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Lessons for the LiquidFluoride Thorium Reactor from history


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Title: Lessons for the LiquidFluoride Thorium Reactor from history

Lessons for the Liquid-Fluoride Thorium
Reactor(from history)
  • Kirk Sorensen
  • July 20, 2009
  • Mountain View, California

Executive Summary
Energy Generation Comparison
230 train cars (25,000 MT) of bituminous coal
or, 600 train cars (66,000 MT) of brown
coal, (Source World Coal Institute)

or, 440 million cubic feet of natural gas (15 of
a 125,000 cubic meter LNG tanker),
6 kg of thorium metal in a liquid-fluoride
reactor has the energy equivalent (66,000 MWhr
electrical) of
or, 300 kg of enriched (3) uranium in a
pressurized water reactor.
Each ounce of thorium can therefore produce
14,000-24,000 of electricity (at
2007 World Energy Consumption
The Future Energy from Thorium
5.3 billion tonnes of coal (128 quads)
31.1 billion barrels of oil (180 quads)
2.92 trillion m3 of natural gas (105 quads)
6600 tonnes of thorium (500 quads)
65,000 tonnes of uranium ore (24 quads)
Todays Uranium Fuel Cycle vs. Thoriummission
make 1000 MW of electricity for one year
35 t of enriched uranium (1.15 t U-235)
Uranium-235 content is burned out of the fuel
some plutonium is formed and burned
  • 35 t of spent fuel stored on-site until disposal
    at Yucca Mountain. It contains
  • 33.4 t uranium-238
  • 0.3 t uranium-235
  • 0.3 t plutonium
  • 1.0 t fission products.

250 t of natural uranium containing 1.75 t U-235
215 t of depleted uranium containing 0.6 t
U-235disposal plans uncertain.
Within 10 years, 83 of fission products are
stable and can be partitioned and sold.
One tonne of natural thorium
One tonne of fission products no uranium,
plutonium, or other actinides.
Thorium introduced into blanket of fluoride
reactor completely converted to uranium-233 and
The remaining 17 fission products go to geologic
isolation for 300 years.
How it all began
The Discovery of Thorium
  • Thorium was discovered in 1828 by the Swedish
    scientist Jons Jacob Berzelius.
  • Berzelius named thorium after Thor, the Norse god
    of thunder.
  • There was little to say about thorium when it was
    first discovered apart from its specific weight
    and its high-temperature capabilities.
  • thallium, thorium, thulium

Thorium is Radioactive
  • In 1898, Marie Curie made a remarkable discovery
  • Thorium and uranium were radioactive!
  • But with a 15 billion-year half-life (older than
    the universe), it didnt decay very often and had
    very low radioactivity
  • Eventually thorium decays to lead-208.

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Natural Decay Chains
  • There are four natural decay chains, three of
    which still exist on Earth. The fourth is
    extinct due to rapid decay.

Uranium (4n2)
Lead 206
Polonium 218
Radon 222
Thorium 230
Uranium 238
Radium 226
Pb,Bi,Po 210
Pb,Bi,Po 214
Th,Pa,U 234
21 yr
26 min
3 min
3.8 day
1600 yr
80000 yr
247 kyr
4.5 Gyr
Actinium (4n3)
Tl,Pb 207
Pb,Bi 211
Polonium 215
Radon 219
Fr,Ra 223
Ac,Th 227
Th,Pa 231
Uranium 235
36 min
0.0018 sec
4 sec
11 days
21 yr
32500 yr
700 Myr
Thorium (4n)
Tl,Pb 208
Pb,Bi,Po 212
Polonium 216
Radon 220
Radium 224
Ra,Ac,Th 228
Thorium 232
10 hr
0.15 sec
55 sec
3.64 day
6.7 yr
14.1 Gyr
Neptunium (4n1)
Astatine 217
Thorium 229
Neptunium 237
Francium 221
Bi,Po 213
Ra,Ac 225
Pa,U 233
Tl,Pb,Bi 209
2.14 Myr
162 kyr
7340 yr
10 days
0.032 sec
47 min
5 min
Three Conceptual Breakthroughs
Nuclear Fission (1939)Otto Hahn and Lise Meitner
discover that neutrons cause uranium atoms to
split, releasing energy.
The true nature of the nucleus (1935)Hideki
Yukawa hypothesizes that the nucleus consists
protons and neutrons bound together by a nuclear
force that overcomes the inherent repulsion of
the protons to one another.
Radioactivity (1896)Henri Becquerel discovered
that some elements (uranium and thorium) emit
particles spontaneously.
Lesson for LFTROnce youve figured out how
matter really works, you realize that if youre
looking for a dense source of energy, nuclear
fission is your answer.
Three basic options for fission
The fission of U-235 was discovered by Otto Hahn
and Lise Meitner in 1938.
Uranium-235 (0.7 of all U)
Pu-239 as a fissile fuel was discovered by Glenn
Seaborg in March 1941.
Uranium-238 (99.3 of all U)
U-233 as a fissile fuel was discovered by
Seaborgs student John Gofman in February 1942.
Thorium-232 (100 of all Th)
Could weapons be made from the fissile material?
Uranium-235 (highly enriched uranium)
Natural uranium
Isotope separation plant (Y-12)
Hiroshima, 8/6/1945
Depleted uranium
Isotope Production Reactor (Hanford)
Pu separation from exposed U (PUREX)
Trinity, 7/16/1945 Nagasaki, 8/9/1945
PROBLEM U-233 is contaminated with U-232, whose
decay chain emits HARD gamma rays that make
fabrication, utilization and deployment of
weapons VERY difficult and impractical relative
to other options. Thorium was not pursued.
Isotope Production Reactor
uranium separation from exposed thorium
U-232 decays into Tl-208, a HARD gamma emitter
Thallium-208 emits hard 2.6 MeV gamma-rays as
part of its nuclear decay. These gamma rays
destroy the electonics and explosives that
control detonation. They require thick lead
shielding and have a distinctive and easily
detectable signature.
14 billion years to make this jump
Some 232U starts decaying immediately
1.91 yr
1.91 yr
1.91 yr
3.64 d
3.64 d
3.64 d
Uranium-232 follows the same decay chain as
thorium-232, but it follows it millions of times
faster! This is because 232Th has a 14
billion-year half-life, but 232U has only an 74
year half-life! Once it starts down the hill it
gets to thallium-208 (the gamma emitter) in just
a few weeks!
55 sec
55 sec
0.16 sec
U-232 Formation in the Thorium Fuel Cycle
Lesson for LFTRThoriums no good for nuclear
weapons.Of course, if its wartime, this fact
isnt going to help you get developed.
The chain-reaction
Nuclear Criticality A Condition of Balance
10,000 fissions lead to 9999 fissions the
reactor is subcritical and the fission rate will
10,000 fissions lead to 10,000 fissions the
reactor is critical and the fission rate will
stay the same.
10,000 fissions lead to 10,001 fissions the
reactor is supercritical and the fission rate
will increase.
Self-controlling Fission Reactors are Possible
Analogy mass-spring system
Implementation fission reactor
  • It was clear that achieving perfect criticality
    (multiplication factor of 1.00000000000000000)
    was impossible by any active control
  • But natural effects could be used to tune in
    the reactor to perfect criticality
  • Expansion of water (reduced moderation)
  • Expansion of fuel (reduced fuel)
  • Increased neutron absorption in fuel (Doppler
  • This is the principle of the temperature
    coefficient of reactivity, which needs to be
    prompt, negative and strong

The rate of fission governs the amount of heat
added to the waterbut the density of the
returning water governs the fission rate (through
Gravity pulls downward on the mass...but the
springs force is proportional to its extension.
1942 The First Nuclear Reactor CP1
Lesson for LFTRYou want a reactor with a
negative, prompt, and strong temperature
coefficient of reactivity.
1944 A tale of two isotopes
  • Enrico Fermi argued for a program of fast-breeder
    reactors using uranium-238 as the fertile
    material and plutonium-239 as the fissile
  • His argument was based on the breeding ratio of
    Pu-239 at fast neutron energies.
  • Argonne National Lab followed Fermis path and
    built the EBR-1 and EBR-2.
  • Eugene Wigner argued for a thermal-breeder
    program using thorium as the fertile material and
    U-233 as the fissile material.
  • Although large breeding gains were not possible,
    THERMAL breeding was possible, with enhanced
  • Wigners protégé, Alvin Weinberg, followed
    Wigners path at the Oak Ridge National Lab.

Fission/Absorption Cross Sections
Lesson for LFTROnly thorium can be fully
consumed in a thermal spectrum reactor.To fully
consume uranium you MUST have a fast spectrum
Thorium-233 decays quickly to protactinium-233
Protactinium-233 decays slowly over a month to
uranium-233, an ideal fuel
Uranium-233 fissions, releasing energy and
neutrons to continue the process
Natural thorium absorbs a neutron from fission
and becomes Th-233
1944 A tale of two isotopes
But Eugene, how will you reprocess the fuel fast
enough to prevent neutron losses to
Well build a fluid-fueled reactor, thats how
Th-232 in
FertileTh-232 blanket
Chemical separator
Chemical separator
FissileU-233 core
New U-233 fuel
Fission products out
Lesson for LFTRIn fluid form, many of the
drawbacks of thorium can be overcome.In fluid
form, the xenon-135 can be removed continuously.
1951 Experimental Breeder Reactor 1
In 1951, Fermis protégé Walter Zinn and his
Argonne team successfully operated the first
liquid-metal-cooled fast spectrum breeder reactor
at a site in Idaho. The reactor produced enough
power to light a few light-bulbs, but was
heralded as the first power-producing reactor in
the world.
1952 Homogeneous Reactor Experiment - 1
In 1952, Weinbergs ORNL team duplicated this
accomplishment by building the first aqueous
homogenous reactor (HRE-1), which produced about
100 kWe of electrical power.
The HRE was not a thorium breeder (yet) but was
intended to prove the technology for one.
1958 Homogeneous Reactor Experiment - 2
HRE-2 was built to a thermal power of 5 megawatts
and further developed AHR technology.
ORNL Fluid-Fueled Thorium Reactor Progress
1947 Eugene Wigner proposes a fluid-fueled
thorium reactor
1950 Alvin Weinberg becomes ORNL director
1952 Homogeneous Reactor Experiment (HRE-1)
built and operated successfully (100 kWe, 550K)
1959 AEC convenes Fluid Fuels Task Force to
choose between aqueous homogeneous reactor,
liquid fluoride, and liquid-metal-fueled reactor.
Fluoride reactor is chosen and AHR is
cancelled. Weinberg attempts to keep both aqueous
and fluoride reactor efforts going in parallel
but ultimately decides to pursue fluoride reactor.
1958 Homogeneous Reactor Experiment-2 proposed
with 5 MW of power
Aircraft Nuclear Program
  • Between 1946 and 1961, the USAF sought to develop
    a long-range bomber based on nuclear power.
  • The Aircraft Nuclear Program had unique
    requirements, some very similar to a space
  • High temperature operation (gt1500 F)
  • Critical for turbojet efficiency
  • 3X higher than sub reactors
  • Lightweight design
  • Compact core for minimal shielding
  • Low-pressure operation
  • Ease of operability
  • Inherent safety and control
  • Easily removeable

Aircraft Nuclear Program allowed ORNL to develop
It wasnt that I had suddenly become converted to
a belief in nuclear airplanes. It was rather
that this was the only avenue open to ORNL for
continuing in reactor development. That the
purpose was unattainable, if not foolish, was not
so important A high-temperature reactor could be
useful for other purposes even if it never
propelled an airplane Alvin Weinberg
Radiation Damage Limits Energy Release
  • Does a typical nuclear reactor extract that much
    energy from its nuclear fuel?
  • No, the burnup of the fuel is limited by damage
    to the fuel itself.
  • Typically, the reactor will only be able to
    extract a portion of the energy from the fuel
    before radiation damage to the fuel itself
    becomes too extreme.
  • Radiation damage is caused by
  • Noble gas (krypton, xenon) buildup
  • Disturbance to the fuel lattice caused by fission
    fragments and neutron flux
  • As the fuel swells and distorts, it can cause the
    cladding around the fuel to rupture and release
    fission products into the coolant.

Ionically-bonded fluids are impervious to
  • The basic problem in nuclear fuel is that it is
    covalently bonded and in a solid form.
  • If the fuel were a fluid salt, its ionic bonds
    would be impervious to radiation damage and the
    fluid form would allow easy extraction of fission
    product gases, thus permitting unlimited burnup.

The Birth of the Liquid-Fluoride Reactor
  • The liquid-fluoride nuclear reactor was invented
    by Ed Bettis and Ray Briant of ORNL in 1950 to
    meet the unique needs of the Aircraft Nuclear
  • Fluorides of the alkali metals were used as the
    solvent into which fluorides of uranium and
    thorium were dissolved. In liquid form, the salt
    had some extraordinary properties!
  • Very high negative reactivity coefficient
  • Hot salt expands and becomes less critical
  • Reactor power would follow the load (the aircraft
    engine) without the use of control rods!
  • Salts were stable at high temperature
  • Electronegative fluorine and electropositive
    alkali metals formed salts that were
    exceptionally stable
  • Low vapor pressure at high temperature
  • Salts were resistant to radiolytic decomposition
  • Did not corrode or oxidize reactor structures
  • Salts were easy to pump, cool, and process
  • Chemical reprocessing was much easier in fluid
  • Poison buildup reduced breeding enhanced
  • A pot, a pipe, and a pump

The Aircraft Reactor Experiment (ARE)
  • In order to test the liquid-fluoride reactor
    concept, a solid-core, sodium-cooled reactor was
    hastily converted into a proof-of-concept
    liquid-fluoride reactor.
  • The Aircraft Reactor Experiment ran for 100 hours
    at the highest temperatures ever achieved by a
    nuclear reactor (1150 K).
  • Operated from 11/03/54 to 11/12/54
  • Liquid-fluoride salt circulated through beryllium
    reflector in Inconel tubes
  • 235UF4 dissolved in NaF-ZrF4
  • Produced 2.5 MW of thermal power
  • Gaseous fission products were removed naturally
    through pumping action
  • Very stable operation due to high negative
    reactivity coefficient
  • Demonstrated load-following operation without
    control rods

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The Fireball
  • The Fireball, or Aircraft Reactor Test, was the
    culmination of the ANP effort at ORNL.
  • 235UF4 dissolved in NaF-ZrF4
  • Designed to produce 60 MW of thermal power
  • Core power density was 1.3 MW/L
  • NaK used to transport heat to jet engines at 1150
  • 1500 hours (63 days) design life
  • 500 hours (21 days) at max power
  • The Fireball pressure shell was only 1.4 meters
    in diameter!
  • Contained core, reflector, and primary heat
    exchanger inside
  • The Fireball was considered the superior design
    for the ANP, but the program was cancelled in
    1961 before it was built.

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Lesson for LFTRSometimes the right answer
comes from an unexpected direction.Fluoride
fuel is the only practical way to build a
high-temperature, high-power-density reactor.
Weinberg wanted a civilian fluoride reactor
Until then I had never quite appreciated the
full significance of the breeder. But now I
became obsessed with the idea that humankinds
whole future depended on the breeder. Alvin
MSBR58 Reactor Plant Isometric
Image source ORNL-2634 MSRP Status Report, pg 3
Fluorination made separating UF4 and ThF4 easy
  • Fluorination was a basic chemical advantage of
    the fluoride-fueled approach
  • UF4 (in solution) F2 ? UF6 (gaseous)
  • Bred uranium-233 could be easily removed from a
    thorium fluoride mixture using this approach.

Lesson for LFTRNature is sometimes kind.The
ability to separate uranium from thorium under
high radiation and at high temperatures argues
strongly for a fluoride fueled reactor.
A chance meeting leads to the MSRE
By the end of 1959, our engineering development
program had proceeded far enough that we felt
justified in proposing an MSR experiment (MSRE),
but getting money and permission appeared
difficult. Then one day I heard a rumor that
Frank Pittman, who had succeeded Ken Davis as
director of the DRD, had expressed interest in
funding as many as four quick and dirty reactor
experiments provided that each one should cost
less than a million dollars. As I remember it, I
wrote a proposal that night and submitted it
through channels the next day. I outlined the
general features of the reactor, and by analogy
with another reactor system for which a cost
estimate had been made. I came up with a cost
estimate of 4.18 million. The proposal was
accepted, although by the time the design had
been detailed the cost estimate had
doubled. H.G. Mac MacPherson from The
Molten-Salt Adventure
Conceptual Framework of the Molten-Salt Reactor
The conceptual design of the MSRE was arrived at
as follows. To keep the reactor simple we
intended to simulate only the fuel stream of a
two-fluid breeder reactor, so that no thorium
fluoride was included. We wanted the neutron
spectrum to be near thermal, as it would be in a
commercial reactor, and since graphite was the
moderator, this dictated the minimum physical
size. The moderator was in the form of a
1.37-m-diam x 1.62-m-high right circular
cylinder. Had it been smaller, the neutron
leakage would have caused the neutron spectrum to
be more energetic than we wished. We would have
liked to have a higher power density, but cost
considerations limited us to 10 MW of heat.
There was also another reason for limiting the
power of the reactor. The AEC accounting rules at
the time allowed us to build a 10-MW reactor as
an experiment, using operating funds. A higher
power reactor would have required us to obtain a
capital appropriation and would have limited our
freedom to make changes. Actually we
miscalculated the heat transfer characteristics
and the reactor operated at only 8 MW. H.G.
Mac MacPherson from The Molten-Salt
Molten Salt Reactor Experiment (1965-1969)
View inside the MSRE test cell
MSRE Reactor Vessel
Water-cooled Fuel Salt Pump Motor
Heat Exchanger
MSRE Demonstrated Refueling, Fluorination and
Online Refueling
Vacuum Distillation
An amazing safety featurethe freeze plug
  • The reactor is equipped with a freeze plugan
    open line where a frozen plug of salt is blocking
    the flow.
  • The plug is kept frozen by an external cooling

Freeze Plug
  • In the event of TOTAL loss of power, the freeze
    plug melts and the core salt drains into a
    passively cooled configuration where nuclear
    fission is impossible.

Drain Tank
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MSRE Building (ORNL 7503) today
Lesson for LFTRBe ready for an opportunity to
demonstrate your idea.A working example is
worth stacks of documents and theory.
Two-Fluid 1000-MWe MSBR July 1964
Two-Fluid 250-MWe MSBR February 1967
ORNL-4119, sec 5
Two-Fluid 250-MWe MSBR August 1967
ORNL-4191, sec 5 ORNL-4528, sec 5
Two-Fluid 250-MWe MSBR August 1967
ORNL-4191, sec 5 ORNL-4528, sec 5
Two-Fluid 250-MWe MSBRPlan View of Steam
Generator and Drain Tank Cells
ORNL-4528, pg 22
Two-Fluid 250-MWe MSBRSectional Elevation of
Reactor Cell
ORNL-4528, pg 21
A Simple Fuel Cycle
Uranium Absorption and Reduction
Fluoride Volatility
Fluoride Volatility
Vacuum Distillation
Fuel Salt
Fertile Salt
Fission Product Waste
Recycle Fertile Salt
Recycle Fuel Salt
Two-Fluid Reactor
Two-Fluid Reprocessing with Details
Image source ORNL-3791, pg 119
Graphite Lifetime Limits Fluence
  • The primary consideration for reactor lifetime is
    the graphite distortion, which is a strong
    function of fluence and temperature.

Lesson for LFTRThe plumbing problem is a
real problem for the two-fluid reactor.Graphite
s problems need to be understood and
managed.But the overall appeal of the two-fluid
reactor is great.
One-Fluid 1000-MWe MSBR
Image source ORNL-4832 MSRP-SaPR-08/72, pg 6
One-Fluid Concept had very complicated
Lesson for LFTRFixing one problem can create
another, often bigger than the first.Perhaps
the two-fluid reactor should be revisited!
A Pressurized-Water Reactor
Typical Pressurized-Water Reactor Containment
  • This structure is steel-lined reinforced
    concrete, designed to withstand the overpressure
    expected if all the primary coolant were released
    in an accident.
  • Sprays and cooling systems (such as the ice
    condenser) are available for washing released
    radioactivity out of the containment atmosphere
    and for cooling the internal atmosphere, thereby
    keeping the pressure below the containment design
  • The basic purpose of the containment system,
    including its spray and cooling functions, is to
    minimize the amount of released radioactivity
    that escapes to the external environment.

Close-Fitting Containments
Lesson for LFTRIf you want a close-fitting
containment, dont have anything in there that
changes phases when the pressure changes (like
water) or undergoes violent reactions (like
liquid sodium).
  • I found myself increasingly at odds with the
    reactor division of the AEC. The director at the
    time was Milton Shaw. Milt was cut very much
    from the Rickover cloth he had a singleness of
    purpose and was prepared to bend rules and
    regulations in achievement of his goal. At the
    time he became director, the AEC had made the
    liquid-metal fast breeder (LMFBR) the primary
    goal of its reactor program. Milt tackled the
    LMFBR project with Rickoverian dedication woe
    unto any who stood in his way. This caused
    problems for me since I was still espousing the
    molten-salt breeder.

  • Milt was like a bull. He enjoyed
    congressional confidence so his position in the
    AEC was unassailable. And it was clear that he
    had little confidence in me or ORNL. After all,
    we were pushing molten-salt not the LMFBR. More
    that that, we were being troublesome over the
    question of reactor safety.

  • Congressman Chet Holifield was clearly
    exasperated with me, and he finally blurted out,
    Alvin, if you are concerned about the safety of
    reactors, then I think it may be time for you to
    leave nuclear energy. I was speechless. But it
    was apparent to me that my style, my attitude,
    and my perception of the future were no longer in
    tune with the powers within the AEC.

  • As I look back on these events, I realize that
    leaving ORNL was the best thing that could have
    happened to me. My views about nuclear energy
    were at variance with those of the AEC and
    Congressional leadership. After all, it was I
    who had called nuclear energy a Faustian bargain,
    who continued to promote the molten-salt breeder

Lesson for LFTREven if you invented the
light-water reactor, your bosses will still fire
you if you interfere with their plans.
Radiotoxicity of fission products decays in a few
hundred years.
fission products
101 102 103
104 105 106
Radiotoxicity of fission products decays in a few
hundred years, relative to natural U ore.
U ore mined to fuel the reactor
fission products
101 102 103
104 105 106
Radiotoxicity of unburned plutonium etc from
uranium reactor decays more slowly.
101 102 103
104 105 106
Radiotoxicity of unburned plutonium etc from an
LFTR is 10,000 x less.
plutonium etc
101 102 103
104 105 106
Incomplete Combustion
90 fission
65 fission
80 fission
75 fission
Lesson for LFTRAvoid making transuranics while
you make power.You can do this with thorium.
Spent Fuel Accumulates from each LWR
Projected Spent Fuel Accumulation without
Lesson for LFTRUnder current regulations,
Yucca Mountain cant hold all the spent nuclear
fuel.Especially if you build more LWRs.
GNEP Technology Demonstration Facilities
Aqueous Reprocessing works but is complicated
Fluoride reprocessing is very simple in comparison
Thorium tetrafluoride
Fertile Salt
Recycle Fuel Salt
External batch processing of core salt, done on
a schedule
Uranium Absorption- Reduction
Fuel Salt
Recycled 7LiF-BeF2
Hexafluoride Distillation
Recycle Fertile Salt
Bare Salt
Vacuum Distillation
Fluoride Volatility
HF Electrolyzer
Fission Product Waste
MoF6, TcF6, SeF6, RuF5, TeF6, IF7, Other F6
Could we use fluoride reprocessing for existing
spent fuel? YES!
  • Fluorinate the oxide fuel
  • Separate the uranium
  • Burn the TRUs
  • Isolate the fission products
  • Build LFTRs to stop making more waste

Long-term Radiotoxicity of Fission Products is low
Lesson for LFTRUse fluoride reprocessing
technology to help fix current concerns with
spent nuclear fuel.Use it to start new LFTRs
that dont contribute to the problem.
Waste generation from 1000 MWyr uranium-fueled
light-water reactor
Conversion to natural UF6 (247 MT U)
Mining 800,000 MT of ore containing 0.2 uranium
(260 MT U)
Milling and processing to yellowcakenatural U3O8
(248 MT U)
Generates 170 MT of solid waste and 1600 m3 of
liquid waste
Generates 600,000 MT of waste rock
Generates 130,000 MT of mill tailings
Enrichment of 52 MT of (3.2) UF6 (35 MT U)
Fabrication of 39 MT of enriched (3.2) UO2 (35
Irradiation and disposal of 39 MT of spent fuel
consisting of unburned uranium, transuranics, and
fission products.
Generates 314 MT of depleted uranium hexafluoride
(DU) consumes 300 GWhr of electricity
Generates 17 m3 of solid waste and 310 m3 of
liquid waste
Uranium fuel cycle calculations done using WISE
nuclear fuel material calculator
Waste generation from 1000 MWyr thorium-fueled
liquid-fluoride reactor
Mining 200 MT of ore containing 0.5 thorium (1
MT Th)
Milling and processing to thorium nitrate ThNO3
(1 MT Th)
Generates 0.1 MT of mill tailings and 50 kg of
aqueous wastes
Generates 199 MT of waste rock
Disposal of 0.8 MT of spent fuel consisting only
of fission product fluorides
Conversion to metal and introduction into reactor
Breeding to U233 and complete fission
Thorium mining calculation based on date from
ORNL/TM-6474 Environmental Assessment of
Alternate FBR Fuels Thorium
Todays Uranium Fuel Cycle vs. Thoriummission
make 1000 MW of electricity for one year
35 t of enriched uranium (1.15 t U-235)
Uranium-235 content is burned out of the fuel
some plutonium is formed and burned
  • 35 t of spent fuel stored on-site until disposal
    at Yucca Mountain. It contains
  • 33.4 t uranium-238
  • 0.3 t uranium-235
  • 0.3 t plutonium
  • 1.0 t fission products.

250 t of natural uranium containing 1.75 t U-235
215 t of depleted uranium containing 0.6 t
U-235disposal plans uncertain.
Within 10 years, 83 of fission products are
stable and can be partitioned and sold.
One tonne of natural thorium
One tonne of fission products no uranium,
plutonium, or other actinides.
Thorium introduced into blanket of fluoride
reactor completely converted to uranium-233 and
The remaining 17 fission products go to geologic
isolation for 300 years.
2007 World Energy Consumption
The Future Energy from Thorium
5.3 billion tonnes of coal (128 quads)
31.1 billion barrels of oil (180 quads)
2.92 trillion m3 of natural gas (105 quads)
6600 tonnes of thorium (500 quads)
65,000 tonnes of uranium ore (24 quads)
  • Thorium and the liquid-fluoride reactor give us
    many options for inherently safe,
    proliferation-resistant, economic nuclear power
    that can last for thousands, if not millions of
  • Fluoride reactor technology offers real options
    for solving the long-term issues surrounding
    spent nuclear fuel and ultimately preventing the
    formation of new transuranic waste.
  • Thanks Google!
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