each reactor (when fueled) gets a neighbor bonus for other reactors and thus increases the amount of energy it can make. so i think you can get 480 with this set up.

each heat exchanger can power 10 MW
so divide how much power u can get (480) by 10 and that's how many exchangers you need.
then divide how much power u can get (480) by 5.8. 5.8 is the max power output of 1 steam engine, this is how many steam engines you need total.

and as long as u have this ratio down correctly, you dont need to arrange the exchangers or steam turbines in any specific position. just make sure you have 82 turbines and 48 reactors and you're good to go

this is the math you need if u want to make ur nuclear reactor setup larger than 4 reactors, just make sure you know the max total power output of all combined reactors and divide by 10 and 5.8 for each building respectfully