Abstract: An enclosed cutting zone for use in a nuclear power plant. The cutting zone includes a cutting zone barrier and a transfer zone. The cutting zone includes a movable submergible upper rig, an upper inflatable ring supported by the submergible rig; a lower inflatable ring supported by the submergible rig; and a means for coupling the vertically extending edges of the submergible upper rig to form a cutting zone barrier having enclosed sidewalls. The transfer zone includes a movable, submergible upper rig; an upper inflatable ring supported by the submergible rig; and a lower inflatable ring supported by the submergible rig. The transfer zone is coupled to exterior surface of the cutting barrier so as to form a structure having enclosed sidewalls and an open top.

Abstract: An improved surface traversing apparatus is provided in which one anchor or group of anchors is connected with one base, another anchor or group of anchors is connected with another base, each anchor group is movable en bloc transversely of its respective base for lateral movement across the surface of a member to be traversed, and the two bases are movable relative to one another in a direction which moves one finger group alternately toward and away from engagement with a member engaged by the other finger group. The anchors may be selectively expandable fingers which are longitudinally insertable into and retractable from openings in a steam generator tube sheet to provide the engagement therewith.