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● The Conventional Reactor Low Temperature Problem ● The Coal Yard Nuke Reactor ● Mass-Produced Reactors ● Costs
Example Project
This is a design exercise only! There are no actual plans to do this. This is just a drill.
Converting the "Big Bend" power plant from coal to nuclear.
Some things to consider.
The "Coal Yard Nuke Boilers Project" sections:
Why nuke our existing power plants? 1. Fast 2. Cheap 3. Effective --- Why not? They got us into this Climate Change mess.
Big Bend - Nuking an existing coal-burning power plant --- Almost step-by-step instructions.
Why we have to use high temperature nuclear reactors ---- Why conventional nuclear reactors won't work.
The reactor silos: What they are like and how they work --- Think farm silos.
The Coal Yard Nuke Reactor The Coal Yard Nuke Conversion Pebble Bed Reactor --- (Article Still Under Construction)
Who is making and selling pebble bed reactors --- Becoming a commercial item in some countries.
Costs: ----------------------------------------------------------------------------------------------------------------- What do we know and how do we know it?
How the reactors would be installed and connected --- Re-using the coal yard.
J R Whiting - A small one-reactor demonstration project. --- On the western shore of Lake Erie, just north of Toledo and south of Fermi II near Monroe.
Project Merlin: A 3 to 5 Year Plan
Taking advantage of the lessons learned in the computer world. --- How to drive quality up while driving cost down.
Mass producing pebble bed reactors for the world's power plants. --- Think assembly line 'Coal Yard Nukes' from perhaps 6 different countries.
Mass producing pebbles and prisms. --- Pebbles are silicon, so think high-tech brick factories, located in perhaps 20 different countries.
HTR-10 - Mass producing the pebble bed reactor builders and operators. --- China's Tsinghua University's teaching reactor is in operation.
E Bonds to Pay For Coal Yard Nukes --- Unlike World War II "E" bonds, this time the "E" will stand for "Environment"
Three other ways we can eliminate substantial amounts of CO2 --- We can knock another 20% off our CO2 production by changes in other areas.
Technically Speaking Sections: Top
Listing of High Temperature Gas Reactor Technical Documents --- Includes Uranium Information Center references on thorium.
The Hard Truth about Energy. --- You can't win, you can't break even, and you can't quit the game.
The famous thermodynamic idiot Amory Lovins advocates quitting by thinking in "Negawatts" - a great idea if you don't think about the consequences. Turning off, rather than cleaning up, the engines that power the world humans must have to survive is the path of suicide for both modern nations and the world itself in the face of ever-intensifying Global Warming.
If we don't clean up the engines, nature will not get the chance to heal herself and many will die. If we turn the engines that keep us alive off, most of us will soon die.
Cars, Trucks, Airplanes, and Trains --- Where their energy goes.
The Diminishing Returns Of Increasing Efficiency. --- Spending a lot more to get a little more.
Learn More About Nuclear Power Quickly. Selected Single Page Briefings: Top
http://en.wikipedia.org/wiki/Nuclear_energy Nuclear energy's roots. Where it all starts.
http://en.wikipedia.org/wiki/Nuclear_power Nuclear Power Plants
http://en.wikipedia.org/wiki/Enriched_uranium Uranium Enrichment
http://en.wikipedia.org/wiki/Nuclear_fuel_cycle The nuclear fuel cycle
http://en.wikipedia.org/wiki/Breeder_reactor Making all the nuclear fuel we can use forever.
http://en.wikipedia.org/wiki/Radioactive_waste All the different kinds of radioactive waste
http://en.wikipedia.org/wiki/Spent_nuclear_fuel Spent Nuclear Fuel or "Nuclear Waste"
http://en.wikipedia.org/wiki/Nuclear_reprocessing Spent nuclear fuel (nuclear "waste") recycling
_____________ End Of Technical Details Page Subject Section Index ____________
Example Project
This is a design exercise only!
Converting the "Big Bend" power plant at Apollo Beach, Tampa Bay, from coal to pebble bed nuclear.
Note: I have chosen to use Big Bend as an example because it is an excellent example of the generator size - 450 megaWatts - that will have to be converted worldwide. As far as I know, no one has ever discussed actually doing anything with Big Bend. This is a design exercise only! Again, a demonstration facility using a single 100 megaWatt generating unit must be built and test-run first before anything as large as Big Bend would even be contemplated.
Why nuke our existing power plants? 1. Fast 2. Cheap 3. Effective Top
Existing power plants are already wired to our cities - (NO NEW TRANSMISSION LINE RIGHT-OF-WAYS NEEDED), usually have ample land for several additional future units - (NO NEW LAND NEEDED), already have access roads - (NO NEW RIGHT-OF-WAYS NEEDED), already have railroad tracks - (NO NEW RIGHT-OF-WAYS NEEDED), and already have cooling water - (NO NEW RIPARIAN RIGHTS NEEDED) - no new construction delays or costs - they are already running! Talk about recycling! The confluence of so many essential power plant resources at one location means that the chances are very good that eventually there will be a 'big breeder' nuclear power plant at that site after the fossil fuel plant is worn out. This is one of those ideas that's as green as Geico's gecko.
The key to keeping both time and cost to a minimum is to make as few changes as necessary. Locate the conversion reactors away from the fossil fuel plant as far as possible. The penalty for doing this is long supercritical water lines. The benefit is there will be no changes to the existing plant other than the new steam generator and its feedwater and steam line tie-in points and the plant could continue to run on its original fossil fuel.
If we built nothing but new nuclear, what would we do with all the existing fossil-fuel burning power plants we now have? This is a major economic and grid logistics question no one is asking. Most important in the much less wealthy second and third world.
There are over 1,000 major conventional coal-burning plants with over 5,000 big boilers in the United States alone. Industry is lobbying the government to "Grandfather" these existing fossil-fuel plants, allowing them to continue to make CO2 pollution for up to 50 more years. Do you really want that? Worldwide, it's 130,000+ boilers in 50,000+ power plants in 225+ countries. Most of them are like J. R. Whiting where one pebble bed reactor has enough power to drive all the generating units in the entire plant.
Otherwise, we'd need to build 200+ MORE large nuclear power plants in addition to our existing 104 medium nukes to completely eliminate power plant coal burning in the United States. Another hazard we would be walking into by building nothing but new nukes is that we would wind up with a much more highly centralized electrical system with fewer, but larger, generation points. We would loose even more grid diversity as existing coal-burning plants are closed down. A sure recipe for more frequent huge blackouts.
The 1,000+ coal-burning power plants we now have will soon be joined by another 100 to 150 additional new super-size coal-burning plants that are under way in the governmental approval process. In my humble opinion, new CO2-emitting coal and natural gas power plants should be outlawed immediately and only new conventional nukes built instead. Approximately 35 new nukes are also being talked about but the government is moving very slowly on approving them in spite of the fact they are superior in every way to what we have on-line now. Conventional and breeder nukes are what the future demands to prevent new Climate Change problems in the future. Coal burning should never, ever, be allowed again anywhere in the world.
The "Coal Yard Nukes" being advocated on this web site apply only to existing fossil-burning power plants because they are the fastest and least expensive way to remedy the Climate Change situation. Coal Yard Nukes will enable us to complete the service life of existing power plants at reasonable cost while also ending the major part of the Climate Crisis. Additional units of the Coal Yard Nuke type should be built along side the converted fossil fuel units where possible to quickly expand our generation capacity to enable conversion of our CO2 producing industrial, commercial, and residential coal, natural gas, and oil heating systems to electricity. Example: The coal being burned to produce ethanol from corn.
Keep in mind that coal and natural gas are our future oil, far too precious to burn just to make electricity and CO2.
"Coal Yard Nukes" is audacious plan. But we both know it will work.
Again: Every coal burning power plant in the world has ample space in its coal yard for small nuclear boilers. Let's take advantage of that fact.
Nuking existing fossil-burning power plants is more than a good idea. It's also a damn good environmental science project idea. It's a CO2 mitigation project that has excellent scientific value in that easily trackable data on a significant CO2 change will be generated. The data collected should vastly improve the quality of environmental computer models as more and more fossil-burning plants stop emitting CO2 over a several year time span.
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"Big Bend" - Nuking an existing coal-burning power plant: Top
Note: As a "bogey" reference for a typical modern coal-fired power plant, I picked the 4-unit TECO (Tampa Electric Company) "Big Bend" 1.8 GigaWatt plant located on the Alafia River near Apollo Beach, Florida, in the Tampa South Bay region. It's equipped with state-of-the-art emissions controls. Big Bend is unusual in that a reverse-osmosis desalination plant that supplies 25% of the area's fresh water is also located on their site. The Big Bend site has become a wildlife refuge for manatees that winter in the plant's warm discharge water. TECO also operates a super-high-efficiency, low-emissions combined cycle plant in nearby Polk County - only one of several in the entire country in addition to their lower CO2 emissions gas-fired Bayside plant (natural gas produces only 2/3 the CO2 of coal). TECO's current electricity mix is: Purchased Power 13%, Oil & Gas 35%, and Coal 52%. Through this engineer's eyes, TECO is a world-class operation. According to the press, TECO is experiencing a 150 megaWatt increase in electricity demand every year.
Three of Big Bend's four boilers are 445 MWe (MegaWatts electric) Riley Turbo® opposed wall-fired, wet-bottom coal units, and one is a 486 MWe Combustion Engineering tangentially fired coal unit. Typically, the boilers are designed for a safe drum operating pressure of 2,875 psig and can produce 2,868,000 lb/hr of steam continuously at 2,600 psig and 1,000°F at the superheater outlet when supplied with feedwater at 487°F at the economizer inlet. The steam outlet temperatures of the superheater and high temperature reheater are both 1,000°F, and the pressures are 2,600 psig and 552 psig, respectively.
The boilers are fired with low-sulfur bituminous coal. Everything running flat-out for a year might burn 6.4 million tons of 25 million BTU/Ton coal, or 17,000 tons of coal per day at 33% efficiency. http://www.tecocoal.com/COpremier.html - TECO's Elkhorn coal mine near Myra, Kentucky. At average coal spot prices spring 2007 of $35/ton, 6.4 million tons = $224 million per year. That much energy is about the same as 2 days worth of oil for the entire United States.
How much CO2 can a plant this size make? I don't have official figures but can use some government data (http://tonto.eia.doe.gov/FTPROOT/environment/co2emiss00.pdf ) to come up with an educated guess. They say a well-running coal-burning power plant produces about 2 pounds of CO2 for each kiloWatt hour of electricity it generates. So, using that rule-of-thumb:
Adding up Big Bend's 4 boilers comes to about 1,800 megaWatts electrical = 1.8 *103 megaWatts = 1.8 *106 kiloWatts;
1.8 *106 kW * 8,760 hours / year = 15,768 *106 or about 16 *109 kiloWatt hours / year.
At 2 pounds of CO2 per kWh, that's 32 *109 pounds of CO2 or 32 billion pounds of CO2 per year.
Converting to tons: 32 *109 pounds CO2 per year / 2 *103 pounds per ton = 16 *106 tons of CO2 per year is the maximum possible.
This is 16 million tons of CO2 per year or about 44 thousand tons of CO2 per day maximum.
According to CARMA, it ACTUALLY AVERAGES 30 thousand tons of CO2 per day.
A 6.3 pound gallon of gasoline produces about 20 pounds of carbon dioxide. Good Explanation: http://www.fueleconomy.gov/feg/co2.shtml
I read somewhere a large power plant like Big Bend makes as about much CO2 as 4 MILLION automobiles.
How can the weight of the CO2 in the air be greater than the weight of the fuel? Burning is the process of attaching two oxygen atoms from the air to a carbon atom from, say, coal to make a molecule of carbon dioxide (a molecule is a bunch of atoms http://en.wikipedia.org/wiki/Molecule ). This process is exothermic or, the process releases heat - which is why we did it in the first place. A carbon atom has an atomic weight of 12. When burned, two oxygens, each of which have an atomic weight of 16, become attached to each carbon atom, so the total weight of a CO2 molecule is 12 + 16 + 16 or 44.
http://www.tecoenergy.com/news/powerstation/bigbend/ Visit TECO's Big Bend plant and the other plants mentioned on TECO's web site.
TECO, Consumers Energy, Westinghouse, Combustion Engineering, Riley, ESKOM-PBMR, and General Atomics have nothing to do with this paper. They are entirely unaware I am using their plants and products as "concrete" examples in my advocating the principle of converting coal-burning power plants to nuclear power.
Technically Speaking: A Watt (W) is a basic unit of energy as is a British Thermal Unit (BTU). You will see both MWe (MegaWatts electric) and MWt (MegaWatts thermal) a lot when reading about power plants. Three MegaWatts thermal usually gets you about one MegaWatt electric because power plants are about 33% efficient. When you see a thermal device like a boiler rated in MWe, just multiply by three to approximate its wattage or 10 to approximate its BTUs. Remember also that one Watt-hour equals 3.41 British Thermal Units (BTU). A BTU is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. In electrical terms, a Watt is defined as the energy passing through a 1 Ohm resistor when energized by 1 Volt or, 1 Volt-Ampere. This is important because the electric company charges you by the Kilo Watt-hour or KWh.
It's "Errors and Omissions" time.
Please, everyone, let me know what is wrong with my plan. Or, if you know
of a better idea, let me know about it also. You can always
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Everything needed to convert fossil-burning power plants has been developed.
Why we can't use conventional nuclear reactors: Return To "Coal Yard Nukes" Index Top
THE MAIN PROBLEMS:
1. Today's Conventional Nuclear Reactors are often three or more times more powerful than today's fossil fuel boilers.
2. Fossil Fuel and Conventional Nuclear Reactor power plants operate in different steam temperature-pressure domains.
Fossil fuel boilers produce "SUPERHEATED" (dry) steam - typically 1,000°F, with typical pressures around 2,600 psi (1,500 BTU, 0.30 Ft3 per pound).
Conventional nuclear reactors produce "SATURATED" (wet) steam - typically 550°F, with typical pressures around 1,000 psi (1,200 BTU, 0.45 Ft3 per pound).
(For further discussion of the steam temperature compatibility problem and why conventional reactors can't be used, see end of this section)
These temperatures and pressures are way out of a conventional reactor's league and taking on these very hot monsters with a pebble bed reactor will be a challenge, not so much from a temperature standpoint, but, rather, from the enormous volume of heat the pebbles will have to deliver. "King Coal" can give even nuclear energy a very good run for the money. Most of the world's fossil fuel steam plants are of the smaller superheated type.
If we were to use a conventional reactor to power a coal-burning power plant, we would have to by-pass the high pressure stage of the turbine array, giving up about 1/3 of the electricity generating capacity of the power plant. Unacceptable, especially in a time of national electricity shortages while facing additional air conditioning, plug-in hybrid automobiles, and water desalination loads.
FOSSIL FUEL CAN EASILY PRODUCE A 2,000°F FLAME - that's "Hard Workin' Heat" and a good reason to like 'Old King Coal' a lot.
Several different Very High Temperature Reactors (VHTRs) with core temperatures that go above 1,800°F can replicate a fossil fuel fire.
The Very High Temperature Reactor (VHTR) choice, Pebble Bed reactors and their siblings, the Prismatics, being Doppler-Broadening temperature limited, are safe, simple, and completely developed reactor types that can deliver great volumes of heat at over 1,800°F. Both have a very high level of inherent safety, including a strong negative temperature coefficient whereby fission slows as temperature rises - a natural result of the Doppler Broadening effect. While the reactors themselves are less expensive, the Pebble and Prism fuels are more expensive for the heat they provide and will never be quite as cheap as conventional nuclear fuel. http://en.wikipedia.org/wiki/Pebble_bed_reactor and http://en.wikipedia.org/wiki/Gas_turbine_modular_helium_reactor
Further details of the steam temperature compatibility problem:
Superheated steam is steam hotter than 708°F (one of those magic water temperatures, like 32°F, and 212°F). Above 708°F, steam behaves like a dry gas, and, being dry, contains no water micro-droplets that cause erosion of the generator turbine blades. Conventional nuclear reactors use much greater volumes of steam to compensate for their lower temperatures (about 550°F) and pressures (about 1,000 psi) along with a "steam dryer" to protect their turbine blades. http://en.wikipedia.org/wiki/Boiler http://en.wikipedia.org/wiki/Steam_drum
1,000+ psi reactor steam pressures are why reactors are kept in "containment" buildings to keep radioactive particles from escaping in the event of a steam explosion. While a steam explosion is always possible any time you have high pressure steam, nuclear reactors lack the ability to make nuclear explosions. Nothing can contain a nuclear explosion. The explosion of your neighborhood fossil fuel power plant superheated steam boiler is of no public consequence.
Again. Conventional nuclear power plant reactors all produce steam temperatures that max out at about 550-600°F. That isn't hot enough to replace the 1,000+°F superheated steam produced by all modern fossil-fuel fired boilers and needed by their turbine-generators which have a high-pressure stage designed to run only on superheated steam.
So, you can't power your neighborhood fossil fuel power plant with your neighborhood nuclear reactor.....
About Superheated steam: http://en.wikipedia.org/wiki/Steam Steam. http://en.wikipedia.org/wiki/Superheater Steam engines. http://en.wikipedia.org/wiki/Steam_engine http://en.wikipedia.org/wiki/Steam_turbine Steam turbines are commonly used in power plants.
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The reactor silos. What they are like and how they work: Top
Water is a wonderful way to turn heat energy into mechanical energy because when you turn water into steam, it expands its volume 1,600 times. If steam is not allowed to expand in volume, its pressure will go up drastically. That's where all that piston-pushin power in a steam locomotive comes from.
Below: How a pebble bed steam boiler power plant is set up. Compared to conventional nuclear, pebble nuclear silos would be considered 'light.'
Pebble bed reactors are much better suited for "load following" than conventional reactors and should approximate a coal boiler's load following abilities in a superheated steam application. Steam control for load following (not shown in this drawing) will come from a computer coordinated feedwater throttle valve, a variable-speed "reactor gas circulating blower", a variable steam generator (boiler) gas bypass valve, and some bypass piping to return the hot gas directly to the reactor. Temperature and flow sensors to keep the computer and the operator informed of how things are going are also necessary. To repeat, strange as it sounds, running the hot gas directly back into the bed of pebbles and making them even hotter causes pebbles to reduce their atomic activity. Doppler Broadening (a nano-technology phenomenon if there ever was one) will make pebbles go toward, but not quite to, zero atomic activity as they approach their "hot idling" temperature. (A retrofit to an existing coal-fired plant might also show an economizer http://en.wikipedia.org/wiki/Economizer .)
Because pebbles are so hot, a gas - usually helium, nitrogen, or carbon dioxide - is used to carry the pebble's heat to the power plant's steam boiler. Water's supercritical temperature - where it stops behaving like a vapor and begins behaving like a gas - is around 700°F.
Inlet temperature of a pebble bed reactor is about 950°F, and its outlet temperature is almost 1,700°F. That duplicates the 1,000°F superheated steam produced by coal fire while running the pebbles in their thermal "sweet spot."
Note: The pebble bed power plant shown in the
drawing is set up as a
conventional coal-fired superheated steam boiler power plant. 750°C
= 1382°F, 530°C = 986°F, 250°C = 482°F, 35°C = 95°F, 25°C = 77°F.
I suspect this drawing may have been inspired by
the now decommissioned German
BOILERS: Modular pebble bed reactors were designed from the start to be inexpensively mass-produced in factories and shipped in standard shipping containers. There could be a variety of boiler types but current fossil-heated designs may be best for rapid power plant conversion - since speed, rather than efficiency is the most important issue. Boiler design will depend upon whether the boiler has reheat stages in addition to the typical drum with superheater stages. A supercritical pressurized water system, much like a conventional PWR reactor, but at supercritical temperatures and pressures is also a possibility since we have working temperatures as high as 1,700°F.
The German THTR-300 thorium pebble bed (above) had a boiler (actually, a ring of small boilers) designed for steam but they used helium pressurized to about 1,300 psi instead at low or no pressure to carry the heat from the pebbles to the boiler. In a fossil-fuel burning plant, these velocities are determined by the combined efforts of the forced draft and the induced draft blowers. While boiler design and fabrication is a routine heavy industry activity involving at least several months, the first pebble bed heated supercritical water heater will likely take more design and fabrication time since doing anything the first time takes longer. http://www.iaea.org/inisnkm/nkm/aws/htgr/abstracts/abst_iwggcr15.html IWGGCR-15: Technology of steam generators for gas-cooled reactors.
Note: In the past, some high temperature gas-cooled reactors have used multiple small boilers arranged in a ring around the reactor vessel. This produces a very large surface area for the volume that contains the heat exchanging surfaces. I don't know what current thinking is on this design detail but, since the amount of heat is large and supercritical water, rather than steam is involved, I'm inclined to think that as there are efficiency constraints (there's a lot of heat to be lost and we want it to run as cool as possible) rather than size constraints, a large single unit might be the appropriate design starting place for both ends of the hot water loop.
(Photograph of the interior of a pebble bed reactor silo from a January, 2002, Scientific American magazine article by J. A. Lake, et al.) Not unlike a huge charcoal grille with air blowing down through it. Aerodynamically, pebbles behave somewhat like a sintered metal air filter and have acceptably low drag.
REACTOR CONTAINMENT: For a power plant conversion, pebble bed reactors should be installed in individual underground silos instead of above ground. The moisture in the earth provides a good radiation barrier along with being a good heat sink, something pebble beds need. PBMR pebble bed reactors are 8 foot in diameter tubes, about 30 feet tall, made of thick, radiation-proof sheet metal, capable of running at very high temperatures like a boiler, are hermetically sealed in very heavily reinforced underground concrete silos. Since nothing in direct contact with radioactive materials is under pressure, the traditional concrete and steel steam explosion containment vessels needed by conventional reactors are unnecessary, thereby providing a huge saving in both cost and construction time.
Pebble beds do not have a fuel cycle as such. Pebbles are circulated through the pebble bed reactor in much the same manner as a fluid. Each pebble is checked individually for how strong it is and is removed and replaced when too "tired". 10 to 15 trips through the reactor over a two to three year time are said to be typical. Additional "Moderating" pebbles containing only graphite are also added to "dilute" the critical mass to fine-tune the reactor's heat output and burnup rate.
Tired pebbles are removed pneumatically and transported to a central storage area where they are kept spaced from each other to keep a critical mass from forming and automatically packaged in thermally insulated, radiation-proof casks for shipment to a recycling plant.
(Left) From MIT's pebble bed reactor web site.
Pneumatic pebble handling system that removes, measures for remaining
energy, and then either returns a useable, removes a spent pebble or removes
fragments of a broken pebble. A broken pebble was a problem in the
1980's-era German THTR-300 pebble bed reactor.
As with conventional fission nuclear fuel, only about 5% of a pebble's atomic energy is actually consumed during a power run, so pebbles will have to be crushed to powder like quarry rocks and recycled for their remaining energy as is done world-wide with conventional nuclear waste.
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The "Coal Yard Nuke" Conversion Pebble Bed Reactor Top
Illustrating the Coal Yard Nuke idea (as applied to TECO's Big Bend power plant), above is an anatomically correct simplified coal burning power station schematic diagram from Wikipedia. This sketch shows how I think PBMR would like to see their reactor used in this sort of application. The reactor is the tank at the extreme right, with helium in it circulating clockwise through a helium-to-water heat exchanger. The red exit water is supercritically hot and would need to be at 3,200 pounds per square inch to remain water at 1,150 °F. As a gas turbine driver, the PBMR puts out 1,652 °F so it should be plenty hot enough to make supercritical water. The gas turbine version of the PBMR takes in helium at 932 °F, (a delta-t of 720 °F), way hotter than an estimated 400 °F (an almost identical delta-t of 750 °F) from the 40 foot tall supercritical water heat exchanger.
Original image: http://en.wikipedia.org/wiki/Fossil_fuel_power_plant GNU Free Documentation License
Note that as a gas turbine driver, the PBMR is pressurized to 1,323 psi. While gas under pressure has greater density and thus heat carrying capacity, this is less important as a heat exchanger driver. A strong circulating blower is needed here. Because of this, a much less expensive reactor vessel could be used instead.
The water then goes to another heat exchanger, a supercritical water-to-superheated steam heat exchanger, (located in the power plant) where it makes both superheated steam (1,000 °F and 2,400 pounds per square inch) for the high pressure stage of the generator turbine where it is either by-passed or expanded through the turbine and then returned to the steam generator to become intermediate pressure steam (1,000 °F, 552 psi) for the intermediate pressure turbine. After leaving the intermediate pressure turbine the steam, now expanded to low pressure, goes immediately into the low pressure turbine and then exits at near atmospheric pressure and just above 212 °F into the condensing tub. There, the low pressure steam will flash condense into boiler feed water so it can be turned into steam again. The condensing tub is kept cool by a loop of cooling water from the cooling tower (extreme left).
Notice the 88 foot tall reactor is underground and that the supercritical water never touches the radioactive pebbles. The helium is not under pressure, just being circulated by a blower, so there is no possibility of the reactor exploding. Supercritical water was first used in the "Benson Boiler" as a way to reduce the catastrophic consequences of steam explosions in power plants during the twenties.
So we have a no-explosion device (the PBMR reactor) driving a reduced explosion hazard device (the supercritical heat exchanger pair) driving a standard power plant steam turbine from a steam generator that has less than the usual steam plant's typical amount of water in the steam state. I think this is as safe as a power plant can ever be made. Converted power plants will be a little safer than when they were when running on coal.
Thermal Efficiency: This design runs 500°F hotter than a conventional nuclear reactor and does not have the stack heat losses of a coal fired power plant. It's got to be more efficient than either a nuclear or fossil fuel power plant. The latest information (12/07) posted on PBMR's web site says: The reactor is designed for 930°F helium in, 1,700°F out, has about 452,000 pebbles that are expected to last 3 years. They are claiming 40% thermal efficiency and their reactor-generator combination is listed at 165 megaWatt electrical by PBMR and 180 mWe by the NRC.
Generation IV reactors hold wonderful promise of compact conversion units for coal power plants. Conventional uranium fuel pellet reactors and pebble bed reactors have been around for some time. You can buy conventional reactors from a surprisingly wide variety of vendors right now. Pebble bed and prism reactors have only a few vendor-wannabes at the moment. They are waiting for acceptance of their differing designs by various government nuclear authorities around the world.
Modern large power plants are huge, serious machines, costing serious amounts of money, putting out serious amounts of electrical energy, and emitting serious amounts of Global Warming CO2, uranium, radon, and other forms of air pollution.
When you look at a fossil fuel power plant, you are looking at the major cause of Global Warming CO2. You are looking at where the problem of Global Warming will be successfully mitigated. Since mankind can never give up the electricity that keeps his mega-cities alive, after every possible energy gizmo has proven itself of no great value in ending the 10 billion tons of CO2 produced by coal burning power plants each year, we will do what we have to do.
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Who is making and selling pebble bed reactors? Top
Excellent descriptions of all small nuclear reactors can be found at http://www.world-nuclear.org/info/inf33.html and http://www.ne.doe.gov/pdfFiles/Cong-Rpt-may01.pdf
The typical maximum thermal energy needed for converting a large coal-fired generating unit to pebble bed nuclear would be about 1,600 megaWatts of heat. This would drive a 550 megaWatt electrical generator. This is larger than any silo type high temperature reactor being proposed today and going in a direction not being advocated by pebble bed reactor companies. I see multiple pebble silo units, perhaps 200 megaWatts thermal in size, running in tandem as the most practical way to use either pebbles or prism/compacts.
Also, these silo type high temperature reactors are all designed to work with gas turbines rather than work with a heat exchanger such as a boiler. A case can be made for producing a larger modified silo, perhaps incorporating some characteristics of the German thorium pebble THTR-300 which was designed to work with a boiler right from the beginning.
I think a variant, perhaps a ruggedized combination of the best features of both commercially available reactors, is possible that would be optimized for Coal Yard Nuke service. Both the PBMR and the GT-MHR reactors are helium instead of nitrogen reactors. They both appear sophisticated and seem intended for silk-glove "Nuclear Quality" environments rather than the more rough and tumble world of fossil fuel power plants.
What keeps going around in my mind is a pebble bed reactor equivalent of the DC-3 airplane. A rugged, economical, 'simple elegance' example of a high-tech machine - a definitive "Coal Yard Nuke." Perhaps made by one of the big boiler companies. The metal working capabilities are an excellent fit. A company that doesn't already have a heavy investment in the nuclear technology of the past, and big enough to acquire or hire the necessary expertise. One that could produce pebble bed reactors and their boilers as a single, highly integrated system, in the spectrum of sizes needed to supply the entire fossil fuel power plant market. A single, perfected pebble handler, used with perhaps 5 different sized superheated steam generators - 50 to 600 mWe.
The Generation IV Lead-Cooled Fast Reactor ( http://en.wikipedia.org/wiki/Lead_cooled_fast_reactor ) which is supposed to be able to run as hot as 800°C (1,500°F) strikes me as a strong candidate but Generation IVs are intended to be future technology. Lead-cooled fast reactors have seen extended practical service in the Russian Navy. From Wikipedia: "LFR reactors OK-550 and BM-40A, capable of producing 155 MW of power, have been applied on soviet Alfa class submarines. They were significantly lighter than typical water-cooled reactors and had an advantage of being capable of quickly switching between maximum power and minimum noise operation modes, but lacked reliability, as solidifying of lead-bismuth solution turned the reactor inoperable."
The commercially available pebble bed reactors coming into service now are being made in what turns out to be excellent "small" and "medium" sizes for our conversion purposes. For our "large" size, we shouldn't overlook what the now-decommissioned German thorium-powered pebble bed reactor, the THTR-300, has to offer. Equipped much as the proposed fossil-fuel power plant conversions, it actually drove the German power grid for about 2 years (423 days at full load) during the late 1980s. Of interest to us is a 500 mWe successor reactor that was also designed. It would exactly match the boiler needs of modern large fossil-fuel power plants such as Big Bend, providing a one-for-one conversion match. http://en.wikipedia.org/wiki/THTR-300
WESTINGHOUSE-ESKOM: It will take 12 of the South African Westinghouse-ESKOM's (U.S. NRC designation) 180 MWe pebble bed high temperature gas cooled reactors to replace those 4 coal-fired monster boilers at Big Bend. Three reactors running in tandem, each with their own boiler for radioactive pebble dust containment, per generator, would provide an additional 100 MWe of extra power per boiler over the old, existing coal boilers. Reminiscent of those old three-engine airplanes.
http://www.pbmr.com/
PBMR Pebble Bed Modular Reactors web site.
http://www.pbmr.com/index.asp?content=8 Status. Stay up to date.
http://www.nei.org/index.asp?catnum=3&catid=707 
Nuclear
Energy Institute web site.
http://www.nrc.gov/reactors/new-licensing/design-cert/pbmr.html NRC.
<---- Left: Drawing of an approximately 88 foot high, 20 feet in diameter, pebble bed reactor vessel by PBMR. In a steam plant conversion such as the Big Bend rapid-conversion, the tubes coming out of the bottom of the underground reactor would be run vertically to a superheated steam-producing heat exchanger (A.K.A. boiler) located above ground. The reactor is basically just a high-temperature-sheet-metal silo. The heat transfer gas (either helium, nitrogen, or carbon dioxide) is circulated around by a blower. The heat transfer gas simply flows between the spherical pebbles in the bed of pebbles, gets hot, flows to the boiler, then is cooled off by the water in the supercritical water heater, then returns to the bed of pebbles to be heated again. Simple eh? That's the whole reactor cooling loop. (Extracted from an image on ESKOM's PBMR web site)
GENERAL ATOMICS: Or, instead, it would take 8 of the competing American made General Atomics GT-MHR (U.S. NRC designation) 325 MWe "Prismatic" high temperature gas cooled reactors. With two running in tandem per superheated steam generator, they would provide an excess of about 200 MWe of extra power per boiler over the old, existing coal boilers. Prismatics use stationary prism-shaped ceramic high-temperature fuel elements. GT-MHRs use both natural Doppler Broadening temperature limiting and control rods for more precise "cruising" heat adjustment and to provide a rapid cold shut-down capability.
Like a pebble bed, its heat is carried to the steam boiler with unpressurized circulating helium so it is incapable of explosion. Also like the pure pebble bed, the HT-MHR has a Level 1 safety designation: "LEVEL 1: No need for active systems in event of subsystem failure. Immune to major structural failure and operator error." (While General Atomics also has pebble expertise, the U.S. seems to be more interested in developing the South African Westinghouse-ESKOM pebble bed reactor at this time.) From G.A. site -->
General Atomics, like Westinghouse, has a foreign affiliate. In their case: "In 1993, General Atomics (GA) and the Russian Federation Ministry for Atomic Energy (MINATOM) initiated a joint cooperative program to develop the Gas Turbine - Modular Helium Reactor (GT-MHR). In 1994, the primary emphasis of the program was refocused on development of the GT-MHR for disposition of surplus Russian weapons-grade plutonium. In 1996 and 1997, Framatome and Fuji Electric, respectively, also became partners in this program. The scope of the program includes construction of a GT-MHR plant at Seversk (formerly Tomsk-7) to destroy a portion of the Russian inventory of surplus plutonium and to produce electricity for the surrounding region." - From the General Atomics GT-MHR web site.
http://gt-mhr.ga.com/ General Atomics' GT-MHR web site. http://www.ga.com/index.php General Atomics company web site http://www.nei.org/doc.asp?catnum=3&catid=711 Nuclear Energy Institute web site.
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Cost Estimates Based Upon Crude Numbers: Top
Reactor Cost:
Putting it into perspective by first thinking about airplanes: We're talking about a nuclear reactor that will be built in the thousands, like an airplane. The latest and greatest American passenger jet is the Boeing 787 Dreamliner. With almost 200 orders at over $150 million each pending, it hasn't even flown and already it is a 30 billion dollar financial success. Check it out: http://en.wikipedia.org/wiki/Boeing_787
Converting to nuclear to avoid the CO2 (carbon) tax: TECO is the Tampa Electric Company. Their 'Big Bend' facility is a large coal-fired power plant with three 445 mWe boilers and one 486 mWe boiler for a total of 1,821 megaWatts of power. A carbon tax of $40 per ton of CO2 produced, intended to reduce CO2 emissions into the atmosphere and thus reduce Global Warming, is being talked about in Washington these days. Coal makes a lot of CO2. If TECO continues to burn a lot of coal and make a lot of CO2, TECO is going to have to pay a lot of carbon taxes and then pass that cost on to its less than delighted electric customers. Also, producing electricity without making CO2, like 'renewables' do, attracts government subsidies like a magnet. Carbon Tax: http://en.wikipedia.org/wiki/Carbon_tax EcoTax: http://en.wikipedia.org/wiki/Ecotax Carbon Tax vs. Cap-and-Trade: http://www.carbontax.org/issues/carbon-taxes-vs-cap-and-trade/
Finding Big Bend's annual CO2 output by the 'CO2 per kilo-Watt-hour' method; Big Bend's maximum generation capacity is 1,821 megaWatts, or 1.821*109 W, times 24 hours/day = 44*109 W hours / day, * 365 days / year = 16*1012 W hours / yr, or, converting to kiloWatts, 16*109 kiloWatt hours / yr.
Calculating the CO2: 16*109 kWh / yr * 2.0 lbs of CO2 / kWh = 32*109 lbs or 16*106 tons CO2 / yr. That's 16 MILLION tons of CO2 a year, or 44,000 tons of 'Greenhouse Gas' CO2 a day, folks. (coal's CO2, http://tonto.eia.doe.gov/FTPROOT/environment/co2emiss00.pdf table 4 )
Carbon Tax at $40 per ton of CO2, Big Bend's annual CO2 tax: 16 million tons of CO2 / year * $40 per ton CO2 tax = $640 million per year CO2 tax.
Incidentally, according to my TECO bill, Big Bend's electricity retails at about $0.10 per kWh. So, 16*109 kWh / yr * $0.10 / kWh = $1.6*109 or 1.6 billion dollars per year from Big Bend. That $40-a-ton carbon tax is going to boost your TECO bill by about 30% if they don't convert to nuclear.
A single facility containing four 500 mWe size reactor-boilers patterned after the THTR-500 might be built for $800 million. The reactors would be about 15 feet in diameter by 25 feet high sheet metal silos in a 50 feet in diameter by 40 foot deep underground concrete silo. The boilers, with a house-size footprint, would be above ground, extending about 50 feet above grade. How much would a mass-produced 500 mWe reactor-boiler unit cost these days? How much to build the facility, install the reactor-boiler units, and then connect to the adjacent fossil fuel power plant? How about its pebble handling machine?
Thinking of pebbles as if they were only charcoal briquettes, and ignoring their nuclear aspects, and considering that the burner-boiler part of a 500 mWe fossil fuel power plant generating unit has a direct field (installed) cost of about $200 per kW these days (out of the $1,000 per kW total installed cost of a fossil fuel power plant - Black and Veatch), we get a rough cost of about 100 million dollars for a basic pebble reactor-boiler module. Typical fossil fuel power plant items covered in that $200 per kW fossil fuel plant cost are everything necessary to deliver steam to the generator turbine: the boiler, coal handling equipment, coal pulverizer, both forced and induced draft fans, fly ash precipitators, water treatment, condenser, heat recuperator, and one-half the cost of the stack.
Doubling that 100 million to cover everything else besides the reactor-boiler unit would give us a rough cost of around 200 million dollars per 500 mWe reactor-boiler unit figure. Big Bend needs four such units, so that would run the price tag to 800 million dollars. Not having to pick up the tab for TECO's carbon tax is a good deal for TECO's customers, TECO is sure to make money on the deal somehow with that much money flowing through their hands, and a fossil fuel plant converted to a full-power, zero-emissions power plant would be a wonderful environmental gift not just to Florida, but to the entire world.
A second opinion, using 3 smaller reactors per 500 mWe generator turbine: Using MIT's complete pebble bed power plant analysis as a template, and removing all non-boiler items since we are upgrading an existing, running power plant, my order-of-magnitude guess for Big Bend's upgrading project would be about $40 million per pebble bed reactor, or, about a half-billion dollars for the entire conversion project. Since this is the first project, we're talking hand-made, not mass-produced reactors. PBMR's 20 feet in diameter, 88 feet long reactors have been designed from the start to be mass-produced in substantial quantities like airplanes and to be sold at low per-unit cost. PBMR's company name stands for: Pebble Bed MODULAR REACTORS - a large, but readily shippable load for both ships and sea-going barges along with many river barges. A pebble bed reactor would occupy a 24 x 90 foot double-long, triple wide "High-Cube" shipping container dimension on container ships and over land would be limited to select route trains and trucks.
Made of heavy, high-temperature sheet metal like a boiler, a pebble bed reactor silo is simple when compared with a typical conventional nuclear reactor. No huge castings or forgings. It does have a one meter thick graphite cylinder around it's 20 foot outer circumference. http://en.wikipedia.org/wiki/Nuclear_graphite http://en.wikipedia.org/wiki/Graphite
Since there is nothing under pressure in the radioactive portion of the reactor, it is incapable of exploding so doesn't need to be very strong. As seen in the drawing #8, above, the reactor silo is installed in a thick underground silo designed to transfer "Doppler Broadening hot idle" heat to the surrounding ground while also insuring that no radioactive material can escape. Pneumatic tubes are used to carry pebbles, inert dilution spheres, and moderator spheres to and from the silo to monitor the state of the pebbles. It is estimated a pebble will make 10 to15 trips through the reactor over a three year period of time before being removed from use.
Fuel Cost:
Here are some numbers for thought - according to figures published by the Nuclear Energy Institute the average cost of generation (in US dollar cents per kilowatt-hour) from various sources in 2006 was as follows: Petroleum - 9.63, Gas - 6.75, Coal - 2.37, Nuclear - 1.72.
Conventional fuel rod nuclear electricity costs about $16 per MegaWatt-hour to make (Rod Adams, Atomic Show # 53, citing industry figures) and electricity generally sells for about $100 per MegaWatt-hour. Big Bend is a 1,800 Mega-Watt Electrical plant and there are 8,760 hours in a year, so we're talking about 1.6 billion dollars a year gross income here. One pebble makes 0.33 kilowatts of electricity per year and costs $10 (Kemm). So, [1,800,000 kWe/yr / 0.33 kWe/yr per pebble = 5,450,000 pebbles * $10 per pebble = $54.5 million annual pebble bill] 1.6 billion dollars income from perhaps 55 million dollars worth of pebble heat a year isn't bad. A person should be able to make a decent living doing pebble-power on an old, amortized power plant even after making the mortgage payments on their new Coal Yard Nukes..
Comparing pebbles and coal. The reactor, rated at 165 mWe, divided by 0.4 thermal-to-electrical efficiency comes to 412 megaWatts thermal input. For 3 years worth of hours = 412x106 W t x (24h x 365d x 3y) hours = 10,800x109 Wh thermal. 10.8x1012 Wht x 3.41 BTU per Watt-hour is 36.8x1012 BTU. According to the EIA, (Oct 2007) delivered coal was $1.52 per million BTU in the U.S.A. $1.52 per 106 BTU x 36.8x1012 BTU = $56 million for the equivalent BTU heat in U.S. coal. That means that $56x106 divided by 0.452x106 pebbles = $124 per pebble.
Or, a single pebble might be worth $124 of coal. At the present time, PBMR's pilot pebble plant is supposed to make 270,000 pebbles per year, or a little more than enough to keep one PBMR reactor well-fed. A PBMR reactor takes about 450,000 pebbles. Thought you'd like to know the whole story.
(Einstein's first wife always checked his arithmetic. I sure ain't no Einstein. You better check both my thinking and my arithmetic.)
At 80,000 MegaWattE-days per ton of uranium, Big Bend should go through about 8 tons of uranium a year. (Your car weighs about 2 tons). 8 tons * 2,000 pounds per ton = 16,000 pounds * $100 per pound of uranium yellowcake (today's street price) = $1.6 million for the basic uranium ore. The other $52.9 million in pebble cost goes to the pebble people for enriching the 0.7% radioactive U-235 Uranium ore to about 8% Uranium-235 and making it into pebbles. In real life, enrichment will cause them to go through maybe $20 million worth of ore with the depleted, non-radioactive U-238 being stockpiled for sale later when we get a fleet of breeder reactors so we can make the non-radioactive U-238 into radioactive Plutonium-239 and then burn that up as "Energy Metal". Pebble production is a process not unlike a gosh-awful high-tech brick factory. Now you understand why PBMR is building a pilot pebble plant.
Non-radioactive Thorium-232 can also be bred into radioactive Uranium-233. Since, with breeding, there is more Uranium-238 available than mankind will ever conceivably use, and there is three times as much Thorium-232 as Uranium-238, I don't understand critics of nuclear electricity saying that we will run out of Uranium in a couple hundred years. Just remember: Radioactive Uranium-235 is like matches and non-radioactive, but breedable, Uranium-238 and Thorium-232 are like firewood. Don't let them trick us by talking us into burning up all our matches by forbidding breeder reactors.
CONVENTIONAL POWER PLANT COAL COST: Compare that with the 6,400,000 tons of coal Big Bend is burning up every year (from "Big Bend" section, above). At today's street price of about $35 per ton, that comes to $224 million for coal. (I'll bet that's why TECO bought their own coal mine). Using pebble beds to supply the refinery processing heat for those 25 synthetic gasoline-from-coal refineries we don't ever seem to be getting around to build, that much coal might make over 40 million barrels of Fischer - Tropsch synthetic crude oil ($2.6 BILLION at $65 per barrel - go figure why the coal companies are selling so cheap) or about 2 days supply for the entire United States! Climate Change is crazy costly in every way!
"CLEAN COAL" COMPARISON: For a "Clean Coal" CO2 cost comparison, here's an announcement of a real-life Carbon-Capture and Sequestration Project: "Powerfuel (UK) Signs License with Shell for 900 MW Power Plant - U.K.-based coal producer and power generator Powerfuel PLC, which is 30% owned by Russian coal miner Kuzbassrazrezugol, has signed an agreement with Royal Dutch Shell PLC to use Shell's patented technology to build a near-zero carbon emissions coal-fired power station. The project is expected to cost about GBP1.1 billion to GBP1.2 billion (US$2.2 to US$2.4 billion) to build. Construction will take three to four years and may involve building a pipeline (not budgeted) to transport carbon dioxide to storage sites in the North Sea." (Much more costly, but this does get you a complete brand new power plant that's going to burn coal inefficiently for at least the next 50 years).
From the Shell press release: "The UK unit of oil giant Shell has signed a license agreement with Powerfuel that entitles the company to use Shell’s proprietary gasification technology in its proposed 900MW integrated gasification combined cycle coal-fired power station in Hatfield, South Yorkshire. April 21, 2007" - And this plant is only about 1/2 as powerful in MegaWatts as Big Bend.
The big upside of using nuclear heat wherever possible in huge industrial plants like Big Bend is that our children and grandchildren won't have to starve and freeze in the dark forever just to keep Global Warming at bay. They can continue to make vehicle fuels, traffic jams, plastics, fertilizers, etc., for longer than 600 more years out of the coal and other fossil fuels we don't have to burn just to make electricity and air pollution.
http://www.world-nuclear.org/sym/1999/kemm.htm Kelvin Kemm's comprehensive 1999 description of the details and costs of the South African Pebble Bed.
http://web.mit.edu/pebble-bed/Economics.pdf 1998 MIT (Andrew Kadak) economic analysis of pebble bed reactor construction costs. (ESKOM had a lower estimate for their Koeberg pebble bed powered power plant in South Africa).
http://nuclear.inl.gov/deliverables/docs/ngnp-methods-dev-programc-04-02293.pdf 2004 U.S. in-depth summary of all known Doppler-Broadening reactors.
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How the reactors would be installed and connected: Top
A Google Earth® photo of TECO's Big Bend power plant in Tampa Bay shows that the dark coal yard area is large enough to build a big shopping mall - ample room for twelve 50-foot-in-diameter 180 MWe PBMR pebble bed reactor silos. Perhaps in a circle 250 feet in diameter for the silo centerlines. They could be arranged in 4 groups of three reactors each with each reactor having its own boiler radiating outward from the outer edge of the reactor silo ring like spokes on a wheel.
The ring should be sized for 2 extra reactor
silos to allow for an access road to the reactor control/support building
located in its center. The access opening would be facing away from
the power plant to allow an open interconnect area on the other side for the
steam and feedwater piping. The extreme outer edges
of the boilers might form a ring 400 feet in diameter or, at most, the length of the
ocean-going coal barge tied up at the bay end
of the coal yard. A linear layout might be about 700 feet by 300 feet. 
PBMRs at Big Bend are a worst-case situation, using the lowest-power pebble bed available to power a very high power coal-burning generating plant. At the other end of the spectrum, the entire J. R. Whiting plant in Michigan, three 100 MWe boilers, could be powered by a single General Atomics 325 MWe GT-MHR pebble bed reactor.
For scale, notice the diameter of the smoke stack bases - they're also about 50 feet in diameter. In winter, manatees hang out in the warm water that's being discharged just below the stack plumes.
I think the Hillsborough county desalination plant is in the upper right corner. It produces 25% of the county's drinking water. It is no coincidence the desalination plant is located next to a power plant. Desalination for mega-cities and mega-suburbs like the Tampa Metro area requires massive amounts of energy regardless of which method is used.
Multiple pebble bed reactor installations can be a circle of underground silos - one reactor per silo, somewhat like a missile silo complex - around an above ground central control building having an underground pebble monitoring and replacement facility as its basement.
Cooling water in the form of a lake or river is almost
always present at power plant sites. This means ground water is usually present
only a few feet below ground level. This is a plus when it comes to buried
pebble beds since the moisture in the ground acts both as an additional
radiation shield and also would carry away any 'afterheat' that would be present
in the reactor in the event of an abrupt loss of coolant or coolant circulation.
All underground facilities constructed below water levels have to be water tight
and some means for sump drainage provided. A well known example of this
type of construction are the
subways of New York City. Being within a few feet of sea level, anything
underground at Big Bend will need that type of construction. In addition,
despite the
fact the silos are hermetically sealed to keep radioactive materials contained,
a mesa-like mound, perhaps 30 feet high, should be provided for the entire
reactor facility to guarantee it will never be immersed in water during a storm surge from
a hurricane.
For a steam power plant conversion installation, the pebble-heated supercritical water from the underground reactors would heat the new conversion superheated steam generator located in the power plant building. See the 6 unit Ludington, Michigan, (Consumers Energy) pumped water energy storage site photo (at right - Visit ) for an example of how this type of equipment can be arranged. Note the tall overhead equipment crane (right) that runs on tracks. Easy way to remove and replace entire pebble bed reactors.
The supercritical water heated steam generator's output lines would be run to the existing coal boiler steam discharge pipes, through a new isolating valve, and then via the original steam lines to the electricity generating turbine set.
Having valved feedwater and steam lines, along with not removing the plant's coal boilers and their coal handling/pulverizer/precipitator systems, is quickest, shortest shut-down, least costly, and gives the plant a "Flex-Fuel" capability.
Of course, we should convert only one of the four coal-fired boilers first to make certain everything works as planned and to fine-tune the design's details for the remaining three units.
Adding pebble bed reactors has no effect whatsoever on the water used by a power plant. In the case of Big Bend's manatees, this is a very good thing.
Long superheated steam lines are unusual for a power plant but not for an oil refinery complex.
Per coal boiler, we would have one supercritical water pipeline connecting its reactor set and the new steam generator. There is no reason all 12 supercritical water heaters could not be connected in parallel for operational flexibility. And Big Bend's four coal-burning boilers are silent, their smoke stacks cold. Simple, eh?
Now the cat's out of the bag.
There are many ways to convert a power plant. Every power plant in the world is somewhat different from all the others. These are just general overview thoughts that come to mind without knowing the intimate details of this particular plant, how it's being operated or what its owner's future plans for it are.
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A small one-reactor demonstration project. Top
From Coal-Burning to Zero Emissions: A Proposed Conversion Demonstration Project.
This
is an excellent place
to establish a zero-emissions "Coal Yard Nuke" demonstration plant: Michigan's Consumers Energy's "J.
R. Whiting" power plant located north of Toledo on the western tip of Lake Erie near Erie, Michigan (Right).
This extremely well maintained 50+ year-old plant has three 102 MWe to 124 MWe superheated steam boilers. According to CARMA, it emits 2,780,000 tons of CO2 each year.
Any of it's three generating units could be easily driven by a single 180 MWe PBMR pebble bed or all of three by a single 325 MWe GT-MHR prismatic reactor. The 875 acre site would also provide plenty of room for a new visitor's center. http://www.consumersenergy.com/content/hiermenugrid.aspx?id=21
Consumers' environmental web page: http://www.consumersenergy.com/welcome.htm?/content/hiermenugrid.aspx?id=130
Consumers Energy has a long and successful track record with nuclear power plants. They took the 1962 "Big Rock Point" nuclear power plant all the way through its life cycle and eventually decommissioned it to an empty green field. Only the temporary spent fuel storage remains. The Big Rock Point decommissioning story (1.5meg PDF file). http://www.consumersenergy.com/uploadedFiles/Environment/BRP_Journey_s End final.pdf
A project engineer for over 30 years, I'm certain many unanticipated issues will emerge during the design, fabrication, installation and operation of the world's first "Coal Yard Nuke." This site is located just south of the Fermi II power reactor facility near Monroe, Michigan. What better place to have a demonstration facility than near an existing nuclear plant and within several hundred miles of several of the country's leading schools of nuclear engineering, several of the nation's leading nuclear reactor laboratories, and the massive fabrication shop resources to be found in the Detroit area?
Many of the coal-burning power plants that are excellent candidates for nuclear conversion are small and almost forgotten, but usually very well-maintained, plants that are over 50 years old and could easily run another 50. This rejuvenation of the worlds oldest and dirtiest coal power plants also makes a darn good long-term investment in the world's energy future as well as eliminating the world's major source of carbon dioxide. Boilers heated by oxidizing direct flame burn out much sooner than boilers heated by inert pebble bed reactor gasses. The retail value of the electricity made by one of these old plants is often well over a half billion dollars a year.
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Project Merlin:* A 3 to 5 Year Plan
"We've done it before and we can do it again."
*Suggested initial planning phase codename.
Initially, there should be a conference of all the world's high temperature, gas-cooled reactor experts followed by a conference of potentially impacted power producers. Identification of potential project participants.
This plan picks up at the point where the decision has been made to convert existing coal burning power plants to Coal Yard Nukes and to build additional power plants using the "Hybrid" idea.
The world clearly has sufficient mineral, industrial, and construction resources to make, install, and fuel at least 500 PBMR reactors every year.
IMPLEMENTATION STRATEGY: To make enough reactors quickly enough, PBMR would have to license their reactor to be built simultaneously in as many as 8 different countries. This system worked well during during World War II where, for example, excellent British designs were built in huge volume in American plants. Times have changed and globalization of heavy industry has made this an even better idea.
Example: The impressive British Rolls-Royce "Merlin" aircraft engine was also built by the Packard Motor Company in the United States. With the greater availability of the Merlin engine, the American P-51 Mustang, a remarkable airframe but hampered by it's General Motors-built Allison V-1710 engine, was re-engined with the Merlin engine to produce what many consider the best overall piston-engine fighter airplane ever built. And, in just several years, the Americans built more than a total of 15,000 Mustangs in several different factories around the United States.
Overall, 168,000 Merlin engines were built in 5 different factories with the most, over 55,000, coming from Packard. 4 Merlin engines powered the huge British "Lancaster" heavy bomber, 2 powered the amazing British "Mosquito," and, of course, it was the engine used from the very start in both of the also-famous British single-engined "Spitfire" and "Hurricane" fighters.
The Merlin name came from the bird (a small falcon) rather than King Arthur's legendary magician.
As it was in the decade before World War II, the world is again in a period of disbelief as we watch and ponder the slowly gathering storm of climate change.
I see the PBMR reactor as the "Merlin engine" that will provide the CO2-free power we absolutely must have to win the war on Global Warming.
Construction Project Schedule: (An Outline Under Construction itself)
Safety trumps everything else.
In times of dire emergency, time is no longer on your side. You have to "Go with what you got." Job 1: Accept the PBMR reactor and PBMR pebble as the only standard high-temperature conversion reactor for the first 1,000 installed units. Accept that whatever it is, it is "good enough" for emergency CO2 mitigation work.
First Conversions: Under IPCC authority and using South African-built reactors from inventory, build 8 demonstration conversion facilities (on existing old 50 to 100 mWe generating units) in the United States, Germany, United Kingdom, China, Japan, India, Russia and Brazil so local engineers and contractors can see the Coal Yard Nuke power plant modification in the context of their local equipment and construction methods. This will also give them insight on how they can build additional new very low cost 'Hybrid' nuclear power plants out of locally available equipment using local construction methods.
Concurrent with "First Conversions," Main body of world-wide conversion work:
First 180 Days: Secure 8 different reactor builders in the 8 different countries. They would have overall responsibility for their products and to subcontract heat exchangers designed to the specific needs of customers using their reactors. Since several billion pebbles will be needed every year, as many as 20 different countries will need to build pebble manufacturing facilities.
Second 180 Days: Build tooling and production facilities for building reactors, heat exchangers, and pebbles. Begin engineering on specific conversion projects.
Third 180 Days: Build initial reactors, heat exchangers, and pebbles. Break ground on at least 16 full-size pilot conversion projects in the 8 different "home" countries.
Fourth 180 Days: Install and test equipment at 16 full-size pilot conversions projects. Energize.
Fifth 180 Days: tbd
Sixth 180 Days: tbd
Seventh 180 Days: tbd
Eighth 180 Days: tbd
Ninth 180 Days: tbd
Tenth 180 Days: tbd
Taking advantage of the lessons learned in the computer world. Top
Standardized devices does not mean identical devices. Like railroad cars, they only need to be identical where they connect. Leaving the space in between "malleable" provides space for improvements in safety, cost, performance, capacity, or anything else that may be deemed now or later to be desirable. Freedom like this always ignites furious competition among us technical geeks. It always turns out that super-standardization is super-stupid in the long run.
What does this mean for us? Standardize external dimensions - where things touch and connect to other things. The external size of pebbles. Where the pebble bed reactor connects to its steam generator (for a hybrid power plant) or supercritical water heater (for a Coal Yard Nuke). These are some of the important interfacing points.
The steam generator sizes, temperatures, and turbine steam line connections will have to accommodate whatever temperature, layout, and line sizes the original plant presents. This would be something like your home getting a new furnace. Always some "file and fit" work needed here.
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Mass producing pebble bed reactors for the world's power plants.
Any country that can make a superheated steam boiler that will last several years before burning out can make acceptable pebble bed reactors.
Production lines provide substantial quality and cost benefits. That's good because over 25,000 will be needed.
Conventional nuclear reactors require some of the world's largest castings and forgings. Only a few countries can make them. It's questionable if the United States has the industrial might to do this kind of very heavy work anymore. China, Japan, Korea, Russia, perhaps Holland and Germany come to mind.
Pebble nuclear could be considered 'light'
nuclear.
(Right) Example of a highly government-regulated, physically large, multi-million dollar product being made at the rate of one a day.
Almost as simple as a farm silo and of modular design to facilitate mass production, Pebble bed reactors are 20 feet in diameter tubes, about 90 feet tall, are made of thick, radiation-proof, high temperature sheet metal, capable of running at very high temperatures like a boiler, are installed in hermetically sealed, very heavily steel bar reinforced underground concrete silos.
Some of the wind is at our backs. Since these reactors are limited-life and built as a stop-gap solution to an emergency, we can sacrifice a lot of thermal efficiency for simplicity and reliability. A really good precedent for a generic Coal Yard Nuke reactor was the World War II liberty ship. http://en.wikipedia.org/wiki/Liberty_ship Read the story, it's inspiring and reminds us of a day when the citizens of the United States were not afraid of their own government and the government wasn't afraid of it's citizens.
There is no steam in the reactor to explode so the traditional concrete and steel steam explosion containment vessels needed by conventional reactors are unnecessary, with reinforced concrete silos with bolted tops being used for reactor containment instead, thereby providing a huge saving in both cost and construction time.
The competition arising from simultaneous mass production of standardized pebble bed reactors in as many as 8 different countries will bring about an amazing drop in both the reactor's fabrication complexity and cost while creating "build quality" competition. Japan, South Korea, Taiwan, India, Brazil, Holland, Russia, South Africa, or China are possible early manufacturers.
Countries with High Temperature Gas Reactor programs (Doppler Broadening reactors) include China (Pebble Bed), Japan (Prismatic), South Africa (Pebble Bed), Russia (Prismatic), Netherlands (Pebble Bed), Germany (Pebble Bed, inactive), U.S. MIT (Pebble Bed) & General Atomics (Prismatic), Great Britain (Magnox, old), North Korea (Magnox), India (Thorium CHTR).
http://www.indian-nuclear-society.org.in/conf/2005/pdf_3/topic_03/T3_CP3_Dulera_Paper1.pdf Indian Compact High Temperature Reactor Paper
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Mass producing pebbles and prisms. Top
TRISO Pebbles are being produced at the present time ONLY at a pilot plant near Pelindaba, South Africa. At one time it was suggested that four full pebble plants be built in various parts of South Africa to assure the world a steady supply of pebbles. The pebbles South Africans are currently making were actually developed by the Germans for a reactor they shut down about 20 years ago. The German pebble is considered the best spherical design. South Africa, rich in uranium, have licensed the pebble and its manufacturing technology from the Germans.
Also, not to forget the pebble's sibling, the General Atomics prism-shaped Doppler-Broadening fuel element. General Atomics is partnering with Russians in the manufacture of prisms so that means a second path to self-controlled nuclear fuel exists and we may have technology, quality, and cost choices. General Atomics and Babcock and Wilcox are U.S. companies with TRISO Pebble manufacturing experience in the distant past.
The United States produced the very first pebbles, and many others are thought to have produced at least small quantities of Doppler Broadening fuel elements for laboratory investigation. The technology is not extremely high, is largely ceramic, and has been around for a long time. However, like conventional nuclear fuel rod manufacture, a pebble's radioactivity demands isolation from human operators so automated production with extremely consistent quality is where the high technology aspect will come into play.
To meet the pebble/prism demands of a three-year emergency program for the "Coal Yard Nuking" conversion of all the world's coal-burning power plants, pebble/prism manufacturing plants will have to be set up in many of the 20 uranium or thorium-rich countries currently mining, processing and selling uranium or thorium ore on the world market at the same time as the mass production of the reactor-boiler modules is begun in perhaps 8 different countries. Eventually, there would be a big enough stockpile of all kinds of spent fuel pebbles to justify adding recycling facilities to the pebble plants.
TRISO Pebbles are a very versatile fuel form and, in addition to the "classic" Uranium, both pebbles and prisms could take advantage of MOX and Thorium blends, along with various long burn breeding blends, some of which would be designed to produce as high as several hundred thousand mega-watt days (mWd) per ton output, as compared with the typical 40 to 80 thousand mWd delivered by our generation II reactors. There's a great deal of variety out there to fuel a very competitive new energy market.
Since nuclear fuel pebbles/prisms are small, many different uranium and thorium producing countries could be competing fuel vendors because the transportation costs of nuclear fuel, one three-millionth as heavy for the same energy as coal, would be negligible. One ton of uranium currently provides almost 100 thousand MegaWatt-Days of electricity per 1/15 recycling in a 33% efficient conventional reactor and an average freighter can carry 30 to 40 thousand tons. http://en.wikipedia.org/wiki/Cargo_ship
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Mass producing the pebble bed reactor builders and operators. Top
(Below) The HTR-10 Pebble Bed Building at
Video about
China's pebble bed reactor produced by Australians. Click "Windows
Media" when you get there.
We could have converted all our coal-burning power plants to pebble beds in the same time as we've been in Iraq. The war in Iraq has dragged on longer than United States' participation in World War II. During the time WWII took, the United States alone built 3,200,000 (that's three million, two hundred thousand, folks!) military vehicles - from Jeeps to tanks to 80 aircraft carriers and thousands of support vessels along with training over 5 million fighting men. That's a hell of a lot of steel and muscle. Realize also the Russians, Brits, Japanese and Germans combined more than matched us. Don't ever try to tell anyone who knows a little WWII history that the entire world combined can't build, make pebbles, and train operators, for perhaps 20,000 pebble bed reactors worldwide in the same time period. Don't forget we did the entire Manhattan Project in less than 5 years. http://en.wikipedia.org/wiki/Manhattan_Project
Today, most reactor operators are trained like airplane pilots on reactor-simulating computers that duplicate the actual reactor control room computers. There are perhaps six things a conventional PWR reactor operator needs to keep in mind when operating a reactor in "cruise" mode. I haven't the foggiest notion of what, if anything, is needed to "cruise" a pebble bed. Simulators have proven to be an effective way to train airplane pilots since before WWII. Almost every country has at least a national airline, so almost every country knows how to make this type of training happen quickly.
For example: http://www.microsimtech.com/ PC-based Advanced Boiling Water Reactor (and others) Nuclear Power Plant Simulator for Microsoft Windows XP. You can download a demo from this web site and take a test drive of your favorite type of reactor. Available: PCTRAN Personal Computer Transient Analyzer - ABWR Advanced Boiling Water Reactor - ARS Advanced Reactor Simulators - SFP Spent Fuel Pool Accident Simulator - AP1000 Westinghouse AP1000 PWR (Pressurized Water Reactor) - Areva EPR Generation III-Plus PWR EPR - TRIGA Experimental Pool Reactor Simulator
Also:
http://www.ae4rv.com/store/nuke_pc.htm Nuclear Power Plant Simulator for Windows PCs - Vista compatible, Pocket PC version available. $9.95, Download Free Demo.
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"E" Bonds to Pay For Coal Yard Nukes? Top
To pay for the power plant conversions, we could be urged again to buy "E" Bonds - this time the "E" would stand for Environment. http://en.wikipedia.org/wiki/War_bond
Paying For Pebbles: California's "Partial
Zero Emissions Vehicle" standard offers the world a clean vehicle standard
that is very valuable. (1)
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Three other ways we can eliminate substantial amounts of CO2: Top
Our buildings: Half the energy used by the average building is for heating or cooling. Where fossil fuels are now being used, convert residential, commercial, and industrial heating to electrical heating to further reduce CO2 emissions from (typically high-sulfur) heating oil, gas and coal. Residential gas or oil furnaces would need to have their burner module replaced with an inexpensive electrical module, much like we did when we converted from residential coal to gas or oil right after WWII. Residential electric heat, heat pumps, and air conditioning are electrical already so no change would be needed there.
Our vehicles: Using only nuclear heat, produce only synthetic CO2-neutral gasoline, diesel, and jet fuel made by using the "Air + Water + Energy = Oil" technology. Our 3-way catalytic converter equipped cars are good to go as they are by just using the new gasoline*.
Our ships: The
world's 30,000 large ocean-going ships burn about 5 million barrels of oil every
day - 1/4 of U.S. daily consumption. An ocean-going ship has about a 30-year life.
We would burn only
synthetic CO2-neutral diesel in existing ships and equip all new ships with only
nuclear engines.
http://www.guardian.co.uk/frontpage/story/0,,2025725,00.html CO2
output from shipping is twice as much as airlines · Maritime emissions not
covered by Kyoto accord · Studies suggest 75% rise in 15 years as trade grows
* All countries would have to build their automobiles to California's current "Partial-Zero Emission" standards to take full advantage of CO2-neutral gasoline. Partial-Zero Emission cars are already available. Most U.S. and foreign manufacturers have several models of this automobile type in their product line already for selling in California. I drove a "Partial-Zero Emission" Camry in California's coastal mountains for a week - ran great, very good mileage.
It's possible. France closed its last coal mine in April, 2004.
(End of article on converting existing power plants from coal to nuclear. Technical sections follow.)
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----------- Technically Speaking Sections -----------
The Hard Truth about Energy. Top
The Energy market is a market where value is expressed in units of HEAT. So, thermal is what it's all about.
A fact or "Law" of thermodynamics: You cannot get all the ENERGY OUT IN WORK that you put in IN HEAT.
Success is defined by: (1) how much you get out for how much you put in and (2) how little damage the process does to the environment.
In the case of automobile engines