...
>However, on some nodes I've used the move nodedata thinking that as
>primary pools were backed up to copy pools and data was no longer
>present in the primary the copy pool data would expire, but this has not
>been the case.
...

Jim - Copy storage pools are tenacious... which is to say that they really
      do their job.  In ADSM QuickFacts I have this synopsis of how to deal
with that, as suggested by other posters:

Copy Storage Pool, delete node data     You cannot directly delete a node's data
                                        from a copy storage pool; but you can
                                        circuitously effect it by using MOVe
                                        NODEdata to shift the node's data to
                                        separate tapes in the copy stgpool
                                        (temporarily changing the stgpool to
                                        COLlocate=Yes), and then doing DELete
                                        Volume on the newly written volumes.

  Richard Sims