It's high in the sky and can demolish maybe about a 50 block radius depending on the setting; more delay on the line of repeaters makse the radius larger, and less delay makes the radius smaller. The download has it set to 1 tick below the maximum delay just in case.

MCEdit Schematic: http://www.mediafire.com/download/sbthdhnfhtr1n7l/Stinkinglamb_44's_nuke_dispenser.schematic
(the integrated uploader didn't work for me)