Major Thorium Fuel Reactor Progress

The first firm we’ll look at is Flibe Energy, a new company that will develop small modular reactors based on liquid-fluoride thorium reactor (LFTR) technology.  Flibe Energy is a new company founded by Kirk Sorensen who was (is still?) chief nuclear technologist at Teledyne Brown.  The second is Thorenco LLC, founded by Charles S. Holden with support from Berkley National Laboratory and others.

Sorensen’s company is called “Flibe” from lithium fluoride (LiF) and beryllium fluoride (BeF2) that together form a solution often called “F-Li-Be”.  Liquid-fluoride thorium reactors operate at high temperatures but not at high pressures because they use a chemically stable medium as the fuel and the coolant, making them much safer to operate than conventional reactors.

That temperature and pressure matter is important.  In a liquid fluoride thorium reactor as hot as it is can only get so hot before the fuel melts out a plug that drains the fuel out into a diluted and non-reactive state to cool.  With out the high pressures the potential for an explosion is missing.  What could explode would be the steam on the other side of the heat exchanger – but that risk is in any power station from natural gas fired, to coal and on to a uranium reactor.

The other main point is the primary fuel in the solution is thorium.  Thorium is abundant compared to uranium and doesn’t ratchet up in the reactor to weapons materials like plutonium.  These points should, if people would pay a bit of attention, form a firm base for thorium fueled reactor progress.

The root of Sorensen’s technology comes from Nobel-Prize-winning physicist Eugene Wigner and his protégé, Alvin Weinberg, who attempted to convince the US government to research the surpassing potential of thorium after World War II.  In 1955, Weinberg took charge of the Oak Ridge National Laboratory in Tennessee and began a personal campaign to try to realize the benefits of thorium. Under his leadership, two prototype nuclear reactors were built that demonstrated key technologies needed to bring thorium energy generation to reality.

Many believe, with good reason, that the lithium fluoride and beryllium fluoride salt fission reactor is the ideal medium for nuclear chemical processing and reactor operation. It is chemically stable, nearly invisible to neutrons, and impervious to radiation damage, unlike almost every other nuclear fuel. A flibe-designed reactor carries large amounts of heat at low pressures, leading to small, compact, and safe designs for nuclear reactors.

The Flibe proposal is to build small reactors to supply affordable and sustainable electrical energy, desalinated water, synthetic hydrocarbons, ammonia, and lifesaving radioisotopes.

Thorenco LLC is proposing small transportable 50-megawatt-thermal thorium converter reactors for multiple uses: producing electricity and low-cost, high-temperature steam for process industrial heat. The high-temperature steam can be used for extraction of oil from tar sands, or desalinating, purifying, and cracking water. The reactor’s fuel matrix can be “tuned” to provide the right output for each particular work process.

The Thorenco designed core in the newest design is a short wide cylinder at about 140 centimeters (56 inches) in diameter and 50 centimeters (20 inches) tall. That size makes for portability, such that it can be brought to remote locations to a work site and supply heat and electricity there without dependence on long-distance transmission lines and moved, as conditions require. The small size would be factory-built and transported to its destination, “plugged in” to a deep underground containment structure, and put to work quickly. The core can be shipped back to the factory when the fuel needs to be changed.

The Thorenco fuel is quite different from the typical liquid fluoride thorium fuel.  Thorenco would use fissile uranium-235 as a source of ignition neutrons and a mix of thorium tetrafluoride in a beryllium fluoride molten salt, which dispersed in an inert metal matrix covered by Holden’s Patent Cooperation Treaty application, and is pumped in circulation.  The metal matrix is a solid-state metal alloy composed of four materials. The thorium and uranium fuel particles are embedded in the alloy, which both slows and moderates the fissioning process. There are moderating materials dispersed in the alloy along with the actinide particles. Using the metallic alloys as moderators (instead of the water used in other thorium reactor designs) allows Thorenco’s reactor to operate in a more energetic neutron spectrum so that its core can have a long life.

The Thorenco design with its moderator built in makes the self-regulating reactor’s fuel term to operate for 10 years without needing refueling.

These two plans put a new energy into the U.S. thorium fueled fission business.  With India and of late China, racing to bring reactors to market, it’s not a moment too soon.  The problem still lies in getting some motion out of the U.S. government’s regulatory apparatus.

Getting public acceptance going isn’t going to be so hard.  The big issues, exploding and throwing out huge plumes of radioactivity, meltdowns burning holes in the planet, and weapons proliferation just aren’t applicable in any worthwhile way.  That’s not to say those kinds of fear mongering aren’t going to happen, its just that the audience could be limited to the fewest intellectually lacking or emotionally vulnerable with a little honesty from industry, government and the media.

While starting companies isn’t technology news, and the ideas from these two firms isn’t new, the backing of the two firm is worth noting and that they are active now is cause for some celebration.  Congratulation to all involved and thanks to Brian Wang and EnergyFromThorium.com for getting the word out.

Read more at New Energy And Fuel

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