In the vanilla game, heat exchangers and steam turbines aren't the easiest thing to set up if you want round numbers; the heat exchanger consumes slightly more than 100 units of water per second, and the steam turbines consume more than half of one exchanger's worth of steam.
This mod just changes the temperature of the steam produced so that the water consumption is exactly 100/s, and so that one exchanger can supply exactly 2 turbines. And of course, the amount of power produced was kept at 10MW per exchanger, so now nuclear setups can become much more orderly!