TL;DR
Furnaces that are powered using heat pipes instead of electricity.Why ?
There is a concept in science fiction of using the heat output by a nuclear fision/fusion plant as a direct energy source for furnaces, instead of using a fuel. This would provide a high-capacity, high-speed furnace at the very end of the game that further integrates nuclear reactors and their associated systems into the factory.This may have the added benefit of further incentivising players to try their hand at and master the complexities of nuclear reactors.