<10% on Nostr: At the most basic they need to have closed loop cooling so that any pollutants stay ...

At the most basic they need to have closed loop cooling so that any pollutants stay within the plant and are not discharged to the environment. This means that although the waste heat is discharged (a problem in itself) the water that takes the heat away is not otherwise impacted. Secondly, if they have renewable power source then the waste heat is not greater than has been removed from the environment to generate that power.