Burrell, 32, said racism is "rife" in the sport, with racist "banter" becoming "normalised" among team-mates.
Falcons had already launched their own internal investigation to determine whether the racism he experienced happened while at the Premiership club.
However, the club says it will now be conducted by the RFU.
Ex-England centre Burrell was released by the Falcons in June after two seasons.
