The video you listed is the one I was referring to. I did not know that Arnie was taking a portion of that video to show one fuel assembly top. In the opening seconds of the entire video when the bubbles are coming up and blocking the image you can briefly see a regular pattern that could be the top of the fuel assemblies. To do so, you have to look around the bubbles, preferably to the top and left.
Starting at about second 25 do a series of stops and starts to capture stills of the video. Granted there is lots of debris blocking the image, but I can see some fairly consistent regularity to the patterns partially visible underneath the debris. I believe that to be the top of the fuel assemblies.
All of that debris is sitting on top of something flat down there. NOW, what I can not tell you is the state of the fuel rods that extend down from the assemblies tops. All I can see is a fleeting pattern that suggests the fuel assembly tops are down there under a dozen feet or more of water.