America and the world face enormous challenges relating to the
procurement of energy, and to the corresponding security ramifications
this represents. There exists today a virtually-unknown alternative to
the standard uranium fuel cycle for nuclear power reactors, which offers
a variety of significant strategic and economic advantages. This
alternative is thorium.
Thorium is not new
technology, but rather, it is as old as the nuclear age itself, with
research ongoing since its inception. The first nuclear reactors in
America and Russia were fuelled by thorium. It was then dismissed by
policy-makers – the key reason being that the thorium fuel cycle
provides no opportunity for obtaining bomb materials. The 21st Century
is a different era than the Cold War era. The Obama Administration has
recently announced its goal to rid the entire world of nuclear weapons
while it must confront both energy and environmental crises. Fossil
fuels are expensive and experience wildly volatile price fluctuations.
Uranium is in dangerously short supply. The world was not ready for
thorium in the 1950s. Thorium could not be more appropriate now.
The Basics
Thorium
is a naturally-occurring fertile material – the only other one on earth
besides natural uranium. Like uranium, 232-thorium can accept a slow
neutron and transmute into a nuclear fuel, which then undergoes nuclear
reactions, releasing enormous amounts of energy. The fissile material
created is 233-uranium isotope. This thorium fuel cycle carries with it
a number of important natural properties some of which contrast sharply
with the uranium fuel cycle:
-At no point in the thorium cycle – from mining to waste – can fuel or waste products be used as bomb material in any way;
-The
thorium fuel cycle is inherently incapable of causing a meltdown
according to the laws of physics; in nuclear reactor parlance, the fuel
is said to contain passive safety features;
-Thorium-based fuels do
not require conversion or enrichment – two essential phases of the
uranium fuel cycle that are exceedingly expensive, and create
proliferation risk;
-Thorium fuel cycle waste material consists
mostly of 233-uranium, which can be recycled as fuel (with minor
actinide content decreased 90-100%, and with plutonium content
eliminated entirely);
-Thorium-based fuels are significantly energy efficient;
-Thorium
fuel cycle waste material is radiotoxic for tens of years, as opposed
to the thousands of years with today’s standard radioactive waste;
-Thorium fuel designs exist today that can be used in all existing nuclear reactors;
-Thorium
exists in greater abundance and higher concentrations than uranium
making it much less expensive and environmentally-unobtrusive to mine;
These
facts have many serious implications for the efficiency and security of
energy delivery in the United States, and the world.
Proliferation resistance
Proliferation
resistance is important in a nuclear fuel solution for many reasons.
Thorium delivers added security to every nuclear installation using
thorium fuels, as well as to every other phase of the fuel cycle,
including mining, processing, fuel fabrication, waste, and all the
transport in between each phase. Each of these phases and the
corresponding transport require heavy security in order to protect
against theft or sabotage of radioactive materials. By using thorium,
processing is not even required and all security can be dramatically
reduced because the threat simply does not exist.
Abroad,
the benefit to having proliferation-resistant nuclear energy in foreign
locales is obvious. Never again will the world worry that a foreign
state developing its own nuclear program is not genuine about its
motives. With a thorium fuel cycle in place, the foreign state in
question reduces their costs significantly, increases their energy
efficiency, increases their access to fuel, and eliminates any
international doubt of their probity.
Passive safety
Serious
doubt was cast on nuclear energy as a viable power source by the
significant accidents at Three Mile Island in the US state of
Pennsylvania and in Chernobyl, Ukraine. Generation III reactors are now
built with passive safety features where the laws of nature — such as
gravity or the laws of thermodynamics — take over to stop any possible
runaway reactions, leakage or any other kinds of accidents. The laws of
nature cause the reactors to shut down, and remove disaster control
measures from requiring human intervention. Thorium fuel continues
this tradition, and marginally improves on this natural safety feature.
Thorium fuel does not burn as hotly as uranium fuel. This also
explains why it burns longer, and more thoroughly. The meltdown
scenario is not at all possible with thorium fuel.
The
benefits of the total passive safety of reactors to international
security are obvious. An extension of this feature of thorium is that
it makes nuclear reactor stations impervious to terrorist attacks.
Furthermore, by obviating this possibility, security costs at these
power stations can be dramatically reduced. A cheaper energy supply
provides security the world over.
Elimination of enrichment phases
The
standard fuel cycle practiced in the nuclear sector today requires that
natural uranium, once mined, undergo an expensive, complex chemical
process to increase its content of the 235-uranium isotope. This is the
isotope that is fissile, and occurs naturally in mined uranium to the
extent of 0.711% of the total mass. This fissile material must be
concentrated to between 3% and 5% of the total uranium mass in order to
be sufficient to create nuclear reactions within the reactor. This is
the same material that, if concentrated to 85%+ of the total mass of
uranium, in sufficient quantities – approximately 10 kilograms or more –
can be used to make nuclear weapons.
Enrichment
is a two-step process. Firstly, the natural uranium is mined, and then
transported under security, to a conversion facility, where the uranium,
in the naturally-occurring form triuranium octaoxide (U3O8), known as
yellowcake, is converted into gaseous uranium hexafluoride (UF6). This
gas is then transported under security to the enrichment facility, where
the UF6 is enriched to 3%-5% 235UF6. This enriched material is then
transported under heavy security to the fuel fabrication facility, where
it is solidified once again, and then crafted into pellets, rods and
finally highly complex bundles. From there, the fuel bundles are
transported under heavy security to the reactor. For countries that
have nuclear power stations, but do not have their own enrichment
facilities (most don’t), these shipments must cross international
boundaries. The waste product of this process is depleted uranium,
which is stored at the enrichment site.
At
present, the Republic of Iran has raised international concern by
engineering their own enrichment technology, without the approval of the
United Nations. Iran claims that they wish to enrich uranium in order
to utilize it as fuel for nuclear power stations in their country.
However, with the enrichment technology in hand, they also have the
ready capability, if they choose, to develop bomb-grade material.
Thorium
does not require any conversion or enrichment. Thorium naturally
occurs in the form thorium dioxide (ThO2), with no isotopic content.
Thorium oxide, which is not fissile and cannot be weaponized in any way,
can be transported directly to the fuel fabrication facility for
manufacture into pellets, rods and bundles, and then transported to the
reactor. In this scenario, there are only two transports required –
compared to four for uranium – and only one transport that requires
heavy security.
With thorium, an enormous
infrastructure of expensive and risky transport, as well as the
associated security, is entirely eliminated. Once again, besides the
cost benefits, the benefits to national and global security are clear.
Improved waste profile
The
waste profile of today’s standard nuclear fuel cycle is problematic.
It contains lethal radioactive material, including approximately 1%
fissile plutonium, as well as significant quantities of so-called minor
actinides: curium, americium, and neptunium. Any of these materials can
be concentrated to produce nuclear weapons materials. At present, the
United States has no stated policy for the processing of nuclear waste.
The material is stored at 100 nuclear reactor sites, where they are
subject to theft or attack. Internationally, some countries have their
waste material reprocessed, but there is only one facility in the world
at present that can reprocess the material – located in France.
The
waste profile of the thorium fuel cycle is a vast improvement. The
vast majority of the waste is the 233-uranium isotope. 233U can be
reprocessed to be used as fuel in a closed thorium fuel cycle, however
the technology for this is not yet available. In the meantime, 233U
cannot be used to make bomb material because of its natural properties.
Specifically, it is because 233U contains 232uranium isotopic content,
whose decay products give off significant gamma rays, that would fry the
electronics in any conceivable bomb mechanism not to mention being
fatal for any human being within several meters, making transport of
weapons impossible. Moreover, these gamma rays would be immediately
detectable by the most basic satellite surveillance. Bomb fabrication
from 233U, though technically possible, is so impractical that it is
considered impossible. Minor actinide waste in the thorium fuel cycle
is reduced by as much as 99.99% in some models.
Increased energy efficiency
Due
to the chemical properties of thorium, when it is used as fuel in a
nuclear reactor, it has the ability to give off more neutrons than it
absorbs. This means that the neutron economy of any contemplated
thorium fuel cycle is superior to the uranium fuel cycle. The fuel
burns longer and uses all of the fissile material required to ignite a
reaction.
As explained above in today’s standard
fuel natural uranium is enriched to increase its concentration of 235U
fissile content. Approximately two-thirds of this fissile material is
burned, with the remainder in the waste product. Natural uranium in the
fuel absorbs a neutron to eventually become 239-plutonium.
Approximately 0.9% of the final waste consists of this 239-plutonium
isotopic material. When concentrated, this is the best material for
bomb production. It is due to an inherently inefficient fuel cycle that
there is so much residual material.
In the
thorium fuel cycle, 232-thorium absorbs a neutron to breed 233-thorium,
which decays naturally in 22 minutes into 233-protracinium, which decays
naturally after 27 days to become 233-uranium. One hundred per cent of
this 233-uranium burns in the reaction (as opposed to only two-thirds
of the 238U-bred fuel.) However, approximately one out of every ten
233-Pa molecules are lost in the decay process and become a 234-uranium
isotope. In sum, thorium-bred fuel burns with 90% efficiency, whereas
uranium-bred fuel burns with only 66% efficiency. The waste products
are, respectively, 233U, which cannot be used for bomb production, and
239Pu, which is the best possible bomb material.
The
energy differential from this efficiency has been demonstrated to be
anywhere from 60% to 200% greater. It should also be noted that because
thorium fuel does not require enrichment, whereas uranium fuel does,
much less raw material is required. In order to produce one year’s
worth of fuel for an average reactor (the US average reactor capacity is
1,000 Megawatts of electricity (MW), approximately 550,000 pounds of
natural uranium is required. Seven-eighths of this material has the
235-uranium extracted out of it, leaving unusable depleted uranium waste
behind. Because thorium does not require enrichment, only one-eighth,
or 69,000 pounds of raw material is required for the same energy
output. However, there is not even an equivalent energy output because
of thorium’s enhanced neutron economy and enhanced fissionability
characteristics. Therefore, this 69,000 pounds, a full one-eighth of
the material required for standard fuel will generate 60% to 200% more
energy output.
Thorium creates enormous
efficiencies from the micro- to the macroscopic level of fuel, and at
virtually every stage in the cycle. Enhanced efficiency translates
directly into decreased costs. At the risk of sounding repetitive,
cheaper energy provides security benefits the world over.
Short-lived radiotoxicity of waste
Spent
nuclear fuel in the current paradigm must be stored in a water medium
for cooling, before being stored in a special containment chamber.
Currently, these containment chambers exist at nuclear reactor sites.
For nearly 20 years, the US government has labored to develop a national
storage facility for this waste at Yucca Mountain in Nevada, against
broad opposition. Billions of dollars in research has been spent, with
billions more being allocated to a sinking fund for the construction of
such a facility by utility companies who own and operate reactors. Very
recently, the Obama Administration decreed that work on Yucca Mountain
was to cease immediately. The sinking fund remains.
Thorium-based
waste, also highly radioactive, has the distinction of being radiotoxic
for a far shorter time period. The half-lives of 233U’s decay products
are far shorter than the half-lives of the transuranic wastes mentioned
above. These dangerous periods can be measured in tens of years rather
than thousands. Certainly, to decrease the period during which these
waste products are lethal also provides security benefits.
Thorium fuel utilizable in existing reactor designs
There
are no significant infrastructural impediments whatsoever to using
thorium fuels in all existing reactor designs in the immediate present.
This is also a s security benefit. Typically, any new energy
technology, particularly a nuclear energy technology, must pass through a
series of daunting obstacles related to legislation, technology
development, regulation, user education and finally market penetration
before being implemented. For thorium, the reactors themselves require
virtually no modifications, and no regulatory paradigm changes in order
to accommodate thorium fuel. So this technology development continuum
only applies to the fuel development itself, which is a much easier,
faster, safer and cheaper exercise.
Security of supply
Perhaps
the most significant benefit to security is the abundant supply of
easily available thorium. Approximately 190 million pounds of uranium
is required in 2009 to fuel the 437 reactors in operation globally.
However, less than 110 million pounds of uranium will be produced from
mining in 2009. The balance must be provided by blended-down weapons
material, and from inventories. At the end of 2012, the Russian
contract to provide the United States and others with material from
their weapons expires, and the Russians have announced that they will
not renew the contract. They require the material for their own civil
energy program. The uranium shortfall in 2009 that must be filled from
inventory is approximately 26 million pounds. By 2016, this shortfall
is estimated to be 106 million pounds, and will continue to increase.
By 2020, approximately 150 million pounds of uranium will be required
from an inventory stockpile every year in order to keep reactors from
operating below capacity. These figures take into account new reactors,
and new uranium mines. By 2020, the international stockpile will be
dangerously depleted, and the material that reactors depend on will
either become unavailable, or will skyrocket in price. This partially
explains why the price of uranium increased from $7 per pound in 2001 to
$135 per pound in 2006. With the retrenchment of oil prices and the
global economy in general, the price of uranium has also retrenched to
the $40-45 price range. Nevertheless, the problem remains, and it is
far more critical than the attention paid to it.
The
United States is probably the most vulnerable to this developing
uranium supply crisis. At present, the US is forced to import over 90%
of its uranium required for reactor fuel. There are new uranium mines
being planned, but there are also 19 new reactor builds permitted as of
this writing. Each average reactor requires, on average, 550,000 pounds
of uranium feedstock. In 2008, the US produced 3.9 million pounds.
The supply required for the new facilities alone will be at least 10.5
million pounds, not to mention the 57.2 million or so pounds required
for the existing US reactor fleet. There is no question that the United
States is facing a serious problem.
Uranium must
be mined from underground, typically requiring costly infrastructure.
The mining methods are: the In-Situ Leach (or ISL), or the even
costlier, more environmentally-obtrusive open pit mining. Because of
the technical complexity and because of the extreme environmental impact
involved, an extraordinary level of regulation is required to ensure
the safety of uranium mining practices. This further increases costs,
and slows down new production. A very typical life cycle for a uranium
mine will be 10-15 years from discovery to the first year of
production. And then the mine’s lifespan may only be 5-10 years (as is
common).
Uranium typically occurs at very low
grade in nature – 1% of weight or less. This makes mining operations
themselves expensive, even after the large capital expenditure for
infrastructure. Mine operating costs, including the processing, can
amount to $25-50 per pound. Once again, this is over and above the
typical $50-100 million capital cost sunk into mine construction and
development.
Thorium mining is an entirely
different proposition. Large supplies of thorium exist in surface
mineral sands in nearly every corner of the world. These sands can be
mined by dredge mining, which is well-known as being an environmentally
unobtrusive mining technique. Without having to go underground, the
infrastructure and operating costs are a small fraction of any uranium
mining operation. These mineral sands are also highly concentrated with
thorium, and can contain tens or hundreds of millions of pounds of
thorium per deposit. In short, thorium is readily, cheaply and easily
available in large quantities. The US itself has enough
easily-extractable thorium to power its reactors for thousands of years.
Thorium
can also act as a useful supplement to uranium if necessary. With a
secure supply of thorium, a nuclear fuel supply crisis can be averted,
meaning that energy supply need not be interrupted.
At present, thorium is not purposely mined anywhere in the world.
The Future of Thorium
Leading
thorium fuel cycle research is taking place in India, Norway, Russia,
Canada and elsewhere. This research is very advanced in nature. The US
faces a security issue by becoming an also-ran in this technology
race. The US Congress has latently realized this. That is why on March
24, 2009, only eight days after the Bill’s introduction, the Congress
directed the US Navy to investigate the use of thorium-based nuclear
reactors for naval use. Elsewhere in the United States legislative
environment is the “Thorium Energy Independence and Security Act” – a
bill drafted by Nevada and Utah state senators, Harry Reid and Orrin
Hatch. The objective of this bill is to appropriate funds for thorium
research and education both in the US and abroad.
The
benefits of the US exporting safe, clean, proliferation-resistant
nuclear technology and fuel to other nations are clear. World nations
can safely take advantage of emission-free energy without any threat of
nefarious use.
With all the serious concerns of
nuclear energy addressed, the world can have more confidence that
nuclear is a safe technology, and that nuclear accidents or attacks will
not have any possible apocalyptic side effects. With an increased
adoption of nuclear energy, the entire world’s dependence on fossil
fuels can decrease dramatically. At present, there are 437 nuclear
reactors in the world, providing approximately 18% of the entire world’s
power. Nuclear energy is the only long-run, sustainable and viable
alternative energy available to the world today. If the adoption of
nuclear could be increased to 50% from less than 20%, carbon emissions
would experience enormous declines, thereby alleviating the problem of
climate change. And this represents yet another matter of security.
With a true nuclear renaissance, brought about with the help of the thorium fuel cycle, the world will become more secure.
A.Canon Bryan is President and CEO of New Energy Metals Corporation
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