That does not make logical sense. For any given nuclear weapon that doesn't kill the entire planet there is a range from the epicenter where a bomb shelter is e

That does not make logical sense. For any given nuclear weapon that doesn't kill the entire planet there is a range from the epicenter where a bomb shelter is effective, regardless of weapon yield. Yes, the area where people are killed even if they are in a bomb shelter is larger, but the area where people are saved by a bomb shelter is larger as well.