3 ms·

As I understand the neutrons of the D+D->He3+n reaction are slow neutrons (2.45MeV) that won't damage too much the materials. These are not the fast neutrons o

• DennisP 4y ago
  6% as neutron radiation is the figure I've seen, from Helion and other sources. According to the head of MIT's fusion department, even D-T neutrons only mean you'll have to bury the activated materials for a few decades. A much lower amount of lower-energy neutrons isn't going to cause any major problems.
  • 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