[Pwrrm] industry SNM query

I'm seeking a short description of how you perform the SNM inventory in the SFP including any challenges you may need to grapple with. For example, at D. C. Cook:

Our procedure provides for a piece count done visually. This involves standing at the edge of the pool (with FME controls and a life vest - no railing is installed) with a powerful flashlight and looking into the racks. We check each rack location as empty or containing fuel or containing a non-fuel item (e.g., a trash can), and we then compare the actual configuration to SNM records. It's not unusual to have visual challenges near the SFP cooling discharge due to air entrainment in the flow.