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The author's assertion that this project will be impacted by the Japanese disaster shows that she doesn't understand the technology. Fusion != Fission, and in t

The author's assertion that this project will be impacted by the Japanese disaster shows that she doesn't understand the technology. Fusion != Fission, and in this case there isn't even any radioactive material in the equation. If anything, the Japanese disaster will put more focus on fusion research and development. /facepalm

cperciva 16y ago
Fusion != Fission, and in this case there isn't even any radioactive material in the equation Fusion reactors spew neutrons which can create a variety of radioactive isotopes. Most of these are very short-lived, fortunately -- but they do exist, and reactor designs need to take these into account. (Also, some reactor designs use tritium as fuel, which is of course radioactive to begin with.)
- DennisP 16y ago
  True but the other difference is that fission reactors have to be kept cool. With fusion reactors, the challenge is getting it hot enough. There's never a concern about loss of cooling, meltdown, all that mess. Also of course, several projects are attempting boron fusion, which doesn't produce neutrons other than from a small portion of side reactions.
  - cperciva 16y ago
    Right, I agree that fusion reactors are inherently much safer than fission reactors -- I just wanted to make the point that they're still not completely harmless.
- hugh3 16y ago
  Related anecdote: I visited the National Ignition Facility [1] last year, where everything was pretty much up and running but they still hadn't finished putting in all the shielding that needs to surround the target chamber before they start actually doing fusion shots. We were assured that if they had done a fusion shot before installing the shielding then everyone in the (extremely large) building would have been dead due to (if I recall correctly) neutron absorption. Side note: the National Ignition Facility is freaking awesome. [1] http://en.wikipedia.org/wiki/National_Ignition_Facility http://en.wikipedia.org/wiki/National_Ignition_Facility
- jeffreymcmanus 16y ago
  It's worth mentioning here that coal-fired power plants also spew radioactivity into the atmosphere.
  - lispm 16y ago
    Especially old coal power plants which have not upgraded with filters...
    - billswift 16y ago
      Actually, a large part of the radioactivity is in the form of C-14 in carbon dioxide which is unaffected by filters.
      - lispm 15y ago
        'Large part'? Numbers, please. C-14 is not much contained in old fossil fuels due to radioactive decay. The literature also discusses the Suess effect, which shows that coal power plant reduced the effect of C-14.
neutronicus 16y ago
That's not exactly true. There's enough neutron flux in a hypothetical fusion reactor (assuming D-T) for neutron activation of structural materials to be a real concern. There are actually some hybrid fission-fusion designs which use a fusion reactor running at a loss as a neutron source for a subcritical assembly of fission fuel. You're right that the fission products and high-mass-number alpha emitters have left the picture, though.
rimantas 16y ago
The author's assertion that this project will be impacted by the Japanese disaster shows that she doesn't understand the technology. Fukushima incident will impact any project (at least in PR sense) that has "nuclear" in it, no matter how different process is. Germany's actions (hey massive cunami caused problems in some reactors in Japan, let's shut down ours!) is a good example that rationality has little to do in such cases :(
- jeffreymcmanus 16y ago
  It must be a truism of hacker news that public relations appears to be the biggest impediment to what is likely the biggest scientific breakthrough of the next 10-20 years. The first team to reach net power out (and there are many teams around the world working on different paths to this at the moment) will have no trouble explaining it to people in a way that will differentiate it from dirty nuclear power. Getting to net power out will be, by far, the more challenging part.
  - hugh3 16y ago
    Actually, I think the National Ignition Facility will have no trouble in getting net power out, very soon. The real challenge is getting a significant amount of power out at some non-insane cost, since the NIF in its present form costs billions of dollars and can only do one fusion shot every couple of weeks. The NIF's plan for a commercial inertial confinement fusion reactor looks like the NIF, except that shots occur ten times a second. At the moment they have no way of firing the lasers that often, or of extracting all the energy thus produced.
    - Retric 16y ago
      Is NIF getting close to breakeven in terms of laser input energy, energy generating the lasers, or thermal energy to power a turbine to power the lasers? Because, useful power generation requires ~30-100x breakeven in terms of laser energy and last time I checked they where several orders of magnitude from that standpoint.
  - 16y ago
andrewcooke 16y ago
or your comment shows you don't understand politics?
- baggachipz 16y ago
  If a leader doesn't understand the difference between fusion and fission, that's another issue entirely. Not saying they do, by the way.
sliverstorm 16y ago
If a random blogger doesn't understand the difference, what are the odds a random Joe understands? The collective opinion of Joe is what constitutes public opinion, and public opinion is (as I understand it) one of the biggest obstacles.

cperciva 16y ago

Fusion != Fission, and in this case there isn't even any radioactive material in the equation Fusion reactors spew neutrons which can create a variety of radioactive isotopes. Most of these are very short-lived, fortunately -- but they do exist, and reactor designs need to take these into account. (Also, some reactor designs use tritium as fuel, which is of course radioactive to begin with.)

DennisP 16y ago
True but the other difference is that fission reactors have to be kept cool. With fusion reactors, the challenge is getting it hot enough. There's never a concern about loss of cooling, meltdown, all that mess. Also of course, several projects are attempting boron fusion, which doesn't produce neutrons other than from a small portion of side reactions.
- cperciva 16y ago
  Right, I agree that fusion reactors are inherently much safer than fission reactors -- I just wanted to make the point that they're still not completely harmless.
hugh3 16y ago
Related anecdote: I visited the National Ignition Facility [1] last year, where everything was pretty much up and running but they still hadn't finished putting in all the shielding that needs to surround the target chamber before they start actually doing fusion shots. We were assured that if they had done a fusion shot before installing the shielding then everyone in the (extremely large) building would have been dead due to (if I recall correctly) neutron absorption. Side note: the National Ignition Facility is freaking awesome. [1] http://en.wikipedia.org/wiki/National_Ignition_Facility http://en.wikipedia.org/wiki/National_Ignition_Facility
jeffreymcmanus 16y ago
It's worth mentioning here that coal-fired power plants also spew radioactivity into the atmosphere.
- lispm 16y ago
  Especially old coal power plants which have not upgraded with filters...
  - billswift 16y ago
    Actually, a large part of the radioactivity is in the form of C-14 in carbon dioxide which is unaffected by filters.
    - lispm 15y ago
      'Large part'? Numbers, please. C-14 is not much contained in old fossil fuels due to radioactive decay. The literature also discusses the Suess effect, which shows that coal power plant reduced the effect of C-14.

neutronicus 16y ago

That's not exactly true. There's enough neutron flux in a hypothetical fusion reactor (assuming D-T) for neutron activation of structural materials to be a real concern. There are actually some hybrid fission-fusion designs which use a fusion reactor running at a loss as a neutron source for a subcritical assembly of fission fuel. You're right that the fission products and high-mass-number alpha emitters have left the picture, though.

rimantas 16y ago

The author's assertion that this project will be impacted by the Japanese disaster shows that she doesn't understand the technology. Fukushima incident will impact any project (at least in PR sense) that has "nuclear" in it, no matter how different process is. Germany's actions (hey massive cunami caused problems in some reactors in Japan, let's shut down ours!) is a good example that rationality has little to do in such cases :(

jeffreymcmanus 16y ago
It must be a truism of hacker news that public relations appears to be the biggest impediment to what is likely the biggest scientific breakthrough of the next 10-20 years. The first team to reach net power out (and there are many teams around the world working on different paths to this at the moment) will have no trouble explaining it to people in a way that will differentiate it from dirty nuclear power. Getting to net power out will be, by far, the more challenging part.
- hugh3 16y ago
  Actually, I think the National Ignition Facility will have no trouble in getting net power out, very soon. The real challenge is getting a significant amount of power out at some non-insane cost, since the NIF in its present form costs billions of dollars and can only do one fusion shot every couple of weeks. The NIF's plan for a commercial inertial confinement fusion reactor looks like the NIF, except that shots occur ten times a second. At the moment they have no way of firing the lasers that often, or of extracting all the energy thus produced.
  - Retric 16y ago
    Is NIF getting close to breakeven in terms of laser input energy, energy generating the lasers, or thermal energy to power a turbine to power the lasers? Because, useful power generation requires ~30-100x breakeven in terms of laser energy and last time I checked they where several orders of magnitude from that standpoint.
- 16y ago

andrewcooke 16y ago

or your comment shows you don't understand politics?

baggachipz 16y ago
If a leader doesn't understand the difference between fusion and fission, that's another issue entirely. Not saying they do, by the way.

sliverstorm 16y ago

If a random blogger doesn't understand the difference, what are the odds a random Joe understands? The collective opinion of Joe is what constitutes public opinion, and public opinion is (as I understand it) one of the biggest obstacles.