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| JT-60SA tokamak nuclear fusion facility outside Tokyo, Japan. JT-60SA.org |
The
old joke is that fusion is always 50 years away. Unlike fission which
breaks up atoms and results in dangerous radioactive waste, fusion
pushes atoms and their subatomic particles together, mimicking the
process that happens on our nearest star and nuclear reactor, the Sun.
This results in conversion of matter to energy and a tremendous release
of heat (thermal power stations use that heat to boil water and make
steam, which drives turbines to spin the alternators that make
electricity). Fusion produces minimal radioactive waste and unlike a
fission reaction which can go out of control and result in a explosion
as happened in Chernobyl, it's inherently safe because of the conditions
required to sustain fusion: high temperature and pressure. If these
conditions aren't sustained, the reaction safely fizzles out. While the
Sun finds it "easy" to sustain a fusion reaction, due to the immense
gravity that squeezes hydrogen atoms together and forms helium as a
waste product, creating the conditions for fusion in a reactor on Earth
is a huge technical challenge. Up until recently, more energy has been
required to create the required high temperatures and pressure than the
net energy that could be generated by a fusion reaction. According to
Popular Science, in 2023, "the National Ignition Facility (NIF) at
Northern California’s Lawrence Livermore National Laboratory achieved a
net energy gain for the second time using what’s the inertial
confinement fusion method".
The fuels for fusion reactors are tritium or deuterium, both isotopes of hydrogen.
This article from Popular Science, published in Dec 2023, informs us that the world’s largest experimental tokamak nuclear fusion reactor is up and running.