Apparatus and method for enlarging inner diameter of injector for reactor

A method of enlarging an injector of a reactor, comprising:

• securing a drill assembly to an exterior surface of the injector protruding through and extending from an exterior wall of the reactor, the drill assembly including:
• an elongated shaft;
• a piloted drill bit attached to an end of the elongated shaft and including a pilot portion distal from and extending colinearly with the elongated shaft and a cutting portion proximal the end of the elongated shaft and positioned between the pilot portion and the end of the elongated shaft, wherein the cutting portion includes at least one cutting edge extending radially from a center axis of rotation beyond an outer surface of the pilot portion;
• and
• a drive device mounted to an elongate member and adapted to rotate the elongated shaft about the axis of rotation;
• advancing the drive device along the elongate member and thereby inserting the pilot portion into the injector;
• and
• actuating the drive device to cut away a portion of an inner surface of the injector with the cutting portion as the drive device advances along the elongate member.