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While nuclear power raises fear among many of us, it's considered one of our better options
for a reliable, carbon-free future. Alongside small modular reactors, molten salt reactors
(MSRs) that use Thorium as a fuel, are considered cheaper, cleaner and safer options to the
traditional reactors fueled with the highly radioactive elements and can benefit a nuclear
energy expansion. With experimental tests scheduled for a Thorium-reactor in China and
US companies developing projects that should be spinning up in the next few years, let's
revisit Thorium energy and molten-salt reactors, and when we'll be able to see their impact.
Could Thorium reactors build a cheaper and safer future for nuclear power?
I'm Matt Ferrell. Welcome to Undecided
In 2020, I produced a video on Thorium reactors explaining what they are, why people were
excited about them, and if they could really be the future of green energy. But at that
time, at least here in the U.S., we hadn't seen significant progress in projects involving
molten salt reactors. For example, in 2019 the construction of the experimental power
plant for the traveling-wave reactor (TWR) developed by TerraPower was suspended. That
was a significant loss for the company, considering that the cost to demonstrate a reactor like
that was about a billion dollars according to the CEO of TerraPower, Chris Levesque.
Also, due to the technical and practical challenges of molten salt reactors, Lin-Wen Hu, director
of research and irradiation services at MIT’s Nuclear Reactor Laboratory had said:
”There is still a lot of work to be done in terms of demonstrating molten-salt reactor
technology, even for uranium-based reactors. Molten-salt reactors need to be demonstrated
with a uranium fuel cycle before that system can be used for a thorium fuel cycle. Moving
toward a thorium fuel cycle has a lot of unknowns.”
But since then there's actually been some progress.
Before we take a deep dive into recent news on thorium and molten salt reactors, let's
quickly review what they are, how they work, and what pros and cons they have. That means
getting into the chemical concepts behind the operation of these rectors.
You're probably aware that nuclear reactors are responsible for containing and controlling
nuclear fission, which is a process where atoms split and release energy in a chain
reaction. In short, atoms are bombarded with neutron particles, fissioning the atoms into
two smaller atoms and some additional neutrons. Some of those neutrons go on to hit other
atoms ... and this cycle keeps going.
Inside the nuclear reactor is a robust steel vessel containing the reactor core where the
fission occurs. It uses a fuel that's usually a radioactive metal like Uranium-235 (U-235)
or Plutonium-239 (Pu-239). Along with the core is a moderator, that's usually water
or graphite, which is used to reduce the speed of the neutrons coming from the fission process
in order to feed the chain reaction. The heat generated by the reaction in the core is used
to create steam to turn a turbine and generate electricity.
In order to ensure safety in the nuclear reaction, reactors have control systems called "rods"
that speed up or slow down or even stop the nuclear reaction if necessary. The control
rods are typically made out of neutron-absorbing materials like silver and boron, but the element
that's used depends on mechanical and lifetime characteristics, the neutron energy inside
the reactor, and how it resists neutron-swelling.
If something goes wrong while controlling the nuclear reaction, this can cause the reactor's
core to meltdown due to excessive heat produced from the chain reaction. And this can be catastrophic,
like what happened with Three Mile Island, Chernobyl, or Fukushima. And all of these
accidents haven't helped public perception, which has held back interest in pushing nuclear
power policy ahead.
This is where Thorium-fueled reactors have an edge over other nuclear energy technologies.
But before I get to that, I’d like to thank Surfshark for sponsoring today’s video.
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below. Thanks to Surfshark and to all of you for supporting the channel. Now back to why
Thorium-fueled reactors have an edge over other nuclear energy technologies.
Thorium-fueled reactors offer a potentially safer, cleaner, and more abundant alternative
to traditional reactors fueled with the highly radioactive elements.
Thorium is a naturally occurring, slightly radioactive metal that was isolated in 1828
by the Swedish chemist Jons Jakob Berzelius. It was 60 years later that the reactive nature
of Thorium was discovered by Gerhard Schmidt and Marie Curie. Thorium is found in small
amounts in most soils and rocks, where it's about three times more plentiful than Uranium.
The most common source of Thorium is monazite, a rare-earth phosphate mineral that contains
up to 12% Thorium phosphate.
Th-232 is the most stable of the 27 Thorium isotopes, which decays very slowly. This isotope
isn't itself fissile and so it can't be used directly in a thermal neutron reactor. However,
when absorbing a neutron, Th-232 will transmute to Th-233, which beta decays to Protactinium-233
(Pa-233).
There's a whole chemistry class in here, which goes beyond the scope of this video ... and
my brain, but anyway ...
After Th-233 beta decays once, it undergoes a second beta decay to become Uranium-233
(U-233), which is an excellent fissile fuel material. This fuel cycle is very important
to molten salt reactors because most of the proposed reactors rely on this cyclical process.
One big benefit of Thorium reactors is the much smaller half-life of the nuclear waste.
U-233 can be separated from the Thorium, which sets it apart from U-235 and U-238. It's U-235
that contains very radioactive isotopes with half-lives of thousands of years. A standard
nuclear reactor's waste needs to be stored safely for up to 10,000 years until the isotopes
decay. On the flip side, the waste from a Thorium reactor is radioactive for about 500
years.
Another benefit of Thorium breeding Uranium-233 is that it can be used in other types of nuclear
reactors like Heavy Water Reactors (PHWRs), High-Temperature Gas-Cool Reactors (HTRs),
Boiling Water Reactors (BWRs), Pressure Water Reactors (PWRs), and more. Even so, the main
reactor type that's being explored for Thorium is Molten Salt Reactors (MSRs).
There are many different types of MSRs, including the Molten Salt Breeder Reactor, which is
commercially known as a Liquid Fluoride Thorium Reactor (LFTR). While conventional nuclear
reactors use solid fuel, LFTRs use a liquid fuel in the form of very hot fluoride salt
that also serves as the coolant, and also operates at low pressure. In these reactors,
rather than solid fuel rods, Thorium is dissolved into the liquid fluoride salt before sending
it into the reactor chamber at temperatures above 1,112ºF, equivalent to 600ºC.
A great benefit of these reactors is that they can self-regulate the process to maintain
the temperature within an appropriate range. As the temperature in the reactor goes up,
the rate at which the fission reactions occur goes down. In addition, the liquid fuel is
run through a reaction chamber filled with graphite rods that reduce the speed of neutrons,
and if these rods are removed, the chain reaction stops. It's a more reliable emergency braking
system than traditional nuclear reactors.
Another benefit is the increased fuel efficiency in LFTRs. Because there is no cladding, there
is little neutron loss, meaning all neutrons are used in the reaction, not for crashing
into the cladding. This increases overall efficiency and the life of the fuel.
In order to make MSR even safer, there's a freeze plug safety mechanism built into the
reactor plumbing. So if this plug is taken out, the reactor salt goes down the drain
... so to speak. Imagine that a natural disaster happens, and the nuclear power plant undergoes
a blackout, the reactor would safely power down without the need for any human intervention.
The interest in Thorium isn't just for its potential safety. Although we don't have a
commercial reactor operating currently, it's expected that Thorium-fueled reactors will
have a lower price than traditional fission reactors. From the economics perspective,
Thorium-fueled reactors make sense for several key reasons.
First, these systems operate at low pressure and high heat capacity, which means the containment
vessels can be smaller and thinner. Also, Thorium-fueled reactors require fewer components
for fuel assemblies; they're basically composed of just vats of fuel, making them simpler
and cheaper to build. To make it better, due to their operation at high temperatures, the
heat losses are lower, so the efficiency goes up. Finally, while conventional reactors need
to be shut down for refueling, LFTR can be refueled while operating at full power.
While there are some major advantages to Thorium-fueled reactors, they aren't perfect and there are
several challenges that have been holding back their mainstream adoption.
The main concern with MSRs is that radioactive fission products could potentially leak from
the containment vessels. They are just in a big, sealed vat. Traditional reactors keep
their fuel in solid pieces surrounded by cladding. On top of that, these nuclear plants will
require periodic maintenance, but all of the equipment will contain high levels of radioactivity,
which can make maintaining the components harder and riskier. Also, there's a proliferation
risk because Thorium makes Uranium-232, which emits gamma rays. This irradiation process
can be altered slightly by removing Pa-233, forming U-233, which could be used in nuclear
weapons. Another concern is that while Thorium is more plentiful than Uranium, it is more
expensive to mine.
Despite these challenges, the several pros of Thorium reactors have resulted in some
projects being developed around the globe. Let's take a look at what's changed since
my last video on Thorium energy.
Some countries like France, India, Japan, Norway, and the U.S. have reported some development
on Thorium nuclear reactors, but there are no plans for their commercialization yet.
On the other hand, China is closing in on Thorium energy. It launched its molten-salt
reactor program in 2011, investing $500 million. The Chinese government has been developing
an experimental reactor based on an MSR technology developed by researchers at Oak Ridge National
Laboratory (ORNL) in the 1950s. Originally designed for aircraft propulsion in the Manhattan
Project, the ORNL's 7.4 MWth (Megawatt thermal) output experimental reactor ran for over four
years. The project was closed due to a corrosion problem and cracked pipes caused by the hot
salt, as well as the weak radioactivity of Thorium. These issues made fission reactions
unsustainable without adding Uranium. China has put modern technology to use with better
materials, instrumentation and controls in order to build its reactor.
The experimental prototype generates 2 MWth, enough to supply 1,000 homes, and should have
started in September 2021 in the Gobi Desert near the city of Wuwei. However, researchers
working on the reactor haven't confirmed whether the tests have already started. If the prototype
works as designed, China has plans to build a commercial 373MW version by 2030.
In the U.S., the California-based Kairos Power plans to have a 50 MW demonstration reactor
operational in Oak Ridge, Tenn. by 2026. The company received $303 million from the U.S.
Department of Energy for the design, licensing, and construction of the Hermes low-power demonstration
reactor. Kairos Power's application for building the reactor will go through a review process
with federal regulators. The reviews regarding safety and environmental impact should be
completed by September 2023.
Also, in November 2021, Southern Company and the Department of Energy (DOE) came to an
agreement on designing, building and operating the Molten Chloride Reactor Experiment, which
will push forward the Molten Chloride Fast Reactor that has been developed by TerraPower.
By the way, TerraPower has announced that it will build its Molten-Salt Reactor in Kemmerer,
Wyoming, where the coal-fired Naughton Power Plant has been closed. This 345MW reactor
has been developed jointly with GE Hitachi Nuclear Energy, combining liquid sodium cooling
and a molten-salt heat-storage system that will better integrate renewable energy.
According to the Thorium Reactor Market research report, the global Thorium market is expected
to grow at a CAGR of 11.1% between 2021 and 2027. In addition, the global molten salt
reactors market is projected to reach $18.7 billion by 2031 according to Visiongain Research
Inc.
When it comes to the levelized cost of electricity (LCOE), a study published in the International
Journal of Sustainable Energy showed an LCOE of a Thorium molten salt reactor at $53.51/MWh
with a 30-year lifespan. Comparatively, the study showed an LCOE for a pressurized water
reactor (PWR) at $63.08/MWh for a 30-year lifespan, so according to the study, Thorium-based
reactors could be a cheaper option among nuclear technologies.
There's one added bonus that nuclear energy can bring us, and this was mentioned a lot
in the comments on my nanotechnology and water desalination video I put out a little while
ago, and that's ... water desalination. The heat generated by nuclear power plants combined
with electricity can be used for water desalination, which means removing salt and minerals from
seawater and turning it into potable water. Because molten salt reactors don't use water
to cool down the core, they don't need a large water supply
to run. .
So it sounds like Thorium might be a win. But do we really need nuclear power to build
a renewable energy future?
When compared to solar and wind, nuclear energy is still more expensive. The Levelized Costs
of New Generation Resources in the Annual Energy Outlook 2021 from the EIA showed that
for new resources entering service in 2026, onshore wind had an LCOE of $31.45/MWh, while
solar was at $29.04/MWh without energy storage. With a four-hour battery system the price
goes up to $42.18/MWh. It's also important to consider that the cost for storing energy
in batteries has been steadily decreasing, falling from $187/MWh in 2019 to $150/MWh
in 2020 for a four-hour discharge time, which benefits intermittent power sources like solar
and wind.
Even though nuclear power can provide stable electricity generation for the grid, these
power plants are usually expensive, complex, legally challenging and take longer to build
compared to solar, wind, and hydropower. With an average construction time of 6 years and
the issues regarding nuclear waste storage, there are some hurdles to overcome. New investments
and progress in Thorium and molten salt reactors make a compelling case for their potential
benefits. However, there's still a long road ahead in order to verify how they'll perform
in real life.
So what do you think? Do you think Thorium reactors will make an impact? And do you think
we need nuclear as part of the energy mix at all? Jump into the comments and let me
know. And thanks as always to my patrons and welcome to new Supporter+ members Randy Meibaum,
Phil Stiller, and Producer Josie Marie. All of your direct support really helps with producing
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