Tri Alpha Energy, Inc.

Organization

As of 2014, TAE is said to have more than 150 employees and raised over $150 million, far more than any other private fusion power research company or the vast majority of federally-funded government laboratory and university fusion programs. Main financing has come from Goldman Sachs and venture capitalists such as Microsoft co-founder Paul Allen's Vulcan Inc., Rockefeller's Venrock, Richard Kramlich's New Enterprise Associates, the Government of Russia, through the joint-stock company Rusnano, invested in Tri Alpha Energy in October 2012, and Anatoly Chubais, Rusnano CEO, became a board member.

Field-reversed configuration

The field-reversed configuration (FRC) confines heat created by the fusion reaction by utilizing ion beams, inside a cylindrical, truck-sized vacuum chamber containing solenoids.

After years studying ion beam heating of various FRCs, most recent research suggests they are considering the acceleration of compact toroids at high speed from each end of a long reactor, merging as an FRC in the middle, in order to improve ion heating and confinement lifetime. They use ion beams to further heat the FRC.

Unlike other magnetic confinement fusion devices such as the tokamak, FRCs provide a magnetic field topology whereby the axial field inside the reactor is reversed by eddy currents in the plasma, as compared to the ambient magnetic field externally applied by solenoids. The FRC is less prone to magnetohydrodynamic and plasma instabilities than other magnetic confinement fusion methods. The science behind the colliding beam fusion reactor is used in TAE's C-2, C-2U and C-2W projects.

The 11B(p,α)αα aneutronic reaction

An essential component of the Colliding Beam Fusion Reactor (CBFR) design is the use of "advanced fuels", i.e. fuels with primary reactions that do not produce neutrons, such as hydrogen and boron-11. CBFR fusion products are all charged particles for which highly efficient direct energy conversion is feasible. Neutron flux and associated on-site radioactivity is virtually non-existent. So unlike other nuclear fusion research involving deuterium and tritium, and unlike nuclear fission, no radioactive waste is created. The hydrogen and boron-11 fuel used in this type of reaction is also much more abundant.

Tri Alpha Energy relies on the clean ¹¹B(p,α)αα reaction, also written ¹¹B(p,3α), which produces three helium nuclei called α−particles (hence the name of the company) as follows:

A proton (identical to the most common hydrogen nucleus) striking boron-11 creates a resonance in carbon-12, which decays by emitting one high energy primary α−particle. This leads to the first excited state of beryllium-8, which decays into two low-energy secondary α-particles. This is the model commonly accepted in the scientific community since the published results account for a 1987 experiment.

TAE claimed that the reaction products should release more energy than what is commonly envisaged. In 2010, Henry R. Weller and his team from the Triangle Universities Nuclear Laboratory (TUNL) used the intense High Intensity γ-ray Source (HIγS) at Duke University, funded by TAE and the U.S. Department of Energy, to show that the mechanism first proposed by Ernest Rutherford and Mark Oliphant in 1933, then Philip Dee and C. W. Gilbert from the Cavendish Laboratory in 1936, and the results of an experiment conducted by French researchers from IN2P3 in 1969, was correct. The model and the experiment predicted two high energy α-particles of almost equal energy. One was the primary α-particle and the other a secondary α-particle, both emitted at an angle of 155 degrees. A third secondary α-particle is also emitted, of lower energy.

Inverse cyclotron converter (ICC)

Direct energy conversion systems for other fusion power generators, involving collector plates and "venetian blinds" or a long linear microwave cavity filled with a 10-Tesla magnetic field and rectennas, are not suitable for fusion with ion energies above 1 MeV. TAE employed a much shorter device, an Inverse Cyclotron Converter (ICC) that operated at 5 MHz and requires a magnetic field of only 0.6 tesla. The linear motion of fusion product ions is converted to circular motion by a magnetic cusp. Energy is collected from the charged particles as they spiral past quadrupole electrodes. More classical collectors collect particles with energy less than 1 MeV.

The estimation of the ratio of fusion power to radiation loss for a 100 MW CBFR has been calculated for different fuels, assuming a converter efficiency of 90% for α-particles, 40% for Bremsstrahlung radiation through photoelectric effect, and 70% for the accelerators, with 10T superconducting magnetic coils:

The spin polarization enhances the fusion cross section by a factor of 1.6 for ¹¹B. A further increase in Q should result from the nuclear quadrupole moment of ¹¹B. And another increase in Q may also result from the mechanism allowing the production of a secondary high-energy α-particle.

TAE plans to use the p-¹¹B reaction in their commercial CBFR for safety reasons and because the energy conversion systems are simpler and smaller: Since no neutron is released, thermal conversion is unnecessary, hence no heat exchanger or steam turbine.

The "truck-sized" 100 MW reactors designed in TAE presentations are based on these calculations.

C-2

Various experiments have been conducted by TAE on the world's largest compact toroid device called "C-2". Results began to be regularly published in 2010, with papers including 60 authors. C-2 results showed peak ion temperatures of 400 Electron volts (5 million degrees Celsius), electron temperatures of 150 Electron volts, plasma densities of 1E-19 m⁻³ and 1E9 fusion neutrons per second for 3 milliseconds.

C-2U and C-2W

In March 2015, the upgraded C-2U with edge-biasing beams showed a 10-fold improvement in lifetime, with FRCs heated to 10 million degrees Celsius and lasting 5 milliseconds with no sign of decay. The C-2U functions by firing two donut shaped plasmas at each other at 1 million kilometers per hour, the result is a cigar-shaped FRC as much as 3 meters long and 40 centimeters across. The plasma was controlled with magnetic fields generated by electrodes and magnets at each end of the tube. The upgraded particle beam system provided 10 megawatts of power.

Russian cooperation

The Budker Institute of Nuclear Physics, Novosibirsk, built a powerful plasma injector, shipped in late 2013 to TAE's research facility. The device produces a neutral beam in the range of 5 to 20 MW, and injects energy inside the reactor to transfer it to the fusion plasma.

CBFR-SPS

The CBFR-SPS is a 100 MW-class, magnetic field-reversed configuration (FRC), aneutronic fusion rocket concept. The reactor is fueled by an energetic-ion mixture of hydrogen and boron (p-¹¹B). Fusion products are helium ions (α-particles) expelled axially out of the system. α-particles flowing in one direction are decelerated and their energy directly converted to power the system; and particles expelled in the opposite direction provide thrust. Since the fusion products are charged particles and does not release neutrons, the system does not require the use of a massive radiation shield.

Criticism

Since publishing in 1997, the Colliding Beam Fusion Reactor has been criticized for unworkable conditions that would be caused by overly fast relaxation time in highly nonthermal plasmas, leading to much less fusion gain than expected. The concept was also scrutinized for issues with inevitable energy loss due to frictional heating in the plasma that would lower the fusion gain below any practical value, an overly strong coupling of the ions through the electrons; and an equilibrium issue due to the elongated plasma geometry. TAE founders responded that the critics' simplistic calculations should be replaced by more precise Vlasov and Fokker–Planck equations and development in classical transport theory. The CBFR was evaluated by the Institute for Fusion Studies of the University of Texas at Austin in 2001. The report concluded that "the proton-boron colliding beam fusion reactor is not a viable concept unless technology capable of very high energy conversion efficiencies (no less than 84%) can be developed."