A nuclear reactor decommissioning system according to an embodiment includes a cutting device to cut a reactor, a lifting device inserted inside the reactor to lift the reactor, and a shielding device that is positioned between the reactor and the lifting device and blocks radioactive dust generated by the cutting device from spreading.

Proposed is a passive condensation tank cooling system of a passive auxiliary feedwater system, the cooling system allowing a passive condensation tank to include an inner wall and an outer wall and a cooling means to be interposed between the inner wall and the outer wall, thereby suppressing the increase in the temperature of the heat exchange water in a condensation process in the passive condensation tank. To this end, proposed is the passive condensation tank cooling system of a passive auxiliary feedwater system, the cooling system including: a passive condensation tank having a water storage space to store heat-exchange water; and a condenser arranged to be immersed in the heat-exchange water in the passive condensation tank, wherein the passive condensation tank includes the outer and inner walls providing the water storage space and a cooling means interposed between the walls for absorbing heat of the heat-exchange water.

A method for decommissioning a heavy water reactor facility includes: opening an upper part of the calandria vault; inserting a support device into an inner part of the calandria vault through the upper part of the calandria vault to support the main shell of the calandria; cutting between the main shell and the sub-shell of the calandria by inserting a cutting device into the inner part of the calandria vault through the upper part of the calandria vault; and drawing out the main shell of the calandria to the outside of the calandria vault by moving the support device from the inner part of the calandria vault to the outside through the upper part.

A safety cover structure of a nuclear facility is disclosed. The safety cover structure of a nuclear facility includes: a cover portion rotatably provided over body protection concrete so as to cover a cavity in which a reactor pressure container is positioned; a driving part for providing rotational driving power to the cover part; an opening and closing portion provided at the cover portion and thus products from the cutting and dismantling of the reactor pressure contain move therethrough; a fire extinguishing portion for extinguishing a fire occurring inside the cover portion; a radiation sensor which is provided on the cover portion and which measures radiation dose; and an alarming portion, which receives a sensing signal of the radiation sensor so as to issue an alert when radiation greater than or equal to a predetermined value is discharged from the reactor pressure container.

A method for complex-decommissioning a nuclear facility is disclosed. The method for complex-decommissioning the nuclear facility includes: cutting and expanding an inner wall of the cavity; installing a cutting device that cuts and decommissions the nuclear reactor pressure vessel inside the cavity; fixing the nuclear reactor pressure vessel inside the cavity by using a fixture; and cutting and decommissioning the nuclear reactor pressure vessel fixed inside the cavity by using a cutting device.

A method for dismantling a steam generator or heat exchanger, such as found in nuclear power plants, which steam generator or heat exchanger includes a plurality of primary circuit tubes with a contaminated inner surface and wherein one or more tubes are sealed with a plug at both end is provided, the method comprising a) opening one or both ends of each sealed tube by creating an opening in or removing, the plug (13); b) introducing a viscous polymer to cure inside the tube wherein the polymer fills the tube across the full tube cross-section at least at the tube ends, immobilizing contaminations in the filled portion inside the tube (11); c) curing the polymer, then detaching the tubes with cured polymer the detached tubes being sealed by the polymer d) sorting out the detached tubes with polymer.

An underwater decommissioning method of a nuclear facility is disclosed. An underwater decommissioning method of a nuclear facility that includes a nuclear reactor pressure vessel and bio-protective concrete including a cavity in which the nuclear reactor pressure vessel is positioned, includes: (a) floating the nuclear reactor pressure vessel above the cavity; (b) forming an insertion part filled with water in a side spaced apart from the cavity, and installing a support part on a bottom surface of the insertion part; (c) mounting a lower portion of the nuclear reactor pressure vessel on the support part; and (d) repeatedly cutting and decommissioning the nuclear reactor pressure vessel mounted on the support part by using a cutting device in an underwater position.

A system for servicing a nuclear reactor module comprises a crane operable to attach to the nuclear reactor module, wherein the crane includes provisions for routing signals from one or more sensors of the nuclear reactor module to one or more sensor receivers.

A system for servicing a nuclear reactor module comprises a crane operable to attach to the nuclear reactor module, wherein the crane includes provisions for routing signals from one or more sensors of the nuclear reactor module to one or more sensor receivers.

A radioactive structure dismantling method of a heavy water reactor facility that includes a calandria including a main shell and a sub shell, a calandria vault that receives the calandria therein, and a cover assembly that covers the calandria according to an embodiment, includes: preparing dismantling of the calandria; dismantling a reactor pipe installed in the calandria; dismantling the cover assembly that covers the calandria; dismantling the calandria; and dismantling the calandria vault.