Aneutronic Fusion

Nuclear energy has the potential to be weapons and radioactive waste free, but that depends on what process you use. Your choices are:


The ideal choice is aneutronic fusion. (A new...what?) "A" means "without"; "a-neutronic" means without neutrons as a byproduct. What is it about neutrons that makes such a difference? (And what's the catch?)

Fission and the trouble with Neutrons

Fission
Nuclear FISSION
When most people think of nuclear energy, they think of fission. With fission, a neutron splits a large atom into smaller ones, releasing more neutrons for a chain reaction. Control rods are required to soak up extra neutrons to avoid meltdown.

Neutrons make things Radioactive.: The fuel is radioactive, and the byproducts are radioactive. Neutrons change the nature of things they slam into, making them radioactive.
Proliferation:
Then there's the (cough, cough) proliferation problem.
The Result: Steam
The Neutrons in fission generate heat. Heat turns water into steam, to spin a turbine. This generates electricity. So, nuclear power is fuel for an 18th century steam technology.
Note: A bit of perspective here, radiation isn' t as horrible as you might think. Problems with green house gases and the deadly effects of coal and fossil fuels can make the risks of radiation downright attractive. But they don't get rid of the proliferation problem. Advances in fission (i.e. Terrapower and LiFTr) may address some of these issues to some extent. We continue to watch their development. But even if they solve the radioactivity and proliferation problem - fission will still be producing heat for a glorified steam engine. So inefficient. So 18th century.

Conventional (neutronic) fusion - DT

Nuclear FUSION has the potential to generate power without the radioactive waste of nuclear fission, but that depends on which atoms you decide to fuse. Conventional fusion approaches work with deuterium and tritium, while aneutronic fusion works with other fuels. When deuterium and tritium fuse, they yield an alpha particle and a neutron.
deuterium
Deuterium
Deuterium is Hydrogen (a proton) with an extra neutron.
tritium
Tritium
Tritium is hydrogen with two extra neutrons. It doesn't occur in nature. It's rare, super expensive, radioactive and has proliferation dangers. A key challenge of neutronic fusion is how to breed tritium.
Deuterium Tritium fusion
Neutronic Fusion
When deuterium nuclei fuse with tritium, they form an alpha particle (harmless Helium ion) and a neutron. Yes, that pesky neutron. The radioactive waste from fusion is less than fission, and shorter lived. But it is not eliminated.
steam
Energy Output
The neutron generates heat which needs to be captured somehow and will likely heat water and produce steam to spin a turbine... Here again we have Space age technology to power 18th century steam engine.

Aneutronic Fusion: the best is yet to come.

1H + 2 6Li →
1H + 7Li →
3He + 3He →
1H + 11B →

Aneutronic Candidates
Aneutronic fusion is fusion that does not produce neutrons as a product of the reaction.

There are several element combinations that can be used in aneutronic fusion. We'll look at the most likely one here: 1H + 11B aka pB11.

Note: H stands for hydrogen. A hydrogen nucleus is a single proton, hence "p" for proton also refers to hydrogen.
proton Boron fusion
Proton Boron (pB11)
When a boron-11 nucleus fuses with a hydrogen nucleus - the result is three helium nuclei (aka "alpha particles") and energy, but no radioactive waste.
electricity directly
Electricity Directly
But wait! If there are no neutrons produced, where do you get heat for the steam engine?

You don't. The Helium ions coming out are positively charged - it's electricity directly.

This is a space age fuel that finally cuts the umbilical cord of steam.

Awesome! Where can I get my Aneutronic Fusion?

There's a catch, of course. Aneutronic fusion is difficult to achieve. It requires an order of magnitude higher temperatures than neutronic fusion (it's very HOT fusion). Humanity hasn't figured out how to harness it yet.

It's an awesome, burning energy challenge. A lot of people think it can't be done. They don't have much confidence in their fellow human beings. The physics - daunting. Perhaps even more difficult - the finances, the collective action problem to get adequate resources to mount a thorough investigation of this challenge.

Luckily, there are some scientists boldly exploring the frontiers of aneutronic fusion, including the crew working on the LPP Experiment. These projects need our support, they need our encouragement and they need our conscious commitment.

There are many reasons to pursue aneutronic fusion. You may be in it for the energy, or for saving the world, or for getting rid of nuclear weapons. On top of those practical reasons, this is about downloading the power of the stars, stealing fire from the gods, redeeming nuclear power. It's about showing the universe what we're capable of.

Recent posts in this category

 

Future City Winners!

Feb 10, 2012

Congratulations to Team Xiwang, (Cambrie Hickman, Rachel Fisher, Jessie Friedman and Timothy Graunke)  on winning the Arizona Future City Competition!  And a big Thank You to the team for running their city on aneutronic fuel, dubbed “HB Fuse”!


Duke Researchers Offer insight into Aneutronic fusion

Apr 05, 2011

Thanks to Dan619 for telling us about this: “Understanding the 11B(p,a)aa reaction at the 0.675 MeV resonance”, S. Stave et al, Physics letters B, December 2010.  (pdf file)


What are neutrons?  And what do we have against them?

Jan 14, 2011

Aneutronic means “no neutrons” - does this mean we want to eliminate neutrons?


Posters to kick off fusion conversations

Oct 28, 2010

Ever wonder how to explain Focus Fusion to someone?  Ever find yourself starting with the device, and realizing you have to backtrack and explain a whole lot of other stuff first? 

Here are some posters to help you with that.


pB11 Art Project

Oct 11, 2010

Thank you to Derek Shannon for decorating the LPP lab walls with a schematic representation of proton boron fusion made from paper plates and mixed media.  Now to get every school kid in America to do this sort of thing.  A great way to explain aneutronic fusion!


The Stagecoach and the Spaceship

Apr 23, 2010

Thanks to a PPPL physicist, we have a handy metaphor to distinguish DT fusion from aneutronic fusion.  This isn’t about any fusion devices, but rather the fusible material itself - the fuel.


Fusion Concept Monitor beta

Apr 21, 2010

Wondering what to do on Earth day to promote fusion?  Try out the “Aneutronic Fusion Concept Monitor - beta” (pdf file).


Aneutronic Fusion Candidates

Dec 03, 2009

“A” means “without”.  Therefore “a-neutronic” is “without neutrons”.  Aneutronic fusion means fusion that does not seek to produce neutrons as a by-product.


Neutron safety applications

Feb 07, 2009

The Focus Fusion approach to generating energy limits the creation of neutrons.  In fact, we essentially eliminate them.  Just because we avoid neutrons doesn’t mean we think they’re evil.  In fact, there are some cool uses for neutrons.  There is, for example, the neutron bath method being developed by Livermore scientists to scan cargo suspected of carrying fissile material.


The Trouble with Tritium

Jul 15, 2006

$200 Million per kg.
27 kg and decaying.


Can Focus Fusion be used to make a fusion bomb?

Jul 14, 2006

Energy and Security

Jul 14, 2006

Energy and security intersect in many different ways.


How does the Helium from focus fusion turn into Electricity?

May 15, 2006

Are you sure p-B11 fusion isn’t fission?

May 14, 2006

Focus Fusion vs. Nuclear Reactors

May 13, 2006
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