Skip to main content

Nuclear Fusion and Imploding Porcupines

When the sun makes energy through nuclear fusion, it has the benefit of not having to pay real cash for the energy expended to make more energy. Here on Earth, the effort to make fusion energy affordable and practical has been a lot tougher, though the payout is potentially so great – and the benefits manifest - that much effort has gone into it.

Every now and then we get a peek into the fusion world, which is almost always almost ready to almost produce a plausible reactor. And this will happen – I’m sure of it – someday.

To create fusion reactions, the NIF [National Ignition Facility] scientists fire lasers into a hohlraum, or a hollow cylinder made of gold. The laser pulses, lasting billionths of a second, hit a tiny sphere that is full of deuterium (hydrogen with an extra neutron) and tritium (hydrogen with two extra neutrons).

As the laser beams hit the hohlraum, the gold emits X-rays that are so powerful they vaporize the metal surface of the sphere. That vaporization puts immense pressure on the deuterium and tritium, and induces fusion, smashing the hydrogen atoms into helium, plus one neutron.

This is very basically what the sun does, minus the hohlraum and gold, but featuring hydrogen and helium. But this part isn’t where the economics begin to work. This is:

The problem is that even tiny imperfections in the surface of the sphere will mean the pressure on the deuterium and tritium isn't perfectly even all the way around. Result? "It implodes like a porcupine," Edwards told LiveScience. This uneven "reverse explosion" results in energy waste so that more energy is put into the system than comes out of it.

Well, that’s an unfortunate metaphor. Do porcupines implode? We hope the National Ignition Facility’s John Edwards didn’t find a way to do that in a previous job.

This is the kind of sentence we’re used to in fusion stories:

Right now, the amount of energy coming out of the NIF setup is about 80 percent of what is put in.

That’s like the sun, too, though the sun doesn’t need to worry about break-even. Jesse Emspak’s story goes further to express the perpetual doubt about fusion, but, like so many others, including myself, he hopes for the best:

Still, Edwards is optimistic. "Our goal is to demonstrate that ignition is feasible," he said. "We've made a huge amount of progress, and we're close to achieving what our calculations say should be happening in a regime slightly less demanding than full-up ignition implosions."

“Close to achieving.” Let’s look forward to the day when that phrase and fusion are not logically linked. The whole story’s worth a read.

Here’s the Web site for NIF – it’s part of Lawrence Livermore National Laboratory in California. On its homepage, it points out that Star Trek: Into Darkness was filmed there, so there’s that. Here’s its page on fusion if you’d like to learn more.

Comments

jimwg said…
Re: "On its homepage, it points out that Star Trek: Into Darkness was filmed there, so there’s that."

I believe segments of the original "Tron" was filmed there too long before. ("Wow, that's a Big door!...")

James Greenidge
Queens NY
Nick said…
Hi Mark Flanagan,
Great article and well written.
Mark, if the shell isn't evenly coated, here is a suggestion.
In the early 70's our government needed to extremely perfect circular ball bearings.
At the time, there was only one solution. Manufacture these in the weightlessness of space.
The first few tries were a huge improvement, but weren't good enough.
Yet in less than 3 years, the world's most perfect ball bearings were being produced at a very lower cost for their need.
So encapsule and then encoat the burnable shield in the same weightlessness.
And today, it doesn't have to be done in space.
Just a suggestion.
Sincerely,
Nick Negoescu

Popular posts from this blog

Sneak Peek

There's an invisible force powering and propelling our way of life.
It's all around us. You can't feel it. Smell it. Or taste it.
But it's there all the same. And if you look close enough, you can see all the amazing and wondrous things it does.
It not only powers our cities and towns.
And all the high-tech things we love.
It gives us the power to invent.
To explore.
To discover.
To create advanced technologies.
This invisible force creates jobs out of thin air.
It adds billions to our economy.
It's on even when we're not.
And stays on no matter what Mother Nature throws at it.
This invisible force takes us to the outer reaches of outer space.
And to the very depths of our oceans.
It brings us together. And it makes us better.
And most importantly, it has the power to do all this in our lifetime while barely leaving a trace.
Some people might say it's kind of unbelievable.
They wonder, what is this new power that does all these extraordinary things?

A Design Team Pictures the Future of Nuclear Energy

For more than 100 years, the shape and location of human settlements has been defined in large part by energy and water. Cities grew up near natural resources like hydropower, and near water for agricultural, industrial and household use.

So what would the world look like with a new generation of small nuclear reactors that could provide abundant, clean energy for electricity, water pumping and desalination and industrial processes?

Hard to say with precision, but Third Way, the non-partisan think tank, asked the design team at the Washington, D.C. office of Gensler & Associates, an architecture and interior design firm that specializes in sustainable projects like a complex that houses the NFL’s Dallas Cowboys. The talented designers saw a blooming desert and a cozy arctic village, an old urban mill re-purposed as an energy producer, a data center that integrates solar panels on its sprawling flat roofs, a naval base and a humming transit hub.

In the converted mill, high temperat…

Seeing the Light on Nuclear Energy

If you think that there is plenty of electricity, that the air is clean enough and that nuclear power is a just one among many options for meeting human needs, then you are probably over-focused on the United States or Western Europe. Even then, you’d be wrong.

That’s the idea at the heart of a new book, “Seeing the Light: The Case for Nuclear Power in the 21st Century,” by Scott L. Montgomery, a geoscientist and energy expert, and Thomas Graham Jr., a retired ambassador and arms control expert.


Billions of people live in energy poverty, they write, and even those who don’t, those who live in places where there is always an electric outlet or a light switch handy, we need to unmake the last 200 years of energy history, and move to non-carbon sources. Energy is integral to our lives but the authors cite a World Health Organization estimate that more than 6.5 million people die each year from air pollution.  In addition, they say, the global climate is heading for ruinous instability. E…