To ensure its safe discharge into the environment, liquid radioactive waste has to fulfill very strict requirements connected with the limits of radioac­tive substances and other impurities (suspended particulates, chemical, bio­logical, heavy metals, etc.). To achieve the standards described in national

regulations, radioactive waste has to be treated, including volume reduction and reduction of radioactive compounds and other solutes in the effluent.

NPPs currently in operation in Korea have their own gaseous, liquid, and solid waste treatment facility and on-site storage facilities to ensure the safe management of RAW generated in the process of operation. The gaseous waste treatment system comprises gas decay tanks and/or charcoal delay beds. The liquid waste treatment system is equipped with either liquid waste evaporators or selective ion exchangers. The solid waste treatment facility has spent resin drying systems, spent filter processing and packaging systems, concentrated waste drying systems, and dry waste compactors. The RI waste generated from domestic medical research, industrial RI users, and research institutes is collected and stored at the Central Research Institute (CRI) of KHNP in Daejeon. Around 90% of LILW comes from NPP and the rest arises from industry, medicine, and research institutes.

Generally, the type of LILW is classified as follows:

• power plants: dry active waste, spent resin, spent filter, and concentrated waste

• non-power plant sources (RI waste): dry active waste (combustible or non-combustible), hepatitis waste, organic liquid waste, spent sealed source, spent resin, spent filters, and concentrated waste.

Figure 21.3 summarizes the process steps for treatment of solid, liquid and

gaseous wastes in Korea.