IAEA: Tritium levels in discharged Fukushima water well below limits

Before being released into the ocean, water recovered from the damaged Fukushima plant is treated to remove radionuclides other than tritium using the Advanced Liquid Processing System (ALPS) then diluted with seawater. According to the IAEA, the tritium concentration in the diluted ALPS-treated water is far below the operational limit of 1,500 becquerels per liter and is in line with international safety standards.

To not exceed the operational limit of 1,500 Bq/L due to analysis uncertainty and instrument discrepancies, TEPCO limits the concentration of tritium in discharge water to 700 Bq/L. As of March 17, an IAEA online monitor website indicated discharge tritium concentrations of 463 Bq/L.

Latest batch: This latest batch of released ALPS-treated water is TEPCO’s seventh discharge for fiscal year 2024 and the 11th batch to be released since the company began discharging water in August 2023. According to TEPCO, approximately 54,600 cubic meters of treated water will have been released in FY2024, with an annual tritium discharge volume of approximately 14 trillion Bq.

The IAEA said its experts stationed at the agency’s Fukushima office conducted an independent on-site analysis of samples from the treated water of the previous 10 batches and confirmed that the tritium concentration in the diluted water is far below the operational limits and is in line with international safety standards.

In a comprehensive report issued on July 4, 2023, before the discharge began, the IAEA’s safety review found that Japan’s plan for handling the treated water was consistent with international safety standards and that the release as planned would have a negligible radiological impact to people and the environment. In line with Japan’s plans, the ALPS-treated water is being released from the Fukushima site in a series of batches over the next decades.