i was thinking on how to make reactors produce more power and safely and it came to me if they where cooled with liquid nitrogen they could handle much more fuel rods than ones cooled by standard methods right now. seeing as liquid nitrogen is at a temp around or below -346F you could really reduce heat produce with just a few of these. but only way to get liquid nitrogen would be thru a mass fabricator (i don't know all the combinations to it so cant post a recipe for it). if this where to be add i think it would make a nice addition to the mod also it could be used for future machines as well. 
info on liquid nitrogen
Under normal atmospheric pressure, nitrogen can exist as a liquid between the temperatures of 63 K and 77.2 K
(-346°F and -320.44°F). Below 63 K, nitrogen freezes and becomes a solid. Above 77.2 K, nitrogen boils and becomes a gas.
Since it is obtained from the atmosphere, liquid nitrogen is inexpensive and is rarely refrigerated. It is kept in insulated containers called Dewars and is allowed to boil away. Since it is boiling, most of the liquid nitrogen used in laboratories and in cryogenics shows is at a temperature of 77.2 K.