Abstract: A nuclear reactor vessel has a nozzle plug in its cold leg and hot leg nozzles for isolating the reactor vessel from the balance of the reactor coolant loop. The nozzle plug is mechanically compression fitted with the nozzle without the need for hydraulic or pneumatic actuation. The plug has a primary seal ring compressed against the inner wall of the nozzle and a secondary seal ring compressed against the end wall of the nozzle for withstanding a pressure differential of about 34 feet of water.

Abstract: A nuclear reactor having a chemical decontamination system is provided in which every piece of decontamination equipment which processes radioactive materials is located within the containment chamber of the nuclear reactor. This decontamination system therefore presents advantageous safety benefits over an outside of containment system in the unlikely event of a leak of radioactive materials from the decontamination system.

Abstract: An internal tube cutter for cutting the inside of tubes of a nuclear steam generator comprises an extendable cutter capable of being disposed within a tube of a steam generator along with a flexible transverse positioning mechanism disposed on the cutter for positioning the cutter within the tube. The cutter is attached to a drive mechanism that is capable of rotating the cutter when the cutter is in an extended position to thereby cut the inside of the tube. The cutter and flexible transverse positioning mechanism are capable of being inserted into and traversing through tubes whose inside diameter is severely reduced due to denting while being capable of being extended and severing the tube at a section of the tube having a normal diameter.