Can a reactor running under 70% max hull heat destroy chests? I just had a chest near a running reactor that vanished. It was within the 5x5 cube, but max hull heat was only 66%, and when it disappeared it was 61%... Unfortunately, that happened to be the chest holding all the water buckets. 
Unfortunately, I wasn't watching at the time, so I don't know the nature of its demise. Didn't think they were flammable (at least not in vanilla)...
Did the reactor explode? What kind of chest was it?
Wooden chests will probably burn and the Personal Safes would probably get destroyed in the explosion.
Well, as luck would have it, the chest input tube was connected to the bottom, and a transposer was sucking buckets out the side... I came down to check on it, and the tube was popping buckets out, and the transposer was grabbing them in mid-air... so the reactor survived. It had actually cooled down to 4k heat from the 9k operating temp.
It was a wooden chest... Given that you can normally bury them in lava, I didn't worry too much about their flammability...
In any case, moving it out of the 5x5 danger area.
it burn any wood\wool in 5cube and melt any stone\iron.
nothing will drop in process, due reactor coding (it remove block completely)
also it will burn chambers (with nice effects) and personal blocks.
Thats why i always put a detector block that detects if buckets are coming out of the reactor. That way iam near 100% sure the cooling system is working. Also i got multiple redstone lines running to the reactor to prevent losing 1 of them and jamming the whole system.
