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MIT's ARC design solves neutron flux by making the inner core of the reactor easily replaceable. The superconducting coils are hinged, so once a year they can j

MIT's ARC design solves neutron flux by making the inner core of the reactor easily replaceable. The superconducting coils are hinged, so once a year they can just open up the reactor and lift out the core, which is 3D-printed. The core is surrounded by molten FLiBe salt, which functions as coolant and tritium breeder. The new superconductors allow the reactor to be much smaller than ITER for the same power output. MIT's project has been spun off into the startup Commonwealth Fusion Systems, which has investment from an Italian oil company and Breakthrough Energy Ventures. Neither party has an interest in physicist job creation or weapons work. There are at several pB efforts and one D-D/D-He3 (Helion, which says only 6% of energy would be released as neutrons) but it's harder to get net power from aneutronic fusion and we don't understand the plasma physics as well for the designs they need, so it's more of a wildcard at the moment.

ncmncm 8y ago
Thank you, this is informative. I will say here that I have no knowledge that pB aneutronic fusion can be made to work, but whether it can has no bearing on whether tokamak generators will ever go on line.
pfdietz 8y ago
MIT's ARC design has an estimated cost of $29/W(e), an order of magnitude higher than PV. Each 170 MW(e) ARC reactor will use 40% of the world's annual production of beryllium. The "easily replaceable" in your description is quite a stretch. The replacement will be much more demanding than the replacement of fuel elements in a fission reactor. In the latter, the radioactivity is almost entirely contained inside the fuel elements, and they are simply transfered, as fuel bundles, to a cooling pool. But the 86 tonne reactor vessel in ARC will have been permeated with tritium, and the tungsten will have been loaded with activation products by the intense neutron bombardment. It will be much larger than the rather compact arrangement of fuel rods that makes up a PWR core (about 165 tonnes of fuel, including structural material, in a typical 1000 MW(e) power reactor, which has nearly six times the power output of the ARC design.) The reactor vessel will take more space to remove. And then it will have to be crushed. The workspace in which this happens will become inaccessible to people, as it will become contaminated with tritium and radioactive tungsten dust. The overall volume inside the reactor building where all this happens will be very large, making the building expensive.

ncmncm 8y ago

Thank you, this is informative. I will say here that I have no knowledge that pB aneutronic fusion can be made to work, but whether it can has no bearing on whether tokamak generators will ever go on line.

pfdietz 8y ago

MIT's ARC design has an estimated cost of $29/W(e), an order of magnitude higher than PV. Each 170 MW(e) ARC reactor will use 40% of the world's annual production of beryllium. The "easily replaceable" in your description is quite a stretch. The replacement will be much more demanding than the replacement of fuel elements in a fission reactor. In the latter, the radioactivity is almost entirely contained inside the fuel elements, and they are simply transfered, as fuel bundles, to a cooling pool. But the 86 tonne reactor vessel in ARC will have been permeated with tritium, and the tungsten will have been loaded with activation products by the intense neutron bombardment. It will be much larger than the rather compact arrangement of fuel rods that makes up a PWR core (about 165 tonnes of fuel, including structural material, in a typical 1000 MW(e) power reactor, which has nearly six times the power output of the ARC design.) The reactor vessel will take more space to remove. And then it will have to be crushed. The workspace in which this happens will become inaccessible to people, as it will become contaminated with tritium and radioactive tungsten dust. The overall volume inside the reactor building where all this happens will be very large, making the building expensive.