The aircraft isn't going to be "grounded".
Mad Scientist
I concur with your analysis.
Since entry into service the A330/A340 (same design / two A/C) fleet has accumulated :
- over 27 700 000 flight hours,
- in over 5 200 000 take-offs.
As the AF447 accident is the first one (one too much of course) with no obvious root cause, I do not see how any Airworthiness Authority could mandate a grounding of the fleet.