If you have 20 minutes, the video linked in the comments of the earlier HN post is quite informative, giving a much better technical explanation than the origin

If you have 20 minutes, the video linked in the comments of the earlier HN post is quite informative, giving a much better technical explanation than the original article: https://www.youtube.com/watch?v=7gtog_gOaGQ https://www.youtube.com/watch?v=7gtog_gOaGQ It is fascinating, for example, how a slight change in the packaging of the fuel (as sand-sized pellets coated with carbon) affects the safety/stability of the design, and how resonances in the cross section for neutron absorption come into play (they broaden at higher temperatures, dampening rather than enhancing the overall reaction speed, as temperatures rise).