(maybe a bug?)
running latest version on experimental
The nuclear heaters accept nuclear waste as an input, and return to you 10x what was put in.
Just for giggles I put in 10 nuclear waste barrels, and immediately the machine spat out 100 barrels of waste, with no effect. Nudge for purex? 
just curious: is it normal that the heaters produce 10 barrels of waste (at full heat) per nuclear fuel rod consumed?