PRI administers the Nadcap audit program for various special processes such as Heat Treat, Chemical processing (anodizing and such), Non Destructive testing and others.
Here is the link to the web site
PRI who administers the program offers training on some technical aspects of the audit process and the various task groups for each of the individual special process also give training on preparation for the audit covering typical findings seen and how to prepare.
There are also quarterly meetings held in various locations around the world where the programs are discussed in person with the representatives of PRI, the Primes and those who have to go thru the audits.
If you need additional detail info let me know and I would be glad to try and answer your questions.