D-Day for Japan's Contaminated Water Discharge... Government: "Public Health First, Monitoring System Operational"

460t Discharge per Day, 7,800t Over 17 Days
Radioactive Water to Enter Korean Waters in 4-5 Years
Strengthened Radiation and Seafood Testing
Discharge Data Shared Hourly

As Japan began discharging contaminated water from the Fukushima Daiichi Nuclear Power Plant into the ocean on the afternoon of the 24th, our government has stepped up its response measures. The discharge comes two years and four months after then-Prime Minister Yoshihide Suga decided in April 2021 to dispose of the contaminated water by releasing it into the ocean. The contaminated water, stored in tanks on the Fukushima Daiichi Nuclear Power Plant site after passing through the Advanced Liquid Processing System (ALPS), is diluted with seawater and discharged into the sea in front of the plant through an approximately 1 km-long underwater tunnel. Our government plans to prioritize public safety by strengthening monitoring and reviewing the post-discharge surveillance system as the discharge begins.

460 tons per day, 7,800 tons over 17 days discharged

The first checkpoint for contaminated water discharge is ALPS. The Japanese government removes radioactive substances harmful to humans through ALPS. After passing through ALPS, 62 types of radioactive materials, including cesium and strontium, are removed. However, even after ALPS treatment, radionuclides such as tritium (a form of hydrogen-3) and trace amounts of carbon-14 remain.

The ALPS-purified contaminated water is transferred to the 'K4 tank,' where the concentration of radioactive substances is measured. If the concentration exceeds the standard, the water is sent back to ALPS for repeated processing. At this stage, homogenization occurs. Since the amount of radioactivity varies greatly in each batch of contaminated water, the water is thoroughly mixed and sampled to accurately verify the concentration.

Contaminated water that meets the standards is moved via transfer pumps to a tank near the sea. Seawater is introduced into the tank to dilute the tritium that ALPS cannot remove. Dilution continues until the tritium concentration reaches about 1,500 becquerels (Bq) per liter. The World Health Organization (WHO) standard for tritium in drinking water is 10,000 Bq per liter, and the tritium discharge standard for Korean nuclear power plants is below 40,000 Bq per liter.

After completing all procedures and measuring tritium levels, the treated contaminated water is transported through a tunnel located 12 meters below the sea surface to a point 1 km offshore, where it is finally discharged into the ocean. If there are no abnormalities in the treatment process, 460 tons per day will be discharged over 17 days, totaling 7,800 tons initially. The current volume of accumulated contaminated water is approximately 1.34 million tons, and the total discharge period is at least 30 years.

Contaminated water expected to reach Korean waters in 4-5 years... Strengthened radiation and seafood inspections

The government predicts that the discharged contaminated water will enter Korean waters in 4 to 5 years. Examining the movement path, the contaminated water travels via the Kuroshio Current into the North Pacific Ocean. The North Pacific Current splits into two branches along the coasts of Canada and Alaska: the Oyashio Current and the California Current. The Oyashio Current moves toward the Russian coast and then returns to Japan, while the California Current meets the North Equatorial Current, circulates the Pacific, and flows back into the Kuroshio Current as well as the East Sea and West Sea. Experts agree that as the contaminated water passes through multiple currents before reaching our shores, the tritium concentration will decrease to a low level below one-millionth of its original concentration.

The government has established a monitoring system focusing on the entry points along the currents near Pacific island nations leading to our coast. To strengthen surveillance of our waters, the number of existing marine radiation monitoring points was increased from 92 to 108 at the end of last month, operating a total of 200 points. The scope of marine radiation monitoring will also be significantly expanded. Starting next year, surveys will be conducted in waters near Pacific island countries and the open waters of the northwest Pacific near Japan. The survey will begin with 10 points near Pacific island nations, where the North Equatorial Current connected to the Kuroshio Current directly flows into our waters, to check radiation levels.

Specifically, two zones have been set along the contaminated water’s path from the Fukushima Daiichi Nuclear Power Plant. Zone A includes five points approximately 500 to 1,000 km away, and Zone B includes three points approximately 1,100 to 1,500 km away. This setup will enable practical monitoring of radiation level changes in international waters. Additionally, as part of marine radiation monitoring, a research infrastructure will be established with Pacific island countries by 2025 to promote joint marine radiation research.

Prime Minister Han Duck-soo is delivering a statement on the morning of the 23rd at the Seoul Government Complex to prevent the recurrence of "abnormal motive crimes." The statement was attended by Minister of the Interior and Safety Lee Sang-min, Minister of Justice Han Dong-hoon, Minister of Health and Welfare Cho Kyu-hong, and Commissioner of the National Police Agency Yoon Hee-geun. Photo by Jo Yong-jun jun21@

Discharge data shared every hour

The government will verify key data at each stage of Japan’s discharge process to ensure there are no defects. Japan shares data every hour in cooperation with the International Atomic Energy Agency (IAEA). The data includes radiation concentration measurements from intake, discharge, and transfer facilities; flow rates of contaminated water transferred to dilution facilities; seawater pump flow rates; and tritium concentrations after dilution. Additionally, the Japanese government publicly discloses 69 radionuclide values measured in the K4 tank, tritium concentrations measured in the tank before discharge, and tritium concentrations measured in seawater pipes during discharge.

Korean personnel are regularly dispatched to the IAEA field office established at the Fukushima nuclear plant. This follows a request made during the Korea-Japan summit on the 12th of last month to involve Korean experts in the discharge inspection process. The IAEA shares information related to contaminated water discharge with the Korean government and holds regular video conferences to provide comprehensive explanations of various data. A dual hotline system has been established for rapid information sharing. In case of abnormalities, regulatory and diplomatic authorities in Korea and Japan activate their respective hotlines to communicate. Additionally, in emergencies, information is quickly shared through established contact channels with the IAEA.

If radioactive substance concentrations exceed standards or other issues arise during monitoring, the Korean government will immediately request Japan to halt the discharge. Japan will notify the relevant facts and data through diplomatic hotlines. Should Japan proceed with the discharge despite this, the Korean government intends to seek urgent measures from the International Tribunal for the Law of the Sea under international law and is prepared to file a lawsuit.

Prime Minister Han Duck-soo emphasized at a press briefing held at the Government Complex Sejong the previous day, “The discharge issue prioritizes public health and safety, and securing these two is clear,” adding, “We will complete all procedures to verify whether Japan’s discharge actions meet scientific standards.”

This content was produced with the assistance of AI translation services.