A dismantling and decontamination system of biodegradable concrete of a nuclear power plant according to an exemplary embodiment includes: a dismantling device for dismantling an in-core instrument installed under biodegradable concrete to form a lower penetrated part of the biodegradable concrete; a decontamination device inserted inside the biodegradable concrete for decontaminating radioactive waste of the inner wall of the biodegradable concrete; a waste receiving device movable through the lower penetrated part of the biodegradable concrete; and a blocking device for blocking the upper opening of the biodegradable concrete to block an outflow of the radioactive dust.

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.

A decommissioning method of biodegradable concrete of a nuclear power plant according to an exemplary embodiment includes: decommissioning a neutron detector positioning device installed to biodegradable concrete surrounding a nuclear reactor to form a plurality of penetrated parts in the biodegradable concrete; inserting a part of a cutting device into the plurality of penetrated parts; and decomposing the biodegradable concrete into a plurality of sub-concrete parts by using the cutting device.

A method for decommissioning a nuclear facility includes: separating a nuclear reactor pressure vessel from biodegradable concrete; decommissioning a concrete structure; covering the biodegradable concrete; and decommissioning the biodegradable concrete.

A method of decommissioning a nuclear facility, including: exposing the plurality of upper penetration holes by removing the plurality of sandboxes; enlarging an upper space of the cavity by cutting an upper portion of the biological shield concrete that is disposed between the plurality of upper penetration holes and between the plurality of upper penetration holes and the cavity; and separating the nuclear reactor pressure vessel from the biological shield concrete.

A method of decommissioning a nuclear facility including a plurality of sandboxes that cover a plurality of upper penetration holes, includes: exposing the plurality of pipes through the plurality of upper penetration holes by removing the plurality of sandboxes; and cutting the plurality of pipes through the plurality of upper penetration holes.

Disclosed herein is a machine for cutting nozzles of reactor vessels. The machine for cutting nozzles of reactor vessels comprises a cutting unit positioned at an upper surface edge of a reactor vessel having a nozzle and having a saw blade part having different contact areas to cut the nozzle, a drive unit providing the saw blade part with rotary power, and a foreign substance suction unit provided at one end of the cutting unit in contiguity with the saw blade part to suck foreign substances generated when the nozzle is cut by the saw blade part, wherein the foreign substance suction unit sucks the foreign substances by approaching an outer peripheral surface of the nozzle when the saw blade part moves in a cutting direction of the nozzle.

Arc saw blades and systems and methods for segmenting components utilizing improved arc saw blades.

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.

An underwater decommissioning method of a nuclear facility including a nuclear reactor pressure vessel and bio-protective concrete comprising a cavity in which the nuclear reactor pressure vessel is positioned is disclosed. The method includes: (a) lifting the nuclear reactor pressure vessel above the cavity; (b) forming an insertion part in the bio-protective concrete adjacent to the cavity, filling the insertion part with water, and installing a support part on a bottom surface of the insertion part; (c) inserting the nuclear reactor pressure vessel in the insertion part and mounting a lower portion of the nuclear reactor pressure vessel on the support part; and (d) repeatedly cutting portions of the nuclear reactor pressure vessel mounted on the support part by using a cutting device in an underwater position. The method allows performing cutting operations in the water, and thus, it is possible to prevent radiation exposure due to occurrence of dust.