- On December 5th,
scientists produced the world's first fusion
reaction with net energy gain, a major milestone
in the decades-long quest to develop a technology
that could provide unlimited, cheap, clean power. - Simply put, this is one of
the most impressive scientific feats
of the 21st century. - Nuclear fusion is the ultimate
clean-energy dream, the Holy Grail
of carbon-free power that scientists have been
chasing for decades. In fact, experiments with fusion
go back almost as far
as those with fission, with the first fusion bomb
detonated by the US in 1952. - You know, the thing is that
many people have gotten the idea that,
until, you know, December 5th, we didn't know
how fusion worked. No, no, no, no, no, no, no. How fusion works was understood
over 70 years ago. The question is, how to do it
in a controlled fashion, in the laboratory. That was not understood. - So, how did they do it? The breakthrough took place at
the National Ignition Facility, a part of the Lawrence Livermore
National Laboratory in California, researching high-energy science
and nuclear deterrence. The facility is the size
of a sports stadium and has one of the most powerful
laser arrays in the world. And all of it to create
a reaction that lasts less than
a billionth of a second. - So, fusion is a reaction
between two atoms where they come together
to form a heavier atom, and energy is also released
in that process. And the energy that comes out
in that neutron is the energy that we can then harness
to use for other experiments or, potentially,
for fusion energy. There's different ways
of doing this, using magnets or using lasers. Here, we use lasers. They're the result of decades
of research and innovation, and the National Ignition
Facility itself is unique. There's no other facilities
that can deliver the same kind of energy
as the NIF can, currently. - It all begins
with a single pulse. A stream of photons is amplified
and split, again and again, until there are 192 lasers
in total. Their target is a
three-story-high vessel called the target chamber. Inside, the lasers are directed
towards a small capsule called a hohlraum, containing a pellet
of hydrogen atoms about half the size of a BB. As the beams strike, the high
temperature and immense pressure cause the hydrogen atoms to fuse
together and release energy, about 50% more than
what went into it. The reaction creates what
amounts to a miniature star. - It was clear it was going
to be very hard. And they figured it out. It is amazing. It's an amazing achievement. - My first reaction was,
"Oh, my gosh, we did it!" One of our engineers
actually thought that there was something wrong
with our diagnostic system, initially, because the signal
was so much bigger than what we had
anticipated it might be. So, as soon as we started to see
that very early data coming in, our response was, "Oh, my gosh. This is awesome.
We did it." But then, as scientists,
we have to be very careful before we jump to conclusions, so, we went into a period
of more intense analysis of all of the data. - While the possibilities
for fusion are huge, there are a number of challenges
it faces before commercial use. The amount of energy
from the grid, which charged NIF's
large capacitors and created that first laser, was far larger than the net
energy gain from fusion, by nearly one hundredfold. - The NIF was actually built
using 1990's laser technology because that was the time
when we started the project. So, in order to make
this more efficient, essentially,
we need better technology. - Deuterium,
one of the ingredients in the fusion reaction,
is abundant in seawater, but the other isotope, tritium,
a byproduct of nuclear reactors, is harder to come by. - NIF shoots at the power level
that was used on December 5th, roughly speaking, once a day. If you made a fusion reactor that used a similar
kind of reaction, you'd have to shoot
10 times a second, 24/7. You need a lot of pellets, hundreds of thousands
of pellets. They have to be made perfectly, just like the one that was used
was made perfectly. You have this challenge of,
then, how do you actually use the energy that's coming out
to actually produce electricity? - But for all it's obstacles,
there are obvious advantages that scientists are looking
forward to with fusion. - When we burn fossil fuels, we all know that we release
a lot of greenhouse gases that can be harming
to our environment. With nuclear-energy sources,
both fission and fusion, we're not releasing
those same kinds of products, and then fusion has the added
advantage that it's about four times more efficient
per unit mass than fission is, and it's also a much cleaner
source of energy because we don't produce
those radioactive, spent-fuel products
that fission reactors produce. - So, when could fusion
actually power our homes? That's the trillion-dollar
question. Experts argue that it's not
a matter of time but a matter of money. - Ultimately, the decision would
be made at the political level. Money matters, especially when
budgets are being fought about, and, so, I'm not
so sure what will happen. - The success of the experiment
on December 5th, it's sort of like that
Wright Brothers moment where it's a proof of principle. We took the first flight,
you know? That flight wasn't something
that was going to get anyone anywhere,
in terms of actual transport. It was many, many years before
we got to full-scale, you know, commercial travel
by aircraft in the US. I think we're in a similar state
right now with fusion energy, where, probably,
it's going to be at least one to two decades
before we would see a commercially
viable fusion-energy source. But it launched
our understanding. It helped us know that it was
possible.
