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: 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: A waste liquid treatment apparatus with enhanced treatment capacity for a pre-treatment facility of a liquid radwaste treatment system for a nuclear power plant. The waste liquid treatment apparatus includes: a water tank into which a waste liquid is introduced and from which filtered permeated water is discharged; a waste liquid introduction section through which waste liquid is introduced into the water tank; submerged membranes annularly disposed and spaced apart from each other for filtering foreign substances from the waste liquid; a permeated water suctioning section suctioning the filtered water of the waste liquid and discharging the filtered water outside the water tank; an air supplying section supplying compressed air to the submerged membranes to remove foreign substances; and a porous support plate supporting the submerged membranes.

Abstract: A waste liquid treatment apparatus with enhanced treatment capacity for a pre-treatment facility of a liquid radwaste treatment system for a nuclear power plant. The waste liquid treatment apparatus includes: a water tank into which a waste liquid is introduced and from which filtered permeated water is discharged; a waste liquid introduction section through which waste liquid is introduced into the water tank; submerged membranes annularly disposed and spaced apart from each other for filtering foreign substances from the waste liquid; a permeated water suctioning section suctioning the filtered water of the waste liquid and discharging the filtered water outside the water tank; an air supplying section supplying compressed air to the submerged membranes to remove foreign substances; and a porous support plate supporting the submerged membranes.