A team of South Korean experts is at the crippled Fukushima Daiichi nuclear power plant to assess the safety of Japan's plan to release treated and diluted water into the ocean.
The delegation of about 20 members includes senior officials of South Korea's Nuclear Safety and Security Commission, as well as marine environment specialists.
On Tuesday and Wednesday, they will look at how the treated water is being stored, the results of analyses and the construction of facilities to release the treated water.
The plant operator, Tokyo Electric Power Company, is preparing to start releasing water by around July or August.
The treated water will be diluted to reduce tritium levels to about one-seventh of the World Health Organization's safety standards for drinking water before it is released into the ocean.
The South Korean delegation came to Japan following an agreement reached at a summit meeting between the two countries on May 7.
The members arrived on Sunday and will stay through Friday. On Monday, officials of the Economy, Trade and Industry Ministry, the Foreign Ministry and TEPCO briefed them about the progress of the plan.
Japan intends to gain understanding and dispel concerns in South Korea through the delegation's visit in addition to a safety assessment by the International Atomic Energy Agency.
The South Korean government says the purpose of the visit is to meticulously verify the effects on South Korean waters and marine produce and to immediately implement necessary measures.