That's indeed the case, but it also avoids the neutron embrittlement of the reactor building, it avoids a lot of the costly maintenances associated with it (replace strut X every 1.5 years of operation), and said maintenances would also have been complicated by having to operate in a building which is now itself radioactive due to neutron activation.
The beauty of pB11 is that it just produces (mostly) helium, so it doesn't make the place radioactive. A very small amount of reactions result in short lived C11 (20 minutes half life) and the occasional neutron, but nowhere near the amount of DT (1 neutron per reaction).
No proliferation potential, no waste disposal problem, no dangerous fuel also lead to greatly reduced security costs. And very little decommissioning costs.
It will still produce neutrons via the (alpha,n) reaction on 11B. And it will produce very energetic gammas by the (p,gamma) reaction. These gammas are energetic enough to cause photonuclear reactions in the surrounding materials, including production of photoneutrons.
While the amount of neutrons would be so low that materials could handle them, they'd still make the reactor hot enough that hands-on maintenance would not be possible (it would make it easier on remotely operated repair machines, though.)
It's a shame none of the p-11B schemes appear to be workable. Helion's approach seems more realistic (if still a stretch) and would also greatly ease neutron levels, if not to the same extent p-11B would.
I was under the impression that the neutron flux would be very low, and those neutrons would not be likely to activate any material due to their energy - I stand corrected, thank you.
Yes, the neutron flux would be very low. But it doesn't take much activation to exceed the limit for hands-on maintenance of the innermost part of the reactor.
https://www.hsfk.de/fileadmin/HSFK/hsfk_downloads/Strong_Neu...