Download Alternative approaches to fusion energy

Alternative
approaches to fusion
energy
NI T HIN R A MU
Overview
• Lockheed Martin compact fusion reactor
• Working
• Magnetic mirror
• Two mirror sets, diamagnetic cusps, superconducting magnets
• Prospects
• Tri Alpha compact toroid
• Working
• Field reversed configuration, aneutronic fusion
• Prospects
• Z Machine
• Working
• Prospects
Lockheed Martin Compact Fusion Reactor
Compact Fusion Reactor: Magnetic Mirror
• Charged particles moving perpendicular to a
uniform magnetic field move in a circular
path perpendicular to the magnetic field due
to the Lorentz Force
• Radius of circular motion inversely
proportional to magnetic field strength
• If a component of the charged particle’s
velocity is parallel to the magnetic field, the
resultant trajectory will be helical
• At some point, the magnetic field lines will
change direction
• A component of it will decelerate the charged
particle
• Two magnetic mirrors can be used to confine
a charged particle
Compact Fusion Reactor: Working
• Two mirror sets
• A pair of ring mirrors is placed inside
the cylindrical reactor vessel at either
end
• Other mirror set encircles the reactor
cylinder
• The ring magnets produce a type of
magnetic field known as a
diamagnetic cusp, in which magnetic
forces rapidly change direction and
push the nuclei towards the midpoint
between the two rings
• The fields from the external magnets
push the nuclei back towards the
vessel ends.
Compact Fusion Reactor: Working
• Magnetic field strength is an increasing
function of distance from the center
• As plasma pressure causes plasma to expand, the
magnetic field becomes stronger at the plasma
edge, increasing containment
• Higher Beta
• Economical
• Employs superconducting magnets.
• Allow strong magnetic fields to be created with less
energy than conventional magnets
• Has no net current
• eliminates the prime source of plasma instabilities.
• Has a favourable surface-to-volume ratio, which
improves confinement.
• The plasma's small volume reduces the energy
needed to achieve fusion.
Compact Fusion Reactor: Prospects
• Compact
• Should fit on the back of a truck
• Small size shortens the development cycle
• Each design iteration is shorter and lower cost than large-scale projects like ITER
• Possible to make riskier design choices
• Can incorporate new knowledge into the design cycle
• Produce 100W of power
• Enough to power a town of 100,000 people
• Commercial fusion power possible by 2040 worldwide (2080 for projects such as
ITER)
• Many scientists sceptical as very few details released
C2: Field reversed configuration
• Little to no toroidal field
component
• Confined solely by a poloidal field
• Lack of a toroidal field means
high beta
• makes the FRC attractive as a
fusion reactor
• uniquely suited to aneutronic fuels
because of the low required
magnetic field
• More economical
C2: Aneutronic fusion
• Neutrons carry less than 1% of total released energy
• Other fusion reactions release up to 80% of their energy in neutrons
C2: Working
(https://www.youtube.com/watch?v=ezluaNMzHjE )
C2: Prospects
• Advantage of less neutron radiation
• Less ionising damage
• Neutron activation
• No biological shielding, remote handling needed
• Criticism
• Overly fast relaxation time in highly nonthermal plasmas could lead to much less fusion
gain than expected
Z Machine
C2: Inertial confinement fusion
1.
Laser beams or laser-produced X-rays rapidly heat the surface of the fusion target, forming a
surrounding plasma envelope
2.
Fuel is compressed by the rocket-like blow off of the hot surface material
3.
During the final part of the capsule implosion, the fuel core reaches 20 times the density of lead
and ignites at 100,000,000 ˚C
4.
Conditions necessary for fusion reached
Z Machine: Working
• In a Z-pinch machine the wires (right)
are replaced by a plasma
• can be thought of as many current-carrying
wires
• The contraction is counteracted by the
increasing gas pressure of the plasma
• Normally arranged by placing the
plasma vessel inside the core of a
transformer, arranged so the plasma
itself would be the secondary
• In Z-pinch machines the current is
generally provided from a large bank of
capacitors and triggered by a spark gap
• Z-pinch devices are inherently pulsed in
nature.
Z Machine: Prospects
• Ultra-high temperatures reached in 2006 (2.66 to 3.7 billion kelvins)
are much higher than those required for the classical hydrogen,
deuterium and tritium fusion previously considered
Conclusion
• Offer much more fast way to fusion energy for all
• More compact reactors
• Decentralised power sources could be used in developing countries
• Energy for all
• Faster development cycles, improvements
• Maybe worldwide fusion availability by 2040 instead of 2080
• Much cleaner energy
• Aneutronic fusion
• No radiation problems
• Many unknowns about the viability of these projects; they are still clouded
in secrecy