Corrosion discovered in tanks holding treated radioactive water at Fukushima nuclear power plant

Corrosion has been discovered on the inside of tanks used to store treated radioactive water at the Fukushima Daiichi nuclear power plant, which is currently decommissioning. The operator of the plant, Tepco, confirmed this issue. Tepco stated that while the tanks’ strength is not compromised, some of the containers installed over a decade ago have become obsolete. As a result, Tepco will continue inspecting the tanks to ensure their integrity.

In August 2023, Tepco began releasing wastewater into the sea, sparking protests from local fishermen and China. Despite assurances that all radioactive material, except tritium, has been filtered out of the water, concerns remain. Tritium is difficult to separate from water, but Tepco and the International Atomic Energy Agency (IAEA) assert that the levels present in the wastewater are harmless.

During a routine check in March, corrosion and peeling paint were found in three tanks that had been emptied after pumping. These tanks had been used for storing treated radioactive water since 2016. Investigations determined that the corrosion does not affect the tanks’ structure, and no leaks were detected. Tepco informed the IAEA about the findings and continues to conduct annual inspections of the tanks’ exteriors for abnormalities.

Due to the impossibility of inspecting the inside of tanks still holding treated water without underwater robots, Tepco focuses on external inspections to identify any issues that may arise. The decommissioning of the Fukushima nuclear power plant, destroyed in 2011 by a tsunami, is an ongoing process that is expected to take decades.