Recently, Japan’s government has announced Tokyo Electric Power Company’s plan to discharge contaminated water stored from the tanks of the Fukushima Daiichi nuclear power plant site into the sea. The contaminated water is treated by advanced liquid processing system (ALPS) to remove 62 radionuclide containing cesium, strontium, iodine and etc. using co-precipitation (or precipitation) and adsorption for other nuclides (except for tritium and carbon-14). The total amount of the contaminated water generated by ALPS facility is 1,311,736 m3 (as of August 18, 2022). The amount of contaminated water is estimated same as Tokyo dome volume. Under the sea discharge plan, the contaminated water will be diluted in seawater more than 100 times, and tritium concentration lowered 1/7 of the drinking water standard set by the World Health Organization (10,000 Bq/liters). The diluted water will then move through an undersea tunnel and be discharged about 1 kilometer off the coast.

• Sunghoon Hong(Korea Hydro and Nuclear Power (KHNP) Central Research Institute (KHNP-CRI)) Corresponding author
• Seok-Ju Hwang(Korea Hydro and Nuclear Power (KHNP) Central Research Institute (KHNP-CRI))
• Cheon-Woo Kim(Korea Hydro and Nuclear Power (KHNP) Central Research Institute (KHNP-CRI))