In reply to Robin's message of Mon, 20 Mar 2023 07:10:35 +1100: Hi, PS - another possibility is that a simple elastic collision of a daughter product with a D passes sufficient kinetic energy to the D such that the D itself can split another D, or even multiple D's , thus creating more free neutrons. This may be an even more likely route, since during a simple elastic two body collision between a daughter nucleus and a D nucleus, the D will end up with most of the energy. The mass of the energetic D is low enough to markedly increase the chances a spalling during a following collision with another D (or possibly even a fusion reaction).
In short, there are multiple possible pathways that could lead to additional neutrons, so I think a small test reactor should be built. Salt solution reactors have been run in the past, but not using heavy water as moderator AFAIK. Cloud storage:- Unsafe, Slow, Expensive ...pick any three.
