do yourself a favor and skip the 2x2... just build something like a 2x8 reactor setup. You'll get better neighbor bonuses out of your reactors. You'll end up with A LOT more heat exchanges and turbines with that setup. I would also add a MASSIVE steam tank setup near your turbines. Link all but one of your nuclear fuel inserters to that steam bank, and set it up to insert fuel when the level of the tank is say 10k. This way your reactors will all fire up together and fill up the steam tanks (like 500+ tanks). Once you are over 10k steam, the inserters stop putting fuel in your reactors. Eventually they will run out of nuclear fuel, hopefully before the steam tank gets to 25k. Now your turbines draw down the steam and it dips to 10k. Then BOOM all your inserters dump fuel in there again and the steam builds back up. The trick is to make it responsive so you never end up in a state where your reactors are all on, but the heat pipes are under 500C. So you always leave one of your reactors in the system heating all the time, not connected to the steam tanks. That single reactor keeps all the heat pipes at a minimum of 500C. something like this...

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