coal2thorium.com 
Converting Power Plants
From
coal2nuclear
Chapter 1
THE THORIUM-FUELED
NUCLEAR BOILER
Directory
The purpose of this page is to introduce you
to our best "Technology Opportunity."
Thorium-fueled liquid
reactors
The
best "Technology Opportunity" for both Global Warming and rising
electricity costs.
A Thorium-Fueled Liquid Reactor as
described by Dr. Edward Teller, inventor of the hydrogen bomb.
This web site will focus on the "Heavy" electricity
industry 1,000 megaWatt (e) thorium-fueled liquid reactor designed by EBASCO
(1972) but never built.
Cruder than a Civil-War locomotive boiler, a liquid reactor heated
boiler should cost less to build than its equivalent coal heated boiler.
A QUICK INTRODUCTION TO MOLTEN SALT REACTORS
MAGIC TEAM: THORIUM-FUELED MOLTEN SALT REACTORS
About using molten
salt as a coolant.
QUICK HISTORY OF
THORIUM-FUELED MOLTEN SALT REACTORS
Nuclear Aircraft Engines 1946-1962
After
Nuclear Aircraft Engines
Dr. Ralph Moir and Dr.
Edward Teller (inventor of the Hydrogen Bomb) advocate MSRs
THE GOOD:
Molten Salt Reactor advantages
THE BAD: Molten Salt Reactor shortcomings
THE UGLY: When running,
thorium's U-232 radiation keeps terrorist's hands out of the cookie
jar.
THE ROUGH SPOTS:
General Considerations
Uncertainties, unanswered questions
References
Molten Salt
Reactor Basics
More about Molten
Salt Reactors
Advanced LIQUID FLUORIDE
THORIUM (LFTR) Nuclear Reactors
A molten salt reactor and your hot water heater are similar devices.
MSR - Safety and Licensing Aspects of the Molten Salt Reactor - 120507.pdf
________________________________________________________________________________________
Introduction:
We are talking about a
combination of TWO entities:
1. Thorium instead of Uranium as a
nuclear fuel.
2. Unpressurized (incapable of exploding) molten salt cooled liquid fuel reactors rather than
high pressure (capable of exploding) water cooled solid fuel rod reactors.
A QUICK INTRODUCTION TO MOLTEN SALT REACTORS
A QUICK INTRODUCTION TO MOLTEN SALT REACTORS
1.
Solid salt, if heated hot enough, will melt into a clear water-like liquid
(color-coded yellow in sketch at right). At the temperatures discussed here, the salt is far
below its boiling point and, since the salt has little vapor pressure, Molten
Salt reactors are unpressurized and thus incapable of making a steam-like
explosion.
2.
Uranium can be dissolved in molten salt.
A tub of molten salt with some radioactive uranium dissolved in it (think blood
- which carries nutrients) will become a
nuclear reactor if rods of synthetic non-flammable "nuclear" graphite (vertical black bars in reactor sketch) are
inserted into the liquid salt pool to promote nuclear fission (think muscle -
which turns nutrients into energy).
3.
If the pool becomes hotter than the design temperature, the liquid
salt expands, reducing the concentration of radioactivity near the nuclear graphite
rods, thereby reducing the intensity of the nuclear chain reaction. If the pool
becomes cooler, contraction of the liquid salt intensifies the chain reaction,
making the pool become hotter. A Molten Salt reactor will “load follow” (think
“cruse control”) over a surprisingly large portion of its power range.
Control rods can bring the reactor down to "idle". Total shut down
can be achieved in a few seconds by draining the fuel salt into the dump tanks.
4.
The first heat exchanger heats a second loop of clear non-radioactive
molten salt called "coolant salt" is used to safely carry the reactor's heat to
the outside world. Coolant salt then heats the second heat exchanger to
make steam to drive an electricity generator.
5.
Some types of molten salt reactors need a
“pool cleaner” (the
gray "Chemical Processing" module) system to keep the uranium concentration proper
by adding fresh fuel while removing the nuclear waste. With some thorium
types, fresh make-up thorium is added as needed for up to thirty years at which
time the fuel salt has to have its dissolved waste products removed.
6. If,
for any reason, the reactor gets too hot,
a freeze plug in the reactor tank’s bottom melts, causing the fuel-carrying
molten
salt to
drain away from the nuclear graphite rods down into passively air cooled dump tanks (blue) located
beneath the reactor. There, away from the graphite rods, the chain reaction ceases
and, if left long enough, the molten salt will cool sufficiently to solidify.
Heaters will be needed to re-melt the salt.
________________________________________________________________________________________
MAGIC TEAM: THORIUM-FUELED MOLTEN SALT REACTORS
MAGIC TEAM: THORIUM-FUELED MOLTEN SALT REACTORS
(We are talking about the basic THORIUM CONVERTER reactor that makes its own radioactive
fuel and then consumes it.)
From
here on, things just get better.
Once started with a small amount of radioactive uranium or plutonium, Molten
Salt reactors will continue to run on non-radioactive thorium by first
converting the dissolved thorium into radioactive uranium-233 and then
fissioning (breaking) that atom. These two reactions will happen naturally
and simultaneously when you get things right.
Thorium is found
everywhere,
is 4 times as common as all forms of uranium combined, and, used this way in liquid form, produces 250 times as much
heat energy in a
single reactor pass as
a solid uranium fuel rod. This means thorium heat will cost less than 1/8,000th as much as coal
heat. This also means, since so little is needed, we'll never consume all the thorium available on
Planet Earth. Today, thorium is simply a waste tailing of rare earth
mining.
HOW NON-RADIOACTIVE
THORIUM WORKS
HERE IS HOW
NON-RADIOACTIVE 232-THORIUM CAN BECOME RADIOACTIVE 233-URANIUM (Breeding Reaction)
AND THEN MAKE HEAT (Chain Reaction)
(From the Moir-Teller article.)
The cost
of a molten salt reactor boiler should be in the same ball park as less than
twice a coal
burning boiler. Being unpressurized, the molten salt reactor can be
made out of relatively thin metal - Hastelloy-N for corrosion resistance - and
the unpressurized steam generators are also inexpensive-to-make thin metal
"shell and tube" devices. Nuclear graphite is a semi-synthetic
material that can be made from coal. The
particular salt used is not damaged by radiation so should last forever. 3
feet of concrete will contain the reactor's radiation and concrete is cheap - we
make roads out of it. The Chinese began a thorium molten salt reactor development program
in late 2010.
http://en.wikipedia.org/wiki/Nuclear_graphite
Like the
hot water heater in your basement, molten
salt reactors do not need operators. They "load follow" over most of
their power range much like the cruise control in your car. This is
because when the fuel salt gets hotter than the set temperature, it expands,
thinning out the amount of thorium-232/uranium-233 fuel that can get near the
reactor's graphite core. This, in turn, reduces the amount of heat the
fuel salt can make. If the thermal load on the reactor increases and the
fuel salt becomes cooler, the fuel salt contracts, allowing more fuel to get
near the reactor's graphite core, causing additional heat to be produced.
This process is quick, taking only 10 seconds or less (molten salt reactors had
to be powerful and fast to be candidates for powering large airplanes).
Control
rods are present to bring the reactor down to an "idle." If, for some
reason the reactor must be turned off completely, it will be necessary to go
through a month-long "fissile fuel cycle" using some enriched uranium,
plutonium, etc., to re-start the conversion reaction that converts
non-radioactive thorium-232 into the immediately consumed radioactive
uranium-233 that actually makes the heat.
The type
of Molten
Salt reactor being advocated here for repowering coal burning boilers can
run on thorium 30 years flat-out by adding more non-radioactive thorium once a year. It produces
about 1% the hazardous nuclear waste of an equivalent conventional reactor.
At the end of 30 years it needs to have the fuel-carrying salt
purified (the salt that
circulates through
the reactor and first heat exchanger) and the reactor's graphite rods replaced -
then it's good to go again for another 30 years.
There appears to be no practical obstacle to vastly different sizes of Molten
Salt reactors.
A more
detailed introduction by a professional writer in a hurry.
MSR - The Thorium Paradigm .pdf
A
conservative
introduction.
http://energyfromthorium.com/joomla/index.php?option=com_content&view=article&id=64&Itemid=63
An
on-line Wikipedia article:
http://en.wikipedia.org/wiki/Molten_salt_reactor
http://en.wikipedia.org/wiki/Thorium_fuel_cycle
________________________________________________________________________________________
QUICK HISTORY OF
THORIUM-FUELED MOLTEN SALT REACTORS
QUICK HISTORY OF
THORIUM-FUELED MOLTEN SALT REACTORS
Born in
Cold-War secrecy, this reactor type was first developed as a nuclear aircraft engine
in the 1950s by Pratt and Whitney, test-stand run successfully, given multiple rides
in a B-36 bomber to get crew shielding right, and then abandoned by the U.S. military over the next decade
when thorium proved to have no military weapons value.
A ten
megaWatt Molten Salt Reactor was later built at Oak Ridge National
Laboratories. It ran well for about 5 years on both pure
and various blends of
thorium, uranium, and plutonium.
Solid
thorium fuel rods were used experimentally in the 1957 conventional 60 MWe "Shippingport"
reactor near Pittsburgh, PA, between 1977 and 1982.
http://en.wikipedia.org/wiki/Shippingport_Reactor (Right, Shippingport
reactor vessel.)
A 1,000
megaWatt (e) Molten Salt electricity generating unit was designed by EBASCO (a
consortium of 15 Midwest power companies) for Oak Ridge National Laboratories in
1965, and then shelved in favor of established conventional solid fuel
reactors.
The MSR
program had near-zero weapons value and was cancelled about 1974 when the government decided in favor of
funding liquid metal fast breeder reactors which could make far more weapons
material faster.
The liquid
metal fast breeder reactor program, in turn, was killed for nuclear proliferation
reasons in 1994 by an administration with strong anti-nuclear ties.
Czech Republic, France, China (molten salt reactor development,
large thorium deposits, small uranium deposits), India (solid thorium fuel rod
reactors, large thorium deposits), are
currently active in thorium energy research with Norway (large thorium
deposits), Japan, and Russia
looking on.
________________________________________________________________________________________
About using molten
salt as a coolant.
About using molten salt as a
coolant.
________________________________________________________________________________________
Nuclear Aircraft Engines 1946-1962
Nuclear Aircraft Engines 1946-1962
"Aircraft Nuclear Propulsion (ANP) Program",
Mid-1950s
Molten Salt Reactors (MSRs) - a type of Nuclear
Reactor
The most interesting application of molten salt
technology was the development of the Molten Salt (Nuclear) Reactor
(MSR). Originally developed to power a deep penetration bomber for
targets in the Soviet Union during the early Cold War (1946 - 1962),
it is a remarkable, yet virtually unknown reactor. Part of the problem
was the limited geographical experience of the MSR as both operating
MSRs were built only at Oak Ridge National Laboratory (ORNL), near
Knoxville, Tennessee, USA.
The first MSR was the 1954, 100-hour operation of the
Aircraft Reactor Experiment (ARE) at ORNL. Its sole purpose was to
demonstrate the then unheard of notion of operating a reactor at red
heat (~750°C; ~1,550° F) with a molten fuel and coolant consisting of
melted fluoride salts (sodium fluoride, NaF; zirconium fluoride, ZrF 4;
and UF4 [enriched in 235U]).
The second MSR was a
civilian power plant prototype, the Molten Salt Reactor Experiment
(MSRE)7.
Hugely successful, it was ignored by the US Atomic Energy Commission (US
AEC), which had decided to favor the Liquid Metal Fast Breeder Reactor (LMFBR).
The Director of ORNL, Dr.
Alvin Weinberg, pushed for the MSR, but was fired for his efforts.
The notable features of this reactor are:
● Meltdown proof
● Does not produce weapons grade plutonium
● Has inherent non-proliferation features
● Thousands of years of energy
● Simplified fuel cycle (no fuel elements nor reprocessing required)
● Its wastes are simpler and less toxic than current nuclear wastes
● Only hundreds of years of storage versus thousands for the current
wastes
● Can completely destroy military plutonium
● Can burn the existing wastes (spent fuel)!
● Higher thermal efficiencies (operates at a "Red Heat"; ~700° C [1,260°
F])
The above was written and created by
Bruce Hoglund
<bhoglund@earthlink.net.DoNotSpamMe>, © 1997
Please send me any HELPFUL comments. Responsible use is allowed as long as the
author is cited.
Above from:
MSR -
What is Molten Salt & Its Technology_ .pdf
(Right) In fact, there were
TWO nuclear aircraft engines under development at the time. Heat Transfer
Reactor Experiment - 3 (HTRE-3) is the large one above and on the left in
the small picture. It came from Pratt & Whitney. The other one,
HTRE-1
(later rebuilt as HTRE-2) was an air-direct-core-cooled General Electric design.
(Small image above from Wikipedia (click
on it for large image), large
image (above) taken by author Sept, 2010 from Idaho National Labs parking lot.)
"The US Aircraft Reactor
Experiment (ARE) was a 2.5 MW
thermal
nuclear reactor experiment designed to attain a high
power density for use
as an engine in a nuclear powered bomber. It used the molten fluoride salt
NaF-ZrF4-UF4
(53-41-6 mol%) as
fuel,
was
moderated by
beryllium oxide (BeO), used liquid
sodium as a secondary
coolant and had a peak
temperature of 860 °C. It operated for a 1000-hour cycle in 1954. It was the
first molten salt
reactor. Work on this project in the US stopped after
ICBMs made it obsolete. The designs for its engines can currently be viewed
at the
EBR-I memorial building at the
Idaho National
Laboratory." - -
http://en.wikipedia.org/wiki/Aircraft_Nuclear_Propulsion
For more information about the
airplane photos, see ASME web article:
http://www.asme.org/kb/news---articles/articles/nuclear/molten-salt-reactors
________________________________________________________________________________________
After
Nuclear Aircraft Engines
After
Nuclear Aircraft Engines
Molten-Salt
Reactor Experiment 1965 to 1969.
(Oak Ridge National Labs Photo from Kirk Sorensen's 2011 TEA talk slides.)
Notice the water-cooled pump motor. The 1,200°F reactor was so hot you
could take a photograph of it at night without a flash. Both the heat and
corrosiveness of the salt makes this a place to stay away from. EBASCO did
some unrecognized brilliant engineering and came up with a far better reactor
confinement cell design.
(Left) SHOW ME THE FIRE-HOT HEAT.
Molten salt-to-air heat exchanger running
full-blast. 1,200°F+ is the normal discharge temperature of this reactor.
It can replace most coal, natural gas, and oil fires. Molten salt reactor
experiment, Oak Ridge National
Laboratories.
Temperature Colors - 540.jpg
(Right) Assembling the graphite core of the
experimental 10
megaWatt Molten Salt Reactor (MSRE).
"The MSRE's piping, core vat and structural
components were made from
Hastelloy-N and its
moderator was a
pyrolytic graphite core. The fuel for the MSRE was
LiF-BeF2-ZrF4-UF4
(65-30-5-0.1), the graphite core
moderated it, and its secondary
coolant was
FLiBe (2LiF-BeF2),
it operated as hot as 650 °C (1,200°F) and operated for the equivalent
of about 1.5 years of full power operation."
From:
http://en.wikipedia.org/wiki/Molten-Salt_Reactor_Experiment
________________________________________________________________________________________
Dr. Ralph Moir and Dr.
Edward Teller (inventor of the Hydrogen Bomb) advocate MSRs
From leading nuclear experts:
Dr. Ralph Moir and Dr.
Edward Teller (inventor of the Hydrogen Bomb) advocate MSRs
MSR - Thorium-Fueled Underground Power Plant Based On Molten Salt
Technology - moir teller .pdf
(P-334, NUCLEAR TECHNOLOGY, VOL. 151, SEP. 2005)
This paper addresses the problems posed by running out of oil
and gas supplies and the environmental problems that are due to greenhouse gases
by suggesting the use of the energy available in the resource thorium, which is
much more plentiful than the conventional nuclear fuel uranium. We
propose the burning of this thorium dissolved as a fluoride in molten salt in
the minimum viscosity mixture of LiF and BeF2 together with a small amount of
235U or plutonium fluoride to initiate the process to be located at least 10 m
underground. The fission products could be stored at the same
underground location. With graphite replacement or new cores and with the liquid
fuel transferred to the new cores periodically, the power plant could operate
for up to 200 yr with no transport of fissile material to the reactor or of
wastes from the reactor during this period. Advantages that include
utilization of an abundant fuel, inaccessibility of that fuel to terrorists or
for diversion to weapons use, together with good economics and safety features
such as an underground location will diminish public concerns.
We call for the construction of a small prototype thorium-burning reactor.
(How this, Dr. Teller's last paper, came into being:
http://ralphmoir.com/media/moirtel.pdf )
MSR - Hatch Reid Introduce New Thorium Nuclear Fuel Bill to Promote Energy
Independence .pdf
"Edward
Teller had a different approach to nuclear safety. He thought that reactors
should be buried deep underground and operate without human intervention.
That way if the reactor broke, you could throw in a few shovels of dirt, and
that would be all it took to keep the reactor safe forever, or so Teller
thought. Towards the end of his life, Teller realized that Alvin
Weinberg's Molten Salt Reactor (MSR) was safe, and that if you built MSRs they
would not have to be buried so deep in order to protect the public. The
MSR was very stable, in fact so stable that no operators were required.
Since the reactor core was a molten fluid, you did not have to worry about
nuclear meltdown. Teller explained it all in his last paper,
Thorium fueled underground power plant based
on molten salt technology."
From:
http://nucleargreen.blogspot.com/2011/06/nuclear-industry-subsidies-part-iii.html
by Charles Barton
________________________________________________________________________________________
THE GOOD:
Molten Salt Reactor advantages
THE GOOD:
Molten Salt Reactor advantages
30-year
automatic power runs with a sealed reactor containment is claimed.
From: MOLTEN-SALT REACTOR CONCEPTS WITH
REDUCED POTENTIAL FOR PROLIFERATION OF SPECIAL NUCLEAR MATERIALS H.F. Bauman,
W.R. Grimes and J.R. Engel (Oak Ridge National Laboratory) H.C. Ott and D.R.
deBoisblanc (EBASCO)
* Note Added in Proof: Since this report was written, a
molten-salt system was identified that may be remarkably resistant to materials
diversion as well as having a conversion ratio near 1.0. This system uses a
denatured fuel mixture of 233U-238U;
processing consists only of removing fission products. These results are only
tentative and require more analysis before the described properties can be
confirmed. - -
" Molten Salt Converter Reactors with No On-Site Fuel Processing
Molten-salt reactors without continuous fuel processing (except
for fission gas removal) have been studied extensively. While not intrinsically
different from MSBRs except for processing, the conversion ratios for such
systems are generally less than 1.0 (typically 0.85 to 0.95) and they have
therefore been called molten-salt converter reactors (MSCRs). In the cases
studied, a fuel charge would remain in the reactor for either 6 or 8
equivalent full-power years (efpy), where the reactor lifetime is taken to
be 24 efpy, or about 30 years of operation at 0.8 plant factor. While the
operating cycle may be long enough to be of interest for a nonproliferation
reactor, the usual MSCR cycle requires continual addition of fissile fuel to
maintain the reactor critical. To meet the criteria of the non-proliferation
reactor, the MSCR would have to be modified to eliminate the need for fissile
feed and to provide another means for controlling the reactivity (keff). To
achieve these objectives, the initial charge could be modified to contain all
the fissile material required for the entire operating cycle. A good way to do
this would be to boost the conversion ratio to near 1.0 by increasing the amount
of thorium in the charge, which would also increase the amount of fissile
material required. This system appears to be quite feasible, and would not be
greatly different from at least one of the MSCR cases studied, in which a
lifetime averaged conversion ratio of 0.98 was obtained based on a fuel salt
containing 14 mole percent thorium.
The problem of controlling reactivity with adding or removing
fissile material also appears tractable. The largest change in reactivity occurs
during the first few months of the cycle, as the rapidly saturating fission
products build in. This change is suited to control by a burnable poison added
to the fuel charge. Reactivity changes would be small during the remainder of
the cycle and could be controlled by conventional shim rods in the core. The
fissile materials usually considered for the startup of molten-salt reactors are
fully enriched uranium, recycled plutonium from light-water reactors, and
recycled 233U from molten salt reactors.
The overall performance of the system is little affected by the
starting material, since (because of the high conversion ratio) after a few
years the main fuel in the system becomes 233U. For this reason, molten-salt
reactors have been examined as burners for the plutonium generated in
light-water reactors. The plutonium could be utilized without requiring the
fabrication of fuel elements, and with minimum requirements for plutonium fuel
transportation.
The performance of the non-proliferation system can be estimated
by comparison with appropriate cases from the MSCR studies. It was assumed that
the average conversion ratio for the non-proliferation system would be roughly
equal to the end-of-cycle conversion ratio for a comparable MSCR system, because
of the effect of the control poison required. For a reactor designed for an
average conversion ratio of 0.95, the estimated fissile specific inventory is
about 3 kg/MWe and the estimated lifetime (24 efpy) fissile requirement is about
1 kg/MWe. It is expected that this system could operate on an 8-efpy cycle,
which would require two fuel-salt changes during the life of the reactor. Thus
the fissile inventory that would be removed with the fission-product-laden salt
charge at the end of a fuel cycle would be approximately equivalent to that
installed with the new salt charge. Even longer cycles, such as 12 efpy
requiring only one salt change per lifetime, appear possible but would have to
be confirmed by further studies.
The diversion resistance of the MSCR-type system would be
approximately equivalent to the previously described systems with processing,
except that the reactor would have to be opened up under supervision one or more
times during its lifetime for replacement of the fuel salt."
Other advantages:
It is hot enough to replace every coal burning
boiler ever made.
It can be made large enough to replace every
coal burning boiler ever made.
It is more docile and predictable during power
changes than all solid fuel reactors since the fission product, xenon-135,
produced by all reactors, immediately bubbles out of the liquid fuel salt and
leaves the core's reaction area without causing the reactor to become "spooky"
as the xenon-135 decays away (it has a nine-hour half-life).
It can be made far more cheaply than today's
solid fuel reactors.
It gets far more energy out of its fuel than
today's reactors.
It can run on the world's nearly endless
supply of dirt-cheap thorium.
It is unpressurized so does not need a
containment vessel, just a nuclear "hot room confinement" shielding and sealing.
Its heat exchangers are virtually unpressurized
(except for perhaps 5 psig inerting) for
minimum cost, maximum safety.
It can be run at a average 80% capacity factor unattended for 30 years
except for an annual "Topping Off" of thorium.
Its negative thermal reactivity makes it an
excellent load follower and confers great safety.
________________________________________________________________________________________
THE BAD: Molten Salt Reactor shortcomings
THE BAD:
Molten Salt Reactor shortcomings
"If it sounds too good to be true, it usually
is." As an old project applications engineer, I've seen a lot of seemingly
good ideas (some of them mine) go sour.
To the author, the WORST THING ABOUT MOLTEN
SALT REACTORS IS HOW HOT THE SALT HAS TO BE BEFORE IT BECOMES MOLTEN:
459°C. or 858°F for the basic fuel salt, Li2BeF4 (Flibe).
This is dauntingly hot. Some metals will
become soft, or even melt, at temperatures like these. Fortunately, the
Nichrome wire used to get the pipes and pumps hot is good for 2,552°F but will
suck up a lot of Amperes
restarting a stone-cold MSR reactor
(52 Amps to get 1,000°F out of AWG 8 Nichrome).
On the other hand, the boiling point of
Li2BeF4 is 1,430°C, or 2,610°F, well above the 1,300°F
cruising temperature of a thorium reactor, provides a huge vapor pressure
safety margin.
The reactor's third cooling loop is a commercial heat
transfer medium, HITEC, for heating and cooling between 300-1100°F (149-538°C)
that is used in process operations, such as reactor temperature maintenance,
high-temperature distillation, reactant preheating, rubber curing, and
rotational molding.
1. To start the reactor, something
strongly fissile, such as uranium-235 at 20% enrichment is needed to initialize
the conversion of non-fissile thorium-232 to fissile uranium-233, far greater
than the 4% enrichment generally used for conventional solid fuel reactors.
20% enrichment is considered the threshold for weapons-grade material.
2.
MSR -
The Bad News from France .pdf As the (non-French speaking,
non-nuclear engineer) author understands this report, they claim you can get
into trouble with certain breeder reactor configurations and they have come up
with an even safer, better, faster, "Molten Salt Fast Breeder Reactor," a
no-graphite core fast neutron reactor optimized for breeding fissile fuels.
The author is talking about the
far more
mundane "Molten Salt Converter Reactor," a graphite-core slow
neutron reactor optimized for 30-year electricity power runs while making almost no
nuclear wastes.
Does anyone know of
criticality issues associated with thermal region converter reactors?
3. I have asked three different
persons who claim to be knowledgeable about Molten Salt Reactors if MSRs were
"ready for prime time." I have been met with silence
from all three.
4. Since salt is corrosive, Molten
Salt reactors and everything associated with them have to be made from the same
more expensive materials we use to make our salt-water nuclear aircraft carriers
and submarines. Materials such as
Hastelloy-N
(an anti-corrosive, radiation-resistant alloy),
brass, and expensive high-temperature plastics.
5.
The buildings in the
following sketches will have to be built for corrosion resistance and
corrosion containment. Notice the pumps in the salt-containing reactor and
steam generator buildings are above the salt
levels. Being at the highest point in a liquid loop makes them more cavitation-prone,
not a good thing.
6.
http://en.wikipedia.org/wiki/Operation_Teapot "MET" was an
atomic bomb with a core of
uranium-233. It was, in fact, detonated in this series of tests. "MET" had a
yield of 22 kilotons - in the same range as the Hiroshima and Nagasaki atomic
bombs. The nuclear weapon equivalent of a steam engine powered airplane.
7. Following from: ESTIMATED COST OF ADDING A
THIRD SALT-CIRCULATING SYSTEM FOR CONTROLLING TRITIUM MIGRATION IN THE lOOO -
MW(e) MSBR
ABSTRACT
"Controlling tritium migration to the steam system of the
1000-MW(e) reference design MSBR power station by interposing a KN03-NaNOa-NaN03
[HITEC] salt-circulating system to chemically trap the tritium would add about $13
million to the total of $206 million now estimated as the cost of the reference
plant if Hastelloy N is used to contain the LiF-BFa salt employed to transport
heat from the fuel salt to the nitrate-nitrite salt, and about $10 million if
Incoloy could be used.
The major expenses associated with
the modification are the costs of the additional heat exchangers ($9 million),
the additional pumps ($5 million), and the 7LiF-BeFa inventory ($4.8 million).
Some of the expense is offset by elimination of some equipment
from the feedwater system ($2 million), through use of less expensive materials
in the steam generators and reheaters (about $2 million), and through an
improved thermal efficiency of the plant (worth about $1 million).
In addition to acting as an effective tritium trap the third
circulating system would make accidental mixing of the fuel and secondary salts
of less consequence and would simplify startup and operation of the MSBR. A
simplified flowsheet for the modified plant, a cell layout showing location of
the new equipment, physical properties of the fluids, design data and cost
estimates for the new and modified equipment are presented." - - (From
ORNL-TM-3428)
_____________________________________________________________________________________
THE UGLY: When running,
thorium's U-232 radiation keeps terrorist's hands out of the cookie
jar.
THE UGLY: When running,
thorium's U-232 radiation keeps terrorist's hands out of the cookie
jar.
When
running, the molten salt reactor's fission process converts non-radioactive
thorium-232 into radioactive uranium-233. A trace amount of uranium-232 is
also produced. Uranium-232 produces a very strong gamma ray when it
decays. Eventually, only a trace amount - 1% - of any radioactive material
remains as the reactor runs out of fuel, but, while running, you can pick up a 5
rem dose (a significant dose) in a very few minutes if you go around the shielding and get near the
reactor.
Not
necessarily more, but different
radiation containment materials arranged in different order are needed to shield
molten salt reactors. The residual 1% is strongly radioactive at first but
soon decays to 17% in 10 years and eventually to the radioactivity level of
natural uranium ore in a mine after several hundred more years, eliminating the
need for million-year storage of the large amounts of high-level nuclear waste
our uranium nuclear power plants make.
Shoot-from-the-hip comment by someone who really
doesn't like liquid thorium reactors: (
MSR - Steve Bell's Objections to MSRs .pdf )
"The
obstacles to a molten salt liquid thorium reactor are more monstrous, as is
the concept itself. I find it hard (though not impossible) to envision a
nuclear reactor concept that more elegantly combines all the worst imaginable
industrial safety and health problems into one package. While there is too
little space here to elaborate, one difficulty is safely managing tons of
extremely radioactive molten materials at 1100°F being pumped through, into, and
out of the system. Leaks are inevitable and would not be benign events. Even
if you can get past such difficulties, there are enormous infrastructure
investments in new materials and manufacturing. Serious nuclear system
engineers will stay far away from this concept, now and forever." - - Steve
Bell, Friday, August 13, 2010, 12:34:12 PM
MSR - U-232 and the Proliferation-Resistance of U-233 in Spent Fuel - Kang and
von Hippel .pdf
"India's Department of Atomic Energy (DAE) has been concerned about the
occupational hazards associated with the fabrication of fuel containing U-233.
Its long-term ambition is to cleanse U-233 down to “a few ppm” U-232 using laser
isotope purification. In the meantime, a 1993 article from the Bhabba
Atomic Research Center in Bombay reported a 6.7 person-rem summed dose incurred
by workers fabricating a research-reactor core containing 0.6 kg “clean” U-233
containing 3 ppm U-232." (India is committed to thorium as a reactor
fuel.)
"Table 2: Unshielded working hours required to accumulate a
5 rem dose (5 kg sphere of metal at 0.5 m one year after separation).
Metal Dose Rate
(rem/hr)
Hours
Weapon-grade "fresh" plutonium
0.0013
3800. < (This shows how silly we are being
Reactor-grade "stale" plutonium
0.0082
610. about plutonium radiation. - - JH)
U-233 containing 1ppm U-232
0.013
380.
U-233 containing 5ppm U-232
0.059
80.
U-233 containing 100 ppm U-232
1.27
4.
U-233 containing 1 percent U-232 127.
0.04"
(Right) What is needed to stop different
kinds of radiation.
From Wikipedia:
"Thorium fueled reactors may pose
a slightly higher proliferation risk than uranium based reactors
because, while Pu-239 will fairly often fail to undergo fission after
neutron capture and produce Pu-240, the corresponding process in the
thorium cycle is relatively rare. Thorium-232 converts to U-233, which
will almost always undergo fission successfully, meaning that there will
be very little U-234 produced in the reactor's thorium/U-233 breeder
blanket, and the resulting pure U-233 will be comparatively easy to
extract and use for weapons. However, the opposite process
(neutron knock-off) happens as a matter of course, producing
U-232, which has the strong gamma emitter, thallium-208, in its decay
chain. These gamma rays complicate the safe handling of a weapon and the
design of its electronics; this explains
why U-233 has never been pursued for weapons beyond proof-of-concept
demonstrations."
The
above is a strong argument for a sealed 30-year reactor on a barge (below).
If something goes bad, the reactor barge goes back to the factory where
specialized equipment with proper shielding can be used to efficiently effect repairs. If
something doesn't go bad, after 30 years the reactor goes back to the factory
for either disposal or refurbishing, refueling, and reuse. - - Jim Holm
Over half of the 1,200 supersized power plants are on navigable
water, making shipyard mass produced concrete "Reactor Barges" a
cost-attractive approach. They would be parked on pilings in filled-in slips cut next to a
power plant’s turbine gallery. If desired, a great deal of physical security can
be economically added. Such "Reactor Barges" would act as catch basins in the
event of an accidental fuel salt spill, "float" on the ground during an earthquake, be
"high and dry" in the more likely event of a storm surge, be easily returned to
a factory for its 30-year refurbishing-refueling, and be easily removed forever
when no longer needed, leaving no residual radiation or nuclear power site
decommissioning costs.
_______________________________________________________________________
THE ROUGH SPOTS:
THE ROUGH SPOTS:
Out gassing of radioactive Xenon-135 and cesium something or
other. Nothing solid uranium reactors don't also do but gasses stay
trapped in the zirconium tubes that hold the fuel pellets. Xenon-135 makes
reactors "squirrely" and was a big reason the operators screwed up at Chernobyl.
Since the xenon-135 bubbles out of the water-like liquid salt immediately and
thus does not affect the reactor's fission strength, this is one more reason
molten salt reactors are well-behaved. A simple and inexpensive out-gas
handler was developed for the Molten Salt Experimental Reactor.
________________________________________________________________________________________
General Considerations
General Considerations
1. Simple elegance rather than mechanical precision.
"Unpressurized" is the word that makes this reactor and its
associated equipment far cheaper than equivalent solid fuel rod reactors.
A major disadvantage of MSRs is that the molten salt is
corrosive. The reactor system thus has to be made out of corrosion-resistant
materials such as
Hastelloy-N.
2.
Comment by Bruce Hoglund:
"There are no technical obstacles for the deployment of a
'sealed' MSR that operates with no chemical processing. Such a reactor
could operate for ~30 years with no processing other than allowing the noble
gases to naturally bubble out of the salt and periodic additions of fissile
material.
Since it would be advantageous due to environmental, economic,
and resource conservation concerns to achieve as much reclamation of the
expensive salt after (or during) the 30 year operation period, a parallel
development of various salt processing methods should occur
(78)
(much of which has already been done as part
of the Integral Fuel Reactor [IFR] project's fuel cycle studies). If this
strategy of attempting to remove very long term fission product buildups in the
salt is pursued, the salt can continue service in another reactor after the
first MSR has reached the end of its life.
This would not only greatly reduce decommissioning costs and
difficulties (as the vast majority of the radioactivities go with the salt and
removed fission products), but allow the expense of the salt to be amortized
over >100 year periods!"
78. Page 94, "Conceptual Design Characteristics of a Denatured Molten-Salt
Reactor With Once-Through Fueling", J.R. Engel, W.R. Grimes, H.F. Bauman, H.E.
McCoy, J.F. Dearing, & W.A. Rhoades, (1980), ORNL/TM-7207, 156 pages.
http://www.moltensalt.org/references/static/home.earthlink.net/bhoglund/multiMissionMSR.html
3. There is a fairly recent study on the estimated cost of electricity
from 1, Molten-Salt reactor powered plant, 2, conventional nuclear, and 3, coal.
MSR - Cost of electricity from Molten Salt Reactors - coe_10_2_2001.pdf
There have been no studies on what it would cost to produce electricity from a
plant converted from coal to MSR nuclear.
________________________________________________________________________________________
Uncertainties, unanswered questions
Relocated to:
Questions. Things I know
I don't know.
________________________________________________________________________________________
References
References
http://energyfromthorium.com/
Kirk Sorensen, is the
Molten Salt Reactor / LFTR's current
U.S. custodian. If you check out only one site . . .
MSR-FUJI - General
Information .pdf -
A quick presentation.
MSR Development in Japan .pdf
MSR -
What is Molten Salt & Its Technology_ .pdf
MSR - HITEC Heat Transfer
Salt .pdf
MSR Thorium Mining in Turkey - amr-thorium-project-2011.pdf
There is a book available from Amazon on how the
heat exchangers were designed to be fabricated (by R.G. Donnelly, $9.99). The
inexpensive "shell and tube" heat exchangers to make the steams necessary to replace the coal boiler could
come from Babcock & Wilcox or perhaps 50 other boilermakers worldwide.
Heat Exchangers - Classification of Heat Exchangers - 0471321710 .pdf
Why did our nuclear industry pass on
this one? While the MSR is not perfect, consider all the shortcomings of
what we have now.
This is the "Model T" of nuclear reactors. Intended to
replace coal right from the start and safe versions are easy to build in any size. It is the low-cost
nuclear replacement for all large coal fires.
The mitigation money to pay for them for them is there. The
proof-of-performance prototypes have been run. The design studies for 350
and 1,000 megaWatt (electrical) operational units have been worked out.
All we need now are site, construction, and shop detail drawings and the courage to actually
do it.
http://home.earthlink.net/~bhoglund/mSR_Adventure.html
________________________________________________________________________________________
Molten Salt
Reactor Basics
The yellow fuel-carrying salt is
shown flowing into and out of the reactor in tubes drilled in an otherwise solid
block of graphite (colored black) - about 90% of the volume of the reactor
vessel is occupied by graphite.
Molten Salt
Reactor Basics
It cannot melt down because being melted
is its normal state. Being an unpressurized pool of molten salt, it
can't explode. If, for any reason, the salt gets too hot, a freeze plug in
the bottom of the reactor melts and the liquid "fuel salt" drains into
the blue emergency
dump tanks beneath the reactor. There, away from the reactor's moderator
rods, the fuel salt immediately ceases to fission and is passively cooled by a
sodium-potassium cooling system.
The neat thing about using molten salt is that if
any leaks out, it immediately cools, turns solid, and doesn't go anywhere -
think red-hot lava flowing from a volcano.
The second stage "Coolant Salt" is non-radioactive, clean, pure melted
salt - also as fluid as water - with no radioactivity. This is the salt
that carries the heat from the reactor to the "shell and
tube" heat
exchanger (lower right, above) to make the steam needed to drive the turbine which, in turn, drives
the electricity generator.
The "Chemical Processing" module is a small "hot" room
located next to the reactor. It functions like a swimming pool cleaner - spent
nuclear fuel is removed, fresh fuel is added.
The reactor has an
extremely high negative temperature coefficient and tends to "load
follow" (think cruise control) extremely well so thorium reactor experts
say only a few control rods will do. (Image from Idaho National Laboratories Gen-IV Reactor
Project.)
________________________________________________________________________________________
More about Molten
Salt Reactors
More about Molten
Salt Reactors
http://energyfromthorium.com/
Kirk Sorensen - More than anyone is the LFTR's current
custodian.
http://www.energyfromthorium.com/pdf/ Kirk Sorensen has provided us
with a gold mine of information.
http://www.asme.org/kb/news---articles/articles/nuclear/molten-salt-reactors
http://en.wikipedia.org/wiki/Molten-Salt_Reactor_Experiment
http://en.wikipedia.org/wiki/Molten_salt_reactor
MSR - Safety and Licensing Aspects of the Molten Salt Reactor - 120507.pdf
Molten-Salt-Reactor
Technology Gaps .pdf
MSR - High Temperature Molten Salt Coolants - Literature-IAEA .pdf
MSR - Thermal and Fast Spectrum Molten Salt Reactors -
msr_deliverable_doe-global_07_paper.pdf
http://home.earthlink.net/~bhoglund/ Bruce Hoglund Home page
http://www.moltensalt.org/ Bruce
Hoglund
http://www.moltensalt.org/references/static/home.earthlink.net/bhoglund/multiMissionMSR.html
Thorium Molten Salt Reactor covered in Wall Street Journal
The 1965 and
1972 engineering projects for producing a 1,000 megaWatt (electrical) liquid
reactor.
Molten salt reactors -
As per World Nuclear Association
During the 1960s, the USA developed the molten salt breeder reactor concept
as the primary back-up option for the fast breeder reactor (cooled by liquid
metal) and a small prototype 8 MWt Molten Salt Reactor Experiment (MSRE)
operated at Oak Ridge over four years. U-235 fluoride was in molten sodium and
zirconium fluorides at 860°C which flowed through a graphite moderator. There is
now renewed interest in the concept in Japan, Russia, France and the USA, and
one of the six Generation IV designs selected for further development is the
molten salt reactor (MSR).
In the MSR, the fuel is a molten mixture of lithium and beryllium fluoride
salts with dissolved enriched uranium, thorium or U-233 fluorides. The core
consists of unclad graphite moderator arranged to allow the flow of salt at some
700°C and at low pressure. Heat is transferred to a secondary salt circuit and
thence to steamo.
It is not a fast neutron reactor, but with some moderation by the graphite is
epithermal (intermediate neutron speed). The fission products dissolve in the
salt and are removed continuously in an on-line reprocessing loop and replaced
with Th-232 or U-238. Actinides remain in the reactor until they fission or are
converted to higher actinides which do so. MSRs have a negative temperature
coefficient of reactivity, so will shut down as temperature increases beyond
design limits.
Liquid Fluoride Thorium Reactor
The Liquid Fluoride Thorium Reactor (LFTR) is one kind of MSR which breeds
its U-233 fuel from a fertile blanket of liquid thorium salts. Some of the
neutrons released during fission of the U-233 salt in the reactor core are
absorbed by the thorium in the blanket salt. U-233 is thus produced in the
blanket and this is then transferred to the fuel salt. LFTRs can rapidly change
their power output, and hence be used for load following. Because they are
expected to be inexpensive to build and operate, 100 MWe LFTRs could be used as
peak and back-up reserve power units.
Fuji MSR
The Fuji MSR is a 100 MWe design to operate as a near-breeder and being
developed internationally by a Japanese, Russian and US consortium. The
attractive features of this MSR fuel cycle include: the high-level waste
comprising fission products only, hence shorter-lived radioactivity; small
inventory of weapons-fissile material (Pu-242 being the dominant Pu isotope);
low fuel use (the French self-breeding variant claims 50kg of thorium and 50kg
U-238 per billion kWh); and safety due to passive cooling up to any size.
________________________________________________________________________________________
Advanced LIQUID FLUORIDE
THORIUM (LFTR) Nuclear Reactors
Advanced LIQUID FLUORIDE
THORIUM (LFTR) Nuclear Reactors
The following advanced MSR
versions are not suitable/intended for the author's idea for repowering an existing
superheated or supercritical coal, natural gas, or oil burning steam
driven electricity generating station.
(Right)
A proposed 200 mWe Thorium powered power plant. For
more, visit:
http://itheo.org/articles/itheo-presents-ithems
These folks have gone beyond steam turbines to
gas turbines in their designs. There are some good reasons for this.
A big reason is that molten salt reactors and water don't get along too well and
need an additional buffer cooling loop which raises costs and lowers both
efficiency and reliability. See Gen-IV gas turbine diagram below.
The author notes that gas turbines are not all roses either. Note that it
has a power-sucking 2-stage gas compressor. Does this really make it that much better than
conventional superheated steam without smokestack losses? It does avoid
that third stage of heat exchanging - sort of - but you still have that
recuperator and intercooler.
Take a close look at the MSR-Gas Turbine
below. One might consider the gas turbine's
precooler and intercooler pair and the
steam plant's steam condenser a wash. - Grumpy old retiree.
Advanced LIQUID FLUORIDE
THORIUM (LFTR) Nuclear Reactors
http://energyfromthorium.com/
Kirk Sorensen - More than anyone is the LFTR's current
custodian.
http://www.energyfromthorium.com/pdf/ Gold mine of information.
http://msr21.fc2web.com/English.htm International Thorium Molten Salt
Forum (Japanese)
http://www.energyfromthorium.com/FluidFuelReactors.html Excellent
Primer on Aqueous Reactors (1958)
http://thorium.mine.nu/UCTEA/Technical_Readings.html Technical Papers
and Readings
http://en.wikipedia.org/wiki/Fuji_Molten_Salt_Reactor
http://www.ithems.jp/e_purpose.htm
http://itheo.org/articles/itheo-presents-ithems
Links
http://nucleargreen.blogspot.com/2010/07/fuji-project-seeks-300-million-in.html
http://home.earthlink.net/~bhoglund/
http://www.ltbridge.com/company
http://www.world-nuclear.org/info/inf62.html
http://thoriummsr.com/
Thorium a Viable Option .pdf
Thorium Based Fuel Options for the Generation of Electricity -
31030535.pdf
Thorium fuel cycle - Potential benefits and challenges - TE_1450_web.pdf
Thorium fuel utilization - Options and trends - te_1319_web.pdf
Thorium Proponent Kirk
Sorenson .pdf
________________________________________________________________________________________
Here is the modern PhD's dream for thorium-fueled
molten salt reactors.
A power plant that does not boil water - something man has had to do for 300
years to get mechanical energy from heat.
This power plant heats a gas such as helium and, on paper, should be 5% to 10%
more efficient than molten salt boiler steam power plant.
Hitting the Sound Barrier: Turbines are speed-of-sound sensitive devices and the
speed of sound in helium is about twice as fast as the speed of sound in steam.
Remember inhaling some helium from a helium balloon and then talking like a
chipmunk? These turbines are going to be difficult to build and maintain.
________________________________________________________________________________________
Websites by thorium
enthusiasts
http://nucleargreen.blogspot.com/
Charles Barton - It
is his father's reactor.
http://energyfromthorium.com/
Kirk Sorensen - More than anyone, the LFTR's current
custodian.
http://www.thoriumenergyalliance.com/
http://www.thoriumenergy.com/
http://www.thorium1.com/
http://www.ltbridge.com/
http://thoriumsingapore.com/content/
http://msr21.fc2web.com/English.htm
http://torium.se/ Thorium Electro Nuclear
Ltd.
http://www.kiae.ru/e/engl.html
http://www.thorenergy.no/ Norway
________________________________________________________________________________________
Small Particle Accelerator Could Power
Thorium Reactors.
Popular Science (6/16, Boyle) reports on the Electron Model of Many
Applications, or EMMA, "a small particle accelerator that could be used to power
future thorium reactors." The article notes that thorium is drawing increased
interest as the basis for reactors because of its safety in comparison to
traditional nuclear reactors. Getting thorium to release energy "is one obstacle
to building small thorium reactors," an issue EMMA could resolve. Popular
Science notes, "EMMA is the first non- scaling, fixed-field,
alternating-gradient (NS-FFAG) accelerator, qualities that make it easier to
operate and maintain, more reliable and compact, more flexible and more
efficient, according to British researchers."
Market Qualms Make Safer Reactor
Designs Slow In Coming, Experts Say.
In an "Ingenuity Of The Commons" blog entry for Forbes (4/22), Jeff McMahon
wrote, "Safer nuclear reactors have been available for years, but the energy
market prefers less expensive conventional designs, a nuclear energy expert from
Argonne National Laboratory said Thursday." Argonne Nuclear Energy Division
director Hussein Khalil said that there is a "tremendous incentive" to develop
"new reactors that have more inherent, intrinsic safety features, and we've been
doing this for some time at ANR" and while they have "been developed to a fairly
high degree of technical maturity, but none of them have been successfully
commercialized yet because it appears they can't yet compete on an economic
basis with the existing technology." Khalil said, "liquid-metal and sodium
cooled reactors are examples of safer reactor designs," but noted they haven't
been selected because it's easier and cheaper to repeat older designs than risk
the "'regulatory uncertainty' faced by power companies that risk new designs."
________________________________________________________________________________________
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