Theese are NOT viking runes. They are an older Rune alphabet, from around year 500 and earlier. They are called the elder futhark. The viking Rune alphabets have usually only 16 runes and there are several different alphabets from that time.
A Celtic shield signifies bravery and strength. I like the aspect of a warrior in this symbol. I want to get a Celtic cross with some kind of boarder around it. maybe this to show strength of faith. I really like that idea and I love this pattern.