Conference Session (B13)
Paper #150
Disclaimer—This paper partially fulfills a writing requirement for first year (freshman) engineering students at the University
of Pittsburgh Swanson School of Engineering. This paper is a student, not a professional, paper. This paper is based on publicly
available information and may not provide complete analyses of all relevant data. If this paper is used for any purpose other
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THORIUM REACTORS: THE SEARCH FOR A MORE SUSTAINABLE
FUTURE
Timothy Bryla, [email protected], Mena 3pm, Vincent Parlato, [email protected], Mena 1pm
Abstract—Thorium is currently being studied and is
displaying promise as an alternative fuel source to Uranium235, the current standard for nuclear energy. Nuclear power
has proven to be a valuable resource in regards to energy
production; however, the Uranium Plutonium reactors that
are being used currently have received criticism due to various
drawbacks. Studies regarding the implications of Uranium
show that the relative scarcity of the metal could be cause for
a greater emphasis on Thorium as another more readily
available energy source. In addition, the Uranium fuel cycle
produces radioactive isotopes that last several thousand years
longer than isotopes produced during the Thorium fuel cycle,
complicating the disposal of nuclear waste greatly. Continued
research and development by various design teams including
NASA has given rise to multiple reactor designs that utilize
Thorium with increasing levels of efficiency compared to older
models, as a safer outlook on the consequences of weapon
grade materials. Thorium as of now is widely available as a
raw resource due to current production means and has the
capability of creating significant amounts of safe, efficient
energy for years to come. Through extensive research and
comparisons of reputable peer reviewed sources, this paper
will serve to explain the significant benefits as well as
shortcomings of Thorium as a fuel source. The entire process
from mineral extraction to refinement and nuclear fission will
be analyzed for economic, ethical, and environmental issues
that could make Thorium a truly viable and sustainable fuel of
the future.
Key Words— Energy, Fuel, Fuel Cycle, Nuclear, Power
Generation, Thorium, Uranium
ALTERNATIVE SOURCES OF NUCLEAR
ENERGY
In today’s society, it is essentially impossible to live
without the assistance of some type of new science,
technology, or invention. These innovations serve one
purpose: to enhance life as we see fit. Whether that be by
increasing production, improving social interactions, or as a
form of entertainment, mankind is constantly improving and
inventing new ways to better the world. From commonplace
University of Pittsburgh Swanson School of Engineering 1
Submission Date 03.03. 2017
items, such cell phones, laptops, televisions, ovens,
refrigerators, or even toilets with running water, to larger, more
powerful machines such as automobiles, commercial
airplanes, and cruise ships, they all require some form of power
to run. Even items such as books or pens, which require no
power to utilize or operate, still require power to be produced.
It is common knowledge that energy is conserved, but where
does the energy that is used to power all these contraptions
come from? One might suggest that their house supplies power
through outlets, but houses obtain their power from powerplants. Most power-plants and machinery such as cars create
power from the burning of fossil fuels. However, if the supply
of fossil fuels is limited, what will mankind use to power all
those contraptions that depend on a source of power to
operate? Scientists have explored various forms of alternative
energy sources to traditional fossil fuels and natural gas but
they are still unsure as to what source will serve as a power
supply in the years to come.
The rise of nuclear energy began in the 1940’s during
World War II. Experimentations were conducted to develop
more powerful weapons, and focus was placed onto the
strength of nuclear reactions. Uranium was the main element
of focus, due to its ability to produce Plutonium, which is
needed for the production of atomic bombs [1]. After the war,
research laboratories and many tests were conducted to better
understand and develop Uranium and the nuclear cycle [2].
The possibility of utilizing Thorium as a fuel source in nuclear
reactors as compared to current Uranium fuel rods gives great
promise as a dedicated energy source.
Approaching the new millennium, there was a rise in
concern to the world energy crisis. Populations were rising
exponentially, and countries were struggling with supplying
the necessary energy. As people began to realize that fossil
fuels are finite, researchers began looking into other sources of
power such as wind, solar, and nuclear. Uranium was seen as
a source of generating power, and not just as a weapon.
Thorium, which is not particularly useful for manufacturing
bombs, was classified as another nuclear fuel source. Certain
methods of extracting Thorium from the ground are used, and
this is important for many nations that foresee a future with
Thorium reactors. However, nations face certain restriction on
their nuclear programs [3]. The question of using nuclear
energy has many ethical implications, due to the danger is
Timothy Bryla
Vincent Parlato
poses. Finally, the positive and negative effects that Thoriumbased energy has on the environment and world overall are
considered, and compared to the effects of current fuel sources.
Incorporating sustainability into a product or technology
is to say that the product helps protect the environment either
by reducing waste or improving energy and resource efficiency
so that the resources will be available long into the future.
Technologies that minimize our footprint on the environment
while maintaining a balance with economically viable and
affordable solutions serve to protect the earth for future
generations and support long term ecological balance. The
incorporation of Thorium into current energy production will
not only serve to extend the use of existing fuels by providing
an alternative, but it will also help to phase out certain fuels
that are having adverse effects on the environment.
There are various reasons why thorium may be more
beneficial than uranium, but before comparing the two
different nuclear fuels, it is essential that the fuel cycles be
discussed.
is non-fissile Uranium-238 [1]. Isotope separation is a
chemical technique of enriching one isotope relative to the
other. Ideally, the fissile Uranium-235 is enriched to between
3.5% and 5% [2]. As Uranium Hexafluoride is only a gas at
low temperatures it eventually cools and becomes solid again
inside the cylinders.
The Uranium is now nearly ready to be used as a fuel
source. It then goes through the final fabrication stage, where
the solid UF₆ is pressed into pellets. The pellets are then
compressed into long chains or rods of Uranium which is then
able to be used in the reactor core.
THE URANIUM FUEL CYCLE
Currently, nuclear energy is one of the more popular
sources of energy as compared to the traditional, carbon-based
fuel sources. While there are quite a few elements that can be
utilized by nuclear reactors to generate energy, the most widely
utilized one is Uranium. Uranium is fairly abundant, and
according to the World Nuclear Association is “about 500
times more abundant than gold,” with about the equivalent
parts per million in the Earth’s crust as tin. “It is present in
most rocks and soils,” and found in bodies of water such as
“rivers and in seawater” [2]. However, before it can be used
in a reactor, Uranium must first be excavated and milled,
converted, and enriched. The entire nuclear fuel cycle for
Uranium can be observed in figure 1. Uranium is mined from
the earth in its raw form, and must then be processed and
transformed into a form that is usable and ready to undergo the
fission process. From the ground, Uranium is removed from
the mined ore with various solvents. Once extracted, it is made
up of powdered Uranium Dioxide UO₂ , and Triuranium
Octoxide U₃ O₈ [2]. Because Triuranium Octoxide is one of
the more stable structures of Uranium, samples of UraniumDioxide may be reduced with Hydrogen to form U₃ O₈
concentrate [2]. The powder is then 70% to 90% Triuranium
octoxide and is known commonly as yellowcake due to the
yellow coloring caused by the Oxygen [1].
The next step in the preparation involves conversion and
enrichment of the Uranium. The Uranium undergoes multiple
chemical reactions to become Uranium Hexafluoride. The
UF₆ allows the Uranium to able to be heated up to a gas stage,
and then loaded into the reactor cylinders as the necessary
enrichment process will only work when the reactant is in a
gaseous state [1]. At this point, the yellowcake is not fissile
and therefore cannot produce energy through radioactive
decay. Only about .7% is the radioactive Uranium-235, the rest
FIGURE 1 [2]
Illustration displaying the process that Uranium goes
through before being ready for fission
Once in the reactor core, the Uranium-235 fissions and splits,
causing a chain reaction that converts the Uranium-238 into
Uranium-239. The chain reaction is an exothermic process and
produces a tremendous amount of heat which is converted into
electrical energy through the use of generators. About a third
of the Uranium becomes Plutonium [2]. While the Plutonium
can also be used in another fuel reactor to produce more
energy, it is also very easily utilized in the manufacturing of
atomic bombs. This poses a serious threat for nations around
the world due to the clear devastation nuclear warfare has the
potential to cause. Additionally, nuclear radiation has severe
and long-lasting environmental effects, and the radiation must
be factored into the discussion of the sustainability and
practicality of Uranium. Uranium is as widely popular as it is
today due to the fact that it is able to be used to produce
weapons of mass destruction. It was widely researched during
World War II for this reason, and only afterwards considered
for its application as an energy source. However, there are
other more abundant, cheaper, and less harmful elements that
may still undergo nuclear fission to produce power.
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Timothy Bryla
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of the Thorium fuel cycle will not only reduce the cost of
Thorium metal, it will also facilitate the production of more
efficient large-scale Thorium reactors capable of meeting the
energy needs for years to come thanks to its large abundance.
THORIUM EXTRACTION AND
PROCESSING
Thorium shares many similar properties with uranium,
and because of this, thorium can also be converted into energy.
As is with any means of energy production, the first step is
collecting natural resources that can then be converted into
useable and efficient forms capable of being processed into
energy. Much like coal or other solid natural resources,
Thorium must be mined from mineral rich ores generally
found in large veins concentrated in various areas. According
to researchers at the National Center for Policy Analysis,
Thorium has shown to be three times more abundant in Earth’s
crust than Uranium with concentrations in India, Turkey,
Brazil, Australia, and the United States [4]. The process of
extracting Thorium from mineral deposits has been explored
largely in part to the fact that it is a byproduct of mining for
other rare earth minerals such as ilmenite, rutile, magnetite,
and zircon, particularly in monazite ore [2][5]. This makes the
prospect of economic sustainability much more prevalent due
to the fact that less resources must be put into the extraction
process. Environmentally speaking, Thorium rich ore veins
exist with other valuable minerals and resources and as such
new veins will not have to be mined which could potentially
have adverse effects of the local ecosystem such as damaging
water flows. The fact that the infrastructure to mine Thorium
exists on a relatively large scale thanks to the necessity of these
other resources means that the major problem that exists now
is separating the Thorium and converting it into useable fuel.
Various processes of fuel conversion exist, but with further
research and development, the efficiency of Thorium fuel
conversion could significantly increase and make the prospect
of the future fuel source much more desirable to investors and
nations in need of substantial power production.
In order to extract Thorium from the monazite ore, the
ore must first be ground into a fine sand and treated with a
strong acid and alkali solution, often sodium hydroxide or
sulfuric acid to separate the metals. The Thorium and rare earth
metals are precipitated out in preparation for solvent
extraction. The metal mixture is combined with a suitable
hydrocarbon to separate the Thorium from the other metals and
is then removed from the organic compound with another acid
bath of nitric acid to produce the useable Thorium dioxide [6].
Thorium dioxide, now separated from the monazite ore,
can be fluorinated into Thorium tetrafluoride and heated to
around 650 degrees Celsius with calcium and a zinc halide to
produce a metal mixture capable of being separated into pure
Thorium [6]. It is this pure form of Thorium metal that is used
in the Thorium nuclear fuel cycle in reactors to create tangible
energy.
Although present with today’s production means, this
process is far from optimized due to the lack of emphasis on
Thorium as a valuable fuel source. The metal has little uses as
it is overlooked due to the existing Uranium based nuclear
reactors. Further research into the development and production
THE THORIUM FUEL CYCLE
The Thorium fuel cycle is well understood and
documented now after many years of research and observation.
Unlike the Uranium fuel cycle which involves Uranium-235 as
the fissile material, the Thorium fuel cycle involves the process
of enrichment and beta decay. Thorium-232 is bombarded with
neutrons from a fissile nuclear isotope, often Uranium-233, in
order to become Thorium-233. Thorium-233, which is a
radioactive isotope with a half-life of 22 minutes, decays
quickly into Protactinium-233 through the process of beta
decay by emitting an electron and an antineutrino.
Protactinium-233 then goes through the same process of beta
decay over the course of several months due to its half-life of
27 days.
Figure 2 [7]
Illustrates the Thorium fuel cycle
Once the Uranium-233 is made, a substantial amount of energy
is released that can be circulated through a medium and used
to turn a turbine to generate electricity [7]. In addition, the
Uranium-233 created can be used to continue the cycle by
providing neutrons, given there is a constant supply of
Thorium 232. The fact that a new source of neutrons does not
have to be continually added reduces the cost of acquiring raw
materials thus making this process much more viable in the
long term. Less stress is put on extracting these raw resources
from the ground and more effort can be put into sustaining the
fuel cycle.
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In comparison to the Uranium fuel cycle, the Thorium
fuel cycle has several economic and environmental
advantages. During the Uranium fuel cycle, a mixture of
Uranium-235 and Uranium-238 undergoes the process of
enrichment. The percentage of Uranium-235 in the mixture is
increased to between 3 and 5 percent, allowing nuclear fission
to take place. The Uranium-235 then bombards the Uranium238 with neutrons, converting it to Uranium-239 and in the
process releasing a tremendous amount of heat. However, in
addition to this heat are radioactive isotopes including
Plutonium, Americium, and Technetium with half-lives of
several thousand years [5]. The Thorium fuel cycle on the other
hand uses Uranium-233 to bombard Thorium with neutrons,
thus greatly reducing the amount of harmful radioactive
isotopes that are formed during the beta decay process of
Uranium which creates larger more unstable elements. The
isotopes that are created have half-lives of only several
hundred years and are created at a much lower rate than in the
Uranium fuel cycle [5]. The reduced need for long term storage
of these harmful radioactive isotopes not only benefits the
utilization of the element in terms of cost, but it also allows for
a greater sense of environmental sustainability in the sense that
these isotopes will decay long before existing nuclear waste
has the chance to decay. However, if thorium is to be utilized
as viable energy source, specific thorium reactors must be
constructed to harness the energy derived from the thorium
fuel cycle.
generate electricity, in this case with an eight-megawatt reactor
[9]. Engineers at the Oak Ridge Laboratory dedicate several
years of development and research to maintaining the reactor
with a great deal of success. With current technological
innovations, it is possible that this process could become vastly
superior to any existing Uranium-235 based reactors. Despite
the success, however, work on the process was halted and
Thorium as a fuel source was essentially forgotten.
The amount of research and testing done during this time
certainly had merit in regards to advancing nuclear power as a
whole. Nuclear power offered a new alternative energy source
that was previously untapped, and advancement brought about
by Thorium power development has the capability of being
utilized to advance current nuclear reactor designs. Efforts to
expand nuclear power generation have been made by many
nations with significant raw nuclear resources. Recently in
2013, The Chinese National Academy of Sciences has
dedicated 350 million dollars to the research and development
of Thorium reactors for large scale energy production across
the country, aiming to make a full-scale Thorium reactor
within 15 years. The Chinese Government hopes to combat the
arising energy crisis that is the result of a drastically rising
GDP [10]. In order to keep up with the increasing demand for
electricity, more efficient use of safe and readily available
natural resources must be considered. Because the groundwork
has already been laid out for Thorium Molten Salt Reactors,
Chinese scientists and engineers will be able to innovate past
research done at the Oak Ridge Laboratory to meet their own
needs of a sustainable, more energy-intensive future. However,
this process is still a massive undertaking that will require large
amounts of resources, both in terms of money as well as time
and raw materials. While having an expensive startup cost, the
promise of efficient energy conversion and production will in
time make up for the initial cost and serve to continue to
produce energy for many future generations to enjoy and
improve upon. The undertaking will be able to pay for itself
with enough time, and as such be economically sustainable if
certain regulations are met. As more time and funding is put
into the research of thorium, further emphasis, and
governmental oversight, will be placed on the development of
thorium power to ensure that it is properly developed.
THORIUM REACTORS IN PRACTICE
Virtually unexplored, Thorium reactors have long since
been overshadowed by traditional Uranium reactors. Nuclear
power was at the forefront of technological innovation during
World War II not for its use as a means of energy production,
but for the creation of fissionable radioactive material capable
of being used in atomic weaponry [4]. As a result, nuclear
reactors were designed only with the afterthought of
harnessing power. As such, various reactor designs have been
introduced that would greatly optimize and even replace the
current Light Water Reactors that are used today for energy
conversion of Uranium fuel.
A conversion method used in the 1960s by researchers at
the Oak Ridge Laboratory in Tennessee demonstrated that one
gram of the Radioactive Protactinium could be extracted from
200 grams of raw Thorium [8]. Molten Salt Reactors (MSR)
for example use molten fluorides at low pressures to dissolve
fuel and facilitate the Thorium nuclear fission fuel cycle [9].
The Oak Ridge Laboratory is one of the few examples that
prove the viability of Thorium as a nuclear fuel with the use of
a Molten Salt Reactor. The design utilized the liquid salt
Thorium Fluoride as a circulating and cooling agent that
absorbs radiation from the initial neutron bombardment of
Uranium-233. This breeder reactor design surrounds a reactor
core which it fertile fuel after the Thorium undergoes beta
decay to become fissile Uranium-233. This process generates
heat which is transferred by the molten salt to a gas turbine to
RESTRICTIONS AND REGULATIONS ON
NUCLEAR TECHNOLOGY
Nuclear energy has the potential to fix the energy crisis
faced by many nations in the world, vastly reduce greenhouse
gas emissions and environmental impact of humans, and help
aid in reducing the effects of global warming. However,
although the nuclear fission process generates an immense
amount of radioactivity and heat, if utilized properly it can be
used as a weapon of mass destruction. Atomic weapons are the
most powerful weapons known to mankind, and have the
capability to harm and kill millions of people, destroy the
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Timothy Bryla
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delicate environment, and threaten the Earth for future
generations with its long-term catastrophic effects.
technology. Research facilities may not possess more than 8
kg of Uranium for example, as that amount or higher is
considered a nuclear weapon grade material [2]. There is a
great push from many anti-nuclear organizations and countries
around the world to not only severely limit nuclear research,
but abolish it altogether. Due to the many national and
domestic restrictions, past nuclear explosions and the effects
directly correlated with them, and public objections to nuclear
technologies, research corporations and nations must not only
be extremely cautious with the experimentations they conduct
but also ensure that the research they carry out is for the sole
purpose of advancing and not harming the human race.
A Brief History of Nuclear Reactors
As stated earlier, Americans scientists started
experimenting with nuclear technology during world war two
and continued thus throughout the 1940’s [11]. Multiple
elements were experimented with, but however, due to the
inability of Thorium to create Plutonium, scientists started to
focus more on other elements such as Uranium. Plutonium is a
necessary element to form nuclear bombs, and Americans
were only concerned with developing a bomb powerful enough
to end the war. Thorium was not considered a viable option for
nuclear power until after the war in the 1960’s. The first
operational Thorium reactor was constructed at the Oak Ridge
National Laboratory in Tennessee [2]. Since then, several
countries have conducted research into Thorium reactors.
However, the 2011 meltdown at the Fukushima Daiichi
Nuclear Power Plant in Japan greatly alarmed many nations,
and thus caused them to remove any current, operational power
plants, or to scrub any future projects involving building new
reactors [11]. This was the first and only major nuclear disaster
since the 1986 Chernobyl nuclear accident that killed
thousands, but was much more controlled and lead to almost
no civilian deaths. After some time passed, and after
considerable evaluation regarding the safety and practicality of
nuclear energy, “China and India are gearing up” and
preparing to construct more nuclear power plants [11].
Thorium is being seriously considered as a future nuclear fuel
by many nations across the globe, and according to science
magazine, India is allegedly planning to have a Thorium-based
power plant by 2030 [11].
ETHICAL ISSUES
The previously mentioned aspects of the potential
hazards associated with nuclear power have led to intense
debates about the morality of nuclear energy. Some politicians
either listen to the logic of arguments against nuclear energy,
but in many cases, ignore the complaints all together. When
considering the practicality of a new technology, one must
consider whether said technology is overall beneficial to
humankind, or if the negative attributes outweigh the positive
attributes. Alternately, when considering the morality of a
specific science or technology, one must consider whether the
technology is right or if it has implications that may deem it
unethical. However, as right is a vague term, whether or not a
certain technology classifies as ethical varies depending on the
opinion of the person analyzing it.
Unfortunately, due to the destruction and multiple
accidents that have come from nuclear power, it has gained a
negative connotation of being extremely dangerous. Although
Thorium can undergo a series of neutron bombardment
reactions to become Plutonium and thus be viable for the
manufacture of atomic bombs, it is an incredibly costly,
lengthy process. This serves to deter nations from utilizing
Thorium as a material for bombs, especially when compared
to the relative ease of converting Uranium into Plutonium and
then atomic bombs [8]. In an ethical sense, this important piece
of information means that Thorium may serve as an effective
source of energy for developing countries. Thorium could be
provided to these countries for their nuclear research
programs, without the same risk of development of weaponry
that comes with Uranium. Thorium itself does have potential
hazards associated with it, but if properly utilized, thorium can
provide energy in a more sustainable sense than current fuel
sources.
Threat of Atomic Weaponry
Severe regulations and restrictions have been placed on
the research, manufacture, and usage of nuclear reactors. After
the effects of the bombs used on Nagasaki and Hiroshima, and
the threat of the outbreak of nuclear warfare during the Cold
War, certain measures have taken place to protect the safety of
many nations around the world. The Comprehensive Nuclear
Test Ban Treaty is a multinational treaty enacted in 1996, and
was ratified by only a few countries; that of which bans the
usage of all nuclear warfare and weaponry for war purposes
[3]. Another treaty, known as the Nuclear Non-Proliferation of
Nuclear Weapons or NPT, serves the similar purpose of
limiting the spread of nuclear weaponry, and is recognized or
ratified by most countries across the globe [3]. However, the
latter’s effectiveness in the prevention of nuclear technology is
greatly debated by many world officials. Many nuclear
weapons nations still have large stockpiles of produced and
capable nuclear weapons: in fact, there are an estimated 22,000
in various countries [3]. While certain restriction of nuclear
technology can be beneficial for the safety and wellbeing of all
nations, it can also impede the development of nuclear
SUSTAINABILITY AND ENVIRONMENTAL
IMPACT OF THORIUM
As the world population continues to grow, so too does
the demand for power. Oil rigs are starting to run dry,
greenhouse gases are raising global temperatures, and the
prices for fossil fuels are skyrocketing. As stated earlier,
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Thorium is a developing alternative energy source and is very
abundant, about four times more common than Uranium
[12]. Although the mining of any material will damage the
earth, Thorium deposits in particular are accompanied with
sulfide compounds. Sulfur has the property of being very
insoluble and acts as an acid-neutralizer. Because of this, the
extracted material will contribute very little to liquid pollution
in nearby bodies of water [13]. Thorium minerals only
contribute trace amounts of Thorium at about 1 part per billion
and are resistant to being broken down [13]. Uranium on the
other hand is quite soluble, which can lead to contamination in
lakes, rivers, and oceans [2]. America in particular has a
stockpile of about 3,000 tons of already milled Thorium from
the collection of other resources, thus greatly reducing the need
to collect more Thorium in the years to come [12]. It can be
seen that, on a broad scope, the collection of Thorium is much
more environmentally friendly compared to the damage that is
left to the surroundings by oil rigs and Uranium mines.
The benefits that the Thorium fuel cycle has over the
Uranium fuel cycle are not only economic, but also
environmentally friendly. Because the Thorium fuel cycle
creates the Uranium-233 needed to maintain the reaction, a
separate process to acquire the neutrons needed for beta decay
of the Thorium becomes unnecessary. As a result, the only
required resource that is regularly needed is additional
Thorium-232. With the amount of Thorium present in reserves
around the world, Thorium nuclear reactors, once created and
initially started with a steady supply of neutrons, would be able
to run strictly off of Thorium for a significant amount of time,
which would only have to be replaced after the inevitable
buildup of radioactive waste. The number of radioactive
isotopes created during the fuel cycle is also a factor of 1000
times lower than the number of radioactive isotopes created
during the Uranium fuel cycle, with half-lives that are only a
fraction as long [12]. This reduces the need for expensive long
term storage of large amounts of dangerous radioactive waste
and it also reduces the impact of accidental spills and
environmental contamination.
The collection of Thorium is attentively monitored and
regulated by the government to ensure the health and wellbeing of the environment and nearby life. Over the past
century, the Environment Protection Agency has proposed and
implemented a considerable amount of laws and standards for
Uranium and Thorium mills that preserve and support the
landscape [14]. Heavy environmental regulations may cost
research corporations more money, but ensure the continued
protection of the Earth.
Once out of the ground, Thorium is used as a potential
fuel source, and actually aids in the fight against global
warming. Thorium’s supply is finite, but it is estimated that
Thorium is so abundant that humans could not exhaust its
supply for multiple centuries to come [12]. Thorium also
produces an enormous amount of energy in comparison to the
miniscule, about a few kilograms, of material needed for the
reaction to take place. This is due to the science behind how
energy is derived from nuclear reactions. Unlike the energy
that comes from the burning of fuel in a chemical reaction,
nuclear reactions produce zero carbon emissions [12]. The
chemical reactions utilized in the reactor generate energy by
combusting a carbon-based fuel source, such as gasoline or
octane, in the presence of excess oxygen. The fuel is usually in
the form of long carbon chains, and when burned, the carboncarbon bonds break and release a tremendous amount of heat
and energy in the exothermic reaction. Since nuclear reactions
involve the breaking of extremely strong interatomic bonds
between protons and neutrons, the energy and heat release is
far greater than from the breaking of the weaker intermolecular
bonds [12]. Thus, because the nuclear reaction of Thorium
produces no greenhouse gases and generates immensely more
energy per mass of fuel, utilizing Thorium as an alternative
fuel source on a large enough scale would tremendously
reduce the current carbon emissions and would be an
enormous step forward in the direction of a greener future for
mankind.
EVALUATION OF THORIUM POWER
After careful examination, it can be argued that thorium
is a definitely a considerable option for the future supply of
power. Uranium, although the first element to be studied
heavily in regards to nuclear power, does not appear feasible
for the energy demands of the world. Uranium is much too
dangerous, both because of its ability to be utilized to for
powerful nuclear bombs, and its many environmental impacts
such as polluting seawater [2]. Mining Thorium is a relatively
simple process, that involves separating Thorium from other
minerals with reactions involving acids and bases [6]. While
the process can still be perfected, it is an efficient manner of
gathering usable Thorium samples.
The nuclear cycle involving Thorium is carefully
inspected and regulated, and rightfully so. Too many times in
history have the lives of innocents been drastically affected or
lost due to nuclear carelessness or accidents. As Thoriumbased power is developed and utilized at a higher rate than it is
now, there will need to be increased regulations and
restrictions put in place to ensure the protection of both the
environment and civilians.
Observation of the green impact Thorium has displays
why it is such a feasible option in regards to the environment.
Unlike Uranium, Thorium will not lead to pollution in nearby
bodies of water. The wonderful advantage that nuclear energy
has over fossil fuel combustion-based energy is the result that
nuclear-derived energy will not harm the atmosphere. Extreme
carbon emissions are a currently a massive global problem, and
the resulting greenhouse effect has accelerated global
warming. Cutting down on carbon emission is a challenge,
especially since the overwhelming majority of machines run
on carbon-based fuels, but switching power supplies over to
Thorium reactors would vastly improve the state of the
atmosphere and environment. Due to the relative abundance,
higher safety, and reduced environmental impact, Thorium
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Timothy Bryla
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fueled nuclear reactors could help answer the question for
finding an alternative energy source for a sustainable future.
http://mragheb.com/NPRE%20402%20ME%20405%20Nucl
ear%20Power%20Engineering/Thorium%20Resources%20in
%20%20Rare%20Earth%20Elements.pdf
[13] “Health and Environmental Protection Standards for
Uranium and Thorium Mill Tailings.” United States
Environmental Protection Agency. 1.24.17. Accessed 2.8.17.
https://www.epa.gov/radiation/health-and-environmentalprotection-standards-uranium-and-thorium-mill-tailings-40cfr
[14] “Health and Environmental Protection Standards for
Uranium and Thorium Mill Tailings.” United States
Environmental Protection Agency. 1.24.17. Accessed 2.8.17.
https://www.epa.gov/radiation/health-and-environmentalprotection-standards-uranium-and-thorium-mill-tailings-40cfr
SOURCES
[1] H. Chang, X. Jing, Y. Xu, Y. Yang. “Thorium-based Fuel
Cycles in the Modular High Temperature Reactor.” Tsinghua
Science and Technology. 01.18.2012. Accessed 1.26.17.
http://ieeexplore.ieee.org.pitt.idm.oclc.org/document/607596
0/
[2] B. Gosen. “Thorium Deposits of the United States-Energy
Resources for the Future?” United States Geological Survey.
2009.
Accessed
2.5.17.
https://pubs.usgs.gov/circ/1336/pdf/C1336.pdf
[3] “Nuclear Weapons.” United Nations Office for
Disarmament
Affairs.
2016.
Accessed
2.26.17.
https://www.un.org/disarmament/wmd/nuclear/
[4] S. Ashley, C. Boxall, R. Grimes, W. Nuttall, G. Parks.
“Nuclear Energy: Thorium Fuel has Risks.” Nature:
International Weekly Journal of Science. 11.06.2012.
Accessed
1.26.17.
http://www.nature.com/nature/journal/v492/n7427/full/49203
1a.html
[5] B. Taebi. “The ethics of nuclear power: Social experiments,
intergenerational justice, and emotions.” Science Direct. 2012.
Accessed 2.5.17.
http://www.sciencedirect.com/science/article/pii/S030142151
2007628
[6] W. Schulz. “Thorium Processing.” Encyclopedia
Britannica.
2.24.2011.
Accessed
2.26.17.
https://www.britannica.com/technology/thorium-processing
[7] A. Juhasz, R. Rangarajan, R. Rarick. “High Efficiency
Nuclear Power Plants Using Liquid Fluoride Thorium Reactor
Technology.” National Aeronautics and Space Administration.
10.2009.
Accessed
1.26.17.
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2009003
8711.pdf
[8] “Nuclear Fuel Processes.” Nuclear Energy Institute. 2015.
Accessed
1/26/17.
https://www.nei.org/KnowledgeCenter/Nuclear-Fuel-Processes
[9] “Current and Future Generation-Thorium.” (2015,
September). World Nuclear Association. (International
Association Corporate Website). Accessed 1.26.7.
http://www.world-nuclear.org/information-library/currentand-future-generation/thorium.aspx
[10] C. Hurst. “Fuel for Thought: The Importance of Thorium
to China.” Institute for the Analysis of Global Security. 2015.
Accessed 2/25/17 http://iags.org/thoriumchina.pdf
[11] M. Jacoby. “Trying to Unleash the Power of Thorium:
Proponents Aim to Tap Vast Nuclear Energy Potential of
Obscure Natural Resource” Chemical Engineering News.
07.6.2015.
Accessed
1.26.17.
http://cen.acs.org/articles/93/i27/TryingUnleash-PowerThorium.html
[12] M, Ragheb. “Thorium Resources in Rare Earth Metals.”
7.7.2016. Accessed 2.28.17.
ADDITIONAL SOURCES
A. Übeyli. “Burning of Reactor Grade Plutonium Mixed with
Thorium in a Hybrid Reactor.” Journal of Fusion Energy.
Accessed
1.26.17.
http://link.springer.com/article/10.1007/s10894-007-9078-1
B. Taebi. “The ethics of nuclear power: Social experiments,
intergenerational justice, and emotions.” Science Direct. 2012.
Accessed
2.5.17.
http://www.sciencedirect.com/science/article/pii/S030142151
2007628
C. Forsberg. “Definition of Weapons-Usable Uranium-233.”
Oak Ridge National Laboratory. 3.2.1998. Accessed 2/18/17
http://web.ornl.gov/info/reports/1998/3445606060721.pdf
J. Barnett & X. Zou. “The Potential of Thorium for Safer,
Cleaner and Cheaper Energy.” National Center for Policy
Analysis.
09.26.2014.
Accessed
1.26.17.
http://www.ncpa.org/pub/ib149
P. Bagla. “Thorium Seen as Nuclear's New Frontier.” Science
Mag.
11.13.2015.
Accessed
1.26.17.
http://science.sciencemag.org/content/350/6262/726
“Thorium-Based Seed & Blanket Technology.” World
Nuclear
Association.
3.2.17.
Accessed
3.3.17.
http://www.ltbridge.com/fueltechnology/thoriumbasedseedan
dblanketfuel
ACKNOWLEDGMENTS
We would like to thank Julie Hartz for being such a great
asset to our paper as well as being incredibly understanding of
our position as freshmen engineering students. We would also
like to thank our writing instructor Liberty Ferda for bearing
with us as we completely changed our topic to something that
we felt more comfortable writing. Special thanks go out to
patrons of the library who are always respectful and allow for
an atmosphere conducive to being productive learners. And
lastly we extend a very gracious thank you to our good friend
Isaac for suggesting the idea of Thorium reactors.
7
Timothy Bryla
Vincent Parlato
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