Disposal concept for LILW in Korea: Characterization methodology and the disposal priority

Since 1977 the Korea Hydro and Nuclear Power Co. has generated about 67,000 drums (200 L) of low and intermediate level radioactive waste (LILW) and the drums are stored in the temporary storage facility at each reactor site. The accumulated dry active waste (DAW) amounts to around 36,600 drums. There are around 19,000 drums with evaporator bottoms, 9700 drums of spent resin, and 1600 drums of spent filters. This study proposes four mandatory items with regard to the radioactive characterization of LILW: namely, the total activity, surface dose, individual activity, and surface contamination. The required contents of the physical characterization include the weight (density), voidage, free liquid, and homogeneity. For the chemical characterization, the required contents include leachability, corrosiveness, explosiveness, and chelation. Finally, the compressive strength and integrity of drums are requested for the mechanical characterization. To determine the disposal priority of LILW in the Republic of Korea, the authors considered two main factors, namely, the waste management situation in Korea and overseas case studies. After considering those factors, the authors established a disposal priority for the LILW: (1) concentrated waste solidified with the cement and low radioactive DAW, the characterization of which can be readily identified in detail; (2) spent resin solidified with cement; (3) spent filters; (4) highly radioactive DAW, the characterization of which is well documented; and (5) waste that needs to be researched further, including spent resin in PE-HIC, evaporator bottoms and concentrated waste solidified with paraffin, and DAW that contains some harmful materials.