The Kairos Reactor is a pyramid-agglomerate of, typically, graphite-HEU but also MOX balls made to plutogenize and produce energy altogether under a very high thermal stream (HTGR). The students in Kairos Uni seem to have made an experiment with nitrates from agricultural waste (inspired by Lukashenko’s “biotech” plant) altogether with sodium, based on the Kairos HTGR model. It… exploded.

From @_AstroErika

Some might argue that China fired a combinated missile. Indeed China actually fired a combinated missile (well done, without a human corpse in the reactor) onto New Zealand a few days ago and it was seen as “meteor”. I can see through the particular shape of the “fireball” the precise pattern of the combinated missile and can confirm you that China fired a missile there and that it burned in the descent phase because there was enough oxygen in the atmosphere, so that the stato part was saturated (the availability of oxygen is related to a lot of thermal energy production emitting CO2 (and volcanoes also emitting CO2, in addition to fossil fuels) and a lot of healthy vegetation altogether producing frequently O2 from that CO2… so the missile goes “chalumeau” in descent phase). It remains that sodium in any nuclear core is extremely explosive and hard to control. Especially within a reactor, like the HTGR. But this shape of the explosion is weird :

Based on all this, I tend to think that a Chinese missile was actually fired on that area and that because of the limited vegetation (that is among other things a result of past nuclear research activities, the area around the Idaho National Lab facility is pretty much a desert for instance because of the EBR facility accident) and high costs of gasoline right now it suceeded in getting through, hitting that Kairos experimental reactor.