Abstract: A device for sealing a penetration in a pressurizer of a nuclear steam supply system includes a hollow cylinder adapted to be inserted into the heater sleeve, in place of the heater. The cylinder includes a nose portion formed with a number of axially extending slots defining therein a number of radially displaceable segments, each of which has an outwardly extending flange, proximate its distal end, which is engageable with the heater sleeve to resist blowout. A rod, inserted into the cylinder, seals the passage therethrough while locking the displaceable nose portion segments in their sleeve-engaging position. An annular soft nickel band on the outside of the cylinder engages the inner surface of the heater sleeve to provide an effective seal therebetween.

Abstract: In combination, a vessel (10), opening means (16) in the vessel, a cover (18), flange means (20) surrounding the opening means, a primary closing means (22, 24) for the cover including a plurality of studs (22) securing the cover onto the vessel, the studs having inner ends threaded into openings (26) in the vessel, nuts (24) cooperating with the outer ends of each of the studs, secondary closing means (32, 34, 38, 40) for the cover including cylindrical clamp means (30, 32) made up of more than one piece, a protruding ledge (34) on the cover over which the clamp means extends, an annular groove (36) in the flange means into which the clamp means extends, a circular retaining ring (38) which surrounds the clamp means, a plurality of threaded openings (42) in the retaining ring, and a plurality of set screws (40) threaded into the openings, so that their ends force the clamp means into tight clamping engagement with the ledge on the cover and the groove in the flange means.

Abstract: A continuous belt traverses a river through channels on the river bed and carries intercepted material to the river banks for separation of precious metals and gemstones therefrom. Method and apparatus claimed.