‘Twas the Week Before Christmas
‘Twas the week before Christmas and all through the land
There was news about Fusion – exciting and grand
A breakthrough of major proportions was here
No more need to warm up our atmosphere!
When what to my wondering eyes did appear
But a miniature sleigh with eight tiny reindeer
And a guy flinging fusion gifts throughout the sky!
Oh, I get it, I said – I’m just very high.
The news about nuclear fusion research achieving an exciting milestone was timed perfectly to end our year on a note of cheer. There’s nothing wrong with cheery news, as long as we understand it well enough to know how to react!
We’ve understood hydrogen fusion to be the primary energy source of the sun and recognized its potential since 1920. It was successfully re-created in the lab in 1932. Fusion was proposed as a domestic energy source in 1941 and tested experimentally in 1952. As a bomb. That bomb was 450 times as strong as the fission bomb dropped on Nagasaki. Oops! Controlling this reaction has been a problem ever since.
In the late 1950s, experiments began to try to harness this extremely dense energy source in a controlled way. Back then it was claimed that the technology would lead to controlled fusion in 30 years. The joke has been that for the past 65 years, controlled fusion has been 30 years away. Now with this breakthrough, we can look forward to controlled fusion being 10 years away for the next 30 years!
The main difficulty with controlled fusion is that the temperature required to initiate the reaction is over 100 million degrees. Finding a container for the reaction is therefore problematic. One of the attempts at solving this has been magnetic confinement in a device called a tokamak. This is a donut-shaped vessel in which very strong and carefully controlled magnetic fields suspend the very hot plasma (a gas of ionized hydrogen). The past 65 years have shown this to be considerably more difficult than originally predicted.
Another approach to controlling fusion is “inertial confinement.” This week’s announcement of net energy from fusion uses this technology, also not new; it’s been around since the 1970s. In this case, a small peppercorn-size “fuel” pellet of hydrogen isotopes contained in a perfectly spherical metal container is squeezed by the most powerful lasers in the world. The squeeze can produce temperatures of over 100 million degrees C, potentially initiating the fusion reaction.
What happened this week is that for the first time, more energy was released in the fusion reaction than the energy of the laser beams that were used. The reaction lasted less than a billionth of a second and the total energy produced might be enough to cook a meal.
How do nuclear fusion and nuclear fission compare? Fission means “splitting,” and fusion means “combining.” In our nuclear power plants, a fission reaction splits a uranium atom into two new, smaller atoms such as krypton and barium. The mass of the two products is ever so slightly less than the original uranium atom. (You’ve probably seen this before: E=mc²). That tiny mass difference is converted into thermal energy which is used to make steam to run a turbine which turns a generator that produces electricity. This one reaction produces more than a million times as much energy as a comparable chemical reaction.
The waste material from nuclear fission plants is highly damaging to living things, the fuel itself can be used by bad guys for bombs, and all the dangerous stuff lasts forever; even if people want them in their backyards, nuclear power plants take decades to construct.
In a fusion reaction, elements fuse into a heavier element. In certain cases, energy is released in this reaction. By far the most common fusion reaction is when 2 hydrogen isotopes fuse to form helium. This reaction produces about 3 million times more energy than a typical chemical reaction.
The vision is for nuclear fusion to emanate from fusion reactors that run on “heavy hydrogen,” called deuterium, producing carbon dioxide-free and virtually limitless power for all the world forever, with very few waste products. This is what the sun has been doing for five billion years. It’s gotten us this far but now that our energy demands have outpaced our ability to use it safely (thanks to draining the fossil fuel bank account it set up for us), we are attempting to “steal fire,” for our own fusion – quite the heist!
Here’s a thought: Let’s celebrate this week’s breakthrough by focusing more than ever on curbing carbon emissions, so that when this magical source of energy becomes available, we have a livable world to use it in!
Down the chimney came Santa, all covered in soot
“You won’t need that with fusion,” he laughed with a hoot!
“But don’t hold your breath til it turns on your lights
Just keep curbing emissions, keep fighting the fight!”
He left normal presents, no fusion, no gold
He went up the chimney, yelling into the cold
“Merry Christmas to all and to all a good night!”
Pretty sure that mushroom was magic, all right.
Paul Stancioff, PhD., is Professor Emeritus of physics at UMF. Cynthia Stancioff keeps him and her busy. Email: pauls@maine.edu or cynthia.hoeh@gmail.com Previous columns can be found at https://
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