Hi Pete,
Ok... but there are better ways to do this. I guess I would first question the requirement of making alpha-numeric keys in the first place. An IDENTITY column would do especially since the natural key needs a modification of adding year and a sequence number to be unique.
And, I probably wouldn't use a While loop even though it'll probably be "good enough" for this case.
--Jeff Moden
Change is inevitable... Change for the better is not.