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The nice thing about fusion neutrons is you get to control the isotopes, you have no control over fission waste isotopes. Some fission isotopes are really icky
by VLM 10y ago
The nice thing about fusion neutrons is you get to control the isotopes, you have no control over fission waste isotopes.
Some fission isotopes are really icky to deal with, as everyone has heard...
On the other hand if you don't like dealing with cobalt-60 waste at your fusion plant, simply stop using cobalt alloys in your reactor vessel.
It turns out to be "not that big of a deal" to design a fusion plant where neutron activation isn't important. The quotes are because nothing is easy in fusion but as a problem its pretty low on the list.
- FiatLuxDave 10y agoThis is true. Back at Fiat Lux when we designed our D-D reactor, we intended it to sit inside a pool of water and borax. Since we didn't need to regenerate tritium, just absorbing the neutrons with boron was the cheapest solution. As far as I know, Borax is the cheapest effective neutron shielding known. We would have liked to have built our vacuum chamber out of purely Al (since Al-28 has a two-minute half-life), but we went with steel for cost reasons. Unfortunately, we never made enough neutrons to activate anything worthwhile. Nevertheless, it is certainly possible to work around neutrons through design decisions.
- erikgrinaker 10y agoSure, activation in itself isn't necessarily a big problem, but I believe that embrittlement of the blanket and other plasma-facing surfaces due to the high neutron fluxes is one of the major engineering challenges for ITER and similar tokamak designs.