coal2nuclear.com 
coal2nuclear.com
The Newer Nuclear Reactors
A very high quality source of information about small nuclear reactors: http://www.world-nuclear.org/info/inf33.html
Your neighborhood nuclear reactor is a monstrously large descendant of the small original 1955 model reactor developed to power the world's first nuclear submarine, the Nautilus and can't replace coal.
Only reactors that are possible candidates for replacing coal appear on this web site.
Nuclear reactors are just a different kind of fire. Instead of combusting hydrocarbons to release energy captured from sunlight as fire does, nuclear reactors release energy by splitting the atoms in the energy metals uranium, thorium, and plutonium. Reactor radiation travels at most only several feet. Nuclear fuel is three million times as powerful as fossil fuel, is available in unlimited quantities, and it doesn't add fossil fuel's Global Warming Jurassic Age carbon to our atmosphere. Plenty of good reasons to switch to nuclear heat wherever possible. Just like there are many different kinds of heat engines, there are many different kinds of nuclear reactors - some very large, others very small - all of them extremely powerful for their size and with incredible fuel endurance - some run 30 years without refueling.
Nuclear reactors as simple as a mud puddle are known to have occurred naturally. Example: OKLO, Africa.
The world's oldest known nuclear reactors operated at what is now Oklo in Gabon, West Africa. About 2 billion years ago, at least 17 natural nuclear reactors achieved criticality in a rich deposit of uranium ore. Each operated at about 20 kW thermal. At that time the concentration of U-235 in all natural uranium was 3.7 percent instead of 0.7 percent as at present. (U-235 decays much faster than U-238, whose half-life is about the same as the age of the Earth.) These natural chain reactions, started spontaneously by the presence of water acting as a moderator, continued for about 2 million years before finally dying away.
During this long reaction period about 5.4 tonnes of fission products as well as 1.5 tonnes of plutonium together with other transuranic elements were generated in the orebody. The initial radioactive products have long since decayed into stable elements but close study of the amount and location of these has shown that there was little movement of radioactive wastes during and after the nuclear reactions. Plutonium and the other transuranics remained immobile.
Sources: Wilson, P.D., 1996, The Nuclear Fuel Cycle, OUP.
© World Nuclear Association. All rights reserved 'Promoting the peaceful worldwide use of nuclear power as a sustainable energy resource'
Contact WNA
Monster Nukes, Mininukes, Micronukes
Like fire, nuclear reactions are a process that can occur naturally but, like the modern uses of fire, man usually sets thing up in such a way as to optimize the use of the resulting heat while minimizing the chances of the fire getting out of control and destroying people and property. 'Fireplace' says it all.
Reactors vary in size from the monsters being built in other countries right now to reactors as small as the propane tank on your back yard barbeque.
The 34,000 horsepower TRIGA-like Hyperion™ reactor (left) is the author's idea of a MicroNuke, a reactor as powerful as 25 of the world's largest wind turbines.
Horsepower Race
The bar graphic at right gives us some idea of the power league the electricity utility people are playing in. Nuclear reactors in brown.
At right is a graphic showing the
SINGLE UNIT relative horsepowers of the energy sources listed below.
(Using the international standard of 746 electrical watts equal one horsepower.)
| Source | Device | Horsepower |
| Vestas V90 Wind Turbine, average power | Vestas V90 Wind | 1,300 |
| Solar Thermal Tower - Brightsource, CA | Solar, Thermal | 27,000 |
| Hyperion TRIGA-like Nuclear MicroNuke | Hyperion MicroNuke | 34,000 |
| Geothermal - West Ford Flat, CA | Geothermal | 36,000 |
| Olmedilla, Spain, World's Largest Photovoltaic Solar System | Solar, Electrical | 80,500 |
| General Atomics TRISO GT-MHR Mininuke | TRISO Prism Mininuke | 400,000 |
| Big Bend (Single Coal Unit, 1 of 4) | Big Bend Coal Unit | 603,000 |
| Modern conventional nuclear power plant | 2009 Nuclear Plant | 2,200,000 |
Typically you will find two to six of the same type source at a single power plant location.
Nuclear fuels
Your generation won't end
Global Warming by doing what your father did
(Right) This is not your father's 1955 uranium pellet
(Left) 1955 era Nuclear Pellet.
WHY TRISO? Conventional reactors were developed about 1955. Their maximum temperature is about 550°F. Not as hot enough to replace a coal fire. A coal-burning power plant runs on 1,000°F steam. A TRISO reactor cruises at about 1,700°F and can easily produce the 1,000°F steam needed by a coal burning power plant. More about TRISO nuclear fuels.
There are also liquid and TRIGA-like reactors that, in some cases, are also hot enough to replace coal.
The author favors the TRISO nuclear fuel reactors for their ability to easily duplicate the coal fires in boilers.
Notable Pebble Bed and Prismatic HTGR Reactors over the entire world
Project
Description
X-10
3.5 MWth US Oak Ridge - 1943
Dragon
20 MWth British - 1964 to 1977
Peach Bottom-1 110 MWth US - General Atomics - 1967 to 1974
http://en.wikipedia.org/wiki/Peach_Bottom_Nuclear_Generating_Station
AVR
15 MWe Experimental pebble bed reactor operated for 21 years in Germany
THTR
300 MWe German pebble bed reactor with steam turbine operated for 5 years
http://www.thtr.de/index.htm
Fort St Vrain 330 MWe US prism
[compacts] HTGR operated for
14 years - General Atomics
Fort St Vrain
HTR-MODUL 80 MWe German modular
pebble bed reactor design by Siemens, 1989
HTR-100
100 MWe German modular pebble bed reactor design by HRB/BBC
HTTR
30 MWth Japanese prism [compacts] HTGR reached criticality in 1998 - Lab unit for hydrogen
production
HTR-10
10 MWth Chinese pebble HTGR reached criticality in 2000 - Lab unit for teaching,
steam generator design projects
HTR-10
HTR-PM
100 MWe Chinese pebble HTGR steam turbine power reactor design for 19-reactor Rongcheng
complex
PBMR
110 MWe South African direct cycle turbine pebble bed design -
Demonstration facility under construction
PBMR
GT-MHR
300 MWe US direct cycle turbine prism HTGR design -
General Atomics joint project with Russia - Electricity from warhead material
GT-MHR
ANTARES GT-MHR 600 MWth French - Russian - Japanese. Prismatic
indirect cycle. H2 + both Brayton and Rankine electric. AREVA, Russian
Institute, FUJI
I know the Russians have built several but I have no project names or specifications.
If you happen to know, please let me know.
A near-precedent for the reactor I'm proposing actually ran in the late 1980s as the German THTR-300 Thorium Reactor (Right). While it was a pebble bed reactor and produced exactly the superheated steam needed for repowering large fossil fuel plants like Tampa's Big Bend to nuclear, it ran largely on thorium rather than uranium and had a dry cooling tower . It provided electricity to the German electrical grid for almost 2 years, most of that time at full power. Under political attack by the Greens, and being something of a prototype and not without its problems, it was shut down, decommissioned, and its planned follow-on, the THTR-500 was never built. http://en.wikipedia.org/wiki/THTR
We have a wonderful pebble bed reactor line-up already. Coal burning power plant units vary in size from less than 50 MWe to over 600 MWe. The "Coal Yard Nuke" system is a 'one-size-can-fit-all' approach using a NRC standardized Westinghouse-ESKOM PBMR 180 MWe pebble bed reactor. I believe no one knows more about how to make a commercially successful circulating pebble reactor than PBMR.
I know almost nothing about the newer design and perhaps more appropriate Chinese HTR-PM. In a 2004 paper, calculations indicated 190 megaWatts electrical of 1,000°F, 2,000 psi superheated steam with feedwater temperature of 400°F. External coolant flow layout resembles the GT-MHR reactor rather than the PBMR.
Other possibilies would be the 325 MWe General Atomics GT-MHR "Prismatic" reactor, and the never-built German THTR-500 MWe reactor. The Russians are in on the GT-MHR and are rumored to have at least one pebble bed in the works in another company. These reactors all combine to provide an initial spectrum of reactor sizes that would repower over 90% of all existing fossil fuel power plant units. The never-built German THTR-500 reactor is closest in size to what I think an ideal big 'Coal Yard Nuke' would be like.
Just grabbing any of these products and running with it would give us a very quick start. The advantage of using a large reactor is that the 5,000 worst CO2 producing power plants identified by the IPCC are the largest power plants in the world. Most remediation for the fewest number of conversions would result from using a THTR-500 size reactor. As it happens, a THTR-500 would be exactly the size needed for a 1 for 1 coal-to-nuclear change-out without loss of electricity at TECO's Big Bend plant.
Closer to our needs in size and temperature but not yet available is a pebble bed that's been under development by MIT's Andrew Kadak. It is a pebble bed that falls between the PBMR and the GT-MHR in size. There is also a Generation-IV Very High Temperature Reactor being developed at the Idaho National Laboratories but it won't be a prototype for several more years.
Demonstration facility: Both the existing Westinghouse-ESKOM PBMR and the General Atomics GT-MHR are already in the Nuclear Regulatory Commission's New Reactor Certifications process, have the sponsorship of United States companies, and have ample capacity for powering at least one of the J. R. Whiting's generators as an initial demonstration facility project.
http://www.iaea.org/inisnkm/nkm/aws/htgr/abstracts/abst_iwggcr15.html IWGGCR-15: Technology of steam generators for gas-cooled reactors.
The pebbles themselves are in very short supply at the moment. PBMR is licensing the German technology which, as I understand it, is a thorium pebble with a dash of uranium. This pebble has the best reputation. I don't know anything about the pebble the Chinese are using in their HTR-10 teaching reactor or their 19 Rongcheng reactors or even if the license PBMR has is exclusive. If the Germans also had a U.S. patent, its 17-year U.S. patent interval would have run out by now, diminishing the value of any multi-national patents on the pebble.
The Chinese pebble bed reactors being designed for China's 19-pebble bed reactor complex at Rongcheng, designated the HTR-PM, are steam producing designs that might ultimately prove to be very technically strong candidates for fossil fuel plant conversion use but, unfortunately, like the German THTR-500, do not currently have a sponsor at the United States Nuclear Regulatory Commission's Reactor Evaluation and Approval Committee - which charges about $250 per bureaucrat hour - adding up to many millions total for a new reactor - according to someone close to the process.
Other Small Reactors:
Smaller Pebble Bed High Temperature, Gas-Cooled Reactors:
A typical coal-burning electricity generating power plant produces between 100 and 400 megaWatts electrical - MWe. Holland's NEREUS and Rod Adam's Atomic Engine fall into the power category of a shipboard diesel engine, about 10 to 30 megaWatts electric, hot enough, but too small by a factor of 10 to power an existing 100+ megaWatt municipal power plant.
Nuclear "batteries"
The 10 to 50 MWe Toshiba's 4S is going to be used in 10 MWe form to power Galena, Alaska. Located on the Yukon River in a remote part of Alaska it will be buried in a silo and it's steam used to heat several main village buildings after passing through the electricity generating turbine.
The 27 MWe, 1,000°F, $25 million uranium hydride Hyperion "Triga-like" reactor is a bit too cool and quite a bit too small to be considered as possible replacements for coal's fire in a typical power plant. Several dozen TRIGA reactors are now operating around the world.
On August 12, 2008, Hyperion Power Generation issued a press release announcing the receipt of a letter of intent (LOI) from TES Group, an investment company that is developing energy projects in Central Eastern Europe. LES intends an initial purchase of 6 Hyperion Power Modules (HPM) at a cost of approximately $25 million per unit. That order might expand to as many as 50 units.
The 45 MWe/150 mWt NuScale (a nascent start-up at this writing) reactor vision appears to be a smaller, more compact version of a conventional reactor. Again, the steam temperatures would be far too low for it to replace a coal burning boiler in an existing power plant.
Liquid Fluoride Thorium Reactors (LFTRs), can run as hot as 1,300°F but, incredibly, no one is interested in them. There is as much thorium as mankind would ever possibly want for the easy taking and it's just dumped into the reactor like ingredients into a soup. http://en.wikipedia.org/wiki/Molten_salt_reactor
Other Small, Medium, and Large Reactors
End Of: The Newer Nuclear Reactors