 and Krypton-90 plus 2 neutrons, which releases
even more energy, around 200 MeV. A nuclear powerplant works in many ways just
like a coal plant. You have some fuel you burn to heat water and turn it into steam.
Then you have steam turbine that then drives a generator which produces electricity. Then
the steam is condensed into water again and then re-heated, turned into steam and the
process continues. But the nuclear plant is radically different
to the coal plant in how it heats the water. In a coal plant you have a boiler heated by
burning coal which you constantly feed into the furnace.
A nuclear power plant is a more complicated and technologically advanced, but the concept
is still fairly simple. Inside the core you have fuel rods containing
your nuclear fuel. So, this could be Uranium containing U-235. Inside the fuel rods the
very energetic splitting of the uranium take place and thus energy is created in form of
heat. Around the fuel rods you have water that gets
turned into steam, and this steam is then going to the steam turbine, which drives the
generator to produce electricity. Now you might be wondering, how is the chain
reaction controlled so that this reactor does not become an atomic bomb?
The chain is controlled by control rods that temper how much heat the reactor produces.
To shut down a reactor the control rods are inserted fully into the reactor which can
cease the chain reaction. How do the control rods do that?
Control rods a made of a material that is very good at absorbing neutrons, so they end
up absorbing the extra neutrons that are being produced in the nuclear reaction that propagate the chain reaction.
So as the control rods absorb these neutrons, there is no way for the chain reaction to
continue and the reaction stops. Now because nothing is literally on fire like
in a coal plant, there is no carbon emission from this process.
So the operation of a nuclear power plant is completely green which is a good thing for
the earth. The huge plumes you see from the cooling towers
of nuclear powerplants is not pollution, but just water vapor from the condensation process
of turning the steam back into water. So heat is being released into the atmosphere, not
carbon dioxide or other greenhouse gases. Now it should be noted that nuclear power
isn’t completely renewable, because you do end up consuming fuel so to say.
The fuel, U-235, is turned into waste products like Krypton, Barium, and other elements of
the periodic table. This is in principle is fine because these elements exist naturally
anyway. The issue is however that these waste products
are generally radioactive isotopes of these elements, so we have to be careful with this
waste as it can be dangerous for humans due to radiation.
However, this is not the most problematic part of using this for nuclear fuel because
the half-life of these waste products is generally short, between a few days to 30 years for
the worst fission waste. So most of this waste turns into stable isotopes within a few years,
and becomes relatively safe. The bigger problem with using uranium for
fuel is that they also create a lot of other waste products from transmutation.
Transmutation is when an element absorbs a proton or a neutron, and turns into a different
element. So for example, when we mine Uranium ore from
earth, it is mostly composed of Uranium-238 which is fertile, meaning it cannot be split
to undergo fission. Less than 1%, about 0.7% of natural uranium
is fissile uranium-235 which can be split to power a nuclear plant.
This is one reason natural Uranium has to be enriched so that we end up with at least
a few percent of uranium-235 in it. This process is costly but necessary.
This also means that most of uranium fuel in a nuclear reactor is uranium-238, and not
U-235. This U-238 absorbs neutrons, but instead of
splitting it, undergoes transmutation into heavier elements like Plutonium and Americium.
The problem is that this Plutonium is very
toxic. And not only that, it can also be used for nuclear weapons.
Many people are against nuclear power plants specifically because of this latter fact,
that the plutonium generated from waste, can be used to make weapons of mass destruction.
The bottom line is, most of these heavier elements created by transmutation of U-238,
are not only nasty but also have a long half-life. This means we end up having to store these
waste products of hundreds, if not thousands of years before they becomes safe.
This is the big nuclear waste problem and a big reason why people don’t like nuclear
power. But Thorium is different. Thorium is element number 90, so is a slighty
lighter element than Uranium which is element 92. First, it’s much more abundant than
Uranium. In fact, we have more than 3 times more thorium
on earth than uranium. One reason we have more is because it’s more stable than uranium,
with a half-life of 14 billion years compared to the most stable uranium having a half life
of 4.5 billion years. So it simply lasts longer before decaying.
Not only that, but we can also more effectively use thorium as a fuel. It is estimated that
1 ton of thorium can produce the same amount of power has 200 tons of uranium.
The reason for this is because even enriched Uranium only contains about 3-5% U-235 which
is the fissile part. The remaining 95-97% is not only wasted but undergoes transmutation
to become more dangerous. But with Thorium, you end up using almost
all of it for fuel. Another aspect is that mining Thorium is also safer and more efficient.
This is because the brown ore, Monazite, that contains Thorium, has higher concentrations
of it than does the equivalent uranium ore. So the expensive process of enrichment is
not necessary with thorium. Now you might ask, what kind of a magic substance
is this and why aren’t we using it? Well there are some issues. To start with,
Thorium is fertile and not fissile. In other words, you can’t split it into two and make
energy. So what the heck! Why are we even talking about this?
Well, hold on a second, it can still be used. Thorium just has to be used in a different
way than traditional Uranium-fueled nuclear power plants.
To make it work, you need to use what’s called a breeding reactor. This is a kind of reactor
that creates its own fuel from non-fissile material.
How you ask? Well, you start with Thorium-232 from nature. Then you have a neutron source
such so you add one neutron to get Thorium-233. This isotope is not very stable and via the
weak force it will undergo a beta minus decay so that a neutron in its nucleus becomes a
proton, turning it into Protactinium-233. This isotope is also not stable and will again
undergo beta minus decay and transmute into Uranium-233.
So, great we started with Thorium and now we have created Uranium again? Isn’t this
what we were trying to avoid? Well, it turns out that just like Uranium-235
that we use in uranium fueled reactors, Uranium-233 is also fissile. So we can split it and make
a lot of energy. Now remember, that in uranium reactors the
waste problem is not really from splitting Uranium-235 because the fission waste products
have a relativity short half life. It’s the transmutation of the U-238 that
causes problems. Like U-235, Uranium-233 also creates waste
products that are relatively safe. But the difference is that with Thorium, almost all
of it is eventually used up in the fission process. There is very little U-238 like in
Uranium reactors that can end up transmuting to Americium and Plutonium, which are radioactive
and harmful to humans for long periods of time.
This is huge improvement over traditional Uranium nuclear power plants. Now the world
isn’t ideal, and neither is Thorium. Some of the Thorium in this process turns into
Uranium-232 instead of Uranium-233. Uranium-232 is not generally fissile. It’s
a contaminant and is very radio-toxic because it decays via processes that emits very high
energy gamma rays, which are harmful to humans. So it has to be handled with care.
One positive part is that spent fuel rods of Thorium containing uranium-232 contamination,
are not suitable for making nuclear weapons. So it makes these reactors peaceful and not
an instrument for making weapons grade nuclear material.
So if Thorium is so great why doesn’t everyone build these reactors? The answer is technical
and political. First, engineering and building a commercial
nuclear power plant of any kind, including a Thorium powerplant is hard and expensive.
Politically there are at least two issues. First, it’s hard to convince the public
that these plants can be safe and reliable, given how the world witnessed the disasters
at Fukushima in Japan, Chernobyl in Ukraine, and three-mile island in the United States
over the last few decades. Secondly, because Thorium doesn’t produce
military grade products that can be used in nuclear weapons, it did not see much government
funding, particularly during the cold war era.
But on the bright side, as with many things, who else but China is ahead of everybody else,
having completed a new Thorium test reactor last year, and is heavily investing in Thorium
as future power source. They may even have a plant ready to go by the end of this decade.
Ultimately, we the people can decide if we want this. There are plenty of reserves in
the world. India has the largest, and the US is second. These two alone have enough
to power the world for more than a thousand years.
I hope this shed some new light on an old subject, and perhaps made you reconsider nuclear
power as a solution to our increasing energy needs.
Guys I want to let you know that I have an announcement. If you want to meet me in person, I will be on stage at the
"Celebration of science and reason" conference in Vancouver, British Columbia on April 14 of 2022
this year, along with distinguished guests Sabine Hossenfelder and Lawrence Krauss.
Tickets are on sale now for this event at Pang-burn.com, the link is in the description.
So I hope to see you there. If you like this video, do us a favor and
subscribe. I’ll see you in the next video my friend.