- 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.