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Exactly, the neutron induced radioactivity is orders of magnitude lower than in fission by-products and is a minor issue. The problem is more with neutron embr
by joak 4y ago
Exactly, the neutron induced radioactivity is orders of magnitude lower than in fission by-products and is a minor issue.
The problem is more with neutron embrittlement that weakens the materials exposed to fast neutron radiations. For DT fusion in tokamaks the idea is to replace the inner core every year or so.
Helion claim embrittlement is not much an issue for them. First, because their neutrons are relatively slower and second, because they can choose neutron resistant materials since they do not fear plasma contamination thanks to the pulsed nature of their operation: in between pulses they vacuum the vessel before injecting the exact mix needed.
In tokamaks, the materials facing the plasma are designed primarily to avoid emissions that might contaminate the plasma, embrittlement comes as an afterthought. Also in DT fusion, it's not 6-10% of the energy released as slow neutrons, but 100% as fast neutrons.
Conclusion: there is a neutron problem but it seem minor and fairly solvable