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Posted by on Jan 10, 2014 in Science | 3 comments

Fusion Power

Fusion power is something of a pipedream/golden bullet/panacea for our energy problem woes. If it can ever be made to work, then it will be much better than anything else in existence. Almost no radiation, none at all when the reactor isn’t running, and the vessel would be radioactive for about 100 years, unlike fission plants. No fuel based pollution, unlike fossil fuels. Runs 24/7 no matter the weather, unlike solar and wind power. Doesn’t take up space needed for other things, unlike biofuels.

This sounds awesome. So what’s the catch? Well, they are really hard to build, get energy out of, and,of course, really expensive.

One of the major hurdles with fusion power is that has to be overcome is that until just last year, we always had to put more energy into the reactor than we could get out of the reactor.

To make fusion work, we have to create conditions nearly equivalent to the inside of the sun. Inside the reactor vessel, we have to heat a mixture of hydrogen isotopes to about 150 million degrees Celsius. Then we have to contain the plasma and keep this superhot mixture both under pressure and from actually touching anything (like the reactor walls or air). These are three major power drains. Create a maintain a vacuum. Create and maintain a magnetic field. Create and maintain 150 million degrees Celsius.

The current estimate by the ITER project is that it will take 50 Megawatts of power to get the fusion reactor running. If the system doesn’t generate more electrical energy than that, it’s a waste of time.

August 26th of last year, that important milestone was reached by the US National Ignition Facility. But it was a completely different design than what I just described. The NIF used 192 lasers that all fired so as to hit a small pellet of deuterium (a hydrogen isotope) simultaneously (and I mean exactly at the same time) with over 350 Terawatts of peak in five millionths of a second.  For that one moment in time, more energy was produced than went into the lasers.

The ITER project plans to use 50 Megawatts of power to be able to continually produce 500 Megawatts of power.

Seven member countries are involved in the ITER project.  They are China, the European Union, India, Japan, Korea, Russia, and the United States. After the ITER fusion plant is up and running (around 14 years from now), the consortium will build DEMO, which is intended to be an operational powerplant that will actually provide electricity.  If that project goes well, then we could begin to see operational fusion power plants maybe by 2035 (when I’m into my 60s).

Like many things in the world. There are several ways to do something. Some ways are very difficult, but can provide enormous benefits. Some ways are easy, but have major drawbacks. It’s time to start doing things the hard way, so the easy way doesn’t damage our planet any more.

Some more resources on fusion projects:

ITER - a consortium of seven countries building a working fusion powerplant in Southern France.

NIF – the US National Ignition Facility

EFDA – The European Fusion Development Agreement

  • KeithB

    Don’t forget Sandia:

    https://share.sandia.gov/news/resources/news_releases/fusion_instabilities/

    Are you sure about the 100 years? Neutron capture will make a lot of the reactor radioactive even if it was non-radioactive to start. It depends on what materials the reactor is eventually made of. I do know that neutron irradiated gold generates isotopes with short halflifes.

    • SmilodonsRetreat

      Sandia is doing research for the ITER, not doing their own fusion reactor. That’s why I didn’t include them.

      As far as the 100 year thing, that’s directly from ITER. I’m not a physicist working with radioactivity. From what I have read, the fusion reactors use slow neutrons to heat water, roughly the same as a fission reactor. The neutrons do interact with the vessel itself and it will eventually be classified as low level nuclear waste and half to be replaced. There seems to be much research looking into what materials can handle the thermal and physical loads and still be “resistant” to neutron induced radioactivity.

  • wtanksleyjr

    Also, don’t forget Bussard’s fusion reactor, the Polywell. http://en.wikipedia.org/wiki/Polywell. That’s a derivative of Farnham’s fusor, the type of reactor you read about people building in their garage.