Nuclear Fusion: Using the energy of the stars on Earth
Slide 2
The Principle
Slide 3
Collision: Deuterium and Tritium
Slide 4
How is it made? In Stars: The gravity pressure makes the atoms
close enough for the fusion. The high temperatures keep the plasma
state making the collisions easier. On Earth: The super gravity of
the stars cant be reproduced, so the temperature must be risen a
lot, about ten times the suns center. The atoms will move so fast
the collision and fusion will happen.
Slide 5
The Process Exactly the opposite of the conventional fission
energy, with some advantages over it: the radioactive nuclear waste
has low intensity and vanish in a few years, beyond that, theres no
risk of disasters As the fission, represents no harm for the
nature
Slide 6
Why its not used? No nuclear reactor until now has made it to
produce more energy than the needed for its running. The first
prototype with chance to achieve this goal is the ITER
(International Thermonuclear Experimental Reactor) which is being
build in France since last year.
Slide 7
Difficulties - ITER The difficulties start with the lack of
tritium on earth, its estimated that there are only 20 Kg of this
isotope. The solution found was put the machine itself to produce
it, they will try to use lithium, once when the energized neutron
hits it, tritium is liberated.
Slide 8
ITER - Temperature Three systems will be used to reach the
required temperature: First neutral particles are injected in high
speed The second will emit radio waves in different
frequencies,similar to micro-waves ovens And the third will use a
beam of eletromagnetic radiation to make hot the electrons inside
the machine.
Slide 9
Keeping the temperature However, none of this will work if the
plasma touch the internal structure of the machine. The trade of
heat between the wall and the hydrogen would cold the last one,
stopping the whole process Thats why it represents no risk, if
anything fails the machine turns off.
Slide 10
ITER The reactor model to avoid this contact used in ITER is
called tokamak.Its used nowadays in JET, the reactor that was used
as a base for ITERs project. It has the shape of a tyre, with
vacuum and a strong magnetic field, 200 000 times the earths one.
This will keep the plasma far from the structure walls
Slide 11
ITERs Scheme
Slide 12
Alternatives of fusion In USA we have two inertial fusion
reactors: The laser beams, where 192 laser beams hit a small ball
the size of a pea, fusing the atoms inside. Electrical chock used
in the Z machine: electrical discharges of high power to make the
fusion
Slide 13
Alternatives of fusion And the Stellarators, in Japan, who
works as the tokamaks, the difference is in the spiral shape which
distributes better the magnetic field.
Slide 14
Future ITER will be ready in 8 years time, its expected to
produce ten times more energy than it consumes. If it succed,the
project of Demo, the first fusion reactor with commercial goals,
will start, its predicted to be operating in 2040.