Abstract: A method for decommissioning a heavy water reactor facility includes: removing the plurality of guide tubes from a plurality of through-holes; installing a plurality of shielding stoppers in the plurality of through-holes; removing the shielding stopper installed in one through-hole of the plurality of through-holes, and inserting a cutting device into a lower portion of the reactivity mechanism deck through the one through-hole to cut a connection portion between the reactivity mechanism deck and the calandria vault by using the cutting device; and separating the reactivity mechanism deck from the calandria vault.

Abstract: The present invention relates to a power plant early warning device and method which employ a multiple prediction model, and includes: a plurality of prediction models which receive information about the operation states of equipment in a power plant, and output prediction values and the reliabilities of the prediction values; a reliability analysis module which quantizes and analyzes the reliabilities output from the plurality of prediction models to determine the ranks of the plurality of prediction models, and calculates a final prediction value; a comparison module which compares the final prediction value with an actual measurement value, and outputs a residual; and a determination module which analyzes the residual to determine whether there are defects in the operating states of the equipment in the power plant.

Abstract: Provided is a UV reaction apparatus for treating waste liquid caused by system decontamination in a nuclear power plant. The UV reaction apparatus comprises a UV irradiation unit for irradiating UV light as a bar-shaped body; and a transit unit accommodating the UV irradiation unit therein, and for passing organic waste liquid to be irradiated with the UV light, wherein the transit unit comprises, an input unit, into which the organic waste liquid is input a discharge unit, through which the organic waste liquid is discharged, and an intermediate unit located between the input unit and the discharge unit, and in which the UV irradiation unit is located.

Abstract: Provided is a device for monitoring degradation of wastewater from nuclear power plant decontamination. The device for monitoring degradation of wastewater from nuclear power plant decontamination comprises a UV reactor connected to a first flow path and for UV-treating introduced wastewater; a wastewater degradation flow path for supplying the wastewater discharged from the UV reactor to the first flow path; a wastewater degradation detecting unit for analyzing components of the wastewater supplied from the wastewater degradation flow path and detecting whether a set condition is satisfied; and a purification flow path for purifying and supplying the wastewater supplied from the UV reactor to the first flow path when the set condition is satisfied.

Abstract: The present invention relates to a transport basket for defective spent nuclear fuel of a heavy water reactor and, more particularly, to a transport basket for defective spent nuclear fuel of a heavy water reactor that can reduce the burden of a personnel when handling spent nuclear fuel in a test facility by minimizing a storage space and maximizing a thickness such that only a predetermined amount of spent nuclear fuel for soundness evaluation in the test facility can be transported.

Abstract: A device for measuring large-area radioactive surface contamination can simultaneously obtain a plurality of detection values. The measurement device includes a frame body having a plurality of holes; a mover that is connected to, and moves, the frame body; and a plurality of radiation detectors that rest in the plurality of holes. The detectors detect one or more of: alpha rays, beta rays, or gamma rays. The location and level of radioactive contamination are accurately identified according to a comparison of the detection values of the plurality of radiation detectors.

Abstract: Proposed is a cutting apparatus for a fuel basket accommodating spent nuclear fuel of a heavy water reactor, wherein the apparatus includes a base, a vertical support arranged on one side of the base; a turn table arranged to be reciprocated between one side and an opposite side of the base and be horizontally rotatable on the base; a horizontal support arranged to extend from an upper-end of the vertical support in a horizontal direction toward the turn table; a side-cutting means arranged on the vertical support protruding toward the turn table for cutting a side welding bead of the fuel basket mounted on the turn table; and an upper-cutting means arranged on the horizontal support protruding toward the turn table for cutting an upper welding bead of the fuel basket mounted on the turn table.

Abstract: 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.

Abstract: 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.

Abstract: The present invention relates to a device for tracking the basis of an abnormal state determination by using a neural network model, comprising: an abnormality type classification unit for classifying an abnormal state into a plurality of failures in an abnormal operation scenario in which a plurality of scenarios related to the abnormal state are stored; an operation variable deriving unit for deriving operation variables affecting an abnormal state determination result for each of the plurality of classified failures; a power plant operation variable weighting unit for weighting the variable related to the abnormal state from among the operation variables; and an abnormal state determination basis generation unit for tracking the basis of an abnormal state determination from the abnormal state determination result generated through the weighted power plant operation variable.

Abstract: 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.

Abstract: The present invention relates to a radioactivity measurement method and a radioactivity measurement system. A radioactivity measurement method according to the present invention comprises the steps of: measuring radioactivity while performing energy scanning and temporal scanning; preparing a database from a time-energy-related data set obtained in result of the scanning; and obtaining a radioactivity measurement value of desired time from the database.

Abstract: A device for separating a shielding slab for a heavy water reactor according to an embodiment includes: a body; a circular rail installed on at least one side of the body; and a decommissioner for decommissioning a shielding slab installed on the circular rail and installed on an inner wall of a heavy water reactor, wherein the decommissioner includes a decommission head moving on the circular rail, a separator installed in the decommission head and separating and desalinizing the shielding slab, and a gripper installed in the decommission head and gripping the separated shielding slab.

Abstract: 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.

Abstract: A nuclear reactor dismantlement system according to an embodiment includes bio-protective concrete including a first space into which a reactor is inserted and a second space that is connected to the first space and is expanded in the first space, a moving device that is positioned in the second space and moves the reactor, and a cutting device that is positioned in the second space and cuts the reactor.

Abstract: Proposed is a reactor cooling system for cooling down a reactor damaged by a disaster accident and a reactor cooling method using same using contaminated water generated at a nuclear reactor as a cooling water source for cooling the nuclear reactor after the accident, thereby maximally suppressing discharge of the contaminated water into the sea. To this end, the reactor cooling system prosed above includes a nuclear power generation facility, a seawater storage tank, a seawater inflow flow path for introducing the seawater into the seawater storage tank and a seawater discharge flow path for discharging the seawater from the seawater storage tank to the sea, connected to one end and another end of the seawater storage tank, respectively, a heat exchanger installed in a water storage space of the seawater storage tank, a contaminated water supply flow path, and a contaminated water discharge flow path.

Abstract: Disclosed is a method of producing Tc-99m by using nuclear resonance fluorescence. More specifically, and a method of preparing Tc-99m by using nuclear resonance fluorescence includes irradiating a ground-state Tc-99 nucleus with a photon beam, thereby causing a nuclear transmutation to proceed such that the nucleus excited to high energy and then undergoes a transition to Tc-99m.

Abstract: Proposed is a system for utilizing unused heat-exchange water of a passive auxiliary feedwater system, and a reactor cooling control method utilizing the unused heat-exchange water of the passive auxiliary feedwater system and, more specifically, a system for utilizing unused heat-exchange water of a passive auxiliary feedwater system, and a reactor cooling control method utilizing the unused heat-exchange water of the passive auxiliary feedwater system, which may allow the unused heat exchange water remaining after heat exchange in the passive condensation tank to be used as cooling water, thereby increasing the efficiency of reactor cooling and increasing the efficiency of initial response in an event of a reactor accident. To this end, the proposed system includes a passive condensation tank, a condenser, a steam supply line, and a condensate water recovery line and is characterized by that a residual water discharge flow path is arranged at the inside thereof.

Abstract: 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.

Abstract: An exemplary embodiment of the present invention provides an apparatus for dismantling for heavy water reactor facilities, including: a cutting device configured to divide a calandria of the heavy water reactor facilities into a main shell and a sub-shell; and a transfer device configured to draw the main shell cut by the cutting device to the outside, wherein the transfer device includes a fixing unit configured to fix the calandria; and a transfer unit configured to transfer the fixing unit.