Japan Has Released Over 172,000 Tons of Fukushima Water Into the Pacific, With Millions More Tons Still to Go

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Three years after Japan began releasing treated radioactive water from the damaged Fukushima Daiichi nuclear power plant into the Pacific Ocean, the total volume discharged has reached 172,700 tons across 22 release cycles.

The program, operated by Tokyo Electric Power Company Holdings (TEPCO), is intended to clear space at the site for facilities needed to remove melted nuclear fuel debris from the reactors. The company expects the discharge operation to continue until 2051.

The releases have reduced the volume of treated water stored at Fukushima by 7.6%, but about 1.24 million tons remain in roughly 1,000 tanks at the facility, according to Japan Today.

The Fukushima disaster began in March 2011, when a massive earthquake and tsunami caused severe damage to the nuclear plant. Water must still be used to cool melted fuel inside the damaged reactors, generating about 60 tons of radioactive wastewater each day.

Before discharge, the contaminated water is processed through an advanced liquid processing system that removes most radioactive substances. The remaining water is diluted with seawater until its tritium concentration falls below one-fortieth of the limit permitted under Japanese safety standards.

The diluted water is released from a point about one kilometer offshore. TEPCO first transfers batches into separate tanks, where radioactive concentrations are measured before the water is discharged in quantities of roughly 7,800 tons.

Four releases took place during fiscal 2023, followed by seven each in fiscal 2024 and 2025. TEPCO plans eight releases during fiscal 2026, with four already completed.

The International Atomic Energy Agency and Japanese authorities are monitoring the operation. Monitoring results reported so far have not detected abnormal tritium concentrations in nearby seawater or seafood.

The program has nevertheless faced strong opposition from fishing communities and governments abroad. China imposed a blanket ban on Japanese seafood imports when the releases began. Although Beijing lifted the ban for most of Japan in June 2025, imports from Fukushima and nine other prefectures remain excluded.

Russia and several other markets also maintain restrictions. TEPCO has paid about 96.7 billion yen, or roughly $608 million, in compensation across approximately 1,100 cases as of August 5, including claims linked to lost seafood exports.