On March 11 2011, Fukushima Daiichi nuclear power plant site was attacked by a huge tsunami caused by Tohoku Pacific Ocean earthquake. Nuclear fuels of unit 1, 2, and 3 of Fukushima Daiichi nuclear power plant was melted down by the disaster. After the accident, Japan’s government has announced “Mid-and-Long-Term Roadmap towards the decommissioning of TEPCO’s Fukushima Daiichi Nuclear Power Station Units 1-4”. The topics of roadmap is made of measures to deal with contaminated water, removal of fuel rod assemblies from spent fuel pools, retrieval of fuel debris, measures to deal with waste materials, and other operations. To support the activity of the roadmap, various facilities about decommissioning have been established and operated on inside or outside of Fukushima Daiichi nuclear power plant site. Representatively, Collaborative Laboratories for Advanced Decommissioning Science which conducts R&D decommissioning, Naraha Remote Technology Development Center which develops remotes robots and VR (Virtual reality), Okuma Analysis and Research Center which performs radiochemical analyses for radioactive waste, and Fukushima Environmental Safety Center which conducts environmental dynamics and radiation monitoring.

The Fukushima nuclear power plant accident, which was caused by the Great East Japan Earthquake on March 11, 2011, is of great concern to the Korean people. The scope of interest is wide and diverse, from the nuclear accident itself and the damage situation, to the current situation in Fukushima Prefecture and Japan, and to the safety of Japanese agricultural and fishery products. Concerns about nuclear safety following the Fukushima nuclear accident have a significant impact on neighboring nation’s energy policy. It has been 11 years since the Fukushima nuclear accident. In neighboring nation society, the nature and extent of damage caused by the Fukushima nuclear accident, the feasibility of follow-up measures at home and abroad, the impact on neighboring nations, and the direction of nuclear policy reflecting the lessons of the accident are hotly debated topics. Recently, the controversy has grown further as it is intertwined with Japan’s concerns about the safety and discharge of the contaminated water into the sea, and conflicts over domestic nuclear power policies. About 1.29 million tons, as of March 24, 2022, of the contaminated water are generated, which is close to the 1.37 million tons of water storage capacity. In response, the Japanese government announced on April 13, 2021, that it plans to discharge the contaminated water into the sea from 2023. This study evaluates the amount of the contaminated water that has passed through the ALPS and reviews the preparations and related facilities for ocean discharge after diluting the contaminated water. In addition, it is intended to forecast the various impacts of ocean discharge.