3 ms·
What's wrong with pulling the energy from the magnetic containment system? We already are using the magnetic containment system to redirect charged particles i
by IX-103 4y ago
What's wrong with pulling the energy from the magnetic containment system?
We already are using the magnetic containment system to redirect charged particles in the plasma back into the plasma. If we do so less forcefully than they were heading out, but still enough to stop them from leaving, we can convert particle velocity directly into electricity (AC with a relatively linearly decreasing frequency distribution, I think). This also has the effect of cooling the plasma (since temperature is related to average particle velocity).
The challenges I see here are:
1) The faster the control system, the more efficient it is at extracting energy -- it can extract the energy of higher frequency components.
2) You may need a very large magnetic field (larger than needed for containment) to make this practical
3) Coil geometry and efficiency becomes critical.
- pfdietz 4y ago80% of the fusion energy from DT fusion comes out in fast neutrons, which ignore magnetic fields. The other 20% has to come out somewhere. If it could be converted to electrical energy maybe it could avoid surfaces (Helion plans to do this, with DD + D3He) but when it's just 20% of the output that doesn't buy you much.
- vintermann 4y agoI knew neutrons was a headache with nuclear energy in general, but I didn't know it was that bad. I would not be excited about attacking the problem of how to safely get energy out of a soup of hot, corrosive, exotic radionuclides.
- pfdietz 4y agoAnd DT fusion neutrons are even worse than fission neutrons, since they are much more energetic (and because only 3% of the energy in a fission reactor is released in neutrons.) The 14 MeV DT neutrons are above the threshold for (n,p) and (n,alpha) reactions, which cause gas to accumulate in reactor materials. The helium produced by (n,alpha) reactions accumulates in tiny bubbles that would reach extreme pressures and rip materials apart.
- jjk166 4y agoAnd neutrons pass straight through solid matter, dumping their energy volumetrically, completely solving the surface area scaling problem.
- pfdietz 4y agoWell, no, not completely solving it. There are limits to neutron fluence materials will withstand. Even neutron heating can't be too nonuniform in the blanket.