this is the big reactor im working on atm
http://br.sidoh.org/#reactor-design?length=25&width=25&height=4&activelyCooled=false&controlRodInsertion=0&layout=160O5C20O5C20O5C20O5C16O4C5X4C12O4CXCXCX4C12O4C5X4C12O4CXCXCX4C12O4C5X4C16O5C20O5C20O5C20O5C160O
my question is do i need to fill all of...