| I spent several hours watching MIT's presentations about this reactor design. - The inner wall of the reactor is 3D-printed and replaced annually. This is easy because they've found they can make joints in the superconducting tape that add very little resistance, allowing them to include hinges letting them open the reactor. - Surrounding the inner wall is FLiBe molten salt. It's heated by the neutron radiation, acts as coolant for the thermal cycle, and as the breeding blanket (each high-energy neutron releasing two neutrons from impact with beryllium, providing plenty of neutrons for breeding tritium from lithium). Having a liquid blanket makes tritium harvesting easier. - Stronger magnetic fields damp down plasma instabilities, making containment easier. For years MIT has been running the Alcator C-Mod, which has more powerful fields than any other tokamak in the world, so they have some direct experience here. - The neutron-activated wastes would only need containment for several decades. (I don't know anything about the diverter, and I'm interested if you want to get into more detail.) The MIT folks argue that we understand tokamak plasmas much better than any other configuration, and have gotten far closer to breakeven than alternative designs, so that's where we should focus. However, there are some projects working on aneutronic fusion, mainly with p-B11. The biggest project is Tri Alpha, with $500M invested. They've achieved stable plasma at 10M degrees, and are about to start testing a new reactor which should reach 100M degrees. If the plasma continues working as the expect, they think it's a straightforward path to a production reactor; of course there could be surprises. Another approach is laser fusion with petawatt picosecond lasers. We're not far off from having a laser with the specs to attempt this, and these lasers improve by a factor of ten every three years. Helion, funded by YCombinator, is attempting a hybrid D-D/D-He3 reaction. (The output of D-D is half He3, and half tritium which decays to He3 with a 12-year half-life.) They say the hybrid reaction would release only 6% of its energy as neutron radiation. I don't know how it's going though. |