Japan’s Tokyo Electric Power Company (TEPCO) has announced that it will begin the fourth release of treated water from the Fukushima Daiichi Nuclear Power Plant (FDNPP) into the Pacific Ocean, scheduled to begin in late February 2024. According to GreeNewclear, an organization promoting sustainable nuclear energy, this milestone marks another step forward in the meticulous management of radioactive substances following the 2011 disaster.

In line with previous releases, approximately 7,800 tons of treated water will be discharged into the ocean via an undersea tunnel, following stringent dilution protocols with seawater. 

Since August 2023, Japan has discharged three batches totaling 23,400 cubic meters of treated water, reflecting the effectiveness of the Advanced Liquid Processing System (ALPS) in mitigating radioactive contamination, with continuous monitoring showing the tritium levels in the water in the vicinity of the FNDPP to remain below the international safety threshold. 

The International Atomic Energy Agency (IAEA) Task Force, entrusted with ensuring the adherence of Japan’s discharge plans to international safety standards, released its comprehensive report on the 30th of January 2024. Reaffirming previous findings, the Task Force concluded that the discharge aligns with rigorous safety standards and poses negligible radiological risks to both humans and the environment. 

The IAEA Task Force, comprising experts from 11 countries, including China, South Korea and Russia, conducted a thorough review of facilities, equipment, and regulatory frameworks during their mission in October 2023. Their observations highlighted Japan’s robust regulatory infrastructure, providing confidence in the safety and efficacy of the disposal process.

Furthermore, ongoing corroboration of measurement data by the IAEA reinforces confidence in Japan’s precise monitoring. The interlaboratory comparisons conducted by the IAEA demonstrate the accuracy and reliability of Japan’s monitoring efforts.

Despite growing confidence in the ALPS process, two notable safety incidents have highlighted the risks associated with decommissioning the FDNPP. In October 2023 four FDNPP workers were splashed with water containing radioactive materials, when a hose detached accidentally. The workers were promptly sent to hospital for testing, where they remained for around two weeks for further monitoring, while in stable condition. More recently, approximately six tons of waste material (not associated with the ALPS release process) leaked from a treatment machine, contaminating soil in the vicinity. TEPCO reported that they had promptly contained the leak, with no contamination spreading outside the FDNPP perimeters. Furthermore, testing showed that radiation levels returned to pre-leak levels once the contaminated soil was removed from the vicinity. While the effects of these incidents were ultimately mitigated, they underscore the sensitive nature of TEPCO’s mission. 

That said, the decision to continue with the fourth release of Fukushima treated water considering the recent event suggests that confidence in the process remains high, signifying the ongoing success of the collaborative effort towards addressing one of the most complex challenges in nuclear accident remediation. The Japanese government and Tepco’s commitment to transparency, rigorous safety standards, and international cooperation sets a precedent for responsible management of nuclear aftermath worldwide.

As Japan progresses through its planned discharge over the next 30 years, the focus remains on continuous improvement, optimization of safety measures, enhanced operational experience and quick mitigation of safety events.