Remove the old reactors >:D
Perhaps, since the reactors are much more like irl nuclear boilers, a Pressure valve (Which displays EU/t and Heat level, instead of in the main GUI) could be added somewhere on the outside. There should also be a high tensile strength (Just a bunch of iron plating) frame for the reactor, since the lead is only needed as a radiation shield and doesn't make for very good structural support (Since you need a strong edge if you are going to have a square boiler). Perhaps later a "Reactor alarm" could be added which lets of a nice loud siren to tell you your reactor is about to explode ;D
Unrelated, but does each fluid port only let in/out a certain amount of fluid per tick or is it infinite?