A321
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical
Flight Crew Returned To Gate; General Maintenance Action
Aircraft
After pushback and engine start (both engines stabilized) and after both pilots accomplished their respective after start flows; I called 'Flaps 2 taxi.'  As the airplane began to move; maybe 15 feet straight ahead; the number 2 engine failed.  Passengers noticed a 'large puff of blue smoke.'  I stopped and assessed the situation; ATC and surrounding aircraft saw no flames or smoke.  I asked my First Officer to request a return to the gate. While he was doing that I made a public address to the passengers of the situation and we returned to the gate.  Maintenance Foreman thought possibly a FADEC or maybe even a severed fuel line.  I made no attempt to restart the number 2 engine with this the possibility of 'raw fuel' in the tailpipe area or burner as it could ignite a tailpipe fire or worse.
A321 Captain experiences a number two engine failure (flame out) as he is beginning his taxi away from the gate.  Aircraft is returned to the gate for maintenance