If this is a large diameter, nearly atmospheric, vessel, you shouldn't even model nodes 50, 60, or 61, but instead use the "nozzle flex" calculations.

Pressure vessel modeling techniques are invalid for thin-walled vessels.

You also need to ensure that your piping is sufficiently flexible to allow the tank to move the pipe, and not the other way around.

Your tank settlement needs to be factored into the displacements calculated in the nozzle flex, and you should also pay special attention to whether settlement occurs every time the tank fills or if it's a one-time operation.