[delt0r]

I think you underestimate just how much of a big deal it would be. Especially in a small device. Real Nobel prize level of big. Currently there is no method of extracting energy. Its in the science phase. You don’t bother with collecting anything but diagnostics.

[delt0r]

As i said before, it can be minimized to the point of being manageable. If we are talking 100s of DT shots for a year and total T inventory needs to be large (aka 1g or so) then its a licencing nightmare, and activation is a serious problem (assuming you get burns). But if its much smaller and you don’t need to do so many shots, it really shouldn’t be a problem, at least not a big one. The radioactivity from a single shot would decay quickly (hours or so) But do tend to be gammas. Again its manageable.

If what you wanted to do was show breakeven or even burn with DT, then such a program does not need 100s of shots. And if done…. well i don’t think your going to have problems with grants again. At least for a while.

[delt0r]

Please read what i said. What does * shielding materials* have to do with fuel?

A break even DT or even better a burn with DT produces a lot of neutrons, probably well over 1J worth. You need to deal with them in a way that doesn’t produce secondary gammas or activation as much as possible. Typically this is borated concrete. Boron has a large neutron cross section. Boron salts can be added to water and the hydrogen is effective at moderating the 14MeV neutrons so that they get absorbed in shorter distances. You can run the numbers and you can get most of the neutrons absorbed by the boron (or Li ). Thus mittigating activation problems.

[delt0r]

The radioactivity from neutron activation is overplayed a bit. Its quite manageable if you keep the shot count low. Even without careful materials choices. The real problem is the amount of shielding you need for the neutrons in the first place. Its really quite a bit if you expect +1J of neutrons in a shot. I have though that water tanks with borated water etc would be a good temporary way of dealing with neutrons. Added advantage of reducing activation since the Boron absorbs most of the neutrons.

[delt0r]

There is a serious issue with the way scientists get along with one another. Its quite obvious with the fusion “debate” when we discuss funding. The venom that some people push forth about the situation is particular destructive to diverse funding efforts, and even if everything they say is true, its the worst possible way to go about it. Learner is doing pretty dam well in that regard (at not begin venomous… but throwaway comments about ITER don’t help at all).

Bottom line scientists are really bad at politics. Even when their own funding is at stake. We see the same thing in AGW debate and man that is going to bite a lot of people in the arse when the dust settles.

What we don’t need is a “give our project money, cus *that* project is stupid”, or “they have all the funding because they stole it from us” and worst of all, “Their approach will never work, they know it and lie to steel all our funding so they can be rich scientists”. *EVEN* if these things are true (I don’t believe so), they cannot help the situation in any way. They only increase the reasons to cancel *all* research in this area.

The main reason i think even quite a lot of scientist don’t take fusion seriously is because the plasma/fusion community fight like teenagers.

[delt0r]

seriously? Are you in acidemia? Academic reasons is not the same as at at university. Stop letting every comment a lawyer makes that is *not* legal advice carry any weight.

For the record. I can get access and i am legally allowed to give people a copy for academic reasons in the country I am in.

pm me if required.

[delt0r]

So someone can pm you and you can pm them back? A lot of articles that my uni does not have i get this way.

[delt0r]

you are allowed to give out preprints for academic use only. At least every journal i have ever published in permits this. Some journals give you a special link to do so.

[delt0r]

I have read it. They verify exactly nothing. The only thing verified was “a closed cylinder that we can’t look in and are not permitted to measure energy flow into/out of properly can get warm/hot”.

In other news its turns out there is far more than one sucker born a minute.

[delt0r]

You really should not compare the two. They are different orders of accident. Fukushima is quite small and much more localized that Chernobyl by a massive margin.

[delt0r]

Graphene is already old in that we have had in the lab in very small samples for a few years. Its not quite as strong as carbon nano tubes however. Also its not stable in a flat configuration over on a small size. It will roll onto itself.

Its strength is very high, but as always bulk material strength is always much less than microscopic “bond” strength due to imperfections that cannot be avoided due to thermodynamic reasons. There is at least one paper that suggests that strong enough fibers for a space elevator with CNT will not be possible.

Also bear in mind that if you have something 1/2 enough strong for a space elevator, making pretty impressive rockets are quite easy.

[delt0r]

Oh yea. Right. But again that is not how these spallation source work. They shatter the nucleus.

[delt0r]

err no. Knocking out neutrons does not change the atomic number.

[delt0r]

Funding is more nuanced that a petition i am afraid. Sure it can’t hurt. But i doubt it will help. We (the scientists) are often our own worst enemies as well.

[delt0r]

When a mercury nuclei is hit with a 1GeV proton it more or less explodes. A neutron is not knocked out. But some of the fragments are neutrons and they travel a long way while the charged fragments don’t.

[Author]

Posts